How does the direction of flow affect heat exchanger performance?
[5] reported the effect of water flow direction in a vertical plate fin heat exchanger with refrigerant upward flow on heat transfer performance. They concluded that the parallel flow arrangement produced higher heat transfer performance than the counter flow arrangement.
How do you know if a heat exchanger is parallel or counterflow?
A counter-flow heat exchanger is one in which the direction of the flow of one of the working fluids is opposite to the direction to the flow of the other fluid. In a parallel flow exchanger, both fluids in the heat exchanger flow in the same direction.
What is the main purpose of a secondary heat exchanger?
The secondary heat exchanger is where the flue gas undergoes further heat exchange and water vapor forms. After exiting the primary heat exchanger, the burning gas proceeds to the secondary heat exchanger. As water is changed from a vapor to a liquid, it releases more heat into the secondary heat exchanger.
What are the disadvantages of plate heat exchangers?
DISADVANTAGES OF PLATE HEAT EXCHANGERS
- Leakage. Plate heat exchangers are designed to allow plates and gaskets to be inserted between them. …
- Higher pressure drops. …
- Not beneficial for large fluid temperatures. …
- It doesn’t work well with very high fluid temperatures.
How do you fix a heat exchanger problem?
Quote from the video:
Quote from Youtube video: The problem reads two fluids a and B enter a very long co-current flow a concentric tube heat exchanger under the conditions listed in the table below the process is at steady state.
Which heat exchanger is most efficient?
Plate exchanger is the most efficient due to turbulent flow on both sides. High heat-transfer coefficient and high turbulence due to even flow distribution are important. However, a plate heat exchanger regenerator is restricted to low viscosities. With high viscosities, a special tubular may be required.
Why is parallel flow not efficient?
The key difference between counterflow and parallel flow heat exchanger is that counterflow heat exchanger is highly efficient because it can exchange a maximum amount of heat, whereas parallel flow heat exchanger is less efficient because it cannot exchange a high amount of temperature.
What are the advantages of parallel flow heat exchanger?
While less efficient, the main advantage of parallel heat exchangers is that the exit temperature of the two fluids, and therefore their energies, will be closer to one another than they would be in counter-flow exchangers.
How does a parallel flow heat exchanger work?
This flow arrangement is called parallel flow. Heat is transferred from the warm fluid through the wall of the inner tube (the so-called heating surface) to the cold fluid. A heat exchanger can also be operated in counterflow, in which the two fluids flow in parallel but opposite directions.
Can plate heat exchanger operate at high temperature?
Gaskets, in addition to their sealing effect, serve to direct the flow of the fluids, and are placed along the grooves at the edges of the plates. The maximum temperatures used for sealing heat exchangers are between 80°C and 200°C while pressures can reach 25 bar.
How efficient are plate heat exchangers?
With those factors embedded into industry calculations, plate heat exchangers are still consistently found to be the most efficient of all heat exchangers. Typically, they can achieve efficiency rates of approximately 90%.
What is the purpose of gasket in plate heat exchanger?
Gaskets act as seals between the plates. Fluids normally run counter-currently through the heat exchanger. This gives the most efficient thermal performance and enables a very close temperature approach, ie the temperature difference between the exiting process medium and the entering service medium.
What are the symptoms of a damaged heat exchanger?
Six Signs Your Furnace Heat Exchanger May be Cracked
- Strange smells. A malfunctioning heat exchanger will often create an unpleasant and strong odor that smells similar to formaldehyde.
- Soot Build-up. …
- Corrosion & Cracks. …
- Change in the flame appearance. …
- Audible Sounds. …
- Presence of Carbon Monoxide.
What are common problems or malfunctions encountered with a heat exchanger?
Some of the most common heat exchanger problems for many process plants include the following;
- Vibration issues.
- Exchanger leakage.
- Increasing exchanger energy consumption.
- Pass Partition bypassing (thermal leakage)
- Air cooler air recirculation.
- Fouling.
What causes heat exchanger failure?
Corrosion is a common cause of heat exchanger failure in process applications. The mechanisms of corrosion-induced failure include pitting corrosion, galvanic corrosion and condensate grooving.
How do I test a heat exchanger?
Quote from the video:
Quote from Youtube video: And easiest ways to test them while it's true we can disassemble the heat exchanger take the manifold. The burners out and do a visual inspection.
How do I know if my heat exchanger is clogged?
A Pungent Odor
This smell will most likely be a sulfur-like smell or burning rubber smell due to soot or corroded polypropylene in the tubes of the blocked secondary heat exchanger. You might notice this odor leaking inside your home near the furnace – if the heat exchanger is significantly blocked.
Can a heat exchanger be cleaned?
Cleaning-In-Place (CIP) equipment can clean plate heat exchangers without disassembly. CIP is a combination of time, temperature and concentration. CIP provides both chemical and mechanical cleaning to the heat exchanger. If system configuration prohibits CIP, operators must perform manual cleaning.
What causes clogged secondary heat exchanger?
Quote from the video:
Quote from Youtube video: So what's happening is the heat exchanger got clogged up because of the lack of enough oxygen you're running too rich. And this furnace the exhaust was starting to get stinky. And that's the clue that
How much does it cost to replace a secondary heat exchanger?
$1,000 to $2,000
Replacing a secondary heat exchanger costs $1,000 to $2,000, depending on the brand, material, and furnace capacity. The secondary heat exchanger part alone costs $300 to $800. Some high-efficiency models use a secondary heat exchanger to reclaim the heat from the combustion gasses that normally vent to the outside.
