Experience in Design and Implementation of CO 2 Cooling Control Systems

Experience in Design and Implementation of

CO2

Cooling Control Systems

Lukasz Zwalinski PH/DT/PO - Cooling

Detector Seminary 11th October 2011 L.Zwalinski – PH/DT/PO

Presentation overview

Introduction

CO2 cooling systems control principle

Control system standardization approach

CO2 cooling test stands at CERN 2kW CORA – ATLAS and CMS (PH-DT-PO)

100W TRACI – ATLAS & LHCb (PH-DT-PO)

2kW CO2 SR1 – ATLAS (EN-CV-DC & PH-DT-PO)

What’s next?


Introduction

Why CO2?

Allows very small tubing (material budget)

High heat transfer coefficient

High thermal stability due to the high pressure

Where currently successfully used? AMS-TTCS (Tracker Thermal Control System)

Q = 150 WT = +15 ºC to -20 ºC

LHCb-VTCS (Velo Thermal Control System)Q = 1500 W (2 parallel systems of 750 W)T = +8 ºC to -30 ºC

CO2 cooling systems under development

ATLAS IBL

CMS - tracker upgrade

KEKb-Bell 2


Principle

DetectorCooling plant

Warm transfer

Chiller Liquid circulationCold transfer

2-Phase Accumulator Controlled Loop method:

(LHCb)

Refrigeration method:(Atlas)

Vapor compression system

Pumped liquid system, cooled externally

Hea

terCompressor

Pump

Compressor

BP. Regulator

Liquid Vapor

2-phase

Pre

ssur

e

Enthalpy

Liquid Vapor

2-phasePre

ssur

e

Enthalpy Cooling plant Detector


Introduction to control CO2 cooling system

Accumulator

Cooling regulated by pulse modulated control valve

Heating – regulated by pulse modulated heater

Chiller

Pump

Heaters

Cooling

Pump

1 4

5

32

6

Heating

Control valves

Gas

Pre

ssur

e

Isothermal line

Enthalpy

Liquid

3

4&56

2

17

2-phase(Evaporation)

3

4&56

2

17

3

4&56

2

17

7


Control system standardization approach

Why do we need standardization? To design and fully test complete base model of future detector cooling systems

(mechanical/electrical/control)

Provide a control system in accordance with CERN standards

Provide a system easy to integrate with Detector Control System

How do we apply it? Common and easy to manipulate human machine interface for PLC based systems with long

term data archiving, trending tools, alarms history and diagnostic tools. PVSS as supervision

and data acquisition system well known and widely used at CERN in LHC and in Detector

Control Systems (ATLAS)

Industrial control/electrical components: Siemens/Schneider/Phoenix/PR electronics

UNified Industrial COntrol System framework – object orientated framework for PLC and

PVSS programming


Standardization approach

TE-CRG-CE

EN-ICE

PH-DT-POPH-DT-DI

EN-CV-DC

CO2

Industrial electrical componentsControl hardware equipment

Electrical diagnostic toolsSiemens PLC standard

Schneider PLC standard

Recipes componentNew software components:• on-line pressure enthalpy diagram• one button PVSS system start/stopAlarm diagnostic

UNICOS frameworkIEC61512-1 standardPVSS


Control system design and implementation

Functional analysis

Electrical design

Electrical assembly

Component selection and ordering

SCADA programming

Additional toolsdevelopment

PLC programming

Project organization

Work flow for control

system design and

implementation

UNICOS

Process concept

User manual

Commissioning

Pump

Compressor

Commissioning

User manualAssembly


CORA 2kW – control system architecture

SIEMENS PLC

Electrical / signal

connections

GPN

OWS OWS OWS

Power perm

it

Test structure

TT protection

B21

B158

CO2 Research Apparatus - CORA Siemens S7 319 PLC (building 158)

PVSS 3.8 data server on Windows PC (building 21)

UNICOS framework (32AI, 4AO, 32DI, 32DO, 7 closed control loops)

Experiment power redistribution box with temperature protection


CORA 2kW – control system



Alarm diagnosticAlarm list

+ email & SMS alarm notification



PLC graphElectrical diagnostic

System stepper


CORA 2kW – accumulator control

To avoid of overheating(dry out prevention)

To keep sub cooling condition

PT1103

Acc. Tsp

PC1104PID

MV

SP

EH1104Out High limit

Out Low limit Low limit

High limit

0%

Dynamically calculated f(Rth)0 ÷ 100 %

PC1105PID

Out Low limit

Out High limitMV

SP

Psat(Tsp)

CV1104

Low limit

High limit

Dynamically calculated f(sub-cool)0 ÷ -100 %

0%

OutO

OutO

IF Out1 + Out2 > 0 Then

EH1104 ActiveElse

CV1105 Active

Analog Digital Object


PWM

0÷100%PWM

0÷100%


CORA 2kW – pressure, enthalpy online diagram

PVSS control extension:- Real time calculation- Connection to external data base

REFPROP 8- 11 constantly plotted isotherms- Possibility of displaying isotherms in

measured points- Proposed as future JCOP component

Point 1 - Outlet of experiment lines Point 2 - Outlet of return line of internal

heat exchanger Point 3 - Pump inlet Point 4 - Pump outlet Point 5 - Outlet of supply line of

internal heat exchanger

This control extension currently is available on Windows machine only!

123

4 5


100W TRACI - concept

Transportable Refrigeration Apparatus for CO2 Investigation

Simplified concept of 2 Phase Accumulator Controlled Loop

To simplify the concept the internal heat exchanger function and the accumulator cooling function are integrated by cooling the accumulator with the pump outlet flow. The concept is called Integrated 2PACL(I-2PACL).

The simplified concept was patented on Friday September 9th, 2011.

Pressure

Accumulator PLC Control

(Heat and cool)Chiller

Liquid Pump

Condenser

Temperature

2PACL

Pressure

Accumulator Controller (Heat only)

Chiller

Liquid Pump

Condenser

I-2PACL

I/O Number

TT (PT100) 4

TT (TC type K) 3

ΔT 1

PT 3

ΔP 1

EH 3

Compressor 1

VL 1

Pump 1


100W TRACI – control system

Requirements:• Simplified control concept = NO PLC!

Solution:• On-shelf industrial control/electrical components• All logic realized by relays, universal transmitters and 1 PID controller• Integrated National Instruments DAQ• LabVIEW user interface, open to add experimental part• No need to have PC/PVSS to run the plant

-50

-40

-30

-20

-10

0

10

20

30

9:36 10:48 12:00 13:12 14:24 15:36 16:48 18:00

Tem

para

ture

[°C]

Time

TRACI operation test

Temperature after condenser

Temperature on condenser surface

Temperature on condenser surface

R404As saturation temperature

CO2 saturation temperature


100W TRACI – first results and future improvements

Future control improvements:• Reduce electronics to micro-controller • Skip some functionalities in control• Replace pump to be fixed speed

(no frequency control)• More powerful chiller

-40 -38 -36 -34 -32 -30 -28 -26 -24 -22 -200

50

100

150

200

250

300 TRACI operation with minimum heat load

Temperature [oC]

Heat

Loa

d [W

]

Goal: 100W @ -40oC to +20oC• -40ºC not met– More heatleak than expected

• 1.5x larger chiller possible in same mechanical envelope

150W heat load 150W heat load

accumulator design

dummy load design

primary chiller

PLC brand


CO2 SR1 concept – collaboration with EN-CV-DC

Differences to CORA

CO2 SR1 - control system


Main user SCADA panelSchneider PLC (EN-CV-DC hw. standard)

Modifications

Architecture

based on CORA experience

1. CO22. Mélangues3. Thermosiphon 2kW

CERN TN

CERN Terminal Server

CERN GPN

OWS OWS OWS

CPU + I/O cards CPU + I/O cardsCPU + I/O cards

CO2 Melangues Thermosiphon 2kW

UNICOS based PLC software

UNICOS based PVSS implementation

PROFIBUS flow meters

One central PVSS data server in BE-CO for all “test” applications Access to all applications form one terminal server PVSS accesses control with personal NICE login and password All applications in Technical Network

CO2 SR1 PVSS interface

Stepper


Interlocks diagnostic

Accumulator limiters

Recipes

Modifications

Electrical diagnostic


Modifications

Functional analysis: process actuator operation logic system states and transitions alarms computed parameters recipes parameters

https://espace.cern.ch/CO2-SR1/Shared%20Documents/Control/CO2_SR1_Functional_Analysis.doc

Functional analysis and control

PT1104

Acc.TSP Tsp

PC1104 MV

SP

EH1104

Out High limit

Out Low limit

Low limit

High limit

Dynamically calculated f(Rth) 62.5% ÷ 100 %

Psat(Tsp)

CV1104

Low limit

High limit 0% Step 1&2

OR Dynamically calculated f(sub-cool)

in STEP 3 0 ÷ 45 %

OutO

I F 0%<OUT<49.5% Then

CV1104 ACTIVE Cooling action

Else IF 50.5%<OUT<100%

EH1104 ACTIVE Heating action



4-20mA

0÷100%%

PWM

0÷100%%

splitter

Acc.Psat Tsp

No action 49.5%–50.5%

Heating EH1301

Cooling CV1201

0% 0% 100% Controller

output order

Object position request

100%

50% 62.5% 45%






What’s next?

MARCO: Multipurpose Apparatus for Research on CO2

• 2PACL concept• Temperature range from -40C to room temperature• Capacity 1kW• Base for future ATLAS IBL and KEKb-Bell 2 detectors

Control system approach:- Control system to be easily integrated in DCS- Siemens PLC- UNICOS framework- Integrated control panel (to be introduced, currently not supported solution) - Use recipe component- Select tested in previous CO2 cooling units electrical and control components

Status:- PLC components delivered- Electrical study in progress (electrical schematics)


Conclusions

Existing test CO2 cooling stations at CERN:

CORA operational

TRACI 1a(LHCb) and TRACI 1b(ATLAS) operational

CO2 SR1 under commissioning

MARCO under construction

CO2 cooling systems in HEP experiments:

AMS

LHCb


CORA 2kW – experiment inlet enthalpy control

Øm = Qexperimet / (h5 - h4)

Qheater = (hrequested - h3) * Øm

It is not possible directly control the enthalpy in a PID loop.

The enthalpy can be derived from measured pressure and temperature only when the state point is present in the liquid phase which means that measured temperature should be at least 20C lower than calculated Tsat .

PLC is calculating enthalpy from measured temperature TT1104 and pressure PT1102 and it’s ON only if TT1104 -20C ≤ Tsat(PT1102) is true.

PT to H conversion

50

100

150

200

250

300

0 10 20 30 40 50 60 70 80

Pressure (bar)

Enth

alpy

(kJ/

kg)

-50-45-40-35-30-25-20-15-10-50510152025

Measured pressure => look for p_up & p_down in table and associated A,B,C,D up& down constants

h_up := A_up*(input_TT**3) + B_up*(input_TT**2) + C_up*input_TT + D_up;

h_down := A_down*(input_TT**3) + B_down*(input_TT**2) + C_down*input_TT + D_down;

//Enthalpy search, interpolation

Output:= ((h_up-h_down)*(input_PT-input_PT_down)/(input_PT_up-input_PT_down))+h_down;


CORA 2kW – experiment inlet enthalpy control

25

CO2 allows small tubing

Why?Large latent heat & Low viscosity & High pressure

Allow high pressure drop

Allow low flow Low pressure drop

Low pressure drop Lower pressure drop

Allow very small tubing

Latent Heat of Evaporation

(KJ/

kg)

Bet

ter CO2

C3F8

Bet

ter CO2

C3F8

0

100

200

300

-40 -20 0 20Temperature (ºC )

Liquid Viscosity

Temperature (ºC )

(Pa*

s) Bet

ter

CO2

C3F8

1e-4

2e-4

3e-4

4e-4

5e-4

-40 -20 0 20

But with very high heat transfer capability!