1. Heat to air update
August 9th, 2017

2. Outline How heat to air theory and assumptions Experimental setup
Flow trough heater
PID control
Test plan
Heat loss in loads
Test results
August 9th, 2017

3. Measurements and theory
Heat to air ‘measured’
Assume all heat from heater goes to water or air
Tout
Tin
T component
SAS4
Heat to air theory
load
August 9th, 2017

4. System overview SAS4 There are 2 new SSR boxes
SSR1 is connected to SAS heaters and the new flow-through heater.
To heaters
SAS1 SAS2 SAS3
RTD out
RTD in
Flow meter CV
pressure
Chiller
RTD Flow heater in
RTD Flow heater out
HEATER
LabVIEW Software
SSR
heaters
NI 9472
8-Ch
24 V Logic output
240 Vac
August 9th, 2017 4
PRV = pressure regulating valve
PT = pressure transducer
CV = control valve
RTD = temperature sensor
HV = hand valve

5. Flow-trough heater
The heater is connected in a vertical position to the hydraulic circuit.
The temperature measured after the heater is used as the process variable in the PID controller implemented in LabVIEW
The heater is provided by Loval Oy
August 9th, 2017

6. PID
∆T (°C)
SAS in
0.13
Chiller
0.90
During the first heat to air tests, the fluctuations in the inlet temperature affected the heat to air measurements.
A flow trough heater was installed to control fluctuations from the chiller
A PID controller was implemented with labVIEW.
The PID was tuned both manually and with an automatic PID tuner
The manual tuning gave best results, and the effect is shown above
(Tuning numbers and constants in extra slide)
August 9th, 2017

7. Testplan
Heat to air test during steady state were completed for tree different ambient temperatures, with low (0.3m/s) and high (0.8m/s) air speed .
Tests were completed without and with isolation.
Tin (⁰C) 27
Heater (W)
866
mass flow (l/s)
1.35
Isolated SAS4
Ambient (⁰C)
Air speed (m/s)
No isolation 20
0.3
0.8 30 40
With isolation
August 9th, 2017

8. Heat loss in loads During new heat to air test it was found that
Qtot ≠ Qair + Qwater
Occurred after installing the loads. We found that heat is lost trough the loads (and wave guides).
Installed new RTD sensors before and after loads to measure the loss.
 for the newest results (results with isolation) the heat loss in the loads were measured and accounted for in the heat to air calculation.
 For the tests completed before the loads sensors were installed, the same correction factor was applied to the results.
The correction factor for the loads without isolation should be measured and accounted for .
August 9th, 2017

9. Heat loss Loads Ambient ≈ x ⁰C ≈ 37- 40⁰C Ambient under ≈ 36-37⁰C
Gurder
≈ 35⁰C
Floor
≈ 30⁰C
August 9th, 2017

10. Results
August 9th, 2017

11. Numbers to remember Chiller settings Ambient temp (oC)
Chiller setting (oC) / Air 03m/s
Chiller setting (oC) / Air0.8 m/s 20
25.0 30
22.0 40
15.0
PID setting
One stucture
All 4 stuctures P 15
110 I
0.3
0.2 D
0.05
Other settings settings
Flow Scaling 50
Setpoint
27.125
Scaling factor SAS heaters
0.482

12. Thank you for your attention
May 31th, 2017

13. LabVIEW
August 9th, 2017

14. LabVIEW
August 9th, 2017

15. LabVIEW
August 9th, 2017

16. aa
There are 2 new SSR in total. Connected to all SAS heaters for T0.1 and the flow-through heater.
August 9th, 2017

17. PID : Proportional gain, a tuning parameter
: Integral gain, a tuning parameter
: Derivative gain, a tuning parameter
: Error
: Time or instantaneous time (the present)
: Variable of integration; takes on values from time 0 to the present .
* LabView software
August 9th, 2017 17

18. PID tuning
Tuning
The process of setting the optimal gains for P, I and D to get an ideal response from a control system is called tuning.
There are different methods of tuning of which the “guess and check” method and the LabVIEW automatic tuning VI ( Ziegler Nichols method) has been tried out.
The power range provided by the flow-trough heater is W.
Manual tuning tests:
Test.nr
Range on heater
Controller type P I D
Test 1:
0-80 PI 50
0.1
Test 2:
1000
Test 3:
3000
Test 4:
10000
Test 5:
0.5
Test 6:
PID
Test 7: 18

19. Automatic PID tuning
Performing interactive auto tuning in a dialog box that you use to configure the process.
Includes the Auto tuning Wizard in addition to the basic PID algorithm.
The PID controller was tunes for sevreal output ranges of the flow-trough heater. See table
Exluded derivative response in the first tests:
The derivative component causes the output to decrease if the process variable is increasing rapidly.
Highly sensitive to noise in the process variable signal
If the sensor feedback signal is noisy or if the control loop rate is too slow, the derivative response can make the control system unstable
Automatic tuning:
Test nr.
Range on heater
Controller type P I D
Test 1:
0-30 PI
3.194
Test 2:
0-50
1.651
Test 3:
0-65
1.447 19

20. BD test Test name Valve range Test1 43-100 Test2 50-100 Test3 60-100
70-100
Test5
80-100