HWL – Hot water loop

Polger Authorized Alfa Laval Distributor
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HWL – Hot water loop polgernowy 2026-08-26

HWL - Hot water loop

The Alfa Laval Hot Water Loop is a steam-heated system engineered to deliver efficient and reliable heating for freshwater generation, diesel engine preheating or other applications. On vessels where jacket water temperature is inconsistent or insufficient, the HWL ensures a stable hot water supply. This consistency optimizes the performance of systems such as the Alfa Laval AQUA Blue and AQUA Blue E2 freshwater generators.
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Key advantages of the HWL hot water loop system
  • Energy efficiency – Low electrical power consumption (0.5–12 kW) enabled by bypass piping on the hot water pump and an IE3 motor.
  • Modular design – Three configurable scopes of supply allow flexible installation, reduced footprint, and potential CAPEX savings.
  • Optimized freshwater generation – Automatic temperature control ensures stable operation and maximizes uptime.
  • Reduced engine start-up time – efficient pre-heating eliminates manual adjustments, shortening diesel engine start-up and improving vessel readiness.
Features that ensure a steady flow of hot water

Bypass piping before the hot water pump maintains continuous flow when the HWL is not in operation, ensuring system stability.

Isolated media circuits enable the use of both jacket water and steam, offering flexible integration with existing energy sources.
Modular system design supports three scopes of supply, allowing easy adaptation to different vessel layouts and reducing installation complexity.
Automatic operation maintains a constant temperature without manual adjustment, improve fresh water production and reduce operator workload.

Full-flow braced heat exchanger ensures efficient heat transfer and fast system start-up.

IE3 electric motor on the hot water pump delivers reliable performance with low power consumption.

How it works

The Alfa Laval HWL – Hot Water Loop uses steam to heat water within the loop. A steam control valve regulates the steam flow based on the set point from the temperature controller mounted on the hot water outlet line. A dedicated hot water pump ensures constant circulation through the HWL braced heat exchanger, enabling recirculation when the engine is at low load or stopped. This pump must be running when the system is used for engine preheating. A blinded flange connection allows flexible integration with various heating or preheating applications.
Features that ensure a steady flow of hot water
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HWL – Hot water loop shown with options heat exchanger system incl. pump and by-pass valve.
A. Hot water inlet, B. Hot water outlet, C. Steam inlet, D. Condensate outlet , E. Pre-heating connection

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Polger Authorized Alfa Laval Distributor

Polger is an authorized distributor of Alfa Laval equipment and systems for the marine industry. We provide reliable solutions for fuel and oil handling, water treatment, heat transfer and onboard installations.

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Contact Polger to select the right Alfa Laval solution for your vessel or marine installation.

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