The Norwegian National Team, represented by SINTEF Energy Research, has focused
on CO2 heat pump systems, which are favourable for combined opera¬tion. The
report “Residential CO2 Heat Pumps for Combined Space Heating and Hot Water
Heating – System Design, Test Procedures and Calculation of SPF” by J. Stene
provides, among other things, an overview of possible designs and presents
recommended test conditions and test procedures for B/W CO2 heat pumps for
combined space heating and hot water heating.
The results from the theoretical and experimental PhD study "Residential CO2
Heat Pump System for Combined Space heating and Hot Water Heating" by J. Stene
have also been evaluated in the context of the IEA HPP Annex 28. Figure 1 shows
the principle layout (left) and the prototype (right) of the analysed CO2 heat
pump system. The heat pump unit is equipped with a so-called three-partite gas
cooler for preheating of DHW (A), low-temperature space heating (B) and
reheating of DHW (C). The heat rejection from the tripartite CO2 gas cooler can
be compared with the heat rejection from a conventional heat pump using a
condensate subcooler, a condenser and a desuperheater. The extensive
experimental results have been used to evaluate the COP at varying operating
conditions, compare the system performance with state-of-the-art B/W heat pumps
and derive special testing requirements for the testing of heat pumps using CO2.
A simplified seasonal performance calculation method using fixed source and sink
temperature has also been evaluated.
Figure 1: B/W CO2 heat pump for preheating of DHW, space heating
and reheating of DHW measured in the Norwegian project:
hydraulic scheme (left) prototype (right)
Norway has also
performed test rig measurements for a combined propane heat pump
unit using a desuperheater for hot water heating. The results
are presented in the report “Testing of a Residential
Brine-to-water Propane Heat Pump Unit for Combined Space Heating
and Hot Water Heating”.
The Norwegian participation in IEA HPP 28 has been financed by
the Norwegian company