Rating System

LEED BD+C: New Construction

Rating System Version

v2 - LEED 2.1

Inquiry

Our project incorporates microturbines and high efficiency condensing boilers. Modeling the high efficiency boilers is straightforward, but our system and controls are setup to use the microturbine waste heat first (from storage tanks) and then use the high efficiency boilers. Since this can\'t be modeled easily, we plan to perform an Exceptional Calculation Method calculation. The microturbines produce power and waste heat. If we assume that all electricity produced is the same rate as from the utility and the waste heat recovered is used as the first stage of heating at an effective cost less than the boilers, the microturbine recovered energy and energy cost are known and can be calculated as a discrete measure and the cost savings deducted from the DEC\' in the same fashion as renewables. Our procedure to show these savings would be to take the final interactive model (DEC\') heating energy and subtract the recovered microturbine heat, and then apply the condensing boiler efficiency on the remaining heating energy. Then, the heating energy cost savings of the microturbines and condensing boiler would be subtracted from the DEC\' . Please confirm that this approach is acceptable as an Exceptional Calculation. Thank you.