Manufacturers Best Practice Guide
Central HVAC System: Key Strategies
Industrial HVAC Energy Use Conditions
The goals for HVAC in industrial and manufacturing facilities differ markedly from other building types in that protecting materials and products, particularly in spaces such as data centers, clean rooms and laboratories, is often more important than human comfort. Some factors influencing climate control and air quality requirements include:
- Protection of raw materials and finished products that might be temperature sensitive, such as fresh produce or wine
- Production processes and equipment that add to cooling loads, such as boilers, motors, and compressors
- Conversely, process cooling that chills ambient air
- Opportunities to recover waste heat from equipment to heat air and water
- Air quality (i.e., filtration and ventilation) requirements for sensitive materials, such as semiconductors or biological products
Industrial and manufacturing facilities also tend to have structural elements that affect indoor temperatures and air quality. Quite often, these facilities are designed as high bays, creating a large volume of air that is extremely expensive to condition. Even in low bay buildings, open, box-like layouts are common, making it challenging to break up the space into zones that can be more easily controlled. Both low-bay and high-bay buildings typically are constructed using dense building materials, such as concrete, that increase thermal mass and make it cooler in the summer and warmer in the winter.
Besides adding to cooling loads, process equipment also emits pollutants that must be safely vented outdoors, some of which must also be filtered to comply with air quality regulations. The HVAC system plays an important role safeguarding human health in these environments.
Each business will have unique needs, depending on location, size, industrial processes, equipment operations and materials and products stored. A manufacturer without perishable goods, for example, might get by with nothing more than ventilation fans in the summer and personal space heaters in the winter. On the other end of the spectrum, biomedical research facilities may require heavy-duty heating, ventilating, air conditioning and refrigerating equipment for both cold storage and clean rooms.
Actions to improve the efficiency of industrial HVAC systems:
- Be sure that HVAC efficiency activities are part of an integrated, building-wide efficiency plan
- Conduct an energy audit on the HVAC system
- Have a qualified engineer tune-up HVAC equipment for maximum optimization
- Keep your HVAC system clean and well maintained
- Make sure that the building envelope is secure and that windows, doors and ventilation systems do not leak air
- Retrofit lighting and install an energy management system
- Make sure fans, motors, pumps and compressors are operating at maximum efficiency
- Use exhaust fans sparingly
- Upgrade or replace chillers, fans and motors with more efficient models, if possible
- Adjust air duct registers
- Install energy management systems and programmable thermostats for zone control
- Utilize outside air for cooling
- Investigate ways to capture and reuse waste heat from production processes
- Use personal space heaters to warm workers instead of central HVAC, especially in high-bay facilities
- If possible, install variable air volume fans and variable speed control motors in the HVAC system
- Use an economizer to pre-cool the building in the evening and the early morning hours
Leading by Example: Cisco Systems
Cisco has made major HVAC upgrades at its San Jose campus, including installing variable-frequency drive (VFD) chillers in numerous buildings and upgrading controls. Projects completed by Cisco Systems in 2006 will cut energy use by over 14,000,000 kWh (3.6%) of electricity and 100,000 therms of natural gas annually, resulting in over $1,500,000 in cost savings.