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Method to characterize a thermal diode in saturated steam atmosphere

: Maier, Lena Maria; Hess, Tobias; Kaube, Alexandra; Corhan, Patrick; Fitger, Andreas; Bachmann, Nora; Schäfer-Welsen, Olaf; Wöllenstein, Jürgen; Bartholomé, Kilian

Postprint urn:nbn:de:0011-n-5930195 (1.9 MByte PDF)
MD5 Fingerprint: 293f9b2395ea8f1652572606c68abeae
Copyright AIP
Erstellt am: 11.6.2020

Review of scientific instruments 91 (2020), 6, Art. 065104, 14 S.
ISSN: 0034-6748
ISSN: 1089-7623
Bundesministerium fur Wirtschaft und Energie BMWi (Deutschland)
03ET1478A; MagMed
Entwicklung einer kältemittelfreien und effizienten Kühltechnik
Zeitschriftenaufsatz, Elektronische Publikation
Fraunhofer IPM ()
Thermal Diode; measuring method; Heatpipes

We present a novel measurement method for the characterization of thermal diodes in a saturated steam atmosphere. A measuring setup has been developed in which two pressure sensors are integrated. Using a developed analytical model, the heat flow, the volume flow, and the cracking pressure are determined from the measured absolute pressures and the pressure difference. The analytical model was verified using a flow through an orifice. We first calculated the volume flow through the orifice, with a diameter of 3 mm, using the Reader-Harris equation and then compared it to experimentally determined values. The experimentally determined values showed a discrepancy of 9%. With the measurement setup, we have characterized a check valve developed for magnetocaloric heat pumps, which has a thermally rectifying behavior. The developed check valve consists of three spring arms, which are radially attached to a valve disk. The heat flow through the check valve in the forward direction is 166 W for water, 239 W for ethanol, and 547 W for methanol at a temperature difference of 1 K. In the reverse direction, the heat flow is −0.03 W at a temperature difference of −1 K. For methanol, this corresponds to a rectification coefficient of more than 18 000.