休旅車用微型太陽光熱電/吸收式冷卻系統效益解析

Performance Analysis of the Micro Solar Energy on the Thermoelectric/Absorption Heat Pump Cooling

劉啟欣(Chi-Hsin Liu)

指導教授 ： 莊嘉琛

國立臺北科技大學/機電學院/能源與冷凍空調工程系碩士班/碩士(2007年)

摘要

近年來利用熱電原理之車用熱電式冰箱發展迅速，已是相當成熟的商業化產品，也是目前車用冰箱系統的唯一選擇，但熱電式冰箱於休旅車上使用時，僅能以車用12V之電源型式來驅動熱電晶片動作，當汽車停駛的情況下，熱電式冰箱將因失去電力來源而喪失了致冷能力，本文探討以小型太陽能電池做為休旅車用熱電冷卻系統的電力來源，利用太陽能電池面板發電後，驅動休旅車用熱電冷卻系統，以取代傳統使用車用12V之電源型式，讓汽車在停駛的情況下仍能有致冷效果，並考量無日照時將無法達到致冷效果，因此加入一微小型吸收式冷卻系統替代儲電池，以提供無日照時之冷卻能力。
利用電腦程式分別分析模擬熱電式和吸收式系統效能，就太陽電池驅動熱電式冷卻系統中，探討全日照下太陽日照率與電流關係及電流對冷凍能力及COPsol(COPsolar)之影響，可瞭解太陽日照率與最大冷凍能力的特性關係，大或小於某範圍的日照率如何增進冷凍能力，即在最佳值電流(Iopt)時會伴隨著有最大的COPsol值，冷熱端間的溫差增加對COPsol值是沒有幫助的，但當熱端溫度為30°C時可得到最大的COPsol值約0.6左右；而吸收式冷卻系統方面，以單效溴化鋰/水吸收式系統而言，可發現冷凍能力隨著冷凝溫度的增加而降低，在相同的冷凝溫度下，較高的發生器溫度有較佳的冷凍能力，最佳的操作條件下，可得到最佳之COPAHP(COPAbsorption Heat Pump)值約0.78。

關鍵字

太陽電池 ； 太陽熱電 ； 熱電式冷凍 ； 吸收式空調 ； 休旅車

並列摘要

In recent years, thermoelectric principle has been introduced to the automobile thermo-electricity type of refrigerator and this type of refrigerator has also become a rapidly developed and commercialized product. Most of all, it is the only type of system that people adopt at present. Nonetheless, in the case of recreational vehicles, the thermo-electricity type of refrigerator can only drive actions of the thermoelectric chip with the aid of model 12V automobile power. As the automobiles stop, however, the thermo-electricity type of refrigerator loses its cooling function simultaneously since the electric power has been cut. In light of this drawback, this thesis aims to replace the thermoelectric cooling system with micro solar cells as another power source. In this way, automobiles will soon start the thermoelectric cooling system after using the solar cell panel to generate electricity at first. This kind of electricity generation is able to replace the traditional model 12V automobile power. With regard to no sunshine, the automobiles are also equipped with micro absorption heat pump systems to replace the battery in the hope of maintaining cooling ability.
In the application of using solar cells to generate electricity, this thesis aims to respectively use computer programs to analyze and simulate the performance of thermo-electricity type and absorbing type systems. Under the circumstances of sunshine, the thesis probes into the relation between solar insolation rates and electric current as well as discusses the influence of electric current on the cooling ability and COPsol (COPsolar). By recognizing the characteristics between solar insolation rates and the maximum cooling ability, we are able to accelerate cooling ability when it is greater or smaller than certain range of solar insolation rates. The result is as following. The optimum electric current (Iopt) produces the maximum COPsol. To increase the temperature difference is futile to COPsol value. But when the hot side temperature reaches 30°C, it has the highest COPsol value, which is about 0.6. As for the LiBr/H2O absorbing type system, the cooling ability decreases as the condenser temperature increases. While at the same condenser temperature, the optimum cooling ability occurs if the generator temperature is higher. Furthermore, the optimum COPAHP (COPAbsorption Heat Pump) value, 0.78, will also occur in the best operation condition.

並列關鍵字

Solar Cell ； Solar Thermoelectric ； Thermoelectric Cooling ； Absorption Heat Pump system

參考文獻

[6] 張中和、莊嘉琛，”太陽能混元吸收式系統應用效益研究”，國立台北科技大學碩士學位論文，2005年7月，台北。

[9] S.B. Riffat et al."Review thermoelectrics: a review of present and potential applications". Applied Thermal Engineering 23 (2003) 913–935.

[10] Selahattin Goktun."Design considerations for a thermoelectric refrigerator". Energy Convers. Mgmt Vol.36,No.12,pp.1197-1200,(1995).

[11] H. Sofrata."Heat rejection alternatives for thermoelectric refrigerators". Energy Convers. Mgmt Vol. 37, No.3, pp.269-280,(1996).

[12] Gao Min, D.M. Rowe."Experimental evaluation of prototype thermoelectric domestic-refrigerators". Applied Energy 83 (2006) 133-152.