AHUs And The Ecodesign Rules On Heat Recovery

When it comes to air handling units (AHUs), there are a host of convincing business benefits associated with choosing refurbishment over replacement.

These include price (it can be 35 to 50% less expensive to repair compared with buying new) and the ability to gain the latest technology without the attendant disruption. For instance, AHU refurbishment offers the opportunity to enhance the existing specification by taking advantage of the latest energy efficient EC plug fans and components.

In many cases, upgrading AHUs is more practical too – replacing rooftop plant in city-centre locations, for example, can be a logistical and cost-prohibitive nightmare.

However, there is one knock-down advantage of refurbishment that virtually makes it a no-brainer – heat recovery legislation contained in Ecodesign Directive rules means that, where AHUs are replaced, the new kit will almost certainly need to be much larger to must accommodate heat recovery.

All new residential and non-residential ventilation units are now subject to the requirements of the Ecodesign Directive. This establishes a framework for the setting of eco-design requirements for energy-related products and their implementation.

As of January 2016, all ventilation and fan products have had to comply with Ecodesign and must be labelled with the relevant CE marking.

The directive is designed to drive carbon-emission reductions and help the EU achieve its energy and climate change objectives. Equipment that does not meet the defined minimum requirements can no longer be marketed in the EU.

In most industrialised countries, HVAC are responsible for one-third of the total energy consumption. The main purpose of heat recovery systems is to mitigate the energy consumption of buildings for heating, cooling and ventilation by recovering the waste heat.

Under the directive, AHUs must adhere to certain energy efficiency standards. To achieve these, they often require some form of heat recovery, whether with a thermal wheel, crossflow heat exchanger or run-around coils.

Since these need to be attached to the AHU, this makes the units bulkier and increases their footprint; new units are typically 20% larger than existing plant. This is to cope with the increased heat recovery surface required to achieve compliance.

However, the legislation applies only to AHUs installed after January 1, 2016. Refurbishment comes under separate guidance which means that you don’t have to comply with Ecodesign so the AHUs can remain smaller.

Would AHU refurbishment be a more practical solution for your building? Click here to find out how ECEX can help.