Cooler Project Ver 1.0 LKIN

29/11/16 QFLEX COOLER PROJECT

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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)

C A

R G

O

FS-31 DACS I/O Cabinet Room - A deck NO

FS31-1 Side Passageway STBD YES




FS32-1 Cargo Mootr Room YES


FS33-1 Side Passageway PORT YES

FS33-2 Side Passageway PORT YES


FS34-1 Engine Room bottom floor YES

E N

G I

N E

FS-41 LV Room STBD NO

FS41-1 Engine Room 4th Deck 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


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

M I

S C

FS-61 Cargo Motor Room YES

FS61-1 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

Documents

Cooler Project Ver 1.0 LKIN