Cooling and chilling units (ACU, AMC)
Our marine gas oil cooler units (ACU) ensure that the viscosity of marine gas oil (MGO) is at a suitable level for an engine. Low-sulphur fuels, such as MGO, generally have a low viscosity and do not usually meet the minimum viscosity requirements of main engines. Viscosity can be increased by cooling the oil with our series of coolers.
Cooler units contains a plate or a tube-type cooler, a three-way water-control valve, a temperature transmitter on the MGO outlet line for mA signal linked to the engine control room, an optional viscosity sensor (range 0-10 cSt), and all necessary fittings and valves for installation and operation.
Cooling water for ACUs is delivered from either the ship’s low temperature (LT)-water, seawater cooling system or from a separate Auramarine modular chiller (AMC) unit. The heat from the MGO fuel is transferred to the cooling water via the unit’s heat exchanger.
ACU modules have a built-in mixing function control valve, which is based on fuel outlet temperature. It controls the flow of cooling water (in LT-water models) or MGO flow (in seawater model). With this level of control, fuel temperature response is immediate and accurate. The unit’s temperature controller is factory set at a temperature change rate of 2°C/min to prevent thermal shock. This built-in feature can be brought into use with simple wired electrical connections to the changeover system or via a local manual control mode.
MGO cooler units are available as a skid-mounted module or integrated as part of an Auramarine booster unit (AMB).
Extra cooling power with modular chillers
Auramarine modular chiller (AMC) units provide a complete solution for cooling fresh water in the MGO water-cooling circuit. They are required if there is not enough sufficiently cool LT-water or seawater available for the ACU or if the MDF fuel-type is such that it needs to be cooled to temperatures below 40°C to meet the standard 2cSt viscosity requirement or other engine-specific values that fall outside of these minimum requirements. Chiller modules use chilled water, comprising cooling water with 20 percent monoethylene glycol, for additional fuel cooling.
To ensure that the temperature change rate is maintained at a tolerable level, ACUs require a minimum of 150 litres of chilled water circulating in the system. If this is not available, Auramarine can provide a separate auxiliary tank.
The Auramarine chilling system is assembled from modular units and can therefore be customised to meet specific needs. As standard it consists of a compressor, condenser and evaporator, filters, a control panel and all necessary fittings and valves for installation and operation. If a set of two or more chilling modules are installed, the pipework and shut-off valves can be designed to meet customer-specific configurations. In such configurations, the units can also function independently. If necessary, excessive capacity can be shut off from the circuit.
Pump modules provide the necessary chilled water flow for cooler units in the closed chilled-water circuit. Chiller modules can be integrated into the same fuel system with Auramarine MGO coolers. Depending on layout arrangements on board, they can be skid-mounted or in a preferred separate location. Units are available in a 60kW to 300kW chilling power range.
|Cooling capacity (kW) 60 Hz||55||75||110||150|
|Cooling capacity (kW) 50 Hz||45||65||90||130|
|Available supply voltages (60 Hz)||200-230/360-400/440-480/575|