Coil:Cooling:DX:TwoStageWithHumidityControlMode
CoilPerformance:DX:Cooling
Used in:
- DX cooling coils in Air handling units when Two stage with dehumidification option used
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CoilPerformance:DX:Cooling
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Used in:
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The multimode DX coil is functionally equivalent to the single-speed DX cooling coil but with multiple performance modes available. It is capable of modelling two-stage DX units and units with an enhanced dehumidification mode such as coil bypass or subcool reheat. It can have up to 4 performance modes to accommodate a 2-stage 2-mode unit.
A unique user-assigned name for an instance of a DX cooling coil. Any reference to this DX coil by another object will use this name. This name is fixed and cannot be changed by the user.
The value for this input defines the number of capacity stages and must be 1 or 2. The default value is 1. Larger DX units often have two capacity stages, which are often two completely independent compressor/coil circuits with the evaporator coils arranged in parallel in the supply air stream. Two-stage operation affects cycling losses and latent degradation due to re-evaporation of moisture with continuous fan operation.
Check this option if the DX coil provides enhanced dehumidification to increase dehumidification based on a humidistat signal.
Defines the type of dehumidification control. The following options are valid for this field:
The default is 1-None. For all dehumidification controls, the max humidity setpoint on the control node is used. This must be set using a Zone humidistat and a downstream setpoint manager of type:
5-Multi zone maximum humidity average, or,
When extra dehumidification is required, the equipment may not be able to meet the humidity setpoint if its full capacity is not adequate.
The name of the schedule that denotes whether the DX cooling coil can run during a given time period. A schedule value greater than 0 (usually 1 is used) indicates that the coil can be on during a given time period. A value less than or equal to 0 (usually 0 is used) denotes that the coil must be off.
The data under this header defines the DX coil performance for stage 1 operation without enhanced dehumidification (normal mode).
The data items for Normal Mode Stage 1 Coil Performance are described under Cooling Coil - Single Speed DX coils.
The data under this header defines the DX coil performance for stage 1+2 operation (both stages active) without enhanced dehumidification (normal mode).
The data items for Normal Mode Stage 1+2 Coil Performance are described under Cooling Coil - Single Speed DX coils.
The data under this header defines the DX coil performance for stage 1 operation with enhanced dehumidification active.
The data items for Dehumidification Mode 1 Stage 1 Coil Performance are described under Cooling Coil - Single Speed DX coils.
The data under this header defines the DX coil performance for stage 1+2 operation (both stages active) with enhanced dehumidification active. An EnergyPlus CoilPerformance:DX:Cooling object is generated based on these inputs.
The data items for Dehumidification Mode 1 Stage 1+2 Coil Performance are described under Cooling Coil - Single Speed DX coils.
This numeric field defines the crankcase heater capacity (in W). 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. 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 outdoor air dry-bulb temperature (in ˚C or ˚F) above which the compressor’s crankcase heater is disabled. The value for this input field must be greater than or equal to 0°C, and the default value is 10°C.
This numeric field contains the capacity of the DX coil’s electric evaporative cooler basin heater (in W/K or Btu/h-F). This field only applies for Condenser type = Evaporatively cooled. This field is used in conjunction with the Basin Heater Setpoint Temperature described in the following field. The basin heater electric power is equal to this field multiplied by the difference between the basin heater set point temperature and the outdoor dry-bulb temperature. The basin heater only operates when the DX coil is off, regardless of the basin heater schedule described below. The basin heater capacity must be greater than or equal to zero.
This numeric field contains the set point temperature (in ˚C or ˚F) for the basin heater described in the previous field. This field only applies for Condenser type = Evaporatively cooled. The basin heater is active when the outdoor air dry-bulb temperature falls below this setpoint temperature, as long as the DX coil is off. This set point temperature must be greater than or equal to 2˚C.
This alpha field contains the name of the basin heater operating schedule. This field only applies for Condenser type = Evaporatively cooled. The basin heater operating schedule is assumed to be an on/off schedule and the heater is available to operate any time the schedule value is greater than 0. The basin heater operates when scheduled on and the outdoor air dry-bulb temperature is below the set point temperature described in the previous field. Regardless of this schedule, the basin heater can only operate when the DX coil is off.
For DX cooling coils located in a unitary system the run settings can be controlled.
Check this option if the coil will operate to meet a sensible load as determined by the inlet node dry-bulb temperature and the dry-bulb temperature setpoint on the control node. When this option is checked the unit will run if there is a sensible load, otherwise if this option is unchecked then the unit will not run if there is only a sensible load.
Check this option if the coil will operate to meet a latent load as determined by the inlet node humidity ratio and the max humidity setpoint on the control node. When this option is checked the coil will operate if there is a latent load. If both sensible and latent loads exist, the system will operate to maintain the temperature set point. When only a latent load exists, the system will operate to meet the humidity ratio set point and requires the use of a heating coil and heating coil outlet air temperature set point manager downstream of this cooling coil to maintain the temperature set point. If this option is not checked then this coil will not run if there is only a latent load.
See Outputs section under Cooling Coil - Single Speed DX coils.