• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.8 no.4
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• pp.24-31
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• 2012

The Solar and geothermal energy have many advantage like low cost, non-toxic, and unlimited. But those the have very low energy efficiency. In this study, the theoretical study of performance in a sola-geothermal hybrid heat pump with operating conditions has carried out. As a result, as the solar radiation increases from 1 $MJ/m^2$ to 20 $MJ/m^2$, the heat pump operating time decreases by 19.5% from 18 times to 14.5 times and the heat pump heat decreases by 23%. Besides, the heating COP increases by 21.4% when the evaporator inlet temperature increases from $11^{\circ}C$ to $19^{\circ}C$. By adapting the geothermal system into a solar hybrid R22 heat pump, the system performance and reliability increases significantly for variable operating conditions during winter season.

• 한국신재생에너지학회:학술대회논문집
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• 2006.11a
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• pp.20-23
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• 2006

Geothermal energy is the natural heat of the Earth. Enormous amounts of thermal energy are continuously generated by the decay of radioactive isotopes of underground rocks and stored in the Earth's interior. Therefore, geothermal energy is one of the most important sustainable energy resources. Recent trends of geothermal energy exploitation technologies focus on the Earth scientific approach to geothermal heat pump system, enhanced geothermal system, aquifer thermal energy storage, underground thermal energy storage, and fluid/heat flow model ing for geothermal wells. Geothermal heat pump distribution in Korea is still in its starting phase in terms of areal utilization sense, we, however, expect to come up with national supply of over 1,000,000 toe by 2020

• 한국태양에너지학회:학술대회논문집
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• 2011.11a
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• pp.328-332
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• 2011

The conclusion is derived from the arranged results and using a simulation by determining the shape of an optimum heat pump which is appropriate for small scale houses. It is concluded as 3 meters long for the laying depth of underground piping of the horizontal type geothermal heat pump system in regard to the 5 RT capacity standard that is suitable for a small scale house. The shape of the horizontal type geothermal heat pump system for a small scale house is theThree pipe shape whose trench length is short and pipe length laid in a trench is short. It is 9 for the number of laying pipes that is most appropriate to system.

• Journal of the Korean Solar Energy Society
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• v.34 no.6
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• pp.103-109
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• 2014

It is important to control the amount of supply water flow rate at all kinds of HVAC systems in order to maintain IAQ and energy efficiency. The most of buildings installed geothermal heat pumps is using fixed water flow rate in spite of the excellent performance of geothermal heat pumps. Especially when the air-conditioning load is low, the flow rate control may be possible to save energy to operate. However, it is effective to apply the variable flow control system in order to reduce energy consumption. Therefore, the purpose of this study, change a water flow rate and improve the whole performance of the geothermal heat pump. Geothermal heat pump system is modeled after the selection of the applied building, by setting the flow rate control to be analyzed through a simulation of performance evaluation. Building energy saving according to the flow rate of the ground circulating water analyze quantitatively and to investigate the importance of the flow control.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.13 no.4
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• pp.31-38
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• 2017

The heating and cooling air conditioning field has been increasing the problems of energy consumption and global warming in the world. A geothermal heat pump has been known as one of the highest efficient heating and cooling system. In this study, the analysis about the test standards of the geothermal heat pump of the Republic of Korea was executed. From the research, the following results were given. It is needed to address the domestic test standard for direct heat exchange geothermal heat pump. Water to air multi geothermal heat pump test standard was only developed in Korea. The test standard to calculate a seasonal energy efficiency ratio for cooling period and heat seasonal performance factor for heating period should be newly developed to estimate actual annual energy consumption and $CO_2$ emission.

• Journal of the Korean Solar Energy Society
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• v.35 no.1
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• pp.45-52
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• 2015

The government is fostering a renewable energy industry as an alternative to handle the energy crisis. Among the renewable energy systems available, geothermal energy is being highlighted as being highly efficient and safely operable without the effect of outdoor air. Accordingly, a study on the geothermal heat pump is in progress in various worldwide perspective. However, Geothermal energy is only in charge of part load of the building due to the high initial installation cost in korea. Moreover, its efficiency is reduced due to the use of independent existing heat sources. In this study, after selecting the building containing the actual installed geothermal heat pump, the use of excellent geothermal heat pump systems was maximized in terms of the energy efficiency. The objective of this study is to show the operation method of geothermal heat pump system to improve energy efficiency through the TRNSYS simulation. This paper proposed operation methods of geothermal heat pump control according to outdoor air temperature. The result of this study is that existing operation method had some problems and if offered improvement is applied to real condition, energy consumption would be decreased.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.638-641
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• 2008

Geothermal water at moderate temperature in a range between 30 to $50^{\circ}C$ exists sparse in surroundings. Mostly they are utilized as heat or water source at spar zones in Korea. However, a large portion of used water is discarded due to its poor recovery quality and inferior application technologies. In this research, an innovative heat pump system based on the hybrid concept that combinate compression cycle and absorption cycle was investigated mathematically. The hybrid heat pump aims to recycle various kind of the heat sources at moderate temperature including geothermal water effectively. The prime objective of the simulation is to design a compression/absorption hybrid heat pump system which can make high temperature above the level of $90^{\circ}C$ and low temperature of $20^{\circ}C$ as well at the same using $50^{\circ}C$ geothermal heat water. As a result, primitive data was provided as a basis to design a prototype 3 RT class hybrid heat pump.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.34 no.11
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• pp.81-87
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• 2018

Among various types of geothermal heat pump systems, Vertical Closed-Loop Geothermal Heat Pump (VGSHP) has received increasing attention due to a variety of advantages such as the potential to be installed in a relatively small space and improved energy efficiency. In this research, the performance of VGSHP system coupled with heat storage tank was evaluated, by analyzing operational behavior of heat storage tank, the variations of heat pump energy performance due to the connection with heat storage tank, part load ratios characteristics of heat pump and the corresponding energy cost, compared to chiller and boiler based conventional system. The results of this study showed that the VGSHP system coupled with heat storage tank showed an energy saving effect of about 18% for cooling and about 73% for heating, and annual heating/cooling energy cost reduction of 43,000,000 KRW ($ 39,000), compared to the conventional air conditioning system. In addition, after considering both energy cost and initial investment cost including equipment, installation and auxiliary device expenses, payback period of approximately 11.8 years was required.

• 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.32 no.1 s.120
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• pp.30-36
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• 2007

Geothermal heat pump systems use the earth as a heat source in heating mode and a heat sink in cooling mode. These systems can be used for heating or cooling systems in farm facilities such as greenhouses for protected horticulture, cattle sheds, mushroom house, etc. A horizontal type means that a geothermal heat exchanger is laid in the trench buried in 1.2 to 1.8 m depth. Because a horizontal type has advantages of low installation, operation and maintenance costs compared to a vertical type, it is easy to be adopted to agriculture. In this study, to heat and cool farm facilities and obtain basic data for practical application of horizontal geothermal heat pump systems in agriculture, a horizontal geothermal heat pump system of 10 RT scale was installed in greenhouse. Heating performance of this system was estimated. The horizontal geothermal heat pump used in this study had heating COP of 4.57 at soil temperature of 14$^{\circ}C$ for depth of 1.75m and heating COP of 3.75 at soil temperature of 7$^{\circ}C$ for the same depth. The stratification of water temperature in heat tank appeared during the whole heat rejection period.