Francisco Guerrero Neguillo of Oxford Brookes University, UK submit below his proposal for the ECOHOUSE Student Design Competition 2008. Mr. Neguillo won a joint third prize position.
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SITE
This project addresses the proposed redevelopment of the former RAF airbase at Upper Heyford, Oxfordshire (UK). The site is owned by the North Oxfordshire Consortium, which intends to redevelop the site for mixed use. In 2007 a Planning Application was submitted to Cherwell District Council for the development of 1000 dwellings and creation of 1500 jobs.
This project provides an evaluation of the Bioregional context of the site and sets out broad proposals for an alternative sustainable development comprising 1000 houses and creating 1500 jobs based on the Bioregional approach. The aim is to create a framework for development of a sustainable community which minimises carbon emissions and ecological footprint, provides for a healthy and fulfilling quality of life and builds a strong community.
In the UK, for a “standard” house (and life style) built to the 2002 Building Regulations, 40% of the ecological footprint is attributable to transport, food and distribution. Therefore, to provide for a sustainable community there is a need to promote low carbon lifestyles and activities through design of the buildings, community and its relationship with the surrounding region or Bioregion. The Bioregion is the area within which most of the interaction between the community and surrounding area occurs.
Maximising interaction with the Bioregion and minimising the size of the Bioregion closes the loop and minimises energy use (especially for transportation) and waste.
RESOURCES
A- Water
The site is located on the Great Oolite major aquifer which is used in the area for water supply by a number of farms, the groundwater is generally at a depth of 10-15m below ground surface at the site and water quality is generally good
Groundwater supply boreholes are proposed in the main CHP compound where there will also be a water treatment plant for disinfection, adjacent to the fish farm and in the north western part of the site to supply the brewery and other industries in this area.
B- Energy
Presently Upper Heyford is being provided electricity by Southern Electric and Gas by British Gas. The overall aim of the development is to minimise carbon emissions (zero carbon) and minimize the ecological footprint of the site. This leads to a hierarchy of design principles as follows:
- reduce the energy demand by creating energy efficiency buildings and businesses;
- reduce the energy use in transport by creating an environment where living without cars is possible and public transport is convenient;
- generate energy using renewable sources within the bioregion;
- generate energy within the footprint of the site where possible;
- make sure that energy, if utilised from the national grid is from a renewable tariff
On the site, three wind turbines of 40m diameter each are proposed, generating 600kW each, giving a total of 1800kW. However, since wind turbines completely depend on an unreliable source like the wind for power generation, a back-up gas powered CHP has also been provided for in the northern part of the site.
A CHP is located in the southern part of the site, in close proximity to the new proposed community. It is multi-fuel, fired either by wood pellets from the Woodland Coppice on site or by straw from nearby farms. The CHP provides 400kWe of power supplying electricity and heat to the 1000 houses and to the retail, offices and public spaces in the area.
C- Waste
The proposed new development aims to reuse and recycle a large proportion of the waste produced on site in the following way:
D- Sewage
Reed Beds and the Living Machine has been proposed for the new development of 1000 houses The domestic population for the new community is estimated between 2500 and 3000 people giving rise to a minimum of 54,000 litres of sewage per day [Pollution Prevention Guidelines, SEPA]
A proposal has been made to divert recycled grey water, a considerable amount coming from a small settlement of 1000 households itself as per the figures above, from the plant to the Woodland Coppice to provide enough water to sustain a three year coppice (Willow) on this otherwise dry site and adequately fuel the multi-fuel CHP’s.
E- Domestic Waste
Segregation of waste into recyclable (glass, plastic, paper and metal) and bio-degradable waste (kitchen and garden waste) has been included in the design concept. Recyclable waste could be easily transported to the recycling centres in the region. An Anaerobic Digester has been provided close to the CHP in the south of the site for making the best use of bio-degradable waste.
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“GROW” RESIDENTIAL DEVELOPMENT & ITS COMMUNITY
This projects tries to combine and integrate ADAPTABILITY & NATURE.
1. ADAPTABILITY because it is a moment of quick changes in our society ( We encounter different kind of population and different needs as well as demands.
2. NATURE because people like living in Natural Environments. They like going outside and enjoying the nature and their environment. I wanted to give them “THE FEELING OF LIVING IN NATURE“.
Also, I wanted to deliver a ENERGY EFFICIENT BUILDING, and to do so I based my design under the criteria of SUSTAINABITY AND PREFABRICATION —> which will generate a HIGH QUALITY building.
Then, I came across with the IDEA of a building that can GROW.
So, how can the building grow? Some of the guideline might be as follow: In the case of AFFORDABLE Houses the government will provide the TRUNKS. For example, “Planting trunks” as part of the URBAN DEVELOPMENT (as an extension of the roads), and people would buy their prefabricated PODS and PLUG-IT to the building.
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SUN STRATEGY: PASSIVE SOLAR & DAYLIGHT DESIGN
All pods are facing south to maximise the solar gains in the summer.
There are 3 columns of Pods. Columns A and C are stagered so that they can better follow the Sun Path to allow the most sunlight to penetrate to the interior of the building.
As illustrated on the Sun Angle Diagram, we will try to avoid the solar gains in the summer (angle between 45º - 65º) to control the overheating. We will place each pod in section in a position in which they can benefit the most from the middle season solar gains (Angle between 20º - 45º). As shown on section 1-1 the North placed Pods are able to enjoy the sunlight benefits as much as the South row.
Also, in plan the design of the prefabricated Pods envelope helps to collect the maximum sunlight for the back row of Pods following the sun path as illustrated on the typical floor plan.
To protect the Pods form the high temperatures in summer the building is design to provoke an air flow of fresh air raising through the interior of it (see summer air flow diagram).
SUSTAINABLE FEATURES (Aiming for CSH - LEVEL 6 (however further study would be required):
1. ENERGY (Part L < 100%):
-ZERO CARBON TECHNOLOGIES (For heating, electricity & hot water):
a)BIOMASS CHP DISTRICT SYSTEM (FOR 1000 HOMES - 11.200.000kWh):
ELECTRICAL OUTPUT: 490kWe
HEAT OUTPUT: 678kWt
THE CHP ENGINE HAS BEEN SIZED TO MEET THE DEVELOPMENT HEAT DEMAND
b)THE EXTRA ELECTRICITY DEMAND WILL BE SUPPLIED BY WIND TURBINES ON SITE.
CHP WILL REDUCE BY 18% THE DEVELOPMENT ENERGY DEMAND AND BY 11% THE DEVELOPMENT CO2 EMISSIONS. THE PAYBACK PERIOD IS 1.8 YEARS (refer to Bioregional CHP report)
-BUILDING LOSSES (FABRIC AIR TIGHTNESS) - IMPROVED THROUGH PREFABRICATED CONSTRUCTION METHODS (Heat loss parameter < 0.8W/m2K)
U values (W/m2K):
(PassivHaus targets to U-value that does not go above 0.15 W/m2K)
-Walls = 0.13 (Wood frame Strawbale) & 0.14 (Precast Concrete + foamglass external insulation)
-Roofs = 0.09 (Wood frame Strawbale + green roof) & 0.14 (Precast Concrete + foamglass external insulation)
-Floors = 0.11 (Timber flooring +Wood frame Strabale) +0.12 (Soil + Precast Concrete + foamglass external insulation)
-Windows & Doors = 0.70 (2 Low-e pane argon infill Triple glazing - hardwood frame)
-DEDICATED ENERGY EFFICIENT LIGHTS
-ENERGY EFFICIENT APPLIANCES
2. WATER (< 80 litres/person/day):
a) REDUCTION OF INTERNAL POTABLE WATER:
-DUAL FLUSH WC
-AERATED TAPS
-SHOWER FLOW RESTRICTORS
-RAINWATER HARVESTING SYSTEM:
FOR FLUSHING
FOR WASHING MACHINE
-GRAY WATER RECYCLING: IT WILL BE TAKEN TO THE WETLANDS TO BE NATURALLY FILTERED AND PUMPED BACK UP WHEN REQUIRED (using renewable electricity for the pumps).
b) REDUCTION OF EXTERNAL POTABLE WATER:
-RAINWATER HARVESTING SYSTEM
FOR WATERING THE PLANTS
3. MATERIALS:
a) REDUCTION OF THE ENVIRONMENTAL IMPACT OF MATERIALS:
-USE OF MATERIALS GRADED AS “A” or “A+” ON THE GREEN GUIDE TO SPECIFICATION.
b) RESPONSIBLE SOURCING OF MATERIALS (WITHIN THE BIOREGION)
-MATERIALS WITH “EMAS” CERTIFICATION (ECO-MANAGMENT & AUDIT SCHEME) -key processes and supply chain
-”FSC” CERTIFIED WOOD (CoC certification -chain of custody)
4. WATER RUN OFF:
-THERE IS NO REDUCTION OF SURFACE WATER RUN OFF - WETLANDS IS AN ATTENUATION METHOD - AND RAINWATER HARVESTING SYSTEM - GREEN ROOF
5. WASTE:
a) PROVISION OF STORAGE SPACE FOR HOUSEHOLD & RECYCLING WASTE
-INTERNAL STORAGE BINS FOR RECYCLABLE WASTE
-EXTERNAL STORAGE SPACE FOR BINS PLUS A LOCAL AUTHORITY SCHEME
b) IMPLEMENTATION OF A SITE WASTE MANAGEMENT PLAN INCLUDING PROCEDURE TO MINIMISE WASTE ON SITE, AS WELL AS TO SORT, REUSE & RECYCLE CONSTRUCTION WASTE
c) INDIVIDUAL HOME COMPOSTING CONTAINERS (or LOCAL AUTHORITY KITCHEN WASTE COLLECTION SCHEME)
6. POLLUTION:
a) NO USE OF GWP(GLOBAL WARMING POTENTIAL) INSULANTS
b) DRY NOx LEVELS KEPT TO <40 mg/kWh per Dwelling (HEATING SYSTEM)
7. HEALTH & WELLBEING:
-DAYLIGHT
a) ALL LIVING SPACES HAVE A DAYLIGHT FACTOR > 2%
b) THERE IS A VIEW OF THE SKY FROM ALL LIVING SPACES
-INSULATION
AIRBONE SOUND & IMPACT INSULATION ARE IMPROVED BY 8dB OVER THE APPROVED DOCUMENT E (2003).
-A PRIVATE OUTDOOR SPACE IS PROVIDED
-LIFETIME HOMES COMPLIANT
7. MANAGEMENT:
-HOME USER GUIDE PROVIDED
-CONSIDERATE CONSTRUCTION SCHEME BEYOND BEST PRACTICE WILL BE IMPLEMENTED (USE OF PREFABRICATED UNIT)
8. ECOLOGY
-NO IMPACT ON THE ECOLOGICAL VALUE OF THE SITE (BUT ENHANCEMENT OF IT)
-REDUCED BUILDING FOOTPRINT
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SUMMARY OF STRATEGIES
1. MATERIALS:
-WOOD FRAMED STRAWBALE
-GGBS SUSTAINABLE CONCRETE
-RECLAIMED WOOD FOR PLANTS’ SUPPORT
-SPECTRALLY SECTIVE DOUBLE SILVER COATED ARGON-INFILLED TRIPLE GLAZING
2. CONSTRUCTION SYSTEMS:
WATER HARVESTING SYSTEM
THERMALLY BROKEN EXTERNAL STRUCTURES
SUPERINSULATION TO REDUCE THE HEATING DEMAND
PASIVE SOLAR DESIGN
DAYLIGHT ENVELOPE
GREEN ROOF
3. WETLANDS: GRAY WATER RECYCLING
4. CROSS VENTILATION - NIGHT COOLING IN SUMMER
5. SUSTAINABLE CONCRETE THERMAL MASS - AS A HEAT STORAGE
6. PREFABRICATION:
-METHOD OF HIGH QUALITY GENERATION
-REDUCTION OF CONSTRUCTION WASTE AND THE TIME OF CONSTRUCTION
7. BIOMASS CHP DISTRICT HEATING - ZERO CARBON TECHNOLOGY
8. HOUSEHOLD AND RECYCLING WASTE STRATEGY - COMPOSTING
-STRUCTURAL PRINCIPAL:
CONSTRAING THE THREE DEGREE OF FREEDOM ON THE STRUCTURE (IT FOLLOWS THE ANALOGY OF A TREE)
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IES MODEL
DESIGN PROCESS FOLLOWED (120m2):
STUDIED STEPS :
1. ALL STRAWBALE + SHADDING DEVICE:
-11.600 kWh/year & Maximum Temp. in the building (BUFFER ZONE) = 26.5ºC
2. EXTERNALLY INSULATED CONCRETE + STRAWBALE + NO SHADDING DEVICE:
-9.400 kWh/year & Maximum Temp. in the building (BUFFER ZONE) = 31ºC
3. EXTERNALLY INSULATED CONCRETE + STRAWBALE + 0.5m LONG SHADDING DEVICE:
-9.900 kWh/year & Maximum Temp. in the building (BUFFER ZONE) = 29ºC
4. EXTERNALLY INSULATED CONCRETE + STRAWBALE + 0.5m LONG SHADDING DEVICE + NO WINDOW OPENING PROFILE THROUGHOUT THE YEAR:
-10.600 kWh/year & Maximum Temp. in the building (BUFFER ZONE) = 31ºC
5. EXTERNALLY INSULATED CONCRETE + STRAWBALE + 0.8m LONG SHADDING DEVICE + WINDOW OPENING PROFILE THROUGHOUT THE YEAR (JUN-JUL-AUG) + TRIPLE GLAZING:
-6.600 kWh/year & Maximum Temp. in the building (BUFFER ZONE) = 25ºC
* WITH THE USE OF THE BIOMASS CHP UNIT THE DEVELOPMENT ENERGY DEMAND WILL REDUCED BY 18% AND THE DEVELOPMENT CO2 EMISSIONS BY 11%
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Contact:
Francisco Guerrero Neguillo - pguerrero23@hotmail.com
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