ACHRNEWS

Trends In Coils, Condensing Units

June 1, 2009

Microchannels. Modularization. Ruggedness. These are some of the terms being applied to coil and condensing technology. The following are some of the most recent trends based on information supplied to The NEWS.

ELEMENTARY MICROCHANNEL

Microchannel technology was offered as part of a solution to maintain proper refrigeration temperatures while still lowering costs for a food service operation at Kearney Elementary School in Missouri.

Reliable Mechanical Services (RMS), a commercial and residential HVACR contractor in the Kansas City, Mo., area, was called in because, according to RMS President Brandon Narron, “Without proper refrigeration, the school’s cafeteria can’t operate, and that is not an option.”

Cost considerations were another factor. “I suggested that Kearney Elementary consider upgrading their old condensing unit with a new Bohn condensing unit [manufactured by Heatcraft Refrigeration Products] because it can offer excellent energy savings,” said Narron. “And we knew the equipment would keep food at the required temperature. That’s a critical issue for a school cafeteria.”

Bohn Refrigeration specialist Pat Thomas recommended installing a condensing unit with microchannel coil technology for increased heat transfer capabilities and reduced refrigerant charges.

He noted that RMS “was very willing to install the microchannel unit after seeing the benefits of using a smaller unit with less refrigerant charge. Also, the all-aluminum construction provides excellent protection against corrosion and refrigerant leaks.”

“The reduced refrigerant charge was definitely the selling point,” Narron agreed. “We also appreciated that the equipment was so lightweight, it made it easier to move the equipment into position.”

COOL COILS

An approach being introduced to an increasing number of commercial buildings involves remoting all refrigeration units (including those in reach-ins, walk-ins and ice machines) to a single modular system. According to Master-Bilt, the approach allows for the removal of heat produced by multiple refrigeration systems (MRS) in kitchen or retail areas, and reduce the air conditioning load.

Each system is composed of individual modules, including a compressor and condenser coils, the company said. The modular condensing coils are designed so that each refrigeration module uses an individual coil section. If necessary, a coil section can be replaced without shutting down the system, the company said. The stacked condensers are sized for 110°F.

In the latest configuration, two fans per condenser row allow for increased airflow across the condenser, with the horizontal airflow providing the ventilation.

“The improved space-saving system has increased refrigeration module-to-frame ratio, which means more refrigeration systems can be installed on each frame,” the company said. The systems are prepiped to a central location, with a single roof penetration point reducing installation costs and chances of roof leakage, the company said. The prepiping is done to an internal pitch pocket to safeguard against roof leaks.

Among locations for the Copeland Scroll® outdoor condensing unit are near outdoor patios at restaurants, because the quiet operation is said not to disturb customers.

FOODSERVICE SOLUTION

Foodservice operators are looking for ways to reduce maintenance and energy costs while maintaining food quality levels that ensure customers remain loyal and satisfied with the value of the service provided.

To address these specific needs, Emerson Climate Technologies designed the Copeland Scroll® outdoor condensing unit. Through the integration of three technologies - the Copeland Scroll compressor, variable-speed PSC fan motor and Copeland PerformanceAlert™ diagnostics - a solution was achieved for the foodservice industry. The condensing unit delivers up to a 20 percent reduction in energy usage, as well as a significant reduction in sound, the company said.

For the service technician, the product was designed with diagnostic controls as well as compressor and system protection to increase equipment reliability and simplify system troubleshooting for both skilled and newly trained technicians. In addition, the unit’s lighter weight and slim profile aid the installation process and provide location options not previously available, the manufacturer said.

In one particular application, the unit was installed outside of a restaurant on the customer’s patio. The condensing unit’s quiet operation makes it hardly noticeable to customers, according to reports. Energy usage has also been reduced and during a rough winter that was worse than normal, the condensing unit was said to have performed well.

BY THE SEA

Coils that have held up well in coastal areas, where they are subjected to a harsh marine environment of blowing sand and salt spray, are the Spine Fin™ all-aluminum outdoor coils from Trane. The patented process was developed to strengthen the reliability of the company’s outdoor coils over the standard plate-fin type, the company said.

Heat transfer is one of the most important factors in achieving cooling efficiencies, officials said. The design provides greater heat-exchanging capabilities (meaning higher efficiencies) and is more resistant to corrosion than a traditional copper-aluminum coil, the company said.

It incorporates thousands of tiny fins bonded to continuous aluminum refrigerant tubing (the spine) for a more efficient coil. By using aluminum in the tubes, as well as the fins, it has more corrosion resistance and is a longer-lasting outdoor coil.

Features include:

• A configuration that requires no end turns.

• Internal grooves inside that stir the refrigerant, enhancing heat transfer.

• Patented transition joints that help reduce leaks (leak rate of less than 0.05 percent on Spine Fin).

• Four-sided configuration that presents a large surface area to the outdoor airstream.

• 90 percent fewer brazed joints.

Publication date: 06/01/2009