Computer simulation has solved a plastics plant problem that threatened to damage expensive equipment and materials.

The plant includes 52 molding machines that are supposed to be maintained at temperatures no higher than 78oF (26oC) to avoid damage to the control systems. Similarly, the machines' computer controls must be maintained at relatively cool temperatures to protect the semiconductors.

Temperatures had been far too high for the machines and materials. The plastics company, knowing it needed cooling equipment, discussed solutions with Applied Air, Dallas. The firm recommended installing two of its Model IFA 60,000-cfm air-turnover systems at either end of the building, blowing air down the length of the machine rows toward the middle.

The plastics firm used Flovent software from Flomerics Inc., Marlborough, Mass., to simulate the proposed solution and evaluate effectiveness. Using a personal computer, engineers viewed the simulation results, which showed that the hot machines were generating strong convective flow straight up to the ceiling. With the proposed solution, machines in the middle of the building received little or no cooling.

Because the updraft prevented horizontal flow down the length of the rows, Applied Air changed the design to have the air pass across the width of the rows. This required switching to indoor units. Re-running the simulation in optimization mode showed that 60,000-cfm units positioned to blow across the rows provided effective cooling. For more information, visit