Come on, feel the heat
Radiant heating in non-industrial environments such as schools, health centres, and hospitals, brings a number of operational and energy benefits, as Warwick Taylor of S&P Coil Products explains.
One of the most important questions that a building designer or contractor involved in refurbishment can ask is how to heat the space in the most efficient and economical way possible. After all, with fluctuating (usually rising) energy costs and incentives to lower one's carbon footprint, the best solution can lead to a good deal of money being saved over the long-term and less damage done to the environment.
The type of heating can also affect the comfort and, therefore, the productivity of the people using the building.
Radiant heating is often the unsung hero of this scenario: efficient, controllable, versatile — it can be configured and contoured to fit just about any situation.
Radiant panels heated by low-temperature hot water have the quickest response time of any heating technology, and because panels can be individually controlled for each room they will save energy compared to other systems. When entering a room, the occupant can increase the temperature setting and be comfortable within minutes.
Radiant ceiling panels are widely used in healthcare and education applications for a number of reasons. First, they completely free up the floor and wall space and, to the untrained eye, are merely ceiling tiles. Being part of the ceiling means, assuming the panel has a smooth finish, that the system is very hygienic — obviously beneficial in hospitals.
Radiant ceiling panels also provide even heat distribution and are very controllable, lending themselves to zoning and intermittent usage.
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| Heating for this IT room at Bradford College is provided by high-level radiant heating. |
If the use of a room changes, the tiles can be removed and used elsewhere, with good-quality designs being quite straightforward to install. It is also possible to manufacture bespoke panels for awkwardly shaped spaces.
Additionally, for education applications panels can be perforated for acoustic absorption, and it is possible to integrate other services into the panels.
In some respects using radiant panels on the ceiling goes against the grain. After all heat rises, doesn't it?
Well, no. Heat does not rise, warm air rises. If air is warmed it expands, becomes less dense and is lighter than cooler air, and as a result rises.
Radiant heat is infra-red radiation and warms the floor, furniture and people within the room — not the air.
The actual heating effect is in some respects similar to floor-heating systems — except that it is the surface of the floor, against which the air is in contact, that is warmed. With ceiling panels, the whole floor structure is not heated, and there is a very low inertia — enabling a high degree of controllability.
But the real benefit of using radiant ceiling panels is the raised resultant temperature. We feel temperature from a combination of factors.
One is the temperature of the air in contact with our skin. This is adjusted by the evaporation of moisture from the skin surface, which is our natural way of controlling body temperature.
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| Radiant heating is integrated with the ceiling in this hospital. |
Secondly, we feel the radiant heat acting on us. When the Sun is out you feel much warmer than when the Sun is behind a cloud. The air temperature has not changed, but the amount of radiant heat acting on you has changed. In the context of radiant ceiling panels in a room, the higher level of radiant heat means that you will feel about 3 K warmer than the air temperature would suggest.
In other words, if you are aiming for an internal air temperature of 20°C, using radiant panels can achieve the same resultant temperature when the air is about 17°C.
The internal air temperature being 3 K lower translates to lower heat loss through external walls and, therefore, energy savings of around 15% compared to air heating systems.
Low-temperature hot-water radiant panels are safe where there are fuels, flammable adhesive vapours, or dusty environments. Furthermore, as they are effectively only radiators, they do not require annual maintenance, which can cause disruption — particularly in schools and health settings.
The radiant output of panels is directly related to the surface temperature, and a good panel has the surface temperature very close to the temperature of water in the coil. The European Radiant Panel Manufacturers Association recommends that only panel outputs tested and accredited to EN 14037 should be considered reliable.
A well designed radiant panel will perform without fuss for many years, unobtrusively providing even warmth to keep workers productive, students alert, and patients comfortable — and all this while saving energy and money.
Warwick Taylor is managing director with S&P Coil Products.
