Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 25 for “"coefficient of performance (COP)"”.
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Design and development of a novel liquid desiccant air-conditioning system
… rapidly and incumbent direct-expansion system performance is poor. Unlike other LDAC systems, DECAL is modular. This allows the indoor hardware to remain small and non-intrusive, and offers increased flexibility to install the system in existing building stock without costly changes to the …
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Processes Involving Acid Gas Solubility In Room Temperature Ionic Liquids (RTILs)
The literature contains a number of thermodynamic studies involving the solubility of acid gases in RTILs. This thesis looks at using these studies in the context of two processes: membrane separation and absorption refrigeration cycles. The first part of this study investigated the separation of a …
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Refrigerant charge reduction in small commercial refrigeration systems
This paper presents analysis of location of refrigerant inventory and numerical results of charge reduction in a typical bottle cooler. The original unit was first characterized by determining its capacity, the coefficient of performance (COP), pull-down characteristics, and total charge using …
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Improvements on performance of a heat pump water heater system
… friendly nature with low energy consumption. The Coefficient of Performance (COP) of the HPWH can be influenced by multiple factors: ambient temperature, relative humidity, hot water usage profile, the size and shape of heat exchangers (evaporator and condenser), type and shape of compressor, …
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Proposed Design for a Coupled Ground-Source Heat Pump/Energy Recovery Ventilator System to Reduce Building Energy Demand
… thesis focuses on reducing the energy demand of a residential building by using a coupled ground-source heat pump/energy recovery ventilation (GSHP-ERV) system to present a novel approach to space condition and domestic hot water supply for a residence. The proposed system is capable of …
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Potentials for COP increase in vapor compression systems
… presents an experimental and numerical study of three different opportunities for COP increase in vapor compression systems: work recovery ejectors, condenser subcooling and increase of relative size of heat exchangers (HXs). Regarding work recovery ejectors, experimental results showed that …
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Modeling and design of a power boosted turbo-compression cooling system
… challenges through the modeling and design of a volume optimized turbo-compression cooling system (TCCS). The TCCS is driven by low-grade waste heat in the shipboard diesel generator set jacket water and lubrication oil and was designed to be a drop-in replacement of electric chiller …
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Experimental and Analytical Investigation of a Two-Phase Ejector Used for Expansion Work Recovery in a Transcritical R744 Air-Conditioning System
Although the reduced cooling capacity and coefficient of performance (COP) at elevated outdoor temperatures represent an inherent drawback of the transcritical carbon dioxide (CO2, R744) refrigeration cycle, the supercritical heat rejection pressure can be used to maximize the system performance. …
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Electrocaloric applications based on multilayer capacitors of PbSc₀.₅Ta₀.₅O₃
… refrigerators and heat pumps. The phenomenology of EC effects is first briefly discussed, and EC materials and prototypes are then reviewed. Methods for parameterizing EC effects are summarized and critically analyzed with the goal of guiding experimental design and cautioning against potential …
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Fossil fuel impact of buildings electrification in New York City
… also on a much cleaner grid with the majority of electrical generation being provided by renewable sources, such as solar and wind. In this regard, building electrification is being considered as a possible solution in order to reduce emissions and maximize the efficiency of the energy …
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Dynamic Modeling and Model-Free Real-Time Optimization for Cold Climate Heat Pump Systems
… have been proposed for cold-climate operation of ASHP over the single-stage refrigeration cycle, such as vapor injection techniques and cascade configuration. However, there has been a lack of effective control strategies for such systems to maintain the optimal energy efficiency for operations …
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Investigation of miniature lithium-bromide/water absorption refrigeration systems
… due to the global demand for the reduction of energy usage and the use of harmful refrigerants which are associated with vapour compression refrigeration systems, alternative cooling means, like the Lithium-Bromide/Water (LiBr/H2O) absorption refrigeration system, are being investigated and …
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Numerical analysis of the thermal performance of vapour compression heat pump heat exchanger using Python and computational fluids dynamics (CFD)
… contributes towards the implementation of energy-efficient technologies in the industrial and building sectors. Fin and tube heat exchangers are found in various mechanical applications including heating, ventilation, and air conditioning (HVAC) and refrigeration systems, the oil and gas …
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Numerical modelling of geothermal borehole heat exchanger systems
The large proportion of energy used in the built environment has made improving energy efficiency in buildings, in particular their heating, ventilation, and air conditioning (HVAC) systems, a policy objective for reducing energy consumption and CO2 emissions nationally and internationally. Ground …
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Design, Testing And Controls For Air Source Heat Pump System In Cold Climates Using Natural & Conventional Refrigerants
… greenhouse gas emissions in U.S. Electrification of the buildings has been proved to be the most efficient way to reduce the greenhouse gas emissions where Heat Pumps can be the best alternative to replace the natural gas based heating system to accelerate the electrification process. Among …
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Engineering Mechanocaloric Effects and Tunable Thermal Conductivity in Amorphous Elastic Polymer Fibers
… materials, polymers stand out by several figures of merit, including low cost, chemical inertness, ease of manufacture and scalability, and light weight. They can be engineered by the application of temperature and/or strain, which impose different molecular arrangements within the material, …
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Electrification of domestic heating on the island of Ireland to reduce emissions and enhance system stability
This thesis has investigated if the use of electric heating methods could be used to replace fossil fuel methods in the domestic sector in order to reduce emissions with the added benefit of using them as a demand side management (DSM) source in order to provide grid stability and efficiency, while …
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A THERMO-ECONOMIC STUDY OF SOLAR COOLING/HOT WATER SYSTEMS
… requirements for absorption cooling. The performance could be improved by incorporating a water heating loop in the basic cooling system so that the collectors could be utilised for hot water production during such "idle" periods. Commercial applications for such hybrid systems exist in …
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ENERGY SAVINGS AND THERMAL COMFORT OF SEPARATE SENSIBLE AND LATENT COOLING AIR-CONDITIONING SYSTEMS
… conditioning (AC) systems have limited control of sensible cooling and latent cooling capacities; therefore additional energy-consuming devices, i.e. electric heaters, are often used to reheat the conditioned air in order to provide thermal comfort for the building occupants. Separate sensible …
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The design of a residential water-to-water heat pump
… is becoming more and more important as a means of heating and cooling homes. The American family is booming increasingly aware of year—round air conditioning in all its various aspects, not only for hosting and cooling the homo, but also for humidity control and air filtration. All those tasks …
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