• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.14 no.6
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• pp.512-518
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• 2002

The real chip and similarity model were used to investigate the thermal behavior and velocity distribution of air from the heat source with the location and the amount of heat experimentally and numerically, and compared. The heat generated in the block is not cooled by convection and show the high temperature by the stagnation of heat flow. After maintaining the high temperature of block by the natural convection, the sudden drop of temperature with the air flow was shown in the channel but the decreasing rate was small with the time. The inward block was effected by infinitesimal air flow generated between block and channel and outward block was effected by the entry condition.

• 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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• 2008.06a
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• pp.357-362
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• 2008

The present study has been conducted variable refrigerant flow system applied building. Multi air-conditioning system has some benefits : easier building management and maintenance and energy saving. Recently, the system heat pump has been employed in medium-sized and tall buildings. However, the performance data and design method for system heat pump are limited in literature due to complicated system parameters and operating conditions. In the present study, case study of a system heat pump applied various building. The aim of this paper is to application multi air-conditioners and to inform the benefits of multi air-conditioners.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.55 no.1
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• pp.35-40
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• 2006

Heat-pump system has a special feature that provides heating operation in winter season and cooling operation in summer season with a single system. It also has a merit that absorbs and makes use of wastewater heat, terrestrial heat, and heat energy from the air. Because heat-pump system uses midnight electric power, it decreases power peak load and is very economical as a result. By using the property that energy source is converted to low temperature when losing the heat, high temperature energy source is used to provide heating water and low temperature energy source is used to provide cooling water simultaneously in summer season. This study made up a heat-pump system with 4 air heat sources and a water heat source and implemented the optimal operation algorithm that works with numbers of heat pumps to operate them efficiently. With the heat-pump system, we applied it to cooling and heating operation in summer season operation mode in a real building.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.634-637
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• 2008

Ground source heat pumps are clean, energy-efficient and environment-friendly systems cooling and heating. Although the initial cost of ground source heat pump system is higher than that of air source heat pump, it is now widely accepted as an economical system since the installation cost can be returned within an short period of time due to its high efficiency. In the present study, performances of ground source compound hybrid heat pump system applied to a large community building are simulated. The system design and operation process appropriate for the surrounding circumstance guarantee the high benefit of the heat pump system applied to a large community building. If among several renewable energy sources, ground, river, sea, waste water source are chosen as available alternative energies are combined, COP of the system can be increased largely and hybrid heat pump system can reduced the fuel cost.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.10 no.6
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• pp.695-701
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• 1998

Researches on unused energy are being continued because of the limited fossil fuel and the destruction of environment. Therefore this study was peformed as follows. The collectable amount of exhausted heat for an air-conditioning was calculated by the subway thermal environment prediction program. And the electric power needed by conventional heat source equipments was compared with one by unused heat source equipments when the exhausted heat was used by heat pump in heating and hot water supplying. The results are summarized as follows; 1) Forced ventilation should be conducted to keep optimal temperature in subway tunnel in summer as well as in winter. According to the simulation, temperature in tunnel was higher than that on the ground in summer when the forced ventilation was conducted only in winter. 2) Ventilating time should be calculated out to the optimal condition for not only saving power of ventilation fan but reusing exhausted heat. By the simulation, it is certain that the exhausted heat should be eliminated in air-conditioning time. 3) The use of exhausted heat source heat pump could save 8% of electric power per hour in comparison with existing heat pump. It was based on a present heat generation and traffic for ventilating time of general air-conditioning, but could be different by ventilating time. 4) As the traffic increases up to 1.5 or 2 times, electric power consumption of the conventional heat pump increases to 11% or 13.5% per mean hour in comparison with that of the exhausted heat source heat pump, though all-day ventilation.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.8 no.4
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• pp.17-23
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• 2012

Due to reinforcement of international environment regulation and high oil prices, interest in renewable energy is growing. Countries participating in UNFCCC are continuously putting efforts in reducing greenhouse gas after enforcing Kyoto Protocol into effect on Feb, 2005. Energy used in buildings, which relies heavily on fossil fuel accounts for about 24% of total energy consumption. In this study, air, geothermal and water source heat pump systems for an 322 $m^2$ auditorium in an office building is simulated using TRNSYS version 17 for comparing energy consumptions. The results show that energy consumptions of air, geothermal and water source heat pumps are 14,485, 10,249, and 10,405 kWh, respectively. Annual equal payments which consider both initial and running costs become 5,734,521, 6,403,257 and 5,596,058 Won. Thus, water source heat pump is the best economical choice.

• Solar Energy
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• v.18 no.4
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• pp.11-22
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• 1998

Floor panel heating system using hot water is the primary heating system of domestic residential building. This paper presents the results of performance analysis of the heat pump system with air source evaporator and single unit dual sink(SUDSk) condenser. The heat exchanger combines two separated condensers into a single condenser and the object of the SUDSk condenser is to release energy to dual sinks, i.e. air for air heating system and water for panel heating system in one single unit. Simulation program is developed for single unit dual source(SUDS) SUDSk heat pump system and some experimental data are obtained and compared with simulation results. Differences of heating capacity and COP in dual source operating mode are 7% and 8% respectively. Simulation results are in good agreement with test results. Therefore, developed program is effectively used for design and performance prediction of dual source dual sink heat pump system with SUDS evaporator and SUDSk condenser.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.25 no.11
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• pp.600-605
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• 2013

Ground source heat pump systems (GSHP) can achieve higher performance of the system, by supplying more efficient heat source to the heat pump, than the conventional air-source heat pump system. But building clients and designers have hesitated to use GSHP systems, due to expensive initial cost, and uncertain economic feasibility. In order to reduce the initial cost, many researches have focused on the energy-pile system, using the structure of the building as a heat exchanger. Even though several experimental studies for the energy-pile system have been conducted, there was not enough data of quantitative evaluation with economic analysis and comprehensive analysis for the energy-pile. In this study, a prediction method has been developed for the energy pile system with barrette pile, using the ground heat transfer model and ground heat exchanger model. Moreover, a feasibility study for the energy pile system with barrette pile was conducted, by performance analysis and LCC assessment. As a result, it was found that the heat exchange rate of a barrette pile was 2.55 kW, and the payback period using LCC analysis was 8.8 years.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.23 no.6
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• pp.400-405
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• 2011

This paper presents the heating performance characteristics of the air source heat pump with air to water type. The heating capacity, COP, P-h diagram were measured at various operating conditions, air-side temperatures, relative humidities, and inlet/outlet water temperature under the standard heating condition of KS B 6275. The experimental data for the heat pump were measured using the air-enthalpy calorimeter and the constant temperature water bath. As the air-side temperature increases, the heating capacity and COP increase. The effect of the air-side relative humidities on the heat pump performance is insignificant. The heat pump performance on inlet and outlet water temperatures and air-side temperatures(-7, -11, $-15^{\circ}C$) were studied. Heating capacity and COP increased about 27~39% with the air-side temperature increasing. Enthalpy between the front and the rear of condenser decreased about 6% by increasing of the inlet water temperature. These results can be utilized in the design of the air source heat pump system with air to water type.