Iowa State University Builds the First Gold LEED Certified Chemistry Laboratory

Cutting Energy Use in Half:

A single custom Phoenix Manufacturing Inc. (PMI) air handler heats and cools the offices and conference rooms on the building’s west side which require a lower percentage of outside air to maintain indoor air quality. The rest of the building, which contains the laboratories, is divided into four quadrants, each with its own 60,000 CFM PMI air handler. The four laboratory AHUs are equipped with plate heat exchangers to recover heat from the laboratory air before it is exhausted from the building.

Henneman Engineering, which designed the air handling system, estimated that by using highly efficient heat exchangers, zone presence sensors and variable air volume systems on the fume hoods, the air handling system would use about half the energy of a base code compliant laboratory building. But, because the laboratories use 100% outside air, greatly increasing the amount of moisture needed, an efficient solution was also needed for humidification.
“In the winter in Iowa, when bringing in the cold air and heating it up, you end up with very dry air,” says Jesson. “The humidity in the building would be 5% without the humidification.”

To achieve a design relative humidity of 30%, the humidification systems needs to operate about 3500 hours per year. The amount of moisture required varies with the outside temperature. When it is below zero, 4600 to 4800 pounds of water per hour are required, but at 45 degrees the need drops to 740 pounds per hour. Using a gas boiler to provide the steam would cost about $137,000 annually. Using a Mee high pressure fogging system would drop the costs to $107,000 per year, a $30,000 savings, even taking into account the additional heating needed to offset the cooling effect of the fog.
“The user required a certain percentage of relative humidity and our research indicated fogging was the most effective way,” says Stephenson. “It is also less troublesome in terms of maintenance.”

Waldinger Corp. installed a single Mee Industries fog humidification system, controlled by the campus’s Johnson Controls Metasys building automation system, to service all five air handlers. The Meefog system uses two 5 hp CAT Pumps, each producing 7 gpm @1000 psi, with an additional pump on standby in case one of the two primary units goes down or is being serviced. Within each of the AHUs is an array of nine ½” stainless steel pipes with a total of 94 fogging nozzles. When there is a need for humidity in one of the quadrants, the appropriate number of solenoid valves open up, sending the water to the number of nozzles required.

Construction on Hach Hall was completed in 2010 and the building was dedicated in October. Stephenson says that he has been in the laboratories with the ventilation hoods running and is satisfied with the way the air handling system works.
“It’s actually quite comfortable,” says Stephenson. “It works well.”