issue: May 2007 APPLIANCE European Edition
Refrigeration Systems & Compressor Technology
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by Lisa Bonnema, Senior Editor
Whether improving system efficiency or making the environment healthier, the refrigeration industry is dedicated to designing high-tech products that achieve more than their basic function.
The ICF valve station is one the latest integrated solutions from Danfoss. The unit can reportedly replace manual valves, solenoid valves, regulation valves, motorized valves, and other components with a compact block, incorporating a number of different functions in the same component.
Efficiency. A simple word with a simple meaning, yet it has managed to create a whirlwind of activity in every design room of every product manufacturer around the world. And the refrigeration industry is no exception.
The challenge, of course, is designing refrigeration systems that save energy, save costs and, as far as some are concerned, save the world. The good news is that both OEMs and their suppliers seem up to the task, creating innovative technologies that often meet all three demands.
Danfoss feels that the demands of today’s refrigeration companies are very clear. “We see an increasing demand for products which are improving the energy efficiency of our customers’ appliances. ‘Being green’ becomes one of the most effective ways to promote an organization,” confirms Markus Draeger, strategic marketing director for Refrigeration and Air Conditioning at Danfoss in Flensburg, Germany. “On a global scale, the initial costs of new solutions are still one of the most important—in many cases, the most important—buying factor.”
In addition to researching new natural refrigerants like CO2, Draeger says that one of the major focuses of Danfoss is offering more integrated solutions like the company’s Plug & Cool cassettes for the vending machine and bottle cooler segments. The cassettes are designed to function as self-contained refrigeration systems, complete with compressor, heat exchangers, fans, controls, piping, and all other necessary components. OEMs simply insert the units at the bottom of the cabinets, and the cooling process will be quickly up and running.
Another example is the company’s ICF valve station, which can be used to replace manual valves, solenoid valves, regulation valves, motorized valves, and other components with a single block, incorporating a number of different functions in the same component. It is compact and said to be easy to assemble, with a reduced number of soldering points between components. Its one-piece body reportedly provides ports for up to six function device modules that are configured specifically for a customer’s application and shipped as a complete subassembly, ready for installation into the OEM’s products.
Compressor manufacturer ACC Spain says it has two major innovation targets—energy efficiency and use of natural refrigerants. “These two lines are not independent but fully correlated,” says Miquel Jornet, ACC Spain technical relationship director. “Energy efficiency is a key point, and not only because of environmental reasons, but economical and political too.”
In terms of compressor design, Jorent says energy efficiency means an improvement of volumetric efficiencies acting on its mechanical design and higher electrical motor efficiency. “According to market needs and cost constraints, the game is providing a product that is able to work on different levels of efficiency by just changing electrical accessories, giving high flexibility of the stock, adopting cheaper solutions, and having reliable and small physical dimensions,” he explains.
In regards to natural refrigerants, ACC is researching the use of hydrocarbons such as R600a (isobutane) in the household. According to Jornet, this is already a winning refrigerant in Europe and is being successfully used in other areas like China and Japan. He also says R290 (propane) is progressively gaining market share in commercial refrigeration
One of the company’s more novel projects is its “New S” series, which is an updated version of the current S series with improvements in noise emission and performance. The new design eliminates the compressor’s flat surface for a more compact and rounded surface that is said to reduce the noise level as well as the vibrations. The company notes that new S shell does not affect the compressor’s dimensions and should properly fit in equipment without major changes.
The new series includes models for commercial refrigeration applications in the range of displacements from 26 to 34 cc, for both LBP and HMBP, working with R134a and R404A refrigerants.
Some refrigeration technology companies like Carel S.p.A are going above and beyond offering their customers energy-saving solutions; they are putting the research behind their products to prove their performance claims. As part of a series of field tests, seven Italian supermarkets are currently operating with both traditional refrigeration technology and Carel electronic technology to gather data for comparative analysis of the two solutions.
According to the company, the use of its E2V series of electronic expansion valves and the matching control systems has made it possible to reach maximum efficiency in the control of refrigeration utilities in supermarkets. The technology has reportedly allowed for more effective temperature control and a significant decrease in the power consumption of the compressor racks.
The valves are said to optimize the operating pressure of the compressors, reducing the electricity consumption by up to 50 percent, without affecting system performance. In fact, the company says that by exploiting the features of both the valves (both at very low and very high loads) and the electronic control system, the condensing pressure in the installation can be kept lower whenever the room temperature is below 30°C.
With traditional refrigeration technology, Carel says mechanical thermostatic valves force the compressors to always operate near maximum pressure (corresponding to the summer period), as they can’t adapt to different conditions without affecting equipment performance. The pilot tests, however, are using a more complex system that allows the supermarkets to operate with traditional or electronic technology on alternating days, measuring the consumption of the entire refrigeration system, including the compressors, fans, defrost heaters, etc. So far, test results have shown that the electronic technology is offering energy savings ranging from 18 percent to 48 percent.
In addition to saving energy and money, the solution is also said to reduce atmospheric carbon dioxide emissions due to the decrease in electricity consumption. Carel hopes that this will offer companies future savings based on national and European subsidies that implement reductions in atmospheric carbon dioxide emissions.
The Bottom Line
While technology can certainly take the industry to the next level, everyday issues such as production efficiency and cost continue to be at the top of every OEM’s priority list. “As a manufacturer, our biggest current concern is to receive timely shipments so we can meet our production schedules,” says Jack Sinkler, vice president of marketing for Rheem’s Heating and Cooling Division. “Due to the large demand swings that are typical in our industry, we need a supplier to be reliable, even when our demand decreases and increases with weather patterns, legislation, etc.”
Fort Smith, Arkansas, U.S.-based Rheem has explored consignment programs and other methods of vendor managed inventory (VMI) to more efficiently integrate the company’s MRP requirements directly into those of its key suppliers. “This is the type of collaboration that we need to efficiently manage the flow of materials into our manufacturing processes,” Sinkler tells APPLIANCE. “Moving forward, we’ll be seeking additional progress with these types of programs and support tools to continually better manage the flow of our key components.”
Of course, cost is also of utmost concern, especially when it comes to critical system components. “It is important for us to partner with suppliers that can provide us a reliable and competitive product in terms of costs and consistent performance,” Sinkler says. “The cost of the compressor represents such a large percentage of total material costs that it is crucial to ensure our long-term ability to remain competitive.”
Sinkler says one of Rheem’s current initiatives is integrating key suppliers into the company’s product development programs as well as directly linking them with production schedules to help assure components arrive at plants when needed. “As key suppliers,” he says, “they must have the ability to respond with new products that meet changing customer and market needs in a timely manner to support business growth.”
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