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Uhrík, Patrik. "Implementace kogeneracni jednotky do siti "Smart Heating and Cooling Networks"." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2017. http://www.nusl.cz/ntk/nusl-318635.
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The aim of the Master‘s thesis was to create a computational model for integration of the cogeneration unit into the smart thermal network. For the better use of waste heat from the selected cogeneration unit MOTORGAS MGM250 during the summer period, the absorption circuit was dimensioned and the appropriate trigeneration computational model was formed. In the theoretical part, the function, operation and heat performance of the cogeneration unit as well as the suitability of the connection of the cogeneration unit with the absorption chiller during the summer period were described. In the practical part, the operational data of the Faculty of Mechanical Engineering of the Brno University of Technology and the theoretical performance data from created cogeneration and trigeneration computational models were compared. Based on this comparison, the conclusion about the suitability of use of both computational models was made.
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SAMUELSSON, ANDERS, and DANIEL STEUER. "Model predictive control in heating and cooling networks : A case study of an urban district in Stockholm." Thesis, KTH, Skolan för industriell teknik och management (ITM), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-299439.
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This work presents a model predictive control system for heating and cooling supply planning in an urban heating and cooling network. The control approach addresses the need for strategic operation of distributed production technologies and thermal energy storage in increasingly complex heating and cooling networks. Predictive optimization handles this complexity with an optimization strategy taking future demand, prices, and energy source availability into consideration. The model predictive control is integrated in a model built in a co-simulation approach. The co-simulation approach allows for models to run in their own simulation environments, preserving their levels of detail. The model is adapted to a case study of an urban district under construction in Stockholm. Yearly simulations of the network and comparisons of the outcome when operated by the model predictive controller and by a reference rule-based controller are performed. The results show performance improvements in the form of reduced operational costs of 9.7 % and 18.8 % reduced carbon emissions, depending on how the objective function of the model predictive controller is formulated. An objective function aiming to minimize district heating imports is also formulated. While that objective function decreases the imports compared to the other objective functions, it increases the imports compared with the reference scenario, albeit from an already low share in the total energy supply of 0.2 %. A sensitivity analysis is performed to investigate the robustness of the control system. The sensitivity analysis shows that the reference controller is not robustly programmed for variations in parameters compared with the model predictive controller, which performs consistently better with both increases and decreases of the parameter sizes. Future work could include detailed modelling in other simulation tools integrated in the co-simulation platform. Another possibility is developing a closed-loop system approach which would include, for example, feedback from the buildings’ indoor temperatures. This would allow for the utilisation of the buildings’ thermal mass as thermal energy storage. Lastly, more detailed economic and environmental calculations, such as life-cycle analysis or investment calculations, would further emphasize the real-world applicability of the findings.Det här arbetet presenterar ett Model Predictive Control system för planering av värme- och kyltillförsel i ett urbant värme- och kylnät. Distribuerade energiresurser och termisk värmelagring leder till ökad komplexitet i planering och drift av framtidens värme- och kylnät. Prediktiv optimering hanterar komplexitet med en optimeringsstrategi som tar hänsyn till framtida efterfrågan, priser och tillgänglighet av energiresurser. Model Predictive Control systemet är integrerat i en modell uppbyggt i en Co-Simulation miljö. Co-Simulation möjliggör detaljerad modellering av olika delsystem i dess specifika simulerings miljö för att bevara dess detaljnivå. Modellen är anpassad till en fallstudie av ett urbant distrikt under uppbyggnad i norra Stockholm. Årliga simuleringar av distriktet genomfördes. Därefter jämfördes resultat mellan simuleringar med Model Predictive Control systemet med ett konventionellt regel-baserat kontrollsystem. Tre målfunktioner var formulerade för Model Predictive Control systemet. Den första att minska driftkostnader för systemet, den andra att minska koldioxidutsläpp och det sista att minska importen från fjärrvärmenätet. Den första målfunktionen ger en minskning på 9.7 % i driftkostnader, den andra ger minskade koldioxidutsläpp på 18.8 %. Den tredje och sista däremot uppnår inte målet och ökar importen från fjärrvärmesystem jämfört med det konventionella regel-baserade kontrollsystemet. Utöver det så är en känslighetsanalys genomförd för att visa på robusthet av kontrollsystemen. Den visar att det Model Predictive Control systemet anpassar sig till förändringar i parametrar bättre än det andra kontrollsystemet. Framtida arbeten inom området kan inkludera mer detaljerade modellering av de olika teknologierna inkluderade i studien. En annan möjlighet är utveckling av ett återkopplingssystem från byggnadernas inomhustemperatur. Det skulle möjliggöra användningen av byggnadens termiska massa som termisk energilagringssystem. Slutligen, mer detaljerad ekonomiska beräkningar och miljöberäkningar, såsom life-cycle analysis eller investeringskalkylering skulle utveckla resultaten från arbetet också.
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Yuwardi, Yuwardi. "Absorption cooling in district heating network: Temperature difference examination in hot water circuit." Thesis, KTH, Kraft- och värmeteknologi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-125068.
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Absorption cooling system driven by district heating network is relized as a smart strategy in Sweden. During summer time when the heating demand is low, the excessive hot water can be directly sold to drive absorption chillers instead of decreasing its production. In addition, this is also one answer to satisfy the cooling demand in more environmentally way since currently only around 26% of cooling demand in Sweden is satisfied by district cooling, the rest is fulfilled by individual air conditioning. Realizing this potential, the purpose of this study is to examine the returning hot water temperature in the district heating network with supply temperature of 70°C and also the effect to the absorption chiller’s COP. Through the simulation result, it is found out that the lowest possible returning water temperature is 55 °C at COP 0,69 with heat rejection (re-cooling) temperature water at 22 °C. This implies that the desired returning hot water temperature of 47 °C cannot be achieved. The lower returning hot water temperature is preferable since it gives the district heating network benefit in term of less distribution pump work, and energy recovery for the condensation process at central heating plant.
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Javed, Abbas. "Random neural network based smart controller for heating, cooling and ventilation in domestic and non-domestic buildings." Thesis, Glasgow Caledonian University, 2016. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.743891.
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Oppelt, Thomas. "Modell zur Auslegung und Betriebsoptimierung von Nah- und Fernkältenetzen." Doctoral thesis, Universitätsbibliothek Chemnitz, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-179211.
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Fernkälte bietet das Potenzial, wirtschaftlich und ökologisch vorteilhaft zur Deckung des stetig zunehmenden Klimakältebedarfs beizutragen. Im Rahmen dieser Arbeit wurde ein dynamisches thermohydraulisches Netzmodell „ISENA“ entwickelt, mit dem während der Planung und des Betriebs von Fernkältesystemen auftretende Fragen, beispielsweise in Bezug auf Wirtschaftlichkeit und Energieeffizienz, beantwortet werden können. Das Netzmodell setzt sich aus einem quasistationären hydraulischen Modell und einem instationären thermischen Modell zusammen, das auf der Verfolgung von Wasserpfropfen durch das gesamte Netz basiert (Lagrange-Ansatz). Mit diesem Modellierungsansatz können numerische Fehler sowie Bilanzungenauigkeiten vermieden werden, sodass sich eine höhere Ergebnisgüte im Vergleich zu bisher bekannten Netzmodellen erreichen lässt. Ebenfalls neu entwickelt wurde das Teilmodell zur Abbildung der Wärmeströme über die Wände unterirdischer Rohrpaare (Kälteverluste und -gewinne). Dieses Modell erlaubt die Bestimmung der instationären Rohrwand-Wärmeströme für wärmegedämmte unterirdische Rohrpaare, Rohrpaare mit gedämmtem Vor- und ungedämmtem Rücklauf sowie ungedämmte Rohrpaare. Anhand von Validierungs- und Verifikationsrechnungen wird gezeigt, dass ISENA verlässliche Ergebnisse liefert und für die praktische Anwendung geeignet ist. Abschließende Beispielrechnungen geben einen Einblick in die Untersuchungsmöglichkeiten, die das neue Modell bietet – unter anderem im Hinblick auf den Vergleich von Pumpenregelungsvarianten, den Einfluss von Rohrdämmung und Erdreicheigenschaften auf Kälteverluste und -gewinne sowie die Einbindung von Hochtemperatur-Kälteverbrauchern in den NetzrücklaufDistrict cooling can provide economic and ecological benefits while supplying the increasing cooling demand for air conditioning. In the present thesis, a dynamic thermo-hydraulic model “ISENA” is presented which may be used in order to answer questions arising during design and operation of district cooling networks—e. g., that are related to economic and energy efficiency. The network model consists of a quasi-static hydraulic module and a transient thermal module being based on the tracking of water segments through the entire network (Lagrangian method). With this approach, numerical errors and inaccuracies in the balance of conserved quantities could be avoided, which eventually leads to a better reliability of the results as compared to that obtained from other network models. Additionally, a new sub-model has been developed for predicting the transient heat flux through the walls of buried pipes in order to model thermal gains and losses. This model covers un-insulated, insulated and combinations of insulated as well as un-insulated pipes. Calculations performed for the purpose of validation and verification are presented in order to demonstrate that ISENA provides reliable results and hence is suitable for practical applications. Finally, example simulations show the various possibilities provided by the new model—for example, concerning the comparison of different strategies for pump control, the influence of pipe insulation and soil properties on thermal gains and losses as well as the connection of buildings equipped with high temperature cooling systems to the return line of the network
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Soderlund, Matthew Roger. "Congeneration dedicated to heating and cooling." Thesis, Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/17672.
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Sikora, Michal. "Inovace systému chlazení točivých elektrických strojů s využitím CFD metod." Doctoral thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2011. http://www.nusl.cz/ntk/nusl-233962.
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This thesis deal with design and implementation of innovative cooling method, intended primarily for medium-power synchronous generators. The main objective of this proposal is to remove the large heat exchanger connected to generator. This heat exchanger unduly increases the space requirements for the machine location. The proposed solution is to use a direct water-cooled stator. It is assumed that the rotor winding will be still cooled by air. Unlike current cooling system, the hot air from the rotor can be cooled in smaller cooler inside the generator. In this work are described methods which can be used for design of water cooling basic parameters, taking required temperatures into account. A small induction motor was selected for practical verification of the proposed cooling concept. This motor was modified into two variants - related to the old cooling of synchronous generators and related to the proposed solution. Both of these variants were measured and compared with each other. Subsequently, CFD models of these two variants were set up. Measured temperatures were used for debugging of models and identification of material properties of components of these machines. The final model of water-cooled variant also makes it possible to simulate the work of motor for higher performance and to determine the overload compared with the old cooling variant. Some knowledge and experience obtained from the small water-cooled induction machine were used in the design of water-cooling for large synchronous generator. In a similar way, CFD models of the old variant of cooling and proposed variant of water- cooling were created. Although these models were not verified by actual measurements on the generators, the results indicated that the application of water-cooling in this type of machine is appropriate and provides many benefits.
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Dong, Bing. "Integrated Building Heating, Cooling and Ventilation Control." Research Showcase @ CMU, 2010. http://repository.cmu.edu/dissertations/4.
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Current research studies show that building heating, cooling and ventilation energy consumption account for nearly 40% of the total building energy use in the U.S. The potential for saving energy through building control systems varies from 5% to 20% based on recent market surveys. In addition, building control affects environmental performances such as thermal, visual, air quality, etc., and occupancy such as working productivity and comfort. Building control has been proven to be important both in design and operation stages.
Building control design and operation need consistent and reliable static and dynamic information from multiple resources. Static information includes building geometry, construction and HVAC equipment. Dynamic information includes zone environmental performance, occupancy and outside weather information during operation.. At the same time, model-based predicted control can help to optimize energy use while maintaining indoor set-point temperature when occupied. Unfortunately, several issues in the current approach of building control design and operation impede achieving this goal. These issues include: a) dynamic information data such as real-time on-site weather (e.g., temperature, wind speed and solar radiation) and occupancy (number of occupants and occupancy duration in the space) are not readily available; b) a comprehensive building energy model is not fully integrated into advanced control for accuracy and robustness; c) real-time implementation of indoor air temperature control are rare. This dissertation aims to investigate and solve these issues based on an integrated building control approach.
This dissertation introduces and illustrates a method for integrated building heating, cooling and ventilation control to reduce energy consumption and maintain indoor temperature set-point, based on the prediction of occupant behavior patterns and weather conditions. Advanced machine learning methods including Adaptive Gaussian Process, Hidden Markov Model, Episode Discovery and Semi-Markov Model are modified and implemented into this dissertation. A nonlinear Model Predictive Control (NMPC) is designed and implemented in real-time based on Dynamic Programming. The experiment test-bed is setup in the Solar Decathlon House (2005), with over 100 sensor points measuring indoor environmental parameters such as temperature, relative humidity, CO2, lighting, motion and acoustics, and power consumption for electrical plugs, HVAC and lighting. The outdoor environmental parameters, such as temperature, relative humidity, CO2, global horizontal solar radiation and wind speed, are measured by the on-site weather station. The designed controller is implemented through LabVIEW.
The experiments are carried out for two continuous months in the heating season and for a week in cooling season. The results show that there is a 26% measured energy reduction in the heating season compared with the scheduled temperature set-points, and 17.8% energy reduction in the cooling season. Further simulation-based results show that with tighter building façade, the cooling energy reduction could reach 20%. Overall, the heating, cooling and ventilation energy reduction could reach nearly 50% based on this integrated control approach for the entire heating/cooling testing periods compared to the conventional scheduled temperature set-point.
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Bol, Bullen A. D. "A pervaporation membrane absorption cooling heating system." Thesis, University of Nottingham, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.289081.
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Poulis, P. D. A. "Radiant wall and floor heating and cooling." Thesis, Open University, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.384588.
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Karlström, Petra. "Soft Heating and Cooling in Humid Climates." Thesis, KTH, Byggnadsteknik, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-35098.
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VILAFRANCA, MANGUÁN ANA. "Convesion of industrial compression cooling to absorption cooling in an integrated district heating and cooling system." Thesis, University of Gävle, University of Gävle, Department of Technology and Built Environment, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-4145.
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Astra Zeneca plant in Gärtuna has many compression cooling machines for comfort that consume about 11.7 GWh of electricity per year. Many of the cooling machines are old; due to the increase of production of the plant, cooling capacity was limited and new machines have been built. Now, the cooling capacity is over-sized. Söderenergi is the district heating plant that supplies heating to Astra Zeneca plant. Due to the strict environmental policy in the energy plant, last year, a bio-fuelled CHP plant was built. It is awarded with the electricity certificate system.
The study investigates the possibility for converting some of the compression cooling to absorption cooling and then analyzes the effects of the district heating system through MODEST optimizations. The effects of the analysis are studied in a system composed by the district heating system in Södertälje and cooling system in Astra Zeneca. In the current system the district heating production is from boiler and compression system supplies cooling to Astra Zeneca. The future system includes a CHP plant for the heating production, and compression system is converted to absorption system in Astra Zeneca. Four effects are analyzed in the system: optimal distribution of the district heating production with the plants available, saving fuel, environmental impact and total cost. The environmental impact has been analyzed considering the marginal electricity from coal condensing plants. The total cost is divided in two parts: production cost, in which district heating cost, purchase of electricity and Emissions Trading cost are included, and investment costs. The progressive changes are introduced in the system as four different scenarios.
The introduction of the absorption machines in the system with the current district heating production increases the total cost due to the low electricity price in Sweden. The introduction of the CHP plant in the district heating production supposes a profit of the production cost with compression system due to the high income of the electricity produced that is sold to the grid; it profit increases when compression is replaced by absorption system. The fuel used in the production of the future system decreases and also the emissions. Then, the future system becomes an opportunity from an environmental and economical point of view. At higher purchase electricity prices predicted in the open electricity market for an immediately future, the future system will become more economically advantageous.
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Martin, Guillaume. "District Heating Networks Design." Thesis, KTH, Skolan för industriell teknik och management (ITM), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-264257.
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District heating networks are a solution to decrease the amount of CO2 emission in the atmosphere and a mean to increase the share of renewable energy in the energy mix. This degree project, conducted at Engie Réseaux, investigates the best options to design them. The challenges and the constraints of their design will be developed and the tools created to achieve it will be presented. This thesis exposes the major climatologic, economic, and energetic parameters to take into account when designing a network and shows the methodology used in these three fields.Fjärrvärmenät är en lösning för att minska mängden koldioxidutsläpp i atmosfären och ett medel för att öka andelen förnybar energi i energimixen. Detta examensarbete, utfört på Engie Réseaux, undersöker de bästa alternativen för att designa dem. Svårigheterna och begränsningarna i deras utformning kommer att utvecklas och de verktyg som skapats för att uppnå det kommer att presenteras. Denna avhandling visar de viktigaste klimatologiska, ekonomiska och energiska parametrarna att ta hänsyn till vid utformning av ett nätverk och visar den använda metodiken.
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Chan, Hoy-Yen. "Solar facades for heating and cooling in buildings." Thesis, University of Nottingham, 2011. http://eprints.nottingham.ac.uk/12319/.
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The aim of this thesis is to study the energy performance of a building integrated heating and cooling system. The research objectives are to investigate the system operating characters, to develop mathematical models for the heating and cooling systems, to demonstrate the technologies experimentally, to identify the best designs for a combined system and to investigate the cost effectiveness of the system. The main components of the systems are the aluminium plate façade and the building wall behind it, these form a plenum between them and the air is then heated or cooled as it flows through this plenum. Mathematical models were developed based on the energy balance equations and solved by matrix inversion method. These models were then validated with experimental results. The experiments were carried out in the laboratory with a facade area of 2m2. Two designs of facade were tested, i.e. flat and transpired plates. Results showed that the transpired design gave better thermal performance; the system efficiency for the flat plate was only about 30%, whereas it was about 85% for the transpired plate. On the other hand, a cooling system with double plenums was found to be better than a single plenum. Thus, a transpired plate with two plenums was identified as the best design for space heating and cooling. The cooling efficiency was nearly 2.0 even at low solar radiation intensity. A simulation study was carried out by assuming a 40m2 of façade was installed on an office building in London. The yearly energy saving was estimated as 10,877kWh, which is equivalent to 5,874kgCO2/year of emission avoidance. The system is calculated to cost about £70/m2, and for a discount rate of 5% and 30 years of lifetime, the payback period for this system would be less than a years.
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Markowicz, Catarina. "Analysis of Cooling Capability in Polish District Heating Substations." Thesis, Uppsala universitet, Institutionen för teknikvetenskaper, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-173144.
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For a district heating company it is of importance to have an efficient and well performing system. A central part in the work to lower temperature levels in district heating networks is to acknowledge and improve cooling capability in substations. The aim of this thesis is to analyse substations in Polish district heating systems in order to identify reasons of poor cooling and to present suggestions of implementable measures. Furthermore, the economical saving potential from an improved cooling is evaluated. The analysis was carried out for two of the five Polish companies included in this report; Sydkraft EC Slupsk and MEC Koszalin. It was followed by two scenarios created for evaluation of improvement possibilities based on calculated financial savings from reduction of distribution heat losses and distribution pumping. The results show that there are significant improvement possibilities. From the carried out scenarios a saving potential between 15 000 to 20 000 PLN/substation is possible to achieve for selected worst substations, if their individual annual average cooling is set to 30°C. The analysis further shows that causes of poor cooling in substations are highly individual but points out that customer owned substations are represented in the majority of worst substations.
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Saman, Namir Fathullah. "Analysis of building heating and cooling requirements after shutdown." Diss., The University of Arizona, 1989. http://hdl.handle.net/10150/184867.
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The heating and cooling requirements after a shutdown period of the heating ventilating and air conditioning (HVAC) systems in buildings are studied through an analytical model. The parameters affecting the preconditioning and storage loads which are of particular importance are identified. A mathematical computer model is developed to facilitate the analysis of the shutdown loads. Zones are grouped in terms of heavy, medium and light weight construction for the study. For a specified zone, the ratio of the inside surface area to the outside exposed area, A(s)/A(w), is an important parameter in predicting the additional loads resulting from system shutdown. The computer model is validated with known computer programs, namely DOE-2, BLAST, and DARE-P. A simplification to the model is proved to be adequate for the study. The zones with similar weight characteristics and the same A(s)/A(w) ratio, prove to have the same temperature profiles during the shutdown period, provided that they are at the same ambient conditions. Design guidance and procedures for predicting the preconditioning and storage loads using the models are developed. In addition, the use of DOE-2 and ASHRAE weighting factor method for shutdown load predictions is demonstrated for generic and custom applications.
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Amara, Sofiane. "Novel and ancient technologies for heating and cooling buildings." Doctoral thesis, Luleå tekniska universitet, Arkitektur och vatten, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-16977.
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The basic issue of this thesis concerns one of the fundamental problems of the future of our society: How to meet the energy requirements for a large and growing world population while preserving our environment? This question is important for the world and the answers are complex and interwoven.Conventional energy sources, fossil and fissile, are polluting in the present and in the future: they erode the environment and their resources are limited. Renewable energy (hydro, wind, solar, geothermal) constitutes a minimum of pollution in the different energy systems. The technologies for using renewable energy are well known though further development and progress are made. This development also requires behavioural change, adaptation, and above all political will. The transition from an economy based on fossil energy to an economy based on renewable energy appears necessary for the protection of the environment. The cost of renewable energy is often represented as an obstacle but remains competitive in the long run.The development and availability of renewable energy, which varies because of its spatial and temporal distribution, require an adaptation of lifestyle, habits, habitat design (passive bioclimatic houses), urban planning and transportation.The focus of this thesis was to apply renewable energy in an area with hot summers and cold winter, a climate like that in the northwest of Algeria. In order to provide improved comfort in the buildings and also economic development in this area, the energy demand for heating and cooling was analyzed in the ancient city of Tlemcen. To supply domestic hot water and space heating, water must be simultaneously available at two different temperature levels. Cold water temperature, close to that of the atmosphere, and hot water between 50 and 60°C. An interesting feature of the preparation of hot water is the small variation of requirements during the year, unlike that to heating. The preparation of hot water is one of the preferred applications of solar energy in the building for several reasons. For this reason an experimental study of the thermal behaviour of a domestic hot water storage tank was undertaken. The phenomena that affect the thermal behaviour of tank especially the coupling between the solar collector and storage tank was studied. This study included concentrating solar collector in which optical fibers were used to transport the energy to the storage tank. Another technology was introduced and developed for the heating and cooling of buildings in the desert involving an existing ancient irrigation system called Fouggara. The novel idea is to use the Fouggara as an air conditioner by pumping ambient air through this underground system. Then air at a temperature of about 21°C would be supplied to the building for heating in the winter and cooling in the summer. This study shows the feasibility of using this ancient irrigation system of Fouggara and contributes to reducing and eliminating the energy demand for heating and cooling buildings in the Sahara desert.Godkänd; 2011; 20110920 (sofama)
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Alharbi, Abdulrahman. "Investigation of sub-wet bulb temperature evaporative cooling system for cooling in buildings." Thesis, University of Nottingham, 2014. http://eprints.nottingham.ac.uk/27806/.
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The work presented in this thesis investigates design, computer modelling and testing a sub-wet bulb temperature evaporative cooling system for space air conditioning in buildings. The context of this evaporative cooling technology design is specifically targeted at locations with a hot and dry climate such as that prevailing in most regions of Middle East countries. The focus of this technology is to address the ever-escalating energy consumption in buildings for space cooling using mechanical vapour compression air conditioning systems. In this work, two evaporative cooling configurations both based on sub-wet bulb temperature principle have been studied. Furthermore, in these designs, it was sought to adopt porous ceramic materials as wet media for the evaporative cooler and as building element and use of heat pipes as heat transfer devices. In the first test rig, the prototype system uses porous ceramic materials as part of a functioning building wall element. Experimental and modelling results were obtained for ambient inlet air dry bulb temperature of 30 and 35oC, relative humidity ranging from 35% to 55% and intake air velocity less than 2 (m/s). It was found that the design achieved sub-wet bulb air temperature conditions and a maximum cooling capacity approaching 242 W/m2 of exposed ceramic material wet surface area. The wet bulb effectiveness of the system was higher than unity. The second design exploits the high thermal conductivity of heat pipes to be integrated as an effective heat transfer device with wet porous ceramic flat panels for evaporative cooling. The thermal performance of the prototype was presented and the computer model was validated using laboratory tests at temperatures of 30 and 35oC and relative humidity ranging from 35% to 55%. It was found that at airflow rates of 0.0031kg/s, inlet dry-bulb temperature of 35oC and relative humidity of 35%, the supply air could be cooled to below the inlet air wet bulb temperature and achieve a maximum cooling capacity of about 206 W/m2 of wet ceramic surface area. It was shown that the computer model and experimental tests are largely in good agreement. Finally, a brief case study on direct evaporative cooling thermal performance and environmental impact was conducted as part of a field trip study conducted on an existing large scale installation in Mina Valley, Saudi Arabia. It was found that the evaporative cooling systems used for space cooling in pilgrims’ accommodations and in train stations could reduce energy consumption by as much as 75% and cut carbon dioxide emission by 78% compared to traditional vapour compression systems. This demonstrates strongly that in a region with a hot and dry climate such as Mina Valley, evaporative cooling systems can be an environmentally friendly and energy-efficient cooling system compared to conventional vapour compression systems.
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Al-Hinai, Hilal Ali Zaher. "Natural Cooling Techniques For Buildings." Thesis, Cranfield University, 1992. http://hdl.handle.net/1826/3591.
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Modern development in many Third World countries in the
hot regions of the world,, have been accompanied by the
construction of highly energy-wasteful buildings. The
interiors of these buildings have to be mechanically airconditioned
in order to achieve thermal-comfort conditions.
The consequence of this, has been the rapid increase in
electricity-generating plant capacity to match demand (of
which, for example at present in Oman, more than 70%
nationally is used for air-conditioning modern, energyinefficient
buildings).
The aim of this work was to find the most suitable way
of stabilising or even reducing the electricity demand in a
country like Oman. The first step taken to achieve this aim,
was to study and draw out lessons from the vernacular
architecture of the different climatic regions in Oman. This
has been followed by a literature survey that looks at
passive and active natural cooling techniques for buildings
in hot climates. Mathematical models were then developed to
analyze and compare those passive techniques that are most
suitable for an environment like that of Oman. Different ways
of reducing the heat gain through the roof were investigated
and compared. These include the addition of insulation,
shading, air-cooling of the roof when the ambient air
temperature is lower than that of the roof, and roof ponds.
Roof ponds were found to be the most effective of those
techniques analyzed. An improved design of the roof pond (the
Water Diode roof pond) that eliminates the need for covering
the roof pond during the day and uncovering it at night, was
suggested and analyzed. The analysis showed promising
results. Mathematical models were also developed to analyze and
compare dif f erent ways of reducing the heat gain through the
walls. These included the use of closed cavities, naturally
ventilated cavities, the addition of insulation, and the
effect of using brick as compared to concrete block. The
analysis suggested that the combination of a Water Diode roof
pond and insulated brick wall construction will reduce the
heat gain through the envelope of a single room by more than
90%, when compared to a room with un-insulated roof and
single-leaf concrete block walls.
An empirical validation of the mathematical models was
conducted. The results showed a good agreement between the
actual and predicted values. An economical analysis of the
commonly used roof and wall constructions in Oman, was also
conducted. This compared the life-cycle cost of nine
different construction techniques, with eight different airconditioning
schedules. The result of this analysis showed a
clear advantage of using roof insulation, reflective double
glazing, and insulated walls with brick outer-leaf and
concrete block inner-leaf.
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Clark, Craig R. "Sympathetic heating and cooling of trapped atomic and molecular ions." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/43757.
Full textAbstract:
Laser-cooled atomic ions have led to an unprecedented amount of control over the quantum states of matter. The Coulombic interaction allows for information to be transferred between neighboring ions, and this interaction can be used to entangle qubits for logic operations in quantum information processors. The same procedure for logic operations can be used for high resolution atomic spectroscopy, and is the basis for the most accurate atomic optical clocks to date. This thesis describes how laser-cooled atomic ions can impact physical chemistry through the development of molecular ion spectroscopy techniques and the simulation of magnetic systems by ion trap quantum computers.
A new technique developed for spectroscopy, Sympathetic Heating Spectroscopy (SHS), takes advantage of the Coulombic interaction between two trapped ions: the control ion and a spectroscopy ion. SHS uses the back action of the interrogating laser to map spectroscopy ion information onto the Doppler shift of the control ion for measurement. SHS only requires Doppler cooling of the ions and fluorescence measurement and represents a simplification of quantum logic spectroscopy. This technique is demonstrated on two individual isotopes of calcium: Ca-40(+) for cooling and Ca-44(+) as the spectroscopy ion.
Having demonstrated SHS with atomic ions, the next step was to extend the technique by loading and characterizing molecular ions. The identification of an unknown molecular ion is necessary and can be achieved by monitoring the change in motion of the two ion crystal, which is dependent on the molecular ion mass. The motion of two trapped ions is described by their normal modes, which can be accurately measured by performing resolved sideband spectroscopy of the S(1/2)-D(5/2) transition of calcium. The resolved sidebands can be used to identify unknown ions (atomic and molecular) by calculating the mass based on the observed value in axial normal mode frequencies. Again, the trapped molecular ion is sympathetically cooled via the Coulombic interaction between the Ca-40(+) and the unknown molecular ion. The sensitivity of SHS could be improved by implementing sympathetic sideband cooling and determining the heating by measuring single quanta of motion.
The ultimate limit of control would be the development of an ion trap quantum computer. Many theoretical quantum computing researchers have made bold claims of the exponential improvement a quantum computer would have over a classical computer for the simulation of physical systems such as molecules. These claims are true in principle for ideal systems, but given non-ideal components it is necessary to consider the scaling due to error correction. An estimate of the resource requirements, the total number of physical qubits and computational time, required to compute the ground state energy of a 1-D quantum Transverse Ising Model (TIM) of N spin-1/2 particles, as a function of the system size and the numerical precision, is presented. This estimate is based on analyzing the impact of fault-tolerant quantum error correction in the context of the quantum logic array architecture. The results show that a significant amount of error correction is required to implement the TIM problem due to the exponential scaling of the computational time with the desired precision of the energy. Comparison of this result to the resource requirements for a fault-tolerant implementation of Shor's quantum factoring algorithm reveals that the required logical qubit reliability is similar for both the TIM problem and the factoring problem.
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Marigny, Johan. "Analysis of simultaneous cooling and heating in supermarket refrigeration systems." Thesis, KTH, Tillämpad termodynamik och kylteknik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-44469.
Full textAbstract:
In this master thesis project, conventional supermarket refrigeration systems using R404A are compared with refrigeration system solutions using natural refrigerants such as carbon dioxide and ammonia. This systems analysis considers the behavior of those systems in floating condensing and heat recovery mode. System heating and cooling COP have been calculated by using computer simulation with the calculation software EES (Engineering Equation Solver). The impact of important parameters such as sub-cooling, external superheating and compressor discharge was also determined through the computer models.The estimation of the system annual energy consumptions shows that systems using natural refrigerant can compete with systems using artificial refrigerant by using heat recovery system such as heat pump cascade, heat pump cascade for sub-cooling, fixed pressure system and de-superheater. If the indirect emission of systems using natural refrigerant and artificial refrigerant is approximately similar, the direct emission for carbon dioxide systems and ammonia systems can be estimated to be 10000 times less important than R404A systems.Multi-unit refrigeration systems have also been studied in this project; it appears that in theory COP improvement of 10% is possible if the condensing temperature of each unit is controlled adequatelly.B
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Oliver, Jason Ryan. "A micro-COOLING, HEATING, AND POWER (m-CHP) INSTRUCTIONAL MODULE." MSSTATE, 2005. http://sun.library.msstate.edu/ETD-db/theses/available/etd-11092005-123751/.
Full textAbstract:
Cooling, Heating, and Power (CHP) is an emerging category of energy systems consisting of power generation equipment coupled with thermally activated components. The application of CHP systems to residential and small commercial buildings is known as micro-CHP (m-CHP). This instructional module has been developed to introduce engineering students to m-CHP. In the typical engineering curriculum, a number of courses could contain topics related to m-CHP. Thermodynamics, heat transfer, HVAC, heat and power, thermal systems design, and alternate energy systems courses are appropriate m-CHP topics. The types of material and level of analysis for this range of courses vary. In thermodynamics or heat transfer, basic problems involving a m-CHP flavor are needed, but in an alternate energy systems course much more detail and content would be required. This instructional module contains both lecture material and a compilation of problems/exercises for both m-CHP systems and components.
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Nijmeh, Salem Daud. "Solar chemical heat pumps for heating and cooling in Jordan." Thesis, University of Reading, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303147.
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Buker, Mahmut Sami. "Building integrated solar thermal collectors for heating & cooling applications." Thesis, University of Nottingham, 2015. http://eprints.nottingham.ac.uk/29009/.
Full textAbstract:
International Energy Agency Solar Heating & Cooling (IEA SHC) programme states the fact that space/water heating and cooling demand account for over 75% of the energy consumed in single and multi-family homes. Solar energy technology can meet up to 100% of this demand depending on the size of the system, storage capacity, the heat load and the region’s climate. Solar thermal collectors are particular type of heat extracting devices that convert solar radiation into thermal energy through a transport medium or flowing fluid. Although hybrid PV/T or thermal-alone systems offer some advantages to improve the solar heat utilisation, there are a few technical challenges found in these systems in practice that prevented wide-scale applications. These technical drawbacks include being expensive to make and install, inability of switching already-built photovoltaic (PV) systems into PV/T systems, architectural design etc. The aims of this project, therefore, were to investigate roof integrated solar thermal roof collectors that properly blend into surrounding thus avoiding ‘add on’ appearance and having a dual function (heat absorption and roofing). Another objective was to address the inherent technical pitfalls and practical limitations of conventional solar thermal collectors by bringing unique, inexpensive, maintenance free and easily adaptable solutions. Thus, in this innovative research, unique and simple building integrated solar thermal roof collectors have been developed for heating & cooling applications. The roof systems which mainly based on low cost and structurally unique polyethylene heat exchanger are relatively cost effective, competitive and developed by primarily exploiting components and techniques widely available on the market. The following objectives have been independently achieved via evaluating three aspects of investigations as following: • Investigation on the performance of poly heat exchanger underneath PV units • Investigation on the performance of a Building Integrated PV/T Roof ‘Invisible’ Collector combined with a liquid desiccant enhanced indirect evaporative cooling system • Investigation on the build-up and performance test of a novel ‘Sandwich’ solar thermal roof for heat pump operation These works have been assessed by means of computer simulation, laboratory and field experimental work and have been demonstrated adequately. The key findings from the study confirm the potential of the examined technology, and elucidate the specific conclusions for the practice of such systems. The analysis showed that water temperature within the poly heat exchanger loop underneath PV units could reach up to 36°C and the system would achieve up to 20.25% overall thermal efficiency. Techno-economic analysis was carried out by applying the Life Cycle Cost (LCC) method. Evaluations showed that the estimated annual energy savings of the overall system was 10.3 MWh/year and the cost of power generation was found to be £0.0622 per kWh. The heat exchanger loop was coupled with a liquid desiccant enhanced indirect evaporative cooling unit and experimental results indicated that the proposed system could supply about 3 kW of heating and 5.2 kW of cooling power. Lastly, the results from test of a novel solar thermal collector for heat pump operation presented that the difference in water temperature could reach up to 18°C while maximum thermal efficiency found to be 26%. Coefficient Performance of the heat pump (COPHP) and overall system (COPSYS) averages were attained as COPHP=3.01 and COPSYS=2.29, respectively. An economic analysis pointed a minimum payback period of about 3 years for the system.
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Mert, Cuce Ayse Pinar. "Innovative heating, cooling and ventilation technologies for low-carbon buildings." Thesis, University of Nottingham, 2016. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.716485.
Full textAbstract:
Sectoral energy consumption analyses clearly indicate that building sector plays a key role in global energy consumption, which is almost 40% in developed countries. Among the building services; conventional heating, ventilation and air conditioning (HVAC) systems have the greatest percentage in total energy consumption of buildings. According to the latest research, HVAC is responsible for around 40% of total building energy consumption and 16% of total global energy consumption. In this respect, decisive measures need to be taken to mitigate the energy consumption due to HVAC. The research carried out within the scope of this thesis covers innovative heating, cooling and ventilation technologies for low-carbon buildings. The novel technologies developed are introduced and investigated both theoretically and experimentally. The results indicate that optimised HVAC systems with waste heat recovery have a significant potential to mitigate energy consumed in buildings, thus to halt carbon emissions. Especially plate-type roof waste heat recovery units are very attractive for the said hybrid applications with a thermal efficiency greater than 88%. The said systems are also promising in terms of overall coefficient of performance (COP). The average COP of plate-type roof waste heat recovery unit is determined to be about 4.5, which is incomparable with those of conventional ventilation systems. Preheating performance of fresh air in winter season is found to be remarkable. Comprehensive in- situ tests clearly reveal that the temperature rise in fresh air is found to be around 7 °C. Plate-type roof waste heat recovery units also provide thermal comfort conditions for occupants. Indoor CCE concentration is observed to be varying from 350 to 400 ppm which is very appropriate in term of air quality. In addition, average relative humidity is found to be 57%, which is in the desired range according to the latest building standards. Desiccant-based evaporative cooling systems are capable of providing Abstract desired indoor environments for occupants as well as having considerably high COP ranges. An average of 5.3 °C reduction is achieved in supply air temperature by utilising those systems as well as having relative humidity distribution in thermal comfort range. The dehumidification effectiveness is found to be 63.7%, which is desirable and promising. The desiccant-based evaporative cooling system has a great potential to mitigate cooling demand of buildings not only in hot arid but also in temperate humid climates.
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Lindgren, Jonas. "Numerical modelling of district heating networks." Thesis, Umeå universitet, Institutionen för fysik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-143896.
Full textAbstract:
District heating is today, in Sweden, the most common method used for heating buildings in cities. More than half of all the buildings, both commercial and residential, are heated using district heating. The load on the district heating networks are affected by, among other things, the time of the day and different external conditions, such as temperature differences. One has to be able to simulate the heat and pressure losses in the network in order to deliver the amount of heat demanded by the customers. Expansions of district heating networks and disrupted pipes also demand good simulations of the networks. To cope with this, energy companies use simulation software. These software need to contain numerical methods that provide accurate and stable results and at the same time be fast and efficient. At the moment there are available software packages that works but these have some limitations. Among other things you may need to divide the whole network into smaller loops or try to guess how the distribution of pressure and flow in the network looks like. The development in recent years makes it possible to use better and more efficient algorithms for these types of problems. The purpose of this report is therefore to introduce a better and more efficient method than that used in the current situation. This work is the first step in order to replace a current method used in a simulation software provided by Vitec energy. Therefore, we will in this report, stick to computing pressure and flow in the network. The method we will introduce in this report is called the gradient method and it is based on the Newton Raphson method. Unlike with older methods like Hardy Cross which is a relaxation method, you do not have to divide the network into loops. Instead you create a matrix representation of the network that is used in the computations. The idea is also that you should not need to make good initial guesses to get the method to converge quickly. We performed a number of test simulations in order to examine how the method performs. We tested how different initial guesses and how different sizes of the networks affected the number of iterations. The results shows that the model is capable of solving large networks within a reasonable number of iterations. The results also show that the initial guesses have little impact on the number of iterations. Changing the initial guess on the pressure does not affect the number at all but it turns out that changing the initial guess on the flow can affect the number of iterations a little, but not much.
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Ryjkov, Vladimir Leonidovich. "Laser cooling and sympathetic cooling in a linear quadrupole rf trap." Texas A&M University, 2003. http://hdl.handle.net/1969.1/1637.
Full textAbstract:
An investigation of the sympathetic cooling
method for the studies of large ultra-cold molecular ions in a quadrupole ion trap has been conducted.Molecular dynamics simulations are performed to study the rf heating mechanisms in the ion trap. The dependence of
rf heating rates on the ion temperature, trapping parameters,
and the number of ions is obtained. New rf heating mechanism
affecting ultra-cold ion clouds exposed to laser radiation is described.The saturation spectroscopy setup of the hyperfine spectra
of the molecular iodine has been built to provide an accurate frequency reference for the laser wavelength. This reference is used to obtain the fluorescence lineshapes of
the laser cooled Mg$^+$ ions under different trapping conditions.The ion temperatures are deduced from the measurements, and
the influence of the rf heating rates on the fluorescence lineshapes
is also discussed. Cooling of the heavy ($m=720$a.u.) fullerene ions to under 10K by the means of the sympathetic cooling by the Mg$^+$ ions($m=24$a.u.) is demonstrated. The single-photon imaging system has been developed and used to obtain the images of the Mg$^+$ ion crystal structures at mK temperatures.
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Horák, Jakub. "Moderní bioplynová stanice jako součást „Smart Regions“." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2015. http://www.nusl.cz/ntk/nusl-232158.
Full textAbstract:
This thesis deals with the design of computational model of a biogas plant and its use in the concept of intelligent region with focusing on district heating and cooling network. The introduction contains review of technology used in the biogas plant. This review covers the description of modern biogas plants and determination of the energy and technology parameters for computational model of biogas plant. The next part of thesis describes analyze of the dynamics of the operation and the possibilities of using waste heat from biogas plant. The last and also the most important part is based on design of computational model of a biogas plant and design of connection of a biogas plant to the district heating and cooling network.
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Liu, Shuli. "A novel heat recovery/desiccant cooling system." Thesis, University of Nottingham, 2008. http://eprints.nottingham.ac.uk/11602/.
Full textAbstract:
The global air temperature has increased by 0.74± 0.18 °C since 1905 and scientists have shown that CO2 accounts for 55 percentages of the greenhouse gases. Global atmospheric CO2 has been sharply increased since 1751, however the trend has slowed down in last fifty years in the Western Europe. UK and EU countries have singed the Kyoto agreement to reduce their greenhouse gas emissions by a collective average of 12.5% below their 1990 levels by 2020. In the EU, 40% of CO2 emission comes from the residential energy consumption, in which the HVAC system accounts for 50%, lighting accounts for 15% and appliances 10%. Hence, reducing the fossil-fuel consumption in residential energy by utilizing renewable energy is an effective method to achieve the Kyoto target. However, in the UK renewable energy only accounts for 2% of the total energy consumption in 2005. A novel heat recovery/desiccant cooling system is driven by the solar collector and cooling tower to achieve low energy cooling with low CO2 emission. This system is novel in the following ways: • Uses cheap fibre materials as the air-to-air heat exchanger, dehumidifier and regenerator core • Heat/mass fibre exchanger saves both sensible and latent heat from the exhaust air • The dehumidifier core with hexagonal surface could be integrated with windcowls/catchers draught • Utilises low electrical energy and therefore low CO2 is released to the environment The cooling system consists of three main parts: heat/mass transfer exchanger, desiccant dehumidifier and regenerator. The fibre exchanger, dehumidifier and regenerator cores are the key parts of the technology. Owing to its proper pore size and porosity, fibre is selected out as the exchanger membrane to execute the heat/mass transfer process. Although the fibre is soft and difficult to keep the shape for long term running, its low price makes its frequent replacement feasible, which can counteract its disadvantages. A counter-flow air-to-air heat /mass exchanger was investigated and simulation and experimental results indicated that the fibre membranes soaked by desiccant solution showed the best heat and mass recovery effectiveness at about 89.59% and 78.09%, respectively. LiCl solution was selected as the working fluid in the dehumidifier and regenerator due to its advisable absorption capacity and low regeneration temperature. Numerical simulations and experimental testing were carried out to work out the optimal dehumidifier/regenerator structure, size and running conditions. Furthermore, the simulation results proved that the cooling tower was capable to service the required low temperature cooling water and the solar collector had the ability to offer the heating energy no lower than the regeneration temperature 60℃. The coefficient-of-performance of this novel heat recovery/desiccant cooling system is proved to be as high as 13.0, with a cooling capacity of 5.6kW when the system is powered by renewable energy. This case is under the pre-set conditions that the environment air temperature is 36℃ and relative humidity is 50% (cities such as Hong Kong, Taiwan, Spain and Thailand, etc). Hence, this system is very useful for a hot/humid climate with plenty of solar energy. The theoretical modelling consisted of four numerical models is proved by experiments to predict the performance of the system within acceptable errors. Economic analysis based on a case (200m2 working office in London) indicated that the novel heat recovery/desiccant cooling system could save 5134kWh energy as well as prevent 3123kg CO2 emission per year compared to the traditional HVAC system. Due to the flexible nature of the fibre, the capital and maintenance cost of the novel cooling system is higher than the traditional HVAC system, but its running cost are much lower than the latter. Hence, the novel heat recovery/desiccant cooling system is cost effective and environment friendly technology.
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Chen, Xiangjie. "Investigations of heat powered ejector cooling systems." Thesis, University of Nottingham, 2013. http://eprints.nottingham.ac.uk/29721/.
Full textAbstract:
In this thesis, heat powered ejector cooling systems was investigated in two ways: to store the cold energy with energy storage system and to utilize low grade energy to provide both electricity and cooling effect. A basic ejector prototype was constructed and tested in the laboratory. Water was selected as the working fluid due to its suitable physical properties, environmental friendly and economically available features. The computer simulations based on a 1-0 ejector model was carried out to investigate the effects of various working conditions on the ejector performance. The coefficients of performance from experimental results were above 0.25 for generator temperature of lI5°C-130 °C, showing good agreements with theoretical analysis. Experimental investigations on the operating characteristics of PCM cold storage system integrated with ejector cooling system were conducted. The experimental results demonstrated that the PCM cold storage combined with ejector cooling system was practically applicable. The effectiveness-NTU method was applied for characterizing the tube-in-container PCM storage system. The correlation of effectiveness as the function of mass flow rate was derived from experimental data, and was used as a design parameter for the PCM cold storage system. In order to explore the possibility of providing cooling effect and electricity simultaneously, various configurations of combined power and ejector cooling system were studied experimentally and theoretically. The thermal performance of the combined system in the range of 0.15-0.25 and the turbine output between 1200W -1400W were obtained under various heat source temperatures, turbine expansion ratios and condenser temperatures. Such combined system was further simulated with solar energy as driving force under Shanghai climates, achieving a predicted maximum thermal efficiency of 0.2. By using the methods of Life Saving Analysis, the optimized solar collector area was 30m2 and 90m2 respectively for the system without and with power generation. The environmental impacts and the carbon reductions of these two systems were discussed.
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Twort, Charles Tyler. "An exergy analysis of mine cooling systems." Thesis, University of Nottingham, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.323333.
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Mohamed, Y. "Interactive analysis of power station cooling systems." Thesis, University of Manchester, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.380600.
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Grüner, Florian. "Experiments and simulation of transverse cooling and heating in ion channeling." Diss., lmu, 2003. http://nbn-resolving.de/urn:nbn:de:bvb:19-16339.
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Petters, Jonathan L. Clothiaux Eugene. "The impact of radiative heating and cooling on marine stratocumulus dynamics." [University Park, Pa.] : Pennsylvania State University, 2009. http://etda.libraries.psu.edu/theses/approved/WorldWideIndex/ETD-4602/index.html.
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Gurjer, Yeshwant Ramesh. "Use of Heat Pumps for Heating and Night Cooling of Greenhouses." NCSU, 2001. http://www.lib.ncsu.edu/theses/available/etd-20011105-182143.
Full textAbstract:
Gurjer, Yeshwant Ramesh. Use of Heat Pumps for Heating and Night Cooling of Greenhouses. (under the direction of Daniel H. Willits). The use of heat pumps for heating and night cooling of greenhouses was investigated using a computer simulation program and weather data from Typical Meteorological Year (TMY2) datasets for Raleigh, NC, and Wilmington, NC. A greenhouse computer model taken from the literature, along with the heat pump subroutines (HPHEAT and HPCOOL) developed in this study, were used for the simulations. The use of heat pumps for heating only, and for heating plus night cooling, were examined separately using both standard and time-of-use electricity rates for two North Carolina utility providers. When heat pumps were used only for heating, standard electricity rates were predicted to provide greater savings in utility costs compared to time-of-use rates. When heat pumps were used for both heating and night cooling, the predicted savings in utility costs was greater for time-of-use electricity rates. Night cooling was predicted to decrease the average daily temperature (0.10C to 1.10C) and average nighttime temperature (0.10C to 2.00C) inside the greenhouse providing the potential for increased yield. Although a heat pump of capacity 36.5 W/m2 of floor area provided less savings in total costs compared to a capacity of 76 W/m2, the heat pump with the smaller capacity (36.5 W/m2) may be a better proposition because of the lower purchase cost.
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Hardy, John David. "A Cooling, Heating, and Power for Buildings (CHP-B) Instructional Module." MSSTATE, 2003. http://sun.library.msstate.edu/ETD-db/theses/available/etd-04082003-030901/.
Full textAbstract:
An emerging category of energy systems, consisting of power generation equipment coupled with thermally-activated components, has evolved as Cooling, Heating, and Power (CHP). The application of CHP systems to buildings has developed into a new paradigm ? Cooling, Heating, and Power for Buildings (CHP-B). This instructional module has been developed to introduce undergraduate engineering students to CHP-B. In the typical ME curriculum, a number of courses could contain topics related to CHP. Thermodynamics, heat transfer, thermal systems design, heat and power, alternate energy systems, and HVAC courses are appropriate for CHP topics. However, the types of material needed for this mix of courses vary. In thermodynamics, basic problems involving a CHP flavor are needed, but in an alternate energy systems course much more CHP detail and content would be required. This series of lectures on CHP-B contains both a stand-alone CHP treatment and a compilation of problems/exercises.
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Kizikoglu, Atahan Riza. "Thermo-Economic Analysis of Solar Cooling/Heating Systems for Mediterranean Climates." Thesis, KTH, Kraft- och värmeteknologi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-161065.
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This study focuses on the efficient use of solar energy for a certain region in the Mediterranean basin. Solar thermal energy becomes increasingly popular and the available solar market is investigated with the aim of selecting and assessing a pilot region for a promising solar application. The work herein focuses on estimating the potential of three different 100% solar-driven integrated systems to cover the entire cooling and heating demand of a selected single family house solely by solar energy. The three different alternative systems are presented and examined in detail for the actual case study application. The sample house within the chosen region is located on the south coast of Turkey. The entire thermal demand of this house for both cooling during summer and heating during winter has first been properly calculated. Characteristic features of the house and the typical design parameters for the region have been analyzed, as well as and their daily and annual variations. Heat loss and heating/cooling load calculations have been done with respect to these specifications and to ASHRAE regulations. After finding the building`s demands for the comfort temperature, the three different solar-driven systems are simulated for a practical application to the sample house. Required mechanical equipment and parasitic load consumption has been investigated for each system and investment cost analyses have been performed respectively. Simplified payback times for each alternative system are calculated and discussed. Payback period sensitivity analysis was attempted for two different locations featuring different grid pricing regulations. As a conclusion, feasibility analysis for the three examined types of solar-driven integrated heating and cooling systems has been attempted, which gives a good representation of the potential solar energy market in the Mediterranean region. Also some suggestions are offered to the companies which develop and market solar heating/cooling systems.
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CAMPOS, SERGIO LIBANIO DE. "DEVELOPMENT OF AN AUTOMOTIVE AIR CONDITIONING SYSTEM FOR HEATING AND COOLING." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2014. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=24641@1.
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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROSistemas condicionadores de ar automotivos têm sido extensivamente estudados, buscando melhor eficiência de resfriamento e redução do consumo de combustível. O presente trabalho tem como objetivo o estudo de um sistema condicionador de ar automotivo operando nos modos de resfriamento e aquecimento, este último atendendo às necessidades de conforto em dias frios nos veículos elétricos, os quais não apresentam calor de rejeito do motor, como nos veículos convencionais. Para tal foi projetado e montado, no Laboratório de Refrigeração, Condicionamento de Ar e Criogenia da PUC-Rio, um aparato experimental composto por duas câmaras de temperatura e umidade controladas, uma simulando o compartimento de passageiros e a outra, o ambiente externo. Um típico sistema condicionador de ar automotivo, composto por componentes comercialmente disponíveis e utilizados nos veículos atuais, foi dotado de válvulas direcionais, permitindo a inversão do ciclo de compressão de vapor do modo de resfriamento para o modo de aquecimento, operando neste último como bomba de calor. Dados experimentais foram levantados sob operação em regime permanente e transiente (período de partida), com temperaturas entre – 5 graus Celcius e 45 graus Celcius. Para o modo de resfriamento, seguiu-se a norma SAE J2765 e, para o de aquecimento, na ausência de normas, foram cobertas as operações em modos de recirculação do ar da cabine e de renovação com ar externo, entre as temperaturas de -5 graus Celcius e 10 graus Celcius. Foi também realizada uma simulação numérica, validada pelos dados experimentais, utilizando as equações fundamentais da termodinâmica e transferência de calor. O sistema testado mostrou-se viável na aplicação em veículos elétricos, uma vez que nestes o calor de rejeito previsto (regeneração de frenagem e efeito Joule na eletrônica de potência) não é suficiente para o conforto térmico em dias frios. Demonstrou-se que a bomba de calor consome menos energia que resistências as elétricas atualmente utilizadas.
Automotive air conditioning systems have been extensively studied, searching for better cooling efficiency and reduced fuel consumption. The present work aims to study a system of automotive air conditioner operating in cooling and heating modes, the latter satisfies the needs of comfort on cold days in electrical vehicles, which do not include waste heat from the engine as the conventional vehicles. To this was designed and assembled in the Refrigeration, Air Conditioning and Cryogenics Laboratory, in Puc-Rio, an experimental apparatus consists of two chambers with temperature and humidity controlled, one, simulating the passenger compartment and the other, the external environment. A typical automotive air conditioning system, composed of commercially available components used in current vehicles is provided with a directional valve, allowing the inversion of vapor compression cooling mode to the heating mode cycle, the latter operating as a heat pump.
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Boufadel, George Fadlo. "Dynamic thermal response of buildings resulting from heating and cooling interruptions." Diss., Virginia Polytechnic Institute and State University, 1987. http://hdl.handle.net/10919/74757.
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Transient modelling of heat fluxes and temperatures in structures was conducted to examine the effect of various characteristics on the temperature response during unusual operating and extreme weather conditions. The analytical model was validated using published experimental data and numerical results from well-known computer codes.
The effect of including radiation heat transfer between interior surfaces, using the Mean Radiative Temperature method, on the temperature response was investigated and found to be negligible for a typical commercial building and a house during winter and summer power outages.
The effect of thermal mass in the interior and exterior walls on the inside temperature drift after an HVAC system cutoff or a power outage was presented. The inside air temperature response curve is presented for different wall (exterior or interior) constructions of buildings. The effect of insulation position in exterior walls was also shown for several R values. The effect of exterior wall emissivity, sky temperature, outside vertical convective coefficient, furnishings, and ground temperature on the interior temperature response during winter and summer power outages were examined for buildings.
The effect of infiltration on the temperature drift in buildings was investigated during winter and summer power outages. Restarting the HVAC after the power outage was examined during both seasons for typical buildings.
Outside temperature profiles exceeding the 97.5 design temperature criterion were used to study the effect of extreme weather on the interior temperature of buildings with the HVAC system operating.Ph. D.
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Chou, Lu-chien. "Drag reducing cationic surfactant solutions for district heating and cooling systems /." The Ohio State University, 1991. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487758178238587.
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Edge, Jerry. "Passive flow monitoring in heating system networks." Thesis, Northumbria University, 2001. http://nrl.northumbria.ac.uk/600/.
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This work deals with a "passive flow monitoring" technique which can be used to help determine the energy used by a building's heating system. The thesis first highlights the background and importance of energy monitoring in buildings. This work points out that energy monitoring is an important feature in the running of buildings today. In the past, the energy crisis in the 1970's made people aware of how important it was to have knowledge of how buildings consume energy. More recently, environmental issues have reinforced the importance of gaining good quality information on energy use in buildings. This thesis investigates the use of combined port flow characteristics/control signal relationships for three port control valves to predict system water flow rate in heating systems. A laboratory test rig was built and a range of three port valves were tested. A series of combined port flow characteristics/control signal relationships were developed from measurements from the test rig. Curve fit models were then applied to these relationships in the form of polynomial equations. Where practical relationships could not be measured for a valve, a theoretical valve model was derived. In order to validate the polynomial regression model and the mathematical model, the test rig was modified to take into account practical heating system characteristics. A series of flow characteristic results were produced from the modified test rig so that the performance of the two models (empirical and mathematical) could be evaluated. It was found that the empirical model performed well in predicting combined port flow ratios with RMS errors ranging between 2.73% and 6.54%. The mathematical model gave overall prediction errors between -2.63% and +9.25% which compare favourably with the performance of some flow meters. The work then goes on to present an energy use algorithm which incorporates the valve model (empirical or theoretical) for use in BEMS.
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Jerome, David. "Building load analysis and graphical display as a design tool." Thesis, Georgia Institute of Technology, 1997. http://hdl.handle.net/1853/16410.
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Cleaveland, John P. "Loadcal : a microcomputer simulation for estimating heating and cooling loads for commercial buildings." Thesis, Georgia Institute of Technology, 1985. http://hdl.handle.net/1853/23099.
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Kilpatrick, Yvonne Younis. "Daylighting and high efficiency lighting : the effects on heating and cooling loads." Thesis, Georgia Institute of Technology, 1986. http://hdl.handle.net/1853/21810.
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Gatts, Timothy J. "Investigation of the heating and cooling of composite glass seals for SOFCs." Connect to resource, 2008. http://hdl.handle.net/1811/32060.
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Terblanche, Johann Pierre. "Design and performance evaluation of a HYDROSOL space heating and cooling system." Thesis, Stellenbosch : Stellenbosch University, 2015. http://hdl.handle.net/10019.1/97095.
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Thesis (MEng)--Stellenbosch University, 2015.ENGLISH ABSTRACT: Space heating and cooling, as required for chicken poultry farming, is an energy intensive operation. Due to the continuous rise in the prices of fossil fuel, water and electricity, there is a need to develop renewable and sustainable energy systems that minimise the use of fuel or electricity, for heating, and water, for cooling of air. The HYDROSOL (HYDro ROck SOLar) system, developed at Stellenbosch University, is such a renewable energy system that potentially provides a low cost solution. Instead of using conventional gas and electricity heaters for the heating of air during winter, the HYDROSOL system collects solar heat, stores it in a packed bed of rocks and dispatches the heat as required. During hot summer days, when cooling is needed, the rocks are cooled during the night when the ambient temperatures are low and/ or by evaporative cooling by spraying water onto them. During the day, hot air is then cooled when it passes through the colder rocks with minimal water consumption compared to current systems. In this thesis, a prototype of the HYDROSOL system is presented, designed and built for experimental testing. A transient 2-D thermo flow model is developed and presented for the analytical and experimental performance evaluation of this system for solar heating and night air cooling operation. This model is used to conduct a parametric study on HYDROSOL to gain a better understanding of the operation and control of the system. The HYDROSOL concept is intended to be used for heating and cooling of residential buildings, office suites, warehouses, shopping centres, food processing industries e.g. drying of foods, and various agricultural industries e.g. greenhouses. In this thesis, a HYDROSOL system is developed mainly for poultry broiler houses in South Africa focussing on convective dry cooling, charging the rock bed with night-time ambient air, and convective heating, harvesting solar heat during the day, with different modes of operation available.
AFRIKAANSE OPSOMMING: Ruimte verhitting en verkoeling, soos benodig vir hoender pluimvee boerdery, is ‘n energie intensiewe bedryf. As gevolg van die voortdurende styging in fossiel brandstof-, water- en elektrisiteitpryse, het ‘n behoefte ontstaan om hernubare en volhoubare energie-stelsels te ontwikkel wat minder brandstof of elektrisiteit, vir verhitting, en water, vir verkoeling van lug, gebruik. Die HYDROSOL (HYDro ROck SOLar) stelsel, wat ontwikkel is by die Universiteit van Stellenbosch, is ‘n hernubare energie-stelsel wat ‘n potensiële lae koste oplossing bied. In plaas daarvan om konvensionele gas en elektrisiteit verwarmers vir verhitting van lug gedurende die winter te gebruik, maak HYDROSOL gebruik van son warmte, stoor dit in `n gepakte bed van klip en onttrek die warmte soos benodig. Gedurende die warm somer dae wanneer verkoeling benodig word, word die klippe gedurende die nag, met kouer omgewings lug en/of met verdampingsverkoeling, deur water op die klippe te spuit, afgekoel. Gedurende die dag word warm lug afgekoel deur die lug oor die koue klippe te forseer met minimale waterverbruik in vergelyking met huidige stelsels. ‘n Prototipe van die HYDROSOL word voorgestel, ontwerp en gebou vir eksperimentele doeleindes. ‘n 2-D tyd afhanklike termo- vloei model word voorgestel vir die analitiese en eksperimentele verrigting evaluering vir son verhitting en nag lug verkoeling. Hierdie model word gebruik om ‘n parametriese studie te doen om die werking en beheer van HYDROSOL beter te verstaan. Die HYDROSOL stelsel is bedoel om die verwarming en verkoeling vereistes van residensiële geboue, kantoor areas, pakhuise, winkelsentrums, voedsel verwerking nywerhede, soos bv. die droging van voedsel, en verskeie landboubedrywe, soos bv. kweekhuise, te bevredig. In hierdie tesis word ‘n HYDROSOL stelsel, hoofsaaklik vir pluimvee kuikenhuise in Suid- Afrika, ondersoek en fokus op die droë verkoeling, deur die rotsbed te laai gedurende die nag, asook droë- verhitting, wat gebruik maak van son energie gedurende die dag en kan beheer word op verskillende maniere.
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Vacenovský, Jan. "Návrh zařízení pro úpravu mikroklimatu v rekonstruovaném rodinném domě." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2018. http://www.nusl.cz/ntk/nusl-378499.
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This work is devoted to the design of a microclimate facility in a family house. The first part contains analysis of thermal losses before and after using thermal insulation. Based on this analysis, a heating system is proposed, including the necessary technical calculations for the operation of the system. As a heat source, a condensing boiler is selected. At the next point, the thesis focuses on the calculation of the heat gains in selected rooms in order to design a cooling device. A multisplit system is selected for cooling the rooms. In the next part the thesis deals with the design of forced ventilation of selected rooms. The ventilation system provides the necessary air exchange and covers heat losses through ventilation. At the end of the thesis is outlined the concept of regulation of individual systems and also the requirements for individual professions are described.
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Guillem, Reig Santiago. "Simulation of moisture alarm for district heating networks." Thesis, Högskolan i Gävle, Avdelningen för bygg- energi- och miljöteknik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-17466.
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Abohorlu, Doğramacı Pervin. "Investigation of novel evaporative cooling material for Cyprus climate." Thesis, University of Nottingham, 2018. http://eprints.nottingham.ac.uk/53245/.
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Energy consumption by human enhanced activities has led to distinctive environmental problems; in particular, climate change and global warming. In hot regions, the main reason for energy consumption comes from the cooling of many buildings. The intensity and duration of the sunshine in hot regions have a direct relation with the usage of cooling systems. The energy used for cooling purpose is continuously increasing and expected to increase in the following years. Evaporative cooling is one of the passive cooling method which has been used throughout history. As it is cheaper, environmentally-friendly and simpler compared to vapour compression systems, it is more widely used in residential, commercial and industrial buildings in hot and dry regions. Since this method is less efficient and limited under hot and humid climate, the desiccant based evaporative cooling system is preferred in such areas in order to dehumidify the air. The pad material used for evaporative cooling system is important as it helps to evaporate the water. Therefore, the material should be porous enough to absorb water which enhances the rate of evaporation. Moreover, the material should be available and cheap. This study shows the potential of using different materials for evaporative cooling systems. The aim of this study is to investigate the feasibility, suitability and potential of using local materials such as eucalyptus fibres, as cooling pads for evaporative cooling system in hot and dry regions. In addition to this, the liquid desiccant evaporative cooling systems by using potassium formate is also studied for hot and humid areas in Cyprus. Since Cyprus has multi-climate regions due to the topography and different weather condition, different cooling systems can be used for each region. The results are reported in terms of temperature difference, cooling output, COP, etc. The wind tunnel is used to test the eucalyptus fibres with an inlet air temperature of 35 °C to simulate the climate in Cyprus. It was found that the maximum reduction of air temperature was between 11.3 °C and 6.6 °C, while the maximum cooling efficiency was in the range of 71% and 49% at 0.1 and 0.6 m/s air velocity respectively. Corresponding cooling capacities were also calculated as 108 and 409 W indicating a directly proportional relation between air velocities and cooling performance. Following this, the conceptual design ideas of integrated eucalyptus fibres based evaporative cooling panel (EFECP) into building elements are considered to meet the demand for cooling and the architectural requirements of the building. These design ideas were developed for shutter, fenestration, toplighting elements, wind catcher-solar chimney and wall design of the building. The cooling performances of the hollow fibre integrated by using potassium formate desiccant based evaporative cooling system were experimentally investigated under the incoming air temperature in the range of 35 ˚C to 40 ˚C. The cooling capacity is increased as the air velocity is increased. At 3.5m/s, the cooling capacity is 1340 W, 1530 W and 1920 W respectively for incoming air relative humidity of 60%, 65% and 70%. Both evaporative cooling systems performances are discussed and clearly presented in this study. From the experimental testing in this thesis, it is concluded that local eucalyptus fibres can be used for hot-dry areas and liquid desiccant evaporative cooling systems can be used for hot-humid areas of Cyprus. Since using of eucalyptus fibres for evaporative cooling system is locally available, simple construction and easy to apply, the design ideas for integrating eucalyptus fibres with evaporative cooling system are developed within the scope of the thesis. The usage of local eucalyptus fibres and Polyvinylidene fluoride (PVDF) hollow fibres as evaporative cooling pad, the evaporative cooling process designed by using fibres and the conceptual building design ideas integrated local eucalyptus fibres combined with evaporative cooling system are all the novel ideas of this thesis.
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Aboul, Naga Mohsen M. "Natural ventilation and cooling by evaporation in hot-arid climates." Thesis, University of Leeds, 1990. http://etheses.whiterose.ac.uk/4043/.
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In hot climates, outside air is too hot during the day. In hot arid climates, low humidity increases discomfort. For comfort, hot air should be cooled before flowing into dwellings and moisture in the moving air increased. For the poor, comfort must be sought cheaply. In places without electricity only 'natural' ventilation is feasible. The air temperature difference between the sunny and the shaded side of a building can be exploited to promote ventilation. Ventilation cooling can be enhanced with an 'evaporative cooling cavity' attached to a dwelling on its shaded side. The cavity has a top external inlet and a bottom internal outlet, and incorporates one or two wet partitions. The air within the cavity, being moist. descends. drawing the outside warm and dry air into the cavity. Evaporation cools the air and raises its humidity. The cool incoming air will reduce inside air temperature and improve comfort. The performance of a typical cavity to induce cooling ventilation by evaporation was investigated theoretically and experimentally with a full scale model. The temperature drop. velocity and relative humidity of the air were measured. The pattern of the air flow in the cavity was observed. The optimum dimensions of the cavity were established. Buoyancy air flow and fan-assisted air flow were analysed in the steady state. Since a convective heat transfer coefficient for air flowing between two parallel vertical surfaces was not found in the literature, appropriate convective heat and surface mass transfer coefficients were derived from measurements. The results show the convective heat transfer coefficient to be independent of the separation of the wet surfaces, and that with separation greater than 3Omm, each wet surface behaves as a 'free' surface. The optimum separation between wet surfaces was assessed, and the water removed by evaporation was determined, and found to be small. The Admittance Method was used to assess comfort. Ventilation and evaporation effectiveness were evaluated. An outlet air velocity of O.3m/s accompanied with a temperature drop of about 6K was achieved. Design proposals for hot arid climates are offered.