A thermochemical energy storage based cooling and heating system: Modelling, experimental validation and lab-scale demonstration

Abstract

Thermal (heat and cold) energy accounts for over 50% of global final energy consumption and is set to increase, and cooling contributes to 50% of the local electricity peak demands in many places of the world. Therefore, there is a need to develop efficient cooling and heating systems that not only can reduce the power consumption but also shift load to off peak times, offer a better network stability and reducing CO2 emissions at an affordable cost. This work present a thermochemical energy storage based system for cooling and heating provision. The system uses air hydration/dehydration with evaporation cooling concept to generate both cooling and heating, and it can be cascaded to give a wide range of outlet temperature to meet different applications. A single effect and a double effect of the proposed system were numerically investigated using a MATLAB model and experimentally tested under the lab conditions. The modelling results showed that the system level coefficient of performance (COP) depends on the inlet temperature, relative humidity and the recovered energy from the discharging process. At an inlet relative humidity of 45%, the system COP increased from 1.8 to 4.4 when the inlet temperature reduced from 37 °C to 29 °C. The experimental results showed that an outlet temperature of 10–12 °C and 5 °C with an inlet temperature of 30 °C can be obtained, respectively, meaning a temperature reduction respectively by 18–20 °C and 25 °C with the single-stage and double-stage configurations. These results agreed with the MATLAB modelling within 1–3 °C.