This guide is as a result of BSRIA's research project carried out in collaboration with BRE and the industry partners including Danfoss, Frese, Belimo, SAV UK, Andrew Reid & Partners, Crane Fluid, Herz Valves and Grundfos.
It recognises that the potential for pump energy savings is substantial. Europump (a pan European association of pump manufacturers) estimate that systems could be 30 to 50% more energy efficient by careful consideration of components, design and installation. Indeed our research has shown that a potential energy saving of 82% is achievable between the worst operating constant flow systems and the best designed variable flow systems.
Furthermore, in heating and cooling applications a lack of regard for pump energy may lead to missed energy savings elsewhere. For example, excess flows tend to lower system temperature differentials, thereby reducing the effectiveness of some low energy (or low carbon) heating and cooling sources.
Essentially this guide provides recommendations for building services designers on the design of energy efficient pumping systems. However it will be invaluable to a broader group including manufacturers, contractors and end-users who will benefit from being able to design, install, select and manage more efficient systems.
The recommendations presented in this guide, based on extensive research supported by the BRE and the industry, focus on:
- Pump energy fundamentals
- Pipe sizing
- Pipe layout
- System control issues
- Commissioning issues
In summary, our findings show that a pumping system capable of realising the maximum energy savings will have a number of different properties. Some of these include:
- Having a variable flow system with a pump that varies its speed to match the operating load conditions
- A controlled pump speed so as to maintain pressure constant across the most remote DPCV controlled sub-branches
- Pipes sized as large as possible in order to minimise their resistances
A detailed summary of recommendations can be found within the guide.