Restvärmeåteranvändning från absorptionsvärmepumpar
en kartläggning av möjligheter och begränsningar vid Vattenfall Värme Uppsala Block 5
Vattenfall district Heating power plant in Uppsala produces district cooling with absorption heat pumps which leads to a large amount of waste heat that has to be cooled with evaporative cooling towers. The Environmental Court has ordered Vattenfall to survey the possibilities to recover the heat, which is the focus of this thesis.The study begins with an overview of the system, and conditions and limitations for waste heat recovery is examined. In the next step alternatives to recycle the heat is evaluated, either by direct recovering or by upgrading.First, the technical possibility of each alternative is discussed, and then the operation time and the amount of recovered heat is calculated. Those alternatives which are possible are brought further to an economic analysis.The cost of investment for each alternative constitutes the basis for a present value analysis. The results are put together in a table where the total amount of recovered heat is compared with the present value for the different alternatives. Finally, a sensitivity analysis to examine the present values sensitivity for changes in the conditions is achieved.There are several ways heat recovery is possible but it results in high costs. Vattenfall Uppsala has not the ability to absorb large amounts of waste heat and this fact restricts heat recovery considerably.The alternative to let one of the absorption heat pumps recover heat from the flue gas condensation in May and September would save 1.5Mkr/år.