Heating, ventilation, air conditioning (HVAC)

Onboard ships, the most commonly used chiller systems are vapor compressed refrigeration cycle chillers, comprising compressor, condenser, expansion or flow control devices, as well as evaporators.

 The most commonly used compressors are screw or centrifugal types, with an indirect central cooling system  design. This means that secondary circuits are also installed, where the condenser is cooled via a seawater cooling circuit and the chilled water circuit (evaporator side) uses cold water to cool the air handling units.

Main benefits are the following:

• Installing VFDs on chilled water pumps and on the evaporator cooling side provides accurate control and energy consumption based on process demand. In most cases, the typical payback time is less than one year. On average, savings are between 30 – 40% of total power consumption.

• Using VFDs for supply and exhaust fans, rather than relying on inlet vanes and two-speed motors, generates energy savings in every case. The payback time is less than one year.
  

• In theory, installing a VFD on a centrifugal compressor can reduce power consumption by as much as 25%. This depends heavily on the chiller plant’s control strategy. The investment cost of a chiller upgrade is relatively high, generating a payback time of between 2 – 2.5 years.

In passenger vessels, the heating, ventilation and air conditioning (HVAC) system is the second largest consumer of energy after propulsion.

ABB ARKM20 products enable customers to monitor and give insight into the efficiency of existing HVAC systems as well as manage the chiller setpoints automatically. By comparing monitored results, the chiller and HVAC efficiency improvement can be determined and measured according to industry HVAC efficiency targets.

The ABB ARKM20 interfaces on existing HVAC and chiller networks, collects and analyses data, manages chiller set-points and provides information to operators and management on performance. Crew and management awareness about the HVAC energy consumption is improved by reporting interfaces both locally to operators and via web interface to management.

The ABB ARKM20 Onboard system will securely send integrated information to ABB ARKM20-Online, a cloud based database and reporting tool. The user can monitor and analyze the vessel with a wide variety of possibilities. 


The main benefits are the following:

• Chiller energy consumption can be reduced up to 25%
• Improved efficiency, especially at part-load
• Negligible start-up current, Accurate capacity control and the equipment operates at lowest motor speed
• When multiple chillers are installed, a new high efficiency chiller can be used as a lead chiller to take care of the variable load and existing conventional chillers as backup operating at near full-load whenever they come on