21/11/17
The Energy Performance in Buildings Directive (EPBD) may still be one of the main drivers of reduced energy consumption in buildings, but could ventilation be playing a much bigger role? Alan Macklin, Group Technical Director at Elta Group, explains why the absence of tangible ventilation requirements is hampering the directive’s impact:
The Energy Performance in Buildings Directive may have been around for some time now, but with the EU’s policymakers currently exploring possible improvements to the legislation, it seems timely to consider exactly what we’d like to see from its next update. After all, with 2020 energy targets becoming ever-closer, there is no doubt that the drive towards better performing buildings needs to quicken.
A notable absence from the legislation up to now has been any standards which define specifically what comprises good Indoor Air Quality. Granted, this may well change given early suggestions that the next version of the directive will detail some form of standard designed to ensure minimum health and comfort levels, but we remain in a position where ventilation requirements fall some way short of other areas of focus, such as heating or lighting, for example.
When we do finally see actual, tangible targets for indoor air quality, manufacturers will be able to follow suit by bringing fans, air conditioning systems, and air handling units to market which deliver to these targets in the most practical and efficient way possible.
That said however, one challenge looks likely to still remain, and that is the need for the ventilation performance within a building to be monitored on an ongoing basis.
AN ONGOING PROCESS
Ventilation rates in buildings have a tendency to fall short of their original performance specification over time as the characteristics of the building change. The usage of the building itself, the equipment within it, and its level of occupancy throughout the day can all affect air quality, so there is a clear need for levels to be checked regularly over time.
Ventilation rates are prescribed by the Building Regulations, but it is only through regular monitoring – and adjustment where required – that these prescribed rates can be maintained. By introducing a requirement whereby ventilation systems have to be checked every two years or so, the policymakers would be going some way towards ensuring the occupants of a building are all but guaranteed to be enjoying adequate air quality. Without this however, we are simply left vulnerable to blocked filters, faulty systems, and a whole plethora of potential issues which limit the capacity for a system to operate as intended.
EFFICIENCY ON DEMAND
While we remain hopeful that we may see some form of monitoring requirement in the not too distant future, the air movement industry is working on systems which are capable of self-regulating air quality without necessarily needing to be kept under such a watchful eye.
When it comes to the ventilation systems available to specifiers and contractors, we’re now in a position where Demand Controlled Ventilation can be installed within a building to adapt to the demand of the occupied space. Such systems ensure the space is provided with the right amount of air, while energy consumption is reduced, yet there is no real encouragement for this type of technology within the EPBD.
The latest Demand Controlled Ventilation technology operates by using VAV diffusers, which effectively control ventilation levels by regulating airflow according to the air quality. By relying on a self-regulating system, building users may only need to check their ventilation levels once every three years or so, safe in the knowledge that their DCV can adjust itself whenever the air quality fluctuates – and in doing so, energy efficiency is maximised at the same time.
The fact is, Demand Controlled Ventilation should have a much higher profile within the legislation that covers the energy our buildings use. Modern buildings need to be flexible to accommodate fluctuations in occupancy levels, yet need to also deliver energy efficiency, so the fact that systems which can do this automatically are not given any real profile is a huge missed opportunity. In the similar vein, a look at the Renewable Energy Directive, which rewards the use of heat pump technology, raises the question of whether more could be done to encourage the use of heat recovery units or heat retention fans – both of which act in a similar manner by making use of heat which would otherwise be released into the atmosphere.
In their present guise, the standards governing energy use in British buildings appear guilty of failing to acknowledge how modern ventilation methods can help to achieve maximum comfort and health levels for occupants while boosting energy efficiency. Up to now, ventilation systems have generally been regarded as an out of sight, out of mind product category, but it is high-time that stance was changed.
For further details on Elta Group Building Services’ wide range of HVAC products, please visit egbuildingservices.co.uk.