• Journal of the Korean Solar Energy Society
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• v.32 no.2
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• pp.19-27
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• 2012

This paper describes an experimental study on efficiency of solar collector in solar water heating system connected to hourly water heating load. In general, the functional form of solar efficiency is expressed as a function of fluid temperature entering solar collector, ambient temperature, and solar irradiance. When energy saving from solar heating of water heating system is analyzed on along-term basis such as one year with given solar irradiance data, simplified analysis is more convenient han detailed system simulation for quick assessment. However, the functional form of the efficiency is not convenient for approximately simplified energy analysis because the inlet temperature can be obtained through a detailed system simulation. In the study, solar collector efficiency is obtained with various daily water heating load sand daily solar irradiance using experimental tests. The study also considers large residential buildings such as apartment buildings for application of solar water heating systems. From test results, it is found that daily solar collector efficiency is proportional to daily water heating loads and daily solar irradiance. The data obtained from the study can be utilized to find a functional relation between daily solar irradiance and daily heating load in stead of collector inlet temperature for application of solar collector efficiency to long-term approximated energy analysis of solar heating system.

• Journal of the Korean Solar Energy Society
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• v.22 no.4
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• pp.1-9
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• 2002

This study is on the design and evaluation of Zero Energy Solar House(ZeSH) including active solar heating system. Various innovative technologies such as super insulation, passive solar systems, super window, ventilation heat recovery system...etc were analyzed by individual and combination for the success of ZeSH. The ESP-r simulation program was used for this. Simulation results shows that almost 77% of heating load can be reduced with the following configuration of 200mm super insulation, super windows, passive solar system and 0.3 ventilation rate per hour. Active solar heating system (ASHS) was designed for the rest of the heating load including hot water heating load. The solar assisted heat pump is used for the auxiliary heating device in order to use air conditioner but not included in this study. The yearly solar fraction is 87% with a solar collector area of $28m^2$. The parametric studies as the influence of storage volume and collector area on the solar fraction was analyzed.

• Journal of the Korean Solar Energy Society
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• v.28 no.6
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• pp.15-23
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• 2008

The article deals with system technology of a new solar heating system which systematically combines exiting solar collector technology, auxiliary electrical water heating, floor heating system and well insulated construction method and its application of this system to apartment house heating system in the cold region, and also analyzed performance of the new system in terms of technical and economic feasibility. Results shows that energy efficiency approaches up to 50% of the energy consumption of local construction from 1980 to 1981. The implementation of "DQ technology" to floor heating system achieved from 79% to 85% of the energy-saving benefits comparing to other housing units which were supplied by the local district heating plant.

• 한국태양에너지학회:학술대회논문집
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• 2009.04a
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• pp.203-208
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• 2009

This paper presents demonstration study results derived through field testing of a solar assisted cooling and heating system for the library of a cultural center building located in Gwangju, Korea. The area of demanded cooling and heating for building was about 350m2. Solar hot water was delivered by means of a 200m2 array of evacuated tubular solar collector (ETSC) to drive a single-effect (LiBr/H2O) absorption chiller of 10RT nominal cooling capacity. From March in 2008 to February in 2009, demonstration test were performed for solar cooling and heating system. After experiments and analysis, this study found that solar thermal system was 84% for the solar hot water supply and 12% for space heating and 4% for space cooling.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.663-668
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• 2008

This study was carried out solar heating system design for district heating and it's the performance analysis by experiment. This experimental system was installed in Bundang district heating area in the end of 2006. The flat plate and vacuum tube solar collector are combined in one system. So district heating water is heated first by flat plate solar collector and than by vacuum tube solar collector. This solar heating system has not a solar buffer tank and is operating with variable flow rate to obtain a setting temperature of $90{\sim}95^{\circ}C$. As a result, the daily solar thermal collection efficiency is about 30 to 40% for the plate type and 50 to 55% for the vacuum tube solar collector. It varied especially depend on the weather condition like as solar radiation and ambient temperature. This variable flow rate system can be also reduced much pumping power more than 50%.

• Solar Energy
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• v.2 no.1
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• pp.49-58
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• 1982

Aim of this study was to obtain the heating performance and the economic evaluation on solar heating system for greenhouse which area of floor was $90m^2$. For heating performance effective solar energy for the greenhouse was compared with overall heating loads including coefficient of heat transfer and conduction. And the economic evaluation solar heating system was evaluated by comparison its initial investiment costing with oil saving cost. Initial investiment costing included collector cost, storage cost, piping cost, control system cost and miscellaneous costs which included pumps, motors etc. The contents of this study included the survey of climate conditions for solar heating, long-term collector performance and optimum collector area of solar heating system in existing greenhouse. The results are follows: 1. Average horizontal radiation during winter was $2,434Kcal/m^2$ day which was the highest value in this country, so the climate conditions of Suwon was suitable for solar heating. 2. Resulting calculation of the optimum collector area was $30m^2$ and the solar energy accounted for 30% of the overall heating load. 3. The capacity of storage tank required 60 liter per unit area ($m^2$) of solar collector.

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.1215-1219
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• 2009

In this study, the performance of solar assisted hybrid heat pump system with cloud cover were analyzed by using experimental method in spring season. It was consisted of concentric evacuated tube solar collector, heat medium tank, heat storage tank, heat pump, and so on. As a result, the solar radiation should be maintained over $4.1\;MJ/m^2$ in order to operate solar heating system for heating. Solar heat of collector wasn't affected by ambient temperature, but cloud cover has a big effect to collector efficiency. In addition, the collector efficiency is about 50-60%, and solar fraction is 40% for this system.

• Journal of the Korean Solar Energy Society
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• v.28 no.6
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• pp.64-69
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• 2008

In this study the thermal performance and economic analysis program of solar heating system for district heating was developed. This program, named SOLAN-DHS and based on TRNSYS, consisted of four modules like as user's interface for system input/output, library, and utilities and a calculating engine. SOLAN-DHS simplifies user's input data through the database of most system engineering data including weather data of 17 areas in Korea. Five different types of solar systems which can be applicable to district heating system were presented in this program. Due to the user-friendly layout, all design parameters can be changed quickly and easily for the influence on system efficiency. The reliability of SOLAN-DHS was finally verified by the experiments.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.8 no.4
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• pp.221-236
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• 1979

The three years Performance of a liquid type solar heating system has been determined for a system which has been determined for a system which has been operating continuously since 1976 in Seoul with no serious maintenance. A flat plate collector is used to transform incident solar radiation into thermal energy. This energy is stored if the form of sensible energy and used as needed to supply the space heating loads. An electric auxiliary heaters are provided to supply energy for space heating load when the energy in the storage tank is depleted. The ratio of useful collected solar heat divided by the total solar radiation on the collector was obtained about 84 per cent. It is also obtained the relation between ratio of solar collector area to the heating area and the ratio of useful collected solar energy to the heating load for the useful design data. A comparison between the measured and simulated results with the solar space heating system is described. Hour by hour simulation is made on unsteady state basis using the system parameters and meteorological data at the experiment site. The result of comparison turned out satisfactory for the solar heating system, though the simulation was formed somewhat higher than by experimental.

• Journal of the Korean Solar Energy Society
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• v.28 no.5
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• pp.21-27
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• 2008

In this study, the design of the solar heating system for district heating as well as it's operating characteristics and the performance analysis was carried out. This solar district heating system was composed of two different types of solar collector circuit, flat plate and vacuum tube solar collector, in a system. This system supply constant temperature of hot water without solar buffer tank. For this, the proportional(variable flow rate) control was used. The experimental facility for this study was used the Bundang district solar heating system which was installed in the end of 2006. The operating characteristics and behaviour of each collector circuits are investigated especially for the system design and control. The yearly solar thermal efficiency is 47.5% on the basis of aperture area and 39.8% on the basis of gross area of collector. As a result this solar heating system without solar buffer tank and with proportional controller was testified a very effective and simplified system for district heating. It varied especially depend on the weather condition like as solar radiation and ambient temperature.