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A Self-Regulating Freezable Heat Exchanger for Spacecraft

Award Information

National Aeronautics and Space Administration
Award ID:
Program Year/Program:
2013 / STTR
Agency Tracking Number:
Solicitation Year:
Solicitation Topic Code:
Solicitation Number:
Small Business Information
TDA Research, Inc.
CO Wheat Ridge, CO 80033-1916
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Woman-Owned: No
Minority-Owned: No
HUBZone-Owned: No
Phase 2
Fiscal Year: 2013
Title: A Self-Regulating Freezable Heat Exchanger for Spacecraft
Agency: NASA
Contract: NNX13CJ46C
Award Amount: $687,217.00


A spacecraft thermal control system must keep the vehicle, avionics and atmosphere (if crewed) within a defined temperature range. Since water is non-toxic and good for heat transport, it is typically used as the coolant that circulates within the crew cabin boundary. This loop then interfaces with another low freeze point fluid, such as ammonia, for transport of heat to a radiator where the temperatures can be considerably below the freezing point of water. The volumetric expansion during freeze usually prevents its use in external systems since freezing will damage the components. Yet, if the system can accommodate the forces generated by freezing, then selectively allowing parts of a heat exchanger to freeze can be used to passively increase the turn-down of the heat rejection from radiators. TDA Research, Inc. has been developing freezable water/ice phase change heat exchangers for several years that offer several advantages: they can eliminate the need for a separate heavy Freon or ammonia loop; use the buildup of ice to regulate the rate of heat transfer, and the endotherm of melting ice can absorb peak loads from the spacecraft to reduce the size and mass of the radiator. Therefore, TDA Research and the University of Colorado set out to demonstrate a lightweight and freeze tolerant water/ice heat exchanger to passively regulate the heat rejection rate from the water coolant loop of a manned spacecraft to its heat sink systems. The heat exchanger has no actively moving parts and is thus extremely reliable. In Phase I, we designed and built a self-regulating freezable heat exchanger that we put through 191 freeze/thaw cycles without damage and it has the capability to transfer the loads expected in crewed spacecraft. In Phase II, we will design, build and test a large-scale freeze tolerant water/ice heat exchanger that forms the heart of a thermal control system that we will deliver to NASA.

Principal Investigator:

Robert A. Copeland
Principal Investigator

Business Contact:

John Wright
Chief Technology Officer
Small Business Information at Submission:

TDA Research, Inc.
CO Wheat Ridge, CO 80033-1916

EIN/Tax ID: 841043375
Number of Employees:
Woman-Owned: No
Minority-Owned: No
HUBZone-Owned: No
Research Institution Information:
University of Colorado at Boulder
572 UCB
Boulder, CO 80309-80309
Contact: Anselmo Serralheiro