An internationally-renowned centre for land-based courses, Pershore College near Evesham is part of the Warwickshire College Group and offers specialist facilities for horticultural study and research.
The latest development on campus, a £5.8m scheme designed by Hitchman Stone Partnership and delivered by main contractor Deeley Construction, combines teaching areas, office space and a new library with a stunning ‘Collections House’, which forms both the building’s impressive entrance lobby and a study and research area for cultivating plants.
Part of the college’s remit is to protect rare and endangered plant species and this environmental focus was central to the development plans, resulting in a challenging brief for Greenways as the building services consultant.
The vast amount of glass involved in the building and the need for a ventilation system designed to nurture plants rather than to save energy created complexities for the services design beyond most college projects. However, the result has been a BREEAM ‘Very Good’ building which meets the needs of both students and plants while offering the college reduced operational costs and an environmental performance aligned to its conservation ethos.
Research & Modelling
The Collections House is effectively a giant greenhouse which spans the entire north elevation of the new facility and extensive curtain walling has also been used for the office and teaching areas to ‘bring the outdoors in’.
While entrance to the main building is through the Collections House, it was clear to the Greenways team that Part L compliance for the main building area would depend on separating the two sections in terms of building controls and this was successfully achieved thanks to close cooperation with local building control officers.
The next challenge for Greenways was to understand the lighting, heating and ventilation requirements for the Collections House to ensure that the growing environment could be tailored to meet the needs of delicate plant life. The building services team worked with the staff at Pershore and horticultural experts at RHS Garden Wisley to calculate the impact of daylight on the north facing building and used climate data to model projected heat gain and heat loss. The modelling process indicated that the Collections House would receive more sunlight than previously thought, which informed the services concept.
Heating & Ventilation
The ventilation strategy was to treat the main teaching block and the Collections House as two distinct buildings. Individual weather stations were designed in, incorporating temperature, CO2 and rain sensors, and these communicate with a separate building management system (BMS) for each section of the building, with integrated communication between the two.
Both parts of the building have been designed with an entirely natural ventilation system with some automated window opening and chimney dampers linked to the weather stations, along with manual opening. The windows of the Collections House will be opened every morning to blast the plants with cool air to aid growth.
The differing needs of the two parts of the building led Greenways to design a complex heating system with nine zones to maximise both comfort and energy efficiency. The Collections House, where the heating is designed to provide optimum conditions for the plants rather than the students, has its own zone, with additional zones for the offices, the library, the stem teaching area and for every group of three classrooms.
All heating is provided by efficient gas boilers in the campus’ central plant room and the building services design incorporated a new pair of heating pipes for the new facility, feeding a radiator-based heating system.
Lighting & Irrigation
The daylight calculations were also critical to the lighting design for both areas of the building. In the Collections House task lighting has been incorporated at low level where students will care for plants, with feature lighting incorporated into the scheme to highlight key specimens and scene setting functionality.
At high level in the Collections House and throughout the teaching and office areas, the lighting specification is entirely LED to provide a light quality close to natural daylight and aid energy efficiency.
The sophisticated lighting control system is also central to lighting efficiency, with daylight dimming linked to sensors and absence detection throughout. Most individual fittings in the building are fully addressable with their own PIR sensor, enabling lighting usage to reflect building occupancy at all times, preventing waste.
The other significant services challenge for the Collections House was irrigation. The facility includes a ‘living’ wall, with plants grown along the full length of the vertical wall for the students to maintain.
Greenways designed a rainwater harvesting system on the roof to feed the irrigation system for this feature and contribute to the irrigation requirements of the entire Collections House, reducing the need to use potable water.
Attractive & Eco
Like any college building, the new facility at Pershore has all the mechanical and electrical services that staff and students would expect, including Cat 6 data capabilities and WiFi throughout, a fully-addressable fire alarm and intruder alarm system linked to the BMS and access control for secure areas.
What sets this building apart is the way in which specialist facilities, an architecturally attractive building and an environmentally progressive learning environment have been combined in a single facility, driving down carbon emissions while improving the student experience.