The design of the equipment that is used to control and integrate door air curtains in automated systems for buildings is of central importance. The process measuring and control units supplied by manufacturers very often constitutes the solution that offers the best price-performance ratios for customers. There are a few points that require consideration here:
1. Operation of an air curtain
Air curtains should be implemented in such a way that they are extremely simple and easy to understand and use as they are often operated by the responsible personnel on site.
Depending on the concept, it is frequently necessary – besides the option of setting fan speeds – to enable users to switch from summer to winter operation and vice versa by pressing a further key. Summer operation that doesn't use the units’ heating systems then serves to keep the warm air out.
2. Activation through doors or gates
Motion detectors represent a good option for the timely activation of air curtains. Air curtains may alternatively be set to run at basic speeds during times with high visitor frequencies and then run at higher speeds when the doors are operated.
3. Multiple benefits of air-curtain systems: heating in night mode
Air curtains in entrance areas with heavy internal usage are particularly able to assist heating at night by using an integrated room temperature control to reduce the temperature to a lower set point during the night only.
This enables the air curtain to keep room temperatures at the desired levels during the night and prevent the area from cooling down.
4. Temperature at the air outlet
A controlled discharge temperature is very important for the well-being of visitors. To this end, it’s possible to integrate an electronic discharge-temperature control in conjunction with a continuous valve and supply-air temperature sensor. Such systems generally require more complex controllers as well as greater
parametrisation effort during commissioning. A simple valve with capillary sensor that limits output temperatures may be used as a more cost-effective solution.
5. Filter monitoring
Regular maintenance intervals should be observed to ensure that filters work properly. Electronic systems make it simple to implement a function that uses the number of operating hours to trigger a filter message.
6. Integration into automated systems in buildings
Units should meet these minimum requirements when they are being integrated into building-management systems:
- speed control, ideally using a 0-10 V signal
- potential-free feedback from for in the air-curtain system
- optional: valve control for switching between summer and winter periods
Electronic controls that have been integrated into the units may also be useful when additional functions, such as night heating, are required. It is usually possible to configure and set the parameters for the heating with the help of a gateway; the common practice here is to use connections to Bacnet or MODbus systematist systems are also being employed as are a growing number of KNX gateways.
It often makes sense to select the units along with the control solutions that are available from the manufacturers because, besides the assembly at the factory, they will also be supplied with the factory settings for controlling and transferring the desired data through the interfaces – thus making it possible for customers to benefit from the best possible price-performance ratios.
Further information on control engineering can be found here.