This diploma work covers an investigation over the heat - and hot water systems of the

tenant-owner's association, Bogården. The heat - and hot water needs of Bogården are

satisfied by both district heating as well as three heat pumps. Implemented investigation

shows that the heat pumps are not used in a profitable way. Apart from that, the reserve

possibilities are small. There is also a risk of the growth of Legionella bacterium in the

hot water system.

Since the heat pumps are already installed, HSB-Gävleborg (responsible for Bogården)

has a wish to investigate possible proposed actions for optimization of existing plant.

After completed investigation, a new proposed action is presented. The new proposed

action goes on intercepting the hot water production and using the heat pumps to only

heat production during the heating season. Why the hot water production should be

intercepted, is just in order to eliminate the risk of Legionella. Besides, the new proposal

is going to bring about a reserve of 1,534,000 SEK during a twenty-year period. This is

approximately twice as much as what the existing plant may bring during the same

period.

During the work's review, it also has been established that heat - and hot water systems

are error regulated. Since the diploma work does not cover that piece it is instead

informed as proposals subject to further investigation.