Abstract: A heat transfer device having a working fluid capable of circulating around a fluid flow path, the circulation around the fluid flow path bringing the working fluid in and out of thermal contact with a heat source, the heat transfer device comprising: a fluid containing portion internally defining a working fluid flow path; a heat source at least partially in thermal contact with the fluid containing portion; a gas substance generator at least partially within the fluid containing portion, and arranged to generate bubbles of vapor capable of driving the working fluid along a portion of the working fluid flow path in thermal contact with the heat source; wherein, in use, the driven working fluid absorbs heat from the heat source and transports the heat away from the heat source; and the driven working fluid returns to the gas substance generator to be recycled about the fluid flow path.

Abstract: A heat transfer device having a working fluid capable of circulating around a fluid flow path, the circulation around the fluid flow path bringing the working fluid in and out of thermal contact with a heat source, the heat transfer device comprising: a fluid containing portion internally defining a working fluid flow path; a heat source at least partially in thermal contact with the fluid containing portion; a gas substance generator at least partially within the fluid containing portion, and arranged to generate bubbles of vapor capable of driving the working fluid along a portion of the working fluid flow path in thermal contact with the heat source; wherein, in use, the driven working fluid absorbs heat from the heat source and transports the heat away from the heat source; and the driven working fluid returns to the gas substance generator to be recycled about the fluid flow path.

Abstract: A solar energy converter comprising: a solar energy absorber, the solar energy absorber comprising a photovoltaic element; a heat transfer element in thermal contact with the solar energy absorber; a primary heat exchanger in thermal contact with the heat transfer element; a secondary heat exchanger; and a heat transfer control element; wherein the heat transfer control element is arranged to selectively place the secondary heat exchanger either in thermal contact with the heat transfer element or out of thermal contact with the heat transfer element.

Abstract: A heat transfer assembly comprising: an elongate envelope; an elongate heat transfer device located within the envelope, the heat transfer device having an elongate heat transfer chamber; and an elongate heat exchanger passing longitudinally through at least a portion of the elongate heat transfer chamber.

Abstract: A solar energy converter comprising: a solar energy absorber, the solar energy absorber comprising a photovoltaic element; a heat transfer element in thermal contact with the solar energy absorber; a primary heat exchanger in thermal contact with the heat transfer element; a secondary heat exchanger; and a heat transfer control element; wherein the heat transfer control element is arranged to selectively place the secondary heat exchanger either in thermal contact with the heat transfer element or out of thermal contact with the heat transfer element.

Abstract: A heat transfer device having a working fluid capable of circulating around a fluid flow path, the circulation around the fluid flow path bringing the working fluid in and out of thermal contact with a heat source, the heat transfer device comprising: a fluid containing portion internally defining a working fluid flow path; a heat source at least partially in thermal contact with the fluid containing portion; a gas substance generator at least partially within the fluid containing portion, and arranged to generate bubbles of vapor capable of driving the working fluid along a portion of the working fluid flow path in thermal contact with the heat source; wherein, in use, the driven working fluid absorbs heat from the heat source and transports the heat away from the heat source; and the driven working fluid returns to the gas substance generator to be recycled about the fluid flow path.