Shell-and-tube based thermal energy system coupled with flat plate solar collector.

Abstract

To secure optimum utilisation of solar energy sources, a novel shell-and-tube heat exchanger with multi-tube passes and extended surfaces based latent heat storage (LHS) system was designed, developed and commissioned with an integration to flat plate solar collector in Organic Rankine Cycle (ORC). Paraffin, HFE-7000 and water were employed as thermal storage material and heat transfer fluids to sustain simultaneous generation of electricity and heat. It was noticed that the melting/solidification rates and charging/discharging powers were significantly augmented with an increase in Stefan number. However, an increase in Reynolds number had offered a moderate enhancement. The proposed design solution proficiently captured and released 14.35 MJ and 13.63 MJ while charging and discharging at constant inlet temperature for 3 h and 1.5 h, respectively. It was deduced that heat and electricity demands for domestic and industrial applications could be achieved and supplied by regulating inlet operating conditions of LHS system and/or by assembling LHS systems in series or parallel combinations.