The photovoltaic solar assisted loop heat pipe system/heat-pump (PV-SALHP/HP) is the combination of solar assisted loop heat pipe system (SALHP) and solar assisted heat pipe (SAHP). A photovoltaic/thermal (PVT) evaporator and condenser could be shared by two circling modes

and so is the working medium. The loop heat pipe mode will be utilized when solar radiation is strong and the temperature of working medium in PVT evaporator is higher than that in condenser. Correspondingly

the heat pump mode will be started when solar radiation is weak or the temperature difference of working medium in PVT evaporator and condenser cannot satisfy the condition of loop heat pipe mode. The loop heat pipe mode is passive and the heat pump mode is active

which means that the loop heat pipe mode does not consume work and the heat pump mode does. Therefore

the transformable mode of system could heavily reduce power consumption

raise the utilization ratio of solar energy

and promote energy saving. A PV-SAHP/LHP test rig is built. The instantaneous and daily performance of the loop heat pipe mode and heat pump mode is studied.