Case Studies 0


The substation in Melksham had two buildings in it which were being heated constantly, this is very bad for the environment and a waste of heat most the time if nobody is in the building.

Rookservices has installed a renewable heating solution which uses waste heat from transformers at the substation. This provides space and hot water heating for the two buildings. The new system, which was designed to help reduce national grids carbon footprint, has been successfully installed in Melksham.

The brick enclosures are designed to reduce noise for surrounding properties that comes from the transformer inside. However, the temperature of the air inside each enclosure is higher than the ambient air because of the heat wastage from the transformers. Water flows through the header pipe to each brick enclosure, where it is warmed sufficiently and returned to the heat pumps, which are located in a dedicated plant room. The heat pump system feeds new wet radiator systems installed in the substation buildings together with hot water.

Combining intelligent system design with high efficiency products, this unique application has enabled Rook Service to install renewable heating where ground source heat pump collectors or air source heat pumps may not be viable. It recovers significant waste heat from the transformers to provide free heating for the substation buildings contributing to National Grid’s overall CSR strategy and commitment to reduce carbon footprint. The system is expected to pay back in less than seven years.

Short Details

  • 2 x 38 kW Vaillaint geotherms GSHPs 78kW GSHP servering 2 buildings
  • Utilised 4 SGTs for source side 4 40kW Dry Air Coolers
  • Brine temperatures recorder from 10 – 20°C
  • Ground loop = 800m of primary and header pipework
  • Used low temperature jaga rads @ 45/38°C
  • Utilised MLCP pipework for the plumbing side from Flo Gas
  • Payback 7 years

Another smaller system at Melksham

  • 1 x 22kW GSHP
  • 1x 40kW Dry air cooler
  • 400m of primary pipework
  • Brine temps of 12-20°C
  • MLCP
  • Jaga strada
  • Payback 4 years