Refrigerant heat exchanger - characteristics, principles of operation, structure
The freon heat exchanger, also known as a refrigerant to water heat exchanger, is commonly used in refrigeration, air conditioning, and heating processes in heat pumps etc. It is a device with a relatively narrow range of applications due to the handled media. If you want to learn what a freon heat exchanger is and where it is used, be sure to read the article below. By reading this blog post, you will also learn how the freon heat exchanger works, how it is constructed, and in which industries and for what purposes it is used. Welcome to read.
What is a Freon Heat Exchanger?
✅ The freon heat exchanger is a brazed plate heat exchanger with a special design enabling it to work with two media in different states of matter. A freon heat exchanger is a device used for heat transfer between two fluids with different states of matter. One of the fluids is a liquid, such as water or water with glycol, and the other is a gas, such as freon, R404, R32, R290, or similar.
The freon heat exchanger is used in various refrigeration and air conditioning systems where effective heat transfer is necessary.
Evaporator, or Refrigerant Heat Exchanger in Practice
The refrigerant heat exchanger is used as an evaporator in refrigeration units, heat pumps, and air conditioners, always considering the maximum working pressure that may occur in such an installation - due to the fact that each heat exchanger has a maximum allowable working pressure.
Refrigeration evaporators or heat pump evaporators are key components in terms of the operation of each of the above devices. These are devices responsible for heat exchange between different media. In the evaporator, heat from the surroundings is transferred to the refrigerant medium. As a result of heat input, the refrigerant (e.g., freon) changes its state from liquid to gas. This process is commonly known as evaporation.
Condenser, or the Second Application of the Freon Heat Exchanger
✅ The freon heat exchanger is also used as a condenser, which is the second crucial device in terms of heat exchange in heat pumps, air conditioners, and refrigeration units.
A refrigeration condenser or heat pump condenser is a fundamental element in the refrigeration cycle of the aforementioned devices. Its task is to transform the gaseous refrigerant medium (e.g., freon) into a liquid state. This process occurs after the gaseous refrigerant has been previously evaporated and has absorbed heat in the evaporator.
✅ Refrigerant heat exchangers have quite often characteristic connections, pipes for brazzing (for gas media) - whereas the 2nd channel is traditionally threaded (destinated for water). But the most important feature is the resistance for high pressure generated by refrigerants.
How Does the Refrigerant Plate Heat Exchanger Work?
The refrigerant plate heat exchanger is a device that allows heat exchange between two substances: gas - e.g., freon, and liquid, e.g., glycol or a water-glycol mixture. This is possible thanks to the application of a special design consisting of plates through which both media flow without mixing (which is crucial). Thus, the refrigerant plate heat exchanger provides efficient and rapid heat exchange between two media - also in different states of matter.
✅ It is worth noting that the construction of the freon plate heat exchanger is adapted to handle gases under high pressure, up to 4.5 MPa (or 45 bar). This is the basic determinant that allows for the use of exchangers with gas media as well, as these media tend to operate at high pressures.
❌ If the heat exchanger is not certified for at least 40-45 bar - it shouldn't be used as a unit for refrigerant, freon or similar gas.
Construction of the Freon Heat Exchanger
Freon Heat Exchangers consist of a series of plates that are brazed together, like a typical plate heat exchanger. The plates have special channels through which fluids flow, enabling rapid and effective heat exchange. The exchanger is made of high-quality materials that are resistant to corrosion and ensure long-lasting durability of the device (316L stainless steel vacuum-brazed with copper). The connection to the gas medium has a slightly smaller diameter than the connection to the liquid medium.
Thanks to its construction and properties, this type of exchanger is widely used in various industries, such as the chemical industry, energy sector, or food industry.
✅ The difference is production process, especially brazzing - as refrigerant to water heat exchanger requires being more solid and resistant for pressures.
Where is the Refrigetant to Water Heat Exchanger Used?
The refrigerant to water heat exchanger is used in many different branches of industry. It is often used in air conditioners and refrigerators, where it serves as a condenser. Additionally, freon heat exchangers are also used in refrigeration devices such as coolers, freezers, and display cases to maintain the proper temperature and prevent food spoilage. Besides the refrigeration sector, refrigerant heat exchangers can also be found in the chemical, pharmaceutical, and industrial processes where efficient cooling or heating of substances is required to maintain stable production conditions.
Refrigerant to water heat exchangers are used in the following devices:
- ✅ heat pumps (in this case, the freon heat exchanger can function as a heat pump evaporator and heat pump condenser),
- ✅ air conditioners (in the ventilation and air conditioning industry, the freon heat exchanger is successfully used as an air conditioner evaporator and air conditioner condenser),
- refrigeration units (in turn, in the refrigeration industry, the freon heat exchanger is used as a refrigeration evaporator and refrigeration condenser).
What Refrigerants Do Freon Heat Exchangers Work With?
✅ Plate freon heat exchangers work with the following refrigerants:
- R32 - difluoromethane. This refrigerant is used in air conditioning systems, heat pumps, and refrigeration - for example, in food transportation (refrigerated trucks).
- R404A - it is a mixture of difluoromethane, pentafluoroethane, and hexafluoropropene. This refrigerant is used in industrial refrigeration.
- R407C - it is a mixture of difluoromethane, pentafluoroethane, and octafluoropropane. It is used in air conditioning and refrigeration.
- R410A - it is a mixture of difluoromethane and pentafluoroethane. Currently one of the most popular refrigerants. It is used in air conditioning systems and heat pumps.
- R290 - similar to the above, completely safe, gaining popularity in recent years refrigerant.
- many other refrigerants, which tend to be similar
Refrigerant to water heat exchangers are designed to efficiently exchange heat between the refrigerant and the medium to be cooled. The gases mentioned above are used due to their good thermodynamic properties and chemical stability. Through cooperation with these refrigerants, plate freon heat exchangers are effective and reliable in air conditioning, heat pumps, industrial cooling, or ice production.
What Sets Refrigerant Heat Exchangers Apart from Traditional Plate Heat Exchangers?
✅ Refrigerant heat exchangers differ from traditional liquid-liquid plate heat exchangers in their design that allows handling gases. These differences include the presence of connections for gas media and a construction that guarantees the exchanger's resistance to high pressures, reaching up to 45 bar (4.5 MPa). For comparison, plate heat exchangers designed to handle liquids typically have certification for only 20-30 bar.
Using a traditional plate exchanger instead of a freon exchanger for a heat pump
✅ Some people are convinced that it is possible to design an installation with refrigerants such as R32, R404, R407, R410, R290, or similar - ensuring that the pressure parameters of around 25-30 bar will not be exceeded. This would mean the possibility of using a standard - cheaper liquid-liquid heat exchanger, certified for 30 bar. However, ❌ these are rather hasty and risky actions, as we will try to demonstrate:
- ❎ The variability of pressures with gas media is essentially uncontrolled, and such media tend to experience sudden pressure fluctuations depending on temperature changes, which traditional heat exchangers are usually not prepared for (risk of leakage).
- ❎ Moreover, such media quickly reach much higher pressures with increasing temperatures. In some systems, pressure may exceed 25-30 bar already at 30-35 degrees Celsius. This would force us to operate our domestic heat pump (whether professional or from a refrigeration unit - it doesn't matter) only at extremely low temperatures, which would clearly render it non-functional.
- ❎ The last aspect is the warranty coverage by heat exchanger manufacturers. In most cases, simply using the heat exchanger with a maximum working pressure of 30 bar - with gas media or refrigerant - may result in warranty voidance as improper use. Explaining that our system did not exceed pressures higher than 30 bar - is essentially pointless, as any expert will say that the indicated media tend to operate at significantly higher pressures and, in essence, using them inherently means we won't be able to prove that our system did not exceed the specified parameters. Traces of soldering or welding on the connections - will usually be obvious evidence for the use of gas media. Therefore, it is worth considering whether it is worth risking when creating your own heat pump - probably the better solution will always be to purchase a professional heat exchanger for refrigerant.