¶ Solar space heating in group heating systems
Solar space heating for group heating systems is accounted for in DEAP using the method defined here (under “DEAP Tools and Information”).
A group solar space heating system is a group heating system (2 or more dwellings heated by the same heating system) in which some of the dwelling heating load is provided by an array of solar collectors, e.g. an apartment block with a boiler providing space heating and hot water to all the apartments and an array of solar collectors on the apartment building roof which also provides space heating and hot water to each apartment.
It is important to note in this case that the solar space heating system is part of the group scheme and not specific to an individual dwelling. As a result, the Assessor does not need to enter data on the solar collectors in the Water Heating section of DEAP. Instead, the spreadsheet is used to calculate the percentage contribution of the solar collectors to the total heat provided by the group heating scheme. The group solar space heating spreadsheet requires the following data:
Table 11.3 - Data required for solar space heating spreadsheet
| Data Required | Value |
|---|---|
| Total Floor Area | From DEAP Building > Floors tab |
| Main Space Heating System: Delivered Energy | From DEAP View Assessment > Results tab |
| Main Water Heating System: Delivered Energy | From DEAP View Assessment > Results ta |
| Distribution Loss Factor | From DEAP Space Heating > Heat Sources tab (taken from table 10.1) |
| Fraction of heat from CHP unit/recovered from Power Station | From DEAP Space Heating > Heat Sources tab |
| Total floor area of all dwellings served by the group heating scheme | Depends on the development in question. |
| Total aperture area of solar collectors in group heating scheme | From specification |
| Dedicated solar storage volume of group heating scheme | From specification |
| Zero loss collector efficiency of solar collectors | From certified test data or HARP database or Solar hot water |
| Collector heat loss coefficient | From certified test data or HARP database or Solar hot water |
| Annual solar radiation | Taken from Solar hot water |
| Overshading factor | Taken from Solar hot water |
Example
The following example shows data for one apartment in a block of eight apartments (each apartment has a total floor area of 80 m2) with a group heating scheme (a gas boiler) and a group solar array on the apartment building roof. The array has a gross area of 100 m2 which gives an aperture area of 72m2 according to Table H2 - default values from Table H1 are used – and a dedicated solar storage of 5000 litres. The collectors are south-facing at a 30° tilt.
The last line, highlighted in blue, indicates that 34% of the heating provided by the group heating scheme thermal heating comes from the solar collectors. This information must be entered in DEAP for the group heating scheme’s Space Heating section:
In this case, “Renewable and Energy Saving Technologies” entries are not required in DEAP as the space and water heating derived from the group solar heating system is accounted for in full by this “34%” figure. In addition, DEAP uses this figure to calculate any applicable renewable energy contribution for Part L compliance checking.
The Assessor must follow DEAP Appendix A when identifying the main and secondary heating systems operating in conjunction with the solar space heating system or solar water heating system. A main space and water heating system and associated fuel must be specified for individual heating systems always. Likewise, for group heating, at least one fuelled thermal heating system must be specified along with the solar space heating system. The solar space heating will reduce the overall primary energy requirement of the dwelling and this is reflected in DEAP.