Replacement of R22 in Existing Installations: Experiences from the Swedish Phase Out

The phase out of R22 as working media in refrigerating machines and heat pumps in Sweden began in 1998 with a stop for new installations. From January 1st 2002 a refill stop takes effect. A project called Replacement of R22 in new and existing facilities – energy efficiency, economy and environmental consequences within the Swedish Energy Administrations research programme Climate 21 (Klimat 21) was finished early in 2001. The experiences from this project, along with other work at the department for the last 15 years, makes out the base for the present work. In the beginning of the 1990s when phasing out CFCs like R12, there was a substitute available; a substitute with properties so close to those of R12 that a change could be done without any significant loss off performance. This substitute is R134a. The problems that did occur were mainly connected to lubricants and materials compatibility, i.e. retrofit methods. When the phase out of R22 became an issue there were no single substitute with properties so close to R22 as R134a are to R12. The new working fluids are zeotropic refrigerants, thus introducing new phenomena, difficult to handle and understand. The good experiences from the CFC phase-out could not easily be transferred to the new situation. All commercially available and accepted substitutes influence the performance and behaviour of the facility extensively. Thus, focusing on the refrigerant alone will not solve the problems for the owners or users, and a wider perspective has to be chosen to obtain the most environmentally benign solution: A solution that also results in the best possible economical solution for the owner. I.e. this is not just a question of replacing a chemical. The present work shows that energy efficiency and capacity of e.g. a refrigerating machine very seldom are maintained when only a change of refrigerant has been done. By expanding the perspective to include the whole installation of which the machine is a part and look at the need and demand of the user – as well as the possibility to alter these – the prospect of conducting a retrofit with the best energy efficiency, least influence on the environment and the best total economy for the user, increase. INTRODUCTION Refrigerant Phase-out and retrofit is a highly cross-disciplinary problem requiring competences from many different scientific and engineering fields. Several aspects of mechanical and chemical engineering such as materials compability, tribology, thermophysical properties, heat transfer characteristics etc. determine the suitability of a new refrigerant, replacing a historically accepted alternative. The aim of this paper is to present general experiences from refrigerant retrofit activities in Sweden during 1989-2001. It also illustrates the need for increased competence in service companies and for users and the displacement of decisions from a central body of consensus to a plant specific system decision when dealing with the replacement of HCFC22. The optimal solution of the problem may requires changes in the wider system context by other measures not directly related to the substitute of a refrigerant to another, i.e., other measures may prove to be more cost-effective to the