An overview

LIQUID COOLING LIBRARY

Modelon © 2016

• What is Liquid Cooling Library?

Key features & capabilities

• Example use case

Vehicle thermal management

• Library contents

Fluid components

Medium property models

AGENDA

• Modelica library by Modelon

• High performance modeling of incompressible flow, including closedcircuits. Real-time applications.

• Suitable for a wide range of applications, ranging from automotive and aerospace to industrial equipment and process industry

• Highly customizable; Realize non-standard circuits and add in-house IP

WHAT IS LIQUID COOLING LIBRARY?

• Large set of fluid component models

Generic, customizable components

Geometry based components

• Medium property models

Water

Aqueous solutions of glycol, alcohols, glycerol, ammonia, chlorides and salts

Jet fuels and motor oil

• Plug-and-play compatible with other Modelon libraries for thermal management

KEY FEATURES

• Cooling systems for automotive and process industry

• Engine cooling

• Battery thermal management

• Component selection

• Pump dimensioning

• System performance studies

• Transient response studies

• Easy realization of non-standard circuits

• Support control system development and evaluation

KEY CAPABILITIES

Power [W]

Position [0-1]

1.53 336.1 0.4

p(bar) h(kJ/kg)

T(degC) m_flow

80.1

engineVolume

radiator

1.50 214.5 0.2

p(bar) h(kJ/kg)

T(degC) m_flow

51.0

resistance2

expansionVolume

V=0.008

Gas

p T

gasPressureBoundary

T . m

gasFlowBoundary

heatSource

Q

pump

35088

Main

Bypass

1.50 377.7 0.2

p(bar) h(kJ/kg)

T(degC) m_flow

90.0

ramp2

duration=5

0.568 90.0

25.0

73.7

57.5

41.2

Temperature [degC]

EXAMPLE USE CASES

• Vehicle Thermal Management (VTM)

• Problem: Balancing system level requirements for cooling and energy usage

• Solution: Model-based system design/optimization and control design

• Tools: Dymola + Liquid Cooling Library + Heat Exchanger library

• Easy integration with: Engine Dynamics Library, Vapor Cycle Library, Vehicle Dynamics Library. Also Air Conditioning Library via special adapter.

• Partner: OEM | Work flow: Calibrate & validate component / subsystem models, then build system and exercise over critical drive cycles

VEHICLE THERMAL MANAGEMENT

Coolant loop

Power [W]

Position [0-1]

1.53 336.1 0.4

p(bar) h(kJ/kg)

T(degC) m_flow

80.1

engineVolume

radiator

1.50 214.5 0.2

p(bar) h(kJ/kg)

T(degC) m_flow

51.0

resistance2

expansionVolume

V=0.008

Gas

p T

gasPressureBoundary

T . m

gasFlowBoundary

heatSource

Q

pump

35088

Main

Bypass

1.50 377.7 0.2

p(bar) h(kJ/kg)

T(degC) m_flow

90.0

ramp2

duration=5

0.568 90.0

25.0

73.7

57.5

41.2

Temperature [degC]

• Integrated model for fuel economy and vehicle thermal management

Vehicle model with loads and losses

Vehicle heat loads (engine, friction, transmission)

Lumped engine thermal model

Coolant and oil circuits with possible additions of other thermal fluid circuits

Drive cycles (speed, grade, wind, etc.)

Airflow effects

Key vehicle and thermal controls (fan)

INTEGRATED VTM MODEL

VTM SYSTEM MODEL• Thermal

• Mechanical

• Electrical

• Coolant

• Air

• Controls

SAMPLE RESULTS – DRIVE CYCLE

Boundary – vehicle speed

Boundary – engine torque

Actuator - fan

Controlled temperature

Actuator - thermostat

• Pipes and bends

• Flow resistances

• Volumes and tanks

• Junctions

• Pump and fan

• Heat exchangers and stacks

• Flow modifiers and sources

• Solid heat transfer

• Single-phase coolants and refrigerants

LIBRARY CONTENTS

• Generic pipes with different fidelity and replaceable correlations Lumped or discretized

Pressure drop

Heat transfer

Transport delay

• Components with geometric loss coefficient data: Straight pipes

Circular bend

Mitre bend

PIPES

The library includes loss coefficient data for all geometric components.

Main reference: Internal Flow Systems, D S Miller

GEOMETRIC FRICTION MODELS

Straight pipe loss coefficient Circular bend loss coefficient

The liquid pipe uses transport delay instead of internal control volumes. This is often more accurate for liquid flow at low discretization numbers.

PIPE SEGMENTATION

Temperature profile for 4 volumes

Temperature profile for 4 transport delays

0 4 8 12 16 20

20

40

60

80

100

pipe.T[1] pipe.T[2] pipe.T[3] pipe.T[4]

0 4 8 12 16 20

20

40

60

80

100

pipe.T[1] pipe.T[2] pipe.T[3] pipe.T[4]

• Generic flow resistances Replaceable friction model

• Geometric flow resistances with tabulated loss coefficient data Orifice plate and long orifice

Abrupt contraction and expansions

Flush mounted intakes

FLOW RESISTANCES

• Closed volumes Energy storage

Different port configurations

Heat transfer and solid thermal mass

• Expansion volume

• Open tank

VOLUMES AND TANKS

• Combining and dividing junctions

• Geometric loss coefficient data for many geometries

JUNCTIONS

• Control valves

• Thermostatic valves Two and three-legged

Replaceable friction and opening characteristics

Possible to include hysteresis effects

VALVES

Example thermostatic valvecharacteristics with hysteresis

Pump and fan• Flexible parameterization

Multiple options for pump and fan curves

Heat exchangers• Simplified heat exchanger

models Based on tabulated efficiency

e-NTU approach

• Possible configurations Gas – Gas

Gas – Liquid

Liquid – Liquid

• Stacks Containing 2 to 8 heat exchangers

PUMP, FAN, HEAT EXCHANGERS

BASIC COMPONENTS

The AggregateVolume object calculates the total liquid volume in the system – useful for dimensioning

LCL includes models for single phase coolants and refrigerants. For each mixture, the concentration can be set anywhere between zero and the eutectic composition. List of available media (aqueous solutions):

MEDIUM PROPERTIES

Reference: International Institute of Refrigeration, 2010

• Calcium chloride• Ethylene glycol• Propylene glycol• Ethyl alcohol• Methyl alcohol• Glycerol• Ammonia• Potassium carbonate• Magnesium chloride

• Sodium chloride• Potassium acetate• Potassium formate• Lithium chloride

Media models of motor oil and jet fuel are also available

Templates are predefined test benches for quick set up of own experiments. They include parameters for:• Visulization

• Steady State Initialization

• Aggregated Liquid Properties

Experiments are available to illustrate;• Flow branching and merging

• Individual component tests

• Open fluid networks

• Closed cooling circuits

• Heat exchanger stack test

EXPERIMENTS

Water circuit model with trace component

TRACE VARIABLE

In this example the trace componentintroduced in pipe1 can be followed in the system (in pipe 8 with time delay, and in pipe 10 controlled via valve). step

startTime=40

pipe5

2

pipe3

2

pipe8

2

pipe9

2

pipe10

2

step1

startTime=15

step2

startTime=25

ramp

duration=10

75.0

25.0

62.5

50.0

37.5

Temperature [degC]

• It is possible to visualize the temperature and pressure of the components, the opening of valves and more.

See bath tub example below.

VISULIZATION

• MATLAB

• Python

• Excel

BATCHED SIMULATION

Experiment settings

Parameter modifiers

An example of batched simulation in Modelonproduct FMI Add-in for Excel (FMI-E)

VTM EXAMPLE WITH STACKED HEX

Constant road grade sweep (-0.5 to +2.0 %) at constant vehicle speed

More grade increases engine cooling temperature (top left).Transmission oil cooler thermostat opening (bottom right) affects radiator air inlet temperature (top right)