Operation of a portable cooling system integrated with thermal storage using a natural refrigerant.

Buildings have been identified as one of the most promising sectors for energy saving. An innovative portable cooling system (PCS) using vapor compression cycle is being developed to reduce building energy consumption in the range of 10-30%. The present article focuses on understanding the performance of this PCS with R290 as the refrigerant, in comparison to R134a which is currently used in the prototype. The condenser heat is stored in a helical coil heat exchanger embedded in PCM. The resultant processes of melting and solidification in PCM involve varying effects of natural convection and conduction. Empirical heat transfer coefficient (within 10% uncertainty) for melting is measured experimentally and then used in a dynamic Modelica-based model of the PCS, which is validated with experimental data. The model is then used to predict the operation with R290 to identify benefits and shortcomings of switching the refrigerant.