Effect of heat extraction mode on the overall energy and exergy efficiencies of the solar ponds: A transient study

The main objective of this study is to investigate and compare transient thermal performance of a solar pond under different heat extraction modes. Four different extraction modes were studied: (1) extraction at different rates from LCZ alone, (2) extraction at different rates from NCZ alone, (3) simultaneous extraction from LCZ and NCZ, and (4) simultaneous extraction from LCZ and the ground underlying the pond at different rates. Transient thermal performance of the solar pond was evaluated using a one-dimensional model which was solved using a MATLAB code based on a fully implicit finite-difference scheme that was developed for this particular purpose. The study was focused on examination of thermal performance of the considered solar pond in each of the four heat extraction modes based on energy and exergy analyses. Obtained results revealed higher energy efficiencies with heat extraction from either NCZ alone (29.18%) or a combination of LCZ and the underlying ground (24.92%), rather than that from LCZ alone (17.95%). Therefore, it was concluded that, higher energy efficiency can be obtained by extracting heat from NCZ or a combination of LCZ and the ground underlying the pond rather than following the conventional approach where heat is extracted from LCZ alone.