• Solar Energy
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• v.12 no.2
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• pp.9-17
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• 1992

This is an experimental work concerning about an application of a heat pipe to an evacuated-glass-tube solar collector system. A methanol heat pipe with length of 0.7 m and diameter of 8 mm was manufactured and tested to compare its performance with that of freon thermosyphon which was originally used in a solar collector system fabricated at Thermomax Co.. Then this methanol heat pipe was utilized to be one component, i.e. heat transfer element, of the present experimental model of a solar collector. This model was performed the operation test as its absorber plate was irradiated by infrared lamps. The following results were obtained. (1) The methanol heat pipe was showed a stable operation when the variation of axial heat transport was $0{\sim}40$ watts and that of inclination angle was $30{\sim}90^{\circ}$. (2) The heat transport capability of the heat pipe was proved to be higher than that of the thermosyphon, because the heat transport limitation of the latter was occured at about 30 watt. (3) The heat pipe in a solar collector was also showed good performance as it transmitted absorbed energy.

• 한국태양에너지학회:학술대회논문집
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• 2012.03a
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• pp.274-279
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• 2012

Daegu Solar Power Tower Plant of 200 kW thermal capacity was developed for the first time in Korea, 2011. Measurement of the heat flux distribution is essential to evaluate the solar energy concentrated by reflectors and to design a suitable receiver. The flux mapping technique, which uses a radiometer and a diffuse plate, is common for measurement of the heat flux distribution. Because the solar power tower plant has a wide concentration area, the flux mapping technique using a fixed diffuse plate is difficult to apply. Therefore, the flux distribution in the solar power tower plant should be measured by the flux mapping technique using a small moving bar. In this study, we measured flux distributions with the moving-bar system developed at the KIER solar furnace and evaluated its applicability for the solar power tower plant.

• 한국태양에너지학회:학술대회논문집
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• 2012.03a
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• pp.451-456
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• 2012

This study was carried out to evaluate thermal performance of the renewable hybrid heat supply system with solar thermal system and wood pellet boiler for Zero Carbon Green home of apartment houses. The hybrid heat supply system was set up at Korea Institute Energy Research in 2011. The system was comprised of the wood pellet boiler unit with heat capacity designed as 20,000 kacal/hr, a evacuated tubular solar collector 3.74 $m^2$ of aperture area at the $20^{\circ}$ install angle, a 0.3 $m^3$ hot water storage tank, a 0.15 $m^3$ hot water storage tank for space heating. Thermal performance tests for one-house of apartment house were carried out by hot water load and heating load in winter season through the hybrid heat supply system. As a result, hot water energy supplied by the hybrid heat supply system was 11kWh in a day. Solar thermal energy portion was 2.99kWh which is 27% of the total hot water energy supply. wood pellet boiler supply portion was 8.017kWh which is 73% of the total hot water energy supply.

• 한국태양에너지학회:학술대회논문집
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• 2011.04a
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• pp.223-228
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• 2011

The volumetric solar receiver is a key element of solar power plants using air. The solar flux distribution inside the receiver should be a priori known for its heat transfer modeling. Previous works have not considered characteristics of the solar flux although they change with radiative properties of receiver materials and receiver geometries. A numerical method, which is based on the Monte Carlo ray-tracing method, was developed in the current work. The solar flux distributions inside multi-channeled volumetric solar receivers were calculated when light is concentrated at the KIER solar furnace. It turned out that 99 percentage of the concentrated solar energy is absorbed within 15 mm charmel length for the charmel radius smaller than 1.5 mm. If the concentrated light is assumed to be diffuse, the absorbed solar energy at the charmel entrance region is overpredicted while the light penetrates more deeply into the charmel. The developed method will help understand the solar flux when only a part of concentrated light is of interest. Furthermore, if the presented results are applied for heat transfer modeling of multi-channeled volumetric solar receivers, one could examine effects of receiver charmel properties and shape on air temperature profiles.

• Solar Energy
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• v.20 no.3
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• pp.61-73
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• 2000

Heat losses from receivers for a dish-type solar energy collecting system are numerically investigated. The analytical method for predicting conductive heat loss from a cavity receiver is used. The Stine and McDonald Model is used to estimate convective heat loss. Two kinds of techniques for the radiation analysis are used. The Net Radiation Method that is based on the radiation heat balance on the surface is used to calculate the radiation heat transfer rate from the inside surface of the cavity receiver to the environment. The Monte-Carlo Method that is the statistical approach is adopted to predict the radiation heat transfer rate from the reflector to the receiver. Based on the heat loss analysis, the performance of two different receivers for multifaceted parabolic solar collectors with several flat facets can be estimated, and the optimal facet size is obtained.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1995.05a
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• pp.78-81
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• 1995

In the present study, the spray column type of direct contact heat exchangers are studied experimentally to analyze heat transfer characteristics for solar energy utilization. These experiments are carried out in the line of solar heating system, major results are as follows ; 1) the flow and aspect of working fluid drop for maxium heat transfer 2) efficiency and volumetric heat transfer coefficient of D. C. H. X. with a heavier working fluid are higher than those of D. C. H. X. with a lighter working fluid

• Journal of the Korean Solar Energy Society
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• v.35 no.3
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• pp.65-71
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• 2015

A solar thermal simulator is suitable for indoor experiments of solar receivers and reactors when solar insolation and weather conditions are not favorable. Moreover, due to the easy control of electric power input, the solar thermal simulator allows the adjustment of power input incident on solar receivers and reactors and thus the implementation of accurate experiments. We manufactured a solar simulator, which is comprised of three sets of a xenon lamp and an elliptical reflector. In order to serve as a test facility, optical characterization of the solar simulator via radiation heat flux measurement is a critical prerequisite. We applied the flux mapping method to measuring the heat flux distribution of the three lamps. We presented the measurement results in terms of the heat flux distribution, the peak heat flux, the power distribution, the maximum power, and the efficiency for electric power conversion into radiation power. Characterization results show that our solar simulator provides the peak heat flux of $3,019kW/m^2$, the maximum power of 16.9 kW, and the conversion efficiency of 45%, additionally with a 10% operation margin for output increase.

• Journal of the Korean Solar Energy Society
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• v.33 no.6
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• pp.39-46
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• 2013

This work introduces a simple one-reactor adsorption desalination system that harnesses low temperature heat sources (solar energy, waste heat), which has been experimentally studied to elicit the most suitable design parameters and operating conditions. The design process of the system was divided into three parts to reflect the operating principle of desalination technology with application of adsorption processes. First, the evaporator for the vaporization of saline water was designed, then the reactor for the adsorption and release of the steam, followed by the condenser for condensation of the fresh water. The specific water yield is measured experimentally with respect to the time while controlling parameters such as heat source temperatures, coolant temperatures, system switching and half-cycle operational times. The present system well demonstrates the applicability of silica gel in relation to adsorption technologies that utilize low temperature heat sources ranging from 60 to $80^{\circ}C$, such as solar energy and waste heat.

• Journal of Bio-Environment Control
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• v.1 no.1
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• pp.14-20
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• 1992

For the high quality and low cost agricultural crops in greenhouse cultivation, it is necessary to use natural energy as much as possible. In order to reduce the fossil fuel consumption and maximize the solar energy utilization in greenhouse heating, a latent heat storage material was developed as a relatively highly concentrative solar energy storage medium. And a solar energy-latent heat storage system was designed and constructed. The experimental research on greenhouse heating effect of the system was performed.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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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.