• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 추계학술대회 논문집
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• pp.471-476
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• 2007

Effluent ground water overflow in deep and broad ground space building. Temperature of effluent ground water is in $12{\sim}20^{\circ}C$ annually and the quality of that water is as good as living water. Therefore if the flow rate of effluent ground water is sufficient as source of heat pump, that is good heat source and heat sink of heat pump. Effuent ground water contain the thermal energy of surrounding ground. So this is a new application of ground source heat pump. In this study open type and c lose type heat pump system using effluent ground water was installed and tested for it church building with large and deep ground space. The effluent flow rate of this building is $800{\sim}1000$ ton/day. The heat pump capacity is 5RT each. The heat pump cooling COP is $4.9{\sim}5.2$ for the open type and $4.9{\sim}5.7$ for close type system. The system cooling COP is $3.2{\sim}4.5$ for open type and $3.8{\sim}4.2$for close type system. This performance is up to that of BHE type ground source heat pump.

• 설비공학논문집
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• 제9권2호
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• pp.229-238
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• 1997

A third-order simulation model of VM heat pumps has been developed. This model allows consideration of the major losses such as heat conduction losses through regenerators and displacers, pumping losses and wall-to-gas heat transfer losses in working volumes, in addition to the heat exchanger and regenerator losses. The working volume was divided into 12 control volumes and conservation equations of mass and energy were applied to each control volume. Pressure drop was considered in regenerators only. Thermodynamic behavior of working fluid in a VM heat pump was investigated and effects of major losses on the performance of a VM heat pump were shown.

• 설비공학논문집
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• 제8권2호
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• pp.208-218
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• 1996

Performance of a VM heat pump is considerably affected by various losses, such as enthalpy dump, reheat loss, pumping loss, conduction loss and shuttle loss. A second-order analysis model of VM heat pumps, which allows consideration of the major losses, was presented. Actual heat transfer rates for heat exchangers were calculated from the heat transfer rates obtained by the adiabatic analysis and various losses. New effective temperatures of heat exchangers were calculated from the actual heat transfer rates and the mean heat transfer coefficients until there was no appreciable change in the effective temperatures. Effects of design parameters, such as phase angle, swept volume ratio, regenerator length and speed on heating capacity, cooling capacity and COP were shown.

• 설비공학논문집
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• 제15권3호
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• pp.166-176
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• 2003

Experiments have been conducted in order to make comparisons of a alternative refrigerant (R-410A) cycle characteristic with an existing refrigerant (R-22) cycle characteristic in terms of cooling capacity and coefficient of performance (COP). The parameters examined in the present work include air flow rate, indoor/outdoor air temperatures, and indoor relative humidity. These two refrigeration cycles share all components except compressor, accumulator, oil separator, and piping connecting them. The measurements were made using an air-enthalpy calorimeter. The experimental results show that the R-410A cycle has many advantages over indoor conditions while the R-22 cycle has better performance over outdoor conditions.

• 태양에너지
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• 제18권3호
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• pp.15-24
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• 1998

태양열 집열기의 열손실은 크게 3가지 즉 상부 열손실, 하부 열손실, 측부 열손실로 대별되나 단열이 양호한 집열기에서는 일반적으로 측면으로의 열손실은 무시한다. 측부 열손실을 제외한 두 열손실 중에서도 상부 열손실은 집열기의 대부분의 열손실을 차지하는 지배적인 요소이다. 따라서 태양열 집열기의 집열 성능을 정확하게 파악하기 위해서는 상부 열손실 계수를 정확하게 계산할 필요가 있다. 본 연구에서 사용한 평판형 태양열 집열기(재생기)는 하계에는 제습 및 냉방을 행하고 동계에는 난방을 행하는 전천후 집열판으로 제작되었다. 따라서 장치의 전환없이 겨울에 난방용으로 사용하였을 경우의 집열 성능을 파악하기 위하여 옥외에서 실험을 하였다. 동계 기간 실험을 통하여 본 집열기의 상부 열손실 계수는 약 $3{\sim}4.5W/m^2^{\circ}C$임을 알 수 있었다. 그리고 집열표면에 선택흡수막을 입혀서 난방용으로 사용하면 주위와의 복사 열손실을 크게 줄일 수 있기 때문에 본 집열기의 집열 성능을 향상시킬 수 있을 것으로 사료된다.

• 한국산학기술학회논문지
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• 제16권4호
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• pp.2344-2349
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• 2015

여름철이 고온 다습한 우리나라에서는 잠열부하가 크기 때문에 에어컨만을 사용하면 냉방에너지를 많이 사용하게 된다. 이 때에 제습기를 동시에 사용하면 냉방 중 큰 비중을 차지하는 잠열부하를 줄일 수 있어 실내 공기질도 개선하고 냉방에너지도 절약할 수 있다. 본 연구에서는 가정용 제습기에 사용되는 무기섬유 기질에 메탈 실리케이트가 함침된 소형제습 로터에 대하여 항온항습실에서 로터 회전속도, 재생 공기온도, 실내 공기온도, 실내 상대습도, 제습부 전방풍속을 변화시키며 제습 성능을 측정하였다. 제습 로터는 최적 회전수 (1.0rpm)가 존재하며 최적치를 초과하면 불완전 재생 등으로 제습량이 급격히 감소한다. 재생온도가 높아질수록 재생에는 유리하나 제습-재생과정의 열적인 편차가 급격히 증가하여 제습량이 감소한다. 따라서 최적 재생온도가 존재하는데 본 연구의 경우는 $100^{\circ}C$로 나타났다. 상대습도의 증가에 따라 제습량도 증가한다. 이는 제습제의 제습능력이 상대습도에 의존하는 때문이다. 실내 공기온도의 증가에 따라 제습량도 증가한다. 이는 제습측 온도가 높을 때 재생측 공기와의 열적 편차가 감소하여 제습부의 상당량이 제습에만 사용될 수 있기 때문이다. 전방풍속의 증가에 따라 제습량도 증가한다. 이는 전방풍속의 증가에 따라 열 및 물질전달계수가 증가하기 때문이다.

• 설비공학논문집
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• 제27권11호
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• pp.567-573
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• 2015

Commercial buildings account for significant portions of the total building energy in Korea, and thus, a variety of research on chiller operation has been carried out. However, most of the studies were carried out on the chiller itself, i.e., the part load ratio characteristics and the corresponding electricity energy consumption patterns were not analyzed in existing studies. In this study, the part load ratio and the operating characteristics of the vapor compression chiller were analyzed within an office building equipped with the conventional variable air volume system. As a result, significant portions of total operating hours, cooling load, and energy consumption turned out to be in the part load ratio range of 0 through 50%. Thus, energy consumption was significantly affected by the chiller COP at low part load conditions, indicating that chiller operation at the part load is an important factor in commercial buildings.

• 한국지열·수열에너지학회논문집
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• 제3권1호
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• pp.1-9
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• 2007

A steady-state simulation model for Dual-Source Heat Pump(DSHP) of 8RT was presented. A Dual-Source Heat Pump(DSHP) has been designed to make up for the conventional air source heat pumps. The performance evaluation has been conducted under internal standard test conditions such as ISO-13256-1 and KS C 9306. However, as test conditions such as entering water, indoor and outdoor air conditions could not be controlled to satisfy the standard test conditions in outdoor tests, a series of experiments have been conducted with the actual test conditions. Then, computer models for DSHP could be used for the standard condition have developed using EES program. The model was developed from basic thermodynamic principles and heat transfer relations. Most of the parameters were obtained with EES from the actual catalog data. The simulation results were in good agreement with the experiments.

• 한국수소및신에너지학회논문집
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• 제25권3호
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• pp.297-304
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• 2014

The purpose of this study is to evaluate the experimental performance characteristics of a water-to-water geothermal heat pump featuring a vapor refrigerant injection for the production of hot water. The performance of geothermal heat pump with a vapor injection was evaluated by comparing with that of a conventional geothermal heat pump without a vapor injection. For heating operation, the geothermal heat pump with a vapor injection is superior in COP and heating capacity. The vapor injection was more effective for supplying hot water while overloading. The vapor injection was effective for the improvement of the cooling capacity. However, the vapor injection was not effective for the increasing of COP according to the increased input of a compressor. The advantage of vapor injection in water-to-water geothermal heat pump become disappeared while cooling operation with lower part loading.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2009년도 하계학술발표대회 논문집
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• pp.52-57
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• 2009

This paper describes the multi-heat pumps applied in an ground source heat pump system for an actual building. The performance of a ground source multi-heat pump installed in the field was investigated at heating season. The average COP of the systems with single U-tube and double tube type GLHXs were 4.8 and 5.0, respectively. It is needed to investigate the long term performance of double tube type GLHX, because the reduction of inlet temperature of OD HX for this GLHX was larger than it for U-tube GLHX.