Investigation on a mini-CPC hybrid solar thermoelectric generator unit

A hybrid solar hot water and Bi2Te3-based thermoelectric generator (TEG) unit using a heat pipe evacuated tube collector with mini-compound parabolic concentrator (mini-CPC) is proposed. In this unit, the heat from the heat pipe evacuated tube solar collector is transferred to the hot side of TEG. Simultaneously, water cooling is used at the cold side to maintain the temperature difference. Electricity is generated by TEG and the remaining heat is transferred to water at the same time. This paper investigates how to convert excess solar heat into electricity more effectively. A mathematical model regarding this unit is developed and validated. It is found that the mini-CPC can significantly improve the electrical efficiency. The optimal thermal conductance of TEG is determined, which could make the best use of excess solar heat. The excess solar heat can be effectively converted into electricity when ZT of Bi2Te3 can be improved from 100 °C to 200 °C. Using TEG with ZT = 1.0 and a geometrical concentrating ratio at 0.92, electrical and thermal efficiencies of this system are predicted to be 3.3% and 48.6% when solar radiation and water temperature are 800 Wm−2 and 20 °C, respectively.

[1]  Gang Chen,et al.  Theoretical efficiency of solar thermoelectric energy generators , 2011 .

[2]  Enrico Zambolin,et al.  Experimental analysis of thermal performance of flat plate and evacuated tube solar collectors in stationary standard and daily conditions , 2010 .

[3]  S. Tanemura,et al.  Feasibility Study on the Use of a Solar Thermoelectric Cogenerator Comprising a Thermoelectric Module and Evacuated Tubular Collector with Parabolic Trough Concentrator , 2012, Journal of Electronic Materials.

[4]  Yu-Wei Chang,et al.  Thermoelectric water-cooling device applied to electronic equipment , 2010 .

[5]  Graham L. Morrison,et al.  Comparison of fixed asymmetrical and symmetrical reflectors for evacuated tube solar receivers , 1994 .

[6]  Evelyn N. Wang,et al.  Modeling and Optimization of Hybrid Solar Thermoelectric Systems with Thermosyphons , 2011 .

[7]  W. Beckman,et al.  Solar Engineering of Thermal Processes , 1985 .

[8]  Frédéric Lesage,et al.  Optimal electrical load for peak power of a thermoelectric module with a solar electric application , 2013 .

[9]  M. A. Mohamad,et al.  Theoretical analysis of laminar-film condensation heat transfer inside inclined wickless heat pipes flat-plate solar collector , 2001 .

[10]  Wenfeng Gao,et al.  Comparative studies on thermal performance of water-in-glass evacuated tube solar water heaters with different collector tilt-angles , 2011 .

[11]  Ali Shakouri,et al.  Cost-efficiency trade-off and the design of thermoelectric power generators. , 2011, Environmental science & technology.

[12]  Ruzhu Wang,et al.  Comparative study on two novel intermediate temperature CPC solar collectors with the U-shape evacuated tubular absorber , 2013 .

[13]  D. Rowe.  Thermoelectrics Handbook , 2005 .

[14]  Yuehong Su,et al.  Comparative Experimental Analysis of the Thermal Performance of Evacuated Tube Solar Water Heater Systems With and Without a Mini-Compound Parabolic Concentrating (CPC) Reflector(C < 1) , 2012 .

[15]  Gang Chen,et al.  High-performance flat-panel solar thermoelectric generators with high thermal concentration. , 2011, Nature materials.

[16]  Kenneth McEnaney,et al.  Modeling of concentrating solar thermoelectric generators , 2011 .

[17]  Farzad Jafarkazemi,et al.  Evacuated tube solar heat pipe collector model and associated tests , 2012 .

[18]  C.J. Shih,et al.  Optimal design methodology of plate-fin heat sinks for electronic cooling using entropy generation strategy , 2004, IEEE Transactions on Components and Packaging Technologies.

[19]  Ruobing Liang,et al.  Thermal performance analysis of the glass evacuated tube solar collector with U-tube , 2010 .

[20]  K. Sumathy,et al.  Recent advances in the solar water heating systems: A review , 2013 .

[21]  Gang Chen,et al.  Bulk nanostructured thermoelectric materials: current research and future prospects , 2009 .

[22]  Gang Xu,et al.  Efficient, low-cost solar thermoelectric cogenerators comprising evacuated tubular solar collectors and thermoelectric modules , 2013 .

[23]  Ming Qu,et al.  Economic and environmental life cycle analysis of solar hot water systems in the United States , 2012 .

[24]  Yuehong Su,et al.  A study on incorporation of thermoelectric modules with evacuated-tube heat-pipe solar collectors , 2012 .