How Can The Efficiency Of A Heat Exchanger Be Increased?

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..

What is average heat transfer coefficient?

Average heat-transfer coefficient. Heat-transfer coefficient equal to the heat flow (Q) across the heat-transfer surface divided by the average temperature (Δt) and the area of the heat-transfer surface (F)

Why counter flow heat exchangers are more 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. … For example, one fluid may make 2 passes, the other 4 passes.

How can the efficiency of a heat exchanger be improved?

Here are 5 proven industry practices to boost heat exchanger performance and maintain process efficiency:Online and Offline Cleaning. … Maintaining Heat Exchanger. … Periodic Cleaning. … Cleaning the PHE Manually. … Minimizing the Fouling Factor. … Analyzing and Addressing Issues in Heat Exchanger Efficiency.

How the flow rate affects the heat exchanger performance?

On the other hand, an increase in the heat transfer coefficient is observed if the area is maintained constant. Doubling the mass flow rate will result in a 92% increase in the heat transfer coefficient. However, there is a concomitant increase in the pressure drop, proportional to the mass flow rate raised to 0.95.

Does heat transfer increase with flow rate?

In other words, the rate of heat transfer is directly proportional to mass flow rate. If you increase the flow rate, you will then increase the rate of heat transfer.

Which heat exchanger is more 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.

How do you increase overall heat transfer coefficient?

To increase heat-transfer rates, the velocity through a jacket can be increased by recirculating the cooling or heating liquid. For simple jackets without baffles, heat-transfer will be mainly by natural convection and the heat-transfer coefficient will range from 200 to 400 W/m2 °C.

Does turbulence increase heat transfer?

The heat transfer coefficient increases when the fluid velocity increases (better mixing in the turbulent boundary layer, thinner laminar su-blayer). … A turbulent flow increases the amount of air resistance and noise; however, a turbulent flow also accelerates heat conduction and thermal mixing.

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.

What does the overall heat transfer coefficient depend on?

Heat transfer coefficient depends on both the thermal properties of a medium, the hydrodynamic characteristics of its flow, and the hydrodynamic and thermal boundary conditions.

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 heat exchanger performance?

4.0 – HEAT EXCHANGERS CALCULATIONS:The main basic Heat Exchanger equation is: Q = U x A x ΔTm =The log mean temperature difference ΔTm is: ΔTm =(T1 – t2) – (T2 – t1) = °F.T1 = Inlet tube side fluid temperature; t2 = Outlet shell side fluid temperature;ln (T1 – t2) (T2 – t1)

What is overall heat transfer coefficient?

The overall heat transfer coefficient, or U-value, refers to how well heat is conducted through over a series of resistant mediums. Its units are the W/(m2°C) [Btu/(hr-ft2°F)].

What are the two types of heat exchangers?

There are two main types of regenerative heat exchangers—static heat exchangers and dynamic heat exchangers.