3 Potential Pitfalls in District Heating Design
District heating schemes can provide heating and hot water at a lower cost and in a more efficient way than some traditional systems, but to do this, heat network designers must first navigate their way through a number of potential pitfalls.
Here are three of the oversights we’ve seen made in district heating system design.
1. Oversizing and inappropriate boilers
Heat networks and plant heating sources can be oversized due to a lack of experience and guidance on design best practice, and more often than not, an overcautious approach is taken to allow extra room for unknown elements.
Smaller heat networks also often lack renewable and low carbon energy heat sources which can really deliver on efficiency and reduced energy costs. To tackle this, peak load boilers should only operate when the load can’t be met by these more efficient heat sources and should be selected based on good turndown ratios – to cope with low level demand as well as the peaks.
Inappropriate diversity factors for DHW demand and overcautious delivery temperatures also affect the size, efficiency and cost of a network.
2. Over-reliance on lateral pipework
Where possible, pipe work runs need to be more carefully considered to reduce heat loss to below 10%. Lateral runs tend to suffer the most from poor installation and insulation so it may be worth breaking up a network into multiple vertical runs which are often better installed and insulated. Opting for smaller pipe sizes which have reduced surface areas will also lower heat losses and allow for optimum efficiency.
3. Copying from overseas
European and Scandinavian countries are renowned for their well-performing, efficient district heating schemes. Instead of replicating these successful larger projects though, we should consider typical UK operating conditions and think about the long-term effects of a heat network from day one, particularly for the end user.
The efficiency of a heat network is dependent upon correct design procedures from the outset. Therefore, getting a grasp of the above three considerations will help the UK to be better-equipped in avoiding any potential pitfalls.