Revision history [back]

1. The HVAC systems are simulated in their full glory to calculate the end-use utility numbers. Consult the HVAC equipment inputs to determine nominal efficiencies which are typically then adjusted using curves for off-design operation.

2. Columns 1 and 2 are for zone HVAC equipment (fancoil, PTAC,PTHP, etc.). Columns 3 and 4 are for air terminal units supplied from an air loop (AirLoopHVAC). The underlying output variables which feed this report are documented in detail in the Input Output Reference, search for "Sensible Heat Gain Summary." However these particular columns (1-4) are not quite clear, because the original report only had two columns for "HVAC Input Sensible Air Heating" and Cooling. When these were split between zone equipment and air loop equipment, apparently the documentation was not updated to match.

3. As mentioned in the I/O Reference overview for this report "positive values are shown as additions and negative values are shown as removal for most variables." Running some example files shows that the two cooling columns generally show negative values, except an annual run of HVACTemplate-5ZoneFanCoil-DOAS.idf does have a positive value for "HVAC Zone Eq & Other Sensible Air Cooling" for Space5-1. So it appears there is a problem with the method for splitting the total HVAC impact between zone equipment and air loop. I can't say for sure, but my guess is that the sum of the first four columns is correct as shown and the positive values belong in the heating column.

Found the problem in the source code. The zone equipment contribution is not being separated every time step, but the split is being done at the end of the simulation: ZoneEqCooling = NetHVACCooling - AirTerminalCooling. Likewise for heating. So, over the course of the year, the DOAS air terminals are overcooling the zones and the zone equipment is providing heating to offset the overcooling.

Issue #6794 posted to correct the documentation and fix the positive "cooling" values.