"The 12-ton unit is great, because it allows you to duct supply and return air long distances. We have large fan motors on the unit, so you can put over 100 feet of duct on the supply and return ports. This means you can put the unit relatively far away from the room or the application and still provide cool air and pull heat out of the space," said Garth Tagge, vice president, Spot Coolers.

In this particular application, the units were not that far away from the studio, so the supply air was ducted into the room and the return air was pulled out of the room by cutting holes in the dividing wall. Being a television studio set, it was necessary to keep equipment noise to a minimum. The wall helped mask some of the sound, but more needed to be done.

A 12-ton unit provides 4,800 cfm of air coming out of two 14-inch supply hoses. Each supply hose delivers 2,400 cfm of cool air.

"They had to slow the air down to get rid of the air noise," said Tagge. "To do that, they took the supply hoses and split them off so they had two 14-inch hoses coming off each 14-inch supply. Then they put in a tee, diverting the air into two hoses. That slowed the air down, which reduced any noise from the airflow."

This particular job was a challenge because the building was older, and there was not much room to stage the equipment. Another challenge was how to handle the heat rejection. An abandoned elevator shaft provided the solution. The shaft wasn't operational and exhausted at the roof. It was a good size, so the heat didn't back up into the working space, and it was possible to reject the heat without incident.

Usually in a temporary situation, such as a 12-ton unit in an office building, the only place to duct the hot air is into a stairwell or a mechanical room. Getting rid of the heat can be a problem, and the bigger the unit, the more heat is being transferred, and the bigger the problem can become. In this case, it was convenient to use the shaft, which was only 50 feet away from the equipment. The condensate created by the equipment was simply pumped to a sink.

Planned Maintenance

This particular building had numerous places in which chilled water was required to feed air conditioners in computer rooms and equipment rooms. The four-day planned shutdown meant that portable cooling had to be brought in to keep these sensitive areas at the correct temperature.

The property manager talked with the tenants several months prior to the shutdown and asked for a list of areas that needed to be cooled. Once identified, Spot Coolers was contacted to assess each situation and determine the proper type and capacity unit to be used. They came in the day before the shutdown, staged the equipment, which took a full day, and made sure that heat rejection could be accomplished.

This particular job required 70 portable cooling units, each with a capacity of 1 to 1.5 tons. In order to set up the equipment, Spot Coolers brought in ceiling kits, which are 2-foot by 2-foot metal panels with hoses coming off them. The 12-inch hose drops down onto a flange on the portable equipment, and the hot air is channeled up through that hose up into the ceiling.

A ceiling tile can be pushed aside and replaced by the ceiling kit panel. Once the panel is dropped in, the hose coming off the panel drops onto the equipment. Condensate goes into buckets, which the property manager's staff had to empty several times during the shutdown.

This particular job involved a property management company, but Tagge noted that more often than not, Spot Coolers deals directly with the contractor.

"Most contractors are very knowledgeable about portable air conditioning," he said. "We are often brought in to help size the job and determine which equipment is going to be used. We have all kinds of portable air conditioning, including air cooled, water cooled, split systems, and heat pumps."

Many times the contractor will take care of staging the equipment, especially if it might get in the way of his crew if staged prior to the day work is done. Otherwise, Spot Coolers takes care of it.

"We make sure our equipment is as unobtrusive as it can be," said Tagge. "We also make sure the fleet of air conditioners is in good shape, clean, and operational."

The result is great-looking equipment that also performs well, which is important even in a temporary situation.

For more information, contact Garth Tagge at 800-367-8675 or visit www.spot-coolers.com.

Publication date: 02/09/2004