Experimental investigation of eutectic phase changing materials (KCL + Na2SO4) mixed with graphene (Gr) nano-particles on refrigeration test rig

Abstract

There has been increasing interest of various researchers in sustainable solutions towards HVAC and R. As we know that Indian refrigeration market has had remarkable growth of around 8.1 % Compound Annual Growth Rate (CAGR) over the period 2021–27. In India, several industries introduced deep freezers, refrigerators, refrigerated trucks for the preservation of different commodities like fruits, veggies, milk, Ice-cream, meat, medicines, etc., at 0 to 15 °C temperature. Thus, an attempt has been given on energy-saving opportunities for power saving by considering the above scope of refrigeration and cold chain applications. In this context, the present research is to prolong the cooling period during a power outage and minimize the losses which are occurred due to temperature fluctuations of the evaporator cabinet of the refrigeration test rig by using Nano-phase change material (KCl + Na2SO4 + Graphene) with water as base fluid. The experimental setup is tested during power ON and OFF conditions and performance is studied on the basis of cooling time, power consumption, and COP. The dispensability of nanoparticles and PCM is observed with the help of Scanning Electron Microscopy (SEM). The experiments were tested for 1 % and 5 % (KCl + Na2SO4 + Graphene) Nano-PCM mixture and it has been found that the addition of graphene nanoparticles in phase change material results in an enhanced heat transfer as well as improvement in 12 % COP. Also, power consumed with the advancement of Nano-PCM in the evaporator side is 10 % lesser than that of the conventional one. It is observed that with the use of 5 % (KCl and Na2SO4) addition of 1 % (Gr) with water as the base fluid it is possible to maintain 7 to 9 degrees for 13 to 15 hrs time span even though a power outage exists. The temperature range 5 to 10 degree is standard temperature for storing the fruits, veggies and medicine/vaccine. It is observed that thermal energy storage by using Nano-phase changing material for lower temperature application is the most appropriate way and method to correct the gap between the demand and supply of energy in cold chain applications.