HEATING | LOW-ENERGY GREENHOUSES Were using the outfall from the Anglian Water recycling centres the clean water discharge that goes to the river The two sites use more than ve times as much glass as The Shard Concept Neil Lawson is ESBs head of renewable heat development (and a non-executive director of energy consultant Low Carbon Farming). He has been involved in the project since its inception three years ago, when Oasthouse Ventures began looking into large-scale sustainable greenhouse sites. The original concept was for a low carbon centre with ground source, using waste heat from a local water recycling plant without the need for CHP, Lawson says. But as we moved along, we discovered how much CO2 the plants required. The ground-source heat pumps (GSHPs) deliver the primary heat capacity required for the greenhouses, while the gas-powered CHP will produce the CO2, Lawson says. We realised it was cheaper to use gasfired CHPs to produce CO2 on site than it was to bring bottled gas in. Sized for CO2 production, the capacity of the CHP units are 3 x 1.2MWe for the Norwich site and 2 x 1.2MWe for Bury St Edmunds. In an environment where maintaining heating levels is critical for crop production, emergency backup is provided in the form of a generator, to provide basic power for the greenhouse and heating system circulation pumps, and gas-fired boilers in case of power failure. Lawson, who also led the project to install GSHPs to the recent V&A Dundee scheme (see Playing to the gallery, CIBSE Journal, January 2019), was behind the concept of using waste heat from a water treatment works. One of the fundamental requirements for the project was, therefore, to find suitable farmland in proximity to such facilities with sufficient outflow capacity. The Norwich and Bury St Edmunds sites met these criteria, and ticked other boxes such as being situated on flat, non-flood plain land with access to roads and local labour. Its not just a water heater. Its exceptional quality, reliability & efficiency. 15 Meet the new Multipoint Eco. Energy saving smart thermostatic control New digital display Legionella control system Find out more Call 01603 420220 Email specifier@heatraesadia.com Visit heatraesadia.com DEPT_375219_HeatraeSadia_MultipointEco_HalfHoriz_CIBSE_Oct19.indd 1 09/10/2019 09:54 52 November 2019 www.cibsejournal.com CIBSE Nov19 pp51-54 Heating Tomatoes.indd 52 25/10/2019 15:30