AIR CONDITIONING, COOLING & VENTILATION An efficient solution that ticks all the boxes W Andrew Gaskell,
Chairman of the Chilled Beams & Ceilings Association, explains why the flexibility of Chilled Beam Technology makes it a solution that ticks all the boxes for building managers concerned about saving costs, energy efficiency targets and a comfortable working environment.
ith energy prices continuing to rise and energy efficiency becoming more
important as the UK aims to hit its net zero by 2050
target, more and more businesses across the UK are looking for ways to improve the energy efficiency of their premises without adversely affecting their indoor working environment.
The UK’s commitment to achieving Net Zero by 2050 has shown us taking a leading role in enabling us to protect our planet, and the Chilled Beams and Ceilings Association (CBCA), as part of the Federation of Environmental Trade Associations (FETA), will be at the forefront of crucial action because we are able to provide services that can heat and cool buildings using more energy efficient methods. Chilled beams and radiant chilled ceilings have been with us for many years. However, it is only more recently that building services design engineers and end users have begun to embrace the aesthetic, environmental and comfort attributes of an approach that is now generally regarded as the most space efficient and environmentally friendly method of heating and cooling a building. The technology may not be the most appropriate system for every building project - no HVAC system is the best solution as one size doesn’t fit all. However, there are a growing number of applications where chilled beam technology is ideal – particularly in commercial office developments, hotels, universities and hospitals, given the high energy efficiency, long life expectancy and low maintenance, low carbon and optimum in thermal comfort.
At a time when sustainability is higher up the building engineer’s agenda than ever, a system that uses minimal energy to achieve excellent comfort conditions (category B of BS EN ISO7730), involves no moving parts, has a long lifecycle and is designed for decommissioning with 100 per cent recyclable components ticks almost every box.
Chilled beams and chilled ceilings require a
relatively modest cooling water temperature (14–17°C), which can be obtained using natural cold water storage or free cooling from outside air over periods of the year depending on climate. Also, when mechanical cooling is used, a better energy performance can be achieved by use of free cooling chillers given the higher coefficient of performance (CoP). Where chilled beams are used for heating, the situation is similar in that it is possible to use low temperature heat sources or heat pumps with water flow temperatures of typically 30–45°C.
Flexibility
A wide variety of chilled beams and chilled ceilings are currently available, with both off-the-shelf and bespoke variants. The size, shape and colour of products/solutions can be varied to meet specific requirements, as can the paint finish. There is a common misconception, particularly in the UK, surrounding the lack of flexibility in chilled beam systems. In fact, building managers and commercial letting agents are potentially missing out on significant savings by overlooking chilled beams as an energy- efficient HVAC system.
Flexibility can be designed into the system solution for future cellularization to a pre-agreed planning grid as tight as 1.5m x 1.5m and most often designed to cater for a 3m x 3m partitioning grid availability. In recent years, multiservice chilled beams (MSCBs) have become increasingly popular in commercial settings as they can incorporate a full range of other services to meet specific user requirements, such as heating and cooling, ventilation, lighting, and even AV equipment, fire alarms and public address systems. Other advantages include the fact that chilled beams operate above dew point, so there is no condensation drains or pans which can harbour bacteria and mould, meaning not only less maintenance, but also a much healthier environment for occupants. Chilled beams can also provide demand control ventilation (DCV) without needing moving parts on the beam itself as a ‘turn down’ function by simply reducing the static pressure in times of lower occupancy. In summary, during the building concept design stage the chilled beams can be selected to provide future flexibility to enable the end user to reconfigure the occupied space to cater for changes in use. Ever more innovative designs, including the use of ground source heat pumps in tandem with chilled beams and radiant chilled ceilings, are improving the sustainability of building services systems by reducing the amount of energy needed to heat or cool water. Water is a great medium for the transportation of heat energy (circa four times better than air given its specific heat capacity) and reduces the amount of refrigerants – a primary source of building-related greenhouse gas emissions.
Installation
Correct installation of chilled beams and/ or chilled ceilings is important to avoid compromising occupancy thermal comfort, performance levels, and ensuring aesthetic requirements are met. Installations should be carried out in accordance with manufacturers’ guidelines. The designer of a chilled ceiling or chilled beam cooling system solutions should
12 BUILDING SERVICES & ENVIRONMENTAL ENGINEER APRIL 2023
be aware of, and take into account, the latest codes and recommendations for pipe-work design. It is advisable to leave any protective covering in place until the last possible moment. This will minimise the risk of dirt and/or dust covering the ceiling/beam and help prevent accidental on-site damage. All coverings should be removed before commissioning.
Cost and performance
Alongside the initial capital cost of the ventilation, heating and cooling system, whole-life considerations such as on-going maintenance and energy costs must also be considered. Because of the low maintenance
requirements and energy consumption associated with chilled beams and/or chilled ceilings solutions when compared to other systems, the whole life cycle costs for chilled beams and/or chilled ceilings are often lower than other cooling systems. However, it is recommended that individual
project life cycle analysis is undertaken because of the huge variations in building design. Special care should be taken to accountfor the low maintenance, reduced energy consumption and long life expectancy (30 years+) when undertaking cost comparison with other systems. Other systems may have an initial lower capital expenditure but higher maintenance cost and lower life expectancy and require more energy consumption. Chilled beams and/or chilled ceilings can be a very cost effective solution, the more years they are in operation the more cost effective they become.
The technology has still not achieved its full potential and is often overlooked for projects where it would be the best suitable system. This is largely due to a lack of knowledge and understanding across the building sector and has flagged up the need for a better flow of information between suppliers, consulting engineers, architects and contractors.
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