At what temperatures works the brine?
While liquid nitrogen (LN2) with an evaporation temperature goes down to -196 C, brine reaches only a quarter of it. The report concerns the latter technique normally using magnesium-chloride liquid. For lower temperatures calcium-chloride will be used. The cryogenic point of CaCl2 is at -55 C, while for MgCl2 results -34 C. Also kerosene would be possible, but is hardly used because of fire danger.
