Variable Conductance Thermal Management Technology

The Navy seeks a technology that dynamically adjusts the thermal conductivity (variable conductance) between a sensor and its environment to assist in maintaining a stable temperature with minimal power draw. Thermal management of critical electronics and sensors will involve a thermal path through solid materials before heat can be exchanged with the ambient environment. Solid materials are characterized by nearly constant thermal conductivity over temperature ranges on the order of 100░C and therefore have nearly constant thermal conductance over a given length scale. An ideal interface material will have variable conductance so that it conducts heat very well when the device must be cooled and conducts poorly when heat loss from the device should be minimized. Thermal switches exist that toggle between highly conductive states and ōopenö states where heat flow is essentially zero. Rapidly toggling between these two binary states can effectively mimic continuously variable conductance, but at the expense of nearly continuous power drawing actuation. Triton systems proposes to develop a material whose thermal conductance can be continuously varied by changing its length by increasing or decreasing a compressive force. A factor of 8 variation has been demonstrated. The effect is fully reversible and repeatable over multiple cycles. The material is easily synthesized and is readily shaped by standard machining operations so that it can conform to unusual shapes. Triton has also identified an actuation technology to apply the compressive force that continues to apply a force even when the power is turned off. Combining these approaches will achieve the NavyÆs objective to maintain stable sensor temperatures with minimal power draw. During Phase I Triton completed a feasibility assessment that addressed the 10 performance items listed in the Topic description and developed a design specification and conceptual design to be built in Phase II. Proof-of-principle will be demonstrated in Phase II through a rigorous test program and manufacturability assessment.