Compressors offer new twist to air conditioning - accessory products

Diesel Progress North American Edition, Oct, 2003

Keeping people and spaces cool is a significant concern in heavyduty trucks, recreational vehicles and marine vessels. While engine driven compressors have historically been used to meet the demand, it is most often at the cost of increased vehicle idling. Along with the expense of fuel--which can be up to $4000 per year in some cases--idling also has negative effects in terms of emissions and engine wear.

In an effort to rake the engine--and particularly engine idling--out of the equation, Masterflux, a division of Tecumseh Products Co., has developed a d.c.-powered, variable speed compressor designed to accommodate a range of cooling and refrigeration needs. Available in two models and multiple capacities, the Masterflux compressors are compact, hermetically sealed units that serve as the heart of the cooling system.

"This is a brand new product," said Jim Abela, sales manager for Masterflux. "There are a lot of niche markets that can benefit from this technology and our growing customer base reflects this.

"We sell quite a few into the telecommunications industry for electronics cooling. There are a couple in military applications--one company has built a collapsible mobile refrigeration unit. Another application is small aircraft air conditioning and it's being used for scientific air sampling equipment, some medical equipment and blood cooling devices. There is also a company in Europe prototyping some bus driver cab air conditioning units.

"In trucks, the benefits are find savings and machinery savings, particularly the engine. Them is also less noise, as these can be run off a battery bank."

The Masterflux compressors were originally developed in the mid-1990s by a California company and the product was acquired by Tecumseh in late 2001. The two models of compressors--dubbed the Alpine and the Sierra--each feature the same basic design, which consists of an electric motor section and compressor. The top-mounted electric motor is connected by a shaft to a rolling piston at the base of the compressor. When energized, the rolling piston compresses the refrigerant--the units are compatible with all CFC, HCFC, HFC and hydrocarbon refrigerants. The unit can operate at voltages from 12 to 700 Vd.c. and the Masterflux BLDC controller allows for variable speed operation.

"An a.c. version of compressor is also available and is used primarily in the mobile home and RV market for rooftop air conditioning, " said Abela. "It holds up to vibration very well. Both the d.c. and a.c. versions of the Sierra and Alpine are rotary, or "rolling piston" type compressors. They are very compatible with high speed operation and give you exceptionally high capacity in a very compact size."

The Sierra, at 9 lb., 11 oz., 5.70 in. high and with a 4.6 in. outside diameter, is the smaller of the two units and has a full volumetric flow of 1 cfm. The Alpine is 10.1 in. high, has an outside diameter of 5 in. and weighs 18 lb., 6 oz. Volumetric flow at full speed is 2.9 cfm.

Along with the military and electronics cooling applications, the Masterflux compressors are also part of the NITE (No-Idle Thermal Environment) system sold by Bergstrom Inc., Rockford, Ill. The NITE system is designed to provide complete thermal management in heavy-duty truck cabs and sleepers with no engine idling and incorporates an AC system, a heating system, a rechargeable power source and a control system into a single 210 lb. package. *

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