Prefabricating for time and cost efficiency

Shorter supply chains, less time spent onsite with improved installation and commissioning are all benefits that engineers are able to draw on when dealing with suppliers who understand this rationale to help bring programmes in on time. Here Peter Rees, Technical Director of Tour & Andersson, explains why it is not only operational efficiencies that are borne out of pre-fabricated systems, but technical solutions that provide real value engineering can be delivered in a pre-assembled format too.

A well-controlled HVAC system is one that is adjustable and where faults that may occur throughout the building’s lifetime are easy to locate and resolve.

To measure is to know: in essence hydronic balancing ensures the system performs both during and after commissioning as it was designed to do. In a hydronically balanced system, problems with efficiency derived from fluctuations in flow, pressure and temperature can be removed, preventing the need for extra demands on the pump and boiler, therefore ensuring it runs with both cost and carbon efficiency for the end user.

Most building applications are likely to require a waterborne heating and cooling system with more than one type of valve incorporated within it, in order to deliver the required internal comfort at the optimum energy performance for the whole building.

For example, in a school building there is likely to be a mix of large open classrooms, assembly rooms and indoor sports facilities that place a different demand on the heating and cooling of a system when compared to smaller meeting or seminar rooms within the building. In such instances the system specifier and engineer should work together to develop the optimum blend of solutions to meet all of these needs in a way that is cost effective and efficient to install, as well as maintain over the longer term.

The conditions needed for the HVAC system to operate to design standard initially require that the design flow is available at all terminals. In order for this to happen it must be measured and adjusted on a regular basis.

This can be done through careful sizing of the plant. Hydronic balancing prevents overflow in some circuits from causing underflows in others, detects the degree of pump oversize and generally verifies that the plant works as intended. A hydronic system consultant or designer, in tandem with a knowledgeable valve manufacturer, will be able to recommend the best combination of valves to achieve this.

Consider costs

Where a combination of valves is required it is important to consider the maintenance and lifecosts of the system further down the line. This includes the time taken for the engineer to locate, access and measure each individual valve in turn.

New demands placed on designers and specifiers of shorter installation time frames, flexibility in design for the commercial and public sector, last-minute design changes, as well as time and labour costs, contribute to force installers to find more cost-efficient solutions.

Systems that combine the latest technology for specifiers in a single unit, such as the TA HUB (Hydronic User-Friendly Balancing) that is supplied to site ready for immediate installation, offers time (and therefore cost) savings of at least 20% for installation and over 50% for commissioning, as well as significantly reducing the maintenance time of waterborne systems. Such technology incorporates a number of terminals in the same unit, making access for the engineer fast and therefore enabling maintenance issues and trouble-shooting to be overcome significantly more quickly and with less time taken to allocate and access the valves to do so.

Partnering with a supplier that can provide in-depth technical knowledge and support will ensure that not only the correct blend of valves is selected according to the system requirements, but also ensure that the system is designed with these valves located in the right places. A service such as TA’s Fast Fits offers a completely bespoke solution, taking an efficient approach to system design. This means that instead of having to specify up to eight balancing valves, the whole process is combined. Commissioning is made easier by the installation requiring just one location for anything up to eight terminal units.

Increased satisfaction

Naturally the balancing of a building is easier when fewer locations need to be accessed by the engineer, saving time and therefore cost for the building owner or manager. By installing this type of manifold valve arrangement the access required can also be reduced by up to a factor of eight. This means that balancing will be easier and therefore more efficient, as well as providing a well-balanced system with reduced running costs and increased occupant satisfaction thanks to a well-managed internal environment.

Where there are several terminal units that need to be balanced, or when the building design requires a high level of flexibility – for example in applications where areas are difficult to access such as apartments, office blocks and schools – and when there is restricted access for unauthorised personnel the manifold approach delivers an efficient solution. With 80% of commercial buildings incurring last minute changes in design, an adaptable and accommodating system is required to provide quicker and cost effective re-balancing and fault finding.

It is not just the specification of the correct valves and how these are installed and commissioned that is a key consideration, sophisticated software that can size balancing valves, pipe work and aid in the selection of control valves and pumps will enable the system specifier, installers and building engineer to select a project and decide upon the correct valve and design, with the software forecasting the best results depending on the application.  

Make the right choice

Careful consideration is essential in choosing the correct waterborne system for a building. Taking into account the design and access of a building will determine the system used and where a Fast Fits or manifold prefabrication approach is the right option for saving time and cost during installation, commissioning and ongoing maintenance. Specifying a system that uses pre-assembled parts and is installed in one location will mean that access for commissioning and trouble-shooting is located in one place, eliminating the hassle of a restricted building. In addition to time and cost savings, an accurate and reliable HVAC system that is properly installed, commissioned and balanced, will ensure a comfortable indoor climate with less noise and overall energy efficient operation.

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