I worked for Johnson Controls for 10 years, and this type of terminololgy is central to what controls companies put together. I also worked for 1 year as a digital controls installer with another company.

Basically, it costs x dollars to heat or cool, light, and control a building. Largely these are energy costs, but there is a lot more automation that can be accomplished from security systems (door control systems) to point trending and data capture. Intelligent lighting systems use sensors to detect activity, but also operate from a schedule. Air handling systems are scheduled but can be commanded from a a central workstation. Boiler and chiller plants become automated, and technologies such as ice storage for cooling, can be implemented to help displace peak energy consumption from energy companies peak energy costs. (the cost of energy changes through the day, and most office buildings are unoccupied at night, so if you can store energy from night, and use it during the day, your costs will be less, because daytime energy is more expensive)

The building 'envelope' is a perspective on energy management that looks at the total energy inputs and outputs, including infrared sensing of the exterior of the building. It looks at myriad methods and technologies to control and or reduce the losses, and increase efficiencies through automation. There is no simple definition, as it can even included planned service agreements for equipment maintenance, and lighting ballast replacements and light bulb replacements. Treatments can be added to windows to decrease heat loss if heating costs are high, or addtional ventilation if cooling costs are high.

Building management systems have been around since the pneumatic systems were first installed in the the sixties. The founder of Johnson Controls was Professor S. Johnson, and was the inventor of the Automatic Temperature Control Thermostat, in 1895 or so. 'Intelligent' really means that the equipment is electrically controlled, scheduled and able to respond to users presence. Also that motors for pumps and fans have variable frequency drives, which can throttle output of the controlled device to match demand, and therefore optimize the energy usage to actual demand.

Energy Management Systems, or Facility Management systems, or Building Management systems, whatever the individual proprietary companies call their product line, are often accompanied with greener initiatives for conservation and recycling for the building tenants and customers, so the overall effect is a significant savings, and sometimes even tax incentives by the government.

The central workstations have bound graphic systems with live data mapped to the schematic pictorial graphics from throughout the building. This can included fan and pump statuses, various temperatures, pressures, humidities, lighting zones, door status, etc. As mentioned, the systems can also run trends and data reports on any selected device. as suggested earlier, occupancy control is central, and large air handling systems are strategized to the occupancy plan, and Variable air volume systems give metered control to conditioned air production, tailord to actual usage and user preference, instead of a 'large plant' strategy, which is very inefficient. There are dozens of strategies for air, heating and cooling delivery systems, and there is a significant amount of science involved, and increasingly so, more research, as the cost of energy rises.

Chris

below: an HVAC plan on a floor, showing ductwork and zones, and vav boxes.

There are 56 floors in 3 towers in this complex in Ottawa.

Below: a water filtration plant for a semiconductor plant

below: a large heating, cooling, and cooling tower plant system