A large absorption heat pump

Abstract

In November 1984 the first large absorption heat pump (AHP) in Sweden was installed. The AHP delivers 7 MV heat to a district heating system, using excess steam as drive energy and cooling water as heat source. The steam and the cooling water originate from a near by chemical plant aswaste energy. The heat pump is manufactured by SANYO. It is one of the largest AHP (type I) in the world so far.The generator is heated with 10 bar steam and in the evaporator, water is cooled from 60\ub0C to 30\ub0C. The heat pump raises the temperature of the district heating water from 60\ub0C to 80\ub0C. The working pair used is Lithium bromide-water. A single control loop reduces the steam flow when the temperature of the district heating waterexceeds 83\ub0C.In this paper the energy balances and internal behavior of the heat pump are presented. The energy balances were continuously determined from temperature and flow recordings every other minute in the external streams of the AHP. The internal behavior - such as heat transfer - have been studied by means of surface temperature sensors. The COP was found to vary between 1.3 and 1.8 with a mean value of 1.6. Since startup the availability has been 100 %. The AHP is very flexible with load variations between 0 % and 100 % without complications. Corrosion has been avoided by means of inhibitors and a purge pump system