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Stirling Ultracold ULT25NEU Portable Ultra-Low Temperature Freezer
Not every valuable biological sample remains inside the laboratory. Clinical trial specimens, biologic therapies, vaccines, forensic evidence, and research materials often need to be transported safely between laboratories, hospitals, manufacturing facilities, and field locations without compromising temperature integrity. The Stirling Ultracold ULT25NEU Portable Ultra-Low Temperature Freezer was engineered specifically for these applications, providing dependable -20°C to -86°C storage in a compact, lightweight platform that can travel wherever critical samples need to go.
With 25 liters (0.9 cubic feet) of storage capacity, space for up to 18 standard 2-inch cryoboxes, and the ability to operate from standard AC power or 12V DC vehicle power, the ULT25NEU offers laboratories, clinical teams, and biopharmaceutical organizations a portable ultra-low temperature solution without sacrificing performance. Its patented free-piston Stirling engine delivers the same dependable ultra-low temperature technology found in larger Stirling freezers while consuming less than 2.8 kWh/day at -80°C.
Organizations building a complete cold storage program often use portable ultra-low freezers alongside laboratory refrigerators for refrigerated products, laboratory freezers for intermediate-temperature storage, and full-size ultralow freezers for centralized long-term preservation. The ULT25NEU fills an entirely different role—bringing dependable ultra-low temperature storage directly to the point of collection, transport, or patient care.
Stirling Ultracold ULT25NEU Key Features
25 L (0.9 cu. ft.) storage capacity
Stores up to 18 standard 2-inch cryoboxes
Adjustable operating temperature from -20°C to -86°C
Refurbished and performance tested by American Instrument Exchange
90-day warranty included
Stirling Ultracold ULT25NEU Overview
Unlike conventional laboratory freezers designed to remain in one location, the ULT25NEU was built for mobility. Its compact footprint, lightweight construction, and flexible power options allow laboratories and healthcare organizations to transport temperature-sensitive materials while maintaining ultra-low temperatures throughout the journey.
Whether installed in a laboratory, deployed in a mobile clinical unit, or powered from a vehicle during transport, the ULT25NEU provides reliable storage for valuable biological materials. The patented Stirling engine continuously modulates cooling output without relying on traditional compressor cycling, helping deliver excellent temperature stability while minimizing energy consumption.
Portable ultra-low storage is often just one step in the sample lifecycle. Materials may be prepared inside biosafety cabinets, cultured in CO₂ incubators, processed using refrigerated centrifuges, and ultimately transferred into an ultralow freezer for long-term preservation. The TSU300A provides the dependable final stage of that workflow, protecting valuable research materials long after the experiment has been completed.
Common Applications
The Stirling Ultracold ULT25NEU is commonly used for:
Clinical trial sample transport
Cell and gene therapy logistics
CAR-T therapy transport
Vaccine distribution
Biologic drug transport
Remote research stations
Field sample collection
Hospital satellite laboratories
Public health response
Military and disaster response
Pharmaceutical manufacturing support
Its portability makes it particularly valuable whenever biological materials must remain at ultra-low temperatures outside of a traditional laboratory environment.
Ideal Laboratory & Clinical Applications
The ULT25NEU is an excellent choice for:
Cell and gene therapy programs
Biotechnology companies
Pharmaceutical manufacturers
Hospitals and healthcare systems
Clinical research organizations
Vaccine distribution programs
Academic research institutions
Public health agencies
Field research teams
Mobile laboratory operations
Temperature Recovery & Sample Protection
Transporting biological materials introduces unique challenges that stationary laboratory freezers never encounter. The ULT25NEU combines the stability of Stirling engine technology with a well-insulated cabinet to maintain dependable temperatures during transportation and deployment.
Because the Stirling engine continuously modulates cooling rather than cycling compressors on and off, the freezer maintains excellent temperature stability while consuming very little electrical power. Optional rechargeable phase-change backup modules can provide up to eight hours of passive protection at -70°C during temporary power interruptions, adding another layer of security for valuable biological materials.
Typical Stored Materials
The ULT25NEU is commonly used to transport or temporarily store:
Cell therapy products
CAR-T therapies
Stem cells
DNA and RNA samples
Clinical trial specimens
Vaccines
Blood derivatives
Plasma and serum
Tissue specimens
Pharmaceutical compounds
Biological reference materials
Temperature-sensitive research samples
Stirling Ultracold ULT25NEU Key Specifications
Capacity
25 L (0.9 cu. ft.)
Up to 18 standard 2-inch cryoboxes
Temperature Range
Adjustable from -20°C to -86°C
Refrigeration System
Patented free-piston Stirling engine
Compressor-free design
Natural refrigerants
Monitoring & Controls
LCD control panel
Audible and visual alarms
Optional wireless temperature monitoring
Power Requirements
100-240V AC
12V DC vehicle power compatible
Compatible with external battery systems
Dimensions
Exterior: approximately 27.3" W × 13.8" D × 18.1" H
Weight
Approximately 46 lbs. (21 kg)
Energy Efficiency & Operating Costs
The ULT25NEU is one of the most energy-efficient portable ultra-low freezers available, consuming less than 2.8 kWh/day at -80°C. Its free-piston Stirling engine eliminates conventional compressor systems while utilizing 100% natural refrigerants. Low power consumption makes the freezer practical for vehicle operation, remote field deployment, battery backup, and other applications where electrical power may be limited.
Specifications compiled from Stirling Ultracold manufacturer literature and American Instrument Exchange product information.
Refurbishment & Testing Process
Every Stirling Ultracold ULT25NEU received by American Instrument Exchange undergoes a comprehensive inspection and performance evaluation before shipment. Our technicians verify pull-down performance, confirm stable operation throughout the operating temperature range, inspect the Stirling engine cooling system, test alarms and electronic controls, verify AC and DC power operation, evaluate cabinet integrity, and thoroughly clean the freezer before delivery.
Shipping & Installation Considerations
Unlike conventional upright ultralow freezers, the ULT25NEU is designed for portability. Its compact size allows it to be transported by vehicle, installed in mobile laboratories, or deployed at remote collection sites. Before use, operators should verify available power sources, ventilation, and secure mounting if the freezer will be operated during transport.
Frequently Asked Questions
Can the ULT25NEU operate from a vehicle?
Yes. One of the defining features of the ULT25NEU is its ability to operate from 12V DC vehicle power as well as standard 100-240V AC electrical service, making it ideal for mobile laboratories, field research, and specimen transport.
What makes the ULT25NEU different from a standard portable freezer?
Unlike conventional portable freezers that typically operate around -20°C, the ULT25NEU can maintain temperatures as low as -86°C using Stirling engine technology, making it suitable for transporting highly temperature-sensitive biologics, vaccines, and clinical research samples.
Can this freezer be used for cell and gene therapy logistics?
Yes. The ULT25NEU was developed specifically for transporting temperature-sensitive biologic products, including applications in regenerative medicine, cell therapy, clinical trials, and advanced therapeutics where maintaining ultra-low temperatures throughout transport is essential.
How is the portable freezer tested before shipment?
Every refurbished Stirling Ultracold ULT25NEU is inspected and performance tested by American Instrument Exchange technicians to verify pull-down performance, temperature stability, Stirling engine operation, alarm functionality, and both AC and DC power operation before shipment.
What is the Stirling ULT25NEU used for?
The Stirling ULT25NEU Portable Ultra-Low Freezer is designed for portable ultra-low temperature storage of sensitive materials such as:
Biological samples (DNA, RNA, vaccines)
Clinical trial materials
Cell and gene therapy products
Pharmaceutical and diagnostic samples
It is lightweight and can plug into a variety of power soruces. This makes it especially suited for cold-chain transport and remote storage applications.
What are the installation requirements?
Minimal setup is needed for this unit, meaning deployment is quick and easy. All you need it a standard electrical outlet or DC source, adequate ventilation, and a stable surface or transport mount. Beyond that, no special facility infrastructure is required.
CLICK HEREto see the Stirling ULT25NEU portable ultralow freezer on our YouTube channel
Testing Procedures for Used and Refurbished Ultralow Freezers Ensure -80°C Stability and Critical Sample Protection
Used and refurbished ultralow freezers from American Instrument Exchange are rigorously tested to ensure reliable long-term storage at temperatures as low as -80°C. Each unit undergoes a detailed inspection, full system evaluation, and extended runtime testing to meet the high standards required by research, clinical, and biorepository environments.
Why Testing Used Ultralow Freezers Is Essential
Before an ultralow freezer is placed back into service, it must be carefully tested for:
• Temperature stability and uniformity at ultralow levels (e.g., -70°C to -86°C)
• Cascade refrigeration system functionality and compressor health
• Seal and insulation effectiveness to prevent thermal loss
• Electrical safety, alarm functionality, and system compliance
Thorough testing helps prevent temperature excursions and equipment failure—crucial for protecting sensitive materials such as biological samples, vaccines, enzymes, and research specimens.
Our structured ULT testing protocol ensures each refurbished unit delivers dependable performance and long-term reliability.
Key Testing Procedures for Refurbished and Used Ultralow Freezers
1. Initial Visual Inspection
• Inspect external cabinet, hinges, and door gaskets for wear, corrosion, or damage
• Check power cords, plugs, and control interfaces for signs of wear or tampering
• Verify that internal racks, shelving, and chamber components are intact and operational
2. Functional Startup and Control Testing
• Power on the unit and confirm successful initialization of digital displays and alarm systems
• Test control panels, keypad responsiveness, and user-setpoint functionality
• Verify that door seals close tightly and form a secure barrier
3. Temperature and -80°C Stability Testing
• Test and evaluate internal temperature sensors thermometers/probes
• Monitor temperature performance at multiple chamber points over extended runtimes
• Confirm uniformity and stability at key setpoints, including -70°C, -80°C, and -86°C
4. Refrigeration System and Cascade Compressor Evaluation
• Test dual-stage (cascade) compressor function, startup times, and cycling behavior
• Evaluate evaporator coils, heat exchangers, and vacuum insulation panels for performance and integrity
• Check for refrigerant leaks, low-pressure faults, and abnormal compressor noise
5. Alarm and Safety System Verification
• Test high/low temperature alarms, power failure alerts, and battery backup systems (if equipped)
• Verify lockout controls, alarm delay settings, and door-open indicators
6. Final Quality Assurance and Documentation
• Run a continuous multi-day test cycle at -80°C to confirm sustained performance
• Document temperature logs, controller accuracy, and compressor behavior
• Complete a detailed service report
Dependable Performance from American Instrument Exchange
All refurbished ultralow freezers from American Instrument Exchange are tested to exacting standards for performance, safety, and reliability. With our rigorous inspection and testing procedures, you can trust your ULT freezer to deliver consistent -80°C storage from day one—ideal for research, clinical, pharmaceutical, and biobanking applications.
Repair and Refurbishment Protocol for Used Ultralow Freezers -80°C Storage Performance from American Instrument Exchange
At American Instrument Exchange, every used ultralow temperature freezer (ULT freezer) undergoes a rigorous, multi-step refurbishment protocol designed to restore reliable -80°C performance. Whether upright, chest-style, or undercounter, our refurbished ULT freezers are tested and restored to deliver the cold storage precision required for biological samples, vaccines, enzymes, and other temperature-sensitive materials.
Why Choose a Refurbished Ultralow Freezer from American Instrument Exchange?
• Fully tested for -80°C cold storage stability and compressor performance
• Backed by a warranty
• A cost-effective alternative to expensive new ULT units
• Environmentally responsible through equipment reuse and waste reduction
• Serviced by experienced technicians specializing in laboratory-grade refrigeration
Every ultralow freezer sold by American Instrument Exchange is carefully evaluated and restored through the following process:
1. Initial Intake & Inspection
• Exterior inspection for dents, corrosion, or physical damage
• Evaluation of door seals, hinges, and internal chamber components
• Documentation of missing parts or components requiring repair
2. Cleaning and Decontamination
• Comprehensive interior and exterior cleaning using non-abrasive cleaners
• Removal of dust, frost buildup, and residual contaminants
• Decontamination of all internal surfaces and removable parts like shelves and drawers
3. Mechanical and Electrical Repairs
• Replacement or repair of worn or damaged components (door latches, hinges, gaskets, etc.)
• Inspection and repair of control boards, displays, sensors, and switches
• Electrical system evaluation, including fuses, wiring, relays, and connectors
4. Ultralow Refrigeration System Assessment
• Testing of dual-stage compressors and cascade cooling system
• Evaluation of heat exchangers, evaporator coils, and vacuum insulation panels
• Inspection for refrigerant leaks, low pressure, or signs of compressor fatigue
• Verification of thermal insulation integrity
5. Temperature and Performance Testing
• Testing of internal temperature sensors and controllers
• Multi-point testing to verify chamber temperature uniformity at -80°C
• Long-duration, multi-day operational testing to ensure sustained ultralow performance
6. Safety and Compliance Checks
• Electrical safety testing and grounding verification
• Alarm function tests for high/low temperature alerts and power failure warnings
7. Final Quality Control and Documentation
• Multi-day runtime validation at -80°C
• Recording of temperature logs, compressor cycle data, and performance benchmarks
• Final inspection and service/testing report completed
Trust the Experts at American Instrument Exchange
With over 50 years in the lab equipment industry, American Instrument Exchange is your trusted source for refurbished ultralow freezers. Our certified refurbishment protocol ensures each ULT freezer delivers the precision, performance, and reliability your lab needs—at a fraction of the cost of new equipment.
Warranty Information
All used equipment sold by American Instrument Exchange is refurbished/reconditioned, tested to meet specifications, cleaned, and comes with a 90-day warranty from the date of shipment unless otherwise specified. New products include a warranty from the manufacturer. Your warranty is only valid if you have paid your invoice. If your invoice is over 30 days old, warranty work will not be performed until your invoice is paid in full. American Instrument Exchange is not liable for any special or consequential damages that result from the use of, or the inability to use, the materials on this site or the performance of the products,
Exceptions include international sales and items that are agreed to be sold with a lesser warranty or items that are agreed to be sold “as is.”
Should there be visible shipping damage to packaging or concealed shipping damage to item(s) supplied, buyer must communicate such damage to the delivering entity or carrier upon receipt first and to American Instrument the same day item is accepted / signed for. Failure to do so voids warranty. Customer decision to involve / procure third party or OEM service other than American Instrument or AIE assigned vendors to resolve in-warranty instrument failure or defect without first placing a service call to American Instrument voids warranty.
Return & Cancellation Policy
American Instrument Exchange will authorize the return of and issue a full refund for any equipment that is not working as represented and could not be replaced or repaired to the customer’s satisfaction by AIE or a representative of AIE during the warranty period. Returns without prior authorization and an RMA number will not be accepted.
Customers are responsible for proper packaging of the equipment and all included accessories. American Instrument will pay for insurance and shipping costs. Non-inventory items bought specifically to fill customer orders may possibly be returned, but on a case by case basis.
Customers who cancel orders after refurbishing has begun or after delivery where there are no equipment performance issues may be subject to a Restocking/Cancellation Fee of 20% or more and responsible for shipping costs for both the delivery and return.
Ongoing and Extended Support Options
American Instrument Exchange is able to provide additional repair and support services outside the warranty terms for most products that sell.
For biosafety cabinets, clean benches, chemical fume hoods, and other clean air products our team at AIE Laboratory Services can provide certifications, repairs, decontaminations, and other services for customers throughout New England, and guidance and limited technical assistance for any customers in the US and Canada for new or refurbished biosafety cabinets purchased from American Instrument Exchange.
For all other products, the repair service team at American Instrument Exchange can provide both field and depot repair evaluations. We can easily schedule and coordinate the pick-up and transportation of your malfunctioning equipment. By offering hourly rates lower than most OEM service providers and eliminating travel time for technicians, we help reduce repair costs. Furthermore, our lab depot repair service minimizes or eliminates scheduling delays. Our experienced service technicians are qualified to restore your equipment to factory specifications.
Yes, all equipment from American Instrument Exchange comes with a warranty. Used/reconditioned/refurbished equipment is tested to make sure it operates to the manufacturer's specifications and comes with a 90-day warranty (unless otherwise noted). New equipment comes with a warranty from the manufacturer.
How do you test and recondition the equipment?
Testing requirements vary across all the equipment categories we sell. Temperature controlled units are tested with NIST traceable probes and data loggers. Gaskets, external housing, glass, handles, controls and control screens are all thoroughly inspected for integrity and functionality. We test all equipment using the manufacturer's parameters and specifications to confirm that the unit operates properly.
How do products ship from American Instrument Exchange?
We can ship products both nationally and internationally using a well-established network of transporters. Smaller items will ship via UPS. Larger equipment will be palletized and shipped either LTL or air-ride, depending on the specific equipment and/or delivery requirements.
Return and order cancellation policy
American Instrument Exchange will accept the return of any product that is not working as represented and could not be replaced or repaired to the customer's satisfaction during the warranty period. Customers who cancel orders after refurbishing has begun will be subject to a cancellation and restocking fee of between 20% and 40%.
Are discounts available for educational or non-profit institutions, or for bulk purchases?
Yes – call or email us today with a list of equipment you're looking for and we can potentially put together a quote that includes a discount.
How does your price matching policy work?
We strive to keep our pricing competitive and reasonable. If you find comparable items for sale at a lower price from other vendors please send us a link and or quote for the item and we'll do our best to match or beat the price.
Can I see the equipment in person before committing to a purchase?
Customers are welcome to make an appointment to view equipment in our warehouse. Given our workload we may not be able to test or clean the equipment prior to your arrival if you have not committed to an order.
1023 Western Avenue is a working warehouse, not a showroom, and customers should dress appropriately and wear closed toe shoes.
Can I ship products that I purchased elsewhere to American Instrument for repair?
Yes – please see our repair services page for more information.
