News > Industry News All about natural hydrocarbon refrigerants in cooling & refrigeration: News, Products, Jobs, Events, Knowledge, Forum, B2B Networking.Concerns with carbon footprint are spurring innovations in ultra low-temperature (ULT) refrigeration, required by most laboratories to store samples, reagents, antibodies and enzymes. Several companies now offer zero ODP and low GWP hydrocarbon freezers. Below we look at some of the ULT hydrocarbon products on offer. ![]() ULT hydrocarbon laboratory freezers keep cell samples and reagents cool Ultra low-temperature (ULT) laboratory freezers can achieve temperatures of -40°C to -86°C, in contrast to domestic freezers, which operate to about -20°C. As well as reliably reaching and maintaining low temperatures, ULT freezers must be energy efficient. Hydrocarbon technology provides an excellent, environmentally friendly solution for this type of application.
Hydrocarbon ULT freezers available
Buyers can opt for a range of numerous hydrocarbon options when selecting a low-temperature laboratory freezer, some of which include:
Development of hydrocarbon low-temperature freezing
In 2007 New Brunswick Scientific (NBS) was among the first to offer an eco-friendly and cost-saving “Green Freezer” line in which high GWP HFC refrigerants were replaced with hydrocarbons refrigerants. The new design significantly lowered energy consumption and operating costs. At the time these freezers were not available in the U.S., where use of hydrocarbon refrigerators was not yet permitted.
However, following the recent US EPA approval of three hydrocarbon refrigerants, it seems likely the market for ULT freezer technology is set to see greater interest in hydrocarbon technology.
How ULT freezers operate
Laboratory freezers generally apply vapour compression with a single compressor to reach the -40° to -50° C range. A second compressor is required to cool below that point. To achieve energy efficiency and extend the life of the compressors, the low-stage compressor turns off automatically when the set-point temperature is reached, while the high-stage compressor remains on continuously.
It is vital that ULT freezers maintain uniform temperature throughout the unit and recover quickly from openings. Opening the freezer door introduces warm, moist air that causes the device to work harder to retain its set-point temperature and causes condensation and freezing of water vapour inside the unit. The speed at which a freezer recovers from temperature excursions is a function of BTU reserve capacity.
New trends in ULT cooling mechanisms include liquid nitrogen technology that does not use a compressor. |