BedZED

BedZED stands for Beddington Zero Energy Development; it is constructed on an old disused sewage works in Hackbridge in the London borough of Sutton. BedZED was opened on 8^th June 2002 BedZED consists of 78 homes, 1500m² of Office space, a healthy, living centre, a Café and a childcare facility.

Figure 1: A snapshot of the BedZED development.

Aim

BedZED was designed by the architect Bill Dunster as a demonstration project in how CO₂ emissions can be reduced from the housing sector. Based on predictions from the publication UK Energy and the Environment (Cambridge Econometrics) a 13% rise in household CO₂ is predicted from 1990 levels to 2010 whereas CO₂ emissions are on the decrease in the Power Generation, Manufacturing industry and commerce in on track to meet government targets.

Design Philosophy

BedZED’s design philosophy is that the development will produce as much energy on site from renewable sources as it will consume, in other words a Zero Fossil Fuel Energy Development that will not contribute to global CO₂ emissions.

Incorporated Technologies

BedZED designers have utilized some renewable energy and passive technologies to move towards achieving their aim. Buildings are constructed using Thermal Mass Materials, what these materials do is to store heat when temperature is high and to discharge the heat at cooler times. Insulation is an important factor in modern Energy Efficient building design. BedZED designers were aware of this and insulated all buildings in 300mm thick insulation.

In the UK the most intense sunlight will fall on the South facing of buildings, in the BedZED development houses are South Facing so they receive maximum Solar Heat gain, this falls under the category of Passive Technologies.

In any building a large proportion of heat gain is provided by the occupants the number of occupants and also their level of physical activity this provides what is known as Latent Heat Gains. Activities such as cooking use of electrical equipment also provide heat gain these provide what is known as Casual Heat Gains. BedZED uses these principles in conjunction with their building construction to reduce space-heating requirements, which usually contributes significantly to building energy demand, to reduce BedZED’s Energy Consumption. Office Buildings which are prone large Latent and casual Gains because of occupancy and equipment levels are North facing in the BedZED development, the logic here is to minimize solar gain to counter this effect and reduce overheating and the need to use mechanical ventilation systems which would consume large amounts of energy.

A simple strategy to reduce Energy demand is to use Energy Efficient appliances within households. In European retail outlets Energy Efficient good are marked with the EU Energy Efficiency Label which allows energy efficiency to be rated on a scale of A to G, A being the most efficient as displayed below in Figure 2. BedZED utilizes this strategy.

Figure 2: EU Energy Efficiency Label.

Electricity and Heat is provided to BedZED using a small-scale wood-fuelled CHP plant, the plant uses reclaimed heat from the electricity generation system is used to heat the developments water. Each house also has domestic water tank, BedZED designers used this to their advantage designing the tanks to double up as a radiator if required. Wood-fuel for the CHP plant is Carbon Neutral and there is a need and focus to use such fuels to reduce CO₂ emissions and other Greenhouse Gas Emissions to in line with Kyoto Protocol agreements. BedZED has also harnessed other efficiency measures such as Heat Exchanging Ventilation and Water Conservation Systems.

Embodied Energy

Measures to reduce the embodied energy produced through the construction of BedZED were taken, embodied energy is the total energy used from the extraction of building materials to the disposal of the materials, one factor in increasing embodied energy is long distance material transportation, as a measure BedZED restricted materials sources to a maximum radius of 35 Miles.

BedZED Performance

A projection of BedZED’s ability to meet its energy demand is detailed below in Table 1.

	Energy production (kWh/Year)	Energy Consumption (kWh/Year)	Building Energy Balance (kWh/Year)
Electricity	682,550	640,028	+42,522
Heat	949,365	882,977	+66,388

Table 1: Predicted Energy Use, OVE Arup and Partners, 1999.

No up to date information confirming or dismissing this projection could be found.

BedZED Discussion

BedZED is an example of the current state of the art in Energy Efficient Building design.