Innovation in demand-based energy recovery ventilation systems will continue to create opportunities for consultants and contractors in the education sector, argues David Cook.
The James Review, headed by Sebastian James of the Dixons group, was set up after backlash to the coalition Government scrapping the Building Schools for the Future (BSF) programme. The review aimed to look at how school building should be carried out in the future and find 'value for money' for the Government against the backdrop of the current spending constraints. In April, the James Review announced its conclusions.

Here's what it said on energy usage: 'It is clear that the cost of energy is continuing to rise. The Regulator has also confirmed that energy costs will rise by 6 per cent over the next decade to revamp the United Kingdom's energy grid. Current movements in energy prices may increase the energy bill to UK schools by as much as £100 million in the next year or two.'

The report continued: 'The review team believes that school-by-school monitoring, clear guidelines and, over time, the roll out of (particularly) electricity management systems can reduce these costs. When applied to a large retail estate these measures reduced consumption (and therefore carbon emissions) by 10-15 per cent.'

Significant potential

From a ventilation perspective, our experience in working with schools has been that there is significant potential to achieve these energy saving objectives and still deliver the air quality needed to create the best possible learning environment.

One of the positives to come out of the original BSF programme was the emphasis placed on the need to provide adequate ventilation into the classroom. Guidance on carbon dioxide (CO₂) levels was an integral part of the scheme, enshrined in the regulatory framework of Building Bulletin 101. This specified limiting CO₂ levels within teaching and learning spaces to 1,500 ppm in recognition of the proven link that exists between indoor air quality and its impact on the academic performance of children. This emphasis on ventilation needs to be continued to provide schools which are not only energy efficient but easy places for children to learn.

The problem with many existing school buildings is that fresh air supply rates per person are often so low (well below what should be the recommended level of between 10-12 l/s) that CO₂ concentrations are well above this figure. This not only impacts upon the learning abilities of pupils, but it also leads to adverse health effects.

As a result, whatever school building scheme replaces BSF, the need for sufficient ventilation will surely remain one of the most significant building services considerations.

The kind of control demanded in the James Review report is essential and this is where demand-based energy recovery ventilation such as our own D-ERV systems can have a major impact, minimising running costs and reducing the reliance on local heating systems.

At Aberdeen's Oldmachar Academy, for example, we have recently retrofitted our Sentinel Totus D-ERV system with a low pressure hot water heater to provide heating and ventilation. The result has been impressive energy savings in classrooms and administration offices as part of a major refurbishment programme at the school. Within its buildings, the school was experiencing major problems with temperature control and the ineffective circulation of air, resulting in 'stale' air being trapped within the classrooms. Aberdeen-based building services consultant CCDP appointed Hutcheon Services to manage the project and install 50 D-ERV units to solve the problem. This new mechanical ventilation system now regulates the room temperature, while providing the required amount of fresh air, keeping CO₂ levels below the prescribed 1,500 parts per million level.

The system's precise control option capabilities are key to providing the required amount of fresh air to the internal rooms while maintaining CO₂ levels. Depending on room occupancy, a change in CO₂ levels is measured by sensors located in each space which then trigger the unit's fan speed to increase or decrease to ensure good ventilation is maintained to meet demand.

Demand energy recovery ventilation also recovers maximum energy (heat and cool) from the extracted air, transferring it into the fresh air supply via the unit's integral high efficiency counterflow heat exchanger. In fact, integrating the unit's on-demand control concept with efficient EC/DC motor technology and the unit's counterflow heat recovery cell, releases up to 90 per cent energy recovery performance.

The result is a system that achieves required airflow rates and ventilates according to precise needs, significantly reducing fuel consumption, energy costs and cutting the carbon footprint of a building by up to 30 per cent more than conventional crossflow energy recovery ventilation devices. Innovations such as these can comfortably reduce the demand on local heating in retrofit projects.

In new build projects, the challenges are different. Demand energy recovery ventilation can ensure that the requirements for excellent levels of indoor air quality are achieved at the same time as its typical 90 per cent energy recovery performance can effectively eliminate the requirement for any additional heating system in the building altogether.

The result will be dramatic savings in capital equipment, installation and fuel costs, and a much more cost and energy efficient school building project.

• David Cook is product marketing manager - non-residential at Vent-Asia