Charts - Efficient Indoor Comfort

Efficient Indoor Comfort

HVAC Resources for Professionals

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Charts Idea!... print out and laminate two charts back to back for toolbag durability.
Charging and Temperature Difference Charts

Along with evaporator superheat and condenser temperatures, this chart allows you to check the evaporator airflow from the entering wetbulb temperature. Open Chart 1	Like the chart to the left, but allows you to determine the evaporator delta T range from the relative humidity. Open Chart 2

Other Charts

Superheat chart in graphical form. Open Chart 3


Although the Manual D procedure all but guarantees a duct system that will provide each room with the correct amount of air comfortably, quietly and at a low energy cost, it's often not done. More common is the "rules of thumb" and "trial and error" method.
With a variable speed blower, this guide (above right) will at least allow 400 cfm/ton across the coil . Do not rely on this guide to provide even and comfortable temperatures to each room. Without some luck, open doors, and a lot of practical experience, that only happens when using the manuals, transfer grilles and air balancing. Open Chart 4

An often over looked aspect of duct design is System Effect and Static Regain. Here's an informative article from ACHR News Extra Edition.