• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.14 no.11
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• pp.907-913
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• 2002

An experimental study on energy density distributions produced by dish solar concentrating system was performed to optimally design and rightly position a cavity receiver. This deemed also very useful to find and correct various errors associated with a concentrator. It is observed that the actual focal length is 2.17 m with a maximum energy density of 1.89 MW/$m^2$. By evaluating the position of flux centroid, it was found that there are errors within 2 cm from the target center. As a result of the percent power within radius, approximately 90% of the incident radiation is intercepted by about 0.06 m radius. The area concentration ratio normalized to 800 W/$m^2$ insolation and 90% mirror reflectivity was 347 suns. The total integrated power of 2467 W was measured under focal flux distributions, which corresponds to the intercept rate of 85.8%.

• 한국신재생에너지학회:학술대회논문집
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• 2007.06a
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• pp.680-683
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• 2007

In dish concentrating system, natural convection heat loss occurs in cavity receiver. Heat loss mechanisms of conduction, convection, and radiation can reduce the system efficiency. To obtain the high efficiency, the receiver is to absorb the maximum of solar energy and transfer to the working fluid with maximum of heat losses. The convection heat loss is an important factor to determine the system performance. Numerical analysis of the convection heat loss of receiver was carried out for varing inclinaton angle from 0$^{\cdot}$ to 70$^{\cdot}$ with temperature range from 400$^{\cdot}C$ to 600$^{\cdot}C$ using the commercial software package, Fluent 6.0. The result of numerical analysis was comparable with convection heat loss model of solar receiver.

• 한국태양에너지학회:학술대회논문집
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• 2012.03a
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• pp.113-119
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• 2012

The two-step water splitting thermochemical cycle is composed of the T-R (Thermal Reduction) and W-D (Water Decomposition) steps. The mechanism of this cycle is oxidation-reduction, which produces hydrogen. The reaction temperature necessary for this thermochemical cycle can be achieved by a dish-type solar thermal collector (Inha University, Korea). The purpose of this study is to validate a water splitting device in the field. The device is studied and fabricated by Kodama et al (2010, 2011). The validation results show that the foam device, when loaded with $CeO_2$ powder, was successfully achieved hydrogen production under field conditions. Through this experiment, we can analyze the characteristics of the catalyst and able to determine which is more advantageous thing to produce hydrogen compared with previous experiment that used ferrite-device.

• 한국신재생에너지학회:학술대회논문집
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• 2005.11a
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• pp.684-687
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• 2005

KIER has been running a demonstration project for 10kWe solar thermal power generation. the project is to build and operate the first solar thermal power generation system in Korea. For concentrating solar thermal energy $40m^2$ dish type concentrator was adapted and a stirling engine is going to be integrated to the system for power production. At the moment building the dish concentrator including mirror and sun tracking system was completed and it's performance are being closely evaluated. This paper will introduce some detailed designs and construction procedures which we have experienced so far.

• 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.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.8
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• pp.3339-3344
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• 2012

To evaluate solar energy conversion efficiency of a solar power generation system that consists of a dish-type solar receiver in the combination with a Stirling engine, a solar power generation system using a small-sized Stirling engine was developed in this study, and preliminary experiments were carried out. The total capital fee was around five hundred thousand Won, and the developed system was found to produce an electricity of 0.56 kWh corresponding to 10% in the energy conversion efficiency. The better design of the system is expected to improve the system efficiency, and the experimental data obtained in this study will be used for other various applications associated with solar power generation.

• Journal of the Korean Solar Energy Society
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• v.30 no.6
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• pp.118-124
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• 2010

In order to develop commercial model of 10kW dish-Stirling solar thermal power system, modification for the exiting facility was taken for a year as a Leading Project in KIER. During the project, solar tracking system, control and monitoring system and high durability reflector were developed and long term operation were performed. The solar tracking system was tested for four months to investigate the degree of precision and adapted to the control system for an actual operation from October in 2009. The sun tracking accuracy of ${\pm}4$ mrad using modified control system was obtained and the system operated successfully during the experimental period. The monitoring system displays engine pressure, electric generation amounts, generator RPM, receiver temperatures, and etc. from Stirling engine and weather data of Direct Normal Irradiation, Horizontal Global Insolation, wind speed & direction, and atmosphere temperature from weather station. According to the operating results in a clear sky day, electric power of 6,890 W was generated at the DNI value of 850 W/$m^2$ and the averaged solar-to-electricity efficiency during a whole day reached to 18.99%. From the overall operating results, linear power generation trend could be observed with increasing DNI value. The solar-to-electricity efficiency achieved to 19% around the DNI value of 700 W/$m^2$ and increased to 20% when the DNI value goes up to 900 W/$m^2$.

• 한국태양에너지학회:학술대회논문집
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• 2011.11a
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• pp.169-176
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• 2011

The two-step water splitting thermochemical cycle is composed of the T-R (Thermal Reduction)and W-D (Water Decomposition)steps. The mechanism of this cycle is oxidation-reduction, which produces hydrogen. The reaction temperature necessary for this thermochemical cycle can be achieved by a dish-type solar thermal collector (Inha University, Korea). The purpose of this study is to validate a water splitting device in the field. The device is studied and fabricated by Kodama et al (2010, 2011). The validation results show that the foam device, when loaded with $NiFe_2O_4/m-ZrO_2$powder, was successfully achieved hydrogen production with 9 (10 with a Xe-light solar simulator, 2009, Kodama et al.) repeated cycles under field conditions. Two foam device used in this study were tested for validation before an experiment was performed. The lab scale ferrite-conversion rate was in the range of 24~76%. Two foam devices were designed to for structural stability in this study. In the results of the experiments, the hydrogen percentage of the weight of each foam device was 7.194 and $9.954{\mu}mol\;g^{-1}$ onaverage, and the conversion rates 4.49~29.97 and 2.55~58.83%, respectively.