Zeotropic mixtures offer the possibility of being changed in composition by rectification methods which can be applied to the control of heat pump systems. Cycle calculations were done with various fluids commercially available in order to find the best mixture combination under the aspect of a wide control range as well as of a maximum achievable COP. A heat pump test rig was built which allowed to change a lot of parameters in order to explore the behaviour of the mixture control with mixtures R32/R125/R227ea and R32/R125/R236fa. Extensive tests with the test rig have been done first concerning mixture control in an air to air heat pump, whereby the heat source ranged down to -15°C and the heat sink temperature to the room was set to 35°C for a room temperature of 21°C. Finally, tests were done on the test rig with the mixture R32/R125/R236fa in order to simulate the behaviour of an air to water heat pump for hydronic heating systems. The vapor-liquid equilibria of the binary mixtures R32/R236fa and R125/R236fa were measured to evaluate the binary interaction parameters and calculate the thermodynamic properties of the mixture R32/R125/R236fa with the Carnahan-Staling-De Santis equation of state. Tests have shown the possibility of a mixture control in a certain temperature range and combined with inverter speed control a much wider control range can be achieved.
Heat pump control with zeotropic mixtures
Bobbo S;Camporese R
1999
Abstract
Zeotropic mixtures offer the possibility of being changed in composition by rectification methods which can be applied to the control of heat pump systems. Cycle calculations were done with various fluids commercially available in order to find the best mixture combination under the aspect of a wide control range as well as of a maximum achievable COP. A heat pump test rig was built which allowed to change a lot of parameters in order to explore the behaviour of the mixture control with mixtures R32/R125/R227ea and R32/R125/R236fa. Extensive tests with the test rig have been done first concerning mixture control in an air to air heat pump, whereby the heat source ranged down to -15°C and the heat sink temperature to the room was set to 35°C for a room temperature of 21°C. Finally, tests were done on the test rig with the mixture R32/R125/R236fa in order to simulate the behaviour of an air to water heat pump for hydronic heating systems. The vapor-liquid equilibria of the binary mixtures R32/R236fa and R125/R236fa were measured to evaluate the binary interaction parameters and calculate the thermodynamic properties of the mixture R32/R125/R236fa with the Carnahan-Staling-De Santis equation of state. Tests have shown the possibility of a mixture control in a certain temperature range and combined with inverter speed control a much wider control range can be achieved.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.