Merge pull request #11452 from NatLabRockies/coil-cooling-dx-crankcase

Fix crankcase energy for Coil:Cooling:DX when part of air-to-air heat pump is not ignored

Author: mitchute

doc/engineering-reference/src/simulation-models-encyclopedic-reference-001/coils.tex

@@ -1135,7 +1135,7 @@ \subsubsection{Model Description}\label{model-description-2-004}
 
 \(\dot{Q}_{cap,crankcase}\) is the crankcase heater capacity (W).
 
-If this cooling coil is used as part of an air-to-air heat pump (Ref. AirLoopHVAC:UnitaryHeat-Pump:AirToAir), the crankcase heater defined for this DX cooling coil is disregarded and the associated output variable is omitted. Instead, the crankcase heater defined for the DX heating coil (Coil:Heating:DX:SingleSpeed) is enabled during the time that the compressor is not running for either heating or cooling. In this instance, RTF in the above equations would be the runtime fraction of the heat pump's heating coil or cooling coil, whichever is greater.
+If this cooling coil is used as part of an air-to-air heat pump (e.g., AirLoopHVAC:UnitaryHeatPump:AirToAir, AirLoopHVAC:UnitarySystem, or ZoneHVAC:PackagedTerminalHeatPump), the crankcase heater defined for this DX cooling coil is disregarded and the associated output variable is omitted. Instead, the crankcase heater defined for the DX heating coil (e.g., Coil:Heating:DX:SingleSpeed) is enabled during the time that the compressor is not running for either heating or cooling. In this instance, RTF in the above equations would be the runtime fraction of the heat pump's heating coil or cooling coil, whichever is greater.
 
 In addition to calculating the total cooling capacity provided by the DX air conditioner, it is important to properly determine the break down of total cooling capacity into its sensible (temperature) and latent (dehumidification) components. The model computes the sensible/ latent split using the rated SHR and the ADP/BF approach (Carrier et al. 1959). When the DX coil model is initially called during an EnergyPlus simulation, the rated total capacity and rated SHR are used to calculate the coil bypass factor (BF) at rated conditions. The rated total capacity and rated SHR are first used to determine the ratio of change in air humidity ratio to air dry-bulb temperature:
 
@@ -2070,7 +2070,7 @@ \subsubsection{Speed 1 Operation}\label{speed-1-operation}
 
 The main reason using the above approach is that outlet conditions are calculated in the same way in low and high speed operation.
 
-The crankcase heater defined for this DX cooling coil is enabled during the time that the compressor is not running for either heating or cooling. The crankcase heater power use from either heating or cooling is reported in the heating coil (Coil:Heating:DX:MultiSpeed).
+The crankcase heater defined for this DX cooling coil is enabled during the time that the compressor is not running for either heating or cooling. The crankcase heater power use from either heating or cooling is reported in the heating coil (e.g., Coil:Heating:DX:MultiSpeed).
 
 \subsubsection{Higher Speed Operation}\label{higher-speed-operation-000}
 
@@ -3732,7 +3732,7 @@ \subsubsection{Heating Operation}\label{heating-operation-000}
 
 \({Q_{cap,crankcase}}\) is the crankcase heater capacity (W).
 
-If this heating coil is used as part of an air-to-air heat pump (Ref. AirLoopHVAC:UnitaryHeat-Pump:AirToAir), the crankcase heater defined for this DX heating coil is enabled during the time that the compressor is not running for either heating or cooling (and the crankcase heater power defined in the DX cooling coil object is disregarded in this case). In this instance, RTF in the above equations would be the runtime fraction of the heat pump's heating coil or cooling coil, whichever is greater.
+If this heating coil is used as part of an air-to-air heat pump (e.g., AirLoopHVAC:UnitaryHeatPump:AirToAir, AirLoopHVAC:UnitarySystem, or ZoneHVAC:PackagedTerminalHeatPump), the crankcase heater defined for this DX heating coil is enabled during the time that the compressor is not running for either heating or cooling (and the crankcase heater power defined in the DX cooling coil object is disregarded in this case). In this instance, RTF in the above equations would be the runtime fraction of the heat pump's heating coil or cooling coil, whichever is greater.
 
 The properties of the air leaving the heating coil at full-load operation are calculated using the following equations:
 
@@ -4153,7 +4153,7 @@ \subsubsection{Speed 1 Operation}\label{speed-1-operation-1}
 
 The main reason for using the above approach is that outlet air conditions are calculated in the same way for all operating speeds.
 
-The crankcase heater defined for this DX heating coil is enabled during the time that the compressor is not running for either heating or cooling. The crankcase heater power use from either heating or cooling is reported in the heating coil.
+The crankcase heater defined for this DX heating coil is enabled during the time that the compressor is not running for either heating or cooling. The crankcase heater power use from either heating or cooling is reported in the heating coil (e.g., Coil:Heating:DX:MultiSpeed).
 
 \subsubsection{Higher Speed Operation}\label{higher-speed-operation-2}
 

doc/input-output-reference/src/overview/group-coil-cooling-dx.tex

@@ -103,7 +103,7 @@ \subsubsection{Inputs}\label{inputs-02}
 
 \paragraph{Field: Crankcase Heater Capacity}
 
-This numeric field defines the crankcase heater capacity in Watts. When the outdoor air dry-bulb temperature is below the value specified in the input field Maximum Outdoor Dry-bulb Temperature for Crankcase Heater Operation (described below), the crankcase heater is enabled during the time that the compressor is not running. If this cooling coil is used as part of an air-to-air heat pump (Ref. AirLoopHVAC:UnitaryHeatPump:AirToAir or PackageTerminal: HeatPump:AirToAir), the crankcase heater defined for this DX cooling coil is ignored and the crankcase heater power defined for the DX heating coil (Ref. Coil:Heating:DX:SingleSpeed) is enabled during the time that the compressor is not running for either heating or cooling. The value for this input field must be greater than or equal to 0, and the default value is 0. To simulate a DX cooling coil without a crankcase heater, enter a value of 0.
+This numeric field defines the crankcase heater capacity in Watts. When the outdoor air dry-bulb temperature is below the value specified in the input field Maximum Outdoor Dry-bulb Temperature for Crankcase Heater Operation (described below), the crankcase heater is enabled during the time that the compressor is not running. If this cooling coil is used as part of an air-to-air heat pump (e.g., AirLoopHVAC:UnitarySystem or ZoneHVAC:PackagedTerminalHeatPump), the crankcase heater defined for this DX cooling coil is ignored and the crankcase heater power defined for the DX heating coil (e.g., Coil:Heating:DX:SingleSpeed) is enabled during the time that the compressor is not running for either heating or cooling. The value for this input field must be greater than or equal to 0, and the default value is 0. To simulate a DX cooling coil without a crankcase heater, enter a value of 0.
 
 \paragraph{Field: Crankcase Heater Capacity Function of Temperature Curve Name}
 
@@ -681,8 +681,16 @@ \subsubsection{Outputs}\label{outputs-01}
 \item HVAC, Average, Cooling Coil <Fuel> Rate {[}W{]}
 \item HVAC, Sum, Cooling Coil <Fuel> Energy {[}J{]}
 \item HVAC, Average, Cooling Coil Runtime Fraction {[]}
+\end{itemize}
+
+If not part of a heat pump (if part of a heat pump, crankcase heater is reported only for the heating coil):
+
+\begin{itemize}
 \item HVAC, Average, Cooling Coil Crankcase Heater Electricity Rate {[}W{]}
 \item HVAC, Sum, Cooling Coil Crankcase Heater Electricity Energy {[}J{]}
+\end{itemize}
+
+\begin{itemize}
 \item HVAC, Average, Cooling Coil Air Mass Flow Rate {[}kg/s{]}
 \item HVAC, Average, Cooling Coil Air Inlet Temperature {[}C{]}
 \item HVAC, Average, Cooling Coil Air Inlet Humidity Ratio {[}kgWater/kgDryAir{]}