Performance Analysis of Salt Gradient Thermal Storage Device Driven by Waste Heat

Generally waste heat is observed as thermal energy source which is produced by every conversion system that has certain efficiency. Mostly, this waste heat is exhausted/dumped to the ambient which causes environmental pollution, potentially energy loss and global warming related issues. Moreover, this waste heat has useful potential and can be further used for different applications after adequate storage. Therefore, a salt gradient thermal storage device (SGTSD) is developed for efficiently storing the recovered waste heat that is generated by the biomass driven engine. The performance of the SGTSD is investigated experimentally through temperature profiles across lower convective region (LCR), non-convective region (NCR) and upper-convective region (UCR), temperature gain, effectiveness of heat exchanger pipe and thermal efficiency. Experimental results showed that calorific value (CV) of syngas varies in the range of 5.31-5.43 MJ/m³ and found very close to the optimum level. The maximum value of waste heat temperature (TWH) is obtained as 396.16 °C at 3 kW and 48 Hz of engine load (We) and frequency (f), respectively. The effectiveness of heat exchanger pipe is found in the range of 0.75-0.77. The maximum achieved temperature in the LCR is found as 65.42 °C corresponding to 396.16 °C of TWH. Thermal efficiency of about 42.31-47.73% is obtained for the developed SGTSD. The attractive outcomes of this study show that the SGTSD could be an effective thermal storage device for the available waste heat that may help to climate control through useful energy production.