Building automation affects the building occupants’ safety, automates various subsystems’ functionality within the building and can lead to reduced costs. The approach used to reach these goals, however, is varied, and it depends to a great extent on the makeup of a building’s occupants. HVAC systems, security alarms, access control, CCTV, elevator control, intercom systems, parking lot controls and fire systems can all be subsystems that are integrated to develop a totally automated building. The exact automation solution for a given building will be based on the building owners. Automation is in the eyes of the beholder.
Total building automation brings to mind a “smart” building that operates efficiently from an energy management and a people flow standpoint. A “green” building that has reduced power consumption and uses the latest in building materials, technology and automation, also comes to mind. Automated buildings have existed for some time in both Europe and the United States, but recent interest in conservation and increasing energy costs, etc., has renewed a desire to build and operate smart buildings.
This article will describe some of the typical subsystems that compose an automated building. We will assume our subject building has incorporated “green” technologies to reduce power requirements. As you will see, automating a building is a creative endeavor with many possible solutions.
Energy Savings Strategies
Energy can be saved by lowering consumption or turning off equipment and lighting entirely; or, by shifting heavy energy use from the peak demand periods during the day to non-peak demand periods. This can be accomplished with an energy management system that sheds unnecessary loads during periods of peak demand.
To lower energy consumption, lights and heating/cooling (HVAC) can be turned off or significantly reduced when no one is in the area. This can be accomplished with a device that has digital or analog outputs to control fans, chillers, lighting controls, etc. A digital output (D0) is normally a low-current, solid-state switch closure that drives a relay contact, which, in turn, can be used to carry more current when the D0 requires an interconnection directly to an electrical device. For example, the current used to activate an electrical contactor that controls a fan or lighting device would require less current than a switch closure that handles the current that operates the lights. The analog output (A0) is a variable current that can be used to activate a modulating damper or waterline valve for heating or cooling. Energy management systems use D0, Digital Input (DI), A0 and Analog Input (AI) function to control HVAC, lighting and other functions in the building. D0 also exists in a security alarm and/or access control system; therefore, those systems could be used to turn lights or HVAC systems on and off.
Electronic Access Control
The access control function is a vital part of a total building automation concept, by enabling authorized people flow and restricting access to various areas in the building. The way it is used will depend on the owner and the building’s use.
For example, if a single company owns and occupies the building, the company’s culture will dictate the philosophy of access control. In this situation, badge readers on the elevator might be used to gain access to certain floors, or a vestibule area on the executive floor itself might use badge reader control to enable access to the executive floor. In the case where the building has multiple tenants, each different tenant floor or area might incorporate a vestibule area with a receptionist and “after-hour” badge readers. Elevator control (via badge readers) might still be used on certain floors.
A building lobby could use optical turnstiles for faster access of many people, regardless of how many different tenants occupy the building. If the tenant space is designed for other uses than typical office environments, the access control will be much different. The access control philosophy for a retail tenant building, for example, would differ greatly from the office building environment.