When to refurbish?
There are many situations where refurbishing existing air handling plant is a more cost-effective option than replacing with new.
When it comes to establishing a sustainable policy and minimising environmental impact, energy efficiency generally dominates the headlines. And while this is clearly an important consideration there are other factors to consider as well.
In existing buildings, for example, there are often opportunities to refurbish major items of plant such as air handling units (AHUs), even those 20-30 years old, instead of replacing them. Not only does this reduce material consumption and embodied carbon, it also creates an opportunity to upgrade the performance of the plant while reducing costs and disruption.
To put this into perspective, consider a 2m x 2m x 6m AHU with an airflow of 7m3/s. It incorporates a volume control damper, bare tube frost coil (LPHW), panel filters to F4 efficiency, bag filters to G6, CHW cooling coil, LPHW reheat coil, fan and motors - and would cost £12,500 to supply and install, based on good access.
To refurbish a similar unit, replacing all internal components, treating any corrosion, replacing damaged external panels, re-commissioning and providing a 12 month warranty would cost £9,125 – a saving of 27%.
In fact, depending on circumstances and the level of experience and expertise applied to the project, the savings achieved by refurbishing will typically range from 20% to 50%. Furthermore, there will be additional life cycle cost savings through reduced maintenance costs and improved energy efficiency, all providing a fast return on investment. A recommissioned system and updated Operation & Maintenance manuals will also contribute to reduced cost of ownership.
Why refurbish?
There are many reasons to consider refurbishment, ranging from deterioration of components and casework through to a desire for higher performance and/or improved efficiency.
Clearly, all AHU components will suffer some age deterioration. Condensate mixed with airborne pollutants may cause corrosive oxidation of cooling coils, for example, There will also be wear and tear on moving parts in fans and motors, while static components may have years left in them.
For these reasons, an initial inspection to identify opportunities for refurbishment is the first stage in any such project; followed by a method statement, risk assessment and detailed costings.
Very often, it will also make sense to take the opportunity to improve performance. In such cases, existing components can be replaced with newer designs that comply with modern standards and specifications, while also offering improved efficiency. For example, it may be possible to replace original standard fans driven by AC motors with more efficient backward-curved fans and DC motors. Similarly, heat transfer across heating and cooling coils has improved in recent years, as has the efficiency of filters and the thermal and acoustic insulation of replacement AHU panels. The same principles are true of any direct expansion refrigeration equipment installed in the AHU.
Where a major upgrade to performance is required, or where major deterioration has occurred, it is also possible to replace whole sections or, indeed, introduce new sections. In such cases, if access is restricted, these may be taken to site and assembled in situ.
In fact, this highlights another major benefit of refurbishment, as there are many buildings where access to the AHU plant is very difficult, so that refurbishment becomes a much more sensible option. When planned properly, refurbishment is also less disruptive compared to a new installation as the work can be carried out in phases outside normal working areas. Also, units serving critical areas can be isolated so the work is phased to suit the needs of the building’s occupants.
Clearly, then, there are many good reasons to consider AHU refurbishment as an alternative to replacement. The key is to harness the expertise of specialist companies that have extensive practical experience of AHU refurbishment and can deliver a complete turnkey solution.
There are many situations where refurbishing existing air handling plant is a more cost-effective option than replacing with new.
When it comes to establishing a sustainable policy and minimising environmental impact, energy efficiency generally dominates the headlines. And while this is clearly an important consideration there are other factors to consider as well.
In existing buildings, for example, there are often opportunities to refurbish major items of plant such as air handling units (AHUs), even those 20-30 years old, instead of replacing them. Not only does this reduce material consumption and embodied carbon, it also creates an opportunity to upgrade the performance of the plant while reducing costs and disruption.
To put this into perspective, consider a 2m x 2m x 6m AHU with an airflow of 7m3/s. It incorporates a volume control damper, bare tube frost coil (LPHW), panel filters to F4 efficiency, bag filters to G6, CHW cooling coil, LPHW reheat coil, fan and motors - and would cost £12,500 to supply and install, based on good access.
To refurbish a similar unit, replacing all internal components, treating any corrosion, replacing damaged external panels, re-commissioning and providing a 12 month warranty would cost £9,125 – a saving of 27%.
In fact, depending on circumstances and the level of experience and expertise applied to the project, the savings achieved by refurbishing will typically range from 20% to 50%. Furthermore, there will be additional life cycle cost savings through reduced maintenance costs and improved energy efficiency, all providing a fast return on investment. A recommissioned system and updated Operation & Maintenance manuals will also contribute to reduced cost of ownership.
Why refurbish?
There are many reasons to consider refurbishment, ranging from deterioration of components and casework through to a desire for higher performance and/or improved efficiency.
Clearly, all AHU components will suffer some age deterioration. Condensate mixed with airborne pollutants may cause corrosive oxidation of cooling coils, for example, There will also be wear and tear on moving parts in fans and motors, while static components may have years left in them.
For these reasons, an initial inspection to identify opportunities for refurbishment is the first stage in any such project; followed by a method statement, risk assessment and detailed costings.
Very often, it will also make sense to take the opportunity to improve performance. In such cases, existing components can be replaced with newer designs that comply with modern standards and specifications, while also offering improved efficiency. For example, it may be possible to replace original standard fans driven by AC motors with more efficient backward-curved fans and DC motors. Similarly, heat transfer across heating and cooling coils has improved in recent years, as has the efficiency of filters and the thermal and acoustic insulation of replacement AHU panels. The same principles are true of any direct expansion refrigeration equipment installed in the AHU.
Where a major upgrade to performance is required, or where major deterioration has occurred, it is also possible to replace whole sections or, indeed, introduce new sections. In such cases, if access is restricted, these may be taken to site and assembled in situ.
In fact, this highlights another major benefit of refurbishment, as there are many buildings where access to the AHU plant is very difficult, so that refurbishment becomes a much more sensible option. When planned properly, refurbishment is also less disruptive compared to a new installation as the work can be carried out in phases outside normal working areas. Also, units serving critical areas can be isolated so the work is phased to suit the needs of the building’s occupants.
Clearly, then, there are many good reasons to consider AHU refurbishment as an alternative to replacement. The key is to harness the expertise of specialist companies that have extensive practical experience of AHU refurbishment and can deliver a complete turnkey solution.
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Refrigeration Equipment