At this point, there are on/off controls in place for virtually every major item of the HVAC system. It is now possible to use the EMS to great advantage by monitoring the electrical demand and turning equipment on and off to keep the peak demand as low as possible. The demand control system automatically monitors power demand and shuts off previously determined secondary loads to reduce the peak to a specific level.
This demand-limiting philosophy is implemented by turning off pieces of equipment as the electrical use approaches the peak. The software, already programmed with a prioritized list of items to be turned off, simply follows the list until the energy-use curve is leveled off, and the peak load passes. Clever programmers (or an artificial intelligence algorithm) can make use of the building mass to provide some thermal momentum during these periods, extracting or rejecting heat to the building while the HVAC is turned off, to always maintain a comfortable environment, even when equipment is cycled off for 15 to 30 min.
__________
Excerpt from Energy Conservation Projects.