Exam Question
(a) Sketch and describe a central cooling fresh water system for a motor ship. (8)
(b) State the possible causes of corrosion in the closed system described in (a). (4)
(c) Explain how protections against corrosion is provided? (4)
Class 4 (4th Engineer)
MEKG
📅 Jun 2024
Reference Answer
### (a) Central Cooling Freshwater System
A central cooling system is a standardized design on modern motor ships to provide a stable, controlled, and non-corrosive cooling medium to all machinery. It utilizes a closed freshwater loop, which is in turn cooled by seawater in large central heat exchangers. The system is divided into two primary circuits: a High Temperature (HT) circuit and a Low Temperature (LT) circuit.
**1. System Components and Description:**
* **Central Coolers (Heat Exchangers):** Typically two large plate heat exchangers (PHEs). One is in operation while the other is on standby. Seawater acts as the primary cooling medium, flowing on one side of the plates, while the LT freshwater flows on the other side, transferring heat from the freshwater to the seawater.
A central cooling system is a standardized design on modern motor ships to provide a stable, controlled, and non-corrosive cooling medium to all machinery. It utilizes a closed freshwater loop, which is in turn cooled by seawater in large central heat exchangers. The system is divided into two primary circuits: a High Temperature (HT) circuit and a Low Temperature (LT) circuit.
**1. System Components and Description:**
* **Central Coolers (Heat Exchangers):** Typically two large plate heat exchangers (PHEs). One is in operation while the other is on standby. Seawater acts as the primary cooling medium, flowing on one side of the plates, while the LT freshwater flows on the other side, transferring heat from the freshwater to the seawater.
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