A heat pipe system including a heat pipe having a first end and a second end for transferring working fluid from the first to the second end, a first reservoir in fluid communication with the first end for holding working fluid in liquid form, a first heat exchanger for transmitting thermal energy from a heat source to working fluid in the first reservoir to vaporize the fluid, a second heat exchanger for transmitting thermal energy from vaporized working fluid to a heat sink thereby condensing the fluid, a return conduit and a pump for pumping the condensed working fluid along the return conduit, where the heat pipe, the return conduit and the first reservoir form a hermetically sealed circuit. A method of transferring thermal energy using a heat pipe system is also disclosed.