Briefs

Theaters, auditoriums, and gymnasiums often provide significant savings due to high occupant density, widely fluctuating occupancy conditions, and the type of systems that typically serve these areas.

Conventional all-air systems are designed to serve the required ventilation loads while meeting the space heating and cooling loads. A DOAS is dedicated to handle the ventilation load.

With a conventional stack gas economizer, the exhaust temperature is maintained at 300ºF or higher to stay above the acid dew point. This limits the ability to improve the system efficiency, usually to around 85%.

Another thing to check when evaluating your boilers is the control band. The control band is essentially the pressures (for steam) or temperatures (for hot water) at which the boiler will kick on and turn off.

A vast majority of boilers, regardless of age, test 80% or better on combustion efficiency! Even some ancient coal boilers that were converted to gas decades ago are typically in the 80% efficiency range.

A rule of thumb is that for every 40F decrease in boiler stack temperature, there is an increase in boiler efficiency of 1%! While this may not sound like a lot, it can translate to big savings and short paybacks.

Many boiler plants are doing just that, continuously dumping hot water down the drain for boiler blowdown. In addition, cold water is often added to the hot blowdown water to meet sewer temperature requirements.