Application of isobutane - Propane mixtures for heating, and combined heating and cooling in vapour compression systems

Performance of propane and isobutane mixtures in vapour compression systems for heating, and simultaneous heating and cooling applications, is studied. The influence of mixture composition is highlighted leading to the identification of suitable compositions for specific applications. Pressure ratio, pressure difference, compressor discharge temperature, cooling and heating coefficients of performance, volumetric cooling and heating capacities are evaluated. Since temperature glides in evaporator and condensers are inevitable, it is necessary to determine them for possible use in enhancing system performance by matching with the glide of the heat transfer fluid. Based on these parameters, acceptability of hydrocarbon mixtures for the combined heating and cooling, and heating systems are discussed in comparison with those of pure refrigerants such as CFC114, HFC236ea and HFC134a.