Performance Analysis of Earth Water Heat Exchanger for Concentrating Photovoltaic Cooling

In the present work, an earth water heat exchanger (EWHE) has been designed for Pilani, Rajasthan (India). The system is designed and simulated in transient analysis tool TRNSYS (v17.0) by varying its operating parameters which includes mass flow rate, length, pipe materials and diameter of buried pipe. The depth-wise temperature of soil has also been evaluated from the simulation and it is found that the depth of 3.5 m is sufficient for pipe burial. The results show that there is an inverse correlation between the pipe length and the EWHE outlet temperature. The comparative study between three different material shows that the performance of EWHE system hardly depends on the properties of these material. Further, the EWHE performance is found to be decreasing with an increase in the mass flow rate from 0.008 kg/s to 0.05 kg/s. The simulated proposed system is then compared with the existing ones in the literature for a given cooling setup of Concentrating Photovoltaic (CPV). It is observed that the proposed system gives better performance than the cooling system given in literature. To achieve the temperature drop from 48.5̊C to 25.5̊C as per the existing CPV setup in the literature, the pipe length of 60 m would be sufficient in the proposed EWHE system. Thus the coupling of EWHE with CPV plants could be economical as well as performance enhancer.