What you need to know about the degrees of air cooling

The degree of cooling of the air I am the main air flow must be increased both by the consumption of an auxiliary air flow and the amount of circulating water. With constant b degree of cooling of the main air flow, increases with nt growth. However, the most significant increase in the efficiency of cooling occurs to the values ​​of NT of the procedure. With a further increase in NT, the magnitude of the efficiency of asymptotically approaches the theoretical limit. For the anti -flow scheme of the heat exchanger with infinitely large transfer of the value, the value becomes equal to the theoretical limit, t. e. one. We will analyze the changes in NT values ​​for typical surface heat exchangers of local and central air conditioners, suggesting their use as the first stage of separate air conditioners of two -stage evaporative cooling. Using structural indicators of heat exchangers, we determine the weight speed of the air, believing that surface heat exchangers operate on nominal performance in the air, and the water speed in the tubes meets the optimal value, 14 m/s. The experimental formulas calculated the average heat transfer coefficients and aerodynamic resistances. The total surface of the heat exchangers of the first stage changed by a sequential increase in the number of rows and, in terms of expression, the values ​​of NT were calculated. From their analysis it is clear that the most favorable indicators of NT values ​​and aerodynamic resistances are achieved for superficial aluminum heat exchangers from local multi -zone air conditioners such as KNM, and KNM. (The structural indicators of these heat exchangers are given further. At the same time, aerodynamic resistances for steel surface heat exchangers with equal NT values ​​are much higher than for aluminum. ELF produces and implements RGB controllers of different types: ELF LEDs, LED lighting, the peculiarity of RGB systems is that they allow you to get different shades by mixing colors