This document summarizes a project to address failures of automation hardware on liquefied natural gas carriers due to high ambient temperatures. Testing found that field stations located in engine rooms were experiencing temperatures over 50 degrees Celsius, causing electrolytic capacitor failures. A trial installation of a thermoelectric cooler on one field station reduced temperatures but not enough. Refrigerant coolers of 1.5 kilowatts were then selected, installed on the trial station, and found to maintain temperatures suitable to halve failure rates according to the Arrhenius equation. The project will now install similarly sized refrigerant coolers on all field stations identified as needing cooling across the Qflex fleet.

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SHIP AL THUMAMA
FLAG MARSHALL ISLANDS
PORT OF REGISTRY MAJURO
YARD NUMBER HHI 1862
CLASS DNV
GT 136355
IMO 9360843
PROJECT IAS Climatic Control to be fitted to Qflex Fleet
REPORTED BY OLIVER BATT (VESSEL MANAGER / ELECTRICAL SPECIALIST)
INTRODUCTION
SINCE DELIVERY OF THE VESSEL NYK HAS EXPERIENCED AN EXCEEDINGELY HIGH RATE OF
FAILURES OF THE HARDWARE ASSOCIATED WITH THE AUTOMATION SYSTEM. ESPECIALLY
THIS HAS BEEN THE RMP400 UNITS AND RCU400.
SCENARIO AND OBSERVATIONS
The vessel is one of 14 Qflex class which has been equipped with Kongsberg DACS
Automation. DACS is generally robust and performs well however failures of the IO modules
have experienced a low mean time between failures (MTBF) which have been causing
unexpected costs outside the budgeted expectations, and concern with regards to failure to
control critical machinery.
All Qflex vessels have the design concept of localised process stations for the automation
circuitry, seeing the field stations located all around the engine room. This has the benefit of
reducing cable lengths at the point of new build, but has the consequence of placing the
process stations in the high ambient temperature of the engine room. This design concept
differs from some LNG ships in the NYK fleet that houses all IO field stations in the climatic
controlled areas of the engine control room.
Analysis of the purchasing system shows a vast increase of unexpected expenditure with
regards to IO where the field stations are located in a non-climatic controlled space.
Specifically Al Thumama was experiencing failures of the RCU400 and RCU 500 modules,
each with a unit cost of 1800USD and 2400USD respectively. Typically failures were
numbering 15 to 20 pcs per year.
Root Cause Analysis
Root cause analysis was undertaken by electronics specialists Paramount Electronics in the
UK.

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The RMP and RCU units were both investigated, and the actual internal circuitry for the IO
was found to be all satisfactory. The problem was attributed to a small internal power
supply located in the top portion of each card.
The power supply consists of a pair of electrolytic capacitors and one bead tantalum
capacitor to smooth the DC supplies after rectification. Paramount noted these to be
failing, and upon closer inspection, the dielectric liquids had all dried up causing the failures
on both types of module through open circuit capacitors. Interestingly there was no damage
caused to the IO circuitry.
Figure 1
Electrolytic Capacitor cross section
Figure 2
One of the defective RMP 400 units – failing capacitors fit just under the top grill
NYK investigated this and undertook a thermal imaging survey of the field stations. Figure 3
shows the image for FS71. Especially we looked at process station FS71 which is located
close to the GCU in the funnel casing, and attributed to be the hottest ambient area on the
vessel. We also asked Kongsberg to fit a PT100 probe to monitor the internal temperature of
field station 71 so we could monitor the internal temperature.

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We noted with trends from the PT100 and the thermal imaging report that the RMP and
RCU units were operating at temperatures often in excess of 50 degrees Celcius.
Figure 3
Thermal Imagine report from FS71
NYK recognised the Arrhenius equation. This was developed on a set of investigations based
on a single electrolytic capacitor operating in differing temperatures. This states ‘if you
reduce the temperature by 10 degrees K, the failure rate halves’.
Figure 4
Arrhenius Equation graphically depicted

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Evidence shows the automation electronics were subjected to temperatures far in excess of
50 degrees Celsius, and climatic control of their operating environment would reduce MTBF.
The electrolytic capacitors were therefore noted to be the root cause of the failing cards.
This raised concern that failures of automation may also cause unreliability of critical
equipment and a compromising the vessel in a dangerous sea passage such as Singapore
Straits, or the Suez Canal.
Solution
The problem was discussed Kongsberg UAE, whom provided written consent, that in a
controlled manner KM would have no objections to NYK running trials with a view to fitting
coolers on every field station cabinet exposed to a high ambient temperature.
It was mutually agreed that the design authority of the Kongsberg DACS would be
maintained by keeping coolers OEM supply, ie the same manufacturer as the Kongsberg
cabinets. As a result cooling products from Rittal who manufactured cabinets for Kongsberg
were reviewed.
It was agreed by all parties that the trial field station would be FS71 due to it experiencing
the highest ambient temperatures.
NYK investigated different types of cooler that are presently available. There is mainly two
different options available, thermo electric type plate cooler with no moving parts working
on the theory of temperature differentials through currents passing two dissimilar metals,
or a conventional refrigerant cooler with circulating fans.
Although in document 179167/D Kongsberg do not give the exact operating temperature
range or any recommendations for the RMP / RCU units, they do state they a typical heat
dissipation of 10 W. Assuming 10 of these are installed in each cabinet along with their
associated equipment, we could expect approximately 100W of heat dissipation.
After some review of the cooling ability and manufacturers graphs for performance, it was
decided to trial a 100W thermo electric type FS71. This was supplied by Routeco / Rittal and
fitted by ships staff.
Consideration was given to condensate drains so absolutely no moisture could get into the
RMP RCU units, and the power has been carefully selected from a lighting distribution close
by the field station, so as if the cooler failed it would not trip the associated field station.

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Figure 5
Thermo electric Cooler Performance chart and installation in FS71
With the PT100 internally fitted to the cabinet we were able to trend the performance of
the units Dt, however the summer in the Gulf 2016 was particularly hot, and the trends
observed found a Dt of approximately 5.8 degrees Celsius . Observations from the DACS are
shown below.
Figure 6
Trial Thermo electric cooler showing 5.8 degrees C Dt
Although the equipment heat dissipation was 100 Watts, the ambient temperature was not
really taken into consideration. The exceedingly high ambient clearly required much more
powerful cooling.
After some technical review with Routeco and Rittal, it was decided that the internal volume
of the cabinets was also too great for the single thermo electric type cooler. Rittal reviewed
our installation and ran a set or more complex calculations taking into consideration:-
Cabinet Ambient
Cubical size
Required temperature required inside
Wattage of the equipment in each cubical

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This lead to two further engineering options being available:-
1. Bank ten thermo electric coolers in the front of each cabinet
2. Fit 1 higher wattage 1.5KW refrigerant based cooler
Option 1 was reviewed as there are no moving parts in the thermos electric cooler however
costs of this option would have been prohibitive.
Option 2 was reviewed and judged acceptable as the preferred solution.
A further refrigerant cooler type was subsequently purchased and fitted.
Figure 7
New Refrigerant cooler installed in FS71 to replace thermo Electric Cooler
Under trials the 1.5KW refrigerant cooler can be seen in the above diagrams to be operating
to it exact specification and satisfactory for our requirements.
Presently we are experiencing a Dt of 14.4 degrees, and based on the Arrehenius equation,
should more than half the failure rates of the I/O.
The temperature setting of the cooler has been made with longevity of the refrigeration
compressor, longevity of the RMP RCU units and maximum overall reliability of the DACS
system.

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Figure 8
Before operation the Cabinet temperature noted to be 44 degrees Celsius
Figure 9
With a set point of 30 degrees Celcius Dt of 14.5

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PROJECT PLAN
With the engineering solution suitably proven, a review of the field stations that would
require cooling units on board the Qflex was made.
SYSTEM PS POSITION COOLER (YES or NO)
CARGO
FS-31 DACS I/O Cabinet Room - A deck NO
FS31-1 Side Passageway STBD YES
FS31-2 Side Passageway STBD YES
FS31-3 Side Passageway STBD YES
FS-32 DACS I/O Cabinet Room - A deck NO
FS32-1 Cargo Mootr Room YES
FS-33 DACS I/O Cabinet Room - A deck NO
FS33-1 Side Passageway PORT YES
FS33-2 Side Passageway PORT YES
FS-34 DACS I/O Cabinet Room - A deck NO
FS34-1 Engine Room bottom floor YES
ENGINE
FS-41 LV Room STBD NO
FS41-1 Engine Room 4th
Deck YES
FS41-2 Engine Room bottom floor YES
FS41-3 ECR NO
FS-42 LV Room STBD NO
FS42-1 Engine Room 2nd
Deck YES
FS42-2 DG #1 & #2 Room YES
FS-43 LV Room PORT NO
FS43-1 Engine Room 2nd
Deck YES
FS43-2 Engine Room 4th
Deck YES
FS43-3 Engine Room bottom floor YES
FS-44 LV Room PORT NO
FS44-1 Engine Room 3rd
Deck YES
FS44-2 DG #3 & #4 Room YES
FS44-3 Funnel Casing - A Deck YES
MISC
FS-61 Cargo Motor Room YES
FS61-1 Cargo Motor Room YES
FS61-2 Cargo Motor Room YES
FS61-3 Cargo Motor Room YES
FS-71 Funnel Casing - GCU floor YES

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The remaining parts of the project will be executed on a turnkey fixed cost basis.
1. A specification for the installation of each cooler will be made detailing the exact fit,
source of power, and location of condensate drain if required. (Available 15th
December)
2. Routeco have quoted for vessel material and consumable kits to be provided for
each ship. These will consist of the coolers, individually marked for each field station,
and all tools and consumables required to complete the installation on every vessel.
Quotation is attached.
3. EMCS have been approached to supply the man power to install the coolers, on a
flexible daily rate. Quotations attached.
COST SUMMARY – QUOTES IN APPENDIX 5 & 6
Coolers, Tools, Hardware 45203.25
Labour 7707.34
Total 52910.59
Budget 60000.00
Balance of budget 7089.41
USD rates from XE Currency 29/11/16
MAINTENANCE AND PMS MEASURES
 Appendix 1 includes MTBF estimations
 3 monthly the filters will need to be changed, on every cooler – approximate 1 hours
work in total
 Evaporator fans to be changed in bulk at 10 years, dry dock 2027 based on the
present duty.
 1 complete spares kit to be carried on every vessel.

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ALARMS AND MONITORING
The Coolers have intelligent diagnostics and can have programmed relays to interface with
DACS to prevent the need for an electrician to make a round to check they are working.
1. Relay 1 will be linked to the automation system by means of a common alarm,
drawing attention for the electrician to attend a cooler.
2. Relay 2 will alarm if the airflow across the evaporator is reduced indicating dirty
filter.
3. PT100 will be installed in every DACS field station FOC by Kongsberg. NYK to provide
sensing probes.
The DACS connections will be made during the 2017 docking, and a separate specification
will be written and agreed with KM.
Reported by Oliver Batt Vessel Manager………………………………………………………………………………
Reviewed by …………………………………………………………………….
Review and Approval for Purchase ………………………………………….
Appendices (Removed):-
1. MTBF from Rittal
2. Calculations for power of the cooler
3. RMP400 data sheet
4. Typical Cabinet dimensions and housed equipment
5. EMCS Labour quote for installation
6. Routeco / Rittal Quotation