THE BEHAVIOUR OF HEATING SYSTEMS AT OFF-DESIGN CONDITIONS AND THE INFLUENCE ON AMMONIA HEAT PUMP DESIGN PERFORMANCE or HOW WELL CAN A STANDARD AMMONIA CHILLER PERFORM, WHEN USED AS A HEAT PUMP?

摘要

The use of dodgy rules of thumb, combined with lack of overall system understanding, has lead to the overall accepted "fact" that using ammonia as refrigerant in heat pump systems, require either low temperature heating systems or high temperature heat pumps. This "fact" is, in fact, not correct, but has, never the less, virtually banned the use of an extremely efficient refrigerant in heat pump applications. When the heating system is analyzed, designed and run carefully, it is seen that the main bulk of the heat demand is at temperature levels where a standard ammonia chiller, has no problem performing well. We will also show that a little tinkering with the cooling cycle will make a chiller able to deliver hot tap water, with increased cycle efficiency as a result.