Cold Storage
From refrigerators to ultra-low temperature (ULT) freezers, cold storage is universally crucial in storage of samples and reagents for scientists in all fields. However, these pieces of equipment take a big toll on the environment and are responsible for the consumption of up to 26 kWh/day, which is equal to the average daily energy consumption of a household in the U.S.
So, what can we do about it? Several universities and organizations have implemented educational programs and challenges to help promote simple changes in our practices that can make a huge difference, such as The Freezer Challenge. The Freezer Challenge is a program coordinated by the non-profit organizations My Green Lab® and the International Institute for Sustainable Laboratories and sponsored by various companies with an interest in promoting the most energy efficient cold storage options that also support sample integrity and accessibility.
Best practices that can make cold storage more sustainable can be divided into four categories: “good management” practices, temperature tuning, retirements and upgrades, and cutting-edge practices.1
“Good management” practices:
- full defrost of freezers when needed
- brushing out frost and removing dust from intake or coils regularly to decrease need for full defrost and support freezer function/longevity
- performing sample inventory to make it easier to find samples and shorten freezer door opening times (saves energy and protects sample integrity)
- cleaning out unneeded samples and using high density storage to maximize existing space
Temperature tuning:
- Adjusting ULT set points: “chilling up” an ULT freezer from -80°C to -70°C can decrease energy consumption by 30% on average with minimal effort if your samples can be safely stored at this temperature. Resources about what and why you should “chill up” to -70°C are available on the My Green Lab®2 and Freezer Challenge3 websites.
- Storage at appropriate temperatures: a standard -20°C freezer is less expensive and can consume 80% less energy than an ULT freezer and can be used for samples that do not require storage at ultra-low temperatures.
Retirements and upgrades:
- Retirement: retire or unplug unneeded cold storage units to save energy and space. Be sure to dispose of units responsibly. Consider donating a functioning freezer to another lab or contacting CSU Surplus Property (http://cr.colostate.edu/surplus-property.html).
- Upgrades: when purchasing new cold storage units, consider adding energy efficient or Energy Star certified products
Cutting-edge practices:
- Share cold storage units
- Barcode inventories
- Try room temperature sample storage (RTSS) for reagents
- Adopt RTSS
Authors: Sarah Cooper and Nurudeen Oketade
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