Small Business Innovation Research/Small Business Tech Transfer
Vapor Compression Refrigeration System for Cold Storage on Spacecrafts
Project Description
NASA is looking for solutions for its long-term or distance food storage and transport applications. Achieving high thermal efficiencies and reliability while maintaining volumetric and mass efficiency has been the key challenge with these kinds of refrigeration/freezing systems in a microgravity environment. Previous state of the art refrigerator/freezer systems such as the ISS RFR, use thermoelectric thermal control with very low overall system COP of around 0.36 (in freezer mode).Alternatively, terrestrial cold food storage systems utilize much more efficient vapor compression thermal control systems, making the systems lighter and more compact. Currently, these systems do not have provisions to fulfill the load and reliability requirements of space applications and are also not designed for microgravity operation. An example would be Kelvinator KCCF220QW chest freezer. This freezer can maintain temperatures as low as 26͒C at COPs of around 2.2 to 2.4.Air Squared is proposing the development of a Zero-gravity Vapor Compression Refrigerator (ZVCR). The ZVCR is an oil-free, scroll driven, vapor compression food storage system that is thermally efficient, lightweight and reliable. Similar to conventional systems, the ZVCR will include four major components: compressor, condenser, expansion device and evaporator. But, instead of a heavy and oil lubricated working fluid compressor, it will use an advanced oil-free orbiting type scroll compressor and expander developed by Air Squared. Its oil-free design will remove system’s operational reliance on gravity while keeping the design compact & lightweight at higher efficiencies. For expansion work recovery, a scroll expander based on the same technology as the compressor will be used to further improve the system’s performance. Custom heat exchangers will be designed for efficient operation in microgravity while considering the size, weight and reliability requirements.
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Anticipated Benefits
Via an innovated compact scroll technology, the ZVCR transports the benefits of earth-based refrigeration and thermal control into space for long-term human exploration. Installed on ISS resupply modules, the improved COP, minimized space and weight and maximized reliability designed into the ZVCR would allow for more food and supplies to be stored on NASA missions. The reduced weight and increase payload afforded by the ZVCR would decrease fuel costs and increase mission durations for potential Mars exploration. In addition to the ZVCR space refrigeration applications, Air Squared can easily modify the system to meet a diverse set of NASA�s efficient thermal control needs. As a waste heat rejection pump, the ZVCR could provide precise thermal control for spacecraft operating at high ambient temperature locations. A larger ZVCR could efficiently control the livable environment and crew accommodations as an environmental control unit for spacecraft or stations. Regardless of electronic, cabin, or food storage thermal management, a compact, lightweight reliable, and efficient ZVCR could increase the efficiency of NASA operations.
With a compact duet scroll compressor and expander design, the reliable and efficient ZVCR is poised to impact the aerospace and aviation thermal control market. The oil-free nature of the proposed ZVCR reduces the need for oil separation and componentry within thermal systems that demand reduced size and weight in low and zero gravity environments. Implemented on board military aircraft, the ZVCR would provide excellent waste heat rejection and thermal systems control of precise atmospheric temperatures and cabin pressurization. Due to the efficient vapor compression refrigeration, the ZVCR could increase storage life, capacity, and low temperature cooling as an active container system for aviation cold transportation of food and medical supplies. The ZVCR would not rely on dry ice for refrigeration, allowing additional logistical flexibility in the event of delayed flight schedules. Reliable and efficient oil-free cooling and heating systems have substantial potential for both terrestrial and aerospace applications. More »
With a compact duet scroll compressor and expander design, the reliable and efficient ZVCR is poised to impact the aerospace and aviation thermal control market. The oil-free nature of the proposed ZVCR reduces the need for oil separation and componentry within thermal systems that demand reduced size and weight in low and zero gravity environments. Implemented on board military aircraft, the ZVCR would provide excellent waste heat rejection and thermal systems control of precise atmospheric temperatures and cabin pressurization. Due to the efficient vapor compression refrigeration, the ZVCR could increase storage life, capacity, and low temperature cooling as an active container system for aviation cold transportation of food and medical supplies. The ZVCR would not rely on dry ice for refrigeration, allowing additional logistical flexibility in the event of delayed flight schedules. Reliable and efficient oil-free cooling and heating systems have substantial potential for both terrestrial and aerospace applications. More »
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Primary U.S. Work Locations and Key Partners
| Organizations Performing Work | Role | Type | Location |
|---|---|---|---|
| Air Squared, Inc. | Lead Organization | Industry | Broomfield, Colorado |
Johnson Space Center
(JSC)
|
Supporting Organization | NASA Center | Houston, Texas |
Primary U.S. Work Locations
-
Colorado
-
Texas
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