HVAC and BEMS

The EMF that opposes the normal flow of current in a circuit.  Also known as Counter Electromotive Force (CEMF).

This is the refrigerant pressure in the low side of the system also called low side pressure or suction pressure.

BACnet is an ASHRAE Building Automation and Control networking protocol, designed specifically to meet the communication needs of building automation and control systems for applications such as heating, ventilating, and air-conditioning control, lighting control, access control, and fire detection systems and their associated equipment.  The BACnet protocol provides mechanisms by which computerised building automation devices can exchange information, regardless of the particular building service they perform.  As a result, the BACnet protocol may be used by head-end workstations, general-purpose direct digital controllers, and application specific or unitary controllers with equal effect.

A BBMD is used to distribute BACnet broadcast messages throughout a BACnet/IP network consisting of interconnected TCP/IP sub-networks.  A BBMD forwards BACnet/IP broadcast messages sent by devices connected to its subnet peer BBMDs.  On arrival at a destination BBMD, the message is then re-broadcast on that subnet.  BACnet/IP broadcast messages are also sent to registered BACnet/IP Foreign Devices.

When both the inside and outside pressure of a container equal each other.

Used to measure atmospheric pressure.

Also called a draft damper, is a device used to regulate airflow and control draft in heating systems, particularly in boilers and HVAC systems.

A corrugated cylindrical container which moves with a pressure change.

A temperature regulating or indicating device which works on the principal that two (2) dissimilar metals with unequal expansion rates, welded together and will bend as their temperature changes.

A low-temperature evaporator that uses a fan to force air rapidly over an evaporator service.