Integrated adsorption-ORC system: Comparative study of four scenarios to generate cooling and power simultaneously

Adsorption cooling and Organic Rankine Cycle (ORC) systems are promising technologies that can be used to exploit the abundant amount of low grade heat sources such as solar energy, geothermal energy and waste heat from industrial processes. In this study, a two bed adsorption cooling cycle has been integrated with an ORC to simultaneously generate cooling and power utilising AQSOA-ZO2 (SAPO-34)/water and silica-gel/water as adsorption working pairs and R245fa, R365mfc and R141b as ORC working fluids. Four different scenarios of integrated adsorption-ORC system have been investigated, where in the first three scenarios, adsorption system is set up as a topping system, while ORC is set up as a bottoming system. The first one utilized the waste heat of adsorption to power the ORC system with no additional heat and named as Adsorption Heat Recovery Scenario (AHRS). In the second scenario the adsorption return heating fluid is used to power the ORC system (Return Adsorption Heating Fluid Scenario RAHFS). In the third scenario (Heat Exchanger Scenario HES), the cooling and heating sources leaving the adsorption system enter a heat exchanger, where additional heat can be added to the cooling fluid in order to power the ORC system. In the fourth scenario (Return ORC Heating Fluid Scenario RORCHFS), the ORC is considered to be as a topping system, while the adsorption system considered as bottoming system and the return ORC heating fluid can be used to power the adsorption cycle. Results show that when using AHRS, the integrated adsorption -ORC system can achieved system efficiency of 70% using silica-gel/water and R141b and 60% using SAPO-34/water and R141b. In addition, the maximum Specific Power (SP) and Specific Cooling Power (SCP) can be achieved utilising SAPO-34 and R141b with values of 208 W/kgads and 616 W/kgads respectively. This work highlights the potential of using integrated adsorption cooling system and ORC to generate cooling and power simultaneously.