Oxford Radcliffe hospital is low-carbon innovation project of the year

Designed to use a third less energy than the target for a conventional new-build hospital is the new specialist Cancer Care Centre for Oxford Radcliffe Hospitals NHS Trust The new specialist Cancer Care Centre for Oxford Radcliffe Hospitals NHS Trust is designed to be the UK’s most energy-efficient hospital to date following the adoption of a sustainable low-energy solution completed by Halcrow Yolles. The £120 million project will add 35 000 m2 of space to the existing facilities. At the outset, the project was conceived as a sustainable low-energy building with reduced carbon emissions, pollution and water use. The key to low energy use is an array of geothermal boreholes serving heat pumps to provide heating and cooling. This array is around 10 times larger than anything in the UK to date. There will be 250 boreholes, each 123 m deep, and eight heat pumps providing 3.1 MW of heating and cooling. The building is also designed to incorporate natural ventilation wherever possible to reduce the need for mechanical ventilation and room cooling. The estimated energy consumption of 36.8 GJ/100 m3 is significantly lower than the target for a conventional new-build hospital of 55 GJ/100 m3. Indeed, the project has achieved an ‘excellent’ score of 71.59 using the NHS Environmental Assessment Tool (NEAT). Solar gains through the highly glazed facades are limited by brise-soleil. There is fixed solar shading on the South and West elevations to minimise overheating, yet balanced to allow maximum use of daylight. A rainwater harvesting system serving every lavatory on the development and the irrigation system considerably reduce the use of mains water. A major role in the development of the design was the early integration of the IES thermal simulation suite. At preferred bidder stage, the whole hospital was modelled in one go. At detailed design stage, the hospital was modelled room by room, with correct constructions, patient and staff occupancy, medical equipment, small power and lighting loads. IES software was used to determine bulk airflow through naturally ventilated rooms and to predict peak summer temperatures in them. IES software was also used to predict heat and coolth taken from the ground and added to it by the close-loop ground-source borehole array as the designers of the boreholes required hourly figures over the course of a typical year to economically size the array.