Heat network at Sønderby – images from linked design guide
When writing a recent post about the low temperature DH network at Lystrup, I contacted the author of the related technical report, Jan Thorsen. In Jan’s response he kindly included a copy of Guidelines for Low-Temperature District Heating (PDF).
This guide is essential reading for designers and operators of DH systems. It shows how DH with flow temperatures of around 55 and return temps of around 25 (also called “fourth generation” or “4GDH”) can be used to serve high efficiency homes as well as buildings on low heat density networks.
At this point you might say, hang on a minute – what are we doing considering 4GDH when we struggle to deliver decent 3rd generation (70/40) networks in the UK? And I’d say you’ve got a point. In fact, I spent a depressingly large chunk of last week trying to help salvage the efficiency of another new network that is horrendously oversized and was probably doomed to low efficiency before it even left the drawing board. So I’m sympathetic with the view that UK engineers need to get our houses in order before moving onto the cutting edge stuff.
But looking ahead to the strategies employed in more advanced, lower temperature systems helps to highlight the design principles that we should be focusing on, even on today’s projects in the UK.
carbon limited 