Buildings and their power and cooling systems are built to last for decades. However, they must respond to market conditions on an hourly basis to operate efficiently. This requires not only selecting the right equipment, but designing a strategy for it to operate at the lowest possible cost. Fuel prices can double in a month. Electricity prices can have even wider swings in a single day, and prices are highest just when air conditioning is most in demand. Further complicating the issue: A building owner can earn money by agreeing to participate in a utility's demand-response (DR) program, in which he or she agrees to curtail electricity use on the demand of the utility or wholesaler....