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Gravity dependence quantifiers for vapor compression cycles subjected to inclination testing and parabolic flights.

Number: 2343

Author(s) : BRENDEL L. P. M., CASKEY S. L., BRAUN J. E., GROLL E. A.

Summary

Increased utilization of vapor compression cycles for spacecraft is foreseen due to the relatively high COPs compared to alternative technologies for food refrigeration and air-conditioning. However, system level publications about effects of microgravity on a vapor compression cycle are still very scarce. Over the course of a NASA Small Business Innovation Research project, data was collected from one vapor compression cycle that was exposed to both inclination testing on-ground and microgravity maneuvers in-flight while operating continuously. Different quantifiers were introduced and developed to compare seven datasets differentiated by the type of gravity perturbations and refrigerant. All gravity perturbations affected the measurements, but the responses were often difficult to classify, let alone quantify. The most useful quantifier identified was the MIN/MAX-measure, capturing the span of values measured due to a gravity perturbation (maximum minus minimum). This quantifier identified a decreasing gravity dependence as a function of increasing mass flux across all datasets. Depending on the cycle mass flux, gravity induced changes of the evaporation temperature were in a range of 1 to 10 K, whereas the evaporator heat transfer rate varied by up to +/-50% and as little as +/-2%. Generally, the collected datasets show inclination changes cause stronger cycle responses than parabolic flight maneuvers.

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  • Original title: Gravity dependence quantifiers for vapor compression cycles subjected to inclination testing and parabolic flights.
  • Record ID : 30030669
  • Languages: English
  • Subject: Technology
  • Source: 2022 Purdue Conferences. 19th International Refrigeration and Air-Conditioning Conference at Purdue.
  • Publication date: 2022

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