Best Practice Guide

Food and Beverage Growers and Processors

Central HVAC System

Optimization

Thermostat settings
In the winter, try setting the thermostat to the lowest point necessary, usually about 68ºF depending on stored products, operations, and local climatic conditions. Investigate ways to capture and reuse waste heat from production processes, or consider using personal space heaters to warm workers instead of central HVAC, especially in highbay facilities.

In summer weather 90ºF or less, you might be able to get by just running a dehumidifier and relying on natural ventilation from open windows, doors, or bays. When conditioned air is needed, set thermostat to the highest temperature possible while still staying comfortable, usually about 78ºF.

Programmable thermostats help automate this task, and can save up to 25 percent on heating and cooling costs. For more information, see Flex Your Power's product guides on programmable and automatic thermostats.

Zone control
The mark of an efficient HVAC system is that it only runs in areas where people actually are - nobody needs a conditioned conference room that sits empty. If a building is sparsely populated during off-hours like nights and weekends, HVAC operations should be scaled back or shut off completely. Again, programmable thermostats help automate this task.

Some HVAC systems allow zone control. Each zone is controlled by a separate thermostat that signals dampers to open and close as needed to deliver conditioned air only to occupied work areas, not to empty offices, vestibules, storage areas, or other unoccupied spaces.

Automation and optimization
An optimized HVAC system runs dynamically, with each piece of major equipment operating in careful coordination. Air quality and temperature are maintained within set parameters, using the least amount of energy necessary.

To do this, a building must be equipped with:

  • An HVAC system.
  • Controls on major equipment, such as compressors, fans, and dampers.
  • An energy management system (sometimes referred to as a building automation system or enhanced automation).

In addition to equipment, optimization requires quality engineers with the knowledge and experience to configure the entire system. Engineers monitor equipment and operations over a period of time, thoroughly test equipment, and then make recommendations to management about possible upgrades. As the entire system is fine-tuned, major components are tested and balanced to work in close coordination. Although new equipment sometimes needs to be installed, the focus of this work is to improve the performance of existing equipment. In cases where activities within a building have changed since the initial installation - say an area once used as offices now houses a data center - yearly professional reviews can ensure optimization and efficiency.

Optimization takes time and a sizeable investment, but typically results in very quick payback (sometimes less than a year), substantial energy and cost savings, and greatly improved indoor air quality.

Careful optimization seeks to catch these mistakes and lost opportunities. Engineers monitor equipment and operations over a period of time, thoroughly test equipment, and then make recommendations to management about possible upgrades. Although new equipment sometimes needs to be installed, the focus of this work is to improve the performance of existing equipment. As the entire system is fine-tuned, major components are tested and balanced to work in close coordination. This work takes time and a sizeable investment, but typically results in very quick payback (sometimes less than a year), substantial energy and cost savings, and greatly improved indoor air quality.

Optimization has some special indirect benefits - besides lowering energy costs. Energy management systems (EMS) can control building systems other than the HVAC, such as lighting, fire and smoke detection, and security systems. This is particularly useful for companies that participate in demand response programs since energy-saving measures can be pre-programmed in advance of an electrical emergency. Besides cutting energy costs when rates are at their highest, this helps protect critical equipment

Several EMS use direct digital controls that allow managers to monitor and manipulate building systems over a secure Internet connection, enabling them to solve problems from any location. The EMS also generates reports that track energy use and equipment performance over time, providing better information flows for overall energy and facility management.
Finally, optimizing the HVAC system extends equipment life and reduces downtime for repair and maintenance. The system quickly detects when problems arise, and alerts facility staff when repairs are needed.


Resources

Roos, C. Overview: Heating, Ventilation, and Air Conditioning. Northwest Food Processors Association webpage, Building and Facility Efficiency.

Energy Star. Building Upgrade Manual. Chapter 4, Fan System Upgrades, and Chapter 5, Heating and Cooling System Upgrades.

North Carolina Division of Pollution Prevention and Environmental Assistance.
Energy Efficiency in Industrial HVAC Systems
. September 2003.

California Energy Commission.

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