작동유체가 양방향성 태양열 열다이오드의 열성능 변화에 미치는 영향 분석
Effect of Working Fluids on the Thermal Behavior of a Bi-directional Solar Thermal Diode
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An experimental investigation has been carried out to study the effects of different working fluids on the behavior and thermal performance of a bi-directional thermodiode. The thermodiode was made up of two rectangular loops mounted between a collector plate and a radiator plate. Rotatable joints between the horizontal and inclined segments of the loops enable easy alteration of the direction of heat transfer. The loops and the tank were filled with a working fluid for effective heat transfer when the thermodiode was forwarded biased. Six different working fluids were tested with thermal conductivity values ranging from 0.1 to 0.56 W/m-oC, thermal expansion coefficient values ranging from 1.8 x 10-4 to 1.3 x 10-3 K-1, and kinematic viscosity values ranging from 0.65 x 10-6 to 100 x 10-6 m2/s. Especially, mixtures of Al2O3 (30nm particle) in deionized water have been tested for the volumetric ratios of 0.01, 0.02, 0.03, 0.1, 0.2%. Each experiment was carried out after the loop was filled with a working fluid for effective heat transfer and the thermodiode was forwarded biased. The solar thermodiode was heated by a radiant heater consisting of 20 halogen lamps that generated a heat flux of about 1000 W/㎡ on the collector surface. Results are given in terms of temperature development in different parts of the loop as heat is delivered from its hot end to the surrounding atmosphere by the radiator made of copper plates.
Abstract
An experimental investigation has been carried out to study the effects of different working fluids on the behavior and thermal performance of a bi-directional thermodiode. The thermodiode was made up of two rectangular loops mounted between a collector plate and a radiator plate. Rotatable joints between the horizontal and inclined segments of the loops enable easy alteration of the direction of heat transfer. The loops and the tank were filled with a working fluid for effective heat transfer when the thermodiode was forwarded biased. Six different working fluids were tested with thermal conductivity values ranging from 0.1 to 0.56 W/m-oC, thermal expansion coefficient values ranging from 1.8 x 10-4 to 1.3 x 10-3 K-1, and kinematic viscosity values ranging from 0.65 x 10-6 to 100 x 10-6 m2/s. Especially, mixtures of Al2O3 (30nm particle) in deionized water have been tested for the volumetric ratios of 0.01, 0.02, 0.03, 0.1, 0.2%. Each experiment was carried out after the loop was filled with a working fluid for effective heat transfer and the thermodiode was forwarded biased. The solar thermodiode was heated by a radiant heater consisting of 20 halogen lamps that generated a heat flux of about 1000 W/㎡ on the collector surface. Results are given in terms of temperature development in different parts of the loop as heat is delivered from its hot end to the surrounding atmosphere by the radiator made of copper plates.
참고문헌 (18)
- K. Chen, "Solar Energy : New Research, 1st ed." (2006), Nova Science Publishers, Hauppauge, NY
- 오 정무, "태양열 냉난방 및 온수급탕시스 템: 개념, 설계기법 및 경제성 분석 1" (2006)
- Thermo-Diode식 태양열 이 용 모듈 개발(Ⅲ) 연구보고서, "천원기", 통상산업 부, 89~93 (1998)
- H. H. Bau, "On the Stability and Flow Reversal of an Asymmetrically Heated Open", Convection Loop. J. Fluid Mech, 106, pp.417~433 (1981)
- M. Groll, "Development of a Liquid-Trap Heat Pipe Thermal Diode", J. Spacecraft, 16(4), pp.195~202 (1979)
- K. Chen, "The Optimum Configuration of Natural Convection Loops", Sol. Energy, 34(4)통권 : 5, pp.407~416 (1985)
- K. Chen, "On the Oscillatory Instability of Closed-Loop Thermosyphons", ASME J. Heat Transfer, 107(4), pp.826~832 (1985)
- K. Chen, "Design of a Plane-Type", Bidirectional Thermal Diode, ASME J. Solar Energy Engineering, pp.1988, 28(1)[DOI]
- An Energy-Efficient Construction Module of Variable Direction of Heat Flow, Heat Capacity, and Surface Absorptivity, "K. Chen", USAF, ~, pp.USAF Report WL-TR-95-3046 (1995)
- K. Chen, "The Dynamic Behavior of a Bayonet-Type Thermal Diode", Solar Energy, 64(4-6), pp.257~263 (1998)
- 황용하, "재생형 태양열 집열기의 성능에 대한 연구", 충남대학교 논문집, 36(1) (2001)
- B. C. Pak, "Hydrodynamic and heat transfer study of dispersed fluids with submicron metallic oxide particle", Experimental Heat Transfer, 11, pp.151~170 (1998)
- S. P. Jang, "Role of Brownian Motion in the Enhanced Thermal Conductivity of Nanofluids", Applied Physics Letters, 84(21), pp.4316~4318 (2004)
- J. A. Eastman, "Anomalously Increased Effective Thermal Conductivities of Ethylene Glycol-based nanofluids Containing Copper Nanoparticles", Applied Physics Letters, 78(6), pp.718~720 (2001)
- U. S. Choi, "Enhance thermal conductivity of fluids with nanoparticles, Development and application of non-Newtonian flows", ASME FED, 231, pp.MD(66) (1995), 99~105[DOI]
- A. Einstein, "Inverstigation on thetheory of Brownian motion" (1956), Dover, New York
- Y. Xuan, "Conceptions for heat transfer correlation of nanofluids", Int.J. Heat Mass Transfer, 43, pp.3701~3707 (2000)
- Davalos-Orozco, "Hydrodynamic and suspension of polar particles, Encyclopedia of surface and colloid science", 4, pp.2375~2396 (2005)