Eqvivalent temperature control of heat supply in multi-family dwellings

Abstract

The possibilities to save money, improve the indoor thermal climate and decrease emissions when implementing weather forecast control for heating in multi-family dwellings are studied in the thesis. Computer simulations in IDA ICE 4 are used and case studies are performed in order to find the possible savings. Conventional control with outdoor sensors only and equivalent temperature control without weather forecast are the two reference systems for comparison. The differences in result when having functioning and non-functioning thermostatic radiator valves are also investigated. The construction of weather forecast control is described in more general terms in the theory part and the self-constructed weather forecast control implemented in IDA is furthermore described in detail. The building simulated in IDA is a multi-family dwelling constructed in three floors with a concrete frame, built in the early 1970’s. The simulations are performed using the most weather exposed apartment in the building. Both the simulation in IDA and the case studies indicate that weather forecast control can save 15 kWhheat/(m2∙year). Implementing weather forecast control in a conventional system regulated by outdoor air temperature control and with no thermostatic valves functioning saves almost the same amount of energy as if new thermostatic valves would have been installed, according to the results from IDA. Calculating the total net savings shows that installing new thermostatic valves is somewhat better than weather forecast control. The net savings per year when installing new thermostatic valves and using weather forecast control is 331 SEK and 290 SEK respectively in the apartment simulated. Installing weather forecast control in a conventionally controlled building with all thermostatic valves functioning is not economically feasible when using the self-constructed equivalent temperature in IDA.