Optimization of a transcritical CO2 heat pump cycle for simultaneous cooling and heating applications.

Energetic and exergetic analyses as well as optimization studies of a transcritical carbon dioxide heat pump system are presented in this article. A computer code was developed to obtain the sub-critical and super-critical thermodynamic and transport properties of carbon dioxide. Estimates for irreversibilities of individual components of the system led to possible measures for performance improvement. The COP trends indicate that such a system is more suitable for high heating end temperatures and modest cold end temperatures. Expressions for optimum cycle parameters have been developed and these correlations offer useful guidelines for optimal system design and for selecting appropriate operating conditions.