Relative Humidity

 

Relative Humidity

 

 

Relative humidity is the amount of moisture carried in a sample of air, compared to the total amount of moisture that the sample can absorb at the same temperature and pressure.

Cooling down air that contains a certain amount of moisture will increase the relative humidity, and once it reaches 100% condensation will occur.

Try to express all this with numbers:

75ºF ambient air at 50%RH (fairly dry) contains 65 grains of water/lb of dry air

57ºF air at 60%RH contains only 39 grains of water/lb of dry air

  • in other words although we are increasing the humidity level to 60% we have to get rid of 65-39=26 grains of water for every pound (14 cu ft) of air.
  • For a 500 bottle cabinet this would be 1lb of water condensed for every 70 air changes, or in case of a small 400 cu ft custom built wine cellar, 1 lb at every 10 air changes. Of course if the cabinet or cellar is built and sealed properly this levels will not be achieved, but a heavy door usage or some small openings can lead to dramatic results:
  • Our more powerful units can circulate up to 200 CFM (cubic feet of air per minute) resulting in 3 lbs of water to be condensed hourly if ambient air leaks are constant.

In conclusion, please take all the recommendations of the manual very seriously, and in case you have a humid ambient consider from the beginning a way to drain and collect the accumulating condensation.