• Title/Summary/Keyword: 성적계수

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Analysis of Performance Characteristics of a Cascade Refrigeration System with Internal Heat Exchanger using Natural Refrigerants (천연냉매를 사용하는 내부 열교환기 부착 캐스케이드 냉동시스템의 성능 특성 분석)

  • Son, Chang-Hyo;Oh, Hoo-Kyu
    • Journal of Advanced Marine Engineering and Technology
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    • v.33 no.8
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    • pp.1123-1128
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    • 2009
  • In this paper, the cycle performance characteristics of a cascade refrigeration system with internal heat exchanger using natural refrigerants is presented to offer the basic design data for the operating parameters of the system. This system considered in this study is consisted of a high temperature cycle using a carbon dioxide(R744) and low temperature cycle using refrigerants such as R290, R1270, R600a and Ethane. The main results were summarized as follows : The COP of the cascade refrigeration system of R600a with internal heat exchanger is the highest grade in low temperature cycle using refrigerants such as R290, R1270, R600a and Ethane. The COP of the cascade refrigeration system with internal heat exchanger only in high temperature cycle is the highest value among three type cycle, such as only low temperature cycle, only high temperature cycle and all the cycle.

Demonstration project on utilization of solar thermal energy on Hybrid Cooling and Heating system (태양열 이용 Hybrid냉난방시스템 실증연구)

  • Mun, Jong-Chul
    • 한국신재생에너지학회:학술대회논문집
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    • pp.363-372
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    • 2005
  • 최근 고유가상황 및 에너지소비가 증대되는 사회적 분위기와 환경적 변화에 힘입어 대체에너지기술개발에 대한 절실한 대책마련이 중요시 되고있다. 기후변화협약의 발효로 환경에너지에 대한 새로운 인식의 필요로 에너지체제의 변환이 촉구되어지고 있으며 이에 따른 환경친화적 에너지자원을 이용한 신 재생에너지개발에 대한 연구개발기술이 관심을 받고 있다. 현재 사용중인 화석연료는 환경오염 및 지구의 온난화 현상 등 심각한 공해문제를 야기시키고 있는 반면에 태양에너지와 같은 청정에너지의 개발은 환경오염방지와 친환경에너지자원의 활용이라는 점에서 관심이 대상이 되고 있고 특히, 우리나라의 경우 에너지수입 의존율이 97%로 높은 상황에서 국가에너지대책을 수립하고 해외수입에너지 의존율을 최소화시키기 위하여 가히 필수적인 상황이다. 따라서, 본 실증연구사업(태양열 이용 Hybrid냉난방시스템 실증연구)은 태양열 집열기에서 생산된 저온의 $20\sim30^{\circ}C$의 승온된 양질의 열원을 히트펌프 증발기 열원으로 이용 히트펌프의 압축동력이 상대적으로 작아져 기존 히트펌프 시스템에서의 성적계수(COP)를 높여 주는 효과를 기대할 수 있고, 특히 하절기 복사량이 많은 시기에는 $50\sim60^{\circ}C$ 정도로 승온되어진 중 고온수를 직접 온수탱크로 이동시켜 필요수요처에 공급함으로써 이에 따른 에너지절감효과를 기대할 수 있다. 구축된 태양열 이용 하이브리드(Hybrid)냉난방시스템은 계절별, 설비별 특성을 적절히 활용하여 연평균 집열기 효율은 70%수준으로 유지하면서, 계절별 성적계수는 '4'수준을 목표로 하여 추진되었으며, 그간, 태양열 이용 보급분야의 실용화는 주로 건물의 급탕용 온수생산의 수준에 머물렀으나 이 단계를 극복한 건물의 냉 난방 및 급탕을 위한 태양열 및 공기열원을 활용한 하이브리드(Hybrid)냉난방 시스템 구축하였다. 아울러, 태양열 이용 하이브리드 냉난방 히트펌프 시스템 실증 실험은 유가상승과 신재생에너지에 대한 국가적 분위기 고취로 어느때 보다도 개발기술의 상용화 및 실용화적 측면의 염두와 태양열 이용 Hybrid냉난방 시스템의 효율향상과 저가화를 통해 기술의 경제성과 신뢰성을 확보하여 태양열 이용 시스템의 보급활성화를 목표로 하고 있다.

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An Experimental Study on Application of Hydrocarbon Refrigerants for Heat Pump (히트펌프에서 탄화수소냉매 적용에 관한 실험적 연구)

  • Yoo, Seong-Yeon;Park, Dong-Seong;Kang, Tae-Seok;Lee, Je-Myo
    • Proceedings of the KSME Conference
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    • pp.1264-1269
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    • 2004
  • This research describes the application of hydrocarbon refrigerants for heat pump system which is needed for fish farm. Tested refrigerants are HCFC-22 and hydrocarbon refrigerants(CARE 50 and ASR-20). CARE 50 is mixture of R-290 and R-170, and ASR-20 is mixture of R-152a, R-290 and other additives. Heat pump consist of shell and tube heat exchanger, scroll compressor, expansion valve and accumulator. Manual expansion valve is used for testing of wide range evaporating temperature. Hydrocarbon refrigerants show a good performance as an alternative for HCFC-22 in the range of evaporating temperature from $-6^{\circ}C$ to $6^{\circ}C$.

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An experimental study on cooling characteristic of a thermoelectric module (열전모듈의 냉각특성에 관한 실험적 연구)

  • Hwang, Jun;Kang, Byung Ha
    • Transactions of the Korean hydrogen and new energy society
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    • v.15 no.4
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    • pp.341-347
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    • 2004
  • An experimental study has been carried out on cooling perfonnance of a thennoelectric module. This problem is of particular interest in the design of the refrigeration systems using thermoelectric module, such as cosmetic refrigerator, wine cellar and air cooler. The effect of the input voltage and the hot side temperature on the cooling performance is studied in detail. The $\Delta$T, temperature difference between cold side and hot side surface of thermoelectric module, is described in terms of the input voltage and the hot side temperature. It is found that the cooling capacity can be improved by increasing the input voltage and by reducing the heat from the hot side of the thermoelectric module. However, COP is decreased with an increase in the input voltage, since power consumption is also increased. Thus, optimum input voltage can be selected based on cooling capacity and COP.

Experimental Study for Horizontal Geothermal Heat Pump Heating Performance Analysis (수평형 지열 히트펌프 난방 성능 분석을 위한 실험적 연구)

  • Ihm, Pyeong chan;Cho, Sung woo
    • Journal of the Korean Society for Geothermal and Hydrothermal Energy
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    • v.12 no.2
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    • pp.7-12
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    • 2016
  • This study have an objective to suggest basic data and measured result of heating performance on water-water type horizontal geothermal heat pump which is based on heating and cooling load calculation result of small residential house. The average temperature during measured periods is $9.4^{\circ}C$ on primary EWT and is $7.6^{\circ}C$ on primary LWT. The temperature difference shows $1.8^{\circ}C$ as average temperature. Because the average outdoor temperature of peak is lager than on December and than on January, the temperature difference between EWT and LWT is bigger that on January than that on December. The system COP is 3.62.

A Study on the Cooling Heating Performance Experiment by Refrigerant Auto Control of Geothermal Heat Pump (지열히트펌프 냉매자동조절에 따른 냉·난방 성능실험에 관한 연구)

  • Koo, Nam-Yeol;Seo, Seung-Il
    • Journal of the Korean Society for Geothermal and Hydrothermal Energy
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    • v.11 no.1
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    • pp.1-6
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    • 2015
  • This study presents analysis of the experimental data meeting conditions of several applications in real time. The results of this experimental study are as follows: Respectively in cooling and heating performance, a refrigerant charge tank can take automatic control of variation of the refrigerant quantity by controling pressure and temperature of system and outlet water temperature. The COP shows 3.5 in cooling operation and 3.2 in heating operation. The refrigerant quantity increases 0.69 kJ/h. When the outdoor temperature decreases $1^{\circ}C$, Therefore if the temperature become lower from $25^{\circ}C$ to $-16^{\circ}C$, the refrigerant quantity increases about 9.5%. Compared to the normal state experiment results, the COP in automatic control of the refrigerant quantity rises roughly 10%.

A study on the Operating Characteristics of the Capsule-type Ice Storage System (캡슐형 빙축열 시스템의 운전특성에 관한 연구)

  • Kim, Kyung-Hwan;Cho, Sung-Woo;Choi, Jeong-Min;Ha, Suk-Young
    • Proceedings of the SAREK Conference
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    • pp.199-204
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    • 2005
  • The decrease of summer peak electric load of our country is very important. The government is arranging a lot of support policies and statutes. etc. to decrease of peak electric load. And ice storage system is known as one of the alternatives. The purpose of this study is to collect basic data for operating characteristics to plan the most suitable operation of capsule-type ice storage system. The storaging tank is designed to take charge 40% of total cooling load in building, In operation condition the storage tank took charge 50%. Coefficient Of Performance of daily screw refrigerator is around 4.

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Cycle Analysis of 2-Stage Expansion Claude Refrigerator with Turboexpanders (터보팽창기를 이용한 2단 팽창 Claude냉동사이클 해석)

  • Baek, J.H.;Chang, H.M.
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.6 no.2
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    • pp.130-139
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    • 1994
  • A cycle analysis was performed for 2-stage expansion Claude refrigerators by a numerical method. The refrigerators are under recent development such that the reciprocating expanders of Collins cycle are replaced by new turboexpanders. A computer simulation program was written to predict the coefficient of performance of the refrigerators for several input parameters. It was found out that there exist unique optimum values for the ratio of expanded mass through the turboexpanders to the total mass and for the intermediate pressure of the 2-stage expansion. The maximum coefficient of performance was about $5{\times}10^{-4}$ at the optimal operation.

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An Experimental Study on the Supplemental Cooling and Heating Performance Using 1 kW Thermoelectric Module for Vehicle (열전모듈을 이용한 자동차용 1 kW급 보조 냉난방 시스템의 성능에 관한 실험적 연구)

  • Lee, Dae-Woong
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.26 no.5
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    • pp.224-230
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    • 2014
  • The purpose of this paper is to investigate the performance of supplemental cooling and heating system equipped with the 1 kW thermoelectric module. The system consist of 96 thermoelectric modules, heat sink with louver fin and water cooling jacket which is attached on the hot side of the thermoelectric module. The cooling and heating performance test of the thermoelectric system is conducted with various conditions, such as intake voltage, air inlet temperature, air flow volume, water inlet temperature and water flow rate at calorimeter chamber in consideration of environmental conditions in realistic vehicle drive. The experimental results of a thermoelectric system shows that the cooling capacity and COP is 1.03 kW, and 1.0, and heating capacity and COP is 1.53 kW, and 1.5 respectively.

Performance of a Reciprocating Compressor Equipped with Auxiliary Port (보조 흡입구가 장착된 왕복동 압축기의 성능 분석)

  • Lee, Yong-Ho;Kim, Hyun-Jin
    • Proceedings of the SAREK Conference
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    • pp.163-170
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    • 2008
  • Auxiliary port which had been known to be used to reduce the expansion loss of a refrigeration system was applied to a R134a reciprocating compressor in a household refrigerator cycle with an intention of improving the compressor performance. Effects of the auxiliary port on the compressor performance was investigated by a computer simulation program. When a simple hole was made on the side wall of the cylinder as an auxiliary port and surrounding gas inside the compressor shell was assumed to be drawn into the cylinder through the hole, maximum COP improvement of 1.66% was obtained. With auxiliary port equipped with a plate type of check valve, maximum COP was raised to be 1.99%. COP improvement was more distinctive with decreasing the discharge pressure; COP improvement was 5% with discharge pressure of 7 bar.

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