The company name on the press release—Entropy Thermal Management Technologies—caught our eye (and, we must admit, sent us running to the dictionary). Entropy, according to The American Heritage Dictionary, is "a quantitative measure of the amount of thermal energy not available to do work in a closed thermodynamic system."

What does thermal energy have to do with shipping? For one thing, thermal energy—think heat—can create all sorts of headaches for cold-chain shippers. To address that problem, Entropy has developed Greenbox, a temperature-controlled shipping container for industries like pharmaceuticals and biotechnology.

What's unusual about Greenbox is the patented "phase-change material" (PCM) that controls the temperature inside the container. The PCM inside the unit's walls absorbs large amounts of heat. When the PCM's temperature reaches the point at which it changes phase—that is, it begins to change from solid to liquid—it continues to absorb heat but with no appreciable rise in temperature. When the ambient temperature around the liquid falls—when the box is loaded onto an unheated truck in winter, for instance—the PCM solidifies, releasing the stored heat.

That's highly simplified, but the upshot is that the technology allows Greenbox to maintain a narrow range of temperatures for a remarkable 120 hours, or five days. That means users can ship chilled, room-temperature, and frozen products any day of the week, by any transport mode, without worrying about weekend holdups.

The reusable, fully recyclable plastic cartons are available in several sizes, including the new 16-cubic-foot Pallet Shipper Greenbox. Entropy says the pallet- mounted box can be reused up to 250 times, can be assembled by one person in minutes, is stackable two-high, and is collapsible for storage. What's more, Entropy uses a unique biodegradable vegetable-based PCM instead of the usual petroleum-based materials.

More information, including an explanation of the science behind the temp control system, can be found at www.greenboxsystems.com and www.entropysolutionsinc.com.