Earlier this year the London Branch/ Surrey Discussion Centre visited the Natural History Museum in London’s South Kensington.
A small group of members were guests of Vital Energi, the contract energy funders for the site, with the company’s business development manager, Mark Howell, giving a detailed background lecture and conducting the members around the 1.8 MWe tri-generation energy centre that supplements the existing central district heating boilers at the museum. John Crawford, the branch chairman, who was to retire after almost 50 years in engineering not long afterwards (see article in the January 2011 issue of HEJ), said: “For 100 years, from the 1880s, the Natural History Museum’s coal-fired district heating systems had supplied the famous adjacent museums on London’s Exhibition Road, the Victoria & Albert Museum, and the Science Museum, plus The Imperial College. “Then, some 25 years ago, the district heating was upgraded via the installation of four dual-fired Dank water tube boilers to give 42 MW of heat output at 130°C. However, since 2000 the scheme had only served the Natural History Museum and the Victoria and Albert Museum, leading to increased costs for both museums. The need to reduce these was one of the main reasons for proceeding with the Vital Energi installation, along with the benefits of carbon reduction and energy efficiency. “Two of the existing four central boilers were scrapped, and Vital Energi funded their replacement by installing a new combined heat and power (CHP) and absorption chiller plant within the same space.” The £12 million scheme has operated for the past three and a half years, when the Natural History Museum contracted out to Vital Energi the funding, installation, running, and maintenance, of the plant for a 15-year period The equipment comprises a General Electric/Jenbacher gas-fired reciprocating engine/CHP which produces electricity and low grade waste heat at 95/65°C. The heat balance duties are: 1.819 MWe (42.1%); 1.903 MW heat (44%), and 4.318 MW heat input. The waste heat serves two Thermax absorption chillers, each rated at 705 kW, and with a heat input of 1011 kW, with a Coefficient of Performance (COP) of only 0.7. The Natural History Museum now generates in parallel with the national grid, 24 hours a day, instead of the 17 hours originally planned. The Museum does not export electricity, so all the power generated is used to supply base load, which is supplemented by imports from the term electricity supplier, Scottish and Southern. Maximum demand is 4 MW. Only heat is exported to the Victoria & Albert Museum, while the scheme’s tri-generation output is used within the Natural History Museum.
