By Bill Watts

26 November 2015

In his recent blog post, Casey Cole suggested that I ‘really, really don’t like heat networks’. That isn’t true.

If Combined Heat and Power (CHP) and district heating were proved to reduce CO2 emissions, reduce the impact of heating on climate change, lower the cost of energy and increase fuel security, in all the circumstances in which they are currently being installed, I would be supporting the associated industries as heroes.

At an industrial scale, CHP is great if linked to a few continuous and large-process heating loads, such as a paper mill for example. In this instance, the system distribution losses are small compared to the heat delivered.

What I really, really don’t like is the thinking that an application that works well in one situation is appropriate for all situations. Let me be clear – the change I want to see is both a realistic assessment of losses to be included in the SAP calculation, and a minimum quality standard regulated and enforced, to ensure these systems are doing what they claim to be doing.

This should not be an emotional argument, but a calculation and judgement based on data.  Engineers are good at that but in the case of district heating they are prevented from using this skill by legislation that as-good-as mandates the use of CHP and district heating in London at least. Furthermore, rather than carry out calculations on actual system losses, engineers are directed by the government SAP calculation tool to assume a system loss of 5%. I contend that this is an impossibly low figure, one that might be appropriate for an industrial heat distribution system but is out by a factor of 10 when it comes to dwellings. If engineers were told to calculate the actual losses, compliance with the government’s targets would be challenging if not impossible.

Read more here.