With nearly 5,000 employees and annual operating revenues in excess of $3.3 billion, Alliant Energy Corp. provides regulated electric and natural-gas service to approximately 1.4 million customers in Iowa, Wisconsin, and Minnesota. At its headquarters in Madison, Wis., seven air handlers utilizing steam humidifiers are used in part to keep static electricity down during winter. The decision was made to upgrade the humidification system to a more energy-efficient technology.
Facilities manager Gordon Kensgaard contacted The Best Group for assistance in selecting a new humidification system. The Best Group, which works with steam- and adiabatic-humidification systems, recommended Alliant investigate Mee Fog high-pressure systems, which atomize water into billions of super-fine droplets for quick absorption using 1/100 of the energy required by electric steam humidifiers.
Two high-pressure Mee Fog pump systems provide 1,000-psi water to nozzle headers via staging solenoids. Both pump systems have a dedicated water-treatment system to remove dissolved solids before water is introduced into an air stream. The capacity of both systems is controlled by the building control system through the staging solenoids. The building-automation system determines how many nozzles are needed to match the humidity load under all weather conditions and energizes the correct sequence of high-pressure solenoids.
Humidity is introduced into each air handler between the pre-heat coil and cooling coil. Any moisture not absorbed in that section is collected on a droplet filter and drained.
The installed capacity of the seven air handlers is 2,832 lb per hour. The electrical load is 4.5 kw. Annual energy savings, as compared with electric steam-generating humidifiers, are in excess of $300,000, with a further reduction of $15,000 in annual maintenance costs.
Information and photographs courtesy of Mee Industries Inc.
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