• Journal of the Korean Institute of Landscape Architecture
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• v.27 no.2
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• pp.19-28
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• 1999

This study quantified shading, evapotranspiration and windspeed-reduction effects of trees on use and cost of heating and cooling energy in two residential neighborhoods of Chuncheon different in tree cover. Annual savings per residence of heating energy were approximately 1,210 MJ(1%) and those of cooling energy, 130 kWh(10%) in study district 1 having tree cover of about 10% . For district 2 with tree cover of about 20%, annual heating and cooling savings were 2,130 MJ(2%) and 180 kWh(19%) per residence, respectively. Trees annually saved energy costs by approximately ￦31,000 ($26, $1=￦1,200) per residence in district 1 and by ￦49,000($41) in district 2. One tree taller than 3 m resulted in annual energy savings of ￦8,000($7) in the study districts. Energy savings by trees in district 2, which had higher tree cover by 10% difference than district 1, were about 2 times greater than those in district 1. This implies that more tree plantings could enhance energy saving effects. Of the total costs saved, 58% was attributed to windspeed reduction and 47%, evapotranspiration. However, shading increased energy costs by 5% due to tree plantings at the wrong locations. Full tree plantings on the west and north of buildings and avoidance of shade-tree plantings of use of solar-friendly trees on the south are recommended to increase building energy savings efficiently.

• Journal of the Korean Solar Energy Society
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• v.31 no.5
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• pp.146-155
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• 2011

Sustainable building is getting more and more important topic in 21C. Following this trend, building energy saving standard has been reinforced in Korea. Especially, insulation standards are revised continuously after1979. This study aims to evaluate the correlation between the revised insulation standards and heating and cooling loads of a residential building. This study shows that the standard of insulation is more related with heating load than cooling load, and cooling load is more related with other sources such as glass types and solar incidence through windows. In case of highly-insulated building such Passive Houses or Zero Energy Houses, the cooling load should also be considered as important as heating load when revising the building energy saving regulations in the future.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.22 no.6
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• pp.392-397
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• 2010

Energy loss from windows accounts for large scores of heating and cooling loads also in energy saving apartments that is reduced over 30% of total energy consumption. Movable reflective insulations, insulation shutters, blinds, insulated shades are used to reduce energy loads from windows. In this study, energy saving performance of insulated shades was simulated by control methods. According to installation of insulated shades, heating loads were decreased about 10.5~11.3%, and cooling loads are decreased about 29.1~38.3% on an energy saving apartment. The heating peak load was reduced about 9.5% by insulated shades and the cooling peak load was reduced about 25.7~31.5%. In the case of insulated shades with automatic control system, simple time schedule control system would be more efficient than outdoor detection control system that should use several sensors.

• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.203-208
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• 2006

The unutilized energy in urban area is commercially and environmentally worth recycling since it can be used as a good energy resource for the heating and cooling supply. Therefore, once heating and cooling demands are near the available unutilized energy resources, a high performance district heating and cooling can be realized by the network of unutilized energy technology. In relation to this circumstance, a road map of the unutilized energy technology is presented in this study.

• Journal of the Korean Solar Energy Society
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• v.32 no.5
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• pp.59-67
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• 2012

In this study,the compact type solar thermal and ground coupled heat pump hybrid system for space heating/cooling and hot water supply has been developed. This hybrid system was installed in Zero Energy Solar House(ZeSH) in KIER for the demonstration. The thermal performance and operational characteristics of this hybrid system were analysed especially. The results are as follows. (1) This hybrid system was designed in order to address the existing disadvantages of solar thermal/ground coupled heat pump system. For this design, all parts except solar collector and ground coupled heat pump were integrated into a single product in a factory. The compact type unit includes two buffer tanks, an expansion tank, pumps, valves, a controller, etc. This system has an advantage of easy installation with simple plumbing work even in narrow space. (2) The thermal charging and discharging time of the buffer tanks and its characteristics by ground coupled heat pump, and heat pump COP according to geo-source temperature and buffer storage temperature have been studied. This system was found to meet well to the heat load without any other auxiliary heating equipment. (3) The operating hours of the ground coupled heat pump as a backup device of solar thermal can be reduced significantly by using solar heat. It was also found that the minimum heating water supply setting temperature and maximum cooling water supply setting temperature make an influence on the heat pump COP. The lower heating water and the higher cooling water temperature, the higher COP. In this respect, the hybrid system's performance can be improved in ZeSH than conventional house.

• Journal of the Korea Institute of Building Construction
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• v.10 no.2
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• pp.97-104
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• 2010

This study evaluated the energy efficiency of a windows system using built-in blinds, with regard to their insulation performance and their blocking of solar radiation. The study took advantage of the "Physibel Voltra" program as a physical simulation of heat transfer. To simulate the "Physibel Voltra" program, I practiced a mock-up test to determine heating quality and translation condition. I analyzed the propensity to annual energy consumption, the annual quantity of heat transfer, and the annual cooling and heating cost through a computer simulation for one general household in an apartment building. In the test, it was found that compared to a general windows system, a windows system with built-in blinds reduced the annual heat transfer by 10% in cooling states and by 11% in heating states when the blind was up. When the blind was down, the windows system with built-in blinds reduced the annual heat transfer by 25% in cooling states and 30% in heating states. When a windows system with built-in blinds is compared with a general windows system, the quantity of cooling and heating loads is reduced by 283.3kw in cooling states and 76.3kw in heating states. This leads to a reduction in the required cooling and heating energy of 359.6kw per house. It is thus judged that the use of a windows system with built-in blinds is advantageous in terms of reducing greenhouse gas emissions, because the annual TOE (tons of oil equivalent) per house is reduced by 0.078TOE, while $tCO_2$ is reduced by $0.16tCO_2$. In addition, compared with a general windows system, the cost of cooling and heating loads in the system reduces the annual cooling cost by 100,000won, and the annual heating cost by 50,000won. Ultimately, this means that cooling and heating loads are cut by 150,000won per year.

• Advances in Energy Research
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• v.4 no.1
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• pp.87-106
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• 2016

In this research, optimum design of the combined solar collector, geothermal heat pump and thermal seasonal storage system for heating and cooling a sample greenhouse is studied. In order to optimize the system from technical point of view some new control strategies and functions resulting from important TRNSYS output diagrams are presented. Temperatures of ground, rock bed storage, outlet ground heat exchanger fluid and entering fluid to the evaporator specify our strategies. Optimal heat storage is done with maximum efficiency and minimum loss. Mean seasonal heating and cooling COPs of 4.92 and 7.14 are achieved in series mode as there is no need to start the heat pump sometimes. Furthermore, optimal parallel operation of the storage and the heat pump is studied by applying the same control strategies. Although the aforementioned system has higher mean seasonal heating and cooling COPs (4.96 and 7.18 respectively) and lower initial cost, it requires higher amounts of auxiliary energy either. Soil temperature around ground heat exchanger will also increase up to $1.5^{\circ}C$ after 2 years of operation as a result of seasonal storage. At the end, the optimum combined system is chosen by trade-off between technical and economic issues.

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.143.2-143.2
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• 2011

Energy foundations and other thermo-active ground structure, energy wells, energy slab, and pavement heating and cooling represent an innovative technology that contributes to environmental protection and provides substantial long-term cost savings and minimized maintenance. This paper focuses on earth-contact concrete elements that are already required for structural reasons, but which simultaneously work as heat exchangers. Pipes, energy slabs, filled with a heat carrier fluid are installed under conventional structural elements, forming the primary circuit of a geothermal energy system. The natural ground temperature is used as a heat source in winter and heat sink in summer season. The system represented very high heating and cooling performance due to the stability of EWT from energy slab. Maximum heat pump unit COP and system COP were 4.9 and 4.3.

• Journal of Power System Engineering
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• v.17 no.6
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• pp.136-141
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• 2013

This study introduces and analyzes the energy for heating and cooling system in region with volcano-stratigraphic. The thermodynamic properties of air through the air blower installed at the entrance of borehole are measured. It estimates the availability of underground air for heating and cooling system through experimental data and theoretical analysis. Based on our conclusion from these calculations we predict possibility of over 40kW steady and stable energy source from underground. Therefore this underground air can be utilized in region with volcano-stratigraphic.

• Journal of the Korean Solar Energy Society
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• v.28 no.4
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• pp.43-49
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• 2008

The purpose of this study is to present the simulation results and an overview of the performance assessment of a solar heating & cooling system by means of the $200m^2$ evacuated tube solar collector. The simulation was carried out using the thermal simulation code TRNSYS with new model of a single-effect LiBr/$H_{2}O$ absorption chiller developed by this study. The calculation was performed for yearly long-term thermal performance and for two design factors: the solar hot water storage tank and the cold water storage tank. As a result, it was anticipated that the yearly mean system efficiency is 46.7% and the solar fraction for the heating, cooling and hot water supply are about 84.4 %, 41.7% and 72.4%, respectively.