Case Studies: St Austell

Roof Module

A major refurbishment of the headquarters of the Ocean Housing Group in St Austell is demonstrating how using a thermally efficient insulated panel system and state-of-the-art photovoltaics from Kingspan, can achieve outstanding results, even in the gloomiest winter weather.

A major refurbishment of the headquarters of the Ocean Housing Group in St Austell is demonstrating how using a thermally efficient insulated panel system and state-of-the-art photovoltaics from Kingspan, can achieve outstanding results, even in the gloomiest winter weather.

The initial phase of the project, which was completed in October 2010, involved replacing an old asbestos roof with over 1200m² Kingspan KS1000 RW insulated panels – a first key step in achieving an energyefficient building envelope. Comparisons between high performance insulated panels with low air leakage and old single skin asbestos sheets show energy savings as high as 90%, so any investment in this kind of improvement will start to save money immediately and will continue to do so over the life of the building. Having ensured that an airtight and well insulated roof would significantly reduce energy demand, the next step was to provide a source of energy generation with the addition of the latest PV technology. In this case the Kingspan Roof PowerPanel system was integrated with the energy efficient BREEAM A+ rated insulated panels, allowing the building owners to take full advantage of the government’s Feed In Tariff (FIT) scheme, and make the investment one that achieves not only a significant building fabric improvement, but also carbon reduction, energy self-sufficiency and energy/income generation.

Matthew Goddard, Commercial Manager for main contractors MITIE Tilley Roofing commented “The programme went really well, and we were very impressed with Kingspan who pulled out all the stops to make sure that the project was delivered on time.”

Two hundred and seventy three Sharp 210W Polycrystalline PV Modules with a 57.33kW peak capacity were installed to the south facing elevations of the roof, in what is believed to be the seventh largest array of photovoltaics in the country and the largest in the South West - 447.72m² in all. A Fronius CL60 Mix Concept inverter ensures that the energy collected by the PV array is converted to electricity, which is then channelled to either service the needs of the building or sold into the National Grid.

“We are in a win-win situation,” explains David Renwick, Chief Executive of the Ocean Group. “All the ‘green’ electricity we generate on site is free for us to use. On top of this we are rewarded for every kilowatt hour of energy we produce, with an additional bonus for the electricity we sell on.”

“The figures really stack up, especially as all the electricity we produce when our offices are closed during the weekend and summer evenings, is sold back to the grid, making us more money,” says David. “And what makes this project really exciting, is that we can now assess the technology for future use in a significant proportion of our homes, with the aim of making fuel poverty a thing of the past for our residents.”

Kingspan’s PV team of engineers were involved throughout the project, from assessing the structural capability of the existing building to support the new roof with the additional weight of the PowerPanel system, to optimising the system design and successfully project managing the complete installation of the PV system. Building modelling was used to simulate the likely output of the system and early comparisons of this data with the actual energy produced are already demonstrating the effectiveness of the system. In the period between 15 October 2010 and 29 June 2011 the system produced 38256.14 kWh of energy, and saved 20.27t of CO₂, - significantly better than the 34451 kWh and 17.81t CO₂ predicted for that same period.

The output will continue to be tracked, providing valuable information on the actual performance of the systems in place. It is estimated that the electricity produced will save over £20,000 annually, with a predicted lifespan in excess of 25 years. Stennack House provides a clear example of how effective the combination of insulated panels with the power of PV can be, and that putting your roof to work is truly the way forward to achieve zero carbon.

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