Heat cross exchanger

In summary, a heat exchanger is a device that facilitates the transfer of heat between two or more fluids at different temperatures without mixing them. They are widely used in various applications such as heating, cooling, and energy recovery in industries, HVAC systems, and power plants. Heat exchangers can be classified into several types, including shell-and-tube, plate, and air-cooled, each with specific designs and efficiencies tailored to particular operational needs. Their effectiveness is measured by the heat transfer coefficient and the overall thermal performance, making them essential for energy conservation and process optimization.
  • #1
cowboyMorty
1
0
TL;DR Summary
How do I break down this question for inputs for viscosity etc
I have a problem with a cross flow heat exchanger. Hot air enters at 150 degrees at a flow rate of 4.0m^3 s^-1 and a flow speed of 12m s^-1

Water has a flow rate of 0.5kg s^-1 in the tube which has a 50mm diameter

Inlet of the water is 12 degrees and decided outlet is 85

I am confident in my ability to answer the question but having one problem, I have to use an online steam calculator and need help which what prompts to use

My calculator prompts are

Pressure / temperature

Pressure / specific enthalphy

Pressure / specific entropy

Pressure / specific volume

Temperature / specific entropy

Temperature/ quality

Is there something I'm missing, I feel that temperature and specific entropy is the correct one but where do I get my entropy figures?

Any help would be appreciated
 
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  • #2
Welcome to PF, Morty. Is this question for schoolwork?
 
  • #3
Welcome!
Why do we have water, steam and hot air inside the same heat exchanger?
 
  • #4
cowboyMorty said:
TL;DR Summary: How do I break down this question for inputs for viscosity etc

I have a problem with a cross flow heat exchanger. Hot air enters at 150 degrees at a flow rate of 4.0m^3 s^-1 and a flow speed of 12m s^-1

Water has a flow rate of 0.5kg s^-1 in the tube which has a 50mm diameter

Inlet of the water is 12 degrees and decided outlet is 85

I am confident in my ability to answer the question but having one problem, I have to use an online steam calculator and need help which what prompts to use

My calculator prompts are

Pressure / temperature

Pressure / specific enthalphy

Pressure / specific entropy

Pressure / specific volume

Temperature / specific entropy

Temperature/ quality

Is there something I'm missing, I feel that temperature and specific entropy is the correct one but where do I get my entropy figures?

Any help would be appreciated
You will run into more problems, like how many rows of coils the air passes through. Are you feeding the cold water into the back of the coil, the side the air is leaving? One row will probably not extract enough heat from the air to raise the temperature of the water. Most evaporation coils have multiple layers for that reason. It also saves space.

Things like, "Are you recirculating the air?" Mater as well, if you do not want to waste the heat in the air of a single-pass system.

With a multilayer coil, the water leaving the system is polished to perfection on the face of the coil receiving the incoming hot air. Because the water has been pre-warmed by the air that passes through the first layer or layers of the coil.
 

FAQ: Heat cross exchanger

What is a heat exchanger?

A heat exchanger is a device that facilitates the transfer of heat between two or more fluids without mixing them. It is commonly used in various applications such as heating, cooling, and energy recovery in industrial processes, HVAC systems, and power generation.

How does a heat exchanger work?

A heat exchanger works by allowing hot fluid to transfer its heat to a cooler fluid through a series of tubes or plates. The two fluids flow in close proximity, enabling heat transfer through conduction and convection, while remaining physically separated to prevent mixing.

What are the different types of heat exchangers?

There are several types of heat exchangers, including shell and tube, plate, air-cooled, and double-pipe heat exchangers. Each type has its own design and application suitability, depending on factors such as temperature, pressure, and fluid properties.

What are the benefits of using a heat exchanger?

The benefits of using a heat exchanger include improved energy efficiency, reduced operational costs, minimized environmental impact, and enhanced process performance. They allow for effective heat recovery and can contribute to lower energy consumption in various systems.

How do you maintain a heat exchanger?

Maintaining a heat exchanger involves regular inspections, cleaning to remove fouling, checking for leaks, and monitoring performance metrics such as temperature and pressure drops. Proper maintenance ensures optimal efficiency and prolongs the lifespan of the heat exchanger.

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