Heat exchanger Definition and 171 Threads

A heat exchanger is a system used to transfer heat between two or more fluids. Heat exchangers are used in both cooling and heating processes. The fluids may be separated by a solid wall to prevent mixing or they may be in direct contact. They are widely used in space heating, refrigeration, air conditioning, power stations, chemical plants, petrochemical plants, petroleum refineries, natural-gas processing, and sewage treatment. The classic example of a heat exchanger is found in an internal combustion engine in which a circulating fluid known as engine coolant flows through radiator coils and air flows past the coils, which cools the coolant and heats the incoming air. Another example is the heat sink, which is a passive heat exchanger that transfers the heat generated by an electronic or a mechanical device to a fluid medium, often air or a liquid coolant.

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  1. W

    Fluid Flow/Heat Transfer question struggle

    Homework Statement I would really appreciate if someone could help me out with this exercise in fluid flow/heat transfer ,because I really struggling with it.Below I am attaching photo of problem+table with values. Thank you in advance !Homework Equations Question link:[/B]...
  2. C

    How Can I Determine the Maximum Flow Rate for a Heat Exchanger Cooling Oil?

    I'm trying to figure a range of flows of coolant that will pull 200,000 Joules per minute from a heat exchanger cooling oil. The oil is passing through a head that adds 200,000 Joules per minute to 0.5 L / min. The 0.5 L is dumped into a sump with ~7 gallons of oil. The oil then passes...
  3. freddie_mclair

    Cryogenic heat exchanger cooling power

    Hi everyone! I have a silver plated copper heat exchanger (with an internal embedded circuit where liquid nitrogen flows) attached to a bigger aluminium block in order to cool it down. First, I want to estimate it's instantaneous cooling power during cool-down to a stable temperature. I have...
  4. Alfred0812

    How to Start Designing a Plate Heat Exchanger?

    I am currently working on my college project about the design and optimization of plate heat exchanger. However, i have no idea where to start the project. Here is my first thought: - I set the hot and cold fluid to be water, 90 degC for the hot inlet and 30 degC for the cold inlet. - 50mm inlet...
  5. G

    Wall temperature in heat exchanger

    My notes, using an example of a cold tube-side liquid cooling down a hot shell-side liquid stated that: ΔTb = TbS-TbT Mean tube-side wall temperature: TwT=TbT+(tube-side film resistance)/(total resistance) * ΔTb Mean shell-side wall temperature: TwS=TbS-(shell-side film resistance)/(total...
  6. jdawg

    Velocity exiting Heat Exchanger

    Homework Statement Cold air enters a heat exchanger at 400 [K] and exits it at 1200 [K]. At the 0.025 [m2] inlet, the pressure is measured to be 1.0 [MPa] and the velocity is measured to be 3 [m/s]. The area of the exit is also 0.025 [m2] and the pressure here is measured to be 300 [kPa]. What...
  7. Gary K

    Steam Condensation: Calculating Area for Experiment

    Greetings, I'm preparing for an experiment on a modified Tesla Turbine design and will need to condense the exhaust steam rapidly in order to measure the pounds per hour of saturated steam that goes through the system. Incoming steam could be as high as 90 PSI through a 1" pipe. As the turbine...
  8. I

    How Can I Design an Efficient Water Heating System for a High Flow Pool?

    I want to design a water heating system for a special type of pool. The system is open-loop, where input water at 10 C has to be heated to 15 C, and then enters the pool and is eventually exhausted out of the pool. The flow rate is about 100 litres/second (6000 litres/minute). Simply heating up...
  9. H

    Where can I find an NTU equation for a counter flow plate heat exchanger?

    Hi I am woking on a project with dimensioning a plate heat exchanger and are looking at the effectiveness NTU method. The textbooks provide NTU equations for many kinds of heat exchangers but not for plate heat exchangers. Does anyone knows where I can find an NTU equation for a counter flow...
  10. P

    Estimating power required to get heat exchanger up to temperature

    Hi, I am working on a fuel delivery system with multiple heat exchangers, piping, etc. I am trying to determine how much power I will need to heat up the gas in the system at the inlet so that all of the components of my system will reach the operating temperatures. For example, I am looking at...
  11. Davian Francis

    What is the Optimal Water Flow Rate for Designing a Helical Coil Heat Exchanger?

    really need help in designing a helical coil HE. i know i must first do an energy balance to find heat rate.but what next?to find the area needed and the number of turns etc
  12. P

    How to Design a Heat Exchanger Without Knowing Tube and Shell Diameters

    Lets assume an exchanger that is 100% efficient (no heat loss). Duty (Q) and LMTD is known. Your overall heat transfer coefficient (U) is dependent on your transfer coefficients on the shell and tube side, and the resistance of the pipe walls (we're going to ignore entrance effects and fouling)...
  13. D

    Steam Generation Rate of a Heat Exchanger

    Let's say I have a shell and tube heat exchanger that is producing steam. I have a known volume of water entering the shell of the heat exchanger. Would the rate of steam generation be something like... rate of steam generation = (volume of water)*(density of steam)/(time it takes to deplete...
  14. V

    Heat Exchanger Design - Can anyone identify these drawings?

    Hi, I have been asked to create a mechanical drawing of a Shell and Tube Heat Exchanger as part of my course, and have been given some drawings as an example of what mine could look like. I have managed to create drawings on CAD using the example as a target point, however with some of the...
  15. C

    Cross-flow Heat Exchanger 2 phase calculation

    Hi all! I'm working on a project of heating water from exhaust gases of kamin's chimney. I have a cross flow heat exchanger (see pdf). we have done calculations of heat transfer rate and the outlet temerature of the water, and got 150C. so it probably gets boiled somewhere inside the HX. I need...
  16. T

    Spiral heat exchanger - pressure drop?

    Hi, I hope this is the right section. I'm trying to figure out a rough estimate of the pressure drop in a spiral heat exchanger. The fluids both being water. My guess it it would be in terms of the surface area of the inside of the heat exchanger, and the flow rate, but I can't seem to nail...
  17. enginej

    Heat exchangers for power plants

    I'm new to this forum, and would just like to say this is a very impressive site. My question is what is the best path way in school to design heat exchangers for power plants (more geared towards nuclear power plants.) I'm currently finishing my first year of school studying mechanical...
  18. gfd43tg

    Reducing energy consumption and heat exchanger network

    Homework Statement If you are allowed to make changes of column pressure and temperature, stream preheating or cooling temperature, please propose a process change that can significantly reduce the energy consumption at DTmin of 10°C. The modified process should maintain the product quality and...
  19. M

    Simulation error messages solidworks - invalid goals

    I am running a simulation on a flat plate heat exchanger and the solver is coming up with some error messages. The first says that a vortex crosses the pressure opening and the second says that my heat transfer rate goals are invalid. How can I get the heat transfer goals to be valid as I need...
  20. M

    Flat plate heat exchanger - Hand calculations help

    I am designing a flat plate heat exchanger for a project and I am not sure where to start with the hand calculations, specifically the LMTD and E-NTU methods, also how to work out the parameters which i will need to complete these methods such as area and number of plates. My deadline is soon...
  21. y2j

    Plate fin tube heat exchanger design procedure

    Hi anyone have the procedure to design the plate fin tube heat exchanger (air cooler) at defined mass flow rates and inlet / outlet temperatures , or anyone have an software package can be used for this purpose , please can share it with me
  22. R.C

    What are the design considerations for a heat exchanger for an MX5 sports car?

    Hello, I have to design a heat exchanger for my uni course and am a little stuck with where to start. I know a little about LMTD and OHTC etc etc. my main starting problem is finding material properties for ethylene glycol, I have tried Engineering Toolbox but for the maximum temperatures I am...
  23. J

    What is the effect of scaling down a heat exchanger?

    According to this article, it is beneficial to scale down heat exchangers due to the decreased distance the heat has to travel, and therefore the decreased thermal resistance and increased heat flow. "the best way to remove heat from a CPU is to minimize the distance heat must travel from a...
  24. R

    Thermal fatigue for heat exchanger cycle test comparison

    I have a heat exchanger with water/air as medium and we test it in a facility where we cycle the water temperature between 25 to 95 degrees Celcius with a cycle time of 5 minutes for thermal fatigue. Our customer require the testing to be between 5 to 95 degrees instead with 3 minute long...
  25. D

    How Do You Calculate BTUs from Temperature Change in a Heat Exchanger?

    Hello, I'm working with a heat exchanger I'm trying to integrate into a cooling application. I've done some tests but want to have some clear understating of how the calculations are done or if I have missed something. Below is what I have so far. So it's a radiation with 2 pwm fans, they push...
  26. N

    Heat Recovery from Boiler Exhaust Gases

    Homework Statement The exhaust gases from a natural gas-fired central heating boiler leave the boiler at a temperature of 70 deg C. The oxygen content of the exhaust gases is 9% by volume (dry). The rate of energy input (Gross calorific value) to the boiler from natural gas is 16kW. The gross...
  27. M

    Is Fluid Mixing/Seepage Limit a Crucial Specification for Heat Exchangers?

    Is there some specification in manufacturer's literature or some standards about limit of fluid mixing/ seepage through tubesheet of any particular heat exchanger. Is this an important parameter of specification or it does not matter in every application. If such parameter exist, what is its...
  28. D

    Need some helps for a Heat Exchanger Optimization project

    Hello fellow PF members, My teammates and I are working on a project in our Heat Transfer class. It is extremely broad (open ended) and we are not very sure how we should get this project up and going. 1) Project description: We are given an Air Cooled Rankine Cycle. Cooling water, at 70 °C...
  29. P

    Refrigerator Compressors Already have Refrigerant?

    I am a little confused, because I know how refrigerators work with a refrigerant and a compressor and heat exchanges, and I am looking to build one myself, just wondering because I was looking for refrigerator compressors online to buy. Do they have an inlet for refrigerant or is the...
  30. S

    How Does Cooling Water Temperature Affect Heat Exchanger Efficiency?

    Homework Statement A hydraulic fluid initially at 60◦C is cooled to 35◦C using a co-current heat exchanger. Cooling water is available at 15◦C, which must not exceed 30◦C on leaving the heat exchanger. The flow rate of the hydraulic fluid is 1.5 kg/s, which has a specific heat of 5.2 J/gํ C...
  31. X

    Optimizing DIY Air-to-Air Counterflow Heat Exchanger Size with Experimental Data

    Hi I am planning to make a DIY heat exchanger. It will be an air-to-air counterflow heatexchanger with equal air flow. I made a small test heat exchanger so I would be able to estimate the required size of the heat exchanger. I did a small experiment with the small exchanger. The outcome is that...
  32. S

    How to design a radiator to dissipate heat generated by a 39 KW rotary engine?

    No separate coolant is used, instead lubricating oil to be used for both lubrication and cooling of engine. How to calculate radiator size, coolant flow rate?
  33. N

    Hot Air to Cold Oil Heat Exchanger

    Working on a project where we have been asked to utilize waste heat from a combustion process in order to increase the temperature of oil in a separate process. The hot air from combustion is at 340C and the oil is at 22C with a target temperature of 65C I have not seen any hot air heat...
  34. S

    Double pipe heat exchanger sources

    hi I am looking for a complete double pipe heat exchanger thermal and mechanical design. I've found some online sources like this http://scopewe.com/double-pipe-heat-exchanger-design-part-1/ tutorial. and book like process heat transfer by Kern. but I need newer books or online sources. thanks...
  35. F

    Double Pipe Heat Exchanger books

    hello. I am asked to give a lecture on double pipe heat exchanger . I have studied books like process heat transfer by D.Kern and some online articles. I was wondering if other complete sources are available about http://scopewe.com/double-pipe-heat-exchanger-design-part-1/. I would appreciate...
  36. P

    Double pipe heat exchanger design guide

    hi friends, I am going to program a double pipe heat exchanger designer software and I need to every detail on heat transfer and mechanical design considerations. I've read some on double pipe heat exchanger on net like this http://scopewe.com/double-pipe-heat-exchanger-design-part-1/ guide...
  37. K

    Relationship of air dissipating heat from water in a heat exchanger

    I carried out an experiment in a wind tunnel and it shows that as I increase the air velocity the water temperature drop is bigger but the rise in air temperature going through the radiator becomes lesser. Am I wrong to understand that its due to the fact that the air mass flow rate has...
  38. T

    Minimum capacity rate ratio of a heat exchanger

    Homework Statement Here is the question: I am confused about the solution. In the solution they found that the minimum capacity rate ratio R = C_min/C_max was zero. This is because of the term I circled in the red which I do not understand why it goes towards infinity. Here is the solution...
  39. P

    Heat Exchanger Modeling in COMSOL - How to Give Heat Flux at Wall?

    Hi I am trying to model a 3D shell and tube heat exchanger where heat is transferring through the tube wall. For some purpose i have taken the wall thickness to be negligible so i have to give the heat flux at the wall in addition to heat conduction. I have endothermic reaction inside the...
  40. D

    Concentric Tube Heat Exchanger - Clarification on Energy Balance

    I'm trying to model a Transfer function for the response of the deviation in temperature of water coming out of the concentric tube heat exchanger in response to an input velocity of water function. THE PROBLEM I start the derivation with a couple equations in Seborg's Process Dynamics...
  41. O

    Heat Exchanger Metric Formulas

    Hello, I need help to calculate the length of pipe in copper (d=22mm) to get the water in "kolam" to be 45 degree celcius and the heat pump temp is 55 degree celcius, heat pump water flow is about 1 meter cubic per hours, any simple formulas ? thank you for help
  42. J

    Feasibility of Open Heat Exchanger

    Background: I am a Chem Eng student at the University of Houston. I have worked on this problem quite a while but am stuck. Question: A stream of liquid A in an industrial plant, flowing at rate of 2kg/s, needs to be heated from 5 C to 90 C. Another stream or 5kg/s of liquid B, at a...
  43. R

    Heat Exchangers: Advantages of NTU vs LMTD methods in heat exchanger Design

    Hello everyone Exam tomorrow on thermodynmaics and can only find one advantage for the NTU method of design over the LMTD method which is: The NTU method does not rely on using an numerical iterative solution to find the outlet temperatures of the heat exchanger, which would be the case if...
  44. R

    Heat Exchanger Effectiveness and Outlet Temperature Question

    Dear All, I am having trouble getting the effectiveness and outlet temperature for counter flow heat exchanger which is described in the attachment below. I already have the answers but do not know what equations to use to get them. I have equations for the effectives and for the outlet...
  45. R

    Internal heat exchanger on Evaporator

    You can read just bold, or all for further info. :D The COP for a single stage vapour compression refrigerator increases with an increase in evaporating temperature. I would like to to know how it is achieved in reality with the use of an internal heat exch. on the evaporator. Can anyone...
  46. R

    Refrigeration Heat Exchanger Design (Evaporator and Condenser)

    Hi There Based on a Vapour compression refrigeration system: Does anyone out there know a good estimate or any real values for the total heat transfer area for the hot and cold sides of a domestic refrigeration system? i.e. the sum of the areas of the evaporator and the condenser. For the...
  47. R

    Overal heat transfer coefficient: Refrigeration Heat Exchanger

    Hi There Does anyone out there know a good estimate or any real values for the total heat transfer area for the hot and cold sides of a domestic refrigeration system? i.e. the sum of the areas of the evaporator and the condenser. For the Evaporator: QL=UL.AL.(TL-T1) AL=heat transfer...
  48. R

    Refrigeration Heat Exchanger Area Ratio Optimization

    The equation for heat transfer is: 1. Q = U.A.(TL-T1) Where: Q= heat transferred (W). U= overal h.t. coefficient. A= area of heat exhanger (m^2). TL= Temp. of refrigerated space (Kelvin) T1= Low temp. of refrigerant= refrigerant in evaporator (K) I want to eventually find the maximum heat...
  49. R

    Liquid Cooled Heat Exchanger Verification

    My friend and I are trying to design a simple liquid-cooled heat exchanger and I'm getting some odd results so I wanted to get another set of eyes on my math here. We're running four 1.5m sections of nylon tube in parallel through the heat source, which was a thermal input of 265W. The cooling...
  50. C

    End Plate Design For a Heat Exchanger

    I am currently in the process of designing an end-plate for a heat exchanger. I know I can do what I am about to ask with FEA, but that is not feasible right now. Here are the design parameters: Shell and tube HX, Max operating Temp=1100 F, 59 1" SS 304 Tubes, staggered pattern, 12" Shell OD...
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