Integrated systems demand control technology

The peak electrical demand of office building VAV systems will be reduced by about 1.2 Kw/1000 Ft2 by employing an Integrated Systems Demand Control Technology (ISDCT) sequence to reduce peak intake flow by about 56%.Supply, return, and exhaust fan energy decreases with reduced airflows and pressures; and chiller system energy is saved by reduced cooling coil loads.The ISDCT sequence continuously computes zone contaminant concentrations allowing compliance with reference standards. The office computer system identifies active personal computers and transfer this and manually inputted zone occupancy data to the building automation system-eliminating the need for CO2 sensors.All buildings require dynamic building pressurization control to adjust for substantial wind and stack boundary conditions-which can actually reverse intake and exhaust flows. Building differential pressure measurement should be used to calibrate and dynamically reset the building pressurization flow setpoint.Pressurization flow accuracy was evaluated using 2% and 6% repeatable airflow sensors; the 2% sensors allowed 10 steps of control near minimum pressurization versus 3 steps for the 6% sensor. Given a minimum controllable building pressure setpoint of about 0.0005 inches water column, a sensor repeatability of 0.00005 inches water column will provide 10 steps of control.