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. … Each time a fluid moves through the length is known as a pass.
Why is counter current better?
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).
Which flow is better in heat exchanger?
Where two fluids are expected to be taken to exactly the same temperature, the
parallel flow configuration
is beneficial. While the counter flow heat exchanger has more significant advantages compare to parallel flow design.
Which flow pattern is more efficient for heat transfer?
The counter flow pattern
is the most common in shell and tube heat exchangers, primarily because it's the most efficient. This flow pattern allows for the greatest temperature change between fluids.
Why the counter flow is preferable than the parallel flow in condensers?
Counter flow heat exchangers are the most efficient of the three types. In contrast to the parallel flow heat exchanger, the counter flow heat exchanger
can have the hottest cold- fluid temperature greater than the coldest hot-fluid temperatue
.
Why counter flow heat exchanger is most efficient?
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
. … Each time a fluid moves through the length is known as a pass.
What is counter flowing flowing?
With a counter flow arrangement,
the cooling medium flows in the opposite direction to the liquid being cooled
. Find out why this so much more efficient. In a shell and tube heat exchanger, coolant usually flows through the central ‘tube core' to cool hot oil, water or air, which passes over and around the tubes.
Why do we use lmtd in heat exchanger?
The log mean temperature difference (LMTD) is used
to determine the temperature driving force for heat transfer in flow systems
, most notably in heat exchangers. The LMTD is a logarithmic average of the temperature difference between the hot and cold streams at each end of the exchanger.
How do you calculate effective heat exchanger?
If one of the fluids is undergoing a change of phase throughout the entire heat exchanger and at a constant temperature (i.e. heat capacity is infinite), the thermal efficiency is simply
Eff=1-exp(-U.A/Cmin)
, where Cmin is the heat capacity (m x cp) for the single phase fluid, U-overall heat transfer coeffcient and A …
What is counter flow in heat transfer?
As a brief description; the term refers to
the relationship between the flow directions of the hot and cold fluids
. With parallel flow the fluids are travelling through the heat exchanger in the same direction where as a counter flow installation will have the fluids flowing against each other in opposite directions.
What is the most effective 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. However, a plate heat exchanger regenerator is restricted to low viscosities.
What is GREY body in heat transfer?
A gray body is
an imperfect black body
; i.e., a physical object that partially absorbs incident electromagnetic radiation. The ratio of a gray body's thermal radiation to a black body's thermal radiation at the same temperature is called the emissivity of the gray body.
What is difference between parallel flow and counter flow heat exchanger?
Counter & Parallel Flow Heat Exchanger Calculator
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 advantage of counter current flow over co current flow in a heat exchanger?
One of the great advantages of counter-current flow is
the possibility of extracting a higher proportion of the heat content of the heating fluid
. It is important to note that the LMTD value for counter-current flow is much larger than for cocurrent flow at the same terminal temperature (see Figure 1.9).
What is the difference between co current heat exchanger and counter current heat exchanger?
One is termed a cocurrent heat exchanger, while the other is termed a countercurrent heat exchanger. In the cocurrent mode, both the hot and cold streams enter the heat exchanger at one end, and leave at the opposite end. In the countercurrent mode, the streams enter at opposite ends of the heat exchanger.
What is counter current heat exchange?
Countercurrent exchange is
the transport of heat or chemicals between fluids moving in opposite directions separated by a permeable barrier
(such as blood within adjacent blood vessels flowing in opposite directions).
