McCarty R.,Marlow Industries Inc.
Journal of Electronic Materials | Year: 2010
A recent investigation into thermoelectric phenomenon under large temperature differences, such as a thermoelectric cooler (TEC) at no-load, maximum- temperature-drop conditions (ΔT max), has raised questions about the simplified approach that assumes constant material properties. The accuracy of the simplified approach can be improved by using material properties averaged over the relevant temperature range by integration, creating a quasi-constant material property solution. A one-dimensional (1-D) numerical solution, with fully temperature-dependent material properties, of a typical Bi 2Te 3 TEC operating from an elevated ambient temperature under no-load, ΔT max conditions yielded a cold-side temperature nearly 8°C lower than the quasi-constant material property solution. This same cooler was modeled in ANSYS, providing a full three-dimensional (3-D) thermoelectric solution that matched the 1-D numerical solution within 0.6°C. With further investigation, it was found that more than half of the difference between the temperature-dependent numerical and quasi-constant material property solutions was due to the Thomson effect term, and most of the remaining error was due to temperature-independent electrical resistivity approximations. It was found that the error due to the temperature-independent thermal conductivity approximation was negligible. Experimental results for a 24-couple TEC further confirm the accuracy of the numerical model with temperature-dependent material properties. © 2010 TMS.
McCarty R.,Marlow Industries Inc.
Journal of Electronic Materials | Year: 2013
There is a significant amount of literature that discusses thermoelectric power generator (TEG) design, but much of it overly simplifies the design space and therefore the results have limited use in designing real-life systems. This paper develops a more comprehensive model of the thermal and electrical interactions of a TEG in a system with known hot-side and cold-side thermal resistances and corresponding constant system temperature differential. Two design scenarios are investigated for common TEG system applications. In one method, the power from a TEG is maximized for a given electrical load, simulating a case where the TEG is electrically in series with a known load such as a fan. In the second design scenario, the power from a TEG is maximized for a given electrical load resistance ratio, n (the ratio between the external load resistance and the internal TEG resistance), simulating an application where the TEG is electrically in series with a load-matching converter. An interesting conclusion from this work is that, in the first design scenario, the electrical load resistance ratio, n, that maximizes TEG power occurs at √1+ZT (where ZT is the thermoelectric figure of merit) instead of 1 as reported previously in literature. Equally interesting is that, if you define an analogous thermal resistance ratio, m′ (representing the ratio between the TEG thermal resistance at open-circuit conditions and the system thermal resistance), the maximum power in both design scenarios occurs at √1+ZT instead of the commonly cited value of 1. Furthermore, results are presented for real-life designs that incorporate electrical and thermal losses common to realistic TEG systems such as electrical contact resistance and thermal bypass around the TEG due to sealing. © 2012 TMS.
Marlow Industries Inc. | Date: 2011-12-01
In one embodiment, a method for forming a metallized ceramic includes thermal spraying metal directly onto a first side of a ceramic plate. The metal comprising aluminum. The method also includes densifying the thermally ceramic plate after spraying the metal onto the first side of the ceramic plate.
Marlow Industries Inc. | Date: 2013-07-30
A system and method is provided for controlling condensation generation in an air conditioning system for use in a bed (mattress). During active operation of the air conditioning system to generate conditioned air, the relative humidity of ambient air is measured and operation of one or more thermoelectric devices (TEDs) within the air conditioning system in response to the measured relative humidity is adjusted to control condensate buildup. In addition, during a subsequent drying operation, the relative humidity of the ambient air is measured and the drying operation is adjusted or otherwise controlled based on the measurement.
Marlow Industries Inc. | Date: 2011-05-31
A distribution system is adapted for use with a mattress and a personal comfort system with an air conditioning system operable for outputting a conditioned air flow. The distribution system includes at least top and bottom layers of fabric material and a spacer structure disposed between the bottom and top layers. The spacer structure defines an internal volume within the distribution layer and is configured to enable the received conditioned air flow to flow therethrough. This flow of conditioned air has a cooling or heating effect on a body on the mattress.