Resources> Heat Exchanger Basics
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What is a Heat Exchanger?
A Heat Exchanger is a device built for the efficient transfer of heat from one medium to another, whether the media are separated from each other, so they do not mix, or the media are in direct contact.
Where are Heat Exchangers used?
Heat Exchangers are widely used in space heating, water heating, refrigeration, air conditioning, power plants, chemical plants, petrochemical plants, sugar refineries, petroleum refineries, natural gas processing, industrial machinery and even motorized vehicles.
What is a Brazed Plate Heat Exchanger?
A Brazed Plate Heat Exchanger is a type of heat exchanger that because
of its design, allows for a very compact-sized unit with the
ultra-efficient transfer of heat from one fluid to another fluid,
without the two fluids mixing. The design of Brazed Plate Heat
Exchangers calls for the use of thin layers of stamped stainless steel
plates. The stamping pattern of the stainless steel plates creates
baffles which become channels for two separate fluids to run through,
typically in a counter-current flow direction, in that a counter-current
flow results in more heat transfer between the fluids in a smaller area.
Our line of Brazed Plate Heat Exchangers, called our
VAU Blockbuster,
are manufactured to the highest quality standards in our facility in
Munich, Germany.
What is brazing?
Brazing is a joining process whereby a filler metal or alloy is heated to melting temperature and distributed between two or more close-fitting parts by capillary action. At its liquid temperature, the molten filler metal and flux interacts with a thin layer of the base metal, cooling to form a strong, sealed joint. By definition the melting temperature of the braze alloy is lower (sometimes substantially) than the melting temperature of the materials being joined. In the case of a Brazed Plate Heat Exchanger, the brazing material is usually copper or a nickel-copper alloy. The choice of brazing material is dependent upon the fluids that will ultimately flow through the heat exchanger and be in contact with the brazing material. Certain fluids are not compatible with certain metal alloys. For example, ammonia is highly corrosive to copper.
Where are Brazed Plate Heat Exchangers used?
Because of their compact size, high performance relative to their size, and reasonable cost relative to other types of heat exchangers, brazed plate heat exchangers are used in as many heat transfer applications as possible. Some of the limitations of brazed plate heat exchangers include 1) their inability to be taken apart for periodic cleaning, which can become necessary depending upon the specific fluids being used with the heat exchanger; 2) the amount of pressure driving fluids through a brazed plate heat exchanger usually must be less than 450 psi; 3) the maximum operating temperature of a brazed plate heat exchanger is usually about 383 deg. F, so the fluids flowing through the brazed plate heat exchanger must typically average no more than this maximum; and, 4) the fluids being used with a brazed plate heat exchanger must be compatible with the brazing material...certain fluids, like ammonia, are highly corrosive to copper, which is a common brazing material.
Even with these limitations, the number of heat transfer applications suitable for Brazed Plate Heat Exchangers is numerous.
Brazed Plate Heat Exchangers have made their way into the green movement. Heat Exchangers, by definition, reclaim energy (heat), which make their use desirable and more efficient in all applications. Green projects that include heat exchangers fall into the category of hydronics applications. Hydronics is defined as the use of water as a heat-transfer medium in heating and cooling systems.
Examples of hydronics applications with which Brazed Plate Heat Exchangers are a component include solar potable and non-potable water heating, swimming pool/spa heating, radiant floor heating, snow melt, and chilled beams. Another very popular application in northern climates is with outdoor wood-fired boilers, which are used to heat water with wood in a separate, free-standing shack or shed, near a house, and then this hot water is piped, underground, into the house, where it is used to heat the house and domestic (drinking) water.
Brazed Plate Heat Exchangers are also used in industrial machinery applications for compressor and hydraulic oil cooling, refrigeration applications, and even conversions of diesel vehicles to bio-diesel and straight vegetable oil fuels for preheating.
Which size of Brazed Plate Heat Exchanger is right for my application?
Calculating the size of a brazed plate heat exchanger necessary for a particular application and system is much more complicated than the scope of this basic introduction to heat exchangers.
Correctly sizing a Brazed Plate Heat Exchanger for a particular application and system is vital, though, to the performance of the whole system and requires the following information:
1) the heat load, or performance, usually stated in BTU/hr, tons, or kW; 2) the fluids being used in the system;
2) the temperatures of the fluids being used in the system;
3) the flow rate of the fluids being used in the system, usually stated in gallons per minute, liters per minute, or lbs per minute; and,
4) the allowable pressure drop of the fluids running through the heat exchanger.
If I provide you with the information specified above, can you calculate which Brazed Plate Heat Exchanger is right for my application and system?
Yes. Please either click here for our online sizing calculation form, which you can complete online and automatically submit to us or click here for a pdf version of our sizing calculation form that you can print and fax to us at +1.928.441.2093.
Once we receive your request, we can quickly calculate your requirements and assist you in the selection of the appropriately sized VAU Blockbuster Brazed Plate Heat Exchanger.