I mean perfectly insulated like vaccum^^ (yeah you loose heat for the first 100+ cycles but just a small amount to heat the pipe till it reachs the liquid temperature)   Keep in mind, that there are some cases where no heat will be transferred cause of the "minimun" energy needed. => So i testes 300K Oxygen at 2Kg vs 370K water and there is NO heating of the oxygen even after 100 cycles (Best non abysalite insualted pipes would be igneous rock and these pipes heat the oxyg