Page 117 - Rural Housing Association Design Guide
P. 117
Design guide for social housing in rural Northern Ireland Creating rural places: Designing appropriate buildings Energy use and renewable technologies The Northern Ireland Energy market is planning to move from 10% of electricity generated from renewable sources in 2010 to around 40% in 2020. The Energy mix is also expected to move to a mix of natural gas, wind and photovoltaic panels. The cost of electricity and gas is projected to rise by about 30% and 20% respectively in real terms by 2020. Dwellings should be designed to allow for the future installation of renewable technologies as they become more cost effective and allow dwellings to reduce their carbon footprint and minimise the impact of future fuel price rises. 1 HEAT PUMP 3 Air to Water Heat Pumps are expected to become the primary heating source for dwellings as costs fall, efficiencies improve and grid electricity becomes decarbonised. Dwellings should allow for the future conversion to heating systems that can utilise ‘free’ electricity from PV systems through the use of technologies such as heat pumps, etc. Heat pumps operate more efficiently when running at lower temperatures and therefore require larger radiators than fossil fuel systems like gas or oil. With a highly insulated fabric with high thermal mass, the pump can heat the house during the day and the heat will be retained into the evening when the occupants often return. 2 SOLAR HOT WATER Solar Thermal Systems provide around 20% of hot water in the winter months and can provide all the hot water supply in the summer months. 2 A Renewable Heat Incentive Scheme is expected soon and will improve the long paybacks for technologies such as solar thermal panels. 3 PHOTOVOLTAIC PANELS These are now a cost effective renewable technology using subsidies from the NIROC scheme with paybacks within 7 to 10 years depending on the system, its cost, specification, size and orientation. By 2020, as costs are expected to continue to fall, PV systems should be cost effective 1 without subsidy. For an intermittently occupied dwelling, Peak Electrical Demands are generally in the early morning and in the evening, whereas Peak Electrical Supply is at midday. Therefore only 40-50% of the output of PV Systems supplies electricity to the dwelling with the remainder exported to the grid. Increasing the demand for electricity around midday by timing more appliances to run at this time or by converting the electricity generated to heat through an immersion heater element will lead to a more cost effective use of the technology. A dwelling at the notional scheme at Attical, Co.Down, demonstrating the use of appropriate renewable technolo- gies in new-build rural social housing. 116 117
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