Building Re-Tuning Simulator

Simulation Modules
Zone Geometry
Define Building Shape and Zoning
Metered Data and Costs
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Electricity Tariff
Upload Interval Metered Data
Building Details
Enter Building Details
Equipment Modeling: Heat Pump Plant
Heat Pump Plant
Equipment Modeling: Heating Plant
Define Heating Plant
Hot Water Loop Parameters
Equipment Modeling: Cooling Plant
Chiller Details
Chilled Water Loop Parameters
Define AHU
Specify AHU components
Zone Details
Specify Zone Equipment and Control
Building Schedules
Enter Building Schedules
Simulator
Run Baseline Simulation
Calibrate Model
Calibrate Model
Re-tune Building
Re-tuning Dashboard
Economic Assumptions
Re-tuning Simulator
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Trends and Visualization
Emissions and Savings Impacts
Hot Water Loop Parameters
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Resources

Inputs Needed

  • 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

Outputs

  • The hot water pumping configuration, components and baseline control will be defined

Overview

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.

In-Depth

For buildings with steam heating coils, the components in this section can be left blank to indicate that there is no hot water loop to model. A set of hot water primary pumps can be modeled. Note that this set of pumps should only be modeled if there is a separate building hot water loop. If there is a single set of pumps that flows hot water through the boilers (or heat exchanger) AND out to the building heating coils, only the “building/secondary” pumps should be defined, and the primary pumps left blank.

A set of hot water primary pumps can be modeled. Note that this set of pumps should only be modeled if there is a separate building hot water loop. If there is a single set of pumps that flows hot water through the boilers (or heat exchanger) AND out to the building heating coils, only the “building/secondary” pumps should be defined, and the primary pumps left blank. The number of available primary pumps can be set to either 0 or to the number of boilers previously defined.

For hot water pumps, the constant speed pumps (primary loop for the boilers) take as inputs the pump design sizing (nameplate horsepower), rated flow rate, pump efficiency and operating head. All of these inputs are optional for the user in the sense that they can either be auto-sized using rule-of-thumb defaults according to the boiler size, or have typical defaults available. Building/secondary pumps are handled the same way in the model, with the exception that they are assumed to be variable speed and have an additional input of minimum part load ratio (with default of 25% available). A constant speed pump can be modeled by entering 100% for this field.

There are four types of control that need to be specified for the hot water loop:

  • Heating Coil Lockout: Some buildings use an outdoor air temperature-based lockout on the heating plant/heating coils. If so, this lockout can be set here.
  • Hot water temperature control: The setpoint control for the outlet water temperature must be specified. The setpoint can be set as constant or a linear reset can be specified to control the hot water temperature setpoint based on either outdoor temperature or average hot water valve command
  • Hot water differential pressure control: The setpoint for the hot water loop differential pressure can be set to a constant value, or can use a linear reset based on average or maximum hot water valve command, average or maximum zone heating demand, or outdoor air temperature.
  • Building/secondary hot water pump on/off control: Some building hot water pumping systems may shut down completely when there is no demand for hot water at the building level, whereas others may stay on at all times, and others may stay on any time the outdoor air temperature is below a threshold temperature. If the control is unknown, it is recommended to have the pumps shut off when there is no demand.