Ventilation and Air conditioning are critical to delivering comfortable built environments.
The quality of insulation materials are constantly increasing and buildings are better sealed than ever. Building Regulations typically require heat recovery with ventilation, and with ever improving product selection and technologies, Sick Building Syndrome is becoming something synonymous with the past.
Tied closely to Building Regulations, the design of Air Conditioning and Ventilation can be complex. But, with that complexity comes opportunity. There are multiple systems available on the market, and in turn there are many Value Engineering opportunities during construction.
Integrating Ventilation with Air Conditioning
On projects with Air Conditioning, ‘traditional’ procurement sees two trades; an Air Conditioning Contractor and a separate Ventilation Contractor. One major way to save both time and money however, is to combine the two.
If you integrate the trades, you will make significant savings. Rather than designing and installing two smaller systems of ductwork, you only have one, albeit larger scheme to manage.
For example, consider a typical office building: you have an open plan office and individual rooms on the perimeter of the floor.
A typical fresh air system would include for ductwork that comes into that floor and is then diverted in and out of each closed space/room on the perimeter.
Integrating the air conditioning with the ventilation reduces the linear meterage of the ductwork required into this area. With two packages, you’d require two sets of ductwork (Fresh Air and Cooling) – the Air Conditioning contractor traditionally arrives second and installs a larger version of the ductwork installed by the ventilation contractor for the fan coils.
It’s common sense that this is uneconomical and inefficient.
With integration, it’s possible to eliminate duplication of ductwork. By routing the fresh air into the fan coil return plenums, you no longer need additional fresh air distribution ducts on the floor. This brings with it three benefits:
- Reduced material costs
- Reduced labour costs
- Reduced management and admin costs owing to fewer subcontractors
Additionally, with fewer subcontractors on site, you reduce the volume of coordination meetings and risk of non-conformities, which reduces the programme and your overall spend.
This is a major Value Engineering opportunity: Main Contractors can deliver a system which performs as specified while simultaneously removing one trade from the programme and saving thousands of pounds in material and labour.
Energy Savings on Cooling
Another Value Engineering opportunity is the use of Variable Refrigerant Volume (VRV) systems in lieu of Chilled Water Systems (CWS). VRV systems are typically comparable in material cost with CWS; however, you can expect to save over 20% on the cost and programme of installation with VRV.
CWS installation effectively requires multiple trades: steel and copper pipework, ductwork and mechanical. This brings with it interfacing requirements, critical path planning and of course non-conformity – all of which adds significant risk. VRV on the other hand only uses copper pipework and usually only one trade is required.
In reality VRV is a simpler, less challenging installation at a lower cost than the CWS alternative. Despite this it still seems to get specified less than CWS. If you’re looking to convince the client of the benefits of VRV, this can be quite simple on projects such as Commercial Fit Outs.
These schemes often have a Comms Room and each floor will have intermittently occupied spaces. With VRV the heat generated from the Comms room can actually be transferred to heat the rest of the building. If you have a sizeable Comms Room, the client could save lots of money long term, making a move to VRV attractive.
The client takes a whole life cost saving and the Contractor takes a saving in time and money during construction.
Integration offers the biggest potential saving in construction, and this can often be in the hundreds of thousands and weeks when it comes to programme saving. Offering this, together with a system that brings whole life cost savings, will often mean the saving in construction is all yours.
This piece was contributed by Stream Enviro. Building on more than 25 years of experience, creating engineered solutions, Stream Enviro is a centre of excellence for bespoke environment HVAC. Read more about Stream Enviro.