Low carbon design of three new industrial units

Blaenau Gwent County Borough Council were looking to build 3 low carbon industrial units in Ebbw Vale, South Wales. The LCBE team have undertaken computer modelling to enhance the design to reduce energy requirements.

As part of the re-development at The Works site, 3 new factory buildings were proposed, 2 separate larger units and one smaller unit. Each unit will be divided into 2 areas, with office accommodation to the front and workshops to the rear. The larger units are designed to have offices on the upper floor, whilst there will only be one level in the smaller unit. Skylights will provide daylight for the double height workshops.

Computer models of the units were created to explore solutions that would reduce heat loss and enable on-site energy generation using solar power.

Objectives

The objectives were to:

• optimise the design to achieve a low energy industrial environment while maintaining comfort
• integrate renewable energy generation and storage technologies where appropriate to reduce on-site energy consumption
• demonstrate the benefits of replicable low carbon solutions at an industrial scale using modelling

Low carbon solutions

Low carbon solutions included:

• reducing energy demand by using high quality building materials and Passivhaus standards
• adopting passive design principles to take advantage of natural daylight and heat that can be gained from the sun
• installing low energy lighting and an air source heat pump (ASHP) or ground source heat pump (GSHP)
• investigating the potential to generate renewable energy using solar panels
• analysing whether heating demand within the units can be reduced by using warmed air from a transpired solar collector combined with a mechanical ventilation system with heat recovery

Outcomes

The computer modelling has enabled the team to make the following recommendations:

• LED lighting could reduce both the overall running costs and the related carbon emissions by up to 21%
• there were limited benefits from using warmed air from a transpired solar collector combined with a mechanical ventilation system with heat recovery and so these technologies have not been recommended for the units
• an air source heat pump could decrease carbon emissions and provide extra income through the Renewable Heat Incentive scheme (RHI)
• the roof of the smaller unit was originally designed to slope north but by altering it to slope towards the south instead solar panels on the roof would generate more energy
• energy generated by solar panels combined with battery storage could achieve a self-sufficiency ratio of 76% for the units

If all of the above options were incorporated into the design of the new units, negative annual CO_² emissions could be achieved.

A net profit was possible as annual income through the Feed-in Tariff (FIT) and RHI at that time was more than the proposed annual operating energy bill.

Lessons learnt

Orientating the roof of the smaller unit to the south will increase the energy generated by solar panels.

It was important that the computer modelling reflected how the building would be used as this affected fresh air delivery and the performance of the ventilation system (MVHR and TSC).

Selecting renewable energy generation technologies which are suitable for the site is an important consideration. This site is located within a valley and so the surrounding hills would prevent sufficient energy being generated from wind. Modelling showed that solar power was suitable and overshadowing due to the steep valley sides only reduced the energy generated by the solar panels by 4%.

The project has demonstrated the benefits of using computer modelling to inform building design and supported the fact that the whole energy system-based approach could be applied to industrial units.

Project team

The project team includes:

• LCBE team at the Welsh School of Architecture, Cardiff University
• Technical Services Division at Blaenau Gwent County Borough Council