Consider a numerical example. Inside height of 6 m, where the air is not mixed, it is necessary to remove with general ventilation of 200 kg / h of moisture. Heat low, the temperature of the working area +! 8 В° C, relative humidity 70%. Moisture content of outdoor air tn =- + 10 В° C, and F = 65%
Mobile dust extractors
rf 5 g 1 kg.
For given parameters of air in the working area of the diagram d we find of3 = = 9,2 g / kg. Coefficient n - 0,65.
In the fight against moisture and fog with the filing of superheated inflow into the upper zone (PLI installing heaters in the overlap) and an extract from the upper zone of the coefficient / 7 = 1. In this case, d-> = dy, ie,. in the formulas substituted moisture content is not in the working area, and at the top.
Relative humidity in the upper zone to avoid condensation should not be taken above 80-85%. The temperature of outgoing air is largely dependent on the number of super-heated air supply and temperature from overheating. Both are calculated m the heat balance, taking into account heat generation and heat loss, as well as the cost of heat for evaporation of fog and the overheating of water vapor. The latter value is very uncertain, as it is difficult to establish, in particular, how much moisture condenses and turns into fog. In addition, the condensation of water vapor with the formation of fog is allocated a certain amount of heat.
It is possible to make the calculations, which condenses and turns into the fog about 30% of the total released in the indoor humidity. Heat coming into the air by condensation, partially dispersed, and you can take it into account in an amount not exceeding 50%. Then the heat consumption for the dissolution of the fog type 1 kg of moisture will be released
0,15-630: s-100 kcal / kg.
Recalculate the previous example, provided that the 200 kg / h of steam released from the mirror boiling bath. Heat in the room will take 10 000 kcal / h, the heat losses 30,000 kcal / h. Inlet air of 50% is fed into the work zone with S / P = + 18 В° C. The rest of the air is fed into the upper zone of superheated.
To maintain thermal balance we need to introduce heat: the heat loss compensation
30000 - 10000 - 20000 kcal / h for evaporation fog formed
200-100 = 20 000 kcal / h;
20 000 -1-20 000 = 40 000 kcal / h.
Calculation of air exchange in the fight against vlagovydeleniyami is the most unfavorable to the transition period, ie, when the outside temperature of +10 В° C. Relative humidity of outdoor air is taken equal to 60-65% - resulting air is usually preserved for the winter period until the outside temperature, under rules for the design of ventilation systems, the parameters of A.