The first element of the project was to establish the peak heating loads from the two large public buildings to be attached to the district heating network. This page details the method used to calculate the heat loss through the buildings during a design winter day and subsequently the peak heating load on the district heating network.

CACULATION METHOD

After all external walls, floors, roofs and glazing areas of each building were summed up, calculations were made to find the peak heating load following procedures in CIBSE guide A. The thermal conductivities of the different materials were used to find the overall heat transfer coefficient of the building, from which the peak load could be determined.

OVERALL PEAK HEATING LOAD:

U values were taken from CIBSE guide A according to the construction materials used in each building. The temperature difference was taken as the largest difference on a cold winter's day in Orkney, in this case 20 degrees Celsius. Ventilation losses, thermal bridging, utilisation factor, internal and solar gains were also taken into account.

For the houses included in Scenario two, peak heat loads were included from the MERIT database which gives values for UK domestic homes.