Add placeholder for new enumeration

design/FY2025/AddMultiSpeedWaterToAirCoilChoicesforDesuperheater.md

@@ -0,0 +1,96 @@
+# Add More Coil/WaterHeater Choices for Coil:WaterHeating:Desuperheater
+
+
+**Yueyue Zhou**
+
+**National Renewable Energy Laboratory**
+
+**Feb 10, 2025**
+
+
+## Justification for New Feature ##
+
+Desuperheater is a widely used new technology making use of waste heat from HVAC system to heat domestic hot water. Desuperheater is available in E+ only supporting 
+a very limited amount of HVAC systems and water heater tanks, while the most widely used occasion for desuperheater: ground source heat pump system is only available for single speed water-to-air coils.
+It constrained the variations people modeling their hybrid systems and impeded the promotions of using this new energy efficiency techonology. 
+Users and interface developers are requesting EnergyPlus broaden its capability of modeling desuperheater with multi-speed water-to-air coils.
+Since EnergyPlus already supports some systems, it would be more straight-forward to add more enumarations to EnergyPlus.
+
+
+## Overview ##
+
+EnergyPlus would be modified to add more enumarations in Coil:WaterHeating:Desuperheater object's heating source object type fields.
+
+## Approach ##
+
+EnergyPlus already handles HVAC/water heating hybrid systems for several coil types. The workflow is straight-forward to add the same structure as those systems. The steps to new enumarations are given below.
+
+
+1. IDD file modification: **Coil:WaterHeating:Desuperheater** A9 add **Coil:Cooling:WaterToAirHeatPump:VariableSpeedEquationFit**. 
+
+2. Available reclaimed heat data passing: The available waste heat, heat source name and type data is spread across three namespaces (DataHeatBalance, WaterThermalTank, and the corresponding 
+HVAC coil namespace). Arrays and structures added to pass data. The same method that the quantity of available heat is delivered from HVAC loop while doesn't impact compressor performance by limiting its 
+reclaiming efficiency factor (would be discussed if the assumption is acceptable). 
+=======
+1. IDD file modification: See below the entire list of **Coil:WaterHeating:Desuperheater** modified field:
+
+```
+Coil:WaterHeating:Desuperheater,	   
+  A9 , \field Heating Source Object Type
+       \required-field
+       \type choice
+       \key Coil:Cooling:DX
+       \key Coil:Cooling:DX:SingleSpeed
+       \key Coil:Cooling:DX:TwoSpeed
+       \key Coil:Cooling:DX:TwoStageWithHumidityControlMode
+       \key Coil:Cooling:DX:VariableSpeed
+       \key Coil:Cooling:DX:MultiSpeed
+       \key Coil:Cooling:WaterToAirHeatPump:EquationFit
+       [Add]\key Coil:Cooling:WaterToAirHeatPump:VariableSpeedEquationFit
+       \key Refrigeration:CompressorRack
+       \key Refrigeration:Condenser:AirCooled
+       \key Refrigeration:Condenser:EvaporativeCooled
+       \key Refrigeration:Condenser:WaterCooled
+       \note The type of DX system that is providing waste heat for reclaim.
+```
+
+
+2. Available reclaimed heat data passing: The available waste heat, heat source name and type data is spread across three namespaces (DataHeatBalance, WaterThermalTank, and the corresponding 
+HVAC coil namespace). Arrays and structures added to pass data. The heat relcaim from water cooled HVAC system would 
+cause decreasing of the heat transferred to the condenser plant loop thus impact the HVAC performance. Therefore, the 
+reclaimed heat would be passed back to HVAC water coil namespace and be substracted from the total source heat in the loop to reflect the impact. 
+
+
+3. Reclaimed heat calculation: The calculation of reclaimed heat is coded in WaterThermalTank namespace, the same approach as other available systems. 
+
+
+## Testing/Validation/Data Sources ##
+
+Existing EnergyPlus test files would be modified to produce models that utilizes multi-speed ground source heat pump systems, stratified/mixed tanks.
+
+## Input Output Reference Documentation ##
+
+The documentation of **Coil:WaterHeating:Desuperheater** inputs will be modified to reflect the new enumarations.
+
+## Input Description ##
+
+**Field: Heating Source Object Type**
+
+Would add valid enumarations for multi-speed water-to-air cooling coils.
+
+## Outputs Description ##
+
+No need to add more outputs
+
+## Engineering Reference ##
+
+Engineering reference would be checked to make sure it documents all the options
+
+## Example File and Transition Changes ##
+
+New enumarations would be enabled in object **Coil:WaterHeating:Desuperheater**
+
+## References ##
+
+
+

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

@@ -5144,6 +5144,8 @@ \subsubsection{Overview}\label{overview-10}
 
 Coil:Cooling:WaterToAirHeatPump:EquationFit
 
+Coil:Cooling:WaterToAirHeatPump:VariableSpeedEquationFit (This option is added in the IDD in preparation for full implementation. It is currently not implemented.)
+
 Refrigeration:CompressorRack
 
 Refrigeration:Condenser* (multiple objects)
@@ -5157,7 +5159,7 @@ \subsubsection{Overview}\label{overview-10}
 \begin{itemize}
 \item Coil:WaterHeating:Desuperheater
 \item WaterHeater:Mixed or WaterHeater:Stratified
-\item Coil:Cooling:DX:* or Refrigeration:CompressorRack or Refrigeration:Condenser:* or Coil:Cooling:WaterToAirHeatPump:EquationFit
+\item Coil:Cooling:DX:* or Refrigeration:CompressorRack or Refrigeration:Condenser:* or Coil:Cooling:WaterToAirHeatPump:EquationFit or Coil:Cooling:WaterToAirHeatPump:VariableSpeedEquationFit
 \end{itemize}
 
 A schematic diagram showing the desuperheater water heating coil with its water heater and DX system condenser is shown below.

doc/input-output-reference/src/overview/group-heating-and-cooling-coils.tex

@@ -5190,6 +5190,8 @@ \subsubsection{Inputs}\label{inputs-22-000}
   \hyperref[coilcoolingdxvariablespeed]{Coil:Cooling:DX:VariableSpeed}
 \item
   \hyperref[coilcoolingwatertoairheatpumpequationfit]{Coil:Cooling:WaterToAirHeatPump:EquationFit}
+\item
+  \hyperref[coilcoolingwatertoairheatpumpvariablespeedequationfit]{Coil:Cooling:WaterToAirHeatPump:VariableSpeedEquationFit} (This option is added in the IDD in preparation for full implementation. It is currently not implemented.)
 \item
   \hyperref[refrigerationcompressorrack]{Refrigeration:CompressorRack}
 \item

idd/Energy+.idd.in

@@ -57725,6 +57725,7 @@ Coil:Cooling:WaterToAirHeatPump:VariableSpeedEquationFit,
         \reference CoolingCoilsWaterToAirVSHP
         \reference-class-name validBranchEquipmentTypes
         \reference validBranchEquipmentNames
+        \reference DesuperHeatingWaterOnlySources
    A2,  \field Water-to-Refrigerant HX Water Inlet Node Name
         \required-field
         \type node
@@ -60893,6 +60894,7 @@ Coil:WaterHeating:Desuperheater,
        \key Coil:Cooling:DX:VariableSpeed
        \key Coil:Cooling:DX:MultiSpeed
        \key Coil:Cooling:WaterToAirHeatPump:EquationFit
+       \key Coil:Cooling:WaterToAirHeatPump:VariableSpeedEquationFit
        \key Refrigeration:CompressorRack
        \key Refrigeration:Condenser:AirCooled
        \key Refrigeration:Condenser:EvaporativeCooled