Novel system for cooling and electricity: Four different integrated adsorption-ORC configurations with two expanders

In this study, a novel method for integrating adsorption cooling system with ORC to simultaneously generate cooling and electricity utilising low grade heat source is developed by incorporating a steam expander to the adsorption side, so that the system has two expanders in order to increase the amount of power generated. Four different configurations are developed, where in configuration 1 the adsorption system (topping cycle) is powered by an external heat source, while ORC (bottoming cycle) is driven by recovering the heat of adsorption. Configuration 2 is similar to configuration 1 but the ORC is powered using the same heating fluid leaving the adsorption side. In configuration 3, an adiabatic mixer is used to power ORC with the mixture of the leaving heating and cooling fluids, while in configuration 4; the adsorption system (bottoming cycle) is powered using the heating fluid leaving ORC (topping cycle). In this work, advanced adsorption pairs (AQSOA-ZO2/water, Aluminium-Fumarate MOF/water) are investigated and compared to Silica-gel/water while CPO-27(Ni) MOF/water is used in the experimental facility to validate the simulation model. For the ORC side, R245fa, R365mfc, and R141b are used as working fluids. Results show that using configuration 1 can achieve maximum value of the equivalent system COP of 1.17 using Silica-gel/water and R141b and 0.79 using AQSOA-ZO2/water and R141b. In addition, the maximum Specific Power (SP) achieved is 288 W/kgads using AQSOA-ZO2 in configuration 4 and the maximum Specific Cooling Power (SCP) achieved is 552 W/kgads utilizing AQSOA-ZO2 and R141b in configuration 2 and 4. Maximum adsorption power efficiency achieved is 4.3% in configuration 2, while the maximum ORC power efficiency achieved is 18.3% in configuration 4. This work highlights the feasibility of generating cooling and electricity simultaneously from integrated adsorption-ORC system using two expanders.