A step change in carbon reduction

Action on climate change is gathering pace. The UK Government recently targeted climate change doubters in a prime time TV advert, by sending out the message that climate change is already under way. Meanwhile, the Committee on Climate Change has called for the Government to accelerate carbon emission reductions to meet UK carbon budgets.

A step change is needed. Last summer the Government launched the UK Low Carbon Transition Plan cementing the UK’s position at the forefront of a low carbon economic revolution. However, just a few months’ later Government advisors were already recommending the UK steps up its carbon reduction measures.

October saw the Committee on Climate Change (CCC) publish its first annual report which urges the Government to accelerate carbon emission reductions to meet UK carbon budgets. Unfortunately the report shows UK carbon cuts to be sadly lacking, with emissions falling at 0.5% per year over the last five years.

It is true decarbonising our electricity generation will go a long way to reducing carbon, but this appears to be more of a long-term goal.

So if the Government takes the CCC’s advice then energy efficiency measures could be shortly implemented ensuring carbon is cut across the commercial and public sectors affecting both new build and existing buildings.

But what will this mean to building owners and users? To improve a building’s efficiency it is necessary to mitigate a building’s air leakage. But the key is to ‘build tight and ventilate right’ so as buildings become more air tight we need to ensure they have good ventilation in line with Part F. Ventilation then becomes a key issue since the goal is to reduce carbon which means we don’t want to just extract our efficiently generated and well insulated warm air out of a building.

Currently, the Government still appears focused on clean energy, with renewables seen by many as the silver bullet to cut carbon. But we believe we should be limiting the amount of energy we use, then recovering and reusing it. This is true recycling.

Following the roll out of the Energy Performance of Buildings Directive, and with EPCs and DECs set to become increasingly important, the commercial and public sectors are beginning to show growing interest in recovering energy from their buildings, with Demand Energy Recovery Ventilation (D-ERV) being one type of recoverable system seeing an increased uptake. Designed to operate on the principles of on-demand ventilation, these systems respond to the precise ventilation requirements of a room providing the right level of supply and extract airflow only when required.

Some D-ERV systems are now capable of up to 90% energy recovery, not just heating but also cooling, from the extracted air, transferring it into the fresh air supply via this type of unit’s integral high efficiency counterflow heat exchanger. The result is a system which 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 40% more than conventional crossflow energy recovery ventilation devices.

This type of system’s on-demand operation can be triggered by its response to room occupancy driven by a range of different sensor readings including PIR occupancy detection, CO2, humidity or temperature. These sensors communicate with the main unit which, in turn, drives the fan to the required speed to deliver the airflow and respond precisely to room conditions. Sensors can be combined to generate a hierarchy of control for the ventilation system and ventilation system operation can be easily linked to a Building Management System for monitoring.

Automatic air-conditioning and heating interlocks enable this type of D-ERV system to optimise energy recovery performance further and provide free cooling during summer through bypass optimisation, while a night-time purge facility can reduce start up loads for a building’s air-conditioning and helps reduce over-heat in summer from non air conditioned spaces.

With the Government sending out a clear message that climate change is already under way, the UK needs to cut carbon now. Recoverables  should now be recognised as an important tool within the low energy toolbox.

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