Chillers: The Action is in Portables
While the technical developments in mold chillers this past year could be described as "steady as she goes," more are appearing with scroll compressors that have fewer moving parts, more are using hot...
June 1, 2001 by Bob MacKenzie
While the technical developments in mold chillers this past year could be described as “steady as she goes,” more are appearing with scroll compressors that have fewer moving parts, more are using hot-gas bypass to achieve better temperature control under some operating conditions, and more are using stainless steel plumbing so they will last longer.
But perhaps the most noticeable trend this year is the growth in small “fractional tonnage” portable chillers.
Mini just got smaller
Portable chillers come in basically two cooling-capacity ranges: standard and mini. This year, several manufacturers added new units at the small end of the scale. They are typically in the 1/3 to 1/2 ton range. Some are so small they can sit on a table. For instance, IMS Company released its MicroMax 1/3 ton mold chiller. At 16 in. wide by 20 in. deep and 28 in. high, it can go just about anywhere. And it weighs only 200 lbs, so it can be easily wheeled around the shop floor.
Mokon, Division of Protective Closures Company also makes a fractional-tonnage unit. According to Tom Valentine, Mokon’s sales and marketing vice-president, the Micro Series of the company’s Iceman line “came out of an application that was associated with a tabletop molding machine where people were looking for a way to provide a compact system. We think it might fit into the micro-molding industry.” The 150-lb Micro is available in air-cooled and water-cooled condensing styles, both with cooling capacities of 1/4 or 1/3 ton.
Conair also has an air-cooled 1/4 ton mini in its new, economical VL Series of portables. Advantage Engineering has a 1/4 ton air-cooled unit, too, and Sterling, Inc. has added a 1/2 ton unit to its SMC Portable Chiller line.
Standard portables are getting smaller
At the same time that smaller capacity portables are being introduced, the dimensions of standard workhorses are getting smaller. Citing design innovations like more compact compressors, Conair claims to make chillers having the smallest footprint in the industry; 40 per cent smaller than those of comparable capacity made by other firms. Called Series 1 and Series 2, these air- or water-cooled chillers use programmable logic controls, touch-screen displays, non-ferrous plumbing and stainless steel tanks. Most use scroll compressors, and water-cooled units have brazed-plate condensers. Conair’s new VL Series of portables includes six air-cooled models under four tons. The air-cooled models range up to 30 tons, while the water-cooled line goes up to 40 tons. These units are built on galvanized steel frames and have insulated reservoirs made of polyethylene. The air-cooled models also have 50 percent hot-gas bypass.
Sterling, Inc. recently introduced an upgraded version of the Sterlco SMC 2 and 3 air- and water-cooled chillers. They feature a smaller footprint, scroll compressors, microprocessor controller, non-ferrous piping and hot-gas bypass. The company also introduced upright units in its Royal series of temperature controllers. They are designed for processes requiring control from zero to 250* F.
Mold Temp Applications Ltd. has launched a new line of portable water and air-cooled chillers, The Beacon Chill Pac. The Beacon’s capabilities range from one to 40 tons, and systems are built to match process specific requirements, assuring proper size and efficiency for each application.
Mokon’s Iceman SC Series of chillers are equipped with a hot-gas bypass system which stops short cycling of the compressor under low load conditions, allowing the compressor to run continuously at higher efficiency levels and last longer.
Temperature Corporation’s Roger Lambert is a hot-gas bypass enthusiast. Says Lambert: “I think hot-gas bypass should be on all portables, although I realize that some people don’t see it that way.” Lambert’s company makes small footprint mini portables in the one ton to 4.5 ton range, and standard portables ranging from 4.5 tons to 25 tons. Both styles are available in air-, water- and remote condenser air-cooled models. Stainless steel base frame, pump and tank, and brazed-plate evaporator are standard on all models. Hot-gas bypass allows capacity control down to 50 percent of full load on single compressor models, and down to 25 percent of full load on dual compressor units.
Freeze Co. Systems recently introduced its FCAC series of portable process water chillers. Capacities range from one to 20 tons. Several options are available, and custom cabinets and finishes are also offered. Tuc also makes portable chillers that range up to 25 tons in either air- or water cooled configurations. Berg Chilling Systems Inc. recently expanded its range of portable chillers to include higher-capacity machines. Air-cooled models now go up to 20 and 30 tons, while water-cooled and remote air-cooled units include 20- to 40-ton models.
Molding of some engineered resins occurs at extremely high temperatures. Temperature control at these higher levels is important. The Spaltemp Series 2000 Water Circulating Temperature Control system is ideal for engineering resin molding. According to Paul Sproule at Spaltech International: “Spaltemp units can maintain accurate temperatures from as low as the ‘cold water supply’ to our systems, up to 300*F (for water) and 650*F (for oil). Our units are often supplied by a chilled water source, but the temperature control of the process is done by the Spaltemp unit.” The units will fit underneath most plastics processing equipment and can be stacked to conserve floor space.
Encirc’s new Energy Wise chiller series are equipped with an “ambient miser” to provide free cooling when the ambient temperature approaches 45*F. When the ambient miser is in operation, the refrigeration system is unloaded then completely shutdown, while 100 percent cooling is provided by ambient cooling. These chillers are available in 10 to 80 tons capacities in either a pump-packaged module or central with no pumps.
On the central chilling side, Advantage Engineering now makes a new outdoor package chiller — the OACS — in capacities from 15 to 80 tons.
Thermal Care recently introduced the TX Series of central chillers, available in capacities from 82 to 127 tons. They feature rotary screw compressors, giving them lower torque, fewer moving parts and improved performance and reliability.