Loop heat pipe (LHP) is an efficient two-phase heat transfer device

mainly applied to spacecrafts and terrestrial electronics with high heat density. The existing flat loop heat pipes (FLHPs) are only used a surface to dissipate heat. Thus

the adverse back-conduction makes it difficult for FLHPs to startup at low heat loads

and also

the another surface of the flat evaporator possesses the potential for heat rejection. Aiming at the disadvantages above

a methanol-copper loop heat pipe with a bifacial evaporator was developed in this paper. Under the conditions of assisted-gravity angle at 10° and heat sink temperature at 0℃

startup performance and variable heat load operation were investigated with one surface heated and two surfaces heated simultaneously. The experimental results indicated that this loop could start up successfully and operate normally when one surface or two surfaces worked

but startup process with two surfaces heated showed faster and more stable. With heat source simulator wall temperature below (90±2)℃

the evaporator with one surface heated could transfer the maximum heat load of 210 W

corresponding to a heat flux of 21.8 W·cm-2

while 240 W at the evaporator with two surfaces heated. For operation with alternative heat load

the LHP could quickly shift from one surface to another surface

and operation failure was not observed.