"Greener" heat pumps on the way into office buildings
Svein Tønseth
This is the first ammonia-based heat pump that supplies energy to both heating and cooling in a Norwegian office building.
Statoil decided to use ammonia as a refrigerant in this heat pump in Trondheim.
Without any need for chemicals that deplete the ozone layer or that have a greenhouse effect, it is heating and cooling Statoil's new research centre in Trondheim.
Like most refrigeration systems, a large number of heat pumps have used CFCs (chlorofluorocarbons) as working fluids. By the end of this year, these compounds will no longer be produced in the EU. From then on it will be extremely difficult to obtain CFCs in Norway. New refrigeration systems and heat pumps will therefore have to work with other fluids as refrigerant. New man-made chemicals have been developed as replacements, but none of them are completely environmentally harmless.
On the way in
Natural fluids such as ammonia, on the other hand, do not threaten the ozone layer or the climate. Ammonia-based heat pumps have been installed in industrial plants and a few district heating systems in this country. The first office building installations have taken some time to appear, but ammonia-based systems are now on the way into such buildings. "Ammonia is poisonous, and the fear of panic reactions following leaks has been a psychological barrier for ammonia-based heat pumps in buildings used by large numbers of people. To a great extent this is an irrational fear. If ammonia-based heat pump systems are built in accordance with the rules and regulations, safety is not a problem, says Geir Eggen, who leads SINTEF/NTH's heat pump research.Special study
Gaute Flatheim Consultants, the company which designed the Statoil heat pump system, and the Research Council of Norway, gave the refrigeration technology group at SINTEF/NTH a contract for a special study ahead of the planning phase for the Statoil system. The scientists evaluated the technical, financial and environmental aspects of a number of working fluids. On the basis of their overall evaluation they recommended using ammonia."In the longer term, there are two ways out of the CFC mess. While chemical manufacturers are developing new chemical compounds, at SINTEF/NTH we believe in a transition to natural fluids. The chemical industry have developed substances that do not destroy ozone, but which still have a greenhouse effect. Natural fluids such as ammonia have none of these effects. We are also familiar with the properties of these natural media, so we are not running the risk of environmental effects that are unknown today," says Geir Eggen.