Structural differences and features between chillers with built-in water tanks and chillers without water tanks

1. There are two types of chillers: those with built-in water tanks and those without water tanks.

Chillers are classified into two types: "built-in water tank type" and "tankless type." Built-in water tank type chillers are also called "closed circuit chillers," while tankless type chillers are called "open circuit chillers."

The water tank here refers to a tank that stores the cooling water circulated by the chiller.

Closed-circuit chillers have an internal cooling water tank, so they do not require any special external piping equipment and can be installed in small spaces. Cooling is achieved by connecting the chiller directly to the heat source equipment.

On the other hand, open circuit chillers draw in cooling water from outside, so an external water tank and piping equipment are required, necessitating a large amount of space.However, they have the advantage of being able to directly cool an open water tank, which is not possible with built-in water tank chillers, and can be low cost if you purchase a new chiller while utilizing existing equipment.

It is important to choose the type that is best suited to your site based on the characteristics of each, so let's take a closer look at these in the next chapter.

2. Features of chillers with built-in water tanks

First, we will introduce the structure and features of chillers with built-in water tanks.

■ Features of chillers with built-in water tanks

Chillers with built-in water tanks have a built-in water tank containing the liquid that will be used as cooling water refrigeration circuit, and a pressure pump, and their greatest advantage is their convenience, as they do not require a separate water tank or the associated piping.They are also called closed circuit, sealed circuit, or built-in tank types.

The discharge side of the tank is equipped with a pressure pump, which provides sufficient discharge power, but the inlet side does not have power, so in order to flow the same amount of cooling water into the tank as the discharge volume, the load side (the side of the object to be cooled) must be a closed circuit.

Also, keep in mind the disadvantages of not being able to expand the tank and not being able to connect it directly to an open aquarium.

When using a built-in chiller to regulate the temperature of a liquid in an open tank, the liquid is cooled indirectly using a heat exchanger as shown in the diagram below.

■ Advantages and disadvantages of chillers with built-in water tanks

The advantages and disadvantages of chillers with built-in water tanks can be summarized as follows. Consider introducing one that suits the characteristics and conditions of your own factory.

<Advantages of chillers with built-in water tank>

• ・Installation is possible by simply connecting the piping to the chiller body.
• No need to prepare a separate water tank
• ・Can be installed in a space-saving manner

<Disadvantages of chillers with built-in water tank>

• You can't change the size of the tank
• ・Maintenance is difficult
• ・Cannot be connected directly to an open aquarium

3. Features of tankless chillers

Next, let's take a look at the structure and features of a tankless chiller.

■ Features of water tank-less chillers

As the name suggests, tankless chillers do not have an internal tank, but instead use a circulation pump to draw in liquid from an external tank and cool it in refrigeration circuit. They are also called open circuit chillers.

Tankless chillers require a water tank and pump outside the chiller, which requires the design of the associated system and piping. Because installing a new water tank is time-consuming and costly, they are generally used to cool existing water tanks.

However, having the equipment outside also means that it is easy to expand the tank, replace the chiller, and perform piping maintenance.

If you anticipate changing your water tank or equipment in the future, choosing a chiller without a water tank is one option. When replacing your water tank, be sure to note that there are regulations regarding tank capacity depending on the chiller model.

Also, since the main unit is compact, if you already have an aquarium, the installation space will be smaller than that of a built-in type.

■ Advantages and disadvantages of tankless chillers

In addition to the above, tankless chillers have the following advantages and disadvantages. It's important to compare them with built-in tank chillers to determine which is best for you.

<Advantages of a water tank-less chiller>

• - Can be connected directly to an open aquarium
• - Existing aquariums can be used
• ・The tank, piping, and system are open, making maintenance and replacement easy.
• ・The chiller body is compact

<Disadvantages of tankless chillers>

• ・Aquariums, pumps, and associated systems and piping are required separately.
• ・For new installations, space is required for the installation of the water tank and piping.
• ・Water tank capacity is regulated depending on the chiller model.