- What are the classifications of heat exchangers?
- How do I choose a heat exchanger?
- How many types of heat exchangers are there?
- How do you increase heat transfer area?
- How the flow rate affects the heat exchanger performance?
- How do you evaluate a heat exchanger performance?
- What is heat transfer surface area?
- What is thermal efficiency formula?
- What is the most efficient heat exchanger?
- What type of flow has better heat transfer in a coil?
- What are the two types of heat exchangers?
- Why counter flow heat exchanger is more effective?
- Why are heat exchangers used?
- What is heat exchanger efficiency?
- What makes a good heat exchanger?
What are the classifications of heat exchangers?
Heat exchangers are classified according to transfer processes into indirect- and direct- contact types.
FIGURE 1.2 (a) Classification according to process function; (b) classification of condensers; (c) classification of liquid-to-vapor phase-change exchangers..
How do I choose a heat exchanger?
Main Criteria for Heat Exchanger Sizing and Selection For a gasketed plate heat exchanger, the gaskets must be compatible with the fluids in the unit. Thermal fluid characteristics and product mix. If the heating or cooling fluid is susceptible to fouling, a corrosion resistant material may be needed. Location.
How many types of heat exchangers are there?
There are two types of heat transfer mechanisms employed by heat exchangers—single-phase or two-phase heat transfer.
How do you increase heat transfer area?
Tangential inserts optimize the velocity of the flow near the tube wall, while providing a bigger heat transfer area. While, increased area and convection coefficient can be achieved by applying spiral fin or ribs inserts.
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.
How do you evaluate a heat exchanger performance?
The simplest indicator of the performance of a heat exchanger is the temperature change of the fluid under consideration. From our high school lessons on thermodynamics, we can recall that the rate of heat transfer is the product of the rate of heat capacity and the temperature change.
What is heat transfer surface area?
Each individual particle on the surface of an object is involved in the heat conduction process. An object with a wider area has more surface particles working to conduct heat. As such, the rate of heat transfer is directly proportional to the surface area through which the heat is being conducted.
What is thermal efficiency formula?
So, for a boiler that produces 210 kW (or 700,000 BTU/h) output for each 300 kW (or 1,000,000 BTU/h) heat-equivalent input, its thermal efficiency is 210/300 = 0.70, or 70%. This means that 30% of the energy is lost to the environment. An electric resistance heater has a thermal efficiency close to 100%.
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. However, a plate heat exchanger regenerator is restricted to low viscosities. With high viscosities, a special tubular may be required.
What type of flow has better heat transfer in a coil?
Each of the three types of heat exchangers (Parallel, Cross and Counter Flow) has advantages and disadvantages. But of the three, the counter flow heat exchanger design is the most efficient when comparing heat transfer rate per unit surface area.
What are the two types of heat exchangers?
What Are The Different Types Of Heat Exchanger?Finned Tube Heat Exchanger Or Air Cooled Heat Exchanger. Suitable for: air/gas to fluid. … Shell And Tube Heat Exchanger. Suitable for: fluid to fluid / fluid to gas. … Plate Heat Exchanger Or Gasket Plate Heat Exchanger. Suitable for: fluid to fluid / fluid to vapour.
Why counter flow heat exchanger is more effective?
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.
Why are heat exchangers used?
Heat exchangers are widely used in industry both for cooling and heating large scale industrial processes. … In many industrial processes there is waste of energy or a heat stream that is being exhausted, heat exchangers can be used to recover this heat and put it to use by heating a different stream in the process.
What is heat exchanger efficiency?
The heat exchanger efficiency is defined as the ratio of the heat transferred in the actual heat exchanger to the heat that would be transferred in the ideal heat exchanger. The concept of heat exchanger efficiency provides a new way for the design and analysis of heat exchangers and heat exchanger networks.
What makes a good heat exchanger?
The heat from one fluid passes across the metal (which is thermally conductive) into the other fluid without the fluids making contact. … High fluid velocity, high turbulence, high surface area and a large temperature differential all contribute to more efficient heat transfer.