Emerson VSSG, VSG manual Installation, One Fan Diameter

Section 3 • Installation

General Installation Guideline for Multiple Air Coolers Installed in a Common Area

calculations for each guideline. Let’s assume the follow- ing coolers are being installed in a common area:

•Cooler 1 - 7’ wide x 10’ long with a 6’ fan moving 55,000CFM of air. Face velocity is 785FPM.

•Cooler 2- 8’ wide x 12’ long with a 7’ fan moving 72,000CFM of air. Face velocity is 750FPM.

NOTE

This general installation guideline applies to all air coolers on site, whether if they are supplied by or not supplied by Vilter.

The purpose of this guideline is providing design infor- mation when multiple air cooled heat exchangers are installed in a common area. There are two main focal points of this guideline. One area is free flow area which addresses how much free area is required to prevent air flow “starvation” of the units. The second item provides a guideline as to how multiple air cooled heat exchang- ers should be arranged to minimize the potential of hot air recirculation due to the environment.

•Cooler 3- 10’ wide x 16’ long with a 9’ fan moving 120,000CFM of air. Face velocity is 750FPM.

ONE FAN DIAMETER

In order to keep the leg height of the installation to a minimum we want to install the coolers at least 1 fan di- ameter from the nearest obstruction. Referring to Figure 3-10, the nearest obstruction is the building.

Based on the information above, the largest fan diame- ter in the installation is 9ft. Therefore, the coolers should be placed at least 9’ away from the building.

INTAKE VELOCITY

FREE FLOW

There are two basic guidelines that we follow to address free flow area when multiple designs are being installed in a common area.

•Air coolers should be placed at least 1 fan diameter away from the nearest obstruction. This is based on the largest fan diameter in the bay of coolers.

•Intake area to the air cooler should have an intake velocity equal to or below 500FPM as the as the dis- charge velocity is above 500FPM.

We will look at each rule and provide pictorials and

Based on the information above, we are going to solve for the leg height that will provide an intake velocity of 500FPM. We know the following:

•The total airflow of the installation is 247,000CFM

•We have an intake perimeter of 82’ for all 4 sides based on the cooler placement.

•Our intake velocity guideline is 500FPM

PREFERRED

TOTAL INTAKE PERIMETER = 82 FEET

Figure 3-10. Installation of Coolers - One Fan Diameter Next to Building

3 – 12 VSG/VSSG • Installation, Operation and Maintenance Manual •Vilter/Emerson • 35391SSG