UK: Trane has provided two heat pump chillers using Honeywell’s low GWP HFO refrigerant R1234ze in a groundbreaking district heating network in Scotland.
The district heating network will supply local public buildings and businesses in Stirling, using a variety of renewable energy sources including wastewater from the Stirling Waste Water Treatment Works.
The £6m project, developed in partnership with Scottish Water Horizons and Stirling Council, with support from the Scottish Government’s Low Carbon Infrastructure Transition Programme (LCITP), has the potential to save up to 381 tonnes of carbon per year.
The technology is the first of its kind in the UK to use sewage and wastewater heat recovery technology alongside a CHP engine to generate heat and electricity in a single, highly efficient process.
The two CITY RTSF units, with a total capacity of 800kW, will extract heat from sewage and wastewater. They are based on inverter-driven screw compressor technology and use stainless steel brazed plate heat exchangers as both the condenser and evaporator. This helps to prevent corrosion at higher heating temperatures and with water that could have different ph levels.
The operating map of the RTSF is very wide and can produce hot heating water at a temperature of 80ºC and yet still be used in cooling systems to produce water at more conventional temperatures of 6ºC, or even low temperature applications of -12ºC.