24 June 2014

A WET-VAPOUR INJECTION AND VARIABLE SPEED SCROLL COMPRESSOR AIR TO WATER HEAT PUMP MODEL AND ITS FIELD TEST VALIDATION


The European government has recognized air, water and ground as renewable energy sources and has indicated heat pumps as the most effective technology to make use
of them. As a consequence a new labeling scheme will clearly compare performances of heat generators by comparing the primary energy consumption factor. ErP (Energy related
Products) directive provides also the methodology and reference normative by which obtaining the ? % value, which is directly related to the seasonal performance factor of the heat pump measured through the EN14825.
The first part of this paper shows results of field testing air to water heat pumps from different installations across Europe. These heat pumps are equipped with the latest development of
variable speed scroll compressor with Wet-Vapour Injection technology. The second part of the paper presents a semi-empirical model. The model is based on compressor data and
heat pump parameters, such as pump and fan power consumption. Further parameters like heat exchanger temperature differences and defrost impact on the efficiency are taken into
account. Field test data are used to validate the semi-empirical model in order to calculate seasonal coefficient of performance (SCOP) of the air to water heat pump. A comparison
with EN14825 calculation method is presented.