CPL - Chalmers Publication Library
| Utbildning | Forskning | Styrkeområden | Om Chalmers | In English In English Ej inloggad.

Calculation methods for comparing the performance of pure and mixed working fluids in heat pump applications

Marine Högberg (Institutionen för värmeteknik och maskinlära) ; Lennart Vamling (Institutionen för värmeteknik och maskinlära) ; Thore Berntsson (Institutionen för värmeteknik och maskinlära)
International Journal of Refrigeration Vol. 16 (1993), 6, p. 403-413.
[Artikel, refereegranskad vetenskaplig]

Three methods for comparing cycle performance of working fluids, pure as well as non-azeotropic mixtures, are investigated for two applications and for two mixture pairs, HCFC22-CFC114 and HCFC22-HCFC142b, and their pure components. The methods differ in the way of calculating the heat exchange processes. They assume, respectively, equal minimum approach temperatures, equal mean temperature differences and equal heat transfer areas. Changes of coefficient of performance (COP) with composition are explained for all methods. It is shown that transport properties must be taken into account when making rigorous comparisons between working fluids. To predict the relations between fluids with high accuracy, one must use the method with equal heat transfer areas. By the method with equal mean temperature differences, the COP can be estimated with the same accuracy for mixtures as for pure fluids, and can be used for rough estimations of the COP level with different fluids. The method of equal minimum approach temperatures should be avoided for non-azeotropic mixtures.

Nyckelord: heat pump; refrigerant; non-azeotropic mixture; HCFC22; CFC114; HCFC142b; heat transfer; COP; calculation



Denna post skapades 2011-11-25. Senast ändrad 2015-02-11.
CPL Pubid: 148983

 

Läs direkt!


Länk till annan sajt (kan kräva inloggning)


Institutioner (Chalmers)

Institutionen för värmeteknik och maskinlära (1949-2002)

Ämnesområden

Kemiteknik

Chalmers infrastruktur