2 System Parameters Interface – Overview and Main Elements
Managed systems
The System Parameters dialog works with ‘managed systems’. A managed system has a system frame and a multiplexed set of zones and related components and controllers.
Each managed system in the ApacheHVAC file has a System Parameters dialog that provides a user-friendly means of editing and in many cases deriving its component level parameters; with user inputs alongside zone loads, sizing parameters, derived values, and engineering checks.
While the entire system must be contained within the system frame, it can be connected via airflow paths to other systems, which may or may not also be managed systems. However, only the components and controllers within the system frame can be linked to the System Parameters dialog.
The System Parameters dialog is accessed either by double-clicking top bar of the system frame or by clicking the System Parameters toolbar button shown above, and then selecting the ‘System to edit’.
System frame
The system frame is a container, a clickable element, and a means for providing feedback. The system frame changes color, has symbols added or removed at the right end of the top bar, and provides ToolTip information to indicate the current status of the system with regard to user edits, autosizing, and error conditions.
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Summary of System Frame Status and ToolTips
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User action or trigger
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Frame, top bar, and text color
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ToolTip
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System unchanged from HVAC library; no user edits or autosizing.
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“HVAC network unaltered since being loaded from system or user HVAC systems library—no user edits or auto-sizing yet”
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User edits have been made and saved, but not yet assigned.
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“User edits have been saved, but not assigned to the components and controllers in the HVAC network.”
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User edits completed and assigned to components and controllers.
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“User edits have been saved and assigned to the components and controllers in the HVAC network. If previously auto-sized, at least one or more auto-sized value has been overridden by a saved user edit. Unaltered auto-sized values remain in green text.”
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Error condition in System Parameters; must be corrected before assigning.
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“There is an error in a user-edited value or derived parameter. This error is highlighted in the dialog and must be cleared prior to the Assign operation or any simulation of the HVAC system”.
List of the parameters in error is provided following this text.
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Zone-level sizing has been completed and assigned/updated (auto or manual).
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“Zone-level auto-sizing has been completed and sized values have been assigned to components and controllers in the HVAC network.”
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Zone-level sizing or Zone- and then System-level sizing has been completed but not assigned/updated either automatically or manually.
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“Zone-level autosizing or zone- and then system-level autosizing have been completed, but sized values have not been assigned either automatically (via the ASHRAE Loads interface) or manually.”
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Zone-level sizing has been completed & assigned, but subsequent edits have not been applied to the components and/or controllers.
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“Zone-level sizing completed, but revised data associated with subsequent user edits has not been assigned. System-level sizing, if previously completed, will need to be re-run to account for changes.”
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System-level sizing completed, but zone-level sizing for this system has not been completed (e.g., if intentionally set up and sized manually at zone level, then auto-sized only at system level for coils, fans, and plant equipment/loops).
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“System-level autosizing have been completed and applied, but zone level autosizing has not.”
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Autosizing at zone and system level have been completed and values assigned to components and controllers.
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“Both zone- and system-level auto-sizing have been completed and sized values assigned to components and controllers in the HVAC network.”
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System Parameters dialogs
The System Parameters dialog displays data applying to both system level and zone level.
A few basis system-level parameters, including the system name, option to autosize the system, fundamental type of configuration, variable-air-volume (VAV) vs. constant-air-volume (CAV), edit mode, current layer, access to the Edit Multiplex dialog, and a toggle for IP vs SI units are provided at the top of the dialog so as to remain visible and accessible whenever the dialog is open.
The tabbed middle section provides access to most user inputs, options, and autosized or derived values. The remainder of this user guide is dedicated mainly to describing each of these in detail.
Text color is used to indicate values that are from Space Data (magenta), will be directly autosized (light blue), have been autosized (green), edited and differ from the same parameter on other layers (orange), or are in error and must be addressed (red). These colors can be customized via the ApacheHVAC Preferences dialog.
Conditional formatting is used to highlight certain fields containing values that will significantly influence the system minimum outside air or that may bring into question the system capability to provide this at all times.
The bottom section provides access to the Zones Tabular Edit dialog described below (also accessible via the toolbar), along with copy & paste functions to copy all data for a tab from one layer to another, two save options for saving edits without applying them, and ‘Assign’, which applies values to the components and controls on the associated system network.
Tabbed sections for System Parameters and Zones Tabular Edit dialogs
Zones Tabular Edit is a customizable spreadsheet-like dialog for viewing and editing all parameters from the System Parameters dialog (excepting only systems Schedules) for all zones on the system in a single view. This is also the means by which data can be exported for documentation or manipulation in spreadsheets, etc., and can be imported specifically with respect to editable columns of data.
Fields or ‘cells’ for select zone-level parameters use conditional formatting color scheme to draw attention to the zones that are driving system minimum ventilation rates or to draw attention to a value that may be of concern, but which is not strictly speaking in error.
Both the System Parameters dialog and its counterpart, the Zones Tabular Edit dialog, are organized with tabs for system- and zone-level parameters. These are more or less the same tabs and provide access to all of the same parameters; however, the Zones Tabular Edit dialog excludes the system-level ‘Schedules’ tab, subdivides some of the tabs to make the number of default columns more manageable, and places ‘Loads Data’ first.
System Parameters dialog tabs (fixed):
· Schedules
· System Parameters
· Zone Temp, Humidity & Equipment
· Zone Ventilation & Exhaust
· Zone Loads & Supply Airflows
· Zone Airflows, Turndown & Engineering Checks
Zones Tabular Edit dialog tabs (customizable):
· Loads Data
· System Parameters
· Zone Temp, Humidity & Equipment
· OA Ventilation
· Air Changes & Exhaust
· Cooling Airflows
· Heating Airflows
· Zone Design Airflows
· Engineering Checks
ApacheHVAC Toolbar buttons
Toolbar buttons for ‘System Parameters’, ‘Zones Tabular Edit’, and ‘Global System Parameters Assignment’ are the 2nd, 3rd, and 4th buttons on the system sizing section of the ApacheHVAC toolbar shown below:
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The first two simply open the System Parameters and Zones Tabular Edit dialogs, as described elsewhere. The ‘Global System Parameters Assignment’ simultaneously assigns values from system parameters dialogs for all HVAC networks in the currently open ApacheHVAC file to the components and controllers in those networks.
