Whirlpool Corp. is using a vacuum panel to replace some of the polyurethane foam insulation in a new generation of superefficient refrigerators. The appliance major is the first in North America to announce its use of vacuum panels in a commercial program. Vacuum panels are an option for meeting stringent energy efficiency targets and for reducing the use of ozone-depleting chemicals in refrigerators. The panels are excellent insulators and do not need ozone-depleting blowing agents. What's more, they are thin so refrigerators do not need bulky outside dimensions unwanted by consumers.
Because vacuum panels are more costly than conventional polyurethane foam insulation, appliance majors have been slow in using them. However, urethane suppliers have developed their own vacuum panel versions - just in case.
Whirlpool uses two Aura Superinsulation panels in the freezer-side wall in the second generation of its Energy Wise side-by-side refrigerators, which have 22-27 cubic feet of capacity. The company claims the Aura panel helps these refrigerators consume 38-41 percent less energy than 1993 Department of Energy standards.
Aura, supplied by Owens-Corning Fiberglas Corp. of Toledo, Ohio, is a vacuum panel containing fiberglass encapsulated in a stainless-steel foil skin. Owens-Corning claims Aura's insulation value is as high as R90 per inch, well above the R10 typical for foamed urethane, and two to three times better than competing vacuum panels.
The insulation efficiency, however, comes with a price.
``It's one of the most expensive things we've done for the energy efficiency rating,'' said Duane Schmidt, Whirlpool's launch team manager for side-by-side refrigerators.
The refrigerator's energy efficiency also relies on engineering techniques such as improved compressors and fan motors.
Schmidt said Whirlpool uses two panels in the freezer-side wall. Each panel measures about 2 feet by 3 feet and is an inch thick. Workers glue the panels to the cabinet wall before the freezer liner is installed. Workers then spray urethane foam into the wall construction.
Schmidt would not disclose the extra material and assembly costs of the vacuum panels, which he called ``substantial.'' Bob King, Bayer Corp. vice president of technical insulation, estimates direct costs of such panels as four times higher than urethane foam on a square-foot basis. Panel prices could come down with mass production.
Polyurethane insulating foams so far have held their own against vacuum panels in refrigerator production.
``The cost factor is still key,'' said Doug Kunnemann, Dow Plastics' senior manager of large and portable appliances.
Dow and Pittsburgh-based Bayer, the major North American suppliers of urethane foams for appliances, are ready with their own vacuum panels if their foams lose market share.
Dow is working on a vacuum panel containing an undisclosed thermoplastic filler, Kunnemann said in a telephone interview from Dow's Midland, Mich., headquarters. Last year the firm introduced a vacuum panel based on microcellular polyurea xerogels but Kunnemann said its recent emphasis is on thermoplastic filler in the panels.
``We believe there is probably a market for vacuum panels in niche applications,'' he said.
Bayer's German parent, Bayer AG, has developed a vacuum panel containing post-consumer recycled polyurethane foam, King said.
Polyurethane producers also are trying to produce better insulating foams ``or else the industry will lose volume to vacuum panels,'' King said.
But getting a more insulative foam while cutting back ozone-depleting blowing agents is tricky. Urethane suppliers are working with various hydrochlorofluorocarbons and hydrocarbons, carbon dioxide and other blowing agents. Depending on the option, there are compromises in insulation ability, ozone-depletion potential or suitability to current manufacturing lines.
Whirlpool so far is not overly concerned with costs in its Energy Wise line. The new refrigerators in effect are subsidized by the 24 utilities in the Super Efficient Refrigerator Program, which put up $30 million in 1993 for development of more efficient refrigerators that do not contain CFCs. Whirlpool won first prize in the SERP competition last year.
``We sell the new fridges at the same price as [standard models] because SERP covers the costs for additional [energy] features,'' Schmidt said.
The refrigerators are sold in SERP utility markets across the United States.
Whirlpool is committed to making 250,000 refrigerators in the SERP program, which is expected to last a few more years. Its first 35,000 refrigerators - the first-generation Energy Wise model - used only urethane foam insulation. Whirlpool plans to make the second generation with freezer-side vacuum panels for the rest of the SERP production run. It produces SERP refrigerators at its Fort Smith, Ark., plant.
Schmidt said his firm also developed its own vacuum panel - a silica-filled version in a polyester film pouch - which it is using in some SERP refrigerators. He admitted that its insulation properties are lower than Aura's. Whirlpool first used its own vacuum panels as a regular feature in a KitchenAid refrigerator a few years ago.
Kunnemann said most appliance majors have evaluated vacuum panel insulation, but probably will continue with urethane insulation for 1998 DOE energy efficiency targets.
GE Appliances officials neither confirmed nor denied rumors that their firm has begun using vacuum panel insulation.