RushCo Energy Specialists offers many services, and one of them is providing maintenance agreements to clients to ensure the proper preventive work is being performed on valuable assets. Consultants claim that up to 30% of a building’s value is in the cooling and heating systems. We believe it is wise to take care of these investments.

That cost does not include energy consumption, loss of productivity from failed equipment, or money required to make avoidable repairs. RushCo uncovered such a potential loss of money in a Dallas high rise in which we were providing planned maintenance on their systems.

The customer was unhappy with his first-floor air handling unit. It was noisy, hard to work on, and not moving the correct amount of air to his tenants who were complaining about high temperatures.

RES studied the issue, taking CFM, temperature, energy consumption, and noise level measurements to compare to the original design data. Based on our findings and conversations with the customer, we determined that the most important issues were the accessibility of the motor and the belts driving the blower wheel(safety issue), the noise this drive system was creating, and airflow to his tenants.

RES presented a solution that used the modern technology of a small fan array. A fan array is multiple, individual, smaller variable speed fans in a designed configuration. The benefits of a fan array include noise reduction, the elimination of belts, pulleys and a large motor turning a shaft, greater control of air flow, and reduced energy consumption.

We sized the fans to match the existing power available, the design CFM, and physical size of the air handling unit. We fabricated a metal bulkhead for the mounting of the fans, pre-fitting components in our shop, and on a beautiful Friday night, delivered all pieces to the jobsite and began our work.

We dis-assembled the existing motor and pulley arrangement, cleaned the interior of the AHU, rolled a new surface sealant on the floor, and mounted our new bulkhead. Then we mounted and wired the fans. We installed a new simple control module to vary the speed of the fans to maintain a certain static pressure. After all was in, we started the new fans and adjusted the controls. We finished the job the following day, making final adjustments.

We returned to the job site one week later with some field test equipment and confirmed our projected energy and noise reduction, and improved airflow.

Retrofitting an AHU with a fan array allows an owner to benefit from better temperature and humidity control, quieter operation, and reduced energy costs without the enormous cost of replacing the entire AHU. In many cases, the AHU cannot be replaced due to size constraints. A retrofit may be the only solution to a poor performing AHU.

If you manage or own an older AHU, and are having some of the issues described here, we would like to speak with you about possible solutions. Please be careful around your equipment and reach out if something does not seem right. We can make it better.