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.
Which is better counterflow or parallel flow?
Counter flow heat exchangers are inherently more efficient than parallel flow heat exchangers because they create a more uniform temperature difference between the fluids, over the entire length of the fluid path.
What does parallel flow mean?
A parallel flow pattern, also referred to as a cocurrent flow, is one in which the shellside and tubeside fluids flow in the same direction. This is widely seen in double-pipe heat exchangers and can be replicated in shell and tube heat exchangers as well, according to Bright Hub Engineering.
What are the advantages of a parallel flow system?
Parallel flow is similar to a electrical parallel circuit in which several parallel flow circuits of equal length connect to a supply header and a return header. A benefit of parallel is that a small diameter pipe can be used due to lower pressure drops and same money on installation.
How does parallel flow differ from counter flow?
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.
Why is countercurrent flow better than parallel flow in dialysis?
The counter-current flow of the blood and dialysate maximizes the concentration gradient of solutes between the blood and dialysate, which helps to remove more urea and creatinine from the blood.
Why is countercurrent flow more efficient than co current?
The maximum amount of heat or mass transfer that can be obtained is higher with countercurrent than co-current (parallel) exchange because countercurrent maintains a slowly declining difference or gradient (usually temperature or concentration difference).
What is the most efficient heat exchanger?
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.
What are the advantages of parallel flow heat exchanger?
While parallel flow arrangement can be beneficial, under certain conditions that reduce the limiting temperature, channeling problems can occur or freeze may be caused at shutdown. Thus, parallel flow in heat exchangers minimizes the chance of freezing or channeling, but does not eliminate the possibility of either.
Where is parallel flow used?
The parallel flow heat exchanger is mainly used where limited transfer of heat is recommended. The limit of the exit temperature of cold fluid is exit temperature of hot fluid in case of parallel flow heat exchanger.
What is one of the disadvantages of a series loop piping system?
Series system
Disadvantages include: Larger water or antifreeze volume of larger pipe, higher price per foot of piping material, increased installed labor cost, limited length due to fluid pressure drop and pumping costs.
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 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.
What is the highest efficiency of parallel flow heat exchanger?
What is the maximum efficiency for parallel flow heat exchanger? Explanation: No matter how large the exchanger be or how high be the flow of overflow at transfer coefficient, the maximum efficiency for parallel flow heat exchanger is 5%.
How do you calculate parallel flow in heat exchanger?
Quote from the video:
Quote from Youtube video: Times its heat capacity times the change in temperature from the start to the end of the heat exchanger.
What determines the flow pattern in exchangers?
The shell side flow pattern is determined by baffles as shown in the diagrams. heat exchanger, with the fluid making a ‘u-turn’ through tube bends at the other end, as shown in the upper diagram at the right. A u-tube shell and tube heat exchanger will automatically have two tube passes.
How do I calculate flow rate?
If you can see the fluid flowing, you can measure its velocity, and that means all you need is the area through which the fluid is flowing to calculate the flow rate using the formula Q = A × v.
Why is the counterflow heat exchanger configuration preferred over the parallel type?
The best design for shell and tube and double-pipe exchanger is counter flow configuration, and the heat transfer between the fluid is the maximum. In counter flow, the efficiency is higher than the parallel, and temperature in the cooling fluid outlet can exceed the warmer fluid inlet temperature.
Is countercurrent flow efficient?
By contrast, counter flow is significantly more efficient and, depending on the flow rate and temperature, the heat transfer performance could be up to 15% more efficient, possibly enabling a smaller heat exchanger to be used, saving space and money!
