Building plans began with the standard off the shelf timber frame provided by Scotframe. The plans were customised to incorporate two wings – a sunroom and office with utility room and big room above. The interior of the house was reconfigured and we decided to clad the exterior structure with timber shiplap cladding. A timber frame structure was selected as it is lightweight and well insulated which, in-turn, takes less energy to heat.
The whole of the UK, including Shetland, is viewed as a maritime environment. Lightweight structures operate much more efficiently in this kind of environment, taking less time to heat. The design of the structure had to take into account the severe weather conditions of Unst. The Scotframe structure is very substantial - not a stick frame structure - and the wall plate is anchored to the underbuild at 400mm centres using stainless steel bolts which should allow the building to endure the extremely strong winds that can often occur in this area.
The house was shipped to Unst on two articulated loads. These loads included the complete house, minus the roof e.g. frame, insulation, doors, windows, plasterboard and flooring.
We decided to overspec the house insulation. All external walls and the entire roof are insulated with 140mm of Celotex expanding foam which gives excellent thermal properties. The windows are filled with argon gas – again this enhances the heating for the house.
We are working with Sir John Samuels of Refuel Research - the flow battery/fuel cell research company – to install the first domestic flow battery in Europe that will support a domestic dwelling.
We have also developed a water battery, which is a 4200 litre GRP tank with 200mm of Celotex insulation. This is the buffer tank for the air-to-water heat pump and the underfloor heating system. Within the top of this tank is a large titanium coil. The water from the water main passes through this pipe and picks up thermal gain and is forced up to a stainless steel insulated hot water tank by gravity. An external in-line water heater senses the input warmed water from the domestic hot water tank and raises it to a pre-set temperature, on demand, once a hot water tap is turned on. This is the first time a system like this has been in operation and it can produce1000 litres per hour.
We are also proposing to light the entire house using the same energy consumption as a 100w bulb, with the aid of LEDs.