Woburn, MA —The MuCell® process from Trexel uses supercritical fluids of atmospheric gases (CO 2 and N 2 ) to create evenly distributed and uniformly sized (5-50 micron) cells throughout thermoplastic polymers (see DN, 09.20.99 p. 105). While most users stress the numerous material benefits the process affords, very little attention has been paid to energy savings.
An engineering study recently commissioned by Western Massachusetts Electric Company (WMEC) found that with a marginal electric rate of about 4¢/kWh, and a marginal demand rate of $13.89/kW, the MuCell process would save over $16,000 annually on a new 400-ton molder. In a pennies business, that's a lot of pennies.
"We're always looking for ways to reduce our customers' energy use," explained Ron Johnston, an energy conservation representative for WMEC. "A number of my customers are injection molders and I heard a lot about the MuCell technology, so I brought it to the attention of our parent company, Northeast Utilities, and they decided to have a consultant evaluate it."
The study, performed by W.H. Fuller & Company (Glastonbury, CT), was based on various tests performed at Trexel. These tests showed savings from the following sources:
A reduction in clamp tonnage leading to a reduction in motor horsepower.
An increase in productivity due to reduced processing time.
A reduction in electric resistance heater usage since there is less material to be heated with MuCell, and consequently,
A reduction in chilled water costs.
Based on their analysis, W.H. Fuller concluded that the process would generate substantial savings compared to a conventional machine, especially when increased production is taken into account. Using the 400-ton unit as an example, Fuller calculated reduced kWh usage of 298,698 per year, and reduced demand of 24.62 kW. In Western Massachusetts Electric's territory, that calculated to $16,407 per year in savings.