1. Optimize Ventilation Exhaust Air
Each 1000 CFM of ventilation requires about one kilowatt of electric load. For winter heating in Wisconsin each unnecessary CFM of ventilation in a round-the-clock operation costs about a dollar per year.
Steps
To optimize your plant ventilation systems:
1. Create a list of all ventilated workstations.
2. For each workstation determine the ventilation requirement according to regulations and your facility’s standards.
3. For each ventilation point have the actual ventilation rate measured by a qualified ventilation service company.
4. If you have identified excessive ventilation reduce exhaust airflows by improving ventilation hood and baffle design. If airflow reduction is more than 20 percent of rated ventilation fan capacity, reduce fan speed and rebalance the system. You can reduce fan speed by changing pulley wheel sizes in belt-driven systems, installing a variable-speed drive on direct-drive fans, installing an adjustable speed coupling on direct-drive systems, and replacing the existing motor with a lower-speed or multiple-speed motor. Replacing the entire fan/motor assembly is also an option. Remember that whenever you reduce total ventilation airflow or adjust one or more ventilation hoods, you must rebalance the system. ! If ventilation requirements at a workstation vary, then vary the ventilation rate to match the need. You can shut down the ventilation when unnecessary or vary the ventilation rate to match changing needs. To reduce the amount of ventilation needed: cover idle tanks, improve hood and baffle designs, and identify mist suppressant options. Hire a firm that specializes in this if you do not have the expertise available.
2. Minimize Cost of Winter Space Heating
1. Identify and evaluate sources of waste heat (cooling towers, refrigeration condensers, compressed-air cooling water) that could be used for space heating in winter and switched back to external discharge in summer.
2. Identify areas of your facility that regularly get large volumes of cold air (mechanic bays, loading docks, garage doors). Ask your equipment supplier to evaluate the benefit of installing infrared heating in these areas.
3. If any part of your facility relies on electric space heaters consider replacing them with heaters powered by natural gas, propane, steam, or waste heat. These generally have lower operating costs than electric heaters, which can make replacement economically favorable.
4. If parts of your facility are regularly unoccupied, evaluate using setback thermostats to reduce the space temperature when unoccupied. This is possible for all types of heating systems including steam: when a thermostat turns off the fan, steam supply to unit heaters is shut off as well.
5. When high ceiling areas are occupied in winter use ceiling fans to bring down warm air.
3. Minimize Heat Loss in Process Tanks
You can reduce energy costs by minimizing heat loss through the walls and open tops of heated process tanks:
1. Cover tanks whenever possible with a rigid or floating cover.
2. Consider using automated covers if frequent opening is required.
3. Insulate tanks with at least one inch of insulation.
4. Perform maintenance to minimize scale buildup on heating elements.
4. Agitate Tank Fluids Using Lowest Cost Method
Metal finishing tank fluids are typically agitated with compressed air. Compressed air is the highest cost utility in an industrial plant, five times more expensive than electricity to produce the same work. Replacing compressed air agitation with either “blower air” agitation or circulation pumping will significantly reduce the cost of agitating tank liquids.
5. Minimize Heating Cost in Drying Stations
Drying stations remove moisture from parts as they exit the plating line. You can reduce costs in three areas: reduce the amount of heat used to dry each part; insulate walls of the drying station to prevent heat from escaping; and use the lowest cost energy source to provide the heat.
6. Optimize Facility Lighting
Optimize Facility Lighting You can reduce lighting costs by using more efficient lighting technologies and by reducing unnecessary lighting.
1. If your fluorescent lights do not have electronic ballasts and T-8 (1 inch diameter) bulbs, contact a lighting supplier or consultant to evaluate the economics of replacing your lighting system with a newer, more efficient system.
2. Identify periods when lighting remains on when not needed for production or safety. Quantify the number of fixtures and number of hours of unnecessary lighting. Contact a lighting supplier or consultant to evaluate the economics of installing automatic switching controls, which can turn lighting off when an area is unoccupied.
3. Identify any outdoor lighting that is on during the day and install a photosensor to control this lighting.
4. If you have any mercury vapor high bay or outdoor lights, contact a lighting supplier or consultant to evaluate the economics of installing metal halide fixtures with the same light output.
7. Minimize Losses in Electrical Power Supply System
If electrical conductors are undersized or their connections have air or corrosion gaps in them, some of the electricity is converted to heat and lost. In AC to DC power rectifiers, if the conversion process is not proceeding correctly they produce less DC electricity and more heat. The following new design and maintenance practices minimize these losses
References