Renewable energy systems from Tata Steel

Published on Thursday, 28 February 2013 12:36

Posted by Vicki Mitchem

Ian Clarke, Technical Application Manager at Tata Steel, explains how renewable energy systems can be integrated with metal building envelopes for non domestic buildings and some implications to be considered.

There is an increasing amount of Global, European and UK legislation, which is targeted to reduce the level of CO2 emissions.  With buildings accounting for approximately 50% of the total UK emissions, much of this legislation has been targeted at improving the energy efficiency performance of buildings.  The scope for cost effectively improving the energy performance of the building fabric any further is reducing and the use of low and zero carbon energy generation is becoming a much more viable option.  Rising energy costs and energy security are also issues that are driving the growth of renewable energy technologies.

By incorporating renewable energy systems into the fabric of the building, the role of the building envelope can be transformed from passive to active, efficient and affordable energy generation.  There are a number of renewable technologies on the market which may be considered, but the two that are most applicable to non domestic buildings and can be fully integrated into the building envelope are active solar air heating systems and photovoltaic panels.

Active solar air heating systems such as Colorcoat Renew SC® by Tata Steel are primarily suited to non domestic buildings where there is a requirement for ventilated fresh air and space heating,  whether they are new build or retro fit. The systems can reduce energy requirements, CO2 emissions and ongoing building operating costs.

Colorcoat Renew SC® works by capturing air warmed by the sun and drawing it into the building through a micro perforated Colorcoat Prisma® pre-finished steel collector installed as an additional skin onto a southerly facing wall, creating a cavity between the wall and the metal skin.  A pre heated boundary layer of air is drawn through the micro perforations into the cavity by a ventilation fan.  This can then either be distributed directly into the building as ventilation air or ducted into the main heating system to reduce energy load.  The system can typically provide up to 50% of a building's daytime space heating requirements, reducing operating costs and energy requirements.  It is recognised within SBEM and therefore contributes to achieving compliance with building regulations as well as helping towards ventilated fresh air requirements for improving occupancy comfort.

As part of the system Tata Steel have developed a user friendly software model that enables feasibility studies, optimum system design and accurate prediction of renewable energy delivery, CO2 savings and payback periods.  As well as a pre-engineered control system to maximise the delivery of renewable heat and enable monitoring and metering for future system optimisation.

Requirements for lighting and cooling a building rely largely on electricity which produces two and a half times the CO2 emissions per kilowatt hour compared with natural gas.  The inclusion of electricity generating renewable technologies such as Photovoltaics into a building design will have a significant impact on reducing the building emission rate as well as ongoing operational costs and reduced energy consumption.

There are various Photovoltaic systems available but light weight crystalline silicon is the most popular for both efficiency and cost reasons.  Modules that can be bonded directly to the panel such as SOLON SOLbond Integra, a unique PV solution that combines the strength and durability of Colorcoat Prisma® by Tata Steel with the powerful, frameless SOLON SOLbond PV modules, can reduce the weight even further and allow easier and faster installation.

The weight of a PV module and framing system is a key issue and must be considered as an additional dead load onto the building structure; Tata Steel would recommend that when choosing a PV system the full structural implications have been calculated and allowed for in the design and that prior to a retrofit a full structural assessment should be carried out.

The PV installation can also create an additional wind load, and the roof must be designed to consider these loads.  The load created will depend on how the PV system is attached to the roof for example as SOLON SOLbond Integra is bonded directly to the roof and is flush with the panel the additional load will be little or negligible.

There is also considerable evidence that the area underneath a PV array is not subject to the same environmental conditions as freely exposed roofing. It is essential to understand the implications of the PV array on the guarantee for the roofing material and specify a material with increased durability that is available with an application specific guarantee.

Colorcoat® products by Tata Steel offer the optimum combination of corrosion resistance, UV resistance and temperature stability, backed by up to 25 year performance guarantees for use with PV systems.

Source: Tata Steel