Carbon Trust guide helps reduce CO² in non-residential exisiting buildings

The Carbon Trust has published a new guide to help cut down carbon emissions in existing non-residential buildings.

Called Low Carbon Refurbishment of Buildings, the manual aims to show how a low-carbon refurbishment does not have to be complex.

According to Carbon Trust data, non-domestic buildings account for nearly one-fifth of the UK’s carbon emissions. Given that 60% of the buildings that will be standing in 2050 have already been built, low-carbon refurbishment of existing buildings will be essential to hit government carbon reduction targets.

Dr Mark Williamson, director of innovations, said: “Building refurbishment offers significant opportunities to cut carbon, but without corporate commitment and a focus on carbon at every stage of the project, the potential benefits can leak away.

“Given tightening legislation on energy performance and increasing energy prices, organisations need to put carbon reduction at the heart of their refurbishment plans.”

According to the report, nearly all building refurbishments offer opportunities to reduce carbon emissions, but conventional projects often miss the opportunities available, leading to unintentional increases in energy use.

The guide is based on the Carbon Trust’s experience of working with non-domestic refurbishment projects as part of its Low Carbon Building Accelerator.

The programme is following 10 typical projects through the entire design and refurbishment process as well as monitoring building performance afterwards.

One of these is the John Lewis Partnership, which has been working with the Carbon Trust on the refurbishment of its flagship John Lewis department store on Oxford Street in London.

The group decided to use magnetic bearing chillers following a detailed analysis of peak and off-peak performance throughout the year. It was found that these demonstrated a simple payback period of 3.7 years despite an increase in capital cost of 50% relative to standard chillers. The estimated energy savings were of the order of 750MWh per year and cost savings £54,000 per year.

Bill Wright, corporate energy and environment manager at the John Lewis Partnership, said: “We are now taking many of the learnings from Oxford Street and applying them across our business. We are also happy to share best practice with others – including our competitors.”

The LC (former Swansea Leisure Centre) also turned to the guide to cut down emissions in its building.

As part of the City and County of Swansea’s sustainability policy, there was an aspiration for the refurbished leisure centre building to be energy efficient. A number of key measures were included in the base design and budget as part of the ambition to reduce the environmental impact of the building. These included high insulation values, gas-fired combined heat and power, use of energy efficient lighting, extensive lighting controls, heat recovery on air handling units, high efficiency motors and variable speed fans and pumps.

The Carbon Trust’s consultants identified some additional approaches to reducing the carbon emissions, including a biomass boiler, backwash heat recovery, water cooled ammonia chillers and plant room heat recovery. Based on the carbon emissions reduction, an additional sum of £500,000 (2% of the original budget) was included within the project budget to cover these measures.

The modelling was able to demonstrate that the best option for reducing carbon emissions was the clear glazing solution, due to the ability to make use of free heating from increased solar gain during the majority of the year.