Experts from the Welsh School of Architecture (Cardiff University) have designed and built Wales’ first low-cost energy positive house. The "Smart Operation for a Low Carbon Energy Region" (SOLCER) House is capable of exporting more energy to the national electricity grid than it uses, in an attempt to meet tough new targets for zero carbon housing.

The three-bedroom house, designed by Professor Phil Jones and his team, is located on the site of Cenin Renewables, Ltd in Pyle, near Bridgend, in Wales. Designed and constructed as part of the Wales Low Carbon Research Institute’s (LCRI) SOLCER project and supported by SPECIFIC at Swansea University, this unique design debuts the combination of a reduced energy demand, renewable energy supply and energy storage which, in effect, has created an energy positive house.

In order to drastically reduce the energy demand, the house was built with high levels of thermal insulation, reducing air leakage, and uses an innovative energy efficient design which includes low carbon cement, structural insulated panels (SIPS), external insulated render, transpired solar collectors (TSC) and low emissivity, double glazed aluminium clad timber frame windows and doors.

The house’s energy systems combine solar generation and battery storage to power both its combined heating, ventilation, hot water system and its electrical power systems which include appliances, LED lighting and a heat pump. The TSC solar air system preheats the ventilation air which is topped up from a thermal water store.

The south facing roof is comprised of glazed solar photovoltaic panels which are fully integrated into the design of the building and thus allow for the roof space below to be naturally lit. This has been designed to reduce the cost of bolting on solar panels to a standard roof.

Project team

Principal Investigator: Prof. Phil Jones

Project Manager: Dr. Jo Patterson

Architect & researcher: Ester Coma Bassas

Researcher: Dr. Xiaojun Li

Monitoring team: S. Lannon & H. Jenkins

LCBE team: R. Williams & E. Doe

Academic partners

Specific

Swansea University

University of South Wales

Glyndwr University

Time schedule

Design: n.d

Construction: The SOLCER House took a total of 16 weeks to construct and was completed in February, 2015.

Delivery: It officially opened its doors on 16 July 2015.

Building use / surface

New two-storey residential building

Total usable floor area: Approximately 100 m2

Construction costs

Total estimated cost: £125,000 (£1,000 m², compared with the social housing benchmark of £800 - £1,0000m²).

The project has been partly funded by the European Regional Development Fund through the Wales European Funding Office.

Envelope performance

Foundations: Incorporation of Cenin’s low carbon cement to minimize embodied energy (the energy required to create the house).

Structure/walls: Use of 194 mm Structural insulated panels (SIPS) being thicker than the 150 mm standard. U-value (a measure of heat loss) is just 0.14 for these panels. External wall render minimises risk of thermal bridging and brings overall wall U-value to 0.13. The house also features BASF Neopor insulation material.

Roof: An asymmetrical roof with a larger south-facing pitch, allowing for photovoltaic panel installation.

Windows: The house uses aluminium clad timber windows incorporating Pilkington energiKareTM energy efficient glazing, supplied by Cardiff-based Vellacine.

Energy consumption

The predicted energy performance is 70% autonomous, with a 1.75 grid export-to-input energy ratio (see consumption chart for more info). For every £100 spent on electricity used, it should be able to generate £175 in electricity exports.

The embodied CO₂ of the house materials is 340 kgCO₂/m², compared with standard house benchmark of around 500 kgCO₂/m².

Energy systems

The energy systems combine solar generation and battery storage to power both its combined heating, ventilation, hot water system and its electrical power systems which include appliances and LED lighting.

In winter, space heating is provided by passing external air through the upper south facing transpired solar air collector (TSC) which goes through a mechanical ventilation heat recovery unit (MVHR) and then is delivered to the destined space. Exhaust air is passed through the MVHR and then through an exhaust air heat pump which heats the thermal water store. The thermal store heats domestic hot water (DHW). The heat pump is powered by the PV and battery storage system.

The house uses grid electricity supply when the PV - battery system is exhausted.

Specific details:

PV panels: 40 m2 of photovoltaic panels integrated into clear glazing made by GB-Sol which is based in nearby Pontypridd, provide 4.3 kWp of energy.

Batteries; The 20 m2 north facing roof section houses 6 lightweight lithium ion batteries from Victron Energy, with a total 6.9 kWh capability.

Transpired solar collector: 17 m2 transpired solar collector. A double metal skin. The outer layer has tiny perforations that allow heat from the sun to be captured in the cavity between the two layers. The warm air is then drawn into the ventilation system and distributed throughout the building.

Heating, ventilation and hot water: The house has mechanical ventilation with heat recovery (MVHR). Warm air from the transpired solar collector goes to the 450 W heat pump in winter, where it preheats ventilated air. Heat from the exhaust air warms the domestic hot water supply (DHW).

Lighting: LED lighting is fitted throughout.

Appliances: All of the domestic appliances are A+ rated.

Awards

Winner in the 17th Innovation & Impact Awards 2015 for the category “Innovation in Sustainability Award” promoted by Cardiff University (http://www.innovation-network.org.uk/innovation-awards/awards/innovation-in-sustainability-award.aspx)

For further information, please visit the relevant SOLCER website and the relevant Cardiff University website.

Additional Links

Construction process in 16 weeks: https://youtu.be/6w9g4A-9Hq4

Project description: https://www.youtube.com/watch?v=Kgi4S89AVgY

Other (under Environment, The greener house effect, pg.26): https://business.wales.gov.uk/sites/business-wales/files/documents/Advances%20Wales%2077.pdf