Design of Promising Working Fluids for Emergent Combined Cooling, Heating, and Power (CCHP) Systems
Combined cooling, heating, and power (CCHP) systems enable the simultaneous supply of electricity, heating, and cooling, thus meeting the major energy needs of humans in a single device. Conventional CCHP systems consist of the combination of a prime mover, heating, and cooling system, each of them operating with a thermodynamically suitable working fluid. Recently, novel CCHP cycles, based on the use of a single working fluid for the whole operation, have been proposed. Since the choice of the working fluid represents a design challenge in the development of such technologies, in this work, a product design approach for the selection of suitable working fluids for emergent CCHP applications is presented. A database search is implemented to screen about 60 000 structures included in the DDB, the Design Institute for Physical Properties, and the NIST TDE databases. The screening considers thermodynamic, process-related, constructional, safety, and environmental constraints. Moreover, the tc-PR equation of state is used to ensure the quality of the calculation of thermophysical properties and the performance assessment of promising working fluids. This study shows that flammable fluids such as vinylacetylene or HFC-152 have a good potential for CCHP applications. In the case of reinforced safety restrictions, HCFO-1233zd(E) seems to be an interesting candidate since it is nonflammable and nontoxic.