Hi All,
I am modeling DOE Prototype Medium Office with Displacement Ventilation, Air-to-air Heat Exchanger, Economizer, LowTemperatureRadiant:Electric for zone heating, and one AHU per floor. For displacement ventilation, I have One Node Displacement Ventilation models for the perimeter zones and Three Node Displacement Ventilation models for the core zones since the E+ documentation states that the latter ones should not be used for zones with high external loads. I have set up (or I hope I did) the controls so that there is only the minimum outdoor air flow rate supplied to the zones during heating since max SAT is 68 F and all the heating is provided by the LowTemperatureRadiant:Electric. My problems with the model are errors such as: CheckWarmupConvergence: Loads Initialization, Zone="PERIMETER_BOT_ZN_1 ZN" did not converge after 25 warmup days; SimHVAC: Exceeding Maximum iterations for all HVAC loops (which occurs 153 times) HeatExchanger:AirToAir:SensibleAndLatent "HEAT EXCHANGER AIR TO AIR SENSIBLE AND LATENT 1": Average air volume flow rate is <50% or >130% warning continues; and HeatExchanger:AirToAir:SensibleAndLatent "HEAT EXCHANGER AIR TO AIR SENSIBLE AND LATENT 1": Unbalanced air volume flow ratio exceeds 2:1 warning continues. In addition, the primary air flow increases to the cooling design max rate even though the zone thermostat temperature is below the heating setpoint of 69.8 F (See the images below).