Eutectic Refrigeration Unit "Kooltube" is a holdover or latent heat storage system. Slient, Reliable, Economic, Fool proof! Eutectic Refrigeration Unit "Kooltube" is a holdover or latent heat storage system. The completed unit comprises a 220V single phase or 380V 3 phase condensing set coupled to eutectic beams mounted internally to the roof of the truck body. Externally,to the uninitiated,the ...