Chilled beams and ceilings continue to make their mark
The potential for energy efficient comfort cooling made possible by chilled beams and ceilings continues to open up new opportunities. Andrew Gaskell of the Chilled Beams & Ceilings Association examines the drivers.
The use of chilled beams and ceilings within the UK market has for many years been associated with commercial offices. The popularity of these systems within this sector is due mainly to the inherent energy savings available as a result of operating with elevated chilled water temperatures (typically 14°C flow), but also due to the ability of chilled beams and ceilings to provide high levels of indoor comfort with lower air movement and less noise than other common forms of mechanical air conditioning, all of which have been proven to increase workplace productivity.
|Note the use of chilled beams in this IT room in the Hallwood Building at Nottingham University.|
The implementation of Building Regulations (Part L) has forced building designers to look for new ways of improving building performance by using renewable technologies, improved building envelope and energy-efficient mechanical and electrical systems. In most instances improved building design has lowered the peak cooling demand, meaning that more and more projects have fallen into the category where chilled beams or chilled ceilings could now be utilised.
The continual tightening of this legislation around the performance and energy consumption of all buildings, along with rising energy costs, have increased the use of chilled-beam technology beyond commercial offices into other sectors where the benefits of chilled beams and ceilings can be fully realised. This increase in use of chilled-beam technology has also driven the latest generation of beams which can deliver higher levels of cooling, or alternatively the same levels of cooling at higher water flow temperatures (typically 16 to 17°C) which enables additional free cooling from a dedicated chiller, resulting in even greater energy savings.
This increased variety of chilled-beam applications has been driven by engineers, designers and building owners — all looking to investigate alternative and more energy-efficient cooling solutions than had previously been the norm within these sectors in order to comply with the relevant legislation but also to help reduce running costs.
Three such examples of sectors where chilled beam technology has expanded are the healthcare (hospitals), education (universities and academies) and the leisure (hotel) sectors. These sectors readily lend themselves to chilled-beam and chilled-ceiling technology, as the occupier, in most instances, owns the building — so the full benefit of reduced running costs, low maintenance costs and long life expectancy are retained by the client.
The adoption of chilled beam technology within the healthcare sector has been widespread, with installation examples throughout the UK and overseas. The popularity of chilled beams and ceilings within hospitals can be attributed to a number of key benefits when compared to alternative solutions such as the following.
|Active chilled beams are used throughout The Queen’s Medical Centre, Nottingham, with the exception of invasive surgery.|
Infection control: The closed-case design prevents the transfer of air from the room into the ceiling void and vice versa. The design of chilled beams and ceilings also allows deep cleaning of all elements without opening the ceiling void, preventing any cross contamination.
Planned preventative maintenance (PPM): Chilled beams and chilled ceilings have no moving parts, so maintenance requirements are substantially reduced. The only real maintenance is a periodic clean to the facia and removal of any dust on the heat exchanger, which could be as little as once every four to five years, depending on the specific installation.
Life span: Since there are no moving parts, the life expectancy of the whole product should be in excess of 30 years (subject to water quality) which means that there is no periodic replacement of parts such as filters or fans — in fact, no replacement parts at all. This is especially important for projects such as hospitals where regular access to patient rooms can be difficult and subject to occupation and where the relevant FM company may be responsible for the building for long periods of time.
There are numerous examples of both chilled-beam and chilled-ceiling technology being used within the education sector. Chilled-beam technology lends itself to the education sector where increased indoor air quality, low noise levels and increased comfort levels have been proven to increase pupil attainment.
Traditionally, these projects have used active chilled beams due to the requirement to provide fresh air into the classrooms. More recently however, many education projects are adopting a mixed-mode approach where passive chilled beams have been combined with a natural-ventilation system to provide cooling during peak times whilst limiting the amount of energy consumed by removing the central air-handling unit.
As the technology matures, manufacturers are looking for ways to improve the efficiency of the system to ensure its continued market growth. High-performance units now allow designers to select active chilled beams with lower static pressures (reducing the power consumption of the AHU) and running chilled beams and chilled ceilings with higher water temperatures (typically 18.0°C flow), which coupled with free-cooling chillers or renewable ground- or air-source technologies results in considerable energy savings since free cooling can be attained over many months of the year.
The leisure industry has also made use of the more energy-efficient chilled-beam and ceiling technology, with the substantially reduced routine maintenance a key driver for large corporate chains. One part of the leisure sector in particular (hotels) has utilised the technology to provide cooling and heating to hotel rooms because of its advantage over alternative systems. Chilled beams and ceilings can provide a superior indoor environment with lower air movement and greatly reduced noise levels because they have no moving parts or fans.
Andrew Gaskell is technical co-ordinator for the Chilled Beams & Ceilings Association within FETA.