Heat Cycle

Choosing a heater that provides either mechanical makeup air or recirculated air can affect the efficiency and outcome of your heating application. The diagrams below outline the two methods and offer some insight into the benefits and challenges faced with each type of heat cycle.

Mechanical Makeup Method

Mechanical Makeup Method

  1. Fresh warm makeup air is mechanically introduced into the area from the heater.
  2. Warm air rises to the upper level of the building.
  3. Seeking equilibrium with the cool air outside, the warm air leaves the building.
  4. Warm air that escapes through the upper level of the building is replaced by mechanically introduced makeup air from the heater.
  5. Mechanically controlled air exchanges flush moisture that results from by-products of the combustion process.
  6. The building envelope, the means by which the building “breathes,” determines how much warm air can escape through the upper level; the tighter the envelope, the less mechanically introduced makeup air is necessary.
  7. Humidity levels usually stabilize between 35% and 45% RH. The SMACNA and ASHRAE humidity thresholds are 60% RH.
  8. With lower humidity levels and scheduled flush outs, this system creates a clean indoor air quality (IAQ)
  9. The building, including all structural components, reaches equilibrium at the desired temperature.

Recirculation Method

Recirculation Method

  1. Warm air is introduced into the area directly from the heater.
  2. Warm air rises to the upper level of the building.
  3. Warm air seeks equilibrium with the cool air outside
  4. The building envelope, made up of small openings around doors and windows, allows the building to “breathe” and the warm air to escape.
  5. Warm air from the heater continues to be introduced and mixed with air throughout the building via fans.
  6. Heat loss is decreased because fans run continuously to regulate air temperature, and the system detects when to start and stop the combustion cycle.
  7. Buildings with tighter envelopes may call for dehumidification equipment depending on the humidity requirements of the building standards or codes.

If you would like to know more about the heat cycles outlined here or your options for implementing a mechanical makeup or recirculation system from Tioga, contact us.