Data on this tab is used for controlling the zone internal conditions during the simulation and also for autosizing heating, cooling and outside air equipment related to the zone.
This is the name of the building zone with which the current HVAC zone is linked.
If the 2-Detailed HVAC Detailed HVAC Activity data model option is set then you can select schedules defining zone heating and cooling setpoint temperatures on this dialog. Otherwise, if the 1-Simple HVAC option is selected then zone setpoint temperatures and schedules are defined on the Activity and HVAC model data tabs respectively and the Thermostat schedule data is not displayed on this dialog.
Note: The temperatures defined in these schedules must be in °C regardless of whether you are using IP or SI units in the interface.
This is the zone heating temperature schedule. Values in the schedule are temperatures (in °C).
This is the zone cooling temperature schedule. Values in the schedule are temperatures (in °C).
If the 2-Detailed HVAC Detailed HVAC Activity data model option is set then you can select schedules which define zone heating and cooling setpoint PMV values on this dialog. Otherwise, if the 1-Simple HVAC option is selected then zone setpoint PMV values and schedules are defined on the Activity and HVAC model data tabs respectively and the Thermostat schedule data is not displayed on this dialog.
The Thermal comfort calculator tool can be used to derive PMV values based on perhaps more familiar parameters.
This is the zone heating PMV schedule. Values in the schedule are PMV indices, typically in the range -3 to 3.
This is the zone cooling PMV schedule. Values in the schedule are PMV indices, typically in the range -3 to 3.
This check-box is used to specify whether or not the zone has humidity control.
If the 1-Simple HVAC option is selected then zone RH setpoints on the Activity tab are used and the demand schedule data on this dialog defines the times when these setpoints operate.
Humidifying demand schedule
This is a schedule that defines the times when humidification may be required. The schedule should have only values of 0 (for times when no humidification is required) or 1 (when humidification to the humidification setpoint defined on the Activity tab is required).
Dehumidifying demand schedule
This is a schedule that defines the times when dehumidification may be required. The schedule should have only values of 0 (for times when no dehumidification is required) or 1 (when dehumidification to the dehumidification setpoint defined on the Activity tab is required).
If the 2-Detailed HVAC Detailed HVAC Activity data model option is set then you can select schedules defining zone relative humidity setpoints on this dialog.
Humidifying RH setpoint schedule
This is a schedule that defines the humidifying relative humidity setpoint, expressed as a percentage (0-100), for each timestep of the simulation.
Dehumidifying RH setpoint schedule
This is a schedule that defines the dehumidifying relative humidity setpoint, expressed as a percentage (0-100), for each timestep of the simulation.
More information on controlling humidity is available in the Humidity control section.
The rest of the General tab of the HVAC Zone dialog is related to Detailed HVAC autosizing calculations only.
This is the supply air temperature (in °C or °F) for the zone cooling air flow rate calculation. Air is supplied to the zone at this temperature during the cooling design day simulation; the zone load is met by varying the zone air flow rate. The maximum zone flow rate is used as the zone cooling design air flow rate.
This is the humidity ratio in kilograms of water per kilogram of dry air of the supply air in the zone cooling autosizing air flow rate calculation.
This is the minimum zone design cooling volumetric flow rate expressed as a fraction of the zone design cooling volumetric flow rate for VAV systems only. In all cases the maximum flow derived from Cooling minimum flow per zone floor area, Cooling minimum air flow, and Cooling minimum air flow fraction is used to set a minimum supply air flow rate for the zone for VAV systems. The default is zero. This input is currently used in sizing the fan minimum flow rate. It does not affect other component auto-sizing.
Note: This value is only used when the zone is connected to a VAV Air loop, in which case this data is used for sizing and not for the simulation itself.
This is the zone level cooling sizing ratio. The zone design cooling air flow rates and loads will be multiplied by the number input in this field. The default value comes from the Zone group dialog whose default Zone cooling sizing factor is the ASHRAE recommended cooling oversizing factor of 1.15.
This is the design zone cooling air flow rate (in m3/s or ft3/min). This setting is only required if Cooling design air flow method is specified as 2‑Flow/zone. This value will be multiplied by the global or zone sizing factor and by zone multipliers.
This is the minimum zone cooling volumetric flow rate per square meter (units are m3/s-m2). This setting is only required if the Cooling design air flow method is specified as 3‑Design day with limit. In this case it sets a lower bound on the zone design cooling air flow rate. In all cases the maximum flow derived from Cooling minimum flow per zone floor area, Cooling minimum air flow, and Cooling minimum air flow fraction is used to set a minimum supply air flow rate for the zone for VAV systems. The default is 0.000762 m3/s-m2, corresponding to 0.15 cfm/ft2. The applicable sizing factor is not applied to this value.
This is the minimum zone cooling volumetric flow rate (in m3/s). This field is used when Cooling design air flow method is specified as 3‑Design day with limit. In this case it sets a lower bound on the zone design cooling air flow rate. In all cases the maximum flow derived from Cooling minimum flow per zone floor area, Cooling minimum air flow, and Cooling minimum air flow fraction is used to set a minimum supply air flow rate for the zone for VAV systems. The default is zero. The applicable sizing factor is not applied to this value.
This is the supply air temperature (in °C or °F) for the zone heating design air flow rate calculation. Air is supplied to the zone at this temperature during the heating design day simulation, The zone load is met by varying the zone air flow rate. The maximum zone flow rate is used as the zone heating design air flow rate.
This is the humidity ratio in kilograms of water per kilogram of dry air of the supply air in the zone heating design air flow rate calculation.
This is the zone level heating sizing ratio. The zone design heating air flow rates and loads will be multiplied by the number input in this field. The default value comes from the Zone group dialog whose default Zone heating sizing factor is the ASHRAE recommended heating oversizing factor of 1.25.
There are three options;
This is the design zone heating air flow rate (in m3/s or ft3/min). This setting is only required if Heating design air flow method is specified as 2‑Flow/zone. This value will be multiplied by the global or zone sizing factor and by zone multipliers.
This is the maximum zone heating volumetric flow rate per square metre (units are m3/s-m2). This setting is only required if the Heating design air flow method is specified as 3‑DesignDayWithLimit. In this case it sets an upper bound on the zone design heating air flow rate. In all cases the maximum flow derived from Heating maximum flow per zone floor area, Heating maximum air flow, and Heating maximum air flow fraction is used to set a maximum heating supply air flow rate for the zone for VAV systems. The default is 0.002032 m3/s-m2, corresponding to .40 cfm/ft2. This input is not currently used for auto-sizing any of the components.
This is the maximum zone heating volumetric flow rate in m3/s. This setting is only required if the Heating design air flow method is specified as 3‑Design day with limit. In this case it sets an upper bound on the zone design heating air flow rate. In all cases the maximum flow derived from Heating maximum flow per zone floor area, Heating maximum air flow, and Heating maximum air flow fraction is used to set a maximum heating supply air flow rate for the zone for VAV systems. The default is 0.14158 m3/s, corresponding to 300 cfm. This input is not currently used for auto-sizing any of the components.
When the Detailed HVAC Activity data is set to 1-Simple HVAC then all data under the Outdoor Air Sizing header is disabled and the outdoor air requirement settings are copied from the corresponding building zones' Activity and/or HVAC model data as described below.
When the Detailed HVAC Activity data is set to 2-Detailed HVAC then the outdoor air requirement is defined here on the HVAC zone dialog.
There are five options:
Note: If the Detailed HVAC Activity data is set to 1-Simple HVAC then this option is disabled and the Outdoor air method is copied from the corresponding building zones' HVAC model data.
This is the design outdoor air flow rate per person for this zone (in m3/s or ft3/min). This setting is only required if either one of the 2‑Flow/person, 4‑Sum, or 5‑Maximum options have been selected for the Outdoor air method. The default is 0.00944 m3/s (20 cfm per person). An outdoor air flow rate is calculated based on the total number of people assigned to the zone. Occupancy schedule values are not applied.
Note: If the Detailed HVAC Activity data is set to 1-Simple HVAC then this option is disabled and the Outdoor air flow per person is copied from Outdoor air flow per person from the corresponding building zones' Activity model data.
This is the design outside air volumetric flow rate per square meter of floor area (in m3/s-m2). This setting is only required if either one of the 3‑Flow/area, 4‑Sum, or 5‑Maximum options have been selected for the Outdoor air method. This value is multiplied by the zone floor area to obtain a flow rate.
Note: If the Detailed HVAC Activity data is set to 1-Simple HVAC then this option is disabled and the Outdoor air flow per zone floor area data is copied from the corresponding building zones' Activity model data.
This is the design outdoor air flow rate for this zone (in m3/s or ft3/min). This setting is only used if either one of the 1‑Flow/zone, 4‑Sum, or 5‑Maximum options have been selected for the Outdoor air method.
Note: If the Detailed HVAC Activity data is set to 1-Simple HVAC then this option is disabled and the flow per zone is calculated from the ac/h value set on the HVAC model data tab and displayed here.