Ventilation under the joint allocation of heat and moisture
With considerable heat haze - education is not observed. In some areas of the premises where the specific heat for some reason reduced the ability of local fog formation. In such cases, the zone of low heat release should be considered in isolation from the rest of the room. Ventilation of the "cold" zones is solved on the basis of anti-fog, ie, by filing a superheated flow in the upper band.
Principles of ventilation in the joint allocation of heat and moisture are the same as if there is only water. Also widely used local shelters and pumps, and ventilation is most often mixed. General exchange and mixed ventilation implemented a "bottom - up" or "top - up". Inflow submitted to the working and upper zone scattered or concentrated sprays.
If at low heat and no flow of superheated temperature in the upper area of the room is only slightly different from the temperature of the zone, then at high heat picture changes dramatically. Thermal spray rise to overlap and form beneath the heat and humidity "cushion" to the parameters of air, significantly different from the parameters of the air operations area. The temperature difference in the working and upper zones in the absence of stirring more striking than in the presence of only heat. This is explained by the higher roof insulation wet plants. This is true only if the room does not form local centers of fogging and there is no dissolution of fog with warm air at the ceiling.
At high values of h] is of the order of 1500-2000 should always use the natural temperature increase on the height of the room. From this perspective, the supply air flow concentrated streams can sometimes be disadvantageous.
Defining the air when general ventilation should be considered with the parameters of air in the upper zone, and not working. To calculate the air, using the above formula (47), should take the coefficient n equal to 1, and the moisture content of the outgoing air d2 is calculated from its parameters in the upper zone.
When coupled with the allocation of heat and moisture parameters of supply and outgoing air are linked humid - heat balance. At high values of the slope ap humidity exhaust air is nearly always much lower than permitted by the sanitary norms. In other words, the main criterion for determining the parameters of the outgoing air is not moisture, and temperature.
That is why special importance definition gud. It can be applied to an empirical formula (43) using a temperature gradient of A, whose values can be taken to the limits stated above. Not recommended for use in calculating the value of A greater than 1.
To determine the gut, using the coefficients m (see В§ 14), should not more so, that almost does not matter m for wet plants. As in the struggle with the heat, to determine exactly gud only possible by experiment. If there is evidence that indeed the observed temperatures in similar shops, the best they have and use. But unfortunately, these data are extremely scarce and often use the old formula with a temperature gradient.