Photovoltaic Panels:
A description of the Photovoltaic Generator Systems installed on the Alpine Close Development, by Solar Century

The photovoltaic system installed is a 'Grid Connect' system. This means that the PV panels are connected to the National Grid via an inverter without any battery storage.

The photovoltaic modules have been installed onto a purpose built solar upstand to the rear of the roofs, at an angle of 45 degrees.

The output to each dwelling ranges from about 1kW to 1.8kW, depending on the configuration and number of panels per dwelling. The total installed power is 20.4kW.

An array of panels comprise of Astropower 75 Watt modules fitted into a framing system, connected to an inverter in the loft of each dwelling. The inverters convert the direct current power produced by the modules to 240V alternating current as required by domestic equipment. The power is either used within the dwelling or, if more power is produced than is being used, the surplus is exported to the National Grid. The home then becomes a power producer and will be paid at an agreed rate by the electricity supplier.

The systems will provide between 30% and 90% of the electrical needs of the dwellings depending on the system size and energy requirements of the home user.

The performance of each system in monitored with data being recorded by a data logging unit. The data logger allows remote access via a telephone line to each inverter. This allows remote sensing of the systems for performance and fault conditions.

The development also has a set of reference sensors which provide temperature and irradiance data for comparison and analysis of system performance.

Solar Century have produced a case study on this project, which can be downloaded from their web site here.

Accessible Ducts:
All dwellings have a vertical service duct, containing the main soil stacks, ventilation ducts, hot-water cylinders, wiring etc. Centralising these essential services reduces unnecessary pipe-runs and contains all services in one easily identifiable and accessible area.

For example, removable skirtings and cornice level panels give access to wiring and pipes running around the house. Should a tenant or landlord wish to upgrade their facilities, ie: new data cabling, house hi-fi system or some new technology just around the corner, these can be installed without leaving exposed wires around the home and with minimal disruption to finishes. The panels can be removed, new cabling installed and the panels replaced. No tacking cables around the corners of rooms, no drilling walls or removing plasterboard etc.

Each dwelling also has service routes to allow total accessibility to pipes and cables, facilitating the easy repair or upgrading of infrastructure at later dates without damaging fabric or finishes.

These are colour coded as follows:

• · Green 100mm Cable TV
  · Green 50mm IT
  · Orange 100mm BT / Telecoms
  · Blue 100mm Mains Water
  · Purple 100mm Recycled Grey Water
  · Black 38mm Electricity into dwellings
  · Black 150mm Mains electricity to Plant Rooms

Remote Monitoring:
Remote monitoring of Heat Meters, Electricity, Water and Gas meters will be available to the client from their offices. Diagnostic monitoring of common plant, such as boilers, will be available to the client, and warning systems like sump overflow or oil interceptors will be monitored from base without the need for personnel to make routine but unnecessary calls to site. This alters the maintenance schedule of equipment from routine (but not necessarily required) to maintenance call-outs only as required.

Items remotely monitored:

• · Mains Water
  · Mains Electricity
  · Mains Gas
  · Heat (Flats)
  · Photovoltaic Electricity Export to Grid, performance and fault conditions
  · Petrol Interceptor alarm
  · Central Boiler Heating System - for Faults

It is hoped that one day this technology will assist in reducing unnecessary car journeys and fuel emissions. For example, instead of the utility company visiting the house to read the gas meter, maybe only getting access after several attempts, then returning to base where a bill is printed, which is then delivered by the postman, whereby the occupier then makes a journey to the bank to pay the bill, the meter can now be read remotely, bill sent via e-mail and paid via on-line banking. All this is possible now, with the willingness of the utility companies.

Solar Water Panels
The roof mounted Solar Water panels provide the hot water supply for the houses. These have an efficiency rating of 80%. The average output expected from these units is;
Summer 1.126 kW/hour
Winter 0.926 kW/hour

See side bar for more information

Environmental

Brownfield Site:
The site was originally used as a hard surfaced carpark, with 166 precast concrete garages built on the land.
The concrete garages were demolished and crushed on site, and the resultant pile of material later used as fill under vehicular areas and paths. This avoided adding to landfill sites and unnecessary costs in disposal to licensed tips, and utilised existing materials instead of having to import new.

Elsewhere on site the top Tarmac wearing course was removed. The material under the tarmac was also recycled and used within site as substitute fill under paths and pavements.

Elevations:
Western Red Cedar, left untreated and therefore minimal maintenance.

• · From Managed forests
  · Sustainable material from managed sources
  · Very low maintenance

Timber windows, stained with non-solvent stain.

• · Environmentally friendly stain.
  · Timber from managed sources

Solar Space to front, South-western facing aspect

• · Lifestyle enhancement

Roof:
Extensive Green Roof, whose benefits are:

• · Visually unobtrusive, attractive and compliments the green belt behind site.
  · Improved microclimate, humidifies and cools surrounding air.
  · Protects waterproofing layer from extreme temperatures and abrasion, so waterproof layer durability greatly extended or not required.
  · Reduces drainage of excess water by up to 90% during infrequent precipitation periods, therefore reducing drainage system design and assists in reducing surge on Local Authority system.
  · Low maintenance vegetation, eg: drought tolerant species of Sedum and Succulents.
  · Plants reduce CO2 and emit Oxygen
  · Natural habitat for insects and other wildlife.

Green Roof with PV arrays, Solar Water panels, Passive Stack vents and Sup-pipes, giving natural daylight to the internal staircases.

Grey Water Recycling system:
Water from Baths and wash-hand basins go to an external storage tank prior to treatment and reuse for flushing toilets. (Waste from Kitchens may contain food residue and washing machines will contain detergents, therefore these are not part of the grey water system.).
The flow rate will be remotely monitored to ensure timely replenishment of detergents without unnecessary premature call-out visits.

Surface Water Harvesting system:
Rain water from the dwelling roofs passes down rainwater pipes as usual but is then collected in an underground chamber where it is treated with Ultra Violet light to kill bacterial and stored, used as required for irrigation of the landscaping etc.

Substructure:
Precast Concrete Ground Floor slabs were used. Having longer spans there was no need for additional intermediate foundations, therefore less excavated spoils for foundations and less concrete used in foundations. Also benefited in having a shorter construction programme.

Client

Contractor

St. Engineer

Quantity Surveyor

IT Consultant

M&E Consultants