• Proceedings of the SAREK Conference
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• 2008.11a
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• pp.636-641
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• 2008

Heat pump drying has a great potential for energy saving due to its high energy efficiency in comparison to conventional air drying. The heat pump dryer is usually operated at the temperature less than $50^{\circ}C$ and the drying temperature is limited to the operating temperature of the heat pump system. In order to increase the drying temperature, the special box-type heat pump dryer has been developed. The dryer uses the two-cycle heat pump system which has the two heat pump cycles for high and low temperature heating. The high temperature cycle uses the refrigerant 124 to get the temperature greater than $80^{\circ}C$ and the low temperature cycle uses the refrigerant 134a. The drying experiment has been carried out to figure out the performance of the dryer with the selected drying material.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1999.12a
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• pp.211-218
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• 1999

The ambient air is commonly used as low-temperature heat sources for heat pump operation. However, the coefficient of performance (COP) of the air -water heat pump is decreased with the ambient air temperature drop. In this study to solve this problem , the AVACTHE(Automatic Variable Area Capillary Type Heat Exchanger) with 3 levels of heat exchange area(0, 1495.4, 1794.5$\textrm{cm}^2$) was installed in the refrigerant circuit of the heat pump. The AVACTHE effect on the performance of heat pump was tested with the ambient air temperature variation. The high level COP of the heat pump could be achieved by the AVACTHE installation when below -5$^{\circ}C$ of the ambient air temperature.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.15 no.1
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• pp.59-66
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• 2003

The purpose of this study is to analyze the characteristics (COP) of the heat pump system for various operating conditions with the use of seawater heat source and exhaust energy. To accomplish the goal, first of all, the computer simulation for heat pump system is carried out. The heat pump system model is made of a waste heat recovery system and a vapor compression refrigeration system, and the working fluid is R-22. The model calculated the change of COP with the variation of temperature and flow rate. The COP and the plate heat exchanger (PHE) area of the heat pump system are considered moderately high in the condensation temperature of $25^{\circ}^C$ and the evaporation temperature of $2^{\circ}^C$ in indoor culture system. The simulation results will be used effectively for the design and the performance prediction of heat pump system using unused energy in a land base aquaculture system.

• 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 Biosystems Engineering
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• v.25 no.4
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• pp.273-278
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• 2000

The hybrid heat pump system of the air to air and / or air to water was composed and its COP was analyzed with the ambient temperature on the opened and closed loop system respectively. The results be indicated by the equation(7) that the COP(Coefficient of Performance) of air-source(air to air and / or air-water) heat pump is effected with the ambient air temperature and AVACTHE.(Automatic Variable Area Capillary Type Heat Exchanger) 2. The COP of air-to-water heat pump without AVACTHE decreased in accordance with the ambient temperature decrease, however in case of the heat pump with AVACTHE the COP was maintained at 2.8∼3.0 level when the ambient temperature decrease from -$5^{\circ}C$ to $-11^{\circ}C$. 3. The COP of the air-to-water heat pump operated on the open loop was higher 40∼58% than that of the heat pump operated on the close loop. 4. The lower ambient temperature air effect on the COP of the air-to-air heat pump operated on the semi closed loop could be controlled using the AVACTHE, and at the high ambient air temperature the COP increased using the Bypass circuit.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.22 no.12
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• pp.821-827
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• 2010

Study on the performance characteristics of the solar hybrid system with heat pump operating temperature during winter season has performed by using an experimental test. The system performance and operating characteristics with the heat pump operating temperature, hour and load condition were investigated and analyzed. As a result, the hot water temperature was significantly affected by the heat pump operating temperature at the morning(time 1) and noon(time 2). However, hot water temperature was set by the radiation quality and collecting operation hour at the afternoon(time 3). In addition to the solar fraction was decreased for the high heat pump operating temperature because the heat pump operated with a long operating time and short operating period.

• Journal of Biosystems Engineering
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• v.24 no.4
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• pp.343-350
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• 1999

The ambient air is commonly used as low-temperature heat source for heat pump operation. However, the coefficient of performance(COP) of the air to water heat pump is decreased with the ambient air temperature drop. In this study to solve this problem, the AVACTHE(Automatic Variable Area Capillary Type Heat Exchanger) with 3 levels of heat exchange area(0, 1,495.4, 1,794.5$\textrm{cm}^2$)was installed in the refrigerant circuit of the heat pump. The AVACTHE effect on the performance of heat pump was tested with the ambient air temperature variation. The COP improvement of the heat pump could be achieved by the AVACTHE installation when below -5$^{\circ}C$ of the ambient air temperature.

• Journal of the Semiconductor & Display Technology
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• v.19 no.2
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• pp.110-114
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• 2020

In this paper, a heat pump using a Peltier device was developed for heat dissipation in a sealed electric box. The heat pump was designed with a cooling fin attached to both sides of the Peltier device, and a fan was mounted on the cooling fin on the hot side to increase the efficiency. The heat dissipation efficiency could be improved by directly connecting the electronic component having high heat to the cooling fin using a heat conducting wire. The fabricated heat pump was designed to operate only in the temperature range set by the temperature control system to improve the problem of high power consumption of the Peltier element.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.12 no.1
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• pp.17-22
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• 2016

It is very important to obtain a out-of season production in horticultural greenhouses corresponding with higher crop prices. A ground source heat pump system has been highly spotlighed as an energy efficient heating system for the greenhouse. This paper investigated the operating cost of the ground source heat pump system with the variation of generating temperature and designing methods for heating system of the greenhouse. Even though the COP of the ground source heat pump system decreased with an increment of generating temperature in heating mode, the operating cost could be reduced. By adopting the high temperature heat pump system and heat storage tank, it could be achieved to save energy and reduce the operating time of auxiliary oil heating system for producing good plant-growth in the greenhouse.

• Journal of Fisheries and Marine Sciences Education
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• v.18 no.3
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• pp.229-235
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• 2006

This study investigated physiology and psychological response of subjects, when heat pump was operated long time within comfort temperature range. Eight subjects were participated for the experiment. Their age was from 22 to 25 years old. The results of this experiment will propose basic data for improving comfort control algorithm in fluctuating environment by using heat pump. When indoor temperature was controlled by heat pump, the conclusion was as follows. 1) When votes of subjects was considered, the thermal comfort neutrality or lower range helped formation of comfort sensation for subjects. 2) When room temperature was lower, thermal comforts of shoulder, knee and foot with subjects thermal comfort showed high correlation. And when room temperature was higher, thermal comfort of face region with subjects thermal comfort showed high correlation. 3) The necessity of temperature change after 50 minutes from initially operating heat pump demands the additional analysis against the physiological signal.