Building Re-Tuning Simulator

Module/Action: Quick Reference
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Overviews
Data Inputs
Outputs
Resources
External Resources
Zone Geometry Overviews
Action: Define Building Shape and Zoning (Zoning Map)

In this step you will create a zoning map of one floor of the building. A key simplifying strategy of the BRS compared to other building modeling tools is to define a representative building geometry and its zones. The assumptions underlying this simplification are as follows:

  1. If the floorplan and the zoning sample are scaled up to the footprint of the entire building, the energy consumption will roughly match that of the full building.
  2. Enough complexity and diversity can be built into the zoning sample to provide a representation of loads and demands to connected HVAC systems for the purpose of simulating complex feedback control to evaluate re-tuning measures.
  3. If the BRS is used to simulate an entire building, use of a floorplan for a single floor as the framework for the zoning map is recommended. If the BRS is used to evaluate a single air handler and the zones it serves, the specific building floor area served by that air handler can be sketched out as faithfully as possible, including sections of multiple floors in the space provided.

If the BRS is used to simulate an entire building, use of a floorplan for a single floor as the framework for the zoning map is recommended. If the BRS is used to evaluate a single air handler and the zones it serves, the specific building floor area served by that air handler can be sketched out as faithfully as possible, including sections of multiple floors in the space provided.

Import Weather and Metered Data Overviews
Action: Import Annual Weather

In this step, you will select the weather station that best represents the general weather conditions at your building. A list of weather stations based on zip code is provided, and the closest weather station is selected by default.

Action: Upload Monthly Billing Data

In this step, the user will locate monthly utility billing data for any applicable meters (electricity, steam, natural gas, chilled water) and upload the monthly data into the BRS. The data is used for the calibration process and for determining the cost impact of applying re-tuning measures.

Action: Upload Interval Metered Data

In this step, the user will locate monthly utility billing data for any applicable meters (electricity, steam, natural gas, chilled water) and upload the monthly data into the BRS. The data is used for the calibration process and for determining the cost impact of applying re-tuning measures.

Building Details Overviews
Action: Enter Building Details

In this step, you will identify high-level details of the building, its location, the type of heating and cooling plant, and its envelope. Many of these details are very difficult to quantify, and wherever possible, defaults and qualitative designations that pertain to quantitative estimates are available.

Action: Define Building Schedules

In this step, you will enter the schedules governing the operation of airside systems. Most of the details for these schedules can be found in the BAS under the scheduling tab or feature.

Equipment Modeling: Heating Plant Overviews
Action: Define Heating Plant

In this section, you will define the heating plant in terms of the details of the heating source and high level details about the hot water loop.

Action: Hot Water Loop Parameters

This section is applicable to heating plants that use either a hot water boiler or district steam with a hot water loop conversion. This section defines the components in the hot water loop and their control.

Equipment Modeling: Cooling Plant Overviews
Action: Chiller Details

In this section, you will define the chillers that provide the cooling source for the chilled water plant.

Action: Chilled Water Loop Parameters

This section is applicable to cooling plants that use either chillers or district cooling with a hot water loop conversion. This section defines the components in the chilled water loop and their control.

Define AHU Overviews
Action: Specify AHU components

In this section, you will specify the layout and control of the air delivery and conditioning system encompassing zone return air, outdoor air intake, conditioning, filtering, humidification and fans. This might encompass one of the following systems or interconnected group of systems:

  • Dedicated outdoor air system only (likely with zone-level conditioning specified later)
  • Single-duct air-handling unit (AHU)
  • Rooftop unit (RTU) or packaged split system
  • Dual-duct AHU
  • Dedicated outdoor air system delivering conditioned outdoor air to the outdoor air intake of single or dual-duct air-handlers…note that the system diagram you create will show only the connection of one outdoor air system to one air-handler, but in reality, there may be a split/header that sends the outdoor air to multiple air-handlers.

This is one of the most challenging modeling steps because it will likely involve intentional modeling decisions to simplify the building airside systems into a representative composite system that approximates the larger whole. In some cases this may not be possible and two instances of the BRS may be required to separately capture different kinds of predominate air-side systems.

It is recommended that the user perform a qualitative evaluation of the airside systems in the building to determine the prevalence of each type of system, and the most common setpoints and control strategies for those common systems. Ultimately, the various airside systems will have to be represented as a single system, using either the most common control strategy and setpoints, or a compromise strategy that approximates the collective operation of the airside systems in the building.

Zone Details Overviews
Action: Specify Zone Equipment and Control

In this section, you will define the HVAC equipment and control at the zone level. This includes any zone conditioning equipment such as VAV Boxes, baseboard heaters, fan-coil/induction units, radiant heating/cooling panels, etc. Many of these components the BRS will model in a similar way. For example, if a zone has a VAV box that provides supply air, it doesn’t matter from an energy perspective whether the heating at the zone level is performed using a reheat coil in the VAV box, a baseboard heater, or a radiant heating panel (assuming in this case, each device is fed from the same hot water loop). Zone-level equipment can be defined separately for perimeter and interior zones. For example, perimeter zones can be defined with both supplemental heating and cooling coils, and interior zones with only supplemental cooling coils.

If the zone has VAV boxes (either single-duct or dual-duct), an airflow response curve needs to be defined. In the case of single-duct boxes, this entails a definition of the airflow response to the thermostat deadband mode, as well as to increases in heating and cooling demands. For dual-duct boxes, this also includes a definition of how the two airflows mix (or flip), and which stream is used for ventilation and in zone deadband.

Finally, this module involves setting the zone thermostat occupied setpoints and unoccupied setback setpoints. These setpoints can be set globally or zone-by-zone.

Simulator Overviews
Action: Run Baseline Simulation
Re-tuning Dashboard Overviews
Action: Re-tuning Dashboard

The Re-tuning Dashboard allows you to apply Re-tuning measure(s) in order to compare the performance of the building with the applied measure(s) to your completed baseline building model. In addition to re-tuning measures, several other common energy upgrade measures are included as options. Measures can be applied individually or in packages.

The measures are organized into different categories in terms of the Re-tuning principle (turn it off, turn it down, mitigate simultaneous heating and cooling, and reduce outdoor air/infiltration) for control measures, or as a capital project or operations and maintenance (O&M) measure. To apply a measure, simply click in the box for that measure that says “Enable Measure”. This will reveal the simulated details about the baseline building for reference on the left side as well as revealing prompts (usually as updates to those baseline details) for simulating the measure on the right side.

When you have applied as many measures as you would like, you can name the new run at the bottom of the page and hit the run button. This will create a new comparison simulation and a new column of results in the table in the Emissions and Savings Impacts module. You can come back to the Re-tuning Dashboard module as often as you need to in order to create new runs and add them to the table in Emissions and Savings Impacts. Below are a list of measures and any unique instructions associated with each:

Trends and Visualization Overviews
Action: Trends and Visualization

This module allows the user to perform an in-depth evaluation of each measure, in order to better understand how the measure impacts the building and to troubleshoot any unexpected results by understanding the underlying behavior of sensors and actuator. This module serves as a virtual building automation system, allowing for the creation of various trend data plots and aggregated profiles of energy consumption, flow rates, temperatures, dampers, valves, etc.

Action: Emissions and Savings Impacts
Calibrate Model Overviews
Action: Calibrate Model

In this module, you have the option to make changes to your baseline model to better calibrate it against metered data from the building. This step is optional and up to the user’s discretion. Some models may be created to represent only a fraction of a full metered facility and calibration may not make sense in those cases. In other cases, taking all reasonable steps to adjust baseline assumptions may not result in a reasonably calibrated model. Calibration is an iterative process, in the sense that the user identifies areas in which there is a discrepancy between modeled energy consumption and metered energy consumption, makes a series of changes expected to move the model toward a more calibrated state, re-runs the model, reviews the results, and repeats the process as necessary until the model is calibrated.

Four metrics are provided to summarize to progress made towards calibration. The first two make use of baseline monthly utility billing data, and the second two make use of baseline interval metered data. Depending on the availability of data, any number of these calibration metrics may or may not be available. The four metrics are as follows:

  1. Overall meter calibration: A metric comparing the total annual energy consumption in each utility from the model to the real building
  2. Seasonal meter calibration: A metric comparing the total energy consumption in three 4-month seasons for each utility from the model to the real building:
    1. Winter (December through March)
    2. Summer (June through September)
    3. Shoulder ( April, May, October, November)
  3. Load profile calibration: A metric comparing the average annual energy consumption hour-by-hour and day-by-day (by utility) between the model and the real building. This metric quantifies how well the daily patterns of consumption in each utility are captured properly by the model.
  4. Temperature bin calibration: A metric comparing the average annual energy consumption by utility, binned by the occupancy status and the associated outdoor air temperature. This metric quantifies how well the model captures the response of each utility to changes in weather, both during occupied and unoccupied hours.
It is possible for most models to achieve over 90% calibration for metric 1 and 2, as the metric is based on a single annual total per utility. For metrics 3 and 4, the calibration process may be much harder and a lower progress indicator of around 70% should be considered sufficient for most models. As the calibration progresses, it may be hard to improve calibration progress in one metric without negatively affecting calibration progress in another metric. The user should decide for themselves when the model feels sufficiently calibrated and move on to evaluation of re-tuning measures.
Zone Geometry Data Inputs
Action: Define Building Shape and Zoning (Zoning Map)
  • Building floor area
  • Building floor plan with north/south orientation (from BAS graphics or architectural drawings)
  • Understanding of space usage patterns
Import Weather and Metered Data Data Inputs
Action: Import Annual Weather
  • Select weather station
Action: Upload Monthly Billing Data
  • Utility billing data in a .csv or .xlsx tabular format with one monthly entry per row, and columns that include the billing start date, billing end date, monthly total, and cost (optional)
Action: Upload Interval Metered Data
  • Interval metered data in a .csv or .xlsx tabular format with one hourly or sub-hourly entry per row, and columns that include the timestamp, meter reading, and outdoor air temperature (optional).
Building Details Data Inputs
Action: Enter Building Details
  • Cooling type
  • AHU type
  • Heating type
  • Wall U-factor
  • Window U-factor
  • Window solar heat gain coefficient (SHGC)
  • Construction thermal mass (qualitative designation)
  • Inter-zone U-factor
  • Infiltration rate
Action: Define Building Schedules
  • AHU schedules
  • Programmed BAS holidays
  • Minimum outdoor air schedule
  • Building exhaust fan schedule
  • Building pressurization fan schedule
  • Occupancy schedule
Equipment Modeling: Heating Plant Data Inputs
Action: Define Heating Plant
  • Number of boilers
  • Boiler type by boiler priority #
  • Boiler sizing by boiler priority #
  • Design boiler efficiency by boiler priority #
  • Part Load Ratios for stage-up
Action: Hot Water Loop Parameters
  • Hot Water Loop Pumping Arrangement (Primary-only or Primary-Secondary)
    • Number of Primary Pumps
    • Number of Secondary Pumps
  • Hot Water Loop Line Loss Coefficient to Unconditioned Space
  • Hot Water- Chilled Water Loop Simultaneous Heating and Cooling
  • Primary pump sizing (hp) by pump
    • [0.1-200 h.p.]
  • Primary Pump Rated Flow (gpm) by pump
    • [40 to 600 x associated boiler size in mmBtu units for pump size in gpm units]
  • Primary Pump Efficiency (qualitative) by pump
  • Primary pump operating head (ft. w.c.)
    • [10 TO 100 ft w.c.]
  • Secondary Pump Sizing (hp) by pump
    • [0.1-200 h.p.]
  • Secondary Pump Rated Flow (gpm) by pump
    • [10-5000 gpm each if no primary pumps specified. Total pump flow rate should range from 0.5x to 2.0x the total primary loop flow rate. Send a warning if these limits are exceeded.]
  • Secondary Pump Efficiency (qualitative) by pump
  • Secondary pump operating head (ft. w.c.)
    • [30 TO 200 ft w.c.]
  • Secondary pump minimum part load ratio
    • [0-1]; 1 for constant speed pumps
Equipment Modeling: Cooling Plant Data Inputs
Action: Chiller Details
  • Number of chillers
  • Chiller capacity by chiller priority #
  • Chiller type by chiller priority #
  • Chiller efficiency by chiller priority #
  • Chiller minimum part load ratio by priority #
  • Part Load Ratios for stage-up
Action: Chilled Water Loop Parameters
  • Chilled Water Loop Pumping Arrangement (Primary-only or Primary-Secondary)
    • Number of Primary Pumps
    • Number of Secondary Pumps
  • Primary pump sizing (hp) by pump
    • [0.1-200 h.p.]
  • Primary Pump Rated Flow (gpm) by pump
    • [10-5000 gpm]
  • Primary Pump Efficiency (qualitative) by pump
  • Primary pump operating head (ft. w.c.)
  • Secondary Pump Sizing (hp) by pump
    • [0.1-200 h.p.]
  • Secondary Pump Rated Flow (gpm) by pump
    • [10-5000 gpm]
  • Secondary Pump Efficiency (qualitative) by pump
  • Secondary pump operating head (ft. w.c.)
  • Secondary pump minimum part load ratio
    • [0-1]; 1 for constant speed pumps
    • [IF cooling type = Chiller AND chiller type = water cooled chiller….]
  • Number of condenser water pumps (if any)
  • Condenser water pump sizing (hp) by pump
  • Condenser water pump flow (gpm) by pump
  • Condenser water pump efficiency (qualitative) by pump
  • Condenser water operating head (ft. w.c.) by pump
  • Condenser water pump staging option (demand-based or one-per-chiller)
  • Number of cooling towers (If any)
  • Cooling tower fan power (hp) by cooling tower
  • Cooling tower capacity by cooling tower
  • Cooling tower staging control
  • Cooling tower type (constant speed, two speed, variable speed)
  • Chilled Water Loop Temperature Control [If cooling type is chillers]
    • Control Type
    • Feedback Variable
    • Reset Parameters
  • Chilled Water Loop Differential Pressure Control [If cooling type is chillers or district cooling]
    • Control Type
    • Reset Parameters
  • Condenser Water Temperature Control [If number of cooling towers is >=1]
    • Control Type
    • Reset Parameters
  • Do secondary pumps run when there is no load? [If cooling type is chillers or district cooling]
Define AHU Data Inputs
Action: Specify AHU components
  • Order of active components in outdoor intake or dedicated outdoor air section (if any)
  • Order of active components in main air handling unit section
  • Order of active components in hot deck section (if any)
  • Control type for each coil (downstream setpoint control or fixed outlet temperature control)
  • Degree of coil leakage
  • Fan temperature rise (per fan; BAS graphics)
  • Fan Efficiency (qualitative)
  • Is the fan motor in the airstream?
  • Observed fan static pressure (BAS graphics)
  • Minimum outdoor air control type
  • Economizer present?
  • Economizer control type
  • High temperature lockout of economizing
  • Low temperature lockout of economizing
  • Filter pressure drop
  • Outdoor Air Humidifier Present?
    • Outdoor Air Humidifier Location
    • Outdoor Air Humidifier Fuel Type
    • Outdoor Air Humidifier RelHum Setpoint
    • Outdoor Air Humidifier Low OAT Lockout
    • Outdoor Air Humidifier High OAT Lockout
  • AHU Section Humidifier Present?
    • AHU Section Humidifier Location
    • AHU Section Humidifier Fuel Type
    • AHU Section Humidifier RelHum Setpoint
    • AHU Section Humidifier Low OAT Lockout
    • AHU Section Humidifier High OAT Lockout
  • Return Fan Present
Zone Details Data Inputs
Action: Specify Zone Equipment and Control
  • Existence of zone-level heating (perimeter and interior)
  • Existence of zone-level cooling (perimeter and interior)
  • Thermostat setpoints (global or by zone)
    • Occupied heating
    • Occupied Cooling
    • Unoccupied Heating
    • Unoccupied Cooling
    • Humidity Setback
  • VAV box sizing factor by zone
  • VAV box airflow control (global or by zone) [if hot deck not defined in ‘Specify AHU Components’]
    • Minimum Heating setpoint
    • Maximum Heating setpoint
    • Minimum Cooling Setpoint
  • Dual Duct airflow control [if hot deck defined in ‘Specify AHU Components’]
    • Maximum Heating Airflow
    • Maximum Cooling Airflow
    • Minimum Airflow
    • Ventilation Source
    • Ventilation in Deadband
    • Control Strategy
Simulator Data Inputs
Action: Run Baseline Simulation
Re-tuning Dashboard Data Inputs
Action: Re-tuning Dashboard
  • No new data inputs are needed, however the user will be required to specify parameters for desired re-tuning measures, typically involving control strategies, feedback variables and ranges of action.
Trends and Visualization Data Inputs
Action: Trends and Visualization
  • No new data inputs are needed
Action: Emissions and Savings Impacts
Calibrate Model Data Inputs
Action: Calibrate Model
  • This step does not require any new data inputs, but instead involves adjusting inputs that may have either been previously defined by the user or are default values that are difficult to quantify during an audit.
Zone Geometry Outputs
Action: Define Building Shape and Zoning (Zoning Map)
  • Building shape defined
  • Number of zones defined (up to nine)
  • Exterior perimeter orientation of zones defined
Import Weather and Metered Data Outputs
Action: Import Annual Weather
  • Hourly weather conditions (temperature, humidity, solar) are imported for the building simulation
Action: Upload Monthly Billing Data
  • Metered utility data uploaded and available for the model calibration process
Action: Upload Interval Metered Data
  • Interval metered data uploaded and available for the model calibration process
Building Details Outputs
Action: Enter Building Details
  • The specification of these building-level details will help the simulation understand the interaction of each zone with other zones and with the environment via the perimeter.
  • The definition of plant-side systems will later determine plant-side HVAC options and energy end use.
Action: Define Building Schedules
  • This step will define the availability schedules by which airside HVAC systems are permitted to run.
  • AHUs are still able to operate for night cycle operation when zones fall outside of their night setback thermostat bounds.
Equipment Modeling: Heating Plant Outputs
Action: Define Heating Plant
  • The boilers, their capacity, efficiency profiles, and staging scheme will be defined
Action: Hot Water Loop Parameters
  • The hot water pumping configuration, components and baseline control will be defined
Equipment Modeling: Cooling Plant Outputs
Action: Chiller Details
  • The chillers will be defined and ready to stage up and down appropriately and link up to a chilled water loop.
Action: Chilled Water Loop Parameters
  • The Chilled water pumping configuration, pumps, cooling towers and baseline control of these systems will be defined
Define AHU Outputs
Action: Specify AHU components
  • The configuration of a typical air-conditioning system (AHU, rooftop unit, dedicated outdoor air system, or combination thereof), will be defined in terms of
    • Available components (fans, heating coils, cooling coils, mixing box, humidifiers)
    • Sequence of components
    • Baseline control of components
Zone Details Outputs
Action: Specify Zone Equipment and Control
  • This step will define the baseline control of zone thermostats, air delivery systems (e.g. VAV boxes and air terminals), and supplemental zone-level heating and cooling systems affecting the zones created earlier.
Simulator Outputs
Action: Run Baseline Simulation
Re-tuning Dashboard Outputs
Action: Re-tuning Dashboard
  • The user will apply all investigations of interest, including re-tuning measures, packages of measures, and parametric studies of changes to the HVAC system and its controls.
Trends and Visualization Outputs
Action: Trends and Visualization
  • This step exists for the user to visualize the impact from re-tuning, and does not have a specific output.
Action: Emissions and Savings Impacts
Calibrate Model Outputs
Action: Calibrate Model
  • After this step, the baseline model will be completed, considered sufficiently representative of the actual building and ready for evaluation of re-tuning measures.
Zone Geometry BRS Resources
Action: Define Building Shape and Zoning (Zoning Map)
  • no action specific resources
Import Weather and Metered Data BRS Resources
Action: Import Annual Weather
  • no action specific resources
Action: Upload Monthly Billing Data
  • no action specific resources
Action: Upload Interval Metered Data
  • no action specific resources
Building Details BRS Resources
Action: Enter Building Details
  • no action specific resources
Action: Define Building Schedules
  • no action specific resources
Equipment Modeling: Heating Plant BRS Resources
Action: Define Heating Plant
  • no action specific resources
Action: Hot Water Loop Parameters
  • no action specific resources
Equipment Modeling: Cooling Plant BRS Resources
Action: Chiller Details
  • no action specific resources
Action: Chilled Water Loop Parameters
  • no action specific resources
Define AHU BRS Resources
Action: Specify AHU components
  • no action specific resources
Zone Details BRS Resources
Action: Specify Zone Equipment and Control
  • no action specific resources
Simulator BRS Resources
Action: Run Baseline Simulation
  • no action specific resources
Re-tuning Dashboard BRS Resources
Action: Re-tuning Dashboard
  • no action specific resources
Trends and Visualization BRS Resources
Action: Trends and Visualization
  • no action specific resources
Action: Emissions and Savings Impacts
  • no action specific resources
Calibrate Model BRS Resources
Action: Calibrate Model
  • no action specific resources
Zone Geometry External Resources
Action: Define Building Shape and Zoning (Zoning Map)
  • no action specific external resources
Import Weather and Metered Data External Resources
Action: Import Annual Weather
Action: Upload Monthly Billing Data
  • no action specific external resources
Action: Upload Interval Metered Data
  • no action specific external resources
Building Details External Resources
Action: Enter Building Details
  • no action specific external resources
Action: Define Building Schedules
  • no action specific external resources
Equipment Modeling: Heating Plant External Resources
Action: Define Heating Plant
  • no action specific external resources
Action: Hot Water Loop Parameters
  • no action specific external resources
Equipment Modeling: Cooling Plant External Resources
Action: Chiller Details
  • no action specific external resources
Action: Chilled Water Loop Parameters
  • no action specific external resources
Define AHU External Resources
Action: Specify AHU components
  • no action specific external resources
Zone Details External Resources
Action: Specify Zone Equipment and Control
  • no action specific external resources
Simulator External Resources
Action: Run Baseline Simulation
  • no action specific external resources
Re-tuning Dashboard External Resources
Action: Re-tuning Dashboard
  • no action specific external resources
Trends and Visualization External Resources
Action: Trends and Visualization
  • no action specific external resources
Action: Emissions and Savings Impacts
Calibrate Model External Resources
Action: Calibrate Model
  • no action specific external resources