Quick Answer: Why Counter Flow Heat Exchanger Is More Effective?

What affects heat exchanger efficiency?

Heat exchanger efficiency is highly affected by the velocity of the operating fluid so it is recommended that the flow rate should be increased from time to time.

The increased turbulence works to retard fouling tendencies that otherwise impact heat exchanger performance and impede the flow of fluids..

How can you make a heat exchanger more efficient?

In general, the most efficient way to install a heat exchanger is to flow the fluid in a countercurrent arrangement (so that if the coolant travels from left to right and the hot fluid travels from right to left), and for shell and tube heat exchangers, The agent should enter the lowest inlet position (as shown above) …

Under which condition you will select parallel flow and counterflow heat exchanger?

For the same inlet and outlet temperatures, the log mean temperature difference for counter flow exceeds that for parallel flow. Hence the surface area required to effect a prescribed heat transfer rate q is smaller for the counter flow than for the parallel flow arrangement, assuming the same value of U.

Which heat exchanger is more effective?

“The counter flow pattern in shell and tube heat exchangers is the most efficient.” 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 is one way flow an advantage to fish?

2. Because water is more vicious than air, it takes more energy to ventilate and swim through it. This causes an increase in demand for oxygen, and therefore fish have a continuous unidirectional flow of water over their gills for maximum diffusion efficiency.

How the flow rate affects the heat exchanger performance?

The effect of the mass flow rate at constant velocity on the convective heat transfer coefficient of an incompressible fluid in a turbulent flow regime is presented with the help of dimensional analysis. … Doubling the mass flow rate will result in a 92% increase in the heat transfer coefficient.

What is the advantage of counter flow system?

The counter-flow heat exchanger has three significant advantages over the parallel flow design. First, the more uniform temperature difference between the two fluids minimizes the thermal stresses throughout the exchanger.

Under what conditions can a counter flow heat exchanger have an effectiveness of one?

When capacity ratio is equal to one and NTU value is very large then the counter flow heat exchanger will have an effectiveness of one i.e. 100% effectiveness.

How do I choose a heat exchanger?

The following criteria can help in selecting the type of heat exchanger best suited for a given process:Application (i.e. sensible vapor or liquid, condensing or boiling)Operating pressures & temperatures (including startup, shutdown, normal & process upset conditions)More items…

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 the difference between mixed and unmixed fluids in cross flow?

“Mixed” and “unmixed” refer to cross-flow heat exchangers, where the main direction of each flow is the transversal of the other. “Mixed” means than the fluid temperature is equalized in the transverse direction due to intense (turbulent) mixing, so that its temperature only varies in its the main direction.

What is the difference between co current heat exchanger and counter current heat exchanger?

In counter-current heat exchangers, the hot and cold fluid flow in opposite directions in the heat exchanger. This is in contrast to the co-current heat exchanger where the hot and cold fluids flow in the same direction along the length of the heat exchanger.

What is counter flow cooling tower?

A counterflow mechanism is one where air flows vertically through the fillings or packing at the top while water flows downward. In a counterflow cooling tower, there is an induced draught fan that is attached to the motor.

How efficient are plate heat exchangers?

Efficient heat transfer: The corrugations of the plates and the small hydraulic diameter enhance the formation of turbulent flow, so that high rates of heat transfer can be obtained for the fluids. Consequently, up to 90% of the heat can be recovered, compared to only 50% in the case of shell-and-tube heat exchangers.