4480 (RP-862) -- Energy Wheel Effectiveness Evaluation, Part I: Outlet Airflow Property Distributions Adjacent to an Energy Wheel PDF

In this paper the outlet airflow properties are measured for a typical rotary energy wheel. It was found that the air temperature, humidity, and velocity are non uniform in both the radial and angular directions adjacent to the outlet air faces of the wheel. Depending on the operating conditions and over the supply and exhaust outlet faces, the variations in temperature ranged from2ºC to 6ºC (3.6ºF to 10.8ºF), or 0.10 to 0.55 of the inlet temperature difference; variations in the relative humidity ranged from 7% to 15%; and variations in the velocity ranged from 1.0 to 2.8 m/s (200 to 550 ft/min), or 0.38 to 1.2 of the average velocity. If such variable property data are to be used to calculate effectivenesses, care must be exercised to calculate the correct bulk mean flow properties at the supply and exhaust outlets. Provided the uncertainties in the data and calculations are included, the sensible, latent, and total effectivenesses were calculated and shown to agree with the corresponding values using downstream flow station data measured according to ASHRAE Standard 84-1991R using the testing conditions for heating and cooling specified in ARI Standard 1060-2000.

Units: Dual