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Hadlow College

Location: Hadlow, Kent

Client: Hadlow College

The Rural Regeneration Centre in Hadlow, is the first certified PassivHaus educational building in the UK. James Anwyl designed and built the Rural Regeneration Centre for Hadlow College, in Kent, one of the top three agricultural colleges in the UK. James is the founding partner at Eurobuild, a company specialising in PassivHaus architecture and construction.

Eurobuild inherited the project from another architectural practice that failed to get planning approval for an iconic sustainable building. Part-funded by SEEDA, a regional development agency, the building was intended as a new teaching facility for the agricultural students and occasional local community use.

On discussion with the Kent planning department, Eurobuild changed the location of the new build, which was originally destined for a green field to the south of the current location. Instead, the planners approved Eurobuild’s intention to use the footprint (and some walls!) from a number of redundant cow sheds on the College’s fully operational dairy farm. Over 95% of the original shed structure was retained on site and a significant proportion was screened and used for non-structural backfill.

During feasibility phase, James established the adjacencies and set out the functional building user flows. The main purpose of the building is to enable seminar-based teaching, with a staff office and meeting space alongside a significant exhibition area used to display the College’s expansive land-based study programmes. One of the spaces required by the College was a semi outside space called the ‘Wet Working Area’. This evolved by preserving the brick and blockwork at the NE corner of the calf shed. The original walls are concealed behind a continuation of the larch cladding. A sliding window from the main seminar room allows students to watch machinery and livestock demonstrations as part of their studies. The farm now benefits from a store and both the store the ‘Wet Working Area’ have large electric roller shutters for access.

Constructed of super-insulated closed panels, the structure was planned using BIM (ArchiCAD) and assembled in just three days. The structure was airtight to a very high standard of 0.34 h-1 in under 10 days overall. Prefabrication led to a high quality finish with significant time savings.

A monitoring system has been installed to track the energy consumption of the building over the next two years and beyond for Eurobuild to learn from the ‘as built’ building performance in relation to weather and usage patterns. The ICT display, ventilation unit and heat pump are monitored individually, in addition to a number of lighting and power circuits. The students and staff can see the results displayed on a very visible monitor in the exhibition area and via the online Building User Guide.

The building employs a number of sustainable technologies including a super efficient mechanical ventilation with heat recovery from Drexel & Weiss; triple glazed windows; and a ground source heat pump for heating & cooling. The sanitary rooms all have waterless urinals, low flush toilets, timed water-saver taps and moderated flow showers. Low energy T5 lighting is used throughout and was carefully planned using DiaLux software.

Natural slate laid on the screed gives a depth of 70mm, whilst the medium density concrete block walls increase thermal mass and absorb the solar gain from the large south facade. Cooling is governed primarily by the ground source heat exchanger in the ventilation unit and backed up by the heat pump and underfloor pipework. In addition, the seminar room windows are time and temperature operated to enable free cooling at night. Individual window pergolas and a colonnade across the south façade prevent overheating in summer — all solar modeled in 3D ArchiCAD, checked with TAS software and backed up by the PHPP analysis.

All the timber used in the project was derived from FSC sources or from sustainably managed forests in Austria and apart from two 1m lengths of steel section (100 x 50) there is no metal in the superstructure. This was a conscious decision in planning with respect to life cycle and embodied energy. As a result of the careful planning, it seems likely from Pre-Assessment that the building might achieve BREEAM ‘Excellent’ rating as well as already achieving PassivHaus certification.