• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.12
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• pp.82-90
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• 2019

This analysis demonstrates the effective removal of heat generated from a solar panel's output degradation factor solar cells (the solar panel's output deterioration factor), and solves the problems of oxidation and corrosion in existing metal heat sinks. The heat-dissipating test specimen was prepared using carbon materials; then, its thermal conductivity and its effectiveness in reducing temperatures were studied using heat transfer numerical analysis. As a result, the test specimen of the 30g/㎡ basis weight containing 80% of carbon fiber impregnated with carbon ink showed the highest thermal conductivity 6.96 W/(m K). This is because the surface that directly contacted the solar panel had almost no pores, and the conduction of heat to the panels appeared to be active. In addition, a large surface area was exposed to the atmosphere, which is considered advantageous in heat dissipation. Finally, numerical analysis confirmed the temperature reduction effectiveness of 2.18℃ in a solar panel and 1.08℃ in a solar cell, depending on the application of heat dissipating materials.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.165-168
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• 2008

A numerical analysis was conducted to predict the heat transfer characteristics of a solar receiver which is subject to very high heat fluxes and temperatures for solar thermal applications. The concentration ratio of the solar receiver ranges 1000 and the concentrated heat is required to be transported to a certain distance for specific applications. This study deals with a solar receiver according to internal geometry variation incorporating high-temperature heat pipe. The isothermal characteristics in the receiver section is of major concern. The diameter of the solar thermal receiver was 120 mm and the length was 400 mm and the angle of receiver end wall set $90^{\circ},\;60^{\circ},\;45^{\circ},\;30^{\circ}$. And the diameter of the heat pipe was 12.7 mm, 48 axial channels of the same dimensions were attached to the outer wall of the receiver with even spacing in the circumferential direction. The channels are changed to high-temperature sodium heat pipes. Commercial softwares were employed to deal with the radiative heat transfer inside the receiver cavity and the convection heat transfer along the channels. The numerical results are compared and analyzed from the view point of high-temperature solar receiver.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2094-2099
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• 2008

A numerical and experimental studies are carried out to investigate the transient heat transfer characteristics of 5kWth dish-type solar air receiver. Measured solar radiation and temperatures at several different locations are used as boundary conditions for numerical simulation. Many parameters' effects (reflectivity of the reflector, the thermal conductivity of the receiver body, transmissivity of the quartz window, etc.) on the thermal performance are investigated. Discrete Transfer Method is used to calculate the radiation heat exchange in the receiver. A transient heat transfer model is developed and the rate of radiation, convection and conduction heat transfer are calculated. Comparing the experimental and numerical results, good agreement is obtained. Using the numerical model, the transient heat transfer characteristics of volumetric air receiver for dish-type solar thermal systems are known and the transient thermal performance of the receiver can be estimated.

• 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.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2100-2105
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• 2008

A numerical analysis was conducted to predict the heat transfer characteristics of a high-temperature, high heat flux solar receiver as the end-wall angle varied. The concentration ratio of the solar receiver ranges from 200 to 1000 and the concentrated heat is required to be transported to a certain distance for specific applications. This study deals with a solar receiver incorporating high-temperature sodium heat pipe as well as a typical one that employs a molten-salt circulation loop with the same outer dimensions. The isothermal characteristics in the receiver section is of major concern. The diameter of the solar thermal receiver was 120 mm and the length was 400 mm. FLUENT, a commercial software, was employed to deal with the radiative heat transfer inside the receiver cavity and the convection heat transfer along the channels and heat pipes. The numerical results were compared and analyzed from the view point of heat transfer characteristics the solar receiver system.

• 한국태양에너지학회:학술대회논문집
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• 2008.11a
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• pp.226-231
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• 2008

The heat transfer characteristics of a solar high-temperature receiver with heat pipes was investigated by numerical simulation. The concentration ratio of the solar receiver ranges 1000 and the concentrated heat is required to be transported to a certain distance for specific applications. This study deals with internal geometry variation of a solar receiver incorporating high-temperature heat pipe. The isothermal characteristics in the receiver section is of major concern. The diameter of the solar thermal receiver was 120 mm and the length was 400 mm. The angle of receiver end wall was varied between $0^{\circ}$ and $45^{\circ}$. The wall thickness of the heat pipe channel was 4mm and 48 axial channels of the same dimensions were attached to the outer wall of the receiver with even spacing in the circumferential direction. The channels are changed to high-temperature sodium heat pipes. Commercial softwares were employed to deal with the radiative heat transfer inside the receiver cavity and the conduction heat transfer along the channels. The numerical results are compared and analyzed from the view Point of high-temperature solar receiver.

• New & Renewable Energy
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• v.4 no.4
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• pp.72-79
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• 2008

A numerical and experimental studies are carried out to investigate the transient heat transfer characteristics of 5kWth dish type solar air receiver. Measured solar radiation and temperatures at several different locations are used as boundary conditions for numerical a. Many parameters' effects (reflectivity of the reflector, the thermal conductivity of the receiver body, transmissivity of the quartz window, etc.) on the thermal performance are investigated. Discrete Transfer Method is used to calculate the radiation heat exchange in the receiver. A transient heat transfer model is developed and the rate of radiation, convection and conduction heat transfer are calculated. Comparing of the experimental and the numerical results, results of both are in good agreement. Using the numerical model, the transient heat transfer characteristics of volumetric air receiver for dish type solar thermal systems are known and the transient thermal performance of the receiver can be estimated.

• 한국신재생에너지학회:학술대회논문집
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• 2008.10a
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• pp.167-170
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• 2008

A numerical and experimental studies are carried out to investigate the transient heat transfer characteristics of 5kWth dish type solar air receiver. Measured solar radiation and temperatures at several different locations are used as boundary conditions for numerical simulation. Many parameters' effects (reflectivity of the reflector, the thermal conductivity of the receiver body, transmissivity of the quartz window, etc.) on the thermal performance are investigated. Discrete Transfer Method is used to calculate the radiation heat exchange in the receiver. A transient heat transfer model is developed and the rate of radiation, convection and conduction heat transfer are calculated. Comparing the experimental and numerical results, good agreement is obtained. Using the numerical model, the transient heat transfer characteristics of volumetric air receiver for dish type solar thermal systems are known and the transient thermal performance of the receiver can be estimated.

• 한국태양에너지학회:학술대회논문집
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• 2008.11a
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• pp.238-244
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• 2008

A numerical and experimental studies are carried out to investigate the heat transfer characteristics of 5kWth dish-type solar air receiver. Measured solar radiation and temperatures at several different locations are used as boundary conditions for numerical simulation. Many parameters' effects (reflectivity of the reflector, the thermal conductivity of the receiver body, transmissivity of the quartz window, etc.) on the thermal performance are investigated. Discrete Transfer Method is used to calculate the radiation heat exchange in the receiver. A heat transfer model is developed and the rate of radiation, convection and conduction heat transfer are calculated. Using the numerical model, the heat transfer characteristics of volumetric air receiver for dish-type solar thermal systems are known and the thermal performance of the receiver can be estimated.

• Journal of the Korean Society of Propulsion Engineers
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• v.21 no.5
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• pp.29-36
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• 2017

In this study, a numerical analysis is made of the fluid flow and heat transfer characteristics in the solar arrays of HALE (High Altitude Lond Endurance) UAV. In the stratosphere where UAV operates, high level solar radiation is induced, heat transfer decreases due to natural convection and forced convection is dominated by ambient flow. In order to predict the solar array temperature range in this environment condition, the conjugate heat transfer analysis was carried out for the solar arrays on the main wing. The investigation focused on the temperature distribution of solar array and heat transfer characteristics according to influence of solar energy, flight condition as vehicle speed, air density, temperature.