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Schaefer, Laura Atkinson. "Single presssure absorption heat pump analysis." Diss., Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/17924.
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Santoyo-Gutierrez, Socrates. "Absorption heat pump assisted effluent purification." Thesis, University of Salford, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.245055.
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Gigos, Pierre-Antoine. "Modelling a Solar Driven Absorption Heat Pump." Thesis, KTH, Tillämpad termodynamik och kylteknik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-185684.
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Absorption Heat Pumps (AHP) have been developed since the late 19th century. They enable to produce cooling and heating directly from a heat source, unlike Compression Heat Pumps that require mechanical work. In the context of scarcity of resources and global warming, the company Helioclim develops solar air conditioning using an Absorption Heat Pump. The heat is gathered at rooftop solar concentrators and powers an ammonia-water AHP. The present study proposes an EES model of Helioclim’s AHP allowing assessing its performances under various operating conditions. Another aspect developed is the Modelling of the whole system (from solar energy to the economic assessment) in order to find the best parameters to propose to a potential client. Regarding EES model, three existing EES examples of AHP have been used. Those models, ranging from the simple single-stage ammonia AHP to a more complex GAX-cycle, did not correspond exactly to the features of Helioclim’s cycle. Therefore, a new model has been built: the position of the GAX and its connections to the other heat exchangers have been adapted and a recirculation in the generator has been proposed in order to correspond to Helioclim’s design. The model obtained is then used to assess the improvement of the performances with the GAX. It is also compared to the available experimental data. In the present study, a software program representing the whole solar air conditioning system is also developed, integrating the previous EES model. The software program considers the solar energy gathered by the collectors and deduces the energy transmitted to the heat pump. The EES model is then used to assess the performances of the heat pump in the operating conditions, allowing determining the produced cooling and heating. An economic and energy synthesis is produced, summarizing effectively the parameters and economic advantages of the installation. This software program allows sizing an installation for a client much more quickly than before.
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Forinash, David Michael. "Novel air-coupled heat exchangers for waste heat-driven absorption heat pumps." Thesis, Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/53897.
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A detailed investigation of novel air-coupled absorbers for use in a diesel engine exhaust-driven ammonia-water absorption system operating in extreme ambient conditions was conducted. Electrically driven vapor-compression systems are under scrutiny due to the environmental impact of synthetic refrigerants and the exacerbation of electric utility loads during peak demand periods. One alternative to vapor-compression systems is the absorption heat pump that uses environmentally benign working fluids and can be driven by a variety of heat sources, including waste heat and solar thermal processes. Direct air coupling of the absorber and condenser instead of indirect hydronic coupling can reduce absorption system size, complexity, and inefficiency, but materials compatibility issues with ammonia-water and the poor heat transfer properties of air present challenges.
Heat and mass transfer modeling was used to predict the performance of round-tube corrugated-fin and compact tube-array absorbers designed for a 2.64-kW absorption chiller operated in high ambient temperature (51.7°C) conditions. A single-pressure ammonia-water test facility was constructed and used in conjunction with a temperature- and humidity-controlled air-handling unit to evaluate the absorbers at design and off-design operating conditions. Absorber performance was recorded over a range of air temperatures (35-54.4°C), air flow rates (0.38-0.74 m3 s-1), inlet solution temperatures (92-102°C), concentrated solution flow rates (0.006-0.010 kg s-1), and concentrated solution concentrations (38-46%). At design conditions, round-tube corrugated-fin absorbers of 394 and 551 Fins Per Meter (FPM) demonstrated comparable performance (Q394-FPM,exp = 4.521±0.271 kW; Q551-FPM,exp = 4.680±0.260 kW), and measured heat transfer rates were 0.7-1.9% AAD higher than those predicted through modeling. The measured heat transfer rate in the prototype tube-array absorber was significantly lower than the values predicted at design conditions (Qprot,exp = 2.22±0.24 kW; Qprot,mod = 4.33 kW). Maldistribution of the two-phase flow in the tube array is the probable cause of the disparity between the prototype absorber data and model predictions. Results from this investigation can be used to guide the development of air-coupled heat and mass exchangers for compact absorption heat pumps.
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Vodenicker, John P. III. "Three dimesional graphics for the analysis of absorption heat pump cycles." Thesis, Georgia Institute of Technology, 1996. http://hdl.handle.net/1853/17401.
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Keinath, Christopher Mahlo. "Direct-fired heat pump for multi-pass water heating using microchannel heat and mass exchangers." Diss., Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/54330.
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Absorption heat pump water heaters offer improved performance compared to conventional direct-fired water heaters, with the potential for coefficients of performance well in excess of 1. A primary energy usage comparison with electric heat pumps shows that absorption systems can be competitive with current technology. However, the implementation of these systems in the residential and light commercial market has not been practical for several reasons, including a limited knowledgebase on absorption systems for this application and the lack of compact and economically viable heat and mass exchangers. An improved understanding of the coupled heat and mass transfer processes in thermally driven absorption systems to be used as heat pump water heaters was obtained over the course of this study. In addition, microchannel heat and mass exchangers that enable such compact gas-fired heat pump water heaters were developed and tested. Performance at design and off-design conditions over a range of water and ambient temperatures was simulated in detail with a system-level model developed for this purpose. The system-level model was coupled with a water-tank model to investigate several water heating scenarios including a cold start, response to a medium sized draw and response to stand-by losses. Heat and mass exchangers were designed using component-level heat and mass transfer models. The heat and mass exchangers were first installed and evaluated on a breadboard test facility. Insights from these experiments were then used to design and fabricate a monolithic unit integrating several of the microchannel heat and mass exchangers, coupled with a gas-fired desorber heat exchanger to yield a stand-alone water heater prototype. The performance of the prototype was investigated over a range of water and ambient temperatures. A comparison of results was performed to investigate the deviation between model predictions and experimental values. A refined model was developed that more accurately predicted experimental results. Energy-use and cost analyses were performed and showed the potentially significant energy savings of thermally driven heat pump water heaters.
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Kim, Sarah Sungeun. "An absorption refrigeration system using ionic liquid and hydrofluorocarbon working fluids." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/51783.
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Efficient heat management in energy intensive applications such as server and data centers has become a national concern due to the magnitude of the energy consumed. In that matter, the absorption refrigeration system is an attractive solution because the abundant waste heat available in the data centers can be recycled to run the heat pump, which will bring about significant cooling cost savings. The use of absorption refrigeration has been limited due to the drawbacks related to the working fluids in commercially available equipment. Recently, ionic liquids (ILs) have been suggested as the absorbent in absorption heat pumps due to their tunable properties, negligible volatility and high thermal stability.
The non-random-two-liquid-model was initially used to analyze the feasibility of the new IL based working fluid. Hydrofluorocarbons (HFCs) were paired with IL absorbents due to their good properties as refrigerants. The cooling-to-total-energy (CE) efficiency had a local maximum with respect to desorber temperature due to the solubility limit at lower temperatures and large heating requirements at higher temperatures. The waste heat recycling coefficient of performance (COP) continually increased with respect to desorber temperature and among the HFCs studied in this work, R134 gave the highest COP value, which is up to 40 times higher than that of typical vapor compression systems and 60 times higher than NH3/H2O and H2O/LiBr absorption refrigeration systems.
A Redlich-Kwong equation of state (RK-EOS) was employed for accurate computation of mixture properties over a wide range of operating conditions. Analysis using the RK-EOS model showed that the CE trend in refrigerants followed the trend of solubility in the [bmim][PF6] IL. However, the trend in COP was different from that of CE as the operating pressure ranges became an important factor. Required pumping work of the working fluids has also been analyzed using a two phase pressure drop equation and the results show that the impact of viscous IL flow is insignificant compared to the total pumping work.
The HFCs studied in this work have very similar structures. However, the extent of solubility and system efficiency in the same IL, [bmim][PF6], made a large difference. Most surprisingly, even when the refrigerant had the same chemical formula, the change in fluorine position in tetrafluoroethane showed significantly different system performance. The symmetrical tetrafluoroethane had superior CE and COP over the asymmetrical tetrafluoroethane most likely due to the higher probability to form hydrogen bonding with the absorbent. The computational results for various HFC/IL pairs show that in selecting the working fluid pairs, the refrigerant should have high overall solubility in the IL and a large gradient of solubility with respect to temperature. Also, refrigerants with small pressure ranges are preferred.
In addition to the simulation study, a bench-top absorption refrigeration system was built and operated using IL based working fluids for the first time. The effect of cooling was observed by operating the test system. The experimental results were congruent with the predictions from the modeling work. In conclusion, an absorption refrigeration system based on the IL chemical compressor has been shown to be a promising solution in applications which need efficient cooling and generate abundant waste heat.
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Borgås, Anders. "Development of the Hybrid Absorption Heat Pump Process at High Temperature Operation." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for elkraftteknikk, 2014. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-26361.
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Hybrid heat pumps with ammonia/water mixtures are identified as one of the most promising high temperature heat pump technologies. They are especially suited for processes with high temperature lifts, flexible regarding capacity control and external changes and enable the use of ammonia at higher temperatures than conventional vapour-compression heat pumps. A two-stage compression/absorption heat pump simulation model was developed in order to evaluate the thermodynamic process for high temperature operation. In simulation scenarios, waste heat was available at 50°C and the aim was to heat process water from 100°C to 150°C. Heat pump performance, temperature levels and pressure levels were some of the key results of the simulations. Secondary, it was developed a simulation model of a finned, annular tube cross-flow absorber in order to assess the dimensions of an absorber for heating air with an ammonia/water mixture. Both models were used in a simulation case where the compression/absorption heat pump was integrated in a spray drying process utilizing waste heat air at 35 °C.Simulations with the two-stage model showed that the scenarios with high water content in the vapour before the compressor, achieved the highest performances. Circulation ratios were higher, which resulted in a larger fraction of the mixture mass flow went through the compressor circuit, hence smaller compressor work. Although pressure ratios were higher, resulting absorber pressures were significantly lower. Some of the disadvantages with high water content were higher discharge temperatures, although discharge temperatures were high in all scenarios, and considerably lower vapour densities. In simulations were the discharge temperature was limited to 180 °C, the highest achieved COP was 1.81, while in simulations with no limitations to the discharge temperature, the highest COP was 2.53. Moreover, simulation scenarios without limitations to the discharge temperature resulted in lower absorber pressures, hence lower pressure ratios and higher performances. However, it resulted in discharge temperatures as high as 310 °C. Simulations with a desuperheater showed, provided that the minimum temperature difference between solution and heat sink does not occur at the absorber inlet, that a desuperheater provides no gain. Even when the minimum temperature difference occurs at the absorber inlet, there is only a small gain and it gets smaller with increasing circulation ratios.Dimensioning the absorber gave some unrealistic results in terms of an extreme ratio between absorber height and width/length. Even with the smallest obtained ratio, the height was 10 times the width, and the required surface area was significantly higher than for larger ratios. It is difficult to determine whether the results are due to errors in the simulation model or if it is difficult to obtain a noteworthy result with the simulation parameters. However, it is worth mentioning that the air mass flow rate was 15 times as high as the mixture mass flow rate. In the spray drying simulation case, the heat pump performance was 1.40 including the fan work. This performance was calculated with no limitation to the discharge temperature and with high water content in the vapour. With more realistic limitations, the performance would have been lower and the required. The required temperature lift in the case may have been somewhat high for the heat pump process.
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Sari, Ozgur Gokmen. "Exergy Analysis Of A Solar Assisted Absorption Heat Pump For Floor Heating System." Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/2/12604765/index.pdf.
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Solar assisted single-stage absorption heat pump (AHP) was used to supply energy to a floor-heating system by using the exergy methods. An existing duplex-house,in Ankara, with a heating load of 25.5 kW was analysed. Heating loads of the spaces in the building were calculated and a floor heating panel was modelled for each space leading to the capacity of the AHP before it was designed. Solar energy was delivered to the evaporator and high temperature heat input delivered to the genarator are met by auxiliary units operating with natural gas.The solar energy gained by flat-plate collectors was circulated through AHP.The anaysis performed according to the storage tank temperature reference value if the water temperature leaving the storage tank exceeds a predetermined value it is directly circulated through the floor heating system.
Exergue analysis were carried out with Mathcad program. Exergy analysis showed that irreversibility have an impact on absorption system performance.This study indicated which components in the system need to be improved thermally.A design procedure has been applied to a water-lithium-bromide absorption heat pump cycle and an optimisation procedure that consists of determinig the enthalpy, entropy ,exergy, temperature, mass flow rate in each component and coeficient of performance and exergetic coefficient of performance has been performed and tabulated.
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Sarı, Özgür Gökmen. "Energy analysis of a solar assisted absorption heat pump for floor heating system." Ankara : METU, 2004. http://etd.lib.metu.edu.tr/upload/12604765/index.pdf.
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Underwood, C. P. "An investigation into the dynamic thermal modelling and capacity control of the absorption cycle heat pump." Thesis, University of Newcastle Upon Tyne, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.375116.
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Herold, Keith Evan. "Thermodynamic properties of lithium bromide/water solutions with application to an absorption temperature boosting heat pump." Connect to resource, 1985. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1227545226.
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Van, der Walt Stefan. "The design and optimisation of a bubble pump for an aqua-ammonia diffusion absorption heat pump / Stefan van der Walt." Thesis, North-West University, 2012. http://hdl.handle.net/10394/9231.
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Energy shortages around the world necessitated research into alternative energy sources especially for domestic applications to reduce the load on conventional energy sources. This resulted in research done on the possibility of integrating solar energy with an aqua-ammonia diffusion absorption cycle specifically for domestic applications.
The bubble pump can be seen as the heart of the diffusion absorption cycle, since it is responsible, in the absence of a mechanical pump, to circulate the fluid and to desorb the refrigerant (ammonia) from the mixture. It is thus of paramount importance to ensure that the bubble pump is designed efficiently.
Various bubble pump simulation models have been developed over the years, but it was found that none of the existing models served as a good basis for application-specific design. Most of the models constrained too many parameters from the outset which made the investigation of the effects of certain parameters on the bubble pump’s performance impossible. According to the research, no bubble pump model investigated the effect of such a wide variety of factors including tube diameter, heat flux, mass flux, generator heat input and system pressure on the bubble pump’s lift height.
A simulation model for a bubble pump for integration with a solar-driven aqua-ammonia diffusion absorption cycle was developed. It serves as a versatile design model to optimise the bubble pump for a large variety of conditions as well as changes in parameters. It was achieved by constraining the bubble pump dimensions and parameters as little as possible. A unique feature of this model was the fact that the bubble pump tube was divided into segments of known quality which made the length of the pipe completely dependent on the flow inside the pipe. It also made the demarcation of the flow development inside the tube easier.
The model attempted to incorporate the most appropriate correlations for pressurised two-phase aqua-ammonia flow. The most appropriate void fraction correlation was found to be Abstract
The design and optimisation of a bubble pump for an aqua-ammonia diffusion absorption heat pump the Rouhani-Axelsson (Rouhani I) correlation. It was mainly due to its exclusive use of thermophysical properties and the vapour quality.
The most appropriate heat transfer coefficient that predicted the most realistic wall temperature, was the correlation from Riviera and Best (1999) which was the only correlation found in the literature developed with aqua-ammonia in mind. It was found that the published correlation could not reproduce their experimental results, and a modification of their correlation was made after which the simulation model’s results correlated well with the experimental values of Riviera and Best (1999).
The main goal of the simulation model was to determine the height that the bubble pump was capable of lifting at the slug to churn flow transition under various conditions. The effect of varying a variety of parameters on the bubble pump lift height was also investigated.
The results from Shelton & White Stewart (2002) were compared to the outputs of the simulation model, and it was found that their constraining of the submergence ratio limited their outputs, and that their heat inputs under different conditions was a bit optimistic. The simulation model’s outputs correlated well at higher tube diameters with the results from Shelton & White Stewart (2002), but at the lower diameters which was used in their study it was impossible to compare data, since their diameters was already in mini flow and micro flow regions. The temperatures also correlated well, all within 2% of the results from Shelton & White Stewart (2002).
It was found that there couldn’t be just one set of optimised conditions and values for the bubble pump, but that each cycle with differing specifications and operating conditions would yield a unique set of optimised parameters. It was for that reason very important not to constrain parameters beforehand without investigating its effect on the bubble pump first.Thesis (MIng (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2013.
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Hu, Jinshan. "Heat transfer and fluid flow characteristics in various micro devices for the development of micro absorption heat pump systems /." View abstract or full-text, 2007. http://library.ust.hk/cgi/db/thesis.pl?MECH%202007%20HU.
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Herold, Keith Evan. "Thermodynamic properties of lithium bromide/water solutions with application to an absorption temperature boosting heat pump /." The Ohio State University, 1986. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487261919111186.
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Determan, Matthew Delos. "Thermally activated miniaturized cooling system." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/29618.
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Thesis (Ph.D)--Mechanical Engineering, Georgia Institute of Technology, 2008.Committee Chair: Garimella, Srinivas; Committee Member: Allen, Mark; Committee Member: Fuller, Tom; Committee Member: Jeter, Sheldon; Committee Member: Wepfer, William. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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Bellander, Hampus. "Evaluation of a hygroscopic condenser." Thesis, KTH, Skolan för kemivetenskap (CHE), 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-49842.
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In Sweden the industries releases about 50 TWh / year of low temperature waste heat[1], often in the form of humid air flows. Today, conventional flue gas condensation is only exploiting a minor part of the energy from these flows. It is a well-established and profitable way of improving the efficiency of district heating plants and other boilers for wet fuels. However, the condensation is only applicable when the dew point of the flue gas is above the temperature demand for the heating net. The paper industry gives a good illustration of the limitations for conventional condensation: several MW of wet air streams with dew points of 60-65 ̊ C are released but cannot be recovered since the temperature demand is 70-80 ̊ C for the heating net. Different technologies for more advanced waste heat recovery are developing and this report is evaluating a demonstration plant for “hygroscopic condenser”, which uses a hygroscopic solution that allows condensation above the dew point. The hygroscopic solution is potassium formate, which enables condensation to start about 20 ̊ C above the dew point and is sufficiently non-toxic and non-corrosive. The objective of this work is to evaluate both the equipment and the process during some initial tests at the paper mill at Holmen, Braviken. The aim is also to suggest improvements of the process, the components and the additional equipment for future continuous operation. The equipment consists of two main parts: a hygroscopic absorption stage and a regeneration stage. The major part of the humid air is led into an absorption column where vapor is absorbed by the formate solution and rises its temperature. This recovered waste heat is transferred to the heating net by a plate heat exchanger. The regeneration unit is used to maintain the hygroscopic concentrations by evaporation of vapor from the formate solution (amount of absorbed vapor = amount of evaporated vapor). The regenerator is driven by process steam from the existing 3.5 bar net. The evaporated vapor is led to a conventional condenser where the regeneration energy can be recovered and the condensate is bled off. The recovered heat from the process (hygroscopic absorber + regeneration condenser) is used in the heating net at Holmen, Braviken (VVG-net). The initial tests have been made during 15 hours of initial operation, when the equipment has delivered about 3 MWh in total. The tests show a good temperature performance since the dew point of the humid air has been lowered from about 60oC to 47oC. The recovered heat was used for heating from 65oC to about 80oC. During the initial tests the capacity has not yet reached the design values. As an example the delivered heat was measured to 280 kW whereof 46kW from absorbed vapor, 129 kW from the sensible heat in the incoming humid air and 105 kW from the regeneration. The bottle-neck parts of the equipment have been localized and will be overseen during the summer of 2011 and the process is planned to be in use during the autumn with an output capacity of 500kW. The coefficient of performance (COP) is calculated to just below 2 during normal operation but was about 2.7 in the test runs due to the high portion of sensible heat. [1]Förekomst av industriellt spillvärme vid låga temperaturer, Ingrid Nyström, Per-Åke Franck, Industriell Energianalys AB, 2002-04-15
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Nordtvedt, Stein Rune. "Experimental and theoretical study of a compression/absorption heat pump with ammonia/water as working fluid." Doctoral thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for energi- og prosessteknikk, 2005. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-5493.
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Ranger, Pascal-Marie. "La rectification inverse appliquée aux pompes à chaleur à absorption pour valorisation d'effluents thermiques industriels." Vandoeuvre-les-Nancy, INPL, 1993. http://www.theses.fr/1993INPL081N.
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La présente étude concerne la modélisation et l'expérimentation d'un absorbeur pour pompe à chaleur à absorption (PAC). L'étude critique de l'utilisation de l'énergie dans les industries a permis de mettre en évidence l'intérêt d'une PAC à absorption pour la revalorisation des énergies industrielles. L'analyse des inconvénients et des avantages des mélangeurs de PAC à absorption existantes a permis de dégager les principes originaux d'un absorbeur opérant par rectification inverse. Deux types de modèles simples ont été développés pour permettre l'étude des diverses structures possibles pour un tel mélangeur, et celle d'une PAC obtenues par l'adjonction d'une colonne de rectification directe a un mélangeur opérant par rectification inverse. Les résultats expérimentaux obtenus sur une colonne de rectification inverse fonctionnant soit avec le couple acétone-eau, soit avec le couple eau-glycol, ont permis de confirmer la faisabilité d'un tel absorbeur, et de montrer l'intérêt d'un préchauffage de la solution pauvre pour l'obtention de hautes températures. Des températures de revalorisation supérieures à 160c ont pu être obtenues sur l'installation expérimentale
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Priedeman, Douglas Kelly. "Testing of a residential GAX absorption heat pump and chiller and verification of a computer cycle simulation /." The Ohio State University, 1997. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487948440827071.
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Oluleye, Oluwagbemisola Olarinde. "Integration of waste heat recovery in process sites." Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/integration-of-waste-heat-recovery-in-process-sites(ebbc2669-2c9b-40be-9eae-8d2252f0286f).html.
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Exploitation of waste heat could achieve economic and environmental benefits, while at the same time increase energy efficiency in process sites. Diverse commercialised technologies exist to recover useful energy from waste heat. In addition, there are multiple on-site and offsite end-uses of recovered energy. The challenge is to find the optimal mix of technologies and end-uses of recovered energy taking into account the quantity and quality of waste heat sources, interactions with interconnected systems and constraints on capital investment. Explicit models for waste heat recovery technologies that are easily embedded within appropriate process synthesis frameworks are proposed in this work. A novel screening tool is also proposed to guide selection of technology options. The screening tool considers the deviation of the actual performance from the ideal performance of technologies, where the actual performance takes into account irreversibilities due to finite temperature heat transfer. Results from applying the screening tool show that better temperature matching between heat sources and technologies reduces the energy quality degradation during the conversion process. A ranking criterion is also proposed to evaluate end-uses of recovered energy. Applying the ranking criterion shows the use to which energy recovered from waste heat is put determines the economics and potential to reduce CO2 emissions when waste heat recovery is integrated in process sites. This thesis also proposes a novel methodological framework based on graphical and optimization techniques to integrate waste heat recovery into existing process sites. The graphical techniques are shown to provide useful insights into the features of a good solution and assess the potential in industrial waste heat prior to detailed design. The optimization model allows systematic selection and combination of waste heat source streams, selection of technology options, technology working fluids, and exploitation of interactions with interconnected systems. The optimization problem is formulated as a Mixed Integer Linear Program, solved using the branch-and-bound algorithm. The objective is to maximize the economic potential considering capital investment, maintenance costs and operating costs of the selected waste heat recovery technologies. The methodology is applied to industrial case studies. Results indicate that combining waste heat recovery options yield additional increases in efficiency, reductions in CO2 emissions and costs. The case study also demonstrates that significant benefits from waste heat utilization can be achieved when interactions with interconnected systems are considered simultaneously. The thesis shows that the methodology has potential to identify, screen, select and combine waste heat recovery options for process sites. Results suggest that recovery of waste heat can improve the energy security of process sites and global energy security through the conservation of fuel and reduction in CO2 emissions and costs. The methodological framework can inform integration of waste heat recovery in the process industries and formulation of public policies on industrial waste heat utilization.
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Kürthy, Marián. "Kogenerační jednotka s absorpčním TČ." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2012. http://www.nusl.cz/ntk/nusl-230314.
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This diploma work aims to evaluate the functional connection of the cogeneration unit with an internal combustion engine and an absorption heat pump to increase the heating effect of the cogeneration. The aim of this work is to design a functional system and evaluate it from the technical - economic terms. In the introduction of the theoretical work the applied cogeneration technologies used in combined heat and power production are presented. Then there is described the principle of heat pumps, their basic components and theoretical comparison of compression and absorption heat pumps. In the practical part of this work is for a specific application in the area Technická 2 proposed merger of the cogeneration unit with an internal combustion engine and an absorption heat pump, while detailed design parameters used in absorption heat circulation are set. At the end of this paper there are designed various heat exchangers of applied absorption heat pump. The final part of the work is devoted to technical - economic assessment of applied design. In this assestment three different types of heat pumps are compared: Absorption heat pump with working solution H2O-LiBR, absorption heat pump with working fluids NH3-H2O and compressor heat pump.
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Chan, Keng Wai. "Measurement and analysis of bubble pump and Einstein-Szilard single pressure absorption refrigeration system." Thesis, University of Oxford, 2011. http://ora.ox.ac.uk/objects/uuid:f10706c5-6952-4c50-9aef-065f1627a19b.
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The increasing demand for the domestic refrigeration system urges the development of greener form of refrigeration. The eighty-year-old single pressure absorption refrigeration system invented by Albert Einstein and Leo Szilard is attractive as it has no mechanical moving parts and can be driven by heat alone. However, the literature on either the refrigeration system or its components is scarce. The bubble pump is the crucial component of the refrigeration system, but it is poorly understood as its mass flow rate cannot be readily predicted. Two new time correlations in the mass flow rate prediction are presented to increase the accuracy when heat losses occur in the bubble pump. These time correlations are verified with the experimental results. When either the heat input or submergence ratio increases, the accuracy of the prediction increases. The percentage of error for the high heat input or submergence ratio is within ±10%. Working conditions and system dimension have a direct influence to the bubble pump performance. For instance, the bubble pump experimental results show that the mass flow rate of the bubble pump increases when either the submergence ratio or the concentration of ammonia increases. However, the performance of the bubble pump drops when the tube diameter or the system pressure increases. The Einstein refrigeration system has only been rebuilt once since it invention. In order to redesign and rebuilt a practical Einstein refrigeration system, some challenges are revealed. With the combination of the good features of the designs of Einstein and Delano, a new prototype has been rebuilt and tested. The practical results obtained from the five experimental setups are the first set of experimental result that has ever been presented. The highest cooling capacity and coefficient of performance (COP) obtained are 5 W and 0.04 respectively.
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Blackman, Corey. "Investigation of the performance of individual sorption components of a novel thermally driven heat pump for solar applications." Thesis, KTH, Tillämpad termodynamik och kylteknik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-149877.
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An enhanced-modularity thermally driven chemical heat pump was conceptualised as a second generation product for various heating and cooling applications with special emphasis on solar applications. The typical characteristics of the absorption heat pump were studied and the key performance parameters were selected for further investigation. An experimental test rig was constructed to allow for the testing of each component’s performance characteristics with special attention being paid to the ability to interchange components to test various configurations as well as to the facilitation of standardised relatively rapid testing. The heat transfer coefficient of the condenser/evaporator was found to be between 260 and 300 W/m2-°C during evaporation and between 130 and 170 W/m2-°C during condensation. Salt type has major impact on the system’s cooling power and cooling energy with the LiBr and water sorption pair having a 62% higher cooling/heating power than LiCl with the same matrix type and thickness. Matrix types and sorption pairs were compared with regards to the principal parameters of power and energy density with results ranging from 60 to 163 Wh/litre. The final section of the study tackled the theoretical foundation behind the system processes with modelling and simulation of the processes and comparison with the experimental data. The model makes the foundation of the continuous development of a more detailed and accurate physical model to enhance the design and optimisation process of the system.
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Noubli, Halima. "Développement d’un nouveau thermo-transformateur à absorption-démixtion : optimisation conjointe du cycle et du mélange de travail." Thesis, Vandoeuvre-les-Nancy, INPL, 2010. http://www.theses.fr/2010INPL089N/document.
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Ce travail porte sur l’étude d’un nouveau type de thermo-transformateur à absorption-démixtion (TTAD) utilisant un mélange présentant une lacune de miscibilité à basse température. Dans ce cycle, l’opération de séparation, est effectuée par décantation gravitaire par simple refroidissement du mélange. La séparation est ainsi énergétiquement gratuite et permet d’atteindre des rendements thermiques plus élevés que ceux des pompes à chaleur à absorption classiques dans lesquelles la séparation s’effectue par distillation.Afin de trouver des mélanges de travail pour atteindre un saut thermique de 50°C, un outil de simulation numérique a été développé pour évaluer les performances des TTAD en fonction des conditions opératoires (rapport d’alimentation et nombre d’étages de la colonne de rectification inverse) et des caractéristiques des composés du mélange de travail (Cp, Lv, paramètres caractéristiques des équilibres liquide-liquide et liquide-vapeur). L’optimisation des conditions opératoires a ainsi permis d’obtenir un saut thermique maximal de 12,4°C pour le mélange n-heptane / DMF pris comme référence. En faisant varier les propriétés des composés autour de celles de ce mélange de référence, un saut maximum de 32°C a été calculé pour un mélange fictif. L’étude de 17 mélanges réels a permis atteindre 21°C de saut thermique. Une liste d’autres mélanges à étudier a été établie. A l’aide d’une unité pilote d’une puissance de 4kW, des mesures expérimentales des performances du cycle modifié de TTAD pour le mélange n-heptane / DMF ont été réalisées et démontré la faisabilité de ce cycle même si le saut thermique de 11°C atteint au maximum est inférieur à celui calculé par simulationThis work is a study of a new type of Absorption-Demixing Heat Transformer (ADHT), using a mixture exhibiting a miscibility gap at low temperature. In this cycle, the separation step is performed by settling obtained after cooling the mixture. The separation is then energetically free and enables to reach thermal yields higher than those obtained for classical absorption heat transformers where separation is done by distillation.In order to find suitable working mixtures to reach temperature lift of 50°C, a numerical simulation tool was developed to calculate ADHT performances. This tool enabled to calculate thermal yield and thermal lift for different values of operating parameters (molar feed ratio, number of stages of rectification column) and different properties of working mixtures (Cp, Lv, parameters characterizing liquid-liquid and liquid-vapour equilibria). The best operating conditions allowed reaching a 12,4°C thermal lift for the n-heptane / DMF mixture takes as a reference mixture. By varying the mixture properties around the values of the reference mixture properties, a maximal thermal lift of 32°C was reached for an imaginary mixture. 17 real mixtures were also studied and enabled to reach a 21°C temperature lift. A list of other working mixtures that should be suitable was established. A 4 kW ADHT pilot unit was designed and built. The technical feasibility of this cycle was then experimentally demonstrated with this unit. A maximum temperature lift of 11°C was measured with the n-heptane / DMF mixture that is lower than the values calculated by simulation
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Veselý, Josef. "Sorpční tepelné čerpadlo." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2016. http://www.nusl.cz/ntk/nusl-241683.
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This thesis deals with the issue of sorption heat pumps. The theoretical part is devoted to a detailed description of the function of adsorption and absorption heat pumps. For a better understanding of the adsorption cycle is computed theoretical thermal cycle and the heating factor of zeolite adsorption heat pump are computed. The practical part is focused on the design absorption heat pump that works in conjunction with a natural gas boiler. The pump is designed for cooling flue gas condensing boiler and the possible use of thermal energy from other low-temperature source. The thesis contains a thermal calculations, engineering design and structural design of the heat pump.
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Torres, Merino Jesús. "Contacteurs gaz-liquide pour pompes à chaleur à absorption multi-étages." Vandoeuvre-les-Nancy, INPL, 1997. http://www.theses.fr/1997INPL017N.
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Le présent travail est une contribution à l'étude des pompes à chaleur à absorption. Nous nous sommes intéressés en particulier à l'hydrodynamique et au transfert de chaleur par la technique du film ruisselant. Cette étude nous a permis de concevoir et développer des nouvelles structures d'évaporateurs et désorbeurs à ailettes spiralées internes et externes en graphite pouvant résister de manière significative à la corrosion des couples de travail utilisés dans des pompes à chaleur à absorption à des températures de l'ordre de 230°C de pressions de l'ordre de 6 à 7 bar. Le premier chapitre présente une analyse bibliographique et une étude expérimentale de l'hydrodynamique d'un film ruisselant sur des contacteurs gaz-liquide de différentes structures. Le deuxième chapitre repose sur une étude expérimentale du transfert de chaleur en échauffement d'un tube en graphite à ailette spiralée externe. Nous comparons notamment ces résultats à ceux des modèles existants. Dans le quatrième chapitre nous abordons la modélisation et le calcul d'une frigopompe utilisant le binaire eau-bromure de lithium. Nous présentons les résultats obtenus en échauffement et en évaporation sur le banc d'essais d'un désorbeur-condenseur qui peut être une des bases pour la conception d'une pompe à chaleur à absorption à trois effets. Enfin dans le cinquième chapitre nous présentons les diagrammes enthalpiques, entropiques et exergétiques calculés pour le couple eau-bromure de lithium qui peuvent être utiles pour une analyse entropique et exergétique des irréversibilités dans les processus de séparation et de mélangeage
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Aranguren, Campos Fabian Alexis. "Využití odpadního tepla kompresorů do soustavy centrálního zásobování teplem pomocí absorpčního tepelného čerpadla." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2020. http://www.nusl.cz/ntk/nusl-433480.
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With the growth of energy consumption and the optimization of industrial processes worldwide, new energy sources have been explored and investigated. Waste heat is a potential source for the generation of electricity and heat. This heat can be reused at different stages of industrial processes by using absorption heat pumps, which transfer thermal energy from a location with a lower thermal potential to a location with a higher thermal potential. This research work is basically focused on the evaluation of different absorption heat pumps implemented in the SAKO Brno incineration plant. To carry out this purpose, a bibliographic review of this technology has been carried out worldwide, then the mass and energy balance in the compressor is presented, from which the waste heat to be recovered with the pump will be obtained. Using the EES software, the mass and energy balance of the selected pumps is performed, then the amount of heat and electrical energy generated by the plant when implementing each of the pumps is shown, and finally the economic analysis is presented The design and implementation of a heat exchanger in the system is also included as an essential part of improving operation. The best option arises from the highest operational efficiency at the lowest possible cost.
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Bednařík, Jakub. "Využití odpadního tepla z technologických procesů." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2018. http://www.nusl.cz/ntk/nusl-376930.
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Master thesis deals with the utilization of waste heat from Nova Mosilana company. Theoretical part of this work is focused on the waste heat description (heat, heat quantity, heat temperature/quality, composition of waste stream) in which a considerable energy potential is hidden. The other parts describe waste heat technology, especially heat pumps, Organic Rankine Cycle (ORC) and system absorption cooling. Some of the technologies described in the theoretical part are used in the design of the more efficient existing waste heat utilization, especifically power and cold production.
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Maghera-Entwistle, R. I. "Intermittently operated chemical heat pump : Slurried absorption systems and an investigation into the performance characteristics of methanolated potassium hydroxide in powdered form using methanol as the working fluid." Thesis, Cranfield University, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.374001.
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Pleva, Ondřej. "Absorpční oběhy v teplárenství." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2019. http://www.nusl.cz/ntk/nusl-401562.
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Goal of this thesis is to introduce technology of absorption heat pumps in various modifications. Technical design draft is created for chosen modification (single stage unit water-LiBr) and based on given parameters calculated in computing software EES (engineering equation solver) and process is explained step-by-step. Following part of thesis contains reference design draft of heat plant and this design is used to demonstrate several different options of applying absorption heat pump including version capable of providing also cooling. Those options are compared with each other from technological and economical stand point.
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Vidlák, David. "Využití absorpčních systémů v teplárenství." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2018. http://www.nusl.cz/ntk/nusl-378742.
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Main goal of this work is familiarization with basic features of absorption heat pumps and it’s growing importance on the market. In the first part of the work there is a research for clarifying facts associated with such pumps. In the introduction there are descriptions of basic information from the field of heating industry and its connections to our systems. Next there is a brief analysis of price changes in electricity and heat in the last five years. Main part of the analytical section is a description of the used absorption system. Second part of the work is focused on the calculation of the absorption system itself. First there is calculated internal and external part of the device according to the parameters from GE Power s.r.o. After this step there are parametric studies based on changes of key parameters of the default device for a demonstration of the behavior of a heating pump. In the end of the work there is a integration of the unit into the heating cycle for variations including flue gas condenser and using a cooling water from the turbine condenser.
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Nasri, Karima. "Frigo pompes à absorption multiétagées de haute performance : simulation et conception d'une maquette expérimentale." Vandoeuvre-les-Nancy, INPL, 1997. http://www.theses.fr/1997INPL054N.
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Ce travail se rapporte à l'étude de pompes à chaleur à absorption multiétagées, dans le but de développer des nouvelles machines frigorifiques de faible puissance pour la climatisation des bâtiments et utilisant la combustion du gaz naturel comme source de chaleur. Ce type de travail fait l'objet d'une demande de plus en plus importante car il s'avère être une solution de substitution intéressante à l'interdiction récente de production et d'utilisation des composés fluorés tels que les CFC (ChloroFluoroCarbures) et les HCFC (HydroChloroFluoroCarbures). Nous proposons donc dans ce travail, des structures de pompes à chaleur à absorption multiétagées pour frigo pompes qui offrent une excellente voie d'amélioration des performances par rapport aux systèmes simples mono-étages. Dans cette étude, nous nous intéressons plus particulièrement à développer les structures multiétagées en parallèle thermique au niveau du mélangeur, et ce pour une production maximale de froid utile. Ce principe nécessite un mélange qui présente un large domaine de travail (en pression et température). Le mélange utilisé dans cette étude est le couple Nh3/H2O de par ses propriétés et les données thermodynamiques le concernant qui sont assez bien connues. Pour améliorer les performances de ces systèmes, nous distinguons deux grandes voies. La première voie consiste à essayer de profiter de ce besoin de rectification, tandis que la seconde voie cherche à éliminer cette rectification.
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Oliveira, Junior Silvio De. "Revalorisation des effluents thermiques industriels : analyse exergétique, entropique et économique." Vandoeuvre-les-Nancy, INPL, 1991. http://docnum.univ-lorraine.fr/public/INPL_T_1991_OLIVEIRA_JUNIOR_S_D.pdf.
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ADans la partie 1, nous développons l'analyse entropique et exergétique des processus de transfert de chaleur et de matière de la séparation et du mélangeage d'un mélange binaire, pour définir les conditions optimales de tels systèmes, qui sont les principaux éléments des machines à absorption. Nous présentons une méthode graphique d'élaboration des bilans d'exergie et de calcul des pertes exergétiques lors d'une séparation/mélangeage d'un mélange binaire. Sont présentes les diagrammes exergie-concentration et exergie-enthalpie pour les couples H2O-LiBr et NH3-H2O. Dans la partie 2, nous présentons de nouvelles configurations de structures de promoteurs de turbulence pour des films ruisselants qui provoquent un mélangeage transversal du film en assurant les conditions de mouillabilité film-paroi et ayant des bonnes performances thermiques et des faibles couts de fabrication. L’évaluation du comportement de ces structures est faite à partir de la comparaison de leurs coefficients de transfert de chaleur et de la production spécifique globale d'entropie avec un tube lisse ayant la même géométrie et sous les mêmes conditions d'opération. Dans la partie 3, nous présentons de nouvelles structures et des nouveaux types de thermotransformateurs et frigo-pompes pour la revalorisation des effluents thermiques industriels. Ce sont deux systèmes à absorption pure et deux systèmes hybrides à absorption-compression mécanique et absorption-ejecto-compression. Nous développons une méthode d'analyse exergo-économique de ces systèmes basés sur une fonction de valeur technico-économique qui caractérise la performance combinée thermique et économique des systèmes. Les performances de ces systèmes sont comparées dans des conditions d'opération industrielles à travers l'emploi des logiciels PACA-design. Pour chaque condition d'opération nous identifions les systèmes les plus performants en utilisant la fonction de valeur technico-économique
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Larnaudie, Guy. "Etude thermodynamique de fluides de travail pour pompes à chaleur fonctionnant à très hautes températures. Utilisation du mélange mercure-sodium." Rouen, 1996. http://www.theses.fr/1996ROUES010.
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L'utilisation de pompes à chaleur fonctionnant à très hautes températures permettrait de pallier au déficit de chaleur à haut niveau (500°C) très souvent constaté sur les grandes installations industrielles qui, par contre, présentent généralement un excédent de chaleur à bas niveau (200°C). Les travaux présentés dans ce mémoire s'inscrivent dans le cadre d'une étude des pompes à chaleur à absorption susceptibles d'être utilisées dans le domaine des températures comprises entre 200°C et 1 200°C ; ceci au moyen de fluides de travail constitués d'un mélange de métaux liquides ou de sels fondus et, plus particulièrement, des mélanges mercure-sodium et trichlorure d'aluminium-chlorure de sodium. Pour chaque système, les propriétés physico-chimiques ont été estimées et l'équilibre liquide-vapeur a été décrit à l'aide de modèles thermodynamiques. Dans le cas du système mercure-sodium, ce modèle a été validé à l'aide des mesures de pression de vapeur réalisées sur une installation pilote. Associés aux bilans de matière et d'énergie établis dans le cas d'une pompe à chaleur idéale, ces modèles ont permis de déterminer, en fonction des conditions de fonctionnement (température, pression,. . . ) Les coefficients de performance de tels thermotransformateurs. La désorption du mercure, par ébullition nucléée d'amalgames de sodium, a été étudiée au moyen d'expériences spécifiques et, dans l'optique du dimensionnement de prototypes, les coefficients de transfert de chaleur ont été déterminés. Plusieurs projets de pompes à chaleur, à caractère expérimental ou industriel, sont proposés. Ces derniers utilisent le système mercure-sodium et leurs coefficients de performance théoriques sont compris entre 1,5 et 1,9.
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Lasalle, Alain. "Analyse exergétique des procèdes de séparation-mélangeage : application aux pompes à chaleur à absorption et l'adsorption modulée en pression (PSA)." Vandoeuvre-les-Nancy, INPL, 1995. http://www.theses.fr/1995INPL104N.
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La présente étude concerne l'étude exergétique des pompes à chaleur à absorption opérant par rectification inverse et des opérations d'adsorption modulée en pression. L’étude du diagramme température-enthalpie permet de mettre en évidence l'intérêt des divers types de pompe à chaleur à absorption présentes. L’analyse exergétique de la distillation permet de déterminer un optimum opératoire dépendant des conditions thermodynamiques du flux d'alimentation à séparer. La représentation d'un cycle de séparation - mélangeage sur un ensemble de diagrammes thermodynamiques permet de distinguer et de mesurer les flux de matière, d'enthalpie et d'exergie traversant le système. Sachant que la chaleur latente d'évaporation de tout corps pur s'annule au point critique, la réduction à zéro de la chaleur couteuse à fournir au système permet d'obtenir un coefficient de performance élevé. Comme pour la distillation, l'analyse exergétique des opérations d'adsorption modulée en pression permet de déterminer un optimum opératoire, montrant ainsi l'intérêt d'une telle approche
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Свинухін, О. М. "Дослідження та проектування абсорбційного теплового насосу для потреб системи гарячого водопостачання." Master's thesis, Сумський державний університет, 2019. http://essuir.sumdu.edu.ua/handle/123456789/76507.
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Розділ 1 "Спеціальний розділ": загальні відомості про теплонасосні установки, переваги та недоліки абсорбційних теплових насосів, розрахунок теплових потоків бромисто-літієвого підвищуючого термотрансформатора, розрахунок теплових потоків хлористого-літієвого підвищуючого термотрансформатора, розрахунок рідко-кільцевого вакуумного насосу, розрахунок горизонтального кожухотрубного зрошувального абсорбера, розрахунок горизонтального кожухотрубного затопленого генератора; розділ 2 «Економічний розділ»: розрахунок матеріальних витрат, визначення оптової ціни, розрахунок капітальних і експлуатаційних витрат споживача; розділ 3 «Охорона праці та безпека у надзвичайних ситуаціях»Раздел 1 "Специальный раздел": общие сведения о теплонасосные установки, преимущества и недостатки абсорбционных тепловых насосов, расчет тепловых потоков бромисто-литиевого повышающего термотрансформатора, расчет тепловых потоков хлористого-литиевого повышающего термотрансформатора, расчет жидко-кольцевого вакуумного насоса, расчет горизонтального кожухотрубного оросительного абсорбера расчет горизонтального кожухотрубного затопленного генератора; раздел 2 «Экономический раздел»: расчет материальных затрат, определение оптовой цены, расчет капитальных и эксплуатационных затрат потребителя; раздел 3 «Охрана труда и безопасность в чрезвычайных ситуациях»
Section 1 "Special Section": general information about heat pump installations, advantages and disadvantages of absorption heat pumps, calculation of heat fluxes of lithium bromide boost thermal transformer, calculation of heat fluxes of lithium chloride lithium boost thermal transformer, calculation of a liquid ring vacuum pump, calculation of a horizontal shell-and-tube irrigation absorber calculation of a horizontal shell-and-tube flooded generator; section 2 “Economic section”: calculation of material costs, determination of the wholesale price, calculation of capital and operating costs of the consumer; Section 3 “Occupational Safety and Security”
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Wong, Choong Wah. "An absorption recompression system." Thesis, University of Nottingham, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.320018.
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Nilsson, Martin. "Expansionsmaskiner istället för strypventiler - en effektivisering." Thesis, Uppsala universitet, Institutionen för fysik och astronomi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-146322.
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In Uppsala CHP Plant, there are six pressure reducing valves to reduce the pressure from 15 to 3 bars, before six absorption heat pumps. During the process the energy is conserved but losses occur in form of exergy. The aim of this thesis is to reduce the losses of exergy. This can be done by letting turbines replace the pressure reducing valves. In this thesis an investigation has been done of the conditions today, the conditions after the change from pressure reducing valves to turbines and a comparison of three different types of turbine solutions. The three examined solutions are one turbine, several helical screw expanders and several small turbines in parallel with asynchronous generators. The six absorption heat pumps have been divided into two groups; one group of four and one group of two absorption heat pumps. An investigation of locations and space in nearby switchgears has been done for each group. Contacts with retailers of the examined turbine solutions have been taken to gather technical specifications. These technical specifications have been used to simulate the electricity production and the economical yield of each type of examined solution. The investigation shows that the best solution is the solution with several small turbines with asynchronous generators. It has lower investment cost (15 [MSEK]) and the best yield. The proposed solutions will have an installed capacity of 2.65 [MW] to a cost of 5 601 [SEK/kW]. The electric energy production will be 15.7 [GWh/year]. An investment is recommended to a future electric energy price around 400 [SEK/MWh]. Before an investment it is recommended to investigate how to optimize the regulation of the new system with absorptions heat pumps and turbines.
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James, Simon. "A new working fluid ’potassium formate’ for use in absorption heat pumps." Thesis, University of Nottingham, 1998. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.759768.
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White, S. D. "Design and modelling of novel absorption refrigeration cycles /." Title page, contents and summary only, 1993. http://web4.library.adelaide.edu.au/theses/09PH/09phw5878.pdf.
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Nagavarapu, Ananda Krishna. "Binary fluid heat and mass exchange at the microscale in internal and external ammonia-water absorption." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/45777.
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Absorption space-conditioning systems are environmentally benign alternatives to vapor compression systems and have the capability of being driven by waste heat. However, a lack of practically feasible and economically viable compact heat and mass exchangers is a major limitation in the success of this technology. The viability of the absorption cycle depends upon the performance of the absorber, which experiences large heat and mass transfer resistances due to adverse temperature and concentration gradients during the phase change of the binary mixture working fluid, resulting in large overall component sizes. Understanding of the coupled heat and mass transfer during binary fluid mixture absorption at the microscales is critical for the miniaturization of these components, which will enable broad implementation of this technology.
The proposed study aims to achieve this by investigating ammonia-water absorption for two distinct flow configurations: external falling films and internal convective flows. For the falling-film absorption case, ammonia-water solution flows around an array of small diameter coolant tubes while absorbing vapor. This absorber is installed in a test facility comprising all components of a single-effect absorption chiller to provide realistic operating conditions at the absorber. Local temperature, pressure, and flow measurements will be taken over a wide range of operating conditions and analyzed to develop a heat and mass transfer model for falling-film ammonia-water absorption. A microscale convective flow absorber will also be investigated. This absorber consists of an array of parallel, aligned alternating shims with integral microscale features, enclosed between cover plates. These microscale features facilitate flow of various fluid streams and the associated heat and mass transfer. The use of microchannels induces high heat and mass transfer rates without any active or passive surface enhancement. The microscale absorber for small-scale applications will be evaluated over a wide range of operating conditions on a single-effect absorption heat pump breadboard test facility. The study will conclude with a comparison of the two flow configurations for absorption, with recommendations for their application in future miniaturization efforts
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Li, Yong, and 李勇. "Performance prediction model for a rotary multi-bed adsorption coolingsystem." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2004. http://hub.hku.hk/bib/B31245742.
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Arango, Munoz Paty. "Stripper Modification of a Standard MEA Process for Heat Integration with a Pulp Mill." Thesis, KTH, Kemiteknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-289162.
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De 20 största massabruken i Sverige släpper tillsammans ut ungefär 20 miljoner ton CO2 per år. Dessa utsläpp har biogent ursprung och anses därför vara klimatneutrala. Massa- och pappersindustrin är därmed en lämplig kandidat för implementeringen av BECCS (eng. Bioenergy with Carbon Capture and Storage) och har en betydande potential att nå de, av den svenska regeringen, uppsatta klimatmålen som säger att Sverige inte ska några nettoutsläpp av växthusgaser till atmosfären senast år 2045. I detta examensarbete simulerades kemiska absorptions- och desorptionsprocesser med MEA som lösningsmedel genom att tillämpa den hastighetsbaserade metoden i en rigorös modell i Aspen Plus. Stripper- och absorptionsmodellerna validerades innan standardprocessen modifierades till en konfiguration som möjliggör värmeintegration av koldioxidinfångningens överskottsvärme med, exempelvis, ett sulfatmassabruk. Avskiljningsgraden och laddning hos den mättade lösningen användes som prestandaindikatorer för att validera absorptionskolonnerna. Återkokarens energiåtgång och laddning hos den omättade lösningen användes somprestandaindikatorer för att validera stripperkolonnerna. Samtliga kolonner dimensionerades för att erhålla 90 vikt% avskiljningsgrad. Olika flödeshastigheter av lösningsmedlet testades för att säkerställa effektivt nyttjande av packningen i absorptions- och stripperkolonnerna. Lämpliga temperaturnivåer för värmeintegration, inom och utanför, koldioxidinfångningen erhölls genom att utvärdera olika varianter av en stripper-overhead-kompression konfiguration. Utvärderingen av den modifierade MEA processen tog hänsyn till potentialen för ångbesparing och energieffektivisering. Resultat från simuleringarna tyder på att den modifierade strippern skulle kunna ge besparingar på upp emot 11 % i ånganvändning. Energibesparingar i samma storleksordning kunde även erhållas genom värmeintegration mellan koldioxidinfångningen och en särskild process i ett referensbruk. Implementering av BECCS-konceptet på det här sättet skulle därmed kunna bli ett mer attraktivt alternativ för den svenska massa- och pappersindustrin att bekämpa klimatförändringarna.The 20 largest pulp mills in Sweden emit around 20 million tonnes of CO2 per year. These emissions are considered carbon-neutral since they originate from biogenic sources. The pulp and paper industry is therefore a good candidate for the application of BECCS (Bioenergy with Carbon Capture and Storage) and has the potential to play a significant role for reaching the long-term mitigation target set by the Swedish government that Sweden should be climate-neutral by year 2045. In this thesis, a MEA-based chemical absorption and desorption process was rigorously modelled in Aspen Plus using the rate-based method. Validation of the absorber and stripper model was conducted before the standard process was modified to a configuration that enables heat integration of a significant amount of excess heat from the capture process in, for example, a Kraft pulp mill. CO2 removal rate and rich solvent loading were used as performance indicators to validate the absorber columns. The reboiler duty and lean solvent loading served as performance indicators in the stripper validation. The columns were dimensioned considering 90 wt% capture rate. Efficient use of the entire packing in the absorber and stripper columns was ensured by testing different solvent flow rates. Suitable temperature levels for heat integration, within and across the capture plant, were obtained through an assessment of different versions of a stripper overhead compression configuration. The evaluation of the modified MEA processes took into account the steam conservation potential and energy efficiency potential. The simulation results indicate that the modified stripper may lead to savings of up to 11% in steam consumption. Heat integration between the capture plant and a specific process in a reference Kraft pulp mill resulted in energy savings of the same order of magnitude. Thereby, making the BECCS concept a more attractive solution for the Swedish pulp and paper industry to mitigate climate change.
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Bohra, Lalit Kumar. "Analysis of Binary Fluid Heat and Mass Transfer in Ammonia-Water Absorption." Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/19780.
Full textAbstract:
An investigation of binary fluid heat and mass transfer in ammonia-water absorption was conducted. Experiments were conducted on a horizontal-tube falling-film absorber consisting of four columns of six 9.5 mm (3/8 in) nominal OD, 0.292 m (11.5 in) long tubes, installed in an absorption heat pump. Measurements were recorded at both system and local levels within the absorber for a wide range of operating conditions (nominally, desorber solution outlet concentrations of 5 - 40% for three nominal absorber pressures of 150, 345 and 500 kPa, for solution flow rates of 0.019 - 0.034 kg/s.). Local measurements were supplemented by high-speed, high-resolution visualization of the flow over the tube banks. Using the measurements and observations from videos, heat and mass transfer rates, heat and vapor mass transfer coefficients for each test condition were determined at the component and local levels.
For the range of experiments conducted, the overall film heat transfer coefficient varied from 923 to 2857 W/m2-K while the vapor and liquid mass transfer coefficients varied from 0.0026 to 0.25 m/s and from 5.51×10-6 to 3.31×10-5 m/s, respectively. Local measurements and insights from the video frames were used to obtain the contributions of falling-film and droplet modes to the total absorption rates. The local heat transfer coefficients varied from 78 to 6116 W/m2-K, while the local vapor and liquid mass transfer coefficients varied from -0.04 to 2.8 m/s and from -3.59×10-5 (indicating local desorption in some cases) to 8.96×10-5 m/s, respectively. The heat transfer coefficient was found to increase with solution Reynolds number, while the mass transfer coefficient was found to be primarily determined by the vapor and solution properties. Based on the observed trends, correlations were developed to predict heat and mass transfer coefficients valid for the range of experimental conditions tested. These correlations can be used to design horizontal tube falling-film absorbers for ammonia-water absorption systems.
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陳柏岳. "Performance Analysis of Ammonia-Water Absorption Heat Pump Systems." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/22856439181230877584.
Full textAbstract:
碩士國立臺北科技大學
冷凍與低溫科技研究所
90
This research aims at the investigation of possible influences that ammonia-water Absorption Refrigeration system have on the COP under different conditions of operation. To establish the complete theory of the absorption system this research starts from elaborate description of types of Absorption Refrigeration system and components. Then, on the basis of thermodynamic theory, the author sets up the mathematic formula and restrictions. Finally, to achieve the best operation condition, all possible circulation system will be simulated by making use of ABSIM . The research indicat that COP changes with the variation of surrounding temperature. The COP is 1.2231 when the temperature of absorber and condenser rise to 100[℉] ; COP falls to 0.653 when it rises to 130[℉]. COP also varies with temperature as SGAX system is applied for heating circulation. The COP is 1.718 when the temperature of the outlet temperature of evaporator reaches 25[℉] ; COP, 2.297,when the temperature is as high as 65[℉]. As for the influens of SGAX flow rate on COP, the research indicates that the system achieve the best COP when SGAX flow rate gets to 6.0 [lb/min]. COP drops radically with the reduction of flow rate. When it is below this point. COP drops slowly when flow rate gets higher then this point. The best SGAX flow rate varies under different operating conditions. WGAX indicat that COPa changes with the variation of waste heat recovery. The COPa is 0.998 when the waste of temperature of 270[℉] ; COPa rise to 1.253 when it rises to 390[℉]. Under steady-state condition, increasing Generator temperature (Tg) and Evaporator temperature (Te) or decreasing Condenser temperature (Tc) and Absorber temperature (Ta) seemed to promote the COP effectively.
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鄭進山. "Study on the absorption model and solvent extraction of an absorption heat pump." Thesis, 1987. http://ndltd.ncl.edu.tw/handle/27827271861697776723.
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Chou, Te Ming, and 周德明. "Heat and Mass Transfer in Falling Film Absorption Process for Cooling and Heat Pump System." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/56579227688824439864.
Full textAbstract:
博士國立中山大學
機械工程研究所
84
D 滑落薄膜吸收過程 (Falling Film Absorption Process)在工程上逐 漸受到重視，特別是應用於吸收式冷凍空調系統上，因此本文選取氯化鋰 水溶液做為工作流體(吸 收 劑)，研究當吸收器中吸收劑液體薄膜沿著垂 直管壁滑落時，其對周圍水蒸汽(被吸收物)吸收過程的耦合熱質傳效應 。 本文在研究上將分成兩部分，一是波狀 (Wavy Flow)薄膜流，將採用 Collocation Method (Spectral Method)所解出流動方程式的速度場，假 設此波狀流為一週期波，沿光滑管壁垂直滑落，並將所得結果與平滑薄膜 流(Smooth film) 吸收過程作一比較。二是多孔材質部分，則採用 Darcy -Forchheimer-Brinkman 理論模式及配合實驗方法，研究多孔材質 在不同的孔隙率及熱傳導係數時，對水蒸汽質量吸收率的影響，並和波狀 薄膜流的結果做一比較。 從研究結果發現，波狀流吸收過程之熱質 傳效應均較平滑流吸收過程為佳，而使用多孔材質吸收器的熱質傳效應， 在較高的吸收劑流率 (即Re數) 時，也比平滑流為佳。且在本文研究範圍 中可知，熱質傳效應會隨著吸收劑流率及蒸發器水蒸汽壓的升高而增加， 但會隨著不可吸收氣濃度的增高而減少。本研究是以提升吸收器性能作為 研究重點，並藉由數值解析及實驗方法，探討不同變數對吸收器性能的影 響，以期將研究所得結果，作為日後設計吸收式熱泵或冷凍空調系統時的 重要參考依據。
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Lin, Yi-Tai, and 林儀泰. "Thermalefficiency Analyses of LiBr/H2O Absorption Heat Pump Systems with Exhaust Heat of Fuel Cell System." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/96111027699752842674.
Full textAbstract:
碩士國立臺北科技大學
冷凍與低溫科技研究所
91
This thesis concentrates on the thermalefficiency analyses of LiBr/H2O Absorption Heat Pump systems with exhaust heat from Fuel Cell system at various operating conditions that affect the system various performances. The overall concept of exhaust heat utilization for fuel cell can be established and combined with the Absorption Heat Pump systems. In the study, firstly is an introduction of the fuel cell category and characteristic as well as waste Heat utilization. Secondly is the description of types of Absorption circulating system and main component function, and according to the thermalefficiency analyses to create the system cycle mathematic model and restrict conditions of individual component. According to the heat transfer properties of LiBr/H2O working fluid to develop the state equations and simulation of the Absorption chiller at different model of system cycle to get the system optimum operating conditions. Finally applies the EES (Engineering Equation Solver) program to simulate the Fuel Cell loading vs. cooling water various temperatures at different operating conditions. It gets the loading variation of fuel cell from 0~50 kW (at partial operating) and fuel cell output is fixed at 50 kW. Changing the cooling water temperature of Absorption Heat Pump system from 25℃ to 35℃ which also affect the Absorption Heat Pump system performance. It is verified in the study that the recovered energy from the fuel cell exhaust has clearly related with fuel cell power output. The power output has a minimum value at the half load. To improve the Heat Pump system performance and get better recovered energy for system performance, those are required to operate at full load as an optimum condition. On the other hand, low cooling water temperature for fuel cell recovered energy connects with the AHP (Absorption Heat Pump) system can obtain a better performance and recovered heat. For heating purpose of AHT (Absorption Heat Transformer) system, the higher cooling water temperature can increase COP value. However, the decreased heat recovery energy will indirectly affect the fuel cell operating temperature, and change the fuel cell power production efficiency. This subject needs to be further discussed by a separated paper.
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Hsu, Chih-Chen, and 許志成. "Performance Evaluation of Direct-Driven Hydrogen Energy SOFC Using Exhaust Heat of Absorption Heat Pump Systems." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/8f44gw.
Full textAbstract:
碩士國立臺北科技大學
能源與冷凍空調工程系碩士班
98
As the current rapid development of new high-tech industrial countries, more and more energy consumption required for reducing the global warming effect, echoing the trend of environmental protection by increasing carbon energy, so many advanced countries make high-efficiency low-pollution alternative energy to replace oil make use, in which fuel cells used in power generation of the most attention, because of high temperature fuel cell with high capacity, high efficiency and other main features. This study examines the direct hydrogen fuel supply for the different solid oxide fuel cell system, fuel supply, the SOFC type fuel cell, the use of absorption heat pump with the performance benefits, provide different series of applications enabling the design of the time reference. Another use of hydrogen fuel for solid oxide fuel cell system, the system efficiency and operation parameters can be used for residential buildings is a typical benefit analysis, and try to use the system to compare the performance difference, and according to the first and second laws of thermodynamics analyze the efficiency of the system for the hydrogen and fuel cell power generation efficiency, and finally compare the application of technologies related to the concluding comments.