热电热泵在非设计工况条件下的性能分析

Analysis on Performance of the Thermoelectric Heat Pump under Off-design Conditions

采用直流电源模拟太阳能电池板输出不稳定电压驱动热电热泵工作。通过实验测试研究了在连续长时间工作、电压跳跃变化和极限电压工况下。热电热泵冷端温度L、热端温度L、冷热端温差L的变化对其制冷／制热的性能系数（COP）的影响。结果表明，在适宜的电压范围内，热电热泵的制冷速度快、工作性能稳定且能够长时间连续工作。而制热效果明显优于制冷效果。制热效率（Eh）平均高于制冷效率（Ec）约0．8；热电热泵的最佳工作电压区间为2～4V，此时的冷端温度低、制冷量大、COP值在理想范围（Eo=0．87～1．89，E=1-75～2．75）；随着工作电压增高，热电热泵的冷热端温差增大，COP值减小。当电压大于8V后。冷热端温差大于45℃，COP值降至最小，工作性能较差。

In the photovohaic and thermoelectric system, the output voltage and current of the solar panels constantly changed with solar irradiance, resulting in the thermoelectric heat pump working under off-design conditions for a long time. To test the performance stability and affordability of the thermoelectric heat pump under off-design conditions, a DC power device replacing the solar panels was used to output unstable current to drive the thermoelectric heat pump. Under three different off-design conditions including continuously working, voltage jumping and limiting voltage, the mutual relation between hot side temperature Th, cold side temperature T,, temperature difference T,~, COP, cooling （heating） capacity and operating voltage wel~ analysed. The results showed that the thermoelectric heat pump refrigerated fast, and it could remain stable. Its heating efficiency was about 0.8 higher than cooling efficiency which indicated that the effect of heating was obviously better than cooling. With the increasing of operating voltage, the temperature difference became greater, but the COP smaller. In addition, the best operating voltage of the thermoelectric heat pump should be between 2 V and 4 V and the effect of heat dissipation had a great influence on the cooling and heating performance of the thermoelectric heat pump.