An arrangement for heat transport used for thermally insulating, or cooling, one or several elements. A casing is arranged to enclose a medium having heat-storing or cooling capacity. The casing has an internal space for receiving the element or elements and the medium with the medium surrounding the element or elements. The arrangement includes guides arranged in the internal space of the casing so as to guide the medium in the internal space such that a circulation and mixing of the fluid will be generated essentially throughout the internal space under the action of occurring temperature differences in the medium, whereby the natural tendency for temperature stratification of the medium is counteracted or eliminated. A corresponding method, the use of an arrangement for protecting a subsea installation or a part thereof from cooling, and use of an arrangement for efficient cooling an electrical appliance.