From the outset, the project team was committed to developing an environmentally sustainable scheme to provide good-quality affordable accommodation, both now and well into the future. Consequently, the buildings are well insulated and have been designed to take advantage of passive solar gain and natural light, thereby reducing the demand for mechanical heating and electric lighting respectively. Average CO 2 emissions per dwelling are estimated to have a weighted average of 22kg/m 2/year.
The project team recognised that over the lifetime of the development, the way in which homes are serviced will change dramatically.
The roofscape has therefore been designed to provide favourable orientation for future installation of photovoltaic panels, and dedicated space has been provided within service risers for the associated cabling.
The heating system for the buildings has also been developed with the long-term future in mind. During the consultation process, the residents identified district or community heating as being one of the few features of the estate that they wished to retain. Max Fordham carried out a study to compare the relative benefits of community heating and individual dwelling-based, gas-fired heating systems.
In particular, the study examined the potential for using a CHP unit, which would generate electricity and heat very efficiently for use on site. The study concluded that a community heating system with a CHP unit sized to meet the continuous hot water demand would be more energy efficient, emit less CO 2 and be cheaper to operate and maintain than individual dwelling-based, gas-fired heating systems. (The CHP system is predicted to meet 11 per cent of overall heat load and 12 per cent of the electricity demand. ) However, the capital cost of the community heating system is significantly higher than it would have been if individual dwelling-based systems had been installed. Nevertheless, the client remained committed to the principle of a community heating scheme with CHP, recognising that, if fossil fuel prices continue to rise, then the long-term annual savings associated with CHP are likely to increase.
Ultimately, electricity generated by the CHP unit will be used to power the landlord's services and some dwellings, reducing the need to buy electricity from the grid. While the installed CHP unit is gas-fired, it will be relatively easy to replace it with one powered by an alternative 'greener' fuel as technology and economics allow.
Alasdair Reid, Max Fordham