Montgomery Zero Carbon Primary School, Exeter
Project
Montgomery Zero Carbon Primary School, Exeter
Client
Devon County Council
Value
£9m
Start/Completion Date
October 2009 - September 2011
Montgomery is to be the first zero carbon school building built in the St Thomas area of Exeter. Existing buildings on the site are being demolished to make way for a new 420-pupil Zero Carbon School, built to European Passivhaus standards. JPA’s sustainable design consultants and the project design team worked closely with Devon County Council (DCC) on the design for the school in order for it to meet the exacting Passivhaus standards. DCC were very committed to the concept of a zero carbon school and this has been a large contributing factor to achieving this standard with the design.
The building is to achieve “zero carbon in use” all CO2 emissions related to energy consumed within the building are to be offset by energy from a renewable source. Roof mounted solar photo-voltaic panels were deemed the best option for achieving this and due to ‘feed in tariffs’ will provide an ongoing financial benefit to the client once the pay-back period has been achieved.
During the winter the building will be mechanically ventilated using a high efficiency central air handling unit with demand based CO2 and occupancy sensing controls. Heat recovery of approximately 95% will be achieved via a reversing regenerator which, in conjunction with both occupancy gains and the high thermal mass from the pre-cast concrete structure, means that virtually no heating will be required. The design has undergone extensive thermal modelling by both NPS Group and Exeter University to prove this concept. Local electrical heaters have been incorporated in the M&E design to allow for some flexibility in this use (i.e. at the end of a holiday period to bring it up to temperature), but these will be under strict control from the BMS to ensure optimum energy efficiency.
Hot water will be provided by an air source heat pump with central water storage and trace heated distribution. Extensive calculations were also undertaken to establish this as the most efficient method of hot water provision given the predicted usage, comparing the system with various permutations of centralised, distributed and direct water heaters.
During the summer the building is to be predominantly naturally ventilated, utilising large roof lights in the central corridor in conjunction with both manual and automatically opening windows in the classrooms and office areas to enable the through-flow of ventilation.
The project is to be subject to a greatly extended period of commissioning and monitoring – including being the subject of an Exeter University PhD. Commissioning is to follow the BSRIA “Soft Landings” approach (involving the client in the building’s operation before, during and post-construction) to ensure the design intention is fully carried through to the operational stage and the building delivers on the design potential.
The building is to achieve “zero carbon in use” all CO2 emissions related to energy consumed within the building are to be offset by energy from a renewable source. Roof mounted solar photo-voltaic panels were deemed the best option for achieving this and due to ‘feed in tariffs’ will provide an ongoing financial benefit to the client once the pay-back period has been achieved.
During the winter the building will be mechanically ventilated using a high efficiency central air handling unit with demand based CO2 and occupancy sensing controls. Heat recovery of approximately 95% will be achieved via a reversing regenerator which, in conjunction with both occupancy gains and the high thermal mass from the pre-cast concrete structure, means that virtually no heating will be required. The design has undergone extensive thermal modelling by both NPS Group and Exeter University to prove this concept. Local electrical heaters have been incorporated in the M&E design to allow for some flexibility in this use (i.e. at the end of a holiday period to bring it up to temperature), but these will be under strict control from the BMS to ensure optimum energy efficiency.
Hot water will be provided by an air source heat pump with central water storage and trace heated distribution. Extensive calculations were also undertaken to establish this as the most efficient method of hot water provision given the predicted usage, comparing the system with various permutations of centralised, distributed and direct water heaters.
During the summer the building is to be predominantly naturally ventilated, utilising large roof lights in the central corridor in conjunction with both manual and automatically opening windows in the classrooms and office areas to enable the through-flow of ventilation.
The project is to be subject to a greatly extended period of commissioning and monitoring – including being the subject of an Exeter University PhD. Commissioning is to follow the BSRIA “Soft Landings” approach (involving the client in the building’s operation before, during and post-construction) to ensure the design intention is fully carried through to the operational stage and the building delivers on the design potential.