When it comes to conserving energy and controlling costs, high velocity air conditioning systems can be a highly economical alternative to traditional air conditioning systems. One charter school in the city of Pomona, California recently learned that lesson.
The city of Pomona California, which was first incorporated in the late 1800s, has gone through a revitalization of sorts in the past several years, transforming part of the city into the Pomona Arts Colony, one of Southern California’s leading community arts clusters.
The colony features many public and private art galleries representing some 1,500 artists, numerous arts-related businesses such as graphic arts firms, as well as architecture and entertainment companies, and is home to nearly 200 individual artists – many of whom live and work in lofts developed in originally commercial buildings.
The Pomona Arts Colony is also home to the School of Arts & Enterprise, a state-certified, public, charter high school that combines a traditional college preparatory curriculum with a focus on the arts and arts businesses. The school is located in the heart of the Arts Colony, and housed in a recently renovated 15,000 sq. ft., two story, concrete and glass building originally built in 1962. The building was originally administration offices for a local university, and features many open areas, drop ceilings, a ground-to-roof glass wall on one side of the building, and is home to classrooms, a 99 seat theatre, conference rooms, a computer laboratory, an art gallery, and administration offices for the school.
“When the School of Arts & Enterprise was being renovated,” said Kevin Bock, president of AmeriAir Heating and Air Conditioning, Inc., of Rancho Cucamonga, Calif., a residential and commercial HVAC company that serves Southern California, “we were hired to address the air conditioning situation. The building posed some challenges because the roof was structural concrete so we could not penetrate the roof with duct work, and therefore we could not use package units for the installation.”
In Southern California the need for air conditioning is simply a matter of fact, and given today’s rapidly increasing energy costs, particularly in California, many building owners want the most energy efficient systems available, as well as a system that offers zone cooling.
“When we were hired, the building was being served by a single aging 50 ton air-conditioning unit that was housed on the roof of the building. The air was either on or off in the entire building, so there was no zone control, and due to the building’s open architecture design and the inefficiencies of the original air conditioning system, some areas just would not cool down sufficiently. In addition there were constant mechanical problems with the AC unit, and the owner was spending more money than necessary to air condition the facility,” said Bock.
Bock’s first recommendation was to eliminate the old central air conditioning system and replace it with a more efficient high velocity air conditioning system manufactured by SpacePak of Westfield, Mass.
“We replaced 50 tons of conventional air-conditioning, with several small SpacePak units totaling 36 tons,” said Bock. “It was a reduction of 168,000 Btu/hr. of air-conditioning capacity and not only where we able to accomplish the goal of efficiently cooling the space, but we saved the school about $35,000 in installation cost, and in the process provided added efficiency, and the ability to cool specific spaces in the facility without having to cool the entire building. In addition, because the SpacePak system removes about 30 percent more humidity than conventional air-conditioning, the system can be set at a higher temperature and still keep the students and teachers comfortable.”
Bock first learned about SpacePak from ACH Supply, a distributor located in Irwindale, Calif. ACH had worked with Bock and his crew by providing comprehensive product training and support services. “Our goal is to provide all the technical and product information that we can to ensure that the contractors are both knowledgeable and confident when it comes to installing SpacePak systems,” said Craig Heald, sales manager for ACH Supply. “And we are very confident in AmeriAir’s installation abilities.” In addition to providing training, ACH Supply also provided Bock with installation materials to support the SpacePak sale.
As with many of the buildings in the Arts Center, the School of Arts & Enterprise has an open floor plan. As such, the installation required that the vast majority of the new air conditioning duct work would be exposed. To make matters more complicated, the project had to be completed quickly and it could not be disruptive to the students. It took Bock and his crew of four three weeks to remove the old system and most of the existing duct work, and install the new system.
“We had to work some odd hours to accommodate the school’s schedule,” said Bock. “Lots of the installation was had to be done before school or after hours. We also tried to be as economical as possible, by leaving some of the existing duct work which we converted into returns for the new SpacePak system,” he said. “One of the nice things about this type of high velocity system is that the installation is very flexible and does not involve lots of construction or mess and does not disrupt the existing walls, floors or ceilings.”
The new system includes nine individual fan-coil units -- three 5-ton units, three 4-ton units and three 3-ton units -- all of which are housed in the building’s attic. Each fan coil is relatively small in size, the largest of which is approximately 14-in. (h) x 43-in. (w) x 30-in. (l) so there was ample space to install multiple units. From the individual fan coil units, the system includes a nine-inch wide insulated plenum duct which was installed throughout the building, mostly at ceiling height. Because the building only has drop ceilings on the first level, much of the space did not require use of the standard two-inch air supply lines, Bock and his crew cut holes strategically in the plenum duct lines. Each unit is also attached to a Trane condensing unit installed on the building’s roof.
This air distribution system is based on a principle known as aspiration, where the air is injected into the room at a much higher velocity (i.e. 1600 – 2000 ft./min.) than with conventional air conditioning systems (i.e. 300 – 400 ft./min.). As a result, the system provides complete air circulation throughout the space, eliminating the typical 2-3 degree temperature stratification between the floor and ceiling.
“The plenum lines, rather than a series of individual supply lines, provide a good percentage of the cooled air throughout the school,” said Bock. “We designed and cut a series of holes in the plenum lines to direct the cooled air where we needed it to go. The result is an efficient air conditioning system that can cool the usable parts of the entire building. In addition, the School can now monitor different areas throughout the building and each classroom is on its own system for maximum flexibility and comfort.”
Take the computer laboratory as an example. The large room required nearly 175-feet of nine-round plenum trunk line just to reach the room on the first floor. The space, which is warmer than many other areas due to all the computer equipment, is cooled by one of the 3-ton SpacePak units.
“The first floor rooms have suspended ceilings. In those rooms, we ran the standard insulated two-inch flexible tubing from the plenum line directly to ceiling outlet terminations in those rooms. In the end, the system is very easy to install and did not require any significant renovation in the building.”
“Overall we are very happy with the SpacePak system,” said Cathy Tessier, the building owner. “We used to get constant complaints about the air conditioning system, but we have not had any complaints, which I attribute to the new system and our ability now to cool specific rooms.”
When all was said and done, Bock and his crew installed nearly 1,000 feet of trunk line plenum throughout the facility. “We completed the project on time and on budget,” said Bock, assuring his team an A+ in the installation.