Delivering the benefits of underfloor heating
Underfloor heating could be the ideal heating solution for commercial properties as James Griffiths of Uponor explains.
Over the last couple of decades, the main heating source in many commercial premises has been a gas boiler. Mirroring the home energy system, it is vastly accepted as the norm. Yet, as underfloor heating (UFH) technologies continue to grow in popularity within the home, so too has interest within the commercial sector.
However, the one key difference is that for many years UFH has been viewed in isolation to the building-management systems (BMS) while it should have been considered at the design stages of the system or, if possible, the building. While the latter isn’t always possible, there are a number of things facilities managers and consultants can consider.
First off, underfloor heating should not be viewed as a one-off investment. While a cheap UFH system may reduce the installation cost, it is highly likely that it will not deliver in terms of energy efficiency — resulting in a higher whole-life-cost ratio than a more efficient system with a higher up-front cost. Crucially the building-services sector needs to move away from a tender mentality and consider the wider benefits of solutions and how they can integrate them into the building structure.
In a new build development or full refurbishment, contractors are required to consider the code levels and design and construct a building with these standards in mind. The key is design, and to help facilities managers to consider the bigger picture. There are also a number of potential options with regards to technology, control and accessories, such as flooring, to help improve performance further.
One particular area where UFH really comes into its own in a commercial environment is heating large open spaces such as atria and large reception areas.
When addressing the heating needs of larger spaces, it is important to consider not just the overall area, but the occupied zone. For example, if people are working on a raised level, floor heating would not be the right technology. However, in most commercial environments the occupied seating zone is within 1 to 2 m of the floor, so any space above 2 m can be discounted as the heat won’t have an impact on the occupants.
As such, concentrating efforts and reviewing the heating requirements of the occupied zone will lead to a dramatic reduction in the necessary heating output, energy consumption and operating costs. This is where UFH offers a distinct advantage over traditional rivals as it is possible to uniformly heat the floor space of the occupied zone with an even temperature.
What’s more with 63% of UFH’s output achieved through radiant heat and only 37% through convection, the heat can be easily localised and air movement minimised, making it ideal for the heating of large open spaces.
On large projects, any weak point in a system’s efficiency can easily result in unnecessarily high energy bills. After going through the installation process, falling at the final hurdle is something that many businesses would no doubt rather avoid.
Balancing is a vital part of the commissioning process but unfortunately not all business owners or facilities managers are familiar with it, and the process is also often overlooked by installers. If a building’s UFH system is not properly balanced it will operate on a uniform flow rate meaning that all rooms — regardless of size or orientation — will receive the same level of output, so some rooms will be overheated and others will be under heated.
A manually balanced system is set based upon a combination of the calculated theoretical design case criteria and an installer’s perceived requirements during the installation. For example, a larger room with a longer loop length will require a greater amount of flow rate or energy to balance it and achieve the desired heating level.
The downside to a manually balanced system is that the installer makes the initial setting based upon their own preferences or perception of how the rooms in a property will be used. Of course these will vary as we all use different rooms in different ways.
One solution is to install ‘auto-balancing’ controls to the manifold, which replaces the need for the manual balancing of the loops. Instead of balancing the system for one peak load, the ‘auto-balancing’ technology calculates the actual energy needs of the individual rooms over the heating season and adapts to those needs, balancing the system through the changing seasons and throughout the property’s changing usage patterns. Crucially, this gives more even floor temperatures and faster system reactions with lower energy consumption than any standard on/off system.
In truth the crux of embedded heating and cooling technologies in today’s commercial buildings is to consider the bigger picture and the options available. We need to move away from the simple concept of pipes in floors to the real benefits of UFH systems and how they can be closely aligned to radiant heating and cooling. In today’s society, where money and environment have become the watchwords of commercial developments, thinking outside the box should be standard practice.
James Griffiths is applications manager for special projects with Uponor.