Buildings.Fluid.Storage.Ice.Validation.ExperimentNIST

Validation from experimental data

Information

This package contains calibration examples using experimental data from the Intelligent Building Agents Laboraotry at the National Institute of Standards and Technology (NIST). The ice storage tank at NIST contains 3,105 L of water and when fully frozen the ice has a capacity of 274 kWh, designed to be discharged over an eight-hour period with an inlet temperature of 10 °C. The chilled water that flows through the ice tank is a 30 % PG and 70 % water solution, and the heat exchanger inside the ice tank is a spiral wound polyethylene tube. The chiller used for charging has a nominal capacity of 36.1 kW. However, due to the off-design conditions and wornout, the ice tank has a capacity of abour 264 kWh.

The experimental data are located at "IceStorage/Resources/data/Experiment". The data are prepared into 5 columns, and the description of each column is explained below.

• 1st column: time step in seconds
• 2nd column: measured ice tank inlet temperature in Celsius
• 3rd column: measured ice tank outlet temperature in Celsius
• 4th column: measured ice tank fluid mass flow rate in kg/s
• 5th column: measured dimensionless ice tank state-of-charge

The data are generated with bypass valve fully closed, and collected an interval of 10 seconds.

Calibration

The performance curves were calibrated using curve-fitting techniques based on the measurement. For dishcarging scenario, three experiments were conducted and used for calibration. The discharging capacity of the ice tank depends on the current state-of-charge, the inlet and outlet temperature of the ice tank. For charging scenario, one set of experiment data was used in this package. When under charging, the chiller operated at a constant cooling rate, and therefore the ice tank charging rate was almost constant. An average of the measured charging rate, 167.79 kW, during the experiment was used for the calibration.

Reference

Li, Guowen, et al. "An Ice Storage Tank Modelica Model: Implementation and Validation." Modelica Conferences. 2021.

Extends from Modelica.Icons.ExamplesPackage (Icon for packages containing runnable examples).

Package Content

Name	Description
Charging	Validation against charging experiment
Discharging1	Validation against discharging experiment 1
Discharging2	Validation against discharging experiment 2
Discharging3	Validation against discharging experiment 3
BaseClasses	Base classes for validation package

Buildings.Fluid.Storage.Ice.Validation.ExperimentNIST.Charging

Validation against charging experiment

Information

This example is to validate the developed ice tank model for charging mode.

Extends from Buildings.Fluid.Storage.Ice.Validation.ExperimentNIST.BaseClasses.PartialChargingDischarging (Base example).

Parameters

Modelica definition

Buildings.Fluid.Storage.Ice.Validation.ExperimentNIST.Discharging1

Validation against discharging experiment 1

Information

This example is to validate the developed ice tank model for discharging mode using data generated from experiment 1. The outlet temperature setpoint is set to 2 degree below the measured temperature because the measurement data was taken when the bypass was fully closed. In this way, the implemented model will automatically close the bypass valve during charging.

Extends from Buildings.Fluid.Storage.Ice.Validation.ExperimentNIST.BaseClasses.PartialChargingDischarging (Base example).

Parameters

Modelica definition

Buildings.Fluid.Storage.Ice.Validation.ExperimentNIST.Discharging2

Validation against discharging experiment 2

Information

This example is to validate the developed ice tank model for discharging mode using data generated from experiment 2. The outlet temperature setpoint is set to 2 degree below the measured temperature because the measurement data was taken when the bypass was fully closed. In this way, the implemented model will automatically close the bypass valve during charging.

Extends from Buildings.Fluid.Storage.Ice.Validation.ExperimentNIST.BaseClasses.PartialChargingDischarging (Base example).

Parameters

Modelica definition

Buildings.Fluid.Storage.Ice.Validation.ExperimentNIST.Discharging3

Validation against discharging experiment 3

Information

This example is to validate the developed ice tank model for discharging mode using data generated from experiment 3. The outlet temperature setpoint is set to 2 degree below the measured temperature because the measurement data was taken when the bypass was fully closed. In this way, the implemented model will automatically close the bypass valve during charging.

Extends from Buildings.Fluid.Storage.Ice.Validation.ExperimentNIST.BaseClasses.PartialChargingDischarging (Base example).

Parameters

Modelica definition