Colorado State Researchers Collaborating on Commercial Freezer Technology

Colorado State University researchers are teaming with a Boulder company to develop a commercial refrigeration system that could save supermarkets up to 65 percent on their low temperature cooling – or freezer – costs.

Rebound Technology was awarded a six-month $141,507 National Science Foundation small business grant to build a prototype of its IcePoint system, which relies on stored energy to keep supermarket freezers at their target temperature. Researchers at CSU’s Energy Institute will help build and test a working 2-kilowatt prototype.

“We are providing technical support, including prototyping, testing and simulation said Dan Zimmerle, the CSU research scientist responsible for the project.

This is the second CSU/Rebound project announced in the last month.

Rebound recently received a $1.37 million federal grant to develop a solar-powered refrigeration system for use in developing countries where there is little access to reliable electricity. CSU Energy Institute researchers are building a prototype and will help test the SunChill system at farms in Mozambique.

“It’s been a very beneficial relationship for us,” said Kevin Davis, Rebound’s chief executive officer. “(CSU) has the resources and technical expertise to help us advance our technologies.”

Zimmerle, who also is working on the SunChill project, agreed.

“(The Energy Institute) tries to act as an incubator and work with companies like Rebound early on to help them develop their products,” he said. “Our relationship with Rebound is a good example of how we can assist startups.”

The IcePoint technology creates ice at night – during what utilities typically call “off-peak” hours – when demand for electricity is low and less expensive.. As the ice melts, it mixes with a salt to create a – 35° C brine that keeps food frozen throughout the day.

The design eventually separates the brine into pure water and salt and then reuses both as part of a closed-loop cycle.

“The concept is similar to an old-fashioned ice cream maker, but operating in a closed-loop cycle,” Zimmerle said.

Part of the savings is because of the technology’s design — IceChill uses electricity only at night, unlike conventional, compressor-based refrigerators that draw power all the time. The rest is from capitalizing on lower “off-peak” power rates.

Davis said initial tests indicate the IcePoint design uses 45 percent less energy than conventional systems by mitigating the use of compressors.

“Supermarket compressors are energy hogs that operate 24/7,” Davis said. “IcePoint doesn’t need a constant supply of compressor power to provide cooling. Cost savings plus the environmental benefits of a natural refrigerant make IcePoint’s potential very attractive.”

The team hopes to make enough progress on the technology to secure an additional National Science Foundation grant to validate a commercial-scale system.