Heat exchangers are devices that facilitate the exchange

of heat between two fluids that are at different

temperature while keeping them from mixing with

each other.

Double Pipe Heat Exchangers

A typical double

pipe heat

exchanger

basically consists

of a tube or pipe

fixed

concentrically

inside a larger

pipe or tube

They are used when

flow rates of the

fluids and the heat

duty are small (less

than 5 kW)

These are simple to

construct, but may

require a lot of physical

space to achieve the

desired heat transfer

area.

Double-pipe exchangers is the generic term covering a range of

jacketed 'U' tube exchangers normally operating in countercurrent

flow of two types which is true double pipes and multitubular

hairpins.

One fluid flows through the smaller pipe while the other fluid flows through the annular space between the two pipes.

Two types of flow arrangement:

Parallel flow Counter flow

• The fluids may be separated by a plane wall but more commonly by a concentric tube (double pipe) arrangement shown in fig. If both the fluids move in the same direction, the arrangement is called a parallel flow type. In the counter flow arrangement the fluids move in parallel but opposite directions. In a double pipe heat exchanger, either the hot or cold fluid occupies the annular space and the other fluid moves through the inner pipe. The method of solving the problem using logarithmic mean temperature difference is typical and more iteration must be done. So it takes more time for the problem to solve. Therefore another method is practiced for solving this type of problems. This method is known as Effectiveness and Number of Transfer Units or simply ε-NTU method.“Effectiveness of heat exchangers is defined as actual heat transfer rate by maximum possible heat transfer rate”.The LMTD method may be applied to design problems for which the fluid flow rates and inlet temperatures, as well as a desired outlet temperature, are prescribed.

Application of Double Pipe Heat Exchanger

Pasteurization or sterilization

of food and bioproducts

Condensers and evaporators of

air conditioners

Radiators for internal combustion

engines

Charge air coolers and

intercoolers for cooling

supercharged engine

intake air of diesel

engines.

Compact Heat Exchanger

Apparatus that has two streams of fluid that exchange

temperatures in order to heat or cool the system.

Compact heat exchangers are a class of heat

exchangers that incorporate a large amount of heat

transfer surface area per unit volume.

Most automotive heat exchangers would come into the

compact heat exchanger category since space is an

extreme constraint for automotive applications.

• In the operation of machine tools it is necessary tocompensate the introduced heat in order to reduce thedeformation of the machine and thus minimize themanufacturing tolerances. Usually, the manufacturers of themachine tools demand a temperature tracking control of thesupply fluid with the ambient temperature. Therefore, oftenfluid-fluid cooling systems are used, which consist of two fluidcircuits.The primary circuit (I) is connected to the machinetool and the secondary circuit (II) to a coolant supply.Compact plate heat exchangers are often used as thermalcoupling of both circuits. Their advantages are a small overallsize, high overall heat transfer coefficients and low productioncosts.

• Compressed Gas / Water coolers

• Water / water coolers

• Oil / water coolers

• Preheaters, CiP-Preheaters

• Condensers and evaporators for chemical and

technical processes of all kinds.

• Machine coolers

• Oil coolers for hydraulic systems

• Oil and water coolers for power machines

• Refrigeration and air-conditioning units

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Shell and Tube Heat

Exchanger

Shell and tube type heat exchangers (multi-tubular heat

exchangers) feature a shell (body) and multiple tubes (heat

transfer tubes).

They are designed so as to achieve a large transfer surface area

within a small space, with minimal loss of fluid pressure.

They can be applied to all purposes, from low temperature to high

temperature, from low pressure to high pressure, and for heating,

cooling, evaporation and condensation.

They are highly reliable in comparison with other types of heat

exchanger, and are the most widely used in the hydraulic and

chemical related industries.

Their basic structure is simple, so maintenance is very easy.

• It has a series of tubes which is enclosed by

a shell. One fluid flows inside the tubes

while the other liquid flows over the outside

walls of the tubes which, basically, is the

shell. It's highly recommended for places

where there's a need for high heat transfer

coefficient as the number of tubes can be

increased depending on the need. Due to its

unique shape, it finds use in high pressure

applications.

Rolling machines

forming machinery

machine tools

construction equipment

chemical plants

shipping

Power generation

Steamsuperheaters and condensers

Food processing machinery

Medical appliances

Semiconductor machinery equipment

Co-generation

Plate and Frame Heat

Exchanger

A plate heat exchanger is a type of heat exchanger that uses metal plates

to transfer heat between two fluids. This has a major advantage over a

conventional heat exchanger in that the fluids are exposed to a much

larger surface area because the fluids spread out over the plates. This

facilitates the transfer of heat, and greatly increases the speed of

the temperature change. Plate heat exchangers are now common and very

smallbrazed versions are used in the hot-water sections of millions

of combination boilers. The high heat transfer efficiency for such a small

physical size has increased the domestic hot water (DHW) flowrate of

combination boilers.

• The small plate heat exchanger has made a great impact in domestic heating and hot-water. Larger commercial versions use gaskets between the plates, whereas smaller versions tend to be brazed.

• The concept behind a heat exchanger is the use of pipes or other containment vessels to heat or cool one fluid by transferring heat between it and another fluid. In most cases, the exchanger consists of a coiled pipe containing one fluid that passes through a chamber containing another fluid. The walls of the pipe are usually made of metal, or another substance with a high thermal conductivity, to facilitate the interchange, whereas the outer casing of the larger chamber is made of a plastic or coated with thermal insulation, to discourage heat from escaping from the exchanger.

• It consists of a series of gasketed, embossedmetal plates arranged alternately and boltedtogether between end frames to formchannels through which hot and cold mediaflow. The hot fluid flows on one side of theplate while the cold fluid flows on the other,with the plate itself providing the mosteffective means to transfer heat from onefluid to the other. Gaskets on the plates sealthe channels and provide flow direction.

As liquids flow counter-currently through thechannels between the plates, the cold liquidbecomes warmer and the hot liquid cooler.Most units are designed for a one-pass/one-pass flow arrangement, resulting in allnozzles being installed on the stationary endframe, which facilitates simpler pipingarrangements and easier disassembly.

• For close temperature control of fluids for heat

recovery applications particularly in operations

requiring frequent opening and cleaning of the unit.

• Especially effective in high volume applications and/or

where both media require the use of costly resistant

metals such as titanium, palladium or various other

alloys.

Energy> Solar collector fluid isolation> Heat recovery in co-generation facilities> Turbine cooling in power plants> Geothermal water isolation> Isolation and “free cooling” in HVAC> Heat recovery from boiler blowdown> District chilled water coolers

Pulp & Paper> Heat recovery from de-inking effluent> Jacket water cooling in black liquor recovery process> Heating white water in paper mills> Cooling bleach solutions

Integrated Systems> Welder water coolers> Cooling machine oil> Cooling grinder coolant> Cooling electronic equipment> Hydraulic oil coolers

Chemicals> Waste heat recovery from condenser water> Heating or cooling jacket fluid for chemical reactors> Heating and cooling chemical solutions

Metals

> Heating phosphatizing solutions

> Acid coolers

> Cooling ammonia liquor at coke plants

> Cooling anodizing solutions

> Heating of electrolyte solution in copper

mills

> Cooling quench oil

> Heating and cooling plating solutions

Maritime

> Lube oil cooling

> Cooling engine jacket water

> Heating ship service water

Food & Beverage

> Heating wash water

> Heating and cooling sugar solutions

> Ethanol distillation

Oil & Gas

> Heat recovery from lean to rich amine

solutions

Miscellaneous Manufacturing

> Preheat make-up water in photo

processing

> Paint coolers

> Heating and cooling kaolin slurries.

Regenerative Heat

Exchanger

• A regenerative heat exchanger, or more commonly a

regenerator, is a type of heat

exchanger where heat from the hot fluid is

intermittently stored in a thermal storage medium

before it is transferred to the cold fluid.

• They have 2 types of regenerative heat exchanger,

which is static and dynamic heat exchanger.

Static Heat Exchanger

Basically a porous mass that has a large heat storage

capacity, such as ceramic wire mesh.

Hot and cold fluids flow through this porous mass

alternatively.

Heat is transferred from the hot fluid to the matrix of

the regenarator during the flow of the hot fluid., and from

the matrix to the cold fluid during the flow of the cold

fluid.

Thus, the matrix serves as a temporary heat storage

medium.

Dynamic Heat Exchanger

Involves a rotating drum and and continuos flow of the hot

and cold fluid through different portions of the drum so that

any portion of the drum passes periodically through the hot

stream, storing heat, and then through the cold stream,

rejecting this stored heat.

Again the drum serves as the medium to transport the heat

from the hot to the cold fluid stream.

Application of Regenerative Heat Exchanger

Liquid fluid

Pharmaceutical processing

Air-conditioning

Cooling towers

Air-preheaters

https://www.google.com.my/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0CAcQjRw&url=http%3A%2F%2Fwww.slideshare.net%2Facpammar%2Fheat-exchangers35430932&ei=bMfqVPfxFtXq8AWrhYLoAw&psig=AFQjCNF48axyNUOYFb3TLdvE515EOG2NBg&ust=1424758718671896

http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2621.2004.tb09927.x/abstract

https://books.google.com.my/books?id=ZsU5A1mANWUC&pg=PA2&lpg=PA2&dq=application+of+double+pipe+heat+exchanger&source=bl&ots=sa5CBGKVCa&sig=LNwOwbIAdldy0HlBHMgiul_PltY&hl=en&sa=X&ei=tdXqVMzTF8SA8gWiuYKgAg&ved=0CN0BEOgBMBs#v=onepage&q=application%20of%20double%20pipe%20heat%20exchanger&f=false

http://narsa.org/wpcontent/uploads/2012/09/NARSA_CompactHXDesign_Sep2012-Borghese.pdf

http://enggyd.blogspot.com/2011/04/double-pipe-heat-exchanger-experiment.html

http://www.kamui.co.jp/english/products/shell_and_tube/

http://www.brighthubengineering.com/hvac/61791-features-and-characteristics-of-the-flat-plate-heat-exchanger/

http://inproheat.com/product/heat-exchangers/plate-and-frame

http://www.harshindia.com/Tranter_Plate_and_Frame.html

http://en.wikipedia.org/wiki/Regenerative_heat_exchanger