• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.15 no.2
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• pp.10-16
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• 2019

In this study, the present regulation of heat metering for the ground source heat pump was investigated. The ground source heat pump has been adopting the heat metering system used in the district heating system for estimating the heating and cooling energy production amount. The accuracy of the present heat metering systems for a water to water ground source heat pump is low, because the system for district heating has a relatively high temperature range comparing with the ground source heat pump operating conditions. Even though the heat amount for the building side should be measured, the heat absorption and extraction amount from or to the ground was measured for the water to air ground source heat pump due to the difficulty of estimating the air side heating and cooling capacity in the present regulation. It is highly recommended to validate the heat metering system to have reliability for the ground source heat pump and develop the system to be applicable water to air ground source heat pump.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.17 no.4
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• pp.68-78
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• 2021

In order to solve the increasing deterioration of the energy shortage problem, ground-source heat pump (GSHP) systems have been widely installed. The control method is a significant component for maintaining the long-term performance and for reducing operation cost of GSHP systems. This paper presents the measurement and analysis results of the cooling performance of a GSHP system using capacity control with outdoor air temperature. For this, we installed monitoring equipments including sensors for measuring temperature, flow rate and power consumption, and then monitored operation parameters from July 9, 2021 to October 2, 2021. From measurement results, we analyze the effect of capacity control with outdoor air temperature on the cooling performance of the system. The average performace factor (PF) of the heat pump was 6.95, while the whole system was 5.54 over the measurement period. Because there was no performance data of the existing GSHP system, it was not possible to directly compare the existing control method and the outdoor air temperature method. However, it is expected that the performance of the entire system will be improved by adjusting the temperature of cold water produced by the heat pump, that is, the temperature of cold water on the load side according to the outside air temperature.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.12 no.3
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• pp.244-250
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• 2000

An air source heat pump using liquid injection technique, which can be applied for very low temperature climate, has been simulated to examine the design options. Comparison between the simulation and experiment has been carried out to validate the simulation method. Effects of various design parameters such as liquid injection rate and injection pressure are Investigated to optimize the performance of the heat pump. Finally, optimal liquid infection rate and injection pressure to maintain sufficient heating capacity and moderate discharge refrigerant temperature are suggested when the heat pump was operated at very low outdoor temperature.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.17 no.11
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• pp.1005-1013
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• 2005

The use of river water as a heat source of a heat pump has the advantage in the performance compared to the use of atmospheric air because the temperature variation of river water over the year is relatively small. In this study, the performance of the heat pump system using river water as a heat source was numerically investigated. A simulation model for the 2-stage compression heat pump system was developed with each component model composed of compressors, heat exchangers, a flash tank and electronic expansion devices. The peformance of the heat pump system using river water was improved by $50\%$ compared to that using atmospheric air in winter conditions.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.200.1-200.1
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• 2011

Underground air is a special energy source in Jeju and distributes lava cave, pyroclastic, open joint, and crushing zone. A possible area to utilize underground air is 85% of Jeju except to the nearby area of Sambang Mt. and 25m high coastal area from sea level. In Jeju, underground air is used for heating agricultural facilities such as greenhouse cultivated mangos, Hallbong and mandarin orange, pigsty, mushroom cultivation house, etc. and fertilizing natural $CO_2$ gas by suppling directly into agricultural facilities. But this heating method causes several problem because the underground air has over 90% relative humidity and is inadequate in heating for crops. Mangos are the most widely grown tropical fruit trees and have been cultivated since 1993 in Jeju. In Jeju, the cultivating area is about 20ha and amount of harvest is 275ton/year in 2010. In this study, the heat pump system using underground air as heat source was installed in mangos greenhouse which area is $495m^2$. The capacity of heat pump system and heat storage tank was 10RT, 5ton respectively and heating effect and heating performance of the system were analysed.

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.1373-1378
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• 2009

This study is aiming comparison and analization between efficiency of hybride air conditioning system which uses low temperature water under dam and air and EHP(Electric Heat Pump). The experimental was carried out with air cooling tests for EHP system having 80HP and composition heat pump system. P-i diagram of both systems and COP was used to derive schemetic and calcuations. As results of the tests, hybride system has 1.4 time higher efficiency coefficient.

• Transactions of the Korean hydrogen and new energy society
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• v.2 no.1
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• pp.39-46
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• 1990

In order to improve the power of hydride heat pump, prototype heat pump was constructed using $Zr_{0.95}Ti_{0.05}Cr_{0.9}Fe_{1.1}$-$Zr_{0.9}Ti_{0.1}Cr_{0.6}Fe_{1.4}$ which had very good hydrogenation properties. The power changed with operating parameter such as cycle time, air flow rate, and temperature of hot air was investigated. The power shows maximum value with cycle time. The power increased with air flow rate and temperature of hot air. The power of the heat pump was $65-72 Kcal/Kg-alloy{\cdot}h$ under optimum operating condition, which was superior to that the system using $LaNi_{0.9}Al_{0.3}-MmNi_{4.15}Al_{0.66}Fe_{0.2}$ alloy pairs.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.12 no.2
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• pp.1-6
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• 2016

A ground air heat exchanger (GAHX), also called earth air heat exchanger is a useful technology to be integrated with other renewable energy technologies. In this study, ground-air heat exchanger system for the air source heat pump is introduced. The purpose of this study is to design the volumetric flow rate and the length of GAHX system. A GAHX length model equation has been developed and used for calculation. GAHX thermal efficiency are recommended as 75% and 85% in order to optimize pipe length. $2,750m^3/h$, $2,420m^3/h$ of volumetric flow rate on 88.3m, 111.7m length are suggested for providing 7.5kW thermal capacity. And the number of path is recommended more than two to minimize pressure drop. For future study, advanced model equation study with ground thermal behavior and a more efficient GAHX design will be considered.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.26 no.11
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• pp.529-534
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• 2014

This research developed a hybrid heat pump system with the functions of dehumidification and heating, which uses simulated air that is like underground air, from an environmental chamber as a heat source. The system consisted of three evaporators and three condensers that were installed in series in the air passage, between the underground and load space. As results, the total amount of dehumidification was 2.726 kg/h, and the heating $COP_h$ was 1.84 at air intake temperature $17^{\circ}C$ and relative humidity 70%, which is a similar condition to underground air. We found that the total amount of dehumidification also increased with the air temperature and humidity. The system $COP_s$ was reached at 2.5, if we include the latent heat of dehumidification in the conventional heat pump system's COP.

• Magazine of the Korean Society of Agricultural Engineers
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• v.43 no.6
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• pp.120-126
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• 2001

This experiment was carried out to analyse on the cooling and dehumidifying effects of greenhouse by air-to-water heat pump system employing the air as cooling source. following results were obtained ; 1. The coefficients of performance (COP) of heat pump itself and total heat pump system were approximately 2.71~2.88 and 1.99~2.22, respectively. 2. The night-time cooling load of experimental greenhouse was 64.9 MJ/h, and the heat absorbed (cooling load) from heat pump system was 816.3~1,004.6 MJ/day. 3. The dehumidified moisture amount from experimental greenhouse was 7.0~15.0 kg/h. 4. The night time temperature of experimental greenhouse cooled by heat pump system could be maintained 4~6$^{\circ}C$ lower than that of control greenhouse which was almost equal to outside air temperature.