Accomodation Air-Conditioning with the Australian Navy

This vessel undergoes an EMP (External Maintenance Plan) every year. This work is carried out on Garden Island Perth every second year and Garden Island Sydney every other year. Cool Technology has worked on both of these EMP’s and receives on average 14 TRS’s (Technical Repair Specification) work packs ranging from galley fridges to accommodation air-conditioning system and cleaning the accommodation, galley, toilet and laundry ductwork. The main contractor for this project is ASP Ship Management who coordinate the tasks, issue the TRS’s and oversee the trades. The work must be completed within 5-6 weeks of commencement and can involve 2-3 crews working on separate projects at the same time. There is a large focus on OH&S/Safety and documentation compliance. The list of jobs for this EMP 20 were:

• Service the Refrigeration Containers 
• Clean the Main Accommodation, Galley, Laundry and Toilet Duct systems
• Service the Main Accommodation Air-conditioning system. 
• Carry out RAS MPMI. (Calibrations)
• Service the NAV and DSE Air-conditioning system.
• Service the Galley Fan Unit.
• Service the Produce Compressor No1.
• Service the Produce Compressor No2.
• Service the Ready to use and Under Bench Fridges.
• Nav and DSE MPMI(Calibrations)
• Carry out ECR MPMI (Calibrations)
• Carry out Accom AC MPMI (Calibrations)
• Carry out Provisions MPMI (Calibrations)
• Service the Accommodation Container Air-conditioning system.

In this Case Study we will focus on the work carried out on the main accommodation air-conditioning system.

CoolTech undertook the following work:

• Adjust or replace compressor drive belts and inspect condition of pulleys and bearings.
• Adjust/replace ahu no.1 fan drive belts. 
• Inspect pulley condition, alignment and bearings.
• Adjust/replace ahu no.2 fan drive belts.
• Inspect pulley condition, alignment and bearings.
• Check galley fan cooling unit bearings for unusual noise or excessive running temperature.
• Change compressor oil & inspect / replace oil filter
• Record compressor suction and discharge pressures, number of banks loaded and operating current of compressor.
• Stop compressor and conduct compressor (valve leakage) pressure drop test
• Clean and inspect ahu no.1 fan impeller
• Clean and inspect ahu no.2 fan impeller
• Clean and inspect galley fan cooling unit fan impeller
• Check functionality of crankcase heating element
• Calibrate gas leak detector
• Dust off ahu no. 1 humidistat hair element
• Dust off ahu no. 2 humidistat hair element
• Clean and conduct inspection of ahu no.1 steam components
• Clean and conduct inspection of ahu no.2 steam components
• Clean, test and conduct inspection of galley fan cooling unit heater elements.
• Clean and inspect ahu no.1 steam inlet strainers and return steam traps.
• Clean and inspect ahu no.2 steam inlet strainers and return steam traps.
• Check condition of ahu no.1 humidifier system steam components and test operation.
• Check condition of ahu no.2 humidifier system steam components and test operation.
• Change compressor suction and discharge valve rings‍

1 x York CMO28. 8 Cylinder Reciprocating Compressor

1 x ABB 60KW 380V Motor

1 x CRKC502320 Marine Condenser 

2 x AHU rooms. Each with a 2 stage evaporator and belt driven fan cowling. 

1 x HDEF- RCC1HD Controller

AHU’s

Our first task was to complete all the inductions for ASP and Garden Island. Once onboard we isolated and double tagged AHU 1. Tagging out onboard Navy vessels is a long and time-consuming process. The mechanic along with an authorised Navy personnel are required to complete the paper work. Fill in the Tag Out Danger Tags and fit them to the switchboard that services the piece of equipment that is isolated. This tag can not be removed by anyone but the people that placed it there or their immediate supervisors. This task must be carried out for every piece of equipment that is serviced. Once Tag-Out is completed the AHU impellers can be inspected and cleaned along with the steam inlets, humidistats and steam inlet strainers. When we completed all these tasks, we untagged AHU 1 and set it to work. Then repeated the process on AHU 2. One AHU must always be kept running at all times to ventilate the accommodation.

Compressor

Moving down to the engine room where the Airconditioning plant is located is a difficult task. The stairs are very steep and slippery and great care needs to be taken when carrying tools. We tagged out the AC plant and decanted the refrigerant from the compressor and liquid line drier. We removed the heads from the compressor and replaces the suction and discharge valve rings. We reinstalled the heads and replaced the oil in the compressor. We then replaced the liquid line drier, once that task was completed, we evacuated the compressor and drier and opened the system up. 

Set to work

With AHU 2 open to the system we ran the compressor. We could now check the pumping capacity of the compressor and set the unloaders. We checked all the pressure cut-out switch and safety’s We set the superheat on the TX valves for AHU 2, switched the system over to AHU 1 and repeated the process. We encountered some problems with the programming of the RCC1HD Controller that took us a few days to overcome. 

Galley cooling unit fan impeller

The Galley cooling unit is located in the AHU room. We tagged this unit out and removed the fan from the cooler. We replaced the bearings and cleaned the impeller. We then reinstalled the fan back into the cooling unit and got the tags removed. We could then set to work. 

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The above TRS was only one of 14 jobs we carried out and it required approximately 2,000 Man hours to complete. We came across many instances where further work was required and submitted a CCP (Contract Change Proposal) Once the CCP was approved we completed the task. As we completed each task a Closing Report along with the SWMS was submitted to ASP. Upon receipt of the closing report the Navy carried out an inspection of the work carried out. All the tasks were carried out to the satisfaction of the NAVY and ASP.