HEAT PUMPS | STAR RENEWABLE ENERGY Twin water source heat pumps to be installed at Queens Quay Pearson is passionate fanatical even about the potential for heat pumps to replace burning fossil fuels, such as natural gas, to provide heat the world, says Pearson. He admits there were some elements of the Drammen installation that were a wee bit sticky, but he points out that innovating is not without its challenges and says Star stuck with it and got it right. The ammonia-based heat pumps are now delivering 85% of Drammens near-70GWh of heat each year. Gas is only for top-up on the coldest days. At about the same time as the Drammen heat pump was coming on line, the UK government was talking about the need to decarbonise heat as a consequence of the EUs renewable energy sources directive. Star saw an opportunity to use its experience of Drammen to grow its business. Wed decided that a big part of the business going forward would be in heating as well as cooling, says Pearson. However, biomass and gas combined heat and power (CHP) as well as a reluctance to change left Star frustrated at the slow uptake. So, in 2013, it set up Star Renewable Energy, a new division to focus specifically on big heat pump projects for district heating systems. We understand heat exchangers and compressors and thermodynamics; if there is going to be a trend for heat pumps, then we should be part of that, Pearson says. I now lead that business unit, which is able to draw on all the refrigeration skills we already have at Star, but for a totally different application. Pearson is passionate fanatical even about the potential for heat pumps to replace burning fossil fuels, such as natural gas, to provide heat. Heating is about 50% of the energy consumed in the UK, so we have this challenge of how to do QUEENS QUAY A WATER SOURCE HEAT PUMP ON THE RIVER CLYDE Client: Vital Energi Refrigerant: Ammonia Capacity: 5.2MW Temperature: 80C/60C, then 75C/45C Supported by the Scottish Government Low Carbon Infrastructure Investment Programme Scotlands first major district heating network served by a river-source heat pump is currently being installed under West Dunbartonshire Councils 250m regeneration scheme for the Clydebank area. This residential-led, 23-hectare development, on the site of the former John Brown shipyard, includes the addition of new homes and business premises. The schemes location, on the banks of the river Clyde, made it the perfect application for a water-source heat pump. The 5.2MW heat pump will extract heat from the river and use it to supply the district heating system. The heat pump has been designed to run on an open-loop design, with water abstracted from the river in direct contact with the evaporator heat exchanger. The 15m district heating system will connect to existing buildings in the area, the majority of which are currently heated by gas and generally run at 80C flow/70C return. Initially, the temperature of heating mains will be 80C flow, 60C return. However, to improve the heat pumps efficiency, the temperature of the heating mains will be lowered to 75C/45C over time. New developments are being built with heating systems designed to operate at 75C/45C, while the heating systems in existing buildings will be adapted to enable them to operate effectively at these temperatures. Properties are connected to the district heating network via a heat interface unit. 18 May 2019 www.cibsejournal.com CIBSE May19 pp16-18, 20 Dave Pearson Supp.indd 18 26/04/2019 16:15