carbon limited

Last week, Bill Watts at M&E practice Max Fordham wrote a passionate rant against CHP and heat networks on the Construction Manager website.

The crux of Bill’s message is that real world losses on new build projects are higher than losses calculated using manufacturers’ specs and SAP. How much higher? Bill’s not sure – he says that only ESCOs know how well or how poorly heat networks are working. But in any case “much higher than we’ve been led to believe.”

A few days after the original article appeared, Construction Manager ran a follow up piece in which people from the building industry try to rebut Bill’s argument. In general the respondents make the case that CHP and DH have an important role to play in decarbonising heat, with several highlighting that the Heat Network Code of Practice should improve the performance of new networks.

But in my view the industry respondents missed the key point.

It’s clear Bill really really dislikes heat networks. You can hear it in his melodramatic language about government seeing DH as “the panacea to all our future energy woes” or claiming that policymakers just “don’t care about costs or losses.” This is an emotional argument with few numbers to back it up.

And there’s the problem: Bill makes his argument based on dogma, not data. And if you’ve read much of this blog, you’ll know that that really gets my goat.

At this point you might say: of course he’s making an emotional appeal; with no data, what else could he do? Bill despairs that only ESCOs have data on how heat networks are performing. He laments that “if the CHP and district heating industry fails to indicate what [DH] losses are, it makes predicting the viability of these systems very difficult.”

But performance data isn’t locked up in some ESCO vault. We’re not denied access to data by the CHP and DH industry. The data is right there on site – in every heat meter in every flat. It’s in the check meters in the plant room and on network branches: a little stash of gold dust building up each day from the moment the meters are installed. Including on those heat networks designed by Fordhams, of which there are plenty.

Fordhams is “working with existing systems, designing them themselves, and reviewing reports and designs by other consultants.” How? In an information vacuum? With no clear performance targets and verified results? If the engineers are blind to how the systems perform, how on earth can they know whether their designs are any good? How can they improve?

The solution is simple: you just have to get the data out of the meters and start using it, preferably from the very first day the heat is turned on, long before commissioning and handover. The data should be used to verify that the quantifiable performance targets laid out in the spec have in fact been achieved. And all this can be done from a desk, without an engineer travelling to site!

Never mind ESCOs. Who is better placed to ensure that performance is measured and data is used to verify results than the M&E engineer, the client’s trusted advisor? Who is better placed to ensure the client got what they asked for than the good engineers at Fordhams themselves?

But instead of taking steps to measure and improve outcomes, it appears that Bill would rather throw his hands up in despair.

As Gale Snoats wisely said, I’d rather light a candle than curse your darkness. So to finish on a constructive note, here are some recommendations for any M&E engineer working on heat network projects:

• Put clear and measurable performance targets in the spec. Efficiency figures don’t make good targets. Instead use targets like bypass flow rates, flow temps and deltaT. Make sure bidding contractors know exactly what’s expected of them.
• Draw up the commissioning plan at spec stage based on your performance targets and make sure the winning contractor knows they’ll be held to it. Miss the targets? No practical completion til it’s put right.
• Make sure heat meters are installed and commissioned with a working internet connection as early in the project as possible. These meters are the foundation of your measuring system and the ADSL means you can spot problems from your desk.
• Don’t accept commissioning certificates at face value. Verify performance using system data.
• Use the data to improve your next design. Was your last network oversized? Might you have saved the client money on pipes and plant? Did you really need those bypass valves that caused such trouble? Maybe wet towel rails weren’t such a good idea. Etc.