IES-VE User Forum

I’m currently modelling a building for SBEM Compliance. The building is split into two blocks(Block A and Block B) which are physically separate from each other. The heating/hot water in Block A is served via CHP/ gas condensing boilers. Block B is served from the plantroom in the Block A. I have completed a separate model for each block. When inputting the services for Block B I assume I will have to treat the heating/ hot water as a district heating system. I’ve been asked for the CO2 conversion factor, would anyone have any information on how to calculate this?

Any help would be greatly appreciated.

The value but should equal the kgCO2 emitted by the scheme per kWh of heat delivered to your building. Thus it should encompass the generator efficiency of the district heating plant, the carbon emission factor of the fuel used, any transmission losses between the district heating plant and your building, and also the carbon offset achieved by the CHP unit due to generated electricity. You might use an equation such as this as a guideline for arriving at the value of the CO2 conversion factor:

[CEF(gas) - (CEF(elec)*(CHP elec efficiency)] / [CHP thermal efficiency * delivery efficiency * heat exchanger losses] = kgCO2/kWh

Further, there is some limited guidance given in ADL2A but this is the extent of the published guidance I've seen on the subject.

I hope this helps.