Installing energy efficient boilers, or even the latest renewable and low carbon heating technologies, can play an important role in meeting carbon reduction targets and, of course, in lowering the end users energy costs. However, it is also crucial to look at how heat can actually be retained within a building. If a building has its doors left open for much of the day, or the doors are regularly being opened and closed, air curtains can provide an effective solution for retaining warm air.
Air curtains are specifically designed to minimise the amount of cold air entering a building, while keeping the warm air inside. If an air curtain is not fitted, heat will naturally escape from the door as soon as it is opened. Due to natural convection, warm air will spill out of the top, being replaced by cold air coming in at the bottom.
Disrupting and minimising this flow, air curtains provide a continuous stream of air circulated across a doorway serving a conditioned space. The cold air coming in is then conditioned, with the warm air being obtained from various sources, such as direct electric heating and low, medium or high pressure hot water.
The energy saving benefits of air curtains have been well documented and can be significant. It is estimated that an average double doorway could be losing as much as 32kW of energy every hour and, at 10p per kWh, this can equate up to £7,000 worth of energy each year. By installing an air curtain, wastage can be cut by up to 70%.
However, in order to ensure that the full energy efficiency benefits of air curtains are realised, it is essential that they are designed, sized and installed correctly. In the past, a lack of understanding about air curtains and how they work has resulted in some poor installations, where energy efficiency has not been achieved. In fact, a poorly specified, installed and controlled air curtain can have a detrimental effect, making the total energy consumption worse than it would be if one was not fitted at all.
There are a number of steps that can be taken to ensure that this is not the case. For example, an air curtain must be installed inside the doorway, as close to the opening as possible. It must be just wider than the doorway opening with an overlap at both sides. It is also important to note that air curtains should be specified on the size of the door, not the kW output.
The design of the air curtain must be able to discharge air across the whole height and width of the opening, at a suitable supply air temperature, and the heat output of the air curtain must be sufficient to temper the volume of air coming in at the entrance. It is important to ensure that the jet stream is right; it wont be effective if it has too little velocity or is too powerful.
Installing an air curtain doesnt mean that the overall design of a building has to be compromised. For example, while brushed stainless steel is often a popular choice, those looking for added aesthetic appeal can opt to have the air curtain powder painted. With a vast choice of colours available, this allows the customer to easily blend the air curtain into the entrance area, or to enable them to fit in with the corporate identity. There are also stylishly designed solutions available for premises with glazed frontages where there isnt a solid structure to hang an air curtain on in the conventional way.
A property with a correctly installed air curtain can see huge energy efficiency benefits. Not only does this help to reduce energy bills for the end user, it also helps to reduce the carbon footprint of the building as a whole. Therefore, the installation of an air curtain is a particularly useful addition for architects and developers to take into account when working on new projects, when they can fit seamlessly into the design of the property.