• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.24 no.4
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• pp.289-296
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• 2012

The aim of this study is to investigate the performance of a heating and cooling system with aquifer thermal energy storage(ATES heat pump system) known as one of the underground thermal energy storage application systems. The ATES system was composed of heat pump unit and ATES, which was installed in a factory building located in Anseoung. The system represented very high heating and cooling performance, and showed nearly constant COP at each heating and cooling season due to the stability of EWT. The economic analysis about an ATES system and a conventional system was also executed. The conventional system adopted an air-conditioner in the summer season and a LNG boiler in the winter season. The payback period of the ATES system was estimated by 6.62 years.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2001.05a
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• pp.95-99
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• 2001

As a way to use energy effectively, the present study is aimed at investigating the performance characteristics of a Single Effect LiBr/Water Absorption Refrigerator using a low temperature driving heat-source. It was carried out by changing the driving heat-source temperature, the cold water outlet temperature(the refrigeration load), the cooling water inlet temperature, and the weak solution flow rate and this study compares the performance characteristics of refrigerator against the existence and non-existence of the Recirculation of the Weak solution which is used as a method to improve the performance of refrigerator. In case of Recirculation of the weak solution, more improved the Refrigeration Capacity and COP was obtained, and these effects became more larger in the high temperature of driving heat-source and large quantity of solution.

• Journal of the KSME
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• v.17 no.1
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• pp.23-27
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• 1977

태양열을 냉방에 이용하기 위한 시스템은 집열기,열교환기,냉동기 등으로 구성된다. 집열기는 난 방시와 마찬가지로 볼 때 냉난방을 병용하는 집열기를 사용하면 유리하다. 열교환기는 집열기에 서 수집한 열을 냉방기에 전달시키는 기능을 가지는데 용도에 따라 이것을 사용하지 않는 경우도 있다. 냉동기로는 보통 흡수식 냉동기를 사요하나 그외 개방식, 분사식 등의 냉동기도 사용된다. 그러나 분방식 냉동기는 취급은 용이하나 흡수제의 재생조건이 까다로워 높은 습기를 갖는 경우 재생온도가 역시 높아져야 하므로 우리나라의 경우에는 여름철의 습도가 높기 때문에 재생온도가 높아져야 하므로 태양열 냉방에는 부적당하다. 또 분사식 냉동기의 경우 성적계수(Coefficient of Performance) 가 다른 냉동기에 비해 낮고 증기압력이 낮으면 이것이 극히 낮아지기 때문에 태양 열 냉방에 많이 사용하지 않는다. 그래서 태양열 냉방에 있어서 냉동기는 거의 흡수식을 사용하 고 있으며, 여기에서도 주로 흡수식 냉동기를 사용한 냉방에 대하여 논하고져 한다.

• Journal of the Korean Society of Mechanical Technology
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• v.13 no.1
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• pp.113-118
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• 2011

To analyze and verify the effect of replacing thermal storage heater by a cascade cycle heat pump using midnight electricity was installed and tested at a customer's house in Wonju, Korea. The electric night storage heater is consist of 30kW electric heater and 2,700 liters of thermal storage water tank to supply hot water for warming house floor. The power for electric heater was cut off and hot water was only generated by cascade cycle heat pump. Current thermal storage water tank was not eliminated and electric heater wiring was modified. Some operation logic of the heat pump was also modified for proper operation. The required capacity of the heat pump and hot water temperature for given warming condition were estimated. The estimated capacity of heat pump was about 19kW and estimated hot water temperature for proper heating was at least $75^{\circ}C$.

• Journal of the Korean Society of Mechanical Technology
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• v.13 no.3
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• pp.119-124
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• 2011

Electric night storage heater was introduced and disseminated for power grid balancing and efficient management of power generation facility. But fuel cost for heating has been increased rapidly while the cost of electricity increased slightly. This abnormal rate system caused peak load in winter at last. To solve this problem, application of an air source heat pump was suggested. In the study, the effect of replacing night heater by heat pump and the economics were analysed. In addition the expectation of prospect of heat pump penetration was simulated based on surveyed and investigated data. As a result, fund supporting as well as institutional backing was needed for effective propagation and return of investment.

• Journal of the Korean Society of Mechanical Technology
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• v.13 no.3
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• pp.93-98
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• 2011

To analyze and evaluate the performance of developing air to water multi heat pump, the heat pump was installed and tested at low energy house in Daejeon, korea. Heating capacity of heat pump is 16.5KW and cooling capacity is 14.0KW. Space heating/cooling, floor heating and hot water is available. The results performance evaluation of heat pump in lab test showed that the coefficient of performance (cop) was 3.75, and heating capacity was 16.0KW in ambient temperature $7^{\circ}C$. Also at ambient temperature $-15^{\circ}C$, the COP was 1.69. At a low energy house, floor heating is controled by a floor heating water temperature and a room temperature. The COP of heat pump is decreased with frequent on/off operation for controlling of floor heating water temperature.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.20 no.10
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• pp.637-644
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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.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.17 no.3
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• pp.21-29
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• 2021

In this study, the current regulation of the water source energy, one of the renewable energy, was analyzed, and the improvement plan for the high efficient data center cooling system was suggested. In the improvement plan, the design and construction guidelines of the water source energy system permit to adopt the cooling and heating system with or without heat pump. In addition, it should also include the system operated in the cooling mode only all year-round. The domestic test standards to consider the water source operating conditions should be developed. Especially, it is highly recommended that the test standards to include the system with forced cooling and free cooling modes related with the enhanced data center cooling system adopting the water source energy.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.16 no.2
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• pp.176-184
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• 1987

The purpose of this research is to study the characteristics of the coefficient of perform-ance (COP) of the small absorption refrigeration system. This experimental study is performed with two selected variables, the temperature of the generator and the input temperature of the cooling water. In order to determine the input temperature of the generator which gives maximum COP, the experimental data are obtained with controlling the temperature of the generator in the range of $20-32^{\circ}C$ of the temperature of the cooling water. The range of the generator heat suppling temperature which gives maximum efficiency is about $90-95^{\circ}C.$ The temperature range depends on the characteristics of the equipment unit. The most important result in this experiment is the trends of the COP in accordance with the variation of these temperatures. This trend will furnish the informations and knowledges for designing and operating the absorption refrigerator.

• The Korean Journal of Nuclear Medicine Technology
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• v.22 no.1
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• pp.35-42
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• 2018

Purpose Standardized uptake value(SUV) has been widely used as a quantitative metric of uptake in PET/CT for diagnosis of malignant tumors and evaluation of tumor therapy response. However, the SUV depends on various factor including PET/CT scanner specifications and reconstruction parameter. The purpose of this study is to validate a EQ PET to evaluate SUV across different PET/CT systems. Materials and Methods First, NEMA IEC body phantom data were used to calculate the EQ filter for OSEM3D with PSF and TOF reconstruction from three different PET/CT systems in order to obtain EARL compliant recovery coefficients of each spheres. The Biograph true point 40 PET/CT images were reconstructed with a OSEM3D+PSF reconstruction, images of the Biograph mCT 40 and Biograph mCT 64 PET/CT scanners were reconstructed with a OSEM3D+PSF, OSEM3D+TOF, OSEM3D+PSF+TOF. Post reconstructions, the proprietary EQ filter was applied to the reconstruction data. Recovery coefficient can be estimated by ratio of measured to true activity concentration for spheres of different volume and coefficient variability(CV) value of RC for each sphere was compared. For clinical study, we compared SUVmax applying different reconstruction algorithms in FDG PET images of 61 patients with lung cancer using Biograph mCT 40 PET/CT scanner. Results For the phantom studied, the mean values of CV for OSEM3D, OSEM3D+PSF, OSEM3D+TOF and OSEM3D+PSF+TOF reconstructions were 0.05, 0.04, 0.04 and 0.03 respectively for RC. Application of the proprietary EQ filter, the mean values of CV for OSEM3D, OSEM3D+PSF, OSEM3D+TOF and OSEM3D+PSF+TOF reconstructions were 0.04, 0.03, 0.03 and 0.02 respectively for RC. Clinical study, there were no statistical significance of the difference applying EQ PET on SUVmax of 61 patients FDG PET image. (p=1.000) Conclusion This study indicates that CV values of RC in phantom were decreased after applying EQ PET for different PET/CT system and The EQ PET reduced reconstruction dependent variation in SUVs for 61 lung cancer patients, Therefore, EQ PET will be expected to provide accurate quantification when the patient is scanned on different PET/CT system.