I'm using the HVACTemplate:Zone:PTHP template to estimate the cooling and heating loads of a AC split unit with COP of 3.29 and thermal capacity of 12000 BTU during one year and I'm getting the following warnings:
* Warning * Calculated design heating load for zone=DORM2 is zero. * ~~~ * Check Sizing:Zone and ZoneControl:Thermostat inputs. *** SizeDXCoil: Potential issue with equipment sizing for Coil:Cooling:DX:SingleSpeed DORM2 PTHP COOLING COIL * ~~~ * User-Specified Gross Rated Total Cooling Capacity [W] = 3516.00000 * ~~~ * differs from Design Size Gross Rated Total Cooling Capacity [W] = 2960.30983 * ~~~ * This may, or may not, indicate mismatched component sizes. * ~~~ * Verify that the value entered is intended and is consistent with other components. * Warning * SizeHeatingCoil: : Potential issue with equipment sizing for Coil:Heating:Electric DORM2 PTHP SUPP HEATING COIL * ~~~ * ...Rated Total Heating Capacity = 0.00 [W] * ~~~ * ...Capacity used to size child component set to 0 [W] *** Testing Individual Branch Integrity *** All Branches passed integrity testing *** Testing Individual Supply Air Path Integrity *** All Supply Air Paths passed integrity testing *** Testing Individual Return Air Path Integrity *** All Return Air Paths passed integrity testing *** No node connection errors were found. *** Beginning Simulation * Warning * CalcDoe2DXCoil: Coil:Cooling:DX:SingleSpeed "DORM2 PTHP COOLING COIL" - Full load outlet air dry-bulb temperature < 2C. This indicates the possibility of coil frost/freeze. Outlet temperature = 1.43 C. * ~~~ * ...Occurrence info = ANO, 01/01 00:00 - 00:05 * ~~~ * ... Possible reasons for low outlet air dry-bulb temperatures are: This DX coil * ~~~ * 1) may have a low inlet air dry-bulb temperature. Inlet air temperature = 16.999 C. * ~~~ * 2) may have a low air flow rate per watt of cooling capacity. Check inputs. * ~~~ * 3) is used as part of a HX assisted cooling coil which uses a high sensible effectiveness. Check inputs. *** Simulation Error Summary ***
*** ===== Recurring Error Summary ===== *** The following recurring error messages occurred.
*** * Warning * CalcDoe2DXCoil: Coil:Cooling:DX:SingleSpeed="DORM2 PTHP COOLING COIL" - Full load outlet temperature indicates a possibility of frost/freeze error continues. Outlet air temperature statistics follow: *** * ~~~ * This error occurred 30222 total times; *** * ~~~ * during Warmup 0 times; *** * ~~~ * during Sizing 0 times. *** * ~~~ * Max=1.999957 Min=0.6961
I believe that the first warning is not a problem once the weather file is from a very hot climate. What worries me is the third which indicates the possibility of coil frost/freeze. I believe the problem is because the constant cooling setpoint is set to 17 °C, but this is the value that I have to use. Does anyone know how I can fix this problem? are these warnings something to worry about? If someone wants to check the IDF file here it is: https://www.dropbox.com/s/xc8m9cedjgvk1oj/55162_1_Nordeste_RN__0A_s.idf?dl=0
