Karl von Kries has a vision of harnessing the sun to make plastic products.
The CEO of LightManufacturing LLC said he and co-workers have developed a way of rotational molding plastic parts without relying on an electricity grid. Sun energy is focused by mirrors to heat a rotational mold and photovoltaic cells generate electricity to run the rotomolder's armature.
“It's good where energy costs are high,” von Kries said in a telephone interview. Areas where the technology is most practical include the southern U.S., Africa and Australia. “Nearly half the earth's surface is viable for solar rotomolding,” he said.
LightManufacturing's technology relies on tensioned, metalized PET membranes, or heliostats, to track the sun's position and act like mirrors. Small solar rotomolding plants can be placed near customers to avoid high transportation costs for bulky items like agricultural tanks, he said.
“We will supply turnkey systems of the heliostats, armature and photovoltaic array to small companies,” von Kries said. Large companies with engineering departments could work with LightManufacturing to develop production systems.
LightManufacturing runs a test facility at its Pismo Beach, Calif., head office. It tests about 25 22-square-foot heliostats, each capable of making tanks that hold several gallons of water. As a rule of thumb, an 11-square-foot heliostat can generate about 1,000 watts of energy in full sunlight.
Von Kries got the idea for solar rotomolding several years ago when he worked as a mechanical engineer on new product design with a New England rotomolder.
“I was out in the plant with these [rotomolding] machines and it struck me as an inherently wasteful process. I thought, ‘Why couldn't we do this with solar heat?' “
Energy to run rotomolding ovens accounts for about 30 percent of the cost of the rotomolded product, von Kries said. Typically, ovens run on natural gas and in total emit more than 2 billion pounds of greenhouse gas emissions annually while molding more than 3.6 billion pounds of plastic.
“We use solar energy in its raw state and capture it,” von Kries said. The technology circumvents traditional solar strategies of converting the sun's rays to electricity, which then must be transmitted some distance for use. And unlike conventional sun-to-electricity programs, LightManufacturing's approach does not rely on subsidies.
Von Kries said he is working on expanding solar heating to other processes, including injection molding and blow molding. Implementing the technology would probably be more capital-intensive for those processes than for rotomolding and probably would entail the use of light pipes to bring solar energy into a plant.