Another method most commonly employed is the reduction of moisture in the air by means of reducing the temperature. By examination of the dew point alone or saturation curve on the psychrometric chart. It can readily be seen that as the temperature of the air is lowered, the amount of moisture it can hold is reduced considerably. Thus by cooling the air below the dew point, the moisture contained in that air can be condensed out and some of the moisture vapour removed in liquid form, but cooling to very low temperature makes the refrigeration process impractical, as it requires a great deal of subsequent re-heating. The reduction in air temperature is also limited by the freezing point of water condensing on the cooling coil, which in some designs is offset by complicated brine spray and liquid lithium chloride type systems available using a combination of refrigeration and adsorbent liquid. These are very bulky and involve complicated control systems for the proper maintenance of solution density.