CSU teams up to reinvent the freezer


As energy prices have some supermarkets feeling the heat, CSU researchers work to make refrigeration a cooler and more cost-efficient option for companies. The IcePoint Project, a collaboration with Rebound Technology, is a six month research process to develop a functioning system to reduce 45 percent of energy used by conventional freezers.



“Normally what’s happening with supermarkets is those freezers run all day long and during the middle of the day on the hottest days of the year. It is running when everybody’s demand for electricity is high for air conditioning and the like. That puts a strain on the electric grid,” said Dan Zimmerle, head of research for the project.


The refrigeration system will include three steps. The first step is creating ice through the night when the demand for energy is low.


“You get two benefits from making ice at night. One of them is that the electricity costs less. Second, it is cooler outside so the refrigeration is more efficient,” Zimmerle said.


The second part of the process is to take the ice and melt it by mixing it with a special salt to create a very cold fluid, according to Kevin Davis, chief executive officer of Rebound. This salt and water mixture, called brine, freezes at a lower temperature than just water. This brine is used as a refrigerant meant to maintain the temperatures of the freezers.


“We are creating ice at night and melting it slowly while mixing it with a salt which makes a -35 °C fluid. We use that cold temperature fluid to maintain the freezer temperatures,” Davis said.



The third step of the process has to do with preparing the water to freeze again. They use a hydrophobic material that passes water vapor through microscopic pores while preventing the salt from passing through.


“What I am describing is a close loop system. Now after that separation, you are left with the pure water to freeze again at night and the salt ready to mix with the ice,” Davis said.


CSU is working on construction, commissioning and testing of the prototype which will allow graduate and undergraduate students to aide in the project.


“We are assisting in two ways for the project. The first is we are providing some simulation. We are going to provide some techno-economic modeling. The second part is we are providing laboratory facilities and experimental support,” Zimmerle said.


A successful project will result in a healthier environment, according to Davis. Conventional refrigerants, called hydrofluorocarbons, are damaging to the atmosphere and are 3,000 times more dangerous for the environment than carbon dioxide.


“A big bonus to our system is that this brine is a natural refrigerant which means that it doesn’t have a very high global warming potential,” Davis said.


The target consumer for the finished project is large supermarkets.


“This is going to show up primarily in commercial operations. The improvement on efficiency might be fairly significant,” Zimmerle said.


ASCSU Beat Reporter Stephanie Mason can be reached at news@collegian.com