Experimental study of flat-disk loop heat pipe with R1233zd(E) for cooling terrestrial electronics

Abstract

• A flat evaporator made of aluminum alloy was designed for ground applications. • R1233zd(E), an eco-friendly refrigerant, was selected as the working fluid. • The LHP could dissipate the heat of 190 W with an effective length of 790 mm. • The thermal performance was stable even at heat sink temperature of 30 °C. • The minimum LHP thermal resistance was 0.197 °C/W at 0 °C heat sink temperature. Flat evaporator loop heat pipes with good thermal performance and compact volume have been widely used in electronic device applications. A flat-disk evaporator loop heat pipe made of aluminum alloy was designed for terrestrial application in this paper. R1233zd(E) was selected as the working fluid for its ultra-low toxicity and environmentally friendly. The pumping force of the system, driving the working fluid circulation, was generated by the sintered capillary wick made from nickel powder. Considering the requirements for electronics and the capillary limit of the wick together, the target temperature was below 75 °C and the effective heat transfer length was set as 790 mm. With a heat sink temperature of −10 °C, it could dissipate the heat of 190 W (11.43 W/cm 2 ). The performance investigation under bad external conditions was also carried out. A relatively broad operating range between the heat load of 10 W (0.60 W/cm 2 ) and 130 W (7.82 W/cm 2 ) was observed with a 30 °C heat sink temperature. However, slight temperature overshoot occurred during the start-up test but the system was able to self-regulate and stabilize quickly. Moreover, the variable heat load test, imitating the heat-dissipating demand for actual electronic devices, demonstrated that this system responded fast and operation failure did not happen. The minimum thermal resistance of the evaporator and the total LHP was 0.134 °C/W and 0.197 °C/W, respectively.