Paul Osborne, Aermec’s Service Manager looks at how a robust HVAC service and maintenance strategy in place can drive down carbon emissions in buildings and that attention to detail and preventative measures can have a considerable impact on performance levels and energy consumption.
It is estimated that office buildings waste up to £60million per year, one of the most effective ways for facilities and buildings managers to minimise the impact on climate change and boost their eco-credentials is to overhaul their HVAC service and maintenance strategies and keep systems fully maintained. By taking steps to increase efficiencies and scale down energy usage they can help mitigate increases emissions, carbon footprints and minimise the environmental impact.
Whether the facility is an office complex, school or hospital, HVAC service and maintenance can ensure any problems are addressed swiftly to prevent uninterrupted operation of buildings or mission critical sites.
Chillers and AHUs can be kept operating at peak performance levels by having annual pre-season check-ups which means having a robust PPM strategy in place. Service engineers are always busier in the summer and winter months, so it pays to have cooling systems checked in the spring and heating in the autumn. Some buildings do both.
There is no ‘silver bullet’ or one size fits all approach when it comes to reducing emissions, but annual HVAC preventative maintenance programmes (PPM) should include a wide range of measures, such as lubricating all moving parts, lack of lubrication can lead to friction in motors which could see a rise in electricity usage and the tightening of electrical connections to ensure the safe operation of systems and maximise the life of major components.
Many tasks can be tackled by service engineers on site such as changing filters, tightening or replacing seals, checking thermostats and electrical components, but where larger potential issue have been flagged, these may require a separate service visit.
When it comes to cooling specifically one of the tasks often overlooked is coil cleaning and the cleaning of evaporators. An ASHRAE study showed that cleaning coils could improve energy efficiencies. Yet all too often cleaning the coils on air cooled chillers and condensers are disregarded in a bid to cut costs – dirty coils can increase compressor energy consumption by as much as 30% but can also compromise heat transfer.
Over time contaminants can build up on the surface of the coils of the heat exchanger and will start to act as an insulator, decreasing the available surface area for heat transfer, resulting in excessive energy consumption, poor system performance and the life of HVAC equipment will be shortened.
Compressors also require attention. Some components need to be replaced every few years in order to extend the life of the compressor.
Checking refrigerant levels are another essential – too little or too much will make systems less efficient, increase energy usage and reduce the life of your equipment. It pays to test for leakages too which can damage the environment, but make running systems more costly and less reliable.
Some chillers have been in situ for in excess of 20 years. Their longevity lays testament to the effectiveness of a good service and maintenance programme.
However, there comes a point when a compressor has expired and not only is it more cost effective to replace the entire product but newer technologies can result in impressive energy savings, pay backs depending on the site and installation requirements and a reduction in carbon footprints.
Newer technologies require just as much attention as older systems. Chiller technology has advanced considerably. Systems that have a high SEER rating can when forced to run harder than is necessary, lose much of their effectiveness, scheduling regular inspections can maximise investments and ensure optimal performance.
Ductwork is a huge part of an HVAC system and play an important role in any HVAC system. It transports the air breathed by a building’s occupants, poor quality air can not only result in sick building syndrome – dry eyes and sore throats – but can also affect the transmission of bacteria and viruses.
Once installed ductwork can’t be easily changed, it has no built-in redundancy either, so it pays to design and install ductwork effectively and consider whether systems with UV technology can be retrofitted to buildings requiring hygienic air flows.
All HVAC systems are designed for a small amount of system volume leakage. But high leakage levels can result in AHUs using more energy, running for longer periods and also faster to try and maintain pressure. Efficiency can also be compromised with hot and cold spots.
Other than dampers, ductwork has no moving parts ensuring maintenance is straightforward and inexpensive. But checks for air tightness should be carried out as leakages can result in lower flow rates or and/or indicate blocked air flow passages which can influence the IAQ and affect performance levels.
Keeping Energy Performance Certificates updated (EPCs are valid for 10 years), regular inspections of kit and making sure all your assets are accurately recorded, verified and accredited by the appropriate body such as BREEAM can all help boost the environmental credentials of buildings.
A good HVAC service and maintenance strategy is more critical than ever. It can improve the performance equipment, reduce maintenance costs, deliver greater efficiencies and life cycle costs but more importantly, reduce the impact on the environment.