In the atomizing humidifier (Figure 6), the water goes through a rotating basket designed to generate very small and uniform-size droplets.
Tables 4 and 5 show the same information for eight tests performed on the centrifugal atomizing humidifier. Table 4 includes, in this case, information about the supply and exhaust mass flow rates during the process, considering the operation conditions of this system.
For the centrifugal atomizing humidifier, the average difference is 7.6%, with a standard deviation of 3.8%, taking into account the water mass flow rate measurement errors and the fact that some part of the water remains liquid in the air, the test bench walls, and demisters.
As example of the validation process, the model parameters are identified separately by using the experimental tests carried out with both humidifier systems tested in this study (five for wetted media humidifier and eight for centrifugal atomizing humidifier) and the EES software (Klein and Alvarado 2001) by minimization of the error function [theta], which depends on the relative errors of air humidity ratio and temperatures at the humidifier exhaust.
For the centrifugal atomizing humidifier, the model errors are presented in Table 8.
Centrifugal Atomizing Humidifier Model Errors Average Standard Error Deviation W, -0.17 0.12 [g.sub.water_vapor]*[kg.sub.dry_air.sup.-1] [t.sub.a, ex,] -0.011 0.020 K ([degrees]R) (-0.19) (0.036) Minimal Maximal Deviation Deviation W, -0.3 0.03 [g.sub.water_vapor]*[kg.sub.dry_air.sup.-1] [t.sub.a, ex,] -0.25 0.41 K ([degrees]R) (-0.45) (0.74) Confidence Limits W, -0.087 [g.sub.water_vapor]*[kg.sub.dry_air.sup.-1] -0.25 [t.sub.a, ex,] 0.0028 (0.005) K ([degrees]R) -0.025 (-0.05) The average perceptual difference between experimental and predicted values of the air humidity ratio is [+ or -]2.3%.