Technical procurement of heat recovery systems in existing apartment blocks in Sweden

摘要

The installation of heat recovery systems is one of the most importantmeasures to save energy in existing apartment blocksand presents a technical potential of up to 5 TWh savings peryear in Sweden. Today, most apartment blocks built before 1975are ventilated by natural ventilation or mechanical exhaust ventilation,while heat recovery is seldom used. Components andsystems exist, but require development and adaptation if theyare to be suitable for widespread use in rebuilding projects. Inaddition, rational methods need to be developed to cover ordering,design, rebuilding and administration.In order to help to start a market for heat recovery systems,five local housing companies in Sweden, in conjunction withSABO (Swedish Association of Public Housing Companies)and the Swedish Energy Agency, announced a technical procurementproject for exhaust air heat recovery systems. Thepurpose of the project is to kick-start development and marketavailability of energy-efficient system solutions for suchsystems in the run-up to the coming extensive rebuilding ofapartment blocks.A technical specification has been produced with a call fortenders for installation of systems in seven demonstrationblocks. Two nominated bids have been taken forward. An efficientair-to-air heat exchanger-based system with an visuallyacceptable duct system that is easy to install in the apartments.The other bid uses a heat pump to recover heat from the exhaustair, which efficiency is improved by a condenser.Preliminary results show that it is possible to produce effectivesolutions for heat recovery from ventilation exhaust airin existing apartment buildings, and that it will be possible toreduce costs. Designs and methods have been developed thatenable such systems to be installed in apartments with a minimumof disturbance for the tenant. The start of a market rangeof heat recovery systems in refurbishment seems to be establishedin near future.