Sale of Evaporator Units for Boat
Is it time to replace the evaporator unit in your yacht's refrigerator or freezer? Or have you decided to assemble a refrigerator yourself and are looking for an evaporator of the required shape and size? In this section, we have selected models of the most common configurations and various sizes for your purposes.
If you need guidance on choosing the right evaporator, contact the experts at topRik for a free consultation – contact our team right now through the website’s online form or by phone (the number can be found on this page). You can also send your questions to the email address [email protected].
What is an Evaporator Unit and How It Works in a Refrigeration System
Yacht refrigerators and air conditioners do not create cold, but they do remove heat from one place and move it to another. This process is called cooling or refrigeration. Obtaining artificial cold for cooling food, other objects or the environment is achieved using special equipment.
On special vessels, for example, fishing boats, entire refrigeration rooms are equipped, where refrigeration is used to preserve cargo. Ship refrigerators and freezers for small fleets are designed to cool and/or freeze food and drinks to extend their shelf life.
Refrigerators that are designed for installation on yachts and other small fleet vessels are compression ones, like most household models.
Cooling systems typically include five components:
- compressor (pump);
- heat exchanger pipes outside the device, or condenser;
- expansion valve;
- heat exchanger pipes inside the box, or evaporator;
- refrigerant - the working substance of a refrigeration machine, which, when boiling, removes heat from the object being cooled and then, after compression, transfers it to the cooling medium due to condensation or another phase transition;
- a thermostat that controls the system itself.
Non-toxic freon (R-134a) is usually used as a refrigerant for yacht refrigerators and freezers.
Within this closed system, the refrigerant is converted from gas to liquid and back to gas, and as it changes state, it releases cold and absorbs heat. The process begins with a compressor creating pressure in the refrigerant.
The hot gas passes through a set of serpentine or spiral copper condenser tubes, where it condenses into liquid form and releases heat into the environment, aided by fans.
Flowing through a small opening called an expansion valve, the refrigerant turns back into a gas and absorbs heat as it changes state. Passing through another coil of copper or aluminum tubing inside the refrigerator compartment, the expanding chemical picks up heat from the large surface area of the evaporator, then the refrigerant becomes very cold. The vacuum from the compressor sucks the cold gas back in and the cycle repeats as long as the compressor is running. The inside of the refrigerator cools at a rate dependent on size, insulation efficiency, and ambient temperature.
All this operation of the system is called a duty cycle and usually lasts from 20 to 30 minutes of every hour.
But despite the general principle, yachts do not use household refrigerators, which we are used to seeing in the kitchen. The main difference between refrigerators for small fleets is their compactness and special fastening features to protect them from pitching on the water. Of course, you can simply purchase a car refrigerator and special mounts that allow you to install it on a boat or yacht, but it is better to take a marine one - it is safer and more practical.
Most often, built-in refrigerators are used on yachts. Firstly, they can be securely fastened, and secondly, they are easier to protect from water using protective panels. On non-built-in models, manufacturers install special sealed shields on electrical parts to protect them from moisture and magnetic seals on the door so that it does not open during motion.
On small yachts where space is limited, pull-out refrigerators can be an excellent solution. It's essentially a pull-out refrigerator drawer that runs on roller tracks that can be attached almost anywhere. A small lock on the handle prevents accidental opening of the refrigerator. As a rule, the volume of such refrigerators is limited to 30 liters, and the dimensions are 490x370x200 mm. If there is not enough space even for such a device, then there are models with a “remote” compressor. This structural element can be installed on the refrigerator on the right, left or at a distance, but not more than at a distance of 1.5 meters. As for premium yachts, large refrigerators are often used there, since the size of the vessel allows this.
In general, most refrigerators for yachts are of the compressor type, and stability of the entire system against pitching is achieved with the help of additional compressor fasteners.
So, the compressor and evaporator are the main characters in the cooling system of the most common compressor-type yacht refrigerator.
Modern manufacturers already offer thermoelectric cooling systems, without a compressor and freon. The operating principle of such a refrigerator is that direct current passes through a thermopile, consisting of two parts. At the point of their connection, heat is absorbed or released, depending on the direction of the current. Due to this, one part of the battery is cooled and the other is heated. The cold part of the battery is located inside the refrigerator and cools the food, and the hot part is outside, releasing excess heat. Thermoelectric refrigerators are almost silent, as they operate only on electricity. But, as you can see, they also operate on a similar principle of a compressor-evaporator pair.
The evaporator is a refrigerator unit in which the refrigerant (freon) is converted from a liquid state to a gaseous state, that is, evaporation. Under the pressure created by the compressor, the refrigerant in a liquid state enters the evaporator from the condenser. Through the evaporator, the refrigerant takes heat from the refrigerator compartment, helping to cool it, and transfers it to the condenser.
Types of Evaporators
The features of a ship's refrigeration system, as already mentioned, depend on its size and purpose. These parameters influence the choice of refrigeration unit configuration and, of course, the type of evaporators.
In mass-produced yachts and boats, depending on the location in the compression refrigerator, there are three main types of evaporators.
Open Evaporator
In small refrigerators and in older models, the open evaporator is what is usually called a freezer in everyday life. It may look like a sheet bent in an O- or C-shape. An open evaporator is the weak point of the refrigerator. Dents and scratches can lead to a violation of its seal and leakage of refrigerant, which means that you will have to replace the evaporator and refill the system with refrigerant, which will not be cheap. Therefore, when defrosting, you should never chip or scrape the ice or try to chip off frozen food.
Closed Self-Defrosting Evaporator
It is placed in the back wall of the refrigerator - filled with foam insulation and closed with the inner wall of the refrigerator compartment. The obvious advantages of this design are that the refrigerator is easier to clean, there is no need to defrost, and the evaporator is reliably protected from mechanical damage.
In refrigerators with the evaporator closed in the back wall, moisture settles on it, some of the condensate drops freeze, but no “fur coat” is formed, as is the case with an open evaporator. When the compressor is turned off, the frozen condensate thaws and flows down the wall of the refrigerator. In this design, the back wall is the coldest surface of the refrigerator compartment. Another evaporator is responsible for cooling the freezer compartment of such a refrigerator, which can also be completely closed, partially closed or open.
Evaporator Separated
The evaporator can be located behind the chamber wall or behind a partition. Such an evaporator is forcedly blown by a fan. Evaporators located outside the chamber are used in refrigerators with a No Frost system.
Classification Depending on Design
By design, evaporators are classified as:
- tubular;
- tubular-lamellar;
- tubular-wire;
- finned tubes;
- sheet-tube (sheet-rolling) etc.
The evaporators most often used in yacht refrigeration units are fin-tube and sheet-tube.
Sheet tube evaporators are more common because they are more convenient for storing food products. Finned-tube evaporators are installed in absorption refrigerators that do not have freezer compartments, in two-chamber refrigerators to cool a high-temperature chamber and when they have forced air circulation in the chambers using a fan.
Finned tube evaporators are designed in the form of a coil made of a steel pipe with horizontally located turns, between which a steel box with shelves for ice molds is placed. In compression refrigeration units, the finned tube evaporator is a coil of finned tube. For this purpose, an aluminum profile tube with longitudinal ribs or with mounted ribs made of thin aluminum plates is often used. Evaporators with thin plate fins are protected by a protective grille that protects hands from injury.
Sheet tube evaporators can be of three types, depending on how they are made:
- from a sheet with a pipe coil attached to it;
- from two welded steel sheets with channels stamped into them;
- from two aluminum sheets welded under pressure with subsequent expansion of the channels (rolling-welded method).
Evaporators made from a sheet with a coil attached to it are intended for freezers of two-chamber refrigerators. The aluminum sheet is shaped into a box of appropriate dimensions and a coil is fixed on its outer sides. In the end part of the coil, connected to the suction tube, a container is soldered in the form of a pipe of a larger diameter, designed to collect refrigerant vapor (steam collector, or reboiler).
Evaporators of any type are made of corrosion-resistant materials or anti-corrosion coatings are used to protect them, which do not have a harmful effect on food products. The modern level of production of aluminum evaporators ensures their anti-corrosion resistance and operational reliability, however, they must be handled carefully so as not to damage the protective coating and thin walls of the channels.
How to Choose an Evaporator Unit
Choice of evaporator unit may be needed:
- as a spare part to protect the crew during a long journey from the risk of being poisoned by stale food in the event of a refrigerator failure;
- to repair the yacht’s existing refrigerator or freezer;
- for a detail when building a refrigeration unit on a yacht with your own hands.
Regardless of the end goal, when purchasing an evaporator, you should focus on the parameters and other characteristics of an existing refrigerator or on the dimensions of the case in which you plan to assemble the unit yourself.
We are pleased to announce that in the topRik marketplace you can buy of evaporator units with various parameters and characteristics:
- in terms of dimensions - can be matched to almost any size refrigerator;
- by configuration - oval, flat, etc.;
- as a fully assembled unit with quick-release connections for easy installation;
- by the method of loading the unit - vertical and horizontal;
- by location - in chambers inside the unit or an external element;
- by purpose - universal, for a specific type of unit.
All models are already filled with environmentally friendly R134 gas and are supplied assembled with quick connectors and pipes of the appropriate diameter, length and shape.
Experienced sailors know that efficient cooling on yachts is vital. A sufficient amount of quality food and drinks is a guarantee of crew health. Therefore, the choice of refrigerators and their main elements (also as spare parts) should be approached seriously.