Exploration Study – Industrial Ventilation Systems
Auto assembly line paint shop achieves $210,000 in annual ventilation cost savings with $20,000 investment.
CHALLENGE: TO DETERMINE THE OPPORTUNITY FOR ENERGY REDUCTION IN THE VENTILATION SYSTEM
An automotive paint shop assembly line has a continuous ventilation system with the purpose to scrub powdered coating particulate from the building air. The existing fans had variable frequency drives but were uncontrolled (set at 100%). The car volumes were varying due to various process reasons including product mix and order demand.
A process energy exploration study based on measurement and modeling was conducted with the plant operation managers to determine the feasibility for energy conservation.
Process energy modelling using regression analysis confirmed that there was significant waste energy reduction available by measuring particulate levels with sensors and adding fan speed controls.
SOLUTION: REALIGN THE VENTILATION CONTROL TO THE BEST DRIVER
Ventilation systems are designed to remove excess heat, contaminants, particulate, odours, etc. for the purpose of health and safety or process needs. Generally, HVAC systems in manufacturing facilities are designed for worse case scenarios. Operating plants don’t always run to capacity or worst case. An opportunity exists to vary the capacity of the ventilation system to match the actual plant conditions.
For this plant, it was found that the powdered coating particulate levels varied with paint production rate. Therefore, it was decided to try controlling the speed of the ventilation fans based on a predetermined setpoint, the quality standard for particulate level. Process energy modelling confirmed that there was significant opportunity for waste energy reduction by measuring particulate levels with sensors and adding a controller for fan speed adjustment. As a result, particulate level sensors and controls were deployed with 30% savings in ventilation consumption.
An investment in sensors and controls of $20,000 resulted in the plant saving $210,000/year in fan drive energy consumption. Fortunately, VFD’s were already in place and the project CAPEX required was modest.
- 30% Reduction in annual consumption
- $20,000 Investment in Sensors and Controls
- $210,000 /year in fan drive energy consumption savings