energy projects in mk
Milton Keynes has led the way in low energy housing and other projects designed to raise energy efficiency for almost 40 years. This page looks at some of the early experimental homes designed to cut energy use in the 1970s and 1980s. Architects were attracted to Milton Keynes as a city where it was possible to test innovative ideas for low energy and sustainable homes. Early experiments focused on gaining free energy from the sun - including homes designed to actively capture the sun's warmth to heat water and the rooms inside. These homes also included much higher levels of insulation than were normal in Britain at the time. Although many were in small developments, some tested ideas and set standards that were later adopted acrooss the new city and the UK as a whole.
The Bradville Solar House: Milton Keynes' first active solar house (1972)
The Bradville Solar House was Milton Keynes' first active solar house.
The solar heating system was fitted to a standard terraced rental house built by Milton Keynes Development Corporation (MKDC). The system consisted of 37m2 of aluminium collector on a south facing roof sloping 30° from the horizontal. Since solar heating is mainly required during seasons when the sun is low in the sky, this 30° was a little too shallow for maximum performance. The heated water flowed indirectly through a warm air space heating system and a conventional domestic hot water cylinder.
In order to cope with the unpredictability of sunshine hours, a 4,500 litre water store and a conventional boiler were incorporated. The system was designed to substitute for 50% of annual requirements, but monitoring showed that only 31% was achieved initially. Improvements in panel insulation and draught stripping raised this to 56%, but the resulting payback period of 50-60 years was still high by usual standards.
An improved version could achieve a 20 year payback period; this was still high compared to many of the other projects in Milton Keynes. However, in environmental terms the 56% fuel saving (and the resulting reduction in carbon dioxide emissions) was a major success.
Solar Court (Linford Project): Nine highly insulated homes with three types of heating (1979)
Nine outwardly similar houses were built at Solar Court in 1979/80. The nine houses comprised three groups of three houses, each group having a different heating system. All houses incorporated much more insulation than required by the Building Regulations in force at the time. They were double glazed and had 50mm of insulation in the wall cavities, 100mm in the loft and 25mm under the floor slab.
The three 'Type 3' houses had 40mm2 of roof-mounted copper solar collector which transferred heat to a 2000 litre storage system. This storage system in turn provided energy to a warm air space heating system and to the domestic hot water system. Heat was recovered from waste ventilation air and from waste water, and an auxiliary gas boiler provided for needs in excess of those which could be met by the solar system.
The three 'Type 2' houses had 18.5mm2 of similar solar collectors, and a 6000 litre store. Heat from waste water and ventilation air was recovered, the whole system being integrated by an electric heat pump. Background heating was obtained by passing solar heated water at 15°C through coiled pipes in the floor, and additional heating was obtained by passing higher temperature solar heated water through a warm air system. Again, auxiliary gas boilers were also installed.
The three 'Type 1' houses contained conventional gas warm air heaters and no solar features. They were built as 'controls' for the monitoring project.
In the houses with solar heating systems, problems were initially encountered with freezing and generally with the complexity of the systems. Nevertheless, solar contributions of 62% were eventually achieved.
At the east side of Solar Court, a further development of three houses included integral south-facing conservatories with fans to distribute warmed air throughout the houses, and solar water preheating panels.
Rainbow Housing Cooperative: retrofitting an active solar element to a Victorian home in New Bradwell (1980)
In 1980 a lean-to conservatory was built on the rear (southerly) side of a 19th Century terraced cottage in New Bradwell. The cottage was originally built for railway workers, and at the time of this project was owned by the Rainbow Housing Cooperative. The benefits of the conservatory were fourfold: heat losses from the wall were reduced, air entering the cottage naturally via the conservatory was preheated, normal solar gains occurred by conduction and a fan was installed to force preheated air into the lounge. It is the inclusion of the fan system that makes the system 'hybrid' solar (a combination of active and passive) rather than just passive solar.
Monitoring showed that some 12-15% of heating fuel was saved. Since 10-13% would still have been saved without the fan, it was felt that the cost of that particular element did not justify its installation. Summer overheating was avoided by the use of automatically opening roof vents.
This project is of particular interest because it is one of the few early examples in Milton Keynes of energy measures fitted to a house after it was built.
Summerhayes: Demonstrating low energy homes could be sold to the private sector (1980)
This project, built during 1980/81 at the South-East end of Summerhayes, Great Linford, extended the Pennyland philosophy of carefully aligning homes to face South, but without creating the impression of homes in serried rows. It successfully demonstrated that the concept could apply private sector developer sale housing as well as to public sector rental housing. The eight houses were designed with a very large proportion of the glazing on the south face, and with considerably better insulation than demanded by Building Regulations (the houses had 100mm filled wall cavities, 140mm roof insulation and 25mm floor edge insulation). Dense concrete block was used in the construction of cavity wall inner skins and internal partition walls, to increase thermal storage.
Performance during two winters was monitored intensively, with fuel use, detailed heat flows, window openings/closings and heat loss photographs ('thermo graphic images') all being recorded. It was found that floor heat losses were higher than expected, simply because the nature of such losses was poorly understood at the time. Window 'clutter' (e.g. net curtains) was found to have a significant effect on the solar gains. Due to differences in lifestyle (e.g. desired temperatures), the ratio of highest to lowest fuel was 2:1.
The houses achieved on average a 40% saving in space heating costs, which easily justified the 1% additional construction cost. Solar contributed between 17% and 33% of space heating, and there was no summer overheating. The payback period was just over two years, this figure being considered an excellent return on investment.
Flats and starter homes in Giffard Park (1984)
Thirty six flats and 'starter' houses were built by Giffard Park Housing Cooperative in 1984. The challenge was to achieve a 60% reduction in space heating fuel requirements for no more than an additional £500 in construction costs.
The homes were arranged in four identical terraces with as little over shading as possible, and 75% of the glazing facing south. The internal layouts had lounges, dining rooms and bedrooms also positioned on the south side. The twelve largest houses had small, simple gravity-fed solar panels for preheating the cold supply to the domestic hot water cylinder, and he lounges extended into integral conservatories. Insulation consisted of 75mm in the wall cavities, 25mm under the floor slabs and 140mm in the roofs. First storey floors and all partition walls were constructed with dense concrete to provide thermal storage. Insulated blinds were fitted to some windows.
Capital cost savings were made by installing gas room heaters and reduced-size hot water heaters rather than full central heating; and in practice, a 61% reduction in space heating was achieved.
Superinsulated Houses at Two Mile Ash (1985)
Superinsulated houses are usually defined as houses which have extremely low space heating fuel requirements, achieved not by solar methods or special heating appliances but by heavily insulating the fabric and paying great attention to air tightness and introducing controlled ventilation.
In 1985, four timber-framed superinsulated houses were built at Two Mile Ash. The houses arrived in kit form from the Finnish supplier, with panels up to 10m x 2.4m being delivered fully fitted with insulation, windows, cladding and internal finishes. Construction time was therefore extremely short.
The walls incorporated 185mm of insulation, the floor 100mm and the roof 300mm. All windows were triple glazed, and a heat-reflecting 'low emissivity' coating gave the equivalent effect of quadruple glazing. During construction, much attention was paid to sealing the structure to achieve good air tightness. A mechanical ventilation system with heat recovery was installed to provide the controlled ventilation necessary to avoid condensation in such well sealed houses.
Space heating was from a gas fired 'heatsaver' system (reduced-sized boiler and integral water-based heat store), distributed via the ventilation system.
The houses sold for only 6% more than conventional equivalents, yet monitoring verified an 84% saving in space heating fuel (in other words a near-zero requirement). A two year payback resulted.
The success of these houses was confirmed by the fact that in the early stages of occupation, mere heat leak from the airing cupboard tended to cause overheating of the houses (rectified by improved tank lagging). In addition, the heat given off by lights, electrical appliances, cooking and people was usually enough to keep the houses warm; the heating systems not being needed until prolonged periods of very cold weather occurred.
Please note...
Many of the projects described here were designed to improve the energy performance of private homes. If you wish to view any of the properties described please remember that they remain private, and avoid taking photographs or otherwise intruding on residents' privacy.
