Meters
Meters
This section allows you to create custom meters and assign end uses to custom meters, as well as an opportunity to configure and enable demand limiting controls for electricity meters. The use of custom meters is to allow for the measurement of consumption for specific end uses in the building. There are many standard outputs that provide for categorization of end uses; custom meters enable you to measure specific end uses over the simulation period. The consumption and demand costs reported in the output reports are for the entire building, even if there are sub-meters in place.
When entering the Meters subsection, you will be prompted, “Custom Meters are not required to perform economic analysis. Would you like to create custom meters now or skip to the next section?”
If you have no need to sub-meter end uses in the project, select “Next Section” and the Life Cycle Parameters subsection will be entered. By default, all end uses are assigned to the default building meter for the corresponding fuel type. To create custom meters, select “Create Meters” and access will be granted to the Meters subsection. If there are no custom meters created within your project, this prompt will be displayed whenever the Meters subsection is entered.
Meters Tab
To view the end uses assigned to a meter, click the Meters tab in the tree view. By default, TRACE® 3D PLUS automatically creates a fuel meter for each fuel type that exists in the project alternative. By selecting a meter on the left tree, all end uses currently assigned to that meter are shown in the workspace. Once a custom meter has been created, end uses may be reassigned for sub-metering purposes.
To setup demand limiting, click the Demand Limit tab in the tree view.
Tree Structure
The tree structure displays the fuel types along with the utility rates and the meter(s) assigned to them. To modify the assignment of end uses to a meter, first click on the meter name on the tree. Then, click the meter manager button at the bottom of the tree. The assignment pane will be displayed, end uses are added to the meter by clicking the “+” symbol for the end use. The end uses assigned to the meter are not reflected in the tree. They will be displayed in the workspace as added to a particular meter.
Add New Meter bar
The meters section allows you to create custom (sub)-meters in the project (e.g. Lighting Electric Meter), which can then be assigned to a different utility rate or used only to sub-meter part of a building’s consumption.
The “Add Meter” bar at the top of the screen allows the creation of custom sub-meters for any utility type consumed in the building model. The only buttons that will be available correspond to the utilities consumed by the end uses within the project alternative. Custom meters cannot be created for District Heating or Cooling, including steam.
For example, if a project alternative consumes only electricity and natural gas, only the Electricity and Natural Gas add meter buttons are displayed in the bar. If there are more buttons than can fit on the screen, you may need to scroll to the right to see all the Add Meter Buttons. When a new meter is created that includes steam, the default name is “FuelType”, where “FuelType” is Electricity, Natural Gas, etc. Any subsequent meter is appended with “00n” where n is the number of custom meters than have been added to the project.
Disable Custom Meter Checkbox
When the Disable Custom Meter checkbox is unchecked, meters may be assigned to utility rates, enabling demand limiting to be configured. It also determines whether the output reports will contain information about custom meters. You may configure custom meters, but leave them as disabled if you don’t need to see the data. The configuration is preserved so you don’t have to recreate the meters, even if you don’t wish to see the data.
Workspace
The workspace in the meters section displays the end uses attached to individual meters. By default, all the end uses are assigned to the default building meters. For example, all the electricity loads (end uses) are assigned to the building electricity meter. When adding a new meter, no end uses will be assigned to it initially, but can be added on this screen.
Assigned to Utility Rate
This combo box allows you to assign meters to a utility rate from the Meters subsection without returning to the Utilities subsection. This is convenient when custom meters have been created to avoid going back to the Utilities subsection for meter assignment. The combo box displays only utility rates that contain rate tariffs for fuel meters by the selected meter. The combo box is not displayed when the selected meter is a custom meter and the Disable Custom Meter checkbox is checked. In other words, you may not assign a disabled meter to a utility rate.
Meter Manager
To assign end uses to a meter, click the Meter Manager Button in the Meters Tree. A pane will appear to the right of the tree containing all end uses in the project alternative. They are sorted into three tabs: Internal and Miscellaneous, System Equipment and Plant Equipment. To add an end use to a meter, select the meter in the tree on the right and click the plus (+) sign corresponding to the load to be assigned. The tree view is not updated with end uses as they are assigned – you can close the Meter Manager to view assigned end uses in the read-only workspace.
End uses within each category tab are sorted by the meter to which they are currently assigned. No end use can be unassigned without being reassigned to another meter, i.e.) there cannot be an end use that is not being metered. If a meter is deleted, and it previously had end uses assigned to it, those end uses will be reassigned to the default building meter. There is a tree structure followed within the Meter Manager. For example, all electric end uses within a room may be added to a meter by simply clicking on the "+" for the room. This applies to system and plant equipment as well.
If all end uses have been assigned to custom meters, then the default building meter may be deleted. At that point, if you delete a custom meter, the building meter is re-created and those end uses that were on the deleted custom meter are reassigned to the default building meter. In this case, the costs reported in the Economics Summary will still be reported based on the total building consumption and demand.
Internal and Miscellaneous
The end uses that are not part of the project alternative’s HVAC system. They include interior and exterior lighting, base utilities, and plug loads.
System Equipment
The end uses that are part of the airside system, including fans, coils, energy recovery devices, and controls.
Plant Equipment
The end uses that are part of the equipment used to generate heating or cooling within the project alternative. These include compressors and heat rejection equipment as well as hot or chilled water pumps and ancillary equipment and controls used for the plant equipment.
Search for End Use
There may be many end uses within your project alternative. You can search by the name of the end use that is to be assigned to the selected meter. The search results will include any end use from the category being searched with the searched out value somewhere in the name.
Demand Limit Tab
Demand limiting, or demand management, is a strategy for reducing a building’s demand for electricity only. Utility companies typically charge a monthly fee for “demand charges” that is based on the peak demand during a certain time period. Often the peak demand charge is set by one exceptional day that is much higher than the peak demand for an average day during the month. Therefore, to save utility costs, it is in the interest of building owners to find ways to manage the demand on peak days.*
The only loads that can be demand limited are lighting, exterior lighting and internal load electric equipment. Only end uses assigned to the meter will be available for demand limiting. As such, if the building meter is to be used to determine when to limit demand, then it must contain all end uses that are to be limited.
However, even if the building contains custom meters and end uses have been assigned, it’s implied that the demand limiting decision will be based on the demand of the entire building, not the delta between the building meter and the custom meters within the project. When demand limiting is based on a custom meter, that meter’s demand will be used to determine the point at which demand limiting occurs.
Demand limiting may not be configured for a meter that is not assigned to a rate tariff.
Tree Structure
The meters in the project are displayed in a tree, similar to the Meters Tab, however, only electricity meters can be demand limited, thus they are the only meter type shown in this tree. They are displayed based on the type of demand limiting that has been configured. The default priority is “ALL”, thus initially all electricity meters will be categorized under “Priority – ALL”.
Only meters may be selected from the tree.
Workspace
With a meter selected in the Demand Limit Tree, the workspace displays the end-uses assigned to the meter along with the demand limit target, schedule and priority.
Demand Limiting Checkbox
If this box is checked, demand limiting is enabled for the selected meter using the settings from the workspace area.
Target Demand Limit
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Default: 100
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Min & Max: 0 to 100,000,000
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Typical Range: 0 to 1,000
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Units: kW
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If demand limiting controls are to be used, enter the maximum total kW at which the demand limited end uses on that meter are allowed to operate.
Target Demand Schedule
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Default: Available 100%
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Min & Max: 20 to 100
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Typical Range: 0 to 100
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Units: %
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Select the schedule for specifying the utilization target demand limits. This schedule is a multiplier on the target demand limit. If different levels of demand management are required during various time periods throughout the day, they can be managed using this schedule. Typically the default schedule will be used.
Do not set this schedule to 0% during hours that demand limiting is not enabled, this will limit all demand for assigned end uses on the selected meter, as it signifies 0% of the Target Demand Limit. These schedules come from the Multipliers folder within the Schedules Library. Demand management is only applicable during peak periods, so if a tariff has no Time of Use periods, demand limiting is allowed during all hours of the day at the resultant value produced by the Target Demand Limit and the Target Demand Schedule and Availability combination.
Target Demand Availability
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Default: Available all year
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Min & Max: N/A
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Typical Range: N/A
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Units: N/A
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Select the schedule that determines the time periods that demand limiting will take place. This is a binary schedule, hours with a value of ‘1’ mean that demand limiting is enabled. In hours where the value is zero mean that there will be no demand limiting of end uses based on the metered demand.
These schedules come from the Availability Managers folder within the Schedules Library.
Demand Priority
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Default: All
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Min & Max: N/A
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Typical Range: N/A
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Units: N/A
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This field indicates what logic should be used to activate demand limiting on end uses configured as Demand Limiting Loads.
“All” activates demand limiting for all end uses to achieve the maximum demand reduction. “Sequential” treats the list of end uses as a sequential priority list, i.e., the first end use in the list is activated first, then the second, etc., until the demand falls below the limit.
Demand Limiting Loads
When the priority is “All”, the order in which the loads are added to demand limiting does not matter. However, when the demand priority is “Sequential”, the list order matters, so the loads are numbered (1,2,3,etc.). The loads should be ordered in the list, with those higher in the list being the first to be turned off.
As an example, when “All” is used, and the demand limit has been reached, all loads in that demand manager are limited. When “Sequential” is used, the loads are shut down in sequential order until the demand limit is no longer exceeded. The arrows are used to increase an end use’s demand limiting priority. Typically, nonessential end uses would be limited first, thus residing nearest the top of the list. An end use is moved to the right hand side of the workspace using the “-” symbols, denoting the end use will not be limited based on demand.
The search bar at the top of this section may be used to find an end use, when all or part of the name is known.
Available Loads for Demand Limiting
The available loads for demand limiting include electric exterior lights, electric interior lights, and electric internal load equipment. An end use is moved to the left hand side of the workspace using the “+” symbols. Only end uses assigned to the selected meter are displayed in this area. The search bar at the top of this section may be used to find an end use, when all or part of the name is known.
Consider the following example: A meter is required to reduce demand on hallway lights when the building meter exceeds 500kW between 8AM and noon, and to 400kW between the hours of noon and 5PM by turning them off sequentially, until the target is met. The selected meter in the tree is Building Electricity. Each of the hallway lights to be limited must be moved to the Demand Limiting Loads section on the left hand side of the workspace, and ordered as necessary.
The Target Demand Limit is set to 500 kW. The Target Demand Availability schedule should be configured such that from 8AM to 5PM the value is ’1’, for all other hours the value is zero. The Target Demand schedule should reflect that the value is 100 from hours 8AM to noon and 80 from the hours of noon to 5PM to reflect the 500kW and 400kW target limits.