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The pull down time is defined as the necessary time to cool down the ULT freezer from ambient temperatures to the selected temperature of −80 to −86 °C (−112 to −123 °F). The time strongly depends on the type of insulation, the efficiency of the compressor system as well as the installed
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tubes and microtubes, generally inside storage boxes that are commonly made of cardboard, polymer plastics or other materials. Microtubes are placed in storage boxes containing a grid of dividers that typically permit 64, 81, or 100 tubes to be stored. Standard ULT freezers can store approximately
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should be as efficient as possible. Additional inner doors reduce the loss of temperature when opening the main door. Icing within the ULT freezer should be reduced to a minimum. Modern ULT freezers employ variable speed drives for both the compressors and fans. This has reduced energy
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had more than 2,000 ULT freezers, which used an estimated 40 billion BTUs of energy and cost the university $ 5.6 million annually. Newer ULT freezers consume less energy. Nonetheless, a comprehensive report published in 2015 by the Center for Energy
Efficient Laboratories (funded by
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that stores contents at −80 to −86 °C (−112 to −123 °F). An ultra low temperature freezer is commonly referred to as a "minus 80 freezer" or a "negative 80 freezer", referring to the most common temperature standard. ULT freezers come in upright and chest freezer formats.
415:
261:
Gumapas, Leo Angelo M.; Simons, Glenn (2013). "Factors affecting the performance, energy consumption, and carbon footprint for ultra low temperature freezers: Case study at the
National Institutes of Health".
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utility companies as part of their
Emerging Technologies program) found that laboratories in California consumed an estimated 800 GWh/year, with ULT freezers being the greatest contributor to that total.
88:, cell extracts, or reagents. To reduce the risk of sample damage, these types of samples need extremely low temperatures of −80 to −86 °C (−112 to −123 °F). Mammalian cells are often stored in
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at −196 °C (−320.8 °F). Cryogenic chest freezers can achieve temperatures down to −150 °C (−238 °F) to −152 °C (−242 °F) and may include a liquid nitrogen backup.
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At least as early as 2018, some scientists suggested that laboratories set freezers to –70 °C instead of –80 °C to conserve energy and decrease wear on the freezer's compressor.
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metal shelves within the freezer. At the start of the twenty-first century, ULT freezers were able to cool down within 3 to 5 hours. Warm up time is typically 1/8 °C per minute.
416:"Ultra-low Temperature Freezers (ULT Freezers) for Food Preservation Market 2021 Overview: Manufacturing Cost Structure Analysis, Growth Opportunities & Restraints to 2026"
218:. This technology was developed in the mid-1990s, and improved efficiency by up to 30% over the conventional CFC or HFC gassed freezers. Alternatively ULT freezers may use the
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claimed that "older model" ULT devices could consume "up to 30 kWh/day". A sales pitch written in 2023 quoted "16-22 KWh of electricity per day".
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https://www.eppendorf.com/product-media/doc/en/569868/Freezers_Flyer_Cryocubes-cooling-liquids-Future-Cooling-Liquids-ULT-Freezers.pdf
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ULT freezers are commonly fitted with alarm systems that will remotely alert designated parties in the case of a freezer failure.
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ULT freezers are widely used in fish and meat preservation. The tuna fishing industry requires the use of ULT freezers.
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Depending on the volume of the freezer, the opening frequency of the users as well as the number of samples, the
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https://www.epa.gov/sites/default/files/documents/Energy_and_Global_Warming_Impacts_of_HFC_Refrigerants.pdf
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starts from ca. 11 kWh/day and higher. The US government calculates 20 kWh/day. A study performed at the
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https://public.websites.umich.edu/~nppcpub/resources/compendia/CHMEpdfs/CHME_CFC-Free_Refridgerator.pdf
195:(CR) system use up to 20 times the energy footprint of household fridges, and used to refrigerate with
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showed that the New
Brunswick U570 HEF model consumed slightly under 10 kWh/day. Without any data, the
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In contrast to short term sample storage at +4 to −20 °C (39 to −4 °F) by using standard
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447:"Environmental Profiles of Stirling-Cooled and Cascade-Cooled Ultra-Low Temperature Freezers"
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324:"Long-term Cryopreservation of Human and other Mammalian Cells at −80°C for 8 Years"
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658:"ULT Freezers: Reducing Costs and Increasing Efficiency Improving Sustainability"
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574:"Low Temperature Freezer Technology and Energy Efficiency | ENERGY STAR"
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https://eia.org/wp-content/uploads/2014/07/Putting_the_Freeze_on_HFCs.pdf
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https://www.ed.ac.uk/files/atoms/files/efficient_ult_freezer_storage.pdf
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506:"Market Assessment of Energy Efficiency Opportunities in Laboratories"
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Due to the low temperature, ULT freezers consume high amounts of
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Boxes commonly used for storage of samples in laboratory freezers
480:"Freezer Retirement Program: Out with the cold, in with the new"
264:
World Review of
Science, Technology and Sustainable Development
16:
Freezer used for storing contents at unusually low temperatures
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531:"To find hacks for greening your lab, start with the freezer"
298:"Ultra-Low Temperature Freezer Program | Penn Sustainability"
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A scientist placing samples into a negative 80 degree freezer
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A two-cycle cascade refrigeration process schematic diagram
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Biological samples in ULT freezers are often stored in
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consumption a further 30% to typically 8.5 kWh/day.
222:in reverse (A Stirling cooler) for refrigeration.
76:" infrastructures) for biological samples like
139:and hence are expensive to operate. In 2010,
377:"Evolution of Lab Refrigerators and Freezers"
23:A standard upright negative 80 degree freezer
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672:"How do Ultralow Temperature Freezers Work?"
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445:Berchowitz, David; Kwon, Yongrak (2012).
206:). Modern ULT freezers employ HC (i.e.,
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529:Drahl, Carmen (1 September 2018).
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340:10.1111/j.1537-2995.2009.02482.x
535:Chemical & Engineering News
478:Dickey, Gwyneth (2 June 2010).
1:
391:"Cryogenic and Freezer Boxes"
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191:ULT freezers that employ the
302:www.sustainability.upenn.edu
154:San Diego Gas & Electric
104:350 to 450 microtube boxes.
64:laboratories need long-term
210:) gas mixtures: typically,
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276:10.1504/WRSTSD.2013.050786
150:Southern California Edison
146:Pacific Gas & Electric
169:University of Edinburgh
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173:University of Michigan
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187:Refrigeration cycle
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56:or freezers, many
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558:11 November
489:11 November
400:27 February
361:27 February
328:Transfusion
307:11 November
208:hydrocarbon
92:containing
40:Application
831:Categories
514:24 October
248:References
180:insulation
72:" and/or "
70:cold chain
801:cite news
765:cite news
729:cite news
694:cite news
631:cite news
596:cite news
284:110910956
356:20075515
348:19912586
236:See also
86:proteins
791:. 2014
755:. 1997
270:: 129.
242:Dry ice
216:propane
101:polymer
354:
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282:
212:ethane
204:R-508B
152:, and
90:dewars
509:(PDF)
352:S2CID
280:S2CID
31:is a
814:help
778:help
742:help
707:help
644:help
609:help
560:2020
516:2022
491:2020
427:2021
402:2021
363:2021
344:PMID
309:2020
214:and
459:doi
336:doi
272:doi
82:RNA
78:DNA
60:or
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Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
