Pool Heater Heat Exchanger: Shell vs Plate Designs

The role of the heat exchanger in a pool heater

The heat exchanger is the component inside a pool heater that moves heat from the heating side to the pool water without letting the two fluids mix. In a gas heater, the heating side is burned gas. In a heat pump, the heating side is hot refrigerant. In a solar heater, the heating side is water warmed by the sun. The pool water always flows on its own side of the exchanger.

Pool heater listings describe the exchanger with two separate kinds of words: the design, meaning how the heat-transfer surfaces are arranged, and the material, meaning what those surfaces are made of. This article explains the two design names you will see in listings, shell-and-tube and plate, and how to read them in a title.

Shell-and-tube heat exchanger

A shell-and-tube exchanger is a bundle of small tubes inside a larger outer shell. The heating source flows through the shell and around the outside of the tubes, while the pool water flows through the tubes, or the reverse. This shape is the type of exchanger described in most gas pool heater listings: burned gas passes along the tubes and heats the water inside them.

In a listing, the design may be named directly as "shell and tube" or the title may state only the material, such as "copper heat exchanger" or "cupronickel heat exchanger". When a gas heater listing names a material without a design word, the shell-and-tube shape is the one the maker is describing.

Plate heat exchanger

A plate exchanger is a stack of thin metal plates pressed together, with narrow channels between them. Pool water flows through one set of channels and the heating source flows through the alternating set. This shape is the type described in most heat pump listings, where the refrigerant side needs a compact surface to pass heat to the water.

Plate exchangers appear in titles under words like "plate heat exchanger" or simply "titanium heat exchanger" when the design is assumed. The material word and the heater type together tell you which shape to expect before you open the spec sheet.

How the design appears in a listing

The quickest clue in a title is the heater type. Gas heater listings pair the fuel word (natural gas or propane) with an exchanger material. Heat pump listings pair the compressor and refrigerant words with an exchanger material. The design word itself is optional in both.

Makers such as Raypak and Pentair name the heater type and the fuel in the title, and leave the exchanger design to the manual. Reading those maker pages is how you confirm the shape. The listing title itself is rarely the source of the design word.

When the design word is missing, read the maker's spec sheet or manual. Makers publish the exchanger design under "specifications" or "components". The maker's page is the place to confirm what a listing abbreviates. For a gas heater, a licensed gas installer and the maker's manual decide the gas supply and installation; this article only explains listing words.

Design words versus material words

Design and material are separate questions. Design names the shape: shell-and-tube or plate. Material names the metal: titanium, copper, cupronickel or stainless steel. A listing may state one, both, or neither. The separate articles on this site cover exchanger material and titanium versus copper in more detail.

The material word matters for the pool's water, but this site does not advise on water chemistry. Read material words as listing terms, ask the maker which material the exchanger uses, and check what the warranty covers for that part.

What this article does not cover

This article and the buying guides on this site compare stated details only. The guides do not measure heat transfer, operating efficiency, heating time, noise, or how long an exchanger part will last. A design name is a geometry, not a performance rating.

The right heater for your pool depends on the heater type, the fuel supply, whether the pool is inground or above ground, and the output figure the maker recommends. Use the maker's sizing page and ask an installer which heater matches your equipment pad. See the natural gas heater guide, the pool heat pump guide, the inground heater guide and the above ground heater guide for the buying options.

Questions to ask the maker

Before you settle on a heater, use these questions to turn a short listing into the full picture of the exchanger.

• Does the listing name the exchanger design, or only the material?
• Is the exchanger material titanium, copper, cupronickel or stainless steel?
• Which exchanger shape does the maker use in this model line?
• What does the warranty cover for the exchanger part?
• Does the maker publish a sizing page that matches an output figure to your pool?
• Which heater type fits your pool: gas, propane or a heat pump?

What to pick for your situation

Questions

Do pool heater listings state "shell and tube" or "plate"?

Rarely by name. Most titles state the heater type (gas, heat pump) and the exchanger material (copper, titanium, cupronickel). The design is usually in the spec sheet or manual. The heater type is the main clue: shell-and-tube in gas heaters, plate in heat pumps.

Which heat exchanger design do gas pool heaters use?

The shell-and-tube shape is the type described in most gas heater listings. The burned gas flows around a tube bundle while pool water flows through tubes. Read the material word and confirm the design on the maker's page.

Which design do heat pumps use?

Plate exchangers are the shape described in most heat pump listings. Thin plates create alternating channels for refrigerant and pool water. Look for "plate" or the material word, then check the manual.

Is titanium a design?

No. Titanium is a material word. It can be used in either a shell-and-tube or a plate exchanger. Keep design and material separate when reading a listing.

Does the exchanger design decide which heater to buy?

No. Pool type, fuel supply (natural gas, propane or electricity) and the maker's recommended output figure decide the heater. The exchanger design is a part description, not a shopping category.

Where is the exchanger design stated?

Makers publish it in the manual or spec sheet, not always in the listing title. Check the maker's product page and the manual for the section on components. That is where the design word appears.