New Eco Housing, Sudbourne Park, Suffolk

SUSTAINABILITY APPRAISAL
The eco houses at Sudbourne Park reflect the horticultural heritage of the site and make varying references
to the use of the sun by the greenhouses for growth and generating energy. The units have
been conceived to be highly energy efficient, and even capable of generating their own electrictiy
and hot water.
Energy
Our design approach to minimise energy use and carbon emissions has been one of the key factors
driving the design. By harnessing environmental conditions through the control of building orientation,
fabric and form and also with the use of efficient controls and micro energy generation, we aim
to achieve a highly sustainable prototype for housing within the setting of a ‘Walled Garden’.
By utilising passive measures, we will minimise the building energy requirements by using inherent
attributes of the building to avoid or minimise the need for mechanical cooling or heating.
An efficient M&E system will minimise plant energy use by selecting the most appropriate engineering
systems and optimising sytem performance. We will maximise the use of on-site renewable
energy technologies where appropriate.
The building will be of a hybrid light/heavyweight construction, providing ample thermal mass to
provide a passive buffer against changing internal temperatures. In addition, it will be insulated in
excess of building regulations requirements and be well sealed against infiltration, minimising the
need for mechanical heating and cooling. For improved thermal performance the minimum U-values
for this building will be enhanced as follows:
Building Element U-Value (W/m2K)
Roof 0.20
Walls 0.25
Floors 0.20
Windows and Doors 1.6
Roof lights 1.8
A whole-house heat recovery ventilation system will be provided. This will be controlled on the basis
of air quality and temperature to maintain a comfortable internal environment. To avoid wasting
energy the system will be zoned, only providing heating and cooling where required.
The building has its major axis running east west, taking full advantage of natural lighting to the
normally occupied rooms of the house. The South & West facing glazing will be specifically designed
to minimise the possibility of undesirable solar gains overheating the space in the Summer months.
The axis of orientation means that there are large areas of minimally pitched east/west facing roof
available for solar collector.
Overall control of the ventilation, heating, cooling and lighting will be by a simple Building and
Energy Management System (BEMS). All systems will be zoned and will operate only when required
with additional timer control to prevent systems being left on unnecessarily.
By the above means, the need for heating and cooling will be minimised by adopting sensible pas
sive measures but where there is demand for either, the loads will be met by a closed loop ground
source heat pump system which is less CO2 intensive than either a gas fired condensing boiler for
heat or an air source heat pump is for heating or cooling. Operating the heat pump during the Summer
to meet any water heating demand will also provide the opportunity of ‘’free’’ cooling to the
dwelling areas using the heat pump’s cooled water discharge.
Building Integrated Solar collectors will be provided in the roofs. The intention is to use as much of
the glass roof area as is economically possible for photovoltaic and solar heating panels to maximise
generation capacity and revenue. An array of this size will be able to generate peak power output in
excess of the demand of the house. Building integrated rather than ‘bolt-on’ PV’s have been selected
to minimise visual impact and create the aesthetic of a traditional slated roof in so far as this is possible.
The combined effect of the passive energy reduction measures, the heat recovery ventilation, the
ground source heat pump and the photovoltaic installation will be to reduce energy consumption
by 62% and carbon emissions by 75% when compared to the same house with conventional design
built to the 2006 Building Regulations standards.
The proposed renewable and sustainable energy technologies have been selected following thorough
analysis on the basis of environmental and financial viability.
It is not anticipated that a full assessment and certification against recognised environmental benchmarking
tools such as BREEAM or Code for Sustainable Homes will be carried out for this project. In
broad terms, the energy consumption reduction measures and generation technologies proposed
for High Meadows would contribute to enabling it to achieve CfSH Code 4 status and with some
further development, Code 5 would be achievable.
Materials
Maximum use is being made of reclaimed materials or recycled materials (such as aggregates) for
construction.
Good quality robust materials with a long design life will be specified for the building. All materials
will be specified to avoid potentially harmful off gassing. The building procurement will ensure that
both the character and origin of the material production methods has been considered and only
responsible and appropriate materials are selected.
Plastics with necessarily harmful production or disposal processes such as uPVC will be avoided
where possible. The secondary aggregates will be used where possible in the structure.
Insulation will be specified with a Global Warming Potential less than 5. The material interface of the
building with the local environment will be enhanced by using vernacular building materials and
design themes.
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