2017년 4월 10일 월요일

Commissioning and Installation of Heat exchanger

Commissioning and Installation of Heat exchanger



Commissioning and Installation


1. How to install a Heat Exchanger

The correct method of heat exchanger installation varies depending upon the exact type of unit and the environment of operation. For installations instructions please refer to one of our Installation and Operation Manuals
  • Shell and Tube Heat Exchangers – IOM
  • Brazed Plate Heat Exchangers – IOM


2. How to increase the lifetime of a Heat Exchanger

Heat exchangers are manufactured from robust materials, have no moving parts and operate at a variety of different pressures and temperatures, therefore if a heat exchanger is used in the correct way then there is no reason why it shouldn’t be able to remain operational for many years. To help increase the operational lifetime of a heat exchanger there are several steps that should be taken;

Make sure the design data is accurate – If you are sending data to our engineers for heat exchanger selection, then it is best to make sure that it is as accurate as possible. Not only will this ensure that your heat exchanger is thermally efficient but also that it will be able to operate for a long period of time. If the flow rates are too high then erosion could be a problem, if the pressures are too high then leaks could occur and if there are any unusual chemicals in the fluids (such as acids in coolant water) then please contact us to check the compatibility. If our standard materials aren’t suitable then we can usually supply an alternative which is.

Commission and Installation – When installing your heat exchanger, make sure that correct fittings and pipe work are used. If unsure, please check the Thermex Installation and Operation Manual for details. For heat exchangers on applications which use polluted, shallow or brackish sea water as the coolant and have copper alloy tubes, it is recommended to run the heat exchanger in clean sea water for several weeks first, this creates a protective layer over the tube material which helps to protect against corrosion. More information regarding this subject can be found on www.copper.org. Where possible, filters should also be used where fluids may contain solid particles to prevent tube erosion from occurring.

Regular Maintenance and Servicing – All Thermex shell and tube heat exchangers are designed to allow for easy maintenance and servicing. The end caps can be removed allowing the internal tube bundle to be removed for cleaning. New seal kits can also be provided from stock and are available to purchase on our Web Shop. For information and tips on servicing your heat exchanger, please see the Thermex Installation and Operation Manual.


3. What causes a heat exchanger to fail in operation?

There are many possible causes for heat exchanger failure, some examples for shell and tube include;









Below are some abbreviations and terms often used in the heat exchanger industry;Heat Exchanger Abbreviations and Terminology

  • ETD Extreme Temperature Differential
  • EGC Exhaust Gas Cooler
  • MGO Marine Gas Oil Cooler
  • HTHE Header Tank Heat Exchanger
  • CAC Charge Air Cooler
  • ACOC Air Cooled Oil Cooler
  • PHE / PHEX Plate Heat Exchanger
  • Shell Side Flow/Connections – Shell Side refers to the flow of a fluid, such as oil, over the external surface of the tube stack
  • Tube Side Flow/Connection – Tube Side refers to the flow of fluid through the tubes of the tube stack, usually the coolant Pressure Loss / Drop The level of back pressure generated by pumping the fluids through the heat exchanger circuits
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Designing a Heat Exchanger

Designing a Heat Exchanger



1. How is a Heat Exchanger designed?

To be able to select a heat exchanger, we need to know;
  • Primary circuit fluid type, temperature and flow rate (usually the hot fluid)
  • What you want to take out of the primary circuit (Heat dissipation or a target outlet temperature)
  • Secondary circuit fluid type, temperature and flow rate (usually the coolant)


2. Marine Heat Exchangers

The operating principles of a marine heat exchanger are the same as a cooler designed for fresh water use, the main consideration for the designer however is that the marine heat exchanger must be resilient to erosion or corrosion caused by sea water. This means that materials that come in to contact with the sea water must be suitable, such as 90/10 Cupro-Nickel, 70/30 Cupro-Nickel, Bronze and Titanium.

There are other factors which need to be taken in to consideration when a marine heat exchanger is being designed. One is the velocity, if it is too low then there is a risk that sand and other particles will block the tubes. If it is too fast on the other hand then those same particles can rapidly erode the tube plate and tubes.

Additional protection can be provided by installing a sacrificial anode which Thermex can include upon request. This will be installed in to the threaded hole normally used for a drain plug and is in direct contact with the sea water flow.


3. What fluids can a Heat Exchanger operate with?

The suitability of a fluid with a heat exchanger will depend on the type of heat exchanger being used and the materials which are available. Standard Thermex Heat Exchangers are suitable for most fluids including Oil, Water, Water Glycol and Sea Water. For more corrosive fluids such as chlorinated salt water, refrigerants and acids other materials such as Stainless Steel and Titanium will need to be used instead.


4. What is temperature Cross Over?

Temperature cross over is a term used to describe the scenario where the temperatures of both circuits in a liquid cooled heat exchanger begin to cross over. This can be an important factor in a heat exchanger design as the efficiency of a cooler will be significantly reduced when the temperatures cross over. In many cases a plate heat exchanger is the best option for applications where temperature cross over can’t be avoided.








The table above demonstrates that the cooling water outlet temperature is slightly higher than the outlet temperature of the oil. One simple way to combat this and increase the efficiency of the oil cooler is to increase the flow rate of the coolant. In this particular example increasing the water flow rate to 25 L/min would reduce the water outlet temperature to 43°C


5. What is a heat exchanger “pass” and how do I know how many passes I need?

A Heat Exchanger Pass refers to the movement of a fluid from one end of the heat exchanger to the other. For example, when referring to the “through tubes” circuit (usually the coolant); · Single Pass – Fluid enters one end of the heat exchanger, and exits at the other end. · Double Pass – Fluid enters and exists the heat exchanger at the same end. · Triple Pass – Fluid travels the length of the heat exchanger body three times before exiting. The images below will help to demonstrate this;
Single Pass (1 pass)











Double Pass (2 pass)













Triple Pass (3 pass)











  • A greater number of passes increases the amount of heat transfer available, but can also lead to high pressure loss and high velocity.
  • With a full set of operational data, Thermex can select the most efficient heat exchanger possible whilst working within the pressure loss and velocity limits.
  • The number of passes on the primary circuit can also be adjusted to optimise thermal performance and efficiency by changing the baffle quantity and pitch.


6. How to make a heat exchanger more efficient.

Heat exchanger efficiency can be defined in many ways, in terms of thermal performance there are several key factors to consider;

Temperature differential – As discussed in point 3 (temperature cross-over) the difference between the hot fluid and coolant is very important when designing a heat exchanger. The coolant always needs to be at a lower temperature than the hot fluid. Lower coolant temperatures will take more heat out of the hot fluid than warmer coolant temperatures. If you had a glass of drinking water at room temperature for example, it is much more effective to cool it down using ice rather than just cool water, the same principle applies to heat exchangers.

Flow rate – Another important factor is the flows of the fluids in both the primary and the secondary side of the heat exchanger. A greater flow rate will increase the capability of the exchanger to transfer the heat, but a greater flow rate also means greater mass, which can make it more difficult for the energy to be removed as well as increasing velocity and pressure loss.

Installation – The heat exchanger should always be installed based on a manufacturers’ guidelines. Generally speaking the most efficient way to install a heat exchanger is with the fluids flowing in a counter-current arrangement (so if the coolant is travelling left to right, the hot fluid travels right to left) and for shell and tube heat exchangers the coolant should enter at the lowest inlet position (as shown in the diagrams above) to ensure that the heat exchanger is always full of water. For air cooled heat exchangers it is important to consider the air flow when installing a cooler, any part of the core which is blocked will compromise cooling capacity. To find out more about counter-flow and why it is more efficient, please read our blog post “Why counter flow heat exchangers are more efficient”


7. Which industry-specific Heat Exchangers can Thermex provide?

Sometimes, a specific heat exchanger type can be selected based on the industry it will be used for. Some examples include;




















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What is a Heat Exchanger ?

What is a Heat Exchanger ?



1. What is a Heat Exchanger?

Put simply, a heat exchanger is a device which transfers heat from one medium to another, a Hydraulic Oil Cooler or example will remove heat from hot oil by using cold water or air. Alternatively a Swimming Pool Heat Exchanger uses hot water from a boiler or solar heated water circuit to heat the pool water. Heat is transferred by conduction through the exchanger materials which separate the mediums being used. A shell and tube heat exchanger passes fluids through and over tubes, where as an air cooled heat exchanger passes cool air through a core of fins to cool a liquid.

2. What types of Heat Exchanger are available?


There are many different types of heat exchanger available, the three main types that Thermex supplies are;

Marine-Oil-Coolers
Shell and Tube Heat Exchangers consist of a large number of small tubes which are located within a cylindrical shell. The tubes are positioned into the cylinder using a tube bundle or “tube stack” which can either have fixed tube plates (permanently fixed to the body) or, in the case of Thermex Heat Exchangers a floating tube stack which allows the tube bundle to expand and contract with varying heat conditions as well as allowing the tube bundle to be easily removed for servicing and maintenance.

brazed-plate-oil-cooler
Plate Heat Exchangers operate in very much the same way as a shell and tube heat exchanger, using a series of stacked plates rather than tubes. Plate heat exchangers are usually brazed or gasketed depending on the application and fluids being used. Their compact stainless steel construction makes them an ideal choice for use with refrigerants or in food and beverage processing.

Air-Cooled-Section
Air Cooled Heat Exchangers are commonly used in vehicles or other mobile applications where no permanent cool water source is available. Thermex designs and supplies combination cooling packs (or combi-coolers) which combine an engine jacket water cooler, oil cooler and charge air cooler into a single unit reducing space requirements and improving efficiency. Cool air is provided either by a fan or by air flow caused by the movement of the vehicle.



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2017년 4월 2일 일요일

Turbine Cooling Air Cooler



















The thermal energy is transformed to the kinetic energy as steam of high pressure-high temperature rotates steam turbine. Turbine Cooling Air Cooler is used to chill heated gas turbine for maintaining stabilized temperature.

http://www.dh.co.kr/turbine-cooling-air-cooler/

Gas Turbine Air Heater & Cooler



















Gas Turbine Air Heater & Cooler is a heat-exchanger that heats/or chills in-taken air for combustion of gas turbine (the main equipment of the combined cycle power plant). The thermal energy is transformed to the kinetic energy as steam of high pressure-high temperature rotates steam turbine
  • ANSHAN#2 GT AIR HEATER (MHI-T)
  • BAOTOU #1, #2 GT AIR HEATER (MHI-T)
  • UKRAINE #1, #2 GT AIR HEATER (MHI-T)
  • HUNGARY FUNAFERR GT AIR HEATER (MHI-T)
  • QIAN’AN PJT GT AIR HEATER (MHI-T)
  • KRASNODAR RUSSIA GT AIR HEATER (MHI-T)
  • UZBEKISTAN NAVOI GT AIR HEATER (MHI-T)
http://www.dh.co.kr/gas-turbine-air-heater-cooler/

Fuel Gas Heater After Cooler



















This heat-exchanger is used to chill the enclosed circulating cooling water for gas turbine (the main equipment of the combined cycle power plant) around stable temperature.

 http://www.dh.co.kr/fuel-gas-heater-cooler/

Fuel Gas Heater





















Inter Cooler is installed at the end of compressor to chill the compressed gas. This heat-exchanger chills the air or gas discharged from compressor in industrial ASU plant or oil & gas plant, and removes moisture accordingly. Consequently, the efficiency of compressor can be improved and energy can be saved. These air or gas is compressed by cooler at the last stage, and then to be cooled to its required temperature after passing through After Cooler.

Fuel Gas Heater is used to heat fuel gas for gas turbine [the marine equipment of the combined cycle power plant] up to required temperature. The thermal energy is transformed the kinetic energy as steam of high pressure-high temperature rotates steam turbine. Fuel Gas Heater is a heat-exchange that increases a heat-energy of fuel gas and TEMA ‘BFU’ Type is applied.

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