IEA Heatpump Programm Annex 28





National project:

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 Shecco Technology.


Norwegian national team – IEA HPP Annex28
sintef National team leader – Jørn Stene
Research scientist
SINTEF Energy Research
Dept. of Energy Processes
7465 Trondheim
Phone: +47-73591642
Fax: +47-73593950
Norwegian heat pump links
shecco Shecco Technology
Shecco Technology has financed the Norwegian participation in IEA HPP Annex 28. Shecco represents an energy efficient and environmentally friendly heating and cooling technology using carbon dioxide (CO2, R744) as the working fluid. Shecco Technology was initiated and patented by the late professor Gustav Lorentzen in 1989 at SINTEF and the Norwegian University of Science and Technology (NTNU). In 1990 Norsk Hydro ASA acquired all commercial rights to Shecco Technology, but the cooperation with SINTEF and NTNU remains close. Shecco Technology is a part of Norsk Hydro ASA.
Novap The Norwegian Heat Pump Association
The Norwegian Heat Pump Association (NOVAP) is an independent organisation which is working for the implementation of heat pumps in the Norwegian energy system. The members of NOVAP are heat pump manufactures, wholesale dealers and suppliers. NOVAP’s main activities are to advance high quality heat pump systems, be a centre of expertise, represent the heat pump business sector in national and international fora, and provide high quality heat pump information to different target groups.
enova Enova SF
ENOVA SF is public enterprise owned by the Royal Norwegian Ministry of Petroleum and Energy. Enova SF`s main mission is to contribute to environmentally sound and rational use and production of energy, relying on financial instruments and incentives to stimulate market actors and mechanisms to achieve national energy policy goals.

last update:22.01.2008

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