Liquid Nitrogen Freezer Life Cycle Assessment

[Rashmi Sahai]

Hi Green Labs Colleagues,

 

A few months ago I had reached out to you to learn more about the energy consumption of liquid nitrogen (LN) freezers versus compressor-based (CB) freezers for -140 sample storage. Although the electricity consumption of an LN freezer is negligible compared to a CB freezer, I wasn’t comfortable promoting LN freezers as an energy-efficient alternative until I learned more about the offsite energy and greenhouse gas impacts of producing liquid nitrogen.

 

Last quarter, a group of Stanford students completed the attached life-cycle assessment comparing the two technologies and found that even when incorporating the production of liquid nitrogen, the life-cycle energy end greenhouse gas impacts are an order of magnitude lower for the LN freezers than the CB freezers. The study also evaluates several other environmental metrics. I think these are exciting results for LN freezers and hope that the study can help inform your programs.

 

Best,

Rashmi  

 

Rashmi Sahai, M.S., C.E.M.

Assessments Program Manager, Office of Sustainability

Department of Sustainability and Energy Management

Stanford University

650-736-7636 | rsa...@stanford.edu | sustainable.stanford.edu

 

[Lee, Gail]

Thanks Rashmi!  This is very interesting. 

 

I just wanted to offer a few other options to consider:

 

There is a new LN2 freezer called the Fusion,  that uses recirculating nitrogen, however the energy use is comparable to a ULT.  It just does not need LN2 deliveries but once. 

 

The Stirling freezer is not compressor based, but uses the Stirling engine which uses half the energy of a conventional ULT and generates less heat.

 

The footprint of a LN2 dewar is the similar to a ULT but provides only half the capacity. 

 

UCSF is now looking at off-site storage, room temperature storage, and inventory management technologies.

 

Gail Lee

UCSF Sustainability

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[Allen P Doyle]

Hi Rashmi,

               This is a fascinating issue, and could use more investigation. I look forward to reading the report. 

LN2 may have a high GHG content or negligible depending on the perspective, and could use more digging. Neill Lane at Global Cooling mentioned he has calculated a high CO2e, while a colleague at one of the suppliers suggested that LN2 has negligible embodied GHG because it is a “by product” of O2 production, and just looking for a good use.  Alissa Kendal at UC Davis might be a good reviewer of this report, as her research group does LCA’s on a wide range of products.

The floor space and first cost also figure in. The largest Dewars are $30-40k, and can hold ~2 freezers worth of storage.  A sleeper issue is sample management—do people get rid of expired samples the same or different in LN2 Dewars. 

There is also a difference on maintenance and costs depending on whether LN2 is manually delivered or through centralized pipes.

Another aspect that higher education is lousy at is “monetizing risk”—ie that LN2 is safer in power outages.

               To be continued!

                              Allen

Green Laboratories and Green Procurement Project Manager, Retired

 

I will remain in energy and resource conservation.

You may reach me at apdoy...@gmail.com

805 729 1581

University of California, Davis

530 752 2075

1 Shields Avenue,  436 Mrak Hall         Davis, CA  95616

[Susan Vargas]

Rashmi,

 

Did the students consider comparing LNF to Stirling-cycle-based freezers as well?

 

Susan

 

********************************

Susan Vargas

Senior Energy Management Specialist

Stanford University

650-723-4570

susan....@stanford.edu

 

 

 

 

 

From: green-lab...@googlegroups.com [mailto:green-lab...@googlegroups.com] On Behalf Of Rashmi Sahai
Sent: Tuesday, January 30, 2018 4:42 PM
To: green-lab...@googlegroups.com
Subject: Liquid Nitrogen Freezer Life Cycle Assessment

 

Hi Green Labs Colleagues,

--

[Barry Reid]

Just in case it is important... are you aware that there are LIQUID nitrogen generators available now? (In the U.K. a company called Nobelgen makes them)... they can make up to 70litres a week - useful if you have a remote location that is difficult/expensive to get a LN2 truck to it...

Regards,

Barry.

 

    

Barry J Reid BSc
Life Sciences Manager
GPE Scientific Limited, Greaves Way Industrial Estate, Stanbridge Road,
Leighton Buzzard, Bedfordshire, LU7 4UB, United Kingdom
T: +44 (0) 1525 382277
F: +44 (0) 1525 382263 M: +44 (0) 7387 106883
barry...@gpescientific.co.uk
www.gpescientific.co.uk