HIU performance testing will change heat network design

SAV Systems has welcomed the announcement of a new regime for testing heat interface units (HIUs), noting its potential to significantly improve the performance of heat networks.

“Under-performance of heat networks is often down to poorly designed HIUs that are unable to cope with variations in the system and fail to maintain the temperature differentials required for optimum efficiency,” observed SAV Sales Director Jan Hansen. “This new testing regime is more demanding than its predecessor and the adoption of the new test standard by the Building Engineering Services Association will ensure wider compliance,” he added. SAV has supported HIU testing since the introduction of an earlier regime developed by Fairheat with support from the then Department of Energy & Climate Change (DECC). The first round of tests showed that SAV’s Danfoss FlatStation HIUs provided the lowest VWART (Volume Weighted Average Return Temperatures) values of all HIUs tested. SAV will now be submitting FlatStations for testing under the new regime. “We are very focused on the performance of the whole system at both full and part load conditions and FlatStations are optimised to deal with varying system differential pressures and high performance at low, high and dynamic DHW tapping conditions,” Jan Hansen continued. “We are therefore confident that they will exceed the requirements of the new tests. We are also particularly pleased the new regime will conduct tests based on both 70°C and 60°C primary supply temperatures as Danfoss FlatStations are optimised to perform efficiently with the low temperature heat networks of the future.” “Indeed, we would like to see even more rigorous HIU testing, underpinned by penalties for heat networks that don’t perform adequately – such as failing to maintain a Delta T of 30°C. This will encourage a more holistic approach that looks beyond the HIUs to other factors such as correct installation and proper balancing of heat emitters,” he noted. Read more about the impact of HIU performance testing on heat network design in the CIBSE Journal. A more detailed news release is also available on the HVR website.

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