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Truong, Nguyen Le, Leif Gustavsson y Ambrose Dodoo. "Heat Supply of Multi-apartment Buildings with Varied Heat Demands". Energy Procedia 61 (2014): 1464–67. http://dx.doi.org/10.1016/j.egypro.2014.12.148.
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Knudsen, Brage Rugstad, Hanne Kauko y Trond Andresen. "An Optimal-Control Scheme for Coordinated Surplus-Heat Exchange in Industry Clusters". Energies 12, n.º 10 (16 de mayo de 2019): 1877. http://dx.doi.org/10.3390/en12101877.
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Industrial plants organized in clusters may improve their economics and energy efficiency by exchanging and utilizing surplus heat. However, integrating inherently dynamic processes and highly time-varying surplus-heat supplies and demands is challenging. To this end, a structured optimization and control framework may significantly improve inter-plant surplus-heat valorization. We present a Modelica-based systems model and optimal-control scheme for surplus-heat exchange in industrial clusters. An industry-cluster operator is assumed to coordinate and control the surplus-heat exchange infrastructure and responsible for handling the surplus heat and satisfy the sink plants’ heat demands. As a case study, we use an industry cluster consisting of two plants with surplus heat available and two plants with heat demand. The total surplus heat and heat demand are equal, but the availability and demand are highly asynchronous. By optimally utilizing demand predictions and a thermal energy storage (TES) unit, the operator is able to supply more than 98% of the deficit heat as surplus heat from the plants in the industry cluster, while only 77% in a corresponding case without TES. We argue that the proposed framework and case study illustrates a direction for increasing inter-plant surplus-heat utilization in industry clusters with reduced use of peak heating, often associated with high costs or emissions.
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Peakman, Aiden y Bruno Merk. "The Role of Nuclear Power in Meeting Current and Future Industrial Process Heat Demands". Energies 12, n.º 19 (25 de septiembre de 2019): 3664. http://dx.doi.org/10.3390/en12193664.
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There is growing interest in the use of advanced reactor systems for powering industrial processes which could significantly help to reduce CO 2 emissions in the global energy system. However, there has been limited consideration into the role nuclear power would play in meeting current and future industry heat demand, especially with respect to the advantages and disadvantages nuclear power offers relative to other competing low-carbon technologies, such as Carbon Capture and Storage (CCS). In this study, the current market needs for high temperature heat are considered based on UK industry requirements and work carried out in other studies regarding how industrial demand could change in the future. How these heat demands could be met via different nuclear reactor systems is also presented. Using this information, it was found that the industrial heat demands for temperature in the range of 500 ∘ C to 1000 ∘ C are relatively low. Whilst High Temperature Gas-cooled Reactors (HTGRs), Very High Temperature Reactors (VHTRs), Gas-cooled Fast Reactors (GFRs) and Molten Salt Reactors (MSRs) have an advantage in terms of capability to achieve higher temperatures (>500 ∘ C), their relative benefit over Liquid Metal-cooled Fast Reactors (LMFRs) and Light Water Reactors (LWRs) is actually smaller than previous studies indicate. This is because, as is shown here, major parts of the heat demand could be served by almost all reactor types. Alternative (non-nuclear) means to meet industrial heat demands and the indirect application of nuclear power, in particular via producing hydrogen, are also considered. As hydrogen is a relatively poor energy carrier, current trends indicate that the use of low-carbon derived hydrogen is likely to be limited to certain applications and there is a focus in this study on the emerging demands for hydrogen.
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Peakman, Aiden y Robert Gregg. "The Fuel Cycle Implications of Nuclear Process Heat". Energies 13, n.º 22 (20 de noviembre de 2020): 6073. http://dx.doi.org/10.3390/en13226073.
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International and UK fuel cycle scenario analyses performed to date have focused on nuclear plants producing electricity without considering in detail the other potential drivers for nuclear power, such as industrial process heat. Part of the reason behind the restricted applications of nuclear power is because the assumptions behind the future scenario are not fully captured, for example how big are demands from different sectors? Here we present a means to fully capture the potential opportunities for nuclear power using Sankey diagrams and then, using this information, consider for the first time in the UK the fuel cycle implications of decarbonising industrial heat demand in the year 2050 with nuclear power using the ORION fuel cycle code to study attributes related to spent fuel, uranium demand and decay heat from the spent fuel. We show that even in high industrial energy demand scenarios, the sensitivity of spent fuel masses and decay heat to the types of reactor deployed is relatively small compared to the greater fuel cycle demands from large-scale deployment of nuclear plants for electricity production. However, the sensitivity of spent fuel volumes depends heavily on the extent to which High Temperature Reactor and Light Water Reactor systems operating on a once-through cycle are deployed.
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Truong, Nguyen Le, Ambrose Dodoo y Leif Gustavsson. "Renewable-based heat supply of multi-apartment buildings with varied heat demands". Energy 93 (diciembre de 2015): 1053–62. http://dx.doi.org/10.1016/j.energy.2015.09.087.
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Kauko, Hanne, Daniel Rohde y Armin Hafner. "Local Heating Networks with Waste Heat Utilization: Low or Medium Temperature Supply?" Energies 13, n.º 4 (20 de febrero de 2020): 954. http://dx.doi.org/10.3390/en13040954.
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District heating enables an economical use of energy sources that would otherwise be wasted to cover the heating demands of buildings in urban areas. For efficient utilization of local waste heat and renewable heat sources, low distribution temperatures are of crucial importance. This study evaluates a local heating network being planned for a new building area in Trondheim, Norway, with waste heat available from a nearby ice skating rink. Two alternative supply temperature levels have been evaluated with dynamic simulations: low temperature (40 °C), with direct utilization of waste heat and decentralized domestic hot water (DHW) production using heat pumps; and medium temperature (70 °C), applying a centralized heat pump to lift the temperature of the waste heat. The local network will be connected to the primary district heating network to cover the remaining heat demand. The simulation results show that with a medium temperature supply, the peak power demand is up to three times higher than with a low temperature supply. This results from the fact that the centralized heat pump lifts the temperature for the entire network, including space and DHW heating demands. With a low temperature supply, heat pumps are applied only for DHW production, which enables a low and even electricity demand. On the other hand, with a low temperature supply, the district heating demand is high in the wintertime, in particular if the waste heat temperature is low. The choice of a suitable supply temperature level for a local heating network is hence strongly dependent on the temperature of the available waste heat, but also on the costs and emissions related to the production of district heating and electricity in the different seasons.
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Niemierka, Elżbieta y Piotr Jadwiszczak. "Cross-building cooling-to-heating energy transfer". E3S Web of Conferences 100 (2019): 00056. http://dx.doi.org/10.1051/e3sconf/201910000056.
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Nowadays office buildings are faced with high and long-term cooling demand with grate heat recovery potential. In low heating demand office buildings not all of recoverable excess heat can be utilised, so it forces to search the consumers beyond the energetic boundary of office building. One of more promising way is supplying residential building by excess heat to meet the space heating and domestic hot water demands. Proposed cross-building cooling-to-heating energy flow allows transferring and utilizing excess heat from office building in residential as a useful heat. This solution creates the flexible and sustainable environment and meets the energy challenges of the future, in line with current energy trends and policy.
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McKinley, Michael J., Davide Martelli, Glenn L. Pennington, David Trevaks y Robin M. McAllen. "Integrating Competing Demands of Osmoregulatory and Thermoregulatory Homeostasis". Physiology 33, n.º 3 (1 de mayo de 2018): 170–81. http://dx.doi.org/10.1152/physiol.00037.2017.
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Mammals are characterized by a stable core body temperature. When maintenance of core temperature is challenged by ambient or internal heat loads, mammals increase blood flow to the skin, sweat and/or pant, or salivate. These thermoregulatory responses enable evaporative cooling at moist surfaces to dissipate body heat. If water losses incurred during evaporative cooling are not replaced, body fluid homeostasis is challenged. This article reviews the way mammals balance thermoregulation and osmoregulation.
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Siddiqui, Salman, Mark Barrett y John Macadam. "A High Resolution Spatiotemporal Urban Heat Load Model for GB". Energies 14, n.º 14 (6 de julio de 2021): 4078. http://dx.doi.org/10.3390/en14144078.
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The decarbonisation of heating in the United Kingdom is likely to entail both the mass adoption of heat pumps and widespread development of district heating infrastructure. Estimation of the spatially disaggregated heat demand is needed for both electrical distribution network with electrified heating and for the development of district heating. The temporal variation of heat demand is important when considering the operation of district heating, thermal energy storage and electrical grid storage. The difference between the national and urban heat demands profiles will vary due to the type and occupancy of buildings leading to temporal variations which have not been widely surveyed. This paper develops a high-resolution spatiotemporal heat load model for Great Britain (GB: England, Scotland a Wales) by identifying the appropriate datasets, archetype segmentation and characterisation for the domestic and nondomestic building stock. This is applied to a thermal model and calibrated on the local scale using gas consumption statistics. The annual GB heat demand was in close agreement with other estimates and the peak demand was 219 GWth. The urban heat demand was found to have a lower peak to trough ratio than the average national demand profile. This will have important implications for the uptake of heating technologies and design of district heating.
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Ha, Sungkyun, Sungho Tae y Rakhyun Kim. "Energy Demand Forecast Models for Commercil Buildings in South Korea". Energies 12, n.º 12 (17 de junio de 2019): 2313. http://dx.doi.org/10.3390/en12122313.
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With the Paris Agreement entering into full force, South Korea must submit its target greenhouse gas emissions for commercial buildings by 2030 to the United Nations Framework Convention on Climate Change. To determine this target, the annual energy demands must be forecasted through appropriate models; the development of these models is the focus of our study. We developed a system to calculate energy demand forecasts by searching for suitable methods. We built distinct energy forecast models for petroleum, city gas, electricity, heat, and renewable energies. The results show that the most appropriate variable for the petroleum energy model is energy trend. Moreover, the annual increase rate of petroleum energy demand from 2019 to 2030 was forecasted to be −1.7%. The appropriate variable for city gas energy model was the floor area of commercial buildings, which was forecasted to increase at an annual average growth rate of 0.4% from 2019 to 2030. According to the forecast results of energy demand from 2019 to 2030, the annual average growth rates of electricity, heat, and renewable energy demands were 2.1%, −0.2%, and 1.3%, respectively.
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Čiuprinskas, Kęstutis y Vytautas Martinaitis. "CORRECTION OF A DESIGNED BUILDING'S HEAT BALANCE ACCORDING TO ITS REAL HEAT CONSUMPTION". JOURNAL OF CIVIL ENGINEERING AND MANAGEMENT 9, n.º 2 (30 de junio de 2003): 98–103. http://dx.doi.org/10.3846/13923730.2003.10531311.
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One of the most important issues in the implementation of energy saving measures is a proper evaluation of possible energy savings. If energy savings are overestimated in an energy audit (EA), a situation may occur where after the renovation, the implemented energy saving measures is not paid back or their pay back time is longer than expected before the funds (mostly loaned) were invested. To avoid such a situation, the procedure of a building's energy audit should involve the correction of calculated heat balance according to its real heat consumption, recalculated to the nonnative conditions. In manipulating different building parameters of not exact meanings, it is necessary to attain that the building's heat demand before renovation (theoretically calculated by the same methodology and parameters as demand after renovation) would be as close as possible to the actual heat consumption, recalculated under normative conditions. Only after such a fitting of the actual and theoretical heat demands (decomposition of building heat balance and correction of its components) is it possible to have a reasonable assessment of the feasible heat savings, after the implementation of heat saving measures. The aim of this work is to disclose some peculiarities of building heat balance that is used for energy audit calculations of existing buildings, to offer a calculation methodology evaluating these peculiarities, to show evidently the importance of the investigated problem.
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Fennell, Catherine. "‘Project heat’ and sensory politics in redeveloping Chicago public housing". Ethnography 12, n.º 1 (marzo de 2011): 40–64. http://dx.doi.org/10.1177/1466138110387221.
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This article examines Chicago’s ongoing public housing reforms and more broadly, welfare reform, as a kind of sensory politics. I analyze experiences of home heating at a redeveloping public housing project to establish how neoliberal demands for self-responsibility have become tied to demands that transitioning residents reconfigure their subjective senses of comfort. These twin demands have distributed the risks of transitioning out of public housing across an individual’s understanding of personal security as well as her obligations to kin. I show how approaching welfare reform as a sensory politics illuminates the emerging conditions of political recognition available to Chicago public housing residents as their longstanding representational bodies face obsolescence. Moreover, I argue that this approach invites us to reconsider theories of contestation and survival within urban poor people’s social movements.
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Hirogaki, Toshiki, Eiichi Aoyama, Keiji Ogawa, Sachiko Ogawa, Rie Okamoto y Ryosuke Oda. "High Efficiency and Eco-Friendly Heat Treatment of Small Parts with a Low-Power Diode Laser Beam". Key Engineering Materials 523-524 (noviembre de 2012): 232–37. http://dx.doi.org/10.4028/www.scientific.net/kem.523-524.232.
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Demand is increasing for the manufacturing and machining of small mechanical parts. We focus on using a multi-functional desktop-sized machine tool to meet such demands because power consumption is decreased when they are machined. However, few reports have focused on heat treatment among manufacturing processes, we investigate the laser heat treatment of small parts as a highly efficient and eco-friendly method and propose in-situ heat treatment on a desktop-sized machine tool using a low-power diode laser beam. We quenched a small thin steel plate with a 30 W diode laser source. Our proposed method makes it feasible to quench a small thin steel plate and effectively reduces the power consumption of in-situ heat treatment by a desktop-sized machine tool.
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Wheatcroft, Edward, Henry P. Wynn, Victoria Volodina, Chris J. Dent y Kristina Lygnerud. "Model-Based Contract Design for Low Energy Waste Heat Contracts: The Route to Pricing". Energies 14, n.º 12 (17 de junio de 2021): 3614. http://dx.doi.org/10.3390/en14123614.
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Urban Waste Heat Recovery, heat recovery from low-temperature urban sources such as data centres and metro systems, has a great deal of potential in terms of meeting domestic and commercial heat demands whilst significantly reducing carbon emissions. Urban sources of heat are advantageous in that they tend to be close to areas of high heat demand and are therefore highly suitable as inputs to existing and newly constructed district heating networks. This paper has two main focuses. Firstly, the issue of efficiency in waste heat recovery is addressed with a focus on Technical, Economic, Social, and Environmental (TESE) efficiencies, which we consider should be given equal consideration. Secondly, we address the question of contractual efficiency and argue that contracts should be underpinned by mathematical modelling. We then focus on the contractual relationship between the owner of the waste heat and the district heating operator and consider the question of waste heat pricing. We suggest a profit sharing approach in which the price per unit of waste heat is allowed to vary according to important aspects such as demand and the electricity price. A demonstration of this approach is presented using a simple model of a waste heat recovery system that extracts heat from a data centre in Brunswick, Germany.
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Qi, Zi Shu, Qing Gao, Yan Liu, Y. Y. Yan y Jeffrey D. Spitler. "Analysis and Research on the Performance of the Ground Source Heat Pump System in Different Areas of China". Applied Mechanics and Materials 148-149 (diciembre de 2011): 1137–40. http://dx.doi.org/10.4028/www.scientific.net/amm.148-149.1137.
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In the paper, it is to describe the performance of the vertical ground heat exchangers (GHE) in different areas of China. The energy consumption of ground source heat pump (GSHP) system is based on the instantaneous fluid temperature at the heat pump inlet. This temperature defines the GSHP coefficient of performance and hence the electricity consumption required in order to fulfill the energy demands of the building. A mathematical model for simulation of vertical ground heat exchanger system is built based on long time-step theory. The design methodology is based on a simulation that predicts the temperature response of the ground heat exchanger to hourly heating and cooling loads demand in 20 years. This paper presents GSHP system can achieve energy performance in buildings that heating and cooling loads all the year round in different areas.
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Skalík, Lukáš y Otília Lulkovičová. "A Software Optimization of the Solar Energy System Performance". Advanced Materials Research 899 (febrero de 2014): 199–204. http://dx.doi.org/10.4028/www.scientific.net/amr.899.199.
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The energy demand of buildings represents in the balance of heat use and heat consumption of energy complex in the Slovak national economy second largest savings potential. Their complex energy demands is the sum of total investment input to ensure thermal protection and annual operational demands of particular energy systems during their lifetime in building. The application of energy systems based on thermal solar systems reduces energy consumption and operating costs of building for support heating and domestic hot water as well as savings of non-renewable fossil fuels. Correctly designed solar energy system depends on many characteristics, i. e. appropriate solar collector area and tank volume, collector tilt and orientation as well as quality of used components. The evaluation of thermal solar system components by calculation software shows how can be the original thermal solar system improved by means of performance. The system performance can be improved of more than 31 % than in given system by changing four thermal solar system parameters such as heat loss coefficient and aperture area of used solar collector, storage tank volume and its height and diameter ratio.
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Chicherin, Stanislav y Amjad Anvari-Moghaddam. "Adjusting heat demands using the operational data of district heating systems". Energy 235 (noviembre de 2021): 121368. http://dx.doi.org/10.1016/j.energy.2021.121368.
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Mancic, Marko, Dragoljub Zivkovic, Pedja Milosavljevic y Milena Todorovic. "Mathematical modelling and simulation of the thermal performance of a solar heated indoor swimming pool". Thermal Science 18, n.º 3 (2014): 999–1010. http://dx.doi.org/10.2298/tsci1403999m.
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Buildings with indoor swimming pools have a large energy footprint. The source of major energy loss is the swimming pool hall where air humidity is increased by evaporation from the pool water surface. This increases energy consumption for heating and ventilation of the pool hall, fresh water supply loss and heat demand for pool water heating. In this paper, a mathematical model of the swimming pool was made to assess energy demands of an indoor swimming pool building. The mathematical model of the swimming pool is used with the created multi-zone building model in TRNSYS software to determine pool hall energy demand and pool losses. Energy loss for pool water and pool hall heating and ventilation are analyzed for different target pool water and air temperatures. The simulation showed that pool water heating accounts for around 22%, whereas heating and ventilation of the pool hall for around 60% of the total pool hall heat demand. With a change of preset controller air and water temperatures in simulations, evaporation loss was in the range 46-54% of the total pool losses. A solar thermal sanitary hot water system was modelled and simulated to analyze it's potential for energy savings of the presented demand side model. The simulation showed that up to 87% of water heating demands could be met by the solar thermal system, while avoiding stagnation.
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Azimian, Mahdi, Vahid Amir, Reza Habibifar y Hessam Golmohamadi. "Probabilistic Optimization of Networked Multi-Carrier Microgrids to Enhance Resilience Leveraging Demand Response Programs". Sustainability 13, n.º 11 (21 de mayo de 2021): 5792. http://dx.doi.org/10.3390/su13115792.
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Microgrids have emerged as a practical solution to improve the power system resilience against unpredicted failures and power outages. Microgrids offer substantial benefits for customers through the local supply of domestic demands as well as reducing curtailment during possible disruptions. Furthermore, the interdependency of natural gas and power networks is a key factor in energy systems’ resilience during critical hours. This paper suggests a probabilistic optimization of networked multi-carrier microgrids (NMCMG), addressing the uncertainties associated with thermal and electrical demands, renewable power generation, and the electricity market. The approach aims to minimize the NMCMG costs associated with the operation, maintenance, CO2e emission, startup and shutdown cost of units, incentive and penalty payments, as well as load curtailment during unpredicted failures. Moreover, two types of demand response programs (DRPs), including time-based and incentive-based DRPs, are addressed. The DRPs unlock the flexibility potentials of domestic demands to compensate for the power shortage during critical hours. The heat-power dual dependency characteristic of combined heat and power systems as a substantial technology in microgrids is considered in the model. The simulation results confirm that the suggested NMCMG not only integrates the flexibility potentials into the microgrids but also enhances the resilience of the energy systems.
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Sancho-Bastos, Francisco y Horacio Perez-Blanco. "Cogeneration System Simulation and Control to Meet Simultaneous Power, Heating, and Cooling Demands". Journal of Engineering for Gas Turbines and Power 127, n.º 2 (1 de abril de 2005): 404–9. http://dx.doi.org/10.1115/1.1789993.
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Gas turbines are projected to meet increasing power demand throughout the world. Cogeneration plants hold the promise of increased efficiency at acceptable cost. In a general case, a cogen plant could be able to meet power, heating and cooling demands. Yet those demands are normally uncoupled. Control and storage strategies need to be explored to ensure that each independent demand will be met continuously. A dynamic model of a mid-capacity system is developed, including gas and steam turbines, two heat recovery steam generators (HRSG) and an absorption-cooling machine. Controllers are designed using linear quadratic regulators (LQR) to control two turbines and a HRSG with some novelty. It is found that the power required could be generated exclusively with exhaust gases, without a duct burner in the high-pressure HRSG. The strategy calls for fuel and steam flow rate modulation for each turbine. The stability of the controlled system and its performance are studied and simulations for different demand cases are performed.
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Nizetic, Sandro, Roko Gizdic, Ankit Yadav y Miro Bugarin. "Integrated Split Heat Pump System for Building Applications". Applied Mechanics and Materials 705 (diciembre de 2014): 263–67. http://dx.doi.org/10.4028/www.scientific.net/amm.705.263.
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In this paper, a design of a specific hybrid energy system is elaborated for small scale applications in building facilities of residential or commercial purpose. The energy system is assembled from existing market available technologies that include implementation of a heat pump technology, photovoltaic system and of a standard accumulation boiler for the preparation of hot water. The developed energy system is assumed to be used in mild climates where a heat pump system can be efficiently used throughout the year. According to the gained experimental results the coefficient of the performance for the cooling mode can be expected between 5.0 and 6.0, which prove that the proposed system is highly energy efficient. The developed energy system can cover both cooling and heating demands and also demands for domestic hot water and it represents a totally renewable energy system.
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Melo, Filipi, Eduardo Pina y Monica Carvalho. "Optimization and sensitivity analyses of a combined cooling, heat and power system for a residential building". Thermal Science, n.º 00 (2020): 335. http://dx.doi.org/10.2298/tsci200718335m.
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In the quest for a better use of energy resources, energy integration and cogeneration strategies have been employed in the industrial and commercial sectors with considerable benefits realized. However, the residential sector remains underexplored. An optimization procedure should be carried out whenever there is a need to ensure or verify the economic viability of an energy system. This study uses Mixed Integer Linear Programming to optimize the energy supply to a residential building, with 20 floors and 40 apartments, located in the city of Jo?o Pessoa (Northeast Brazil). The equipment available includes gas engines, electric and natural gas boilers, heat exchangers, cooling towers, and absorption and mechanical chillers. The optimization establishes the optimal system configuration and operational strategy (operation throughout the year). Economic, technical, and legal aspects were considered in the minimization of the total annual costs associated with the building?s energy supply. The energy demands were calculated on an hourly basis, throughout one year, by the EnergyPlus software and corresponded to hot water (83 MWh/year), electricity (171 MWh/year) and cooling (242 MWh/year) demands. The optimal system was entirely reliant on the electric grid to meet the electricity demand directly and to satisfy heating and cooling demands by means of an electric hot water boiler and a mechanical chiller. The optimal solution is tested by varying, within reasonable limits, selected parameters: natural gas and electricity tariffs, the behavior of residents, amortization factor and relationship between the tariffs of electricity and natural gas.
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Fraga, Carolina, Pierre Hollmuller, Stefan Schneider y Bernard Lachal. "Heat pump systems for multifamily buildings: Potential and constraints of several heat sources for diverse building demands". Applied Energy 225 (septiembre de 2018): 1033–53. http://dx.doi.org/10.1016/j.apenergy.2018.05.004.
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Watson, S. D., K. J. Lomas y R. A. Buswell. "How will heat pumps alter national half-hourly heat demands? Empirical modelling based on GB field trials". Energy and Buildings 238 (mayo de 2021): 110777. http://dx.doi.org/10.1016/j.enbuild.2021.110777.
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Moser, Christoph, Gerald Englmair, Hermann Schranzhofer y Andreas Heinz. "Simulation Study of a Novel Solar Thermal Seasonal Heat Storage System Based on Stable Supercooled PCM for Space Heating and Domestic Hot Water Supply of Single Family Houses". Applied Mechanics and Materials 887 (enero de 2019): 650–58. http://dx.doi.org/10.4028/www.scientific.net/amm.887.650.
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A TRNSYS model of a novel PCM heat storage, utilizing stable supercooling of Sodium Acetate Trihydrate (SAT), is presented. To achieve high solar fractions in heat supply of single family houses, the necessary integration of big water volumes is challenging. To evaluate its functionality, a system model of a solar thermal combisystem for space heating and domestic hot water supply for dynamic system simulation was built. The key component is a PCM volume for long term heat storage. While conventional heat storage concepts with SAT release the latent heat a few degrees below the melting temperature, with the concept of stable supercooling latent heat can be stored for long periods of time at ambient temperature. This allows the design of a partly loss-free storage. Solar fractions were evaluated for simulation runs with two building variations. Annual specific space heating demands of 15 and 30 kWh/(m2a) and a domestic hot water demand of a typical single family house were considered. A sensitivity analysis on solar fractions of domestic heat supply was performed by variation of the collector field and the PCM volume. While the increase of the PCM volume from 4.5 m3 to 9 m3 shows moderate effects in all simulation runs, an increase of the collector area has substantial effects on the share of solar heat on the total energy demand of the building.
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Rus, Alexandru, Vlad Martian y Mihai Nagi. "Study of Height Influence of Heat Exchanger Tanks on Overall Pressure Drop". Applied Mechanics and Materials 659 (octubre de 2014): 446–49. http://dx.doi.org/10.4028/www.scientific.net/amm.659.446.
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In the context of a constant demand of more compact and efficient heat exchangers, the need for thoroughly researching the influence of the construction parameters impact on heat exchanger's performances arises. The purpose of the paper is to present the numerical results of such a research, carried out at RAAL S.A. with the support of "Politehnica" University of Timişoara. The research consists of assessing the effects of the geometric characteristics, the height in particular, of the inlet and outlet tanks of a water cooler on overall pressure drop, through Computational Fluid Dynamics. The structural complexity of heat exchangers demands that the analysis be divided into multiple, less complex models, in order to achieve accurate and truthful results within a reasonable amount of time and use of computational resources. The paper also focuses on developing a viable method for accomplishing numerical analyses on heat exchangers' parameters.
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Riise, Raymond y Bjørn R. Sørensen. "Integration of Multiple In-House Heat Stations into One Energy Flexible Heat System". Applied Mechanics and Materials 291-294 (febrero de 2013): 1777–88. http://dx.doi.org/10.4028/www.scientific.net/amm.291-294.1777.
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This study is focused towards assessing the potential for energy savings and cost reduction by integrating multiple in-house heat stations in several buildings into one larger energy flexible heat system. All existing boilers in stand-alone systems are kept as production units of a new merged system, and will be in addressed and operated when the condition demands it. In this study, energy and cost calculations are done on an hourly basis. Which combinations of boilers to be used in each time step are determined from the lowest running cost for each time step. The results of the case study show a clear savings potential for both energy and costs.
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Liu, Mingzhe, Ryozo Ooka, Toshiyuki Hino, Ke Wen, Wonjun Choi, Doyun Lee, Shintaro Ikeda y Djafar Reza Palasz. "Experimental performance analysis of a multiple-source and multiple-use heat pump system: winter field experiment and heating operation performance evaluation". E3S Web of Conferences 111 (2019): 01076. http://dx.doi.org/10.1051/e3sconf/201911101076.
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We herein report the development of a distributed heat pump system that can utilize a variety of renewable energy sources to meet different building heating and cooling demands (i.e., a multiple source and multiple use heat pump system, MMHP). In this system, a water circulating loop is used to connect ground heat exchangers, a unique sky-source heat pump, and various heat pumps for heating and cooling purposes to form a thermal network within a building. This distribution increases the flexibility of the system and allows an improved matching of supply and demand. To evaluate the system performance, an experimental house was constructed, and a winter field experiment was conducted. We found that the reported heat pump for floor heating achieved a stable operation with a high coefficient of performance of ~11.5, while the heat collecting operation performance of the sky-source heat pump varied significantly depending on the amount of solar radiation and the outside air temperature. Finally, since the sky-source heat pump contributes to an improvement in the whole system performance, it appears that there is still room for improved regarding the whole system performance by adjusting the operating and control strategy.
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Miller, Norman L., Katharine Hayhoe, Jiming Jin y Maximilian Auffhammer. "Climate, Extreme Heat, and Electricity Demand in California". Journal of Applied Meteorology and Climatology 47, n.º 6 (1 de junio de 2008): 1834–44. http://dx.doi.org/10.1175/2007jamc1480.1.
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Abstract Over the twenty-first century, the frequency of extreme-heat events for major cities in heavily air conditioned California is projected to increase rapidly. Extreme heat is defined here as the temperature threshold for the 90th-percentile excedence probability (T90) of the local warmest summer days under the current climate. Climate projections from three atmosphere–ocean general circulation models, with a range of low to midhigh temperature sensitivity forced by the Special Report on Emission Scenarios higher, middle, and lower emission scenarios, indicate that these increases in temperature extremes and variance are projected to exceed the rate of increase in mean temperature. Overall, projected increases in extreme heat under the higher A1fi emission scenario by 2070–99 tend to be 20%–30% higher than those projected under the lower B1 emission scenario. Increases range from approximately 2 times the present-day number of days for inland California cities (e.g., Sacramento and Fresno), up to 4 times for previously temperate coastal cities (e.g., Los Angeles and San Diego), implying that present-day “heat wave” conditions may dominate summer months—and patterns of electricity demand—in the future. When the projected extreme heat and observed relationships between high temperature and electricity demand for California are mapped onto current availability, maintaining technology and population constant for demand-side calculations, a potential for electricity deficits as high as 17% during T90 peak electricity demand periods is found. Similar increases in extreme-heat days are likely for other southwestern U.S. urban locations, as well as for large cities in developing nations with rapidly increasing electricity demands. In light of the electricity response to recent extreme-heat events, such as the July 2006 heat waves in California, Missouri, and New York, these results suggest that future increases in peak electricity demand will challenge current transmission and supply methods as well as future planned supply capacities when population and income growth are taken into account.
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Urbancl, Danijela, Peter Trop y Darko Goricanec. "Geothermal heat potential - the source for heating greenhouses in Southestern Europe". Thermal Science 20, n.º 4 (2016): 1061–71. http://dx.doi.org/10.2298/tsci151129155u.
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The paper presents economically evaluated solutions for heating greenhouses with geothermal potential, if the same greenhouse is placed in two different locations in Southeastern Europe, one in Slovenia and the other in Serbia. The direct geothermal water exploitation using heat exchangers is presented and the remaining heat potential of already used geothermal water is exploited using high temperature heat pumps. Energy demands for heating greenhouses are calculated considering climatic parameters of both locations. Furthermore, different constructions materials are taken into account, and energy demands are evaluated if the same greenhouse is made of 4 mm toughened single glass, double insulated glass or polycarbonate plates. The results show that the geothermal energy usage is economically feasible in both locations, because payback periods are in range from two to almost eight years for different scenarios.
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Ghoreishi-Madiseh, Seyed, Ali Fahrettin Kuyuk, Marco Rodrigues de Brito, Durjoy Baidya, Zahra Torabigoodarzi y Amir Safari. "Application of Borehole Thermal Energy Storage in Waste Heat Recovery from Diesel Generators in Remote Cold Climate Locations". Energies 12, n.º 4 (18 de febrero de 2019): 656. http://dx.doi.org/10.3390/en12040656.
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Remote communities that have limited or no access to the power grid commonly employ diesel generators for communal electricity provision. Nearly 65% of the overall thermal energy input of diesel generators is wasted through exhaust and other mechanical components such as water-jackets, intercoolers, aftercoolers, and friction. If recovered, this waste heat could help address the energy demands of such communities. A viable solution would be to recover this heat and use it for direct heating applications, as conversion to mechanical power comes with significant efficiency losses. Despite a few examples of waste heat recovery from water-jackets during winter, this valuable thermal energy is often discarded into the atmosphere during the summer season. However, seasonal thermal energy storage techniques can mitigate this issue with reliable performance. Storing the recovered heat from diesel generators during low heat demand periods and reusing it when the demand peaks can be a promising alternative. At this point, seasonal thermal storage in shallow geothermal reserves can be an economically feasible method. This paper proposes the novel concept of coupling the heat recovery unit of diesel generators to a borehole seasonal thermal storage system to store discarded heat during summer and provide upgraded heat when required during the winter season on a cold, remote Canadian community. The performance of the proposed ground-coupled thermal storage system is investigated by developing a Computational Fluid Dynamics and Heat Transfer model.
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Wallmark, Cecilia y Per Alvfors. "Design of stationary PEFC system configurations to meet heat and power demands". Journal of Power Sources 106, n.º 1-2 (abril de 2002): 83–92. http://dx.doi.org/10.1016/s0378-7753(01)01058-8.
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Teixeira, Marcos A. "Heat and power demands in babassu palm oil extraction industry in Brazil". Energy Conversion and Management 46, n.º 13-14 (agosto de 2005): 2068–74. http://dx.doi.org/10.1016/j.enconman.2004.10.014.
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Sinha, Rakesh, Birgitte Bak-Jensen, Jayakrishnan Radhakrishna Pillai y Hamidreza Zareipour. "Flexibility from Electric Boiler and Thermal Storage for Multi Energy System Interaction". Energies 13, n.º 1 (24 de diciembre de 2019): 98. http://dx.doi.org/10.3390/en13010098.
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Active use of heat accumulators in the thermal system has the potential for achieving flexibility in district heating with the power to heat (P2H) units, such as electric boilers (EB) and heat pumps. Thermal storage tanks can decouple demand and generation, enhancing accommodation of sustainable energy sources such as solar and wind. The overview of flexibility, using EB and storage, supported by investigating the nature of thermal demand in a Danish residential area, is presented in this paper. Based on the analysis, curve-fitting tools, such as neural net and similar day method, are trained to estimate the residential thermal demand. Utilizing the estimated demand and hourly market spot price of electricity, the operation of the EB is scheduled for storing and fulfilling demand and minimizing energy cost simultaneously. This demonstrates flexibility and controlling the EB integrated into a multi-energy system framework. Results show that the curve fitting tool is effectively suitable to acknowledge thermal demands of residential area based on the environmental factor as well as user behaviour. The thermal storage has the capability of operating as a flexible load to support P2H system as well as minimize the effect of estimation error in fulfilling actual thermal demand simultaneously.
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Gao, Xiaoyu, Chengying Qi, Guixiang Xue, Jiancai Song, Yahui Zhang y Shi-ang Yu. "Forecasting the Heat Load of Residential Buildings with Heat Metering Based on CEEMDAN-SVR". Energies 13, n.º 22 (20 de noviembre de 2020): 6079. http://dx.doi.org/10.3390/en13226079.
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The energy demand of the district heating system (DHS) occupies an important part in urban energy consumption, which has a great impact on the energy security and environmental protection of a city. With the gradual improvement of people’s economic conditions, different groups of people now have different demands for thermal energy for their comfort. Hence, heat metering has emerged as an imperative for billing purposes and sustainable management of energy consumption. Therefore, forecasting the heat load of buildings with heat metering on the demand side is an important management strategy for DHSs to meet end-users’ needs and maintain energy-saving regulations and safe operation. However, the non-linear and non-stationary characteristics of buildings’ heat load make it difficult to predict consumption patterns accurately, thereby limiting the capacity of the DHS to deliver on its statutory functions satisfactorily. A novel ensemble prediction model is proposed to resolve this problem, which integrates the advantages of Complete Ensemble Empirical Mode Decomposition with Adaptive Noise (CEEMDAN) and support vector regression (SVR), called CEEMDAN-SVR in this paper. The proposed CEEMDAN-SVR algorithm is designed to automatically decompose the intrinsic mode according to the characteristics of heat load data to ensure an accurate representation of heat load patterns on multiple time scales. It will also be useful for developing an accurate prediction model for the buildings’ heat load. In formulating the CEEMDAN-SVR model, the heat load data of three different buildings in Xingtai City were acquired during the heating season of 2019–2020 and employed to conduct detailed comparative analysis with modern algorithms, such as extreme tree regression (ETR), forest tree regression (FTR), gradient boosting regression (GBR), support vector regression (SVR, with linear, poly, radial basis function (RBF) kernel), multi-layer perception (MLP) and EMD-SVR. Experimental results reveal that the performance of the proposed CEEMDAN-SVR model is better than the existing modern algorithms and it is, therefore, more suitable for modeling heat load forecasting.
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Liu, Xin-Rui, Si-Luo Sun, Qiu-Ye Sun y Wei-Yang Zhong. "Time-Scale Economic Dispatch of Electricity-Heat Integrated System Based on Users’ Thermal Comfort". Energies 13, n.º 20 (20 de octubre de 2020): 5505. http://dx.doi.org/10.3390/en13205505.
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The electricity-heat integrated system can realize the cascade utilization of energy and the coordination and complementarity between multiple energy sources. In this paper, considering the thermal comfort of users, taking into account the difference in dynamic characteristics of electric and heating networks and the response of users’ demands, a dispatch model is constructed. In this model, taking into account the difference in the time scale of electric and thermal dispatching, optimization of the system can be improved by properly extending the thermal balance cycle of the combined heat and power (CHP) unit. Based on the time-of-use electricity prices and heat prices to obtain the optimal energy purchase cost, a user demand response strategy is adopted. Therefore, a minimum economic cost on the energy supply side and a minimum energy purchase cost on the demand side are considered as a bilevel optimization strategy for the operation of the system. Finally, using an IEEE 30 nodes power network and a 31 nodes heating network to form an electricity-heat integrated system, the simulation results show that the optimal thermal balance cycle can maximize the economic benefits on the premise of meeting the users’ thermal comfort and the demand response can effectively realize the wind curtailment and improve the system economy.
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Wurm, Michael, Ariane Droin, Thomas Stark, Christian Geiß, Wolfgang Sulzer y Hannes Taubenböck. "Deep Learning-Based Generation of Building Stock Data from Remote Sensing for Urban Heat Demand Modeling". ISPRS International Journal of Geo-Information 10, n.º 1 (12 de enero de 2021): 23. http://dx.doi.org/10.3390/ijgi10010023.
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Cities are responsible for a large share of the global energy consumption. A third of the total greenhouse gas emissions are related to the buildings sector, making it an important target for reducing urban energy consumption. Detailed data on the building stock, including the thermal characteristics of individual buildings, such as the construction type, construction period, and building geometries, can strongly support decision-making for local authorities to help them spatially localize buildings with high potential for thermal renovations. In this paper, we present a workflow for deep learning-based building stock modeling using aerial images at a city scale for heat demand modeling. The extracted buildings are used for bottom-up modeling of the residential building heat demand based on construction type and construction period. The results for DL-building extraction exhibit F1-accuracies of 87%, and construction types yield an overall accuracy of 96%. The modeled heat demands display a high level of agreement of R2 0.82 compared with reference data. Finally, we analyze various refurbishment scenarios for construction periods and construction types, e.g., revealing that the targeted thermal renovation of multi-family houses constructed between the 1950s and 1970s accounts for about 47% of the total heat demand in a realistic refurbishment scenario.
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Zhang, Chuanhui. "Progress in semicrystalline heat-resistant polyamides". e-Polymers 18, n.º 5 (25 de septiembre de 2018): 373–408. http://dx.doi.org/10.1515/epoly-2018-0094.
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AbstractFor the past decade, market demands for semicrystalline heat-resistant polyamides (HPAs) with excellent performance and significantly improved heat-resistant temperature has grown rapidly, and they are widely used in the electronic and electrical industry, as light-emitting diodes and in the automobile field (as metal replacements). Industrialized HPAs to date, include PA46, PA6T copolyamides, PA9T and PA10T. Other HPAs being researched include full aliphatic HPA, PA5T, long carbon chain HPA, PXD10 and alicyclic HPA. This review addresses progress in HPAs, especially the properties of HPA, patents analysis and polymerization processes.
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Blomqvist, Stefan, Lina La Fleur, Shahnaz Amiri, Patrik Rohdin y Louise Ödlund (former Trygg). "The Impact on System Performance When Renovating a Multifamily Building Stock in a District Heated Region". Sustainability 11, n.º 8 (12 de abril de 2019): 2199. http://dx.doi.org/10.3390/su11082199.
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In Sweden, 90% of multifamily buildings utilize district heat and a large portion is in need of renovation. The aim is to analyze the impact of renovating a multifamily building stock in a district heating and cooling system, in terms of primary energy savings, peak power demands, electricity demand and production, and greenhouse gas emissions on local and global levels. The study analyzes scenarios regarding measures on the building envelope, ventilation, and substitution from district heat to ground source heat pump. The results indicate improved energy performance for all scenarios, ranging from 11% to 56%. Moreover, the scenarios present a reduction of fossil fuel use and reduced peak power demand in the district heating and cooling system ranging from 1 MW to 13 MW, corresponding to 4–48 W/m2 heated building area. However, the study concludes that scenarios including a ground source heat pump generate significantly higher global greenhouse gas emissions relative to scenarios including district heating. Furthermore, in a future fossil-free district heating and cooling system, a reduction in primary energy use will lead to a local reduction of emissions along with a positive effect on global greenhouse gas emissions, outperforming measures with a ground source heat pump.
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Wahlström, Åsa y Mari-Liis Maripuu. "Additional requirement to the Swedish nearly zero energy requirements". E3S Web of Conferences 246 (2021): 14002. http://dx.doi.org/10.1051/e3sconf/202124614002.
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This study has analysed which options would be appropriate to use as additional requirements to the main requirement of primary energy number in the new Swedish building regulations. The starting point is to ensure that buildings are built with good qualitative properties in terms of the building envelope so that low energy use can be maintained throughout the life of the building despite changes in installation systems or the building’s occupancy. The additional requirements should aim to minimize energy losses, i.e., to ensure that the building's total energy demand is low. The following possible additional requirements have been examined: net energy demand, net energy demand for heating, heat power demand, heat loss rate and average heat transfer coefficient. In order to ensure that the additional requirements will work as desired and to explore possibilities with, and identify the consequences of, the various proposals, calculations have been made for four different categories of buildings: single-family houses, apartment buildings, schools and offices. The results show that the suggested option net energy demand will not contribute to any additional benefits in relation to primary energy number. The other options analysed have both advantages and disadvantages and it is difficult to find a single additional requirement that fulfils all the pre-set demands.
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Hanna, L. M. y P. W. Scherer. "Regional control of local airway heat and water vapor losses". Journal of Applied Physiology 61, n.º 2 (1 de agosto de 1986): 624–32. http://dx.doi.org/10.1152/jappl.1986.61.2.624.
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The regulation of local heat and water vapor losses along the respiratory tract is examined based on a theoretical model of respiratory air conditioning and physiological data. The theoretical model is a quasi-steady one-dimensional model descriptive of the localized process of heat and water transport within the airways. During nasal breathing the model is most sensitive to the following two parameters: 1) the gradient of blood temperature along the airway wall and 2) the nasal air space volume. Thermoregulatory control of these two factors within the primary conditioning region, the upper airway, establishes the overall respiratory heat and water loss. Upper airway thermoregulation, however, also effects the heat and water demands placed on the secondary conditioning region, the tracheobronchial airways. Similar to the upper airway, the tracheobronchial airway wall temperature varies in response to changing demands. The bronchial circulation is shown to provide a major source of heat within the first several bronchial generations where the greatest heat and water fluxes within the lung are predicted to occur. Control of the bronchial blood flow may therefore directly influence the bronchoconstrictive response in asthmatics.
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Kreitmair, Monika J., Nikolas Makasis, Asal Bidarmaghz, Ricky L. Terrington, Gareth J. Farr, Johanna M. Scheidegger y Ruchi Choudhary. "Effect of anthropogenic heat sources in the shallow subsurface at city-scale". E3S Web of Conferences 205 (2020): 07002. http://dx.doi.org/10.1051/e3sconf/202020507002.
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Rapid rates of urbanisation are placing growing demands on cities for accommodation and transportation, with increasing numbers of basements and tunnel networks being built to meet these rising demands. Such subsurface structures constitute continuous heat sources and sinks, particularly if maintained at comfortable temperatures. At the city-scale, there is limited understanding of the effect of heat exchange of underground infrastructures with their environments, in part due to limited availability of long-term underground temperature data. The effects of underground temperature changes due anthropogenic heat fluxes can be significant, impacting ventilation and cooling costs of underground spaces, efficiency of geo-energy systems, quality and quantity of groundwater flow, and the health and maintenance of underground structures. In this paper we explore the impact of anthropogenic subsurface structures on the thermal climate of the shallow subsurface by developing a heat transfer model of the city of Cardiff, UK, utilising a recently developed semi-3D modelling approach.
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Zhou, Guang Hui, Shi Wei Feng, Si Qi Cui y Yin Liu. "Review Status on High Temperature Heat Pumps". Applied Mechanics and Materials 170-173 (mayo de 2012): 2550–53. http://dx.doi.org/10.4028/www.scientific.net/amm.170-173.2550.
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A heat pump is a kind of energy saving equipment. It can effectively improve the grade of low temperature renewable and waste energy. Because of the increasing demands for higher temperature energy in many industrial processes and other fields, the development and research of high temperature heat pumps have been becoming more and more pressing and significant. This paper briefly summarizes the development status in two aspects: the development of working fluids and system features and characteristics of different cycle types.
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Winterbone, D. E. "Engines versus electrons: The future of power production". Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 214, n.º 1 (1 de febrero de 2000): 1–11. http://dx.doi.org/10.1243/0957650001537804.
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The demands for energy are increasing as countries become richer, and if all mankind achieved the per capita energy consumption of the United States then the total energy consumption of the world would rise by a factor of about 4.5. This would make a large demand on fuel supplies and probably increase pollution beyond a sustainable level. This paper examines the limits to the theoretical efficiency of power generation, including both heat engines and fuel cells, and demonstrates that thermal efficiencies of above 60 per cent are achievable in each case if combined plants are used. It is shown that the fuel cell has benefits over the heat engine when the plant operates for a significant time at low load.
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Oppermann, M., K. Widmer, R. Reber, H. Sledzik, P. Schuh, U. Schmid, B. Bunz, S. Chartier, K. Drüeke y M. Bedenbecker. "GaN based RF Modules - Demands & Needs for Packaging". International Symposium on Microelectronics 2011, n.º 1 (1 de enero de 2011): 000896–99. http://dx.doi.org/10.4071/isom-2011-tha1-paper4.
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GaN/SiC based powerbars and MMICs are the youngest semiconductor devices which have arrived in the field of Radio Frequency modules and applications, e.g. radar, communication links and high power transmitters and amplifiers. Nearly 5 years ago, the first GaN devices were used in the fields of telecommunication equipment, mainly in base-station amplifiers and today GaN devices are more and more part of modern radar applications, like T/R (Transmit/Receive) modules in AESA (Active Electronically Scanned Array) antennas. The main advantages of GaN/SiC semiconductor devices in comparison to GaAs-devices are the higher bandwidth, higher robustness level and the higher operation voltage. Another big issue of GaN is the higher power density, with in minimum 4 times higher values compared to GaAs. Therefore the assembly of GaN MMICs and powerbars on heatsinks and module-baseplates is a big challenge for soldering technology. An absolute minimum of voids between backside of the GaN/SiC devices and the heatsink is necessary to guarantee an optimised heat transfer during operation. Different package materials and technologies are on the market and big international package suppliers deal with new material combinations, like sandwich structures of Cu and Mo. Materials like Al-diamond are used for heatsink materials and with special tests and measurements the results of heat transfer studies will be shown. In this paper examples of power amplifiers, operating in the frequency range of 2–6 GHz and 6–18GHz, and a typical X-Band Frontend will be shown and the RF results will be discussed.
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Nehasil, Ondřej y Daniel Adamovský. "Utilization of Indirect Adiabatic Cooling in Heat Recovery Device". Advanced Materials Research 649 (enero de 2013): 307–10. http://dx.doi.org/10.4028/www.scientific.net/amr.649.307.
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Decreasing heat load of buildings and their cooling is a major problem affecting the quality of both inner environment and air-conditioning system's energy demands. One of the alternatives using regular components of a standard air-conditioning unit is indirect adiabatic cooling. By means of a customized calculation procedure, this article demonstrates performance possibilities, energy savings and the economic benefits of indirect adiabatic cooling connected with a heat recovery heat exchanger on two air-conditioning unit alternatives.
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Cola, F., A. Romagnoli y J. Hey. "An evaluation of the technologies for heat recovery to meet onsite cooling demands". Energy Conversion and Management 121 (agosto de 2016): 174–85. http://dx.doi.org/10.1016/j.enconman.2016.05.021.
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Winkler, Markus, David Rapp, Andreas Mahlke, Felix Zunftmeister, Marc Vergez, Erik Wischerhoff, Jürgen Clade, Kilian Bartholomé y Olaf Schäfer-Welsen. "Small-Sized Pulsating Heat Pipes/Oscillating Heat Pipes with Low Thermal Resistance and High Heat Transport Capability". Energies 13, n.º 7 (5 de abril de 2020): 1736. http://dx.doi.org/10.3390/en13071736.
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Electronics (particularly power electronics) are the core element in many energy-related applications. Due to the increasing power density of electronic parts, the demands on thermal management solutions have risen considerably. As a novel passive and highly efficient cooling technology, pulsating heat pipes (PHPs) can transfer heat away from critical hotspots. In this work, we present two types of small and compact PHPs with footprints of 50 × 100 mm2, thicknesses of 2 and 2.5 mm and with high fluid channel density, optimized for cooling electronic parts with high power densities. The characterization of these PHPs was carried out with a strong relation to practical applications, revealing excellent thermal properties. The thermal resistance was found to be up to 90% lower than that of a comparable solid copper plate. Thus, a hot part with defined heating power would remain at a much lower temperature level and, for the same heater temperature, a much larger heating power could be applied. Moreover, the dependence of PHP operation and thermal properties on water and air cooling, condenser area size and orientation is examined. Under some test configurations, dryout conditions are observed which could be avoided by choosing an appropriate size for the fluid channels, heater and condenser.
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Li, Bo, Jianding Li, Huaiyu Shao y Liqing He. "Mg-Based Hydrogen Absorbing Materials for Thermal Energy Storage—A Review". Applied Sciences 8, n.º 8 (15 de agosto de 2018): 1375. http://dx.doi.org/10.3390/app8081375.
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Utilization of renewable energy such as solar, wind, and geothermal power, appears to be the most promising solution for the development of sustainable energy systems without using fossil fuels. Energy storage, especially to store the energy from fluctuating power is quite vital for smoothing out energy demands with peak/off-peak hour fluctuations. Thermal energy is a potential candidate to serve as an energy reserve. However, currently the development of thermal energy storage (TES) by traditional physical means is restricted by the relatively low energy density, high temperature demand, and the great thermal energy loss during long-period storage. Chemical heat storage is one of the most promising alternatives for TES due to its high energy density, low energy loss, flexible temperature range, and excellent storage duration. A comprehensive review on the development of different types of Mg-based materials for chemical heat storage is presented here and the classic and state-of-the-art technologies are summarized. Some related chemical principles, as well as heat storage properties, are discussed in the context. Finally, some dominant factors of chemical heat storage materials are concluded and the perspective is proposed for the development of next-generation chemical heat storage technologies.
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Mancic, Marko, Dragoljub Zivkovic, Milan Djordjevic y Milena Rajic. "Optimization of a polygeneration system for energy demands of a livestock farm". Thermal Science 20, suppl. 5 (2016): 1285–300. http://dx.doi.org/10.2298/tsci16s5285m.
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A polygeneration system is an energy system capable of providing multiple utility outputs to meet local demands by application of process integration. This paper addresses the problem of pinpointing the optimal polygeneration energy supply system for the local energy demands of a livestock farm in terms of optimal system configuration and optimal system capacity. The optimization problem is presented and solved for a case study of a pig farm in the paper. Energy demands of the farm, as well as the super-structure of the polygeneration system were modelled using TRNSYS software. Based on the locally available resources, the following polygeneration modules were chosen for the case study analysis: a biogas fired internal combustion engine co-generation module, a gas boiler, a chiller, a ground water source heat pump, solar thermal collectors, photovoltaic collectors, and heat and cold storage. Capacities of the polygeneration modules were used as optimization variables for the TRNSYS-GenOpt optimization, whereas net present value, system primary energy consumption, and CO2 emissions were used as goal functions for optimization. A hybrid system composed of biogas fired internal combustion engine based co-generation system, adsorption chiller solar thermal and photovoltaic collectors, and heat storage is found to be the best option. Optimal heating capacity of the biogas co-generation and adsorption units was found equal to the design loads, whereas the optimal surface of the solar thermal array is equal to the south office roof area, and the optimal surface of the PV array corresponds to the south facing animal housing building rooftop area.