• 대한기계학회논문집B
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• 제34권2호
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• pp.191-196
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• 2010

기존의 증기압축식과 흡수식을 결합한 하이브리드 히트펌프는 $50^{\circ}C$정도의 저열원에서 $80{\sim}90^{\circ}C$의 온수를 효과적으로 생산할 수 있다. 본 연구에서는 EES를 사용하여 2단 압축 하이브리드 히트펌프와 1단 압축 하이브리드 히트펌프의 성능을 비교하였다. 동일한 작동조건에서 2단 압축 하이브리드 히트펌프는 1단 압축 하이브리드 히트펌프보다 약간 높은 COP를 가지며 더 안정적인 상태에서 운전이 가능한 것으로 나타났다. 2단 압축 하이브리드 히트펌프에서 작동 유체의 최대 온도는 1단 압축 하이브리드 히트펌프보다 40K정도 낮게 나타났으며 이는 윤활유의 작동에 무리없는 운전상태를 가능하게 한다. 1단과 2단 하이브리드 히트펌프 모두 UA값이 증가할 때 COP는 감소하였으며 열출력은 증가하였다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 춘계학술대회 초록집
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• pp.197.2-197.2
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• 2010

The study on the operation characteristics of solar space and water heating system with ground source heat pump (GSHP) as a back-up device was carried out. This system, called solar thermal and geothermal hybrid system (ST/G), was installed at Zero Energy Solar House II (KIER ZeSH-II) in Korea Institute of Energy Research. This ST/G hybrid system was developed to supply all thermal load in a house by renewable energy. The purpose of this study is to find out that this system is optimized and operated normally for the heating load of ZeSH-II. Experiment was continued for seven months, from October to April. The analysis was conducted as followings ; - the contribution of solar thermal system. - the appropriateness of GSHP as a back-up device. - the performance of solar thermal and ground source heat pump system respectively. - the adaptation of thermal peak load - the operation characteristics of hybrid system under different weather conditions. Finally the complementary measures for the system simplification was referred for the commercialization of this hybrid system.

• 설비공학논문집
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• 제25권7호
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• pp.406-412
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• 2013

A hybrid heat pump is under development with the goal of utilizing 120% of primary energy resources. A plate heat exchanger is added between the compressor and air-cooled condenser of an ordinary heat pump to heat water. For successful operation of the heat pump, it is necessary to develop a control algorithm under various operating conditions. As a virtual test bed for that purpose, a dynamic model has been developed, to simulate its dynamic behavior. It was modeled in transient one-dimensions, with varying phase lengths considered. The model was implemented in Matlab and Simulink. Simulation results were effectively applied to design a control algorithm. They also provided physical insight into how to design and operate the system.

• 한국태양에너지학회 논문집
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• 제33권2호
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• pp.1-10
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• 2013

Simulation study of a solar hybrid heat pump using R744 and R22 for residential applications was carried out according to heat pump operating temperature, outdoor temperature and solar radiation. As a result, when the heat pump operating temperature increases from $40^{\circ}C$ to $48^{\circ}C$, the COP of a R744 and R22 heat pump system decrease from 2.15 to 1.7 and from 3.09 to 2.69, respectively. Besides, as the outdoor temperature rises from $3^{\circ}C$ to $11^{\circ}C$, the COP of R744 and R22 heat pump system increase from 1.73 to 2.12 and from 2.73 to 3.02. When the solar radiation increases from 10 to 20 $MJ/m^2$, the collector operating time and collector efficiency of R744 heat pump increase 10.3 times and 50.7%, respectively. The performance of R744 solar hybird heat pump is more sensitive to operation condition compared to that of R22. Besides, the solar heating system is more effective to the R744 heat pump system.

• 한국지열·수열에너지학회논문집
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• 제7권1호
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• pp.45-50
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• 2011

Hybrid desiccant cooling system(HDCS) consists of desiccant rotor, regenerative evaporative cooler, heat pump and district heating hot water coil. In this study, TRNSYS and EES, dynamic and steady simulation programs were used for studying hybrid desiccant cooling system which is applied to an apartment house from June to August. The results show that power consumption of the hybrid desiccant cooling system is 70 kWh in June, 199 kWh in July and 241 kWh in August. Sensible and latent heats removed by the hybrid desiccant cooling system are 300 kWh, 301 kWh in June, 610 kWh, 858 kWh in July and 719 kWh, 1010 kWh in August. COP of the hybrid desiccant cooling system is 8.6 in June, 7.4 in July and 7.2 in August. COP of the hybrid desiccant cooling system decreases when latent heat load increases. Operation time of the system is 70 hours in June, 190 hours in July and 229 hours in August. Since the cooling load is largest in August, the operation time of August is longest for maintaining the indoor temperature at $26^{\circ}C$. Due to the characteristics of hybrid desiccant cooling system for efficiently handling both sensible and latent loads, this system can handle sensible and latent heat loads efficiently in summer.

• 한국지열·수열에너지학회논문집
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• 제8권1호
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• pp.7-12
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• 2012

This study proposes a hybrid geothermal system combined with heating mode and snow-melting mode for winter season in order to increase the annual operating efficiency of the GSHP(Ground Source Heat Pump). The purpose of this study is to get effectiveness of the hybrid geothermal system by the site experiments. In case of snow-melting only mode, the GSHP COP is 0.7 higher than system COP in average. And in case of hybrid mode, heating GSHP COP is 0.5 higher than snow-melting GSHP COP. And it is also found out that all COP obtained through measurement periods is higher than nominal COPs given by GSHP manufacturer. As a conclusion, it is clear that the proposed hybrid geothermal system is expected as a highly efficient system.

• 설비공학논문집
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• 제23권10호
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• pp.678-686
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• 2011

Simulation study on the operating characteristics in the solar hybrid R744 heat pump system for residential applications was carried out with heat pump operating temperature, outdoor temperature and solar radiation. As a result, collector operating time is decreased by 1.5 hours due to the increase of water temperature in the heat storage tank when the heat pump operating temperature rises. Heat pump operating time is reduced by 19.4% owing to the high temperature of a heat storage tank. Besides, indoor heating time is decreased from 10.3 to 5.5 hours as the indoor temperature increases from $3^{\circ}C$ to $11^{\circ}C$. In addition to, when the solar radiation rises from 10 to 20 MJ/$m^2$, the maximum outlet temperature of a solar collector is increased from $65^{\circ}C$ to $71^{\circ}C$.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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• pp.42-47
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• 2008

This paper reports the system performance of a hybrid plant, which combines a renewable energy plant of GSHP(Ground Source Heat Pump) with a conventional plant (screw water chiller). To find out operational cost and operating characteristics, the performance of the hybrid system was measured in a building located in Jeju island. Based on the measured data, the operating characteristics were analyzed and the operational cost was estimated by using payment table, which was provided by the Korea Electric Power Cooperation. Operating methods to save energy were recommended.

• 한국수소및신에너지학회논문집
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• 제27권2호
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• pp.182-191
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• 2016

In the present work, a solar assisted heat pump (SAHP) system with a hybrid collector was analyzed. For this, a simplified thermodynamic model was developed. Based on the proposed model, the heat transfer rate, COP, and the annual operating hour of the SAHP system were estimated. The effect of the variation of system design parameters on the performance of the system was also examined. From the results, the performance was improved with increasing the effectiveness of heat exchangers and decreasing the difference between the evaporation temperature and the outlet brine temperature of the hybrid collector loop. Finally, the performance of SAHP system with a hybrid collector was compared with that of conventional serial and parallel SAHP systems. The SAHP system with a hybrid collector was substantially better than a series system and slightly worse than a parallel system for both the yearly averaged heat transfer rate and COP. However, the annual operating hour of the SAHP system with a hybrid collector was much better than that of a parallel system.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 춘계학술대회 논문집
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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.