As urban population density increases, larger buildings are becoming increasingly commonplace, and controlling their internal environment accurately is a challenge for designers and operations staff alike. In addition, rising environmental concerns and tightening regulations have made minimizing resources used to heat and cool buildings a serious consideration.
The business of building automation integrates heating, ventilation, air conditioning and refrigeration (HVACR), with control interfaces and monitoring systems – all with the help of pressure sensors.
HVACR involves complex control algorithms that operate using feedback obtained throughout the system from a range of sensors – checking temperatures around the building and pipework, as well as overall air circulation.
- Monitoring air filters
The air filter is a critical part of any HVAC system, and it needs to operate efficiently at all times. By using a differential pressure sensor to measure the pressure on both sides of the filter, the building automation system can monitor the airflow at all times.
- Minimizing fan power use
The flow of air in an HVAC system needs to be kept within specific parameters in order to maintain a safe and comfortable living or working environment. Fans force the air through ducts in the system to keep it circulating. A network of differential pressure sensors fitted across the air ducts monitors how the air is flowing throughout and allows the system to regulate each fan’s speed and keep energy costs to a minimum.
- Maintaining relative duct pressure levels
Differential pressure sensors are also used to measure the relative pressure differences between duct air and room air. Air pressure differences can cause various issues in a building, normally attributed to either a positive or negative air pressure difference. For example, a negative air pressure in one part of a building will cause air currents, as the relatively higher pressures find their way into the low pressure areas. An imbalance can lead to doors or windows being difficult to open or close, or a loss of heated/ cooled air which leads to higher energy costs.
- Improving heat exchange efficiency
Building management, control and automation systems are able to control the temperature and humidity of a room thanks to the feedback their sensors provide. Of particular importance are pressure sensors that measure the relative air pressure in a room, which is generally normalized to 1 atmosphere (ATM). Using a pressure sensor to monitor the air pressure in a room over time can determine whether there are sealant leaks around doors and windows, which would lead to heat (energy) losses.
- Monitoring variable air volume heating systems
Ventilation is an important aspect of HVAC systems, which involves closely monitoring and controlling the volume of air flowing into a room. If the heating system uses a Variable Air Volume (VAV) configuration (as opposed to a Constant Air Volume, or CAV system) the temperature is maintained by varying the volume of air flowing into the room, rather than the temperature of the air.
- Automated safety systems
Building management controllers can use pressure sensors to directly control aspects of the HVAC system, often in the form of a differential pressure sensor that operates as a switch. This allows the system to automatically turn devices off or on when it measures a pressure difference that is under or over set limits, potentially preventing wider damage to the system or sudden environmental changes within the building.