• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.561-566
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• 2009

Alluvium is sedimentary stratum and composed of gravel, sand, silt, clay. Permeability of alluvium is the higher. If alluvium have lots of aquifer, will be of great use heat source and heat sink of heat pump. Alluvium aquifer contain the thermal energy of surrounding ground. Also geothermal heat pump using alluvium aquifer reduce expenses than general geothermal heat pump, because geothermal heat pump using alluvium aquifer make use of single well. In this study geothermal heat pump using alluvium aquifer was installed and tested for a building. The heat pump capacity is 30USRT. Temperature of ground water is in $12{\sim}17^{\circ}C$ annually and the quality of the water is as good as living water. The heat pump cooling COP is 4.4 ~ 4.7. The system cooling COP is 3.25 ~ 3.6. This performance is as good as BHE type ground source heat pump.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.3 no.4
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• pp.263-275
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• 1991

Studies on the annual performance of three different type of solar-absorption heat pump system (parallel type, series type, and generator type) are carried out by using the computer simulation. These include the calculation of solar energy from the solar collector, and the revision of computer package, developed by Oak Ridge National Laboratory, to predict the annual performance. Finally using weather data and load conditions, the annual performance are obtained. Results show that the annual operating costs of three solar-absorption heat pump systems are almost same values and 44% lower than that of the pure absorption heat pump system. The total annual input energys of solar-absorption heat pump systems are also about 44% lower than that of the pure absorption heat pump. The nominal size of the solar-absorption heat pump systems can be reduced to a value of 55% that of the pure absorption heat pump that would normally be specified under identical conditions.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.15 no.12
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• pp.979-986
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• 2003

The performance characteristics of heating and cooling operation for a heat pump system using seawater heat source and exhaust energy are presented. The heat pump system is made of a waste heat recovery system and a vapor compression refrigeration system. The working fluid is R-22. The heat pump system COPs are measured during heating and cooling operation modes, and the resultant COPs were 9.7 and 7.9, respectively, which are three times higher than those of the heat pump itself. Therefore, the performance of the heat pump system using exhaust energy is excellent compared to that of a general heat pump. The experimental data can be effectively used for the design of the high efficient heat pump using a seawater heat source.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.16 no.3
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• pp.8-16
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• 2020

This paper presents the heating performance analysis results of a ground-source heat pump (GSHP) system using hybrid ground heat exchanger (HGHE). In this paper, the HGHE refers to the ground heat exchanger (GHE) using both a surface water heat exchanger (SWHE) and a vertical GHE. In order to evaluate the system performance, we installed monitoring sensors for measuring temperatures and power consumption, and then measured operation data with 4 different load burdened ratios of the HGHE. During the entire measurement period, the average heating capacity of the heat pump was 37.3 kW. In addition, the compressor of the heat pump consumed 9.4 kW of power, while the circulating pump of the HGHE used 6.7 kW of power. Therefore, the average heating coefficient of performance (COP) for the heat pump unit was 4.0, while the system including the circulating pump was 2.7. Finally, the parallel use of SWHE and VGHE was beneficial to the system performance; however, further researches are needed to optimize the design data for various load ratios of the HGHE.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.1964-1968
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• 2007

The river water heat source heat pump has the advantage in the performance compared to air source heat pump. Although its better performance, the large temperature difference between load and source makes system performance worse by nature. In this study, 2-stage compression is considered as the solution of this problem. Generally, heat pump is designed for maximum capacity rate, but it actually operates at part load condition in many cases. Therefore, an information on the part-load character is very important in view of the system overall performance. In this study, part-load performance tests of a R134a 2-stage compression heat pump were carried out over the river water and supply heating water temperature changes. The experimental results show that the system performance is influenced by the part load rates, river water temperature, load temperature, etc.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.5 no.1
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• pp.13-17
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• 2009

The river water heat source heat pump has the advantage in the performance compared to air source heat pump. In this study, an experimental study on a 2-stage heat pump, which is designed to utilize a river water heat source, were carried out. Generally, a heat pump is designed for maximum capacity rate, but it actually operates at part load condition in most cases. Therefore, an information on the part-load characteristic is very important in view of the system overall performance. In this study, part-load performance tests of a R134a 2-stage compression heat pump were carried out over the river water and supply heating water temperature changes.

• Journal of Biosystems Engineering
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• v.24 no.6
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• pp.501-512
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• 1999

In this study, the coefficient of performance of a vapour compression heat pump system was analyzed for the evaluation of the heat pump performance. A water-to-air heat pump was assembled and tested by changing the level of the compressor driving speed and the air mass flow rate during air heating process. The coefficient of performance for air heating was 2.6~3.8 and that for water cooling was 1.0~1.4. The coefficient of performance was not depending on the levels of the compressor driving speed or levels of the air mass flow rate, but on the temperature of the air and water. The coefficient of performance for air heating increased by about 0.2 with the water temperature increasing by 1$^{\circ}C$.

• 한국태양에너지학회:학술대회논문집
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• 2012.03a
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• pp.534-542
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• 2012

Vertical closed-loop ground source heat pump systems(GSHP) have been installed widely in Korea since it can extract moderate temperature level of geothermal heat in a small area. As a ground heat exchanger, a vertical closed-loop type with brine circulation is mostly preferred since it is simple and less harmful to ground environment. However, it requires a secondary heat exchange loop between the refrigerant in a heat pump and the brine. By adding a geothermal heat exchanger in the secondary heat exchange loop, circulation pumps should be attached and the temperature difference between refrigerant and ground is increased, which are important parts of performance degradation. In this paper, annual and seasonal performances of direct expansion(DX) geothermal heat pump were estimated mathematically as an alternative of classical indirect geothermal heat pump based on the annual performance evaluation. As a result, DX geothermal heat pump showed 43% higher annual performance than the classical U-tube geothermal heat pump.

• Journal of the Korean Solar Energy Society
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• v.32 no.3
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• pp.114-122
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• 2012

Vertical closed-loop ground source heat pump systems(GSHP) have been installed widely in Korea since it can extract moderate temperature level of geothermal heat in a small area. As a ground heat exchanger, a vertical closed -loop type with brine circulation is mostly preferred since it is simple and less harmful to ground environment. However, it requires a secondary heat exchange loop between the refrigerant in a heat pump and the brine. By adding a geothermal heat exchanger in the secondary heat exchange loop, circulation pumps should be attached and the temperature difference between refrigerant and ground is increased, which are important parts of performance degradation. In this paper, annual and seasonal performances of direct expansion(DX) geothermal heat pump were estimated mathematically as an alternative of classical indirect geothermal heat pump based on the annual performance evaluation. As results, DX geothermal heat pump showed 43% higher annual performance than the classical U-tube geothermal heat pump.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.26 no.6
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• pp.257-262
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• 2014

This paper describes an experimental study for heating performance that can be used in R-134a automobile heat pump systems. The heat pump system is widely studied for heating system in zero-emission vehicles to attain both the small power consumption and the effective heating of the cabin. This paper presents the experimental results of the influence on heating capacity and coefficient of performance of heat pump system. Tests were performed with different sizes of internal and external heat exchangers, and refrigerant flow rate was also considered in two-way flow devices. In addition, the heat, air, and water sources with the heat pump system were examined. The experimental results with the heat pump system were used to analyze the impact on performances. The best combination of performance was A-inside heat exchanger, B-outside heat exchanger, and B-flow device, respectively. In addition, a water heat-source was found to give roughly 40% of better performance than an air heat-source heat pump system.