Open University, Building 12Walton Hall Campus, Milton Keynes

The imperative was to reduce the performance gap between low-energy simulated design and actual in-use building performance, whilst achieving high degrees of occupant comfort and control.

The Open University’s Estate Department was one of the first UK office buildings to achieve BREEAM Outstanding. It was designed and thermally modelled to ensure it could passively moderate its internal environment. The passive design features include a thermal mass construction, good provision of natural daylight, control of solar gains, natural ventilation and night cooling, stack effect driven air movement and high levels of thermal insulation.

The project was delivered as part of a partnering framework, where the contractor, consultants and client team had visibility of the design, cost and programme to enable collaborative and critical thinking and drive maximum value throughout the design and construction periods.

BREEAM Outstanding

One of the first UK Office buildings to achieve
Passive nighttime summer cooling

Enables mid 20 degree internal temperatures when external daytime temperatures in excess of 30 degrees
Design process

that achieved value where it mattered most across the stakeholder teams.

Ridge was excellent during the briefing process, to challenge us and to set the objectives and expectations for us to meet the project requirements. Ridge’s cross team working and value management processes resulted in excellent value for money and helped to instill an outstanding team ethos across all levels of the design and delivery teams. The building is functioning exceptionally both in winter and summer months and the low-energy, passive design measures are providing excellent levels of comfort for our staff.

Ralph Lachmann
The Open University

Results

The low-energy measures put in place include:

Excellent thermal performance coupled with a high degree of airtightness and exposed thermal mass
Deep glazing reveals and brise solei to help reduce solar gains and cut out angle glare
Passive ventilation strategies, including a forced stack effect through innovative solar chimneys
Planted intensive roof garden for biodiversity and rainwater attenuation
Internal garden courtyards introducing green views and providing useful outdoor space and internal ventilation
Ventilation controlled locally by users opening windows, ventilation louvres and stack effect for night time cooling

The active environmental measures include:

Renewable energy sources generating electricity by photovoltaic panels
Hot water provided from solar thermal roof panels
Ground source heat pumps providing low temperature hot water for underfloor heating