Whether coastal cruising or crossing oceans, enjoying the comforts of home while aboard requires hot water. Marine Calorifiers provide an efficient and reliable way to produce ample and potable hot water for galley, shower, and cleaning needs when out on the waves. From small sailboats to massive cruise ships, marine calorifiers deliver vital hot water while taking up minimal space and energy. They guarantee the ultimate performance even in demanding marine environments.
Marine Calorifiers come in a range of sizes, heating methods, and configurations. Choosing the right unit to meet the hot water demands and constraints of your vehicle requires careful consideration. They are also often also called ‘boat cylinders’ or ‘boat water heaters’.
While they have the same purpose as a hot water cylinder, the term “calorifiers” is more commonly used when describing hot water cylinders installed in large industrial, or in this case, marine applications.
Marine Calorifiers are one of many types of water heaters that Newark Cylinders manufactures.
What is a Marine Calorifier?
A Marine Calorifier is a simple and efficient means of storing heating water in your boat’s domestic hot water system, so it is available at a point-of-use such as showers, taps and the galley (kitchen area).
How is water heated in a Marine Calorifier?
A marine calorifier can be heated directly or indirectly.
The direct method of heating water in a calorifier is through a built-in immersion heater. In this case, the boat’s electricity source (or possibly through Solar PV panels) is used to heat the water up.
An indirect method is to provide heated water via a heat exchanger coil. This heat would usually be generated by an external heat source such as the boat’s engine.
Additionally, there is the option to include twin coils. This allows you to utilise the heat generated by two separate heat sources.
Factors to consider when choosing a standard or designing a bespoke Marine Calorifier:
- Required water supply – Consider the size of the calorifier based on estimated water usage for showering, cooking, etc.
- Available power sources – Compatible with electric, engine heat exchange, or a combination of these. Other heat sources may include solar, wood burners, boilers, and heat pumps.
- Desired recovery time – Faster recovery requires more heating power. If you choose a bespoke design, the option of a larger coil is available, and will potentially increase the recovery time.
- Physical size limitations – Consider space constraints where the unit will be installed. It is also advised to install the calorifier as close to the engine as possible to reduce heat loss from the flow and return pipework.
- Construction material – Copper is recommended for corrosion resistance in marine environments.
- Cost and budget – The purchase price alongside installation and maintenance costs should be considered. Direct models are often cheaper in both cases, as they don’t feature any coils. Standard models are usually more cost-effective than bespoke manufactured ones, as they are mass-produced.
- Safety features – All calorifiers should feature a pressure relief valve. Any immersion heater(s) fitted should have a built-in high-limit thermostat, which would protect the cylinder in the event that the control stat ever fails.
- Ease of maintenance -Having accessible connections, in particular the drain valve, is important for maintaining your calorifier. Having plenty of clearance for replacing the immersion heaters is also important.
FAQs
A calorifier is a type of hot water storage vessel that heats water indirectly using an external heat source. Unlike a standard hot water cylinder that may use a direct immersion heater, a calorifier relies on a heat exchanger coil through which hot water or steam from a boiler, engine, or other heat source is circulated. The heat transfers through the coil wall into the stored water without the two supplies ever mixing.
Calorifiers are widely used in marine, commercial, and industrial applications where reliable hot water storage is needed from an existing heat source.
A calorifier heats and stores domestic hot water so it is available on demand at taps, showers, and other outlets. It works by drawing heat from a primary source (such as a boiler, engine cooling system, or heat pump) and transferring it to a separate body of stored water via an internal coil.
This means the water you use for washing and cleaning is heated efficiently without requiring its own dedicated burner or heating element, though many calorifiers also include an immersion heater as a backup or secondary heat source.
Hot water or steam from the primary heat source is circulated through a coil fitted inside the calorifier.
As the hot fluid passes through the coil, heat transfers through the coil wall and into the surrounding stored water. The primary fluid and the stored domestic water never come into contact with each other, keeping the two circuits completely separate.
Once the stored water reaches the desired temperature, it is available at mains pressure or system pressure, depending on the installation.
When hot water is drawn off, cold water enters the vessel to replace it, and the heating cycle continues as long as the primary heat source is active.
Installing a calorifier unit is relatively straightforward if your boat has a pressurised water system and space near the engine.
It can be heated via the engine or shore power immersion heater. Read more here
If you are interested in purchasing a bespoke Marine Calorifer, get in touch with us.
