Utilizing Economizers Increases Cost Savings and Performance in Cold Climates
HVAC Economizers
In regular cold weather climates or locations with extreme cold temperature seasons, HVAC systems are more prone to fail, operate ineffectively, and use more energy to run. These HVAC inefficiencies cause greater wear on the HVAC system and increase costs for business owners and facility managers alike. HVAC economizers create efficiency in your HVAC unit operation, reducing energy consumption, thereby reducing the burden on the HVAC system and reducing operating costs.
Why Outdated HVAC Systems Increase Costs
Often, commercial and industrial buildings and facility spaces have outdated HVAC systems that do not perform optimally. These inefficiencies can cause your HVAC system to increase its energy consumption to maintain your regular environment temperature, also increasing the wear on the system to keep up with increased energy demands. Your inefficient and older HVAC system could be costing you much more than you realize, while also posing health risks to those working in the building by circulating dirty air. If you’ve seen your energy bills steadily increase over the years, that may be a signal of an inefficient HVAC system that needs to be upgraded.
How Economizers Increase HVAC Performance in Cold Climates
Economizers are devices connected to an HVAC system that control and reduce energy consumption, optimizing performance, particularly in colder environments. Economizers incorporate the colder air of the surrounding environment into the HVAC system instead of solely utilizing mechanical cooling, thereby reducing operating costs, system wear, and energy consumption.
Economizer best practices for cold climates:
- Use return air enthalpy compared to outside air enthalpy to enable the economizer
- Control the outside air damper to maintain the supply air setpoint minus 2°F (allows for fan heating)
- Use an outside air temperature reset schedule to modify the modulation range of the economizer as the outside temperature drops to provide control stability at all outside air temperatures
- Modulate the return air damper (reversed) with the outside air damper
- Modulate the relief air damper with a 10-20% offset to provide building positive pressure
- Monitor the mixing box performance (0-100%) and adjust the return air fan speed to maintain the performance above 90%
- Verify that the following conditions are met. If not, generate an alarm and fall back to a dry bulb to enable or disable the economizer:
- Outside air temperature sensor is valid
- Outside air humidity sensor is valid
- Return air temperature sensor valid
- Return air humidity sensor is valid
- Outside enthalpy value is valid
- Return enthalpy value is valid
- Mixed air temperature sensor is valid
- Supply air temperature sensor is valid
- Outside damper feedback matches command +/- 5%
- Relief damper feedback matches command +/- 5%
- Return damper feedback matches command +/- 5%
- Mixing box performance is above 70%
- Mixed air calculated temperature is within 5°F of the actual temperature
- When in 100% economizer the supply air sensor is within +/-5°F of the mixed air sensor
- When in startup mode with the outside air damper closed, the return air sensor, mixed air sensor, and supply air sensor are within +/-5°F
- When the unit is off, ensure the mixed air sensor is within +/- 15°F of the supply and return sensors
A properly performing economizer has the potential to save significant cooling energy. Whereas, an improperly performing economizer has the potential to waste significant heating energy or even cause property damage.
Proud Partner of ExactLogic
HumeraTech is proud to partner with our sister company, ExactLogic, to develop economizer controllers to ensure your HVAC system operates efficiently and to full capacity. Our ExactLogic economizer controllers, EXL01812 and EXL01613, have the built-in features listed above to maximize your energy savings, reducing your costs and keeping your equipment performing at the highest levels.
Is it time to upgrade your HVAC system? Contact us today!