A Study on the Performance of a Cascade Heat Pump for Generating Hot Water

Boahen, Samuel; Choi, Jong Min

doi:10.3390/en12224313

Cited by 5 publications

(2 citation statements)

References 17 publications

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“…This improvement should increase the COP value of the system. The performance of the cascade system is still a subject of research [32,[55][56][57]. In small heat pumps, such a system is not common, due to the higher initial cost.…”

Section: • Cascade Variantmentioning

confidence: 99%

Efficiency of a Compressor Heat Pump System in Different Cycle Designs: A Simulation Study for Low-Enthalpy Geothermal Resources

et al. 2022

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The development of district heating systems results in a search for alternative heat sources. One of these is low-enthalpy geothermic energy, more available than traditional geothermal energy. However, utilization of these resources is difficult, due to the low quality of the produced heat. To utilize them, the heat pump system can be used. Such a system was designed for this case study of a city in a region of the Polish Lowlands. The data necessary for the design came from the project of the borehole and operational parameters of the existing heating plant. Four heat pump-cycle designs were proposed, modeled, and simulated using Ebsilon software. Afterward, the designs were optimized to achieve maximum coefficient of performance (COP) value. As a result of the simulation, the efficiency of each design was determined and the seasonal COP value was calculated with the annual measured heat demand of the plant. The system based on the cascade design proved the most efficient, with a seasonal COP of 7.19. The seasonal COP for the remaining basic, subcooling, and regenerator variants was 5.61, 3.73, and 5.60, respectively. The annual heat production of the designed system (22,196 MWh) was calculated based on the thermal power of the designed system and historical demand data. This paper presents a simulation methodology for assessment of the efficiency and feasibility of a heat pump system in district heating.

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Section: • Cascade Variantmentioning

confidence: 99%

Efficiency of a Compressor Heat Pump System in Different Cycle Designs: A Simulation Study for Low-Enthalpy Geothermal Resources

et al. 2022

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“…air, water). While, on the other hand, they are producing sustainable energy since the same input power for heat pump generates much more useful energy compared to a traditional heating system [7]. Even though energy produced by heat pumps is renewable and thus environmentally friendly, it is also crucial to select appropriate working fluids.…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic Optimization of Cascade Heat Pump

Kovačević¹,

Rudonja²,

Gojak³

2020

Proceedings of the 51st International HVAC&R Congress and Exhibition

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In today’s modern world, development of industry and technology has led to the increase in energy demand. Hence, more fossil fuels are burnt in order to cover this demand. Due to the multiple disadvantages, as well as the negative impact that burning of fossil fuels has on the environment, heat pumps are gaining more importance when providing energy for heating. This paper is aimed at conducting thermodynamic optimization of cascade heat pump in terms of different working fluid combinations and calculating maximum COP. In order to perform thermodynamic analysis, a software program that uses database of working fluids, was developed. The intermediate temperature within cascade heat exchanger represents a crucial parameter when analyzing and designing cascade heat pumps. Thus, when performing thermodynamic analysis, the intermediate temperature was varied in the range from 0°С to 25°С and the optimal temperature that provides maximum COP was defined. The analysis was performed on an air–to–water heat pump, that could be used for heating different types of buildings in places in Serbia where the outdoor design temperature is –20°С. The cascade heat pump would be used alongside radiator heating system operating at temperatures 70°С/50°С. Due to the high temperature difference between heat source and heat sink, cascade heat pumps have advantages over single stage or multi stage heat pumps. The optimization was performed on an air–to–water cascade heat pump where the evaporation and condensation temperatures were –25°С and 75°С, respectively. Following the conducted optimization, the analysis of the impact that isentropic efficiency of compressor has on COP was examined.

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