University of Strathclyde Biomass Installation Feasibility Tool

Sensitivity Analysis - Heat demand model


For the sensitivity analysis, as a model, it was used a school. It had a length of 30m, width of 40 m, a height of 6 m and two floors. The number of air changes per hour for a building like that, according to the CIBSE guide was set to 1.

During an ordinary day, in the school there are 100 people that use 40 PCs. The intensity of light is 0.01 kW/m2 of floor area. The type of heating is continuous and the heating period is 8 hours for 5 days during summer days, 12 hours for 7 days during winter and 8 hours for 7 days during spring and autumn.

Using a steady state model the design heat losses and energy demand for every month of the year is shown in the following tables and figures.

Two different cases were taken. What changed was the location. In the first case the school was located in east Scotland while in the second one in west Scotland.

For both cases woodchip 2 was selected as a fuel and walking floor as a storage tank.

Design heat loss and heat demand tables and figures

1st case - east Scotland

Heat demand

Figure 1

Heat demand

Figure 2

2nd case - west Scotland

Heat demand

Figure 3

Heat demand

Figure 4

Back to top


The results for both cases are:

1st case – east Scotland

Heat demand

Figure 5

2nd case – west Scotland

Figure 6

From the above two figures it can be noticed a decrease of 5% of the building heat demand in the second case (76 kW from 80 kW). Also the decrease in the fuel cost per year is around 1% (from 14,742 GBP to 14,615). The size of the boiler remains the same.

Back to top