• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2165-2170
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• 2008

The cooling load in winter season is significant in many commercial buildings and hotels because of the usage of office equipments and the high efficiency of wall insulation. Therefore, the development of a multi-heat pump which can cover heating and cooling simultaneously for each indoor unit is required. In this study, the characteristics and performance of a simultaneous heating and cooling heat pump in the cooling-only and cooling-main operating mode was investigated experimentally with a variation of indoor air dry bulb temperature which is from $21^{\circ}C$ to $35^{\circ}C$. EEV opening was adjusted from 20% to 24% during the tests. When the indoor air temperature varied, the performance in the cooling-only mode was more sensitive to the temperature than in the cooling-main mode. The total capacity and COP were increased by 53.8% and 48.1%, respectively, in the cooling-main, while those were increased by 19.6% and 19.3% in the cooling-only mode. The performance differences between the two operating modes became larger at lower temperatures, especially for the COP.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.19 no.10
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• pp.679-686
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• 2007

The cooling load in winter season is significant in many commercial buildings and hotels because of the usage of office equipments and the high efficiency of wall insulation. The development of a multi-heat pump that can cover heating and cooling simultaneously for each indoor unit is required. In this study, a 4-room simultaneous heating and cooling heat pump system was designed and its performance was measured at each operating mode. The system used R-410A and adopted variable speed compressor. The problems on the designed system were analyzed and defined. In addition, the solutions of the problems were suggested to improve system efficiency and to obtain the stable operation.

• Proceedings of the SAREK Conference
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• 2007.11a
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• pp.370-375
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• 2007

The cooling load in winter season is significant in many commercial buildings and hotels because of the usage of office equipments and high efficiency of wall insulation. The development of a multi-heat pump that can cover heating and cooling simultaneously for each indoor unit is required. In this numerical study, a 4-room simultaneous heating and cooling heat pump system was modeled and its performance was calculated at each operating mode. Also, performance analysis was compared with experimental results.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.20 no.11
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• pp.718-726
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• 2008

The cooling load in winter is significant in buildings and hotels because of the usage of office equipments and the high efficiency of wall insulation. Hence, the development of a multi-heat pump that can cover heating and cooling simultaneously for each indoor unit is required. In this study, the performance of a simultaneous heating and cooling heat pump was investigated in the heat recovery mode (HR mode). The system adopted a variable speed compressor using R410A with four indoor units and one outdoor unit. In the HR mode, the capacity and COP were improved as compared with those in the cooling or heating mode because the waste heat in the outdoor unit was utilized as useful heat in the indoor units. However, energy imbalance between heating and cooling capacity of each indoor unit was observed in the 2H-1C HR mode. Therefore, the performance of the system in the 2H-1C HR mode was enhanced by controlling refrigerant flow rate through the outdoor unit.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.13 no.1
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• pp.7-13
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• 2017

In order to use and manage the building energy efficiently, it is necessary to minimize building energy consumptions, and establish operation plans of various equipment. The maximum heating and cooling load calculation is an essential way in various equipment selections, and the annual building load calculation is used in forecasting & evaluating the LCC required for operation plan. In this study, noting that the annual building load changes depending on outside temperature around year, we propose a predicting method of annual building load. By using the $4^{th}$ polynomial function that have two double radix and a feature the $f(x)=a^4$ in x = 0 condition, we can calculate annual building load very easily only with the two result (maximum heating and cooling load) and a minimum parameters.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.1099-1104
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• 2008

Recent year, mean energy consumptions of a people are higher than other country. And international oil price became over 120 dollar. This energy environment as well as energy war. Maybe, the Meteorological Administration is going to enforce scorching heatwave special report system from that come summer. Besides, 2008 summer, maximum demand power is expected by 64,240,000kW. The electric power equipment reserve rate appeared in to keep 12.5% level. Chilled water storage system witch is one of electric load administration system. Heat pump system used cooling tower heat recovery is advantage that use is possible to summer in small a public bath building. In this paper, we suggest that heat pump system by heat recovery using cooling tower when it is heating operation of ambient air temperature. To apply cooling tower heat recovery heat pump to chilled water heat storage type and achieved performance evaluation about operation. As a result, performance of heat pump system that about 121% in cooling mode, 138% in heating mode higher than KEPCO standard. And heating operation possible to ambient air temperature about $23^{\circ}C$, which of appear cooling tower outlet temperature about $13^{\circ}C$.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.17 no.6
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• pp.696-707
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• 1988

This study simulates a typical solar system using the transient simulation program TRNSYS, and calculates the maximum cooling load of the model room of $50m^2$. In this study, energy rate control method is used in calculating a maximum cooling load. On the ground of the maximum cooling load of the model room, the variables that have an effect on the solar collection performance of the solar system are made a selection. Also in this study the trend of the solar collection performance is shown as the variables change. The results show that the variables which have an effect on the collection performance are collector area, collector mass flow rate, collector slope and the volume of storage tank, and the optimal value of Ac/Vt is not constant but varies as the collector area and the collector mass flow rate. Also the results show that for cooling system the optimal value of the collector slope is latitude minus $15^{\circ}$ during the seasonal operations, and twenty percent of the maximum cooling load is saved with the aid of the solar energy.

• Journal of Bio-Environment Control
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• v.27 no.3
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• pp.269-275
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• 2018

In order to establish the criterion for analyzing outdoor weather conditions in the greenhouse heating and cooling system design, we analyzed heating and cooling design outdoor temperatures by the annual percentile method and compared with design outdoor temperatures by the existing seasonal percentile method. In the annual percentile method, 0.4%, 1% and 2% of the total 8,760 hours per year are presented as cooling design outdoor temperatures and 99.6% and 99% as heating design outdoor temperatures. When the annual percentile method was adopted, heating design outdoor temperatures increased by 6.7 to 9.6% compared with the seasonal percentile method, and cooling design outdoor temperatures decreased by 0.6 to 1.1%. The maximum heating load in the same greenhouse condition decreased by 3.0 to 3.6% when the annual percentile method was adopted, but the effect on the maximum cooling load was insignificant. Therefore, it is necessary to consider the change of heating design outdoor temperatures to the annual percentile method, but it is not necessary to change the cooling design outdoor temperatures since there is little difference between the two methods.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2006.11a
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• pp.306-309
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• 2006

The architectural difference between the existing residence and high-rise residential building causes changes on environmental conditions such as ventilation and insulation. The object of this study is to present the improvement on envelop of high-rise residential buildings to reduce heating and cooling load. To improve the environmental performance of envelop, it is necessary to modify envelop vent system and ensure intermediate space. In this study, the shape of vents in high-rise residential buildings has been inspected, and the survey about the interior environmental conditions related to the envelop of high-rise residential building has been conducted. Environmental measurement has been done to examine out door air quality for natural ventilation.

• Architectural research
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• v.19 no.4
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• pp.89-94
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• 2017

In Korea, it is necessary to improve the performance of buildings with respect to the energy efficiency while improving the quality of occupants' lives through a sustainable built environment. During the design and development process, building projects must have a comprehensive, integrated perspective that seeks to reduce heating, cooling and lighting loads through climate-responsive designs. The aim of this study is to assess the optimal window-to-wall ratio of multi-rise residential units in the early design phase in Korea. The study analyzed the variation of annual heating and cooling energy load in two apartment prototype units located in Seoul city using different WWRs. The analysis was conducted using Autodesk Ecotect Analysis 2011 tool. The study found for total annual building load reductions WWR on the south and north face should be studied independently based on the room function. It also found reducing the WWR for bedrooms and windows on the northern façade resulted in reduced total annual building load.