Air-Cooled Chiller Makes Its American Debut
However, Carrier waited until this year to roll out the Aquasnap line in North America. The lucky recipient of the first Aquasnap here is a Johnson Controls facility in Florida. So with camera crews rolling and everyone involved waiting in anticipation, the first Aquasnap was successfully placed on North American soil.
What’s New and Different
Carrier is particularly excited about its new air-cooled chillers, because they feature a compact, all-in-one hydronic package design. The Aquasnap’s integrated pump package with strainer, blow-down valve, expansion tank, pressure gauges, electric heater for freeze protection, drain, vent, flow switch, balancing valve, and storage tank are pre-built into the unit. Regardless of the application, the company says its chiller can be installed quickly and easily on the ground or on the roof.Having everything included in one neat package means there is no need to purchase the components individually. The fully integrated and preassembled hydronics makes installation simple, with a single connection for the water piping and a single connection for the power.
Customers should also appreciate the low operating costs that Aquasnap can provide. With a standard year-round operation from -20°F (with optional heater) to 125°F, Aquasnap’s high efficiency ratings are designed to keep costs down. In fact, the company said its chillers achieve full-load EER up to 10.1 and part-load ratings as high as 14.3 EER. All units exceed ASHRAE 90.1 standards.
The chillers use high-efficiency scroll compressors, operated in tandem for greater efficiency at part-load capacity. Highly stable elastomeric gaskets are designed to help maintain compressor efficiency for many years. There are 11 models of Aquasnap chillers available, ranging from 10 to 55 nominal tons.
Better IAQ Required
But enough kicking the tires and looking under the hood. The reason why Aquasnap was first installed in Jacksonville, FL, was the fact that Johnson Controls was having an indoor air quality (IAQ) problem in its facility, which was built in 1983. The combination office building (6,090 sq ft) and warehouse (2,150 sq ft) had too much humidity creeping in through leaky windows. Mold and mildew started to appear between the wallpaper and the drywall.An on-site IAQ specialist monitored the building and determined that the severity of the IAQ problem meant that windows needed to be replaced, drywall needed to be ripped out, and a new air conditioning system had to be installed.
Enter Buddy Doll, Carrier Enterprise’s sales manager for Florida. “Because of the IAQ problems, Johnson Controls decided they wanted to go with a chilled water system, because chilled water gives you inherently better humidity control and temperature control,” says Doll.
What was a little tricky about this installation is that an existing split system served the building. A condensing unit sat on a concrete pad about 20 ft from the building, and the unit was piped to an indoor air-handling unit with a dx (direct expansion) coil.
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“We weren’t sure with the piping being that close whether or not chilled water would work. Any time you have an air-handling unit right next to a chiller, you have the potential for it being a close-coupled system. And if you don’t have enough water volume in the system, you could be banging compressors on and off, and it’ll adversely affect the life of the chiller,” notes Doll.
Some at Johnson Controls feared that going to a chilled water system meant that space had to be made for a pump in the mechanical room, which had no room for anything else. However, Aquasnap doesn’t need the space, because it comes with the pump already installed. In fact, that’s the main reason why Johnson Controls decided to go with Carrier. And there ended up being enough water volume after all, so that wasn’t a problem either.
The new, 20-ton Aquasnap chiller was hauled in on a Friday and the installation was completed by Sunday, much to the amazement of critics who were sure it couldn’t happen that quickly. “A lot of people were saying there was no way this could happen, but in roughly 24 hours we had the condensing unit taken out and the chilled water piped up and the chiller was running. It went really well,” says Doll.
In addition to the new chiller being installed, a new coil was put in the air handler, and Johnson Controls took the opportunity to install one of its “Metasys” building automation systems (bas). The building had no prior bas, and in addition to giving operators tighter control of building systems, the installation gives Johnson Controls an opportunity to take customers to see a Metasys system in action.
Taking customers through to see the bas has advantages for Carrier as well — people see the Aquasnap and are interested. In fact, two additional customers have purchased Aquasnaps as a result of the Johnson Controls installation.
With the new chiller in place and all renovations complete, the Johnson Controls facility is finally free of IAQ problems and has attained a higher level of comfort. And occupants received an additional surprise — they were amazed at how quiet the Aquasnap is. That’s due to the “AeroAcoustic” fan and low sound operating mode, which reduces sound output by nine decibels.
“This unit is so close to the building, and it’s right next to the windows. They were really thrilled the unit was so quiet. Sound considerations were much nicer than they anticipated,” says Doll.
Sounds like a happy ending all the way around.
Publication date: 07/09/2001
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