• Journal of Advanced Marine Engineering and Technology
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• v.41 no.1
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• pp.99-104
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• 2017

This study evaluated the heating performance of a hybrid heat pump system. The system was installed in a $100-m^2$ greenhouse to utilize surplus solar energy. A hybrid heat pump system was installed at Jocheon-ri, Jeju Island, for an empirical evaluation of the performance. The system consists of a heat storage tank and plate heat exchangers for several heat exchanges between the greenhouse and heat pump or storage tank. The system uses R410a as the working fluid and is controlled automatically by a defined set temperature of the greenhouse. This system incorporates two kinds of heat sources: outdoor air and a storage tank that collects heat from the topside of the greenhouse. The results showed that the heating capacity was 19.9 kW in the outdoor air source mode and 21.4 kW with direct heating from hot water in the thermal storage tank. These results are very similar to those of a previous study.

• Journal of Energy Engineering
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• v.15 no.3 s.47
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• pp.194-201
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• 2006

Greenhouses should be heated during nights and cold days in order to fit growth conditions in greenhouses. Ground source heat pump (GSHP) systems are recognized to be outstanding heating and cooling systems. A horizontal GSHP system with thermal storage tank was installed in greenhouse and investigated the performance characteristics. The reasons for using thermal storage tank were discussed in detail. Thermal storage tank can provide heat for heating load that is larger than GSHP system heating capacity. The results of study showed that the heating coefficient of performance of the heat pump system was 2.69.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 1999.11a
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• pp.95-99
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• 1999

자연에너지와 전기에너지를 조합하여 냉방과 난방을 수행할 수 있는 방법중의 하나로 히트펌프 이용기술이 있으며, 국내의 경우 히트펌프는 주로 냉방 또는 냉동을 목적으로 이용되고 있으나, 1980년 이후 전기가 풍부한 경제선진국을 중심으로 난방 또는 냉난방겸용의 히트펌프가 개발되어 주택, 빌딩, 온실 등의 공조시스템에 이용되고 있다. (중략)

• Journal of Bio-Environment Control
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• v.22 no.4
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• pp.328-334
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• 2013

A greenhouse heating system to improve heat pump performance using inside and outside air of greenhouse as a heat source selectively and cut $CO_2$ enrichment costs by delay of greenhouse ventilation was developed. In this system, thermal storage modes divided into inside circulation mode using surplus solar energy and outside circulation mode using outside air heat. The thermal storage modes were designed to be switched mutually according to inside greenhouse temperature and six temperature values were input to control the heat pump operating, thermal storage mode switching and greenhouse heating automatically. Operating characteristics of this system were tested in a plastic greenhouse of non-ventilation condition. The results of test showed that the inside circulation mode began at about 11:00 and lasted for about 210 minutes and inside greenhouse temperature was maintained between $20{\sim}28^{\circ}C$ in spite of non-ventilation. System heating COP of the inside circulation mode in the daytime was 3.35, which was 36% and 25% higher than that of the outside circulation modes in the nighttime and daytime respectively.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.39 no.6
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• pp.41-46
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• 2010

시설 재배용 온실에 적용된 냉온수 축열이 결합된 지열 히트펌프시스템에 대하여 설치사례를 소개하였다.

• Journal of Bio-Environment Control
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• v.30 no.4
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• pp.328-334
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• 2021

This study was conducted to analyze the effect of fog cooling during daytime and heatpump cooling at night in greenhouses in summer. During daytime, the average temp. and RH of the control greenhouse which had shading screen were 32.1℃ and 59.4%. and the average temp. and RH of the test greenhouse which had fog cooling were 30.0℃ and 74.3%. At this time, the average outside temp. and RH were 31.4℃ and 57.7%. So, the temp. of the control was 0.7℃ higher than outside temp., but the temp. of the test was 1.4℃ lower than outside and 2.1℃ lower than control. The average RH was 74.3% in the test and 59.4% in control. The average temp. and RH of the control greenhouse which had natural ventilation at night were 25.2℃ and 85.1%, and the average temp. and RH of the test greenhouse which had heat pump cooling were 23.4℃, 82.4%. The average outside temp. and RH at night were 24.4℃ and 88.2%. The temp. of the control was 0.8℃ higher than outside temp., but the temp. of the test was 1.0℃ lower than outside and 1.8℃ lower than control. The average RH was 82.4% in test and 85.1% in control greenhouse. There was no significant difference between the plants growth eight weeks after planting. But after the cooling treatment, the values of stem diameter, plant height, chlorophyll in test were higher than control. The total yield was 81.3kg in test, 73.8kg in control, so yield of test was 10.2% higher than control. As a result of economic analysis, 142,166 won in profits occurred in control greenhouse, but 28,727 won in losses occurred in test greenhouse, indicating that cooling treatment was less economical.

• Korea Journal of Geothermal Energy
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• v.3 no.2
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• pp.19-28
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• 2007

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 1999.11a
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• pp.241-244
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• 1999

시설원예는 노지원예와 달리 인위적인 환경조절을 통하여 주년안정생산이 가능하여야 하고 단위면적당 생산성을 증대시키면서 품질향상을 극대화시키는 것이 생산의 목표이다. 따라서, 주년안정생산을 위하여 고온기에 작물생산이 가능하도록 시설내 고온환경을 조절해야할 것이다. 고온환경을 조절하기 위한 냉방방식에는 자연환기 및 팬을 이용한 온실내부의 공기를 치환하는 방법, 온실내ㆍ외부에 차광망을 설치하여 온실내로 유입되는 일사량의 일부를 차단하는 방법, 수분증발을 통하여 온실내부의 잠열을 빼앗는 증발냉각방식, 히트펌프나 에어컨을 이용한 기계적인 방법이 이용되고 있다. (중략)

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2000.02a
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• pp.178-182
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• 2000

• Journal of Bio-Environment Control
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• v.21 no.4
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• pp.372-378
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• 2012

This study was carried out in order to determine the optimum length of a roll type PE pipe heat exchanger employed in the water-to-water heat pump system using the waste heat of the heated effluent flowed out from thermal power generation plants as a heat source. And the heat pump system of 30 RT for an experimental test was designed and manufactured. And also PE pipes were employed to recover the waste heat from the heated effluent. The inside diameter of PE pipe heat exchanger was 20 mm, the thickness was 2 mm and the diameter of a roll was 1,000 mm. And from the results of this study, we found that the optimum length of PE pipe heat exchanger was 75 m per the heat pump capacity of 1.0 RT (3.51 kW) and then the heating COP of heat pump system was 3.8.