Effect of heat extraction on the thermal efficiency of salt gradient solar pond

Abstract

In this paper, the experiment simulates the salt gradient solar pond with heat extraction and that without heat extraction, setting temperature sensors in the solar pond to monitor the temperature change of each measuring point in real time, extracting heat in the low convective zone and nonconvective zone at the same time. The experimental results show that heat extraction can improve the heat storage capacity of solar pond. The heat storage of solar pond with heat extraction is 40.3% more than that without heat extraction according to the experimental results. The heat extraction can increase the overall thermal efficiency of the solar pond; the efficiency of solar pond with heat extraction and that without heat extraction is 22.2 and 28.7%, respectively.

Advances in solar pond technology and prospects of efficiency improvement methods

“…This involves integrating heat exchangers that can efficiently transfer heat from the lower convective zone to external applications. These exchangers must be designed with materials that withstand corrosive environments and optimized for minimal disruption to the salinity gradient (Jaefarzadeh, 2006;Wu et al, 2019). Moreover, the design of these systems should accommodate the thermal load requirements of the intended applications, ensuring maximum utilization of the stored energy.…”

“…On the other hand, higher temperatures, especially at the top convective layer, can lead to increased heat losses due to evaporation or radiation, which can decrease the overall efficiency of the solar pond as the stored heat energy is lost to the environment (Andrews & Akbarzadeh, 2005). Therefore, while a higher temperature in the storage zone is beneficial for storing more solar energy, it is also crucial to maintain the temperature gradient and minimize heat losses to enhance the overall efficiency of a solar pond (Valderrama et al, 2022;Verma & Das, 2020;Wu et al, 2019).…”

“…As the water at the bottom heats up, it rises to the surface, releasing its stored heat into the environment. Consequently, much of the captured solar energy is dissipated before it can be effectively stored or harnessed, limiting the potential of solar ponds as reliable energy sources (Alcaraz et al, 2016;Sathish & Jegadheeswaran, 2021b;Wu et al, 2019). Hence, industrial-scale applications would require further research and development to increase solar ponds' performance (Kasaeian et al, 2018).…”

“…The salt concentration gradient of NCZ increases downwards, and its thickness is more than that of other zones. The NCZ acts as an insulating layer to prevent heat loss in the upward direction, and its thickness depends on the desired temperature, solar transmission properties, and thermal conductance of water (Wu et al, 2019). The bottom layer of the LCZ is where the absorbed radiation is transformed and stored in the form of heat.…”

Performance Evaluation of Solar Power Plants: A Review and a Case Study

“…In recent years several solar power plants have been built in this province. The all-high fiord of the Yazd province is described by a high annual direct normal radiation of 2511 kWh/m 2 [114][115][116].…”