Water and electricity production
Air diagram of Mollier or psychrometric diagram
- It makes it possible to simplify calculations at the time of problem involved in the air-conditioning or with processes having parameters in connection with humidity of air.
- On X-coordinate is reproduced the temperatures.
- moisture (in gram of water per Kilogramme of air) is announced on y-axis (right-hand side) Knowing that moisture represents part of the pressure of air called partial pressure, It is represented on y-axis (right-hand side)
- The saturated vapour pressure is the pressure in correspondence with a temperature for a quantity of gram water/kg to air given, in such way that air cannot contain more eau(correspondent to 100% of moisture). Beyond, of condensation materializes in the form of droplet.
- It is possible to arrive to 100% of moisture, either by bringing the partial pressure to the saturated vapour pressure, or by cooling air until at the dewpoint (temperature of saturation) Plus air will be cooled below the dewpoint plus air will be dehumidified. If one divides the saturated vapour pressure of half, one decreases his relative humidity by 2 (50%). It is thus possible for us to trace lines of relative humidity.
- we consider that water Enthalpie. The heat of evaporation will be withdrawn from the mixture without changing enthalpy (until to 100% of moisture) total. An application consists in cooling air by water vaporization. air measures water jusqu?au pressure not saturation thanks to a contribution of latent heat. The temperature limits reached to 100% is called wet temperature or wet bulb.
- In reality, dehumidification and fall in temperature do not occur in two times. To know from when dehumidification occurs a new parameter was set up: If one wishes to decrease the temperature and moisture, the delta of enthalpy corresponding to the delta of temperature is called the requirement in significant refrigerating power, the delta of enthalpy corresponding to the delta of moisture is called the requirement in latent refrigerating power.
The significant power divided by the refrigerating total power reveals the cosine of an angle which represents the slope by which dehumidification occurs. This slope is called significant factor of heat (SHF = sensitive heat factor)
