Direct Contact Heat Exchangers
Direct contact heat exchangers involve heat transfer between hot and cold streams of two phases in the absence of a separating wall. Thus such heat exchangers can be classified as:
- Gas – liquid
- Immiscible liquid – liquid
- Solid-liquid or solid – gas
Most direct contact heat exchangers fall under the Gas- Liquid category, where heat is transferred between a gas and liquid in the form of drops, films or sprays.
Such types of heat exchangers are used predominantly in air conditioning, humidification, industrial hot water heating, water cooling and condensing plants.
| Phases | Continuous phase | Driving force | Change of phase | Examples |
|---|---|---|---|---|
| Gas – Liquid | Gas | Gravity | No | Spray columns, packed columns |
| Yes | Cooling towers, falling droplet evaporators | |||
| Forced | No | Spray coolers/quenchers | ||
| Liquid flow | Yes | Spray condensers/evaporation, jet condensers | ||
| Liquid | Gravity | No | Bubble columns, perforated tray columns | |
| Yes | Bubble column condensers | |||
| Forced | No | Gas spargers | ||
| Gas flow | Yes | Direct contact evaporators, submerged combustion |
Read more about this topic: Heat Exchanger
Famous quotes containing the words direct, contact and/or heat:
“The most passionate, consistent, extreme and implacable enemy of the Enlightenment and ... all forms of rationalism ... was Johann Georg Hamann. His influence, direct and indirect, upon the romantic revolt against universalism and scientific method ... was considerable and perhaps crucial.”
—Isaiah Berlin (b. 1909)
“Dr. Scofield’s equipment, which you have just seen, radiated waves direct to Professor Houghland’s laboratory. When these waves came in contact with those the professor’s equipment was radiating, they created the interstellar frequency, which is the death ray.”
—Joseph O’Donnell, and Clifford Sanforth. Arthur Perry (Bela Lugosi)
“As in hoary winter’s night stood shivering in the snow,
Surprised I was with sudden heat which made my heart to glow;
And lifting up a fearful eye to view what fire was near,
A pretty Babe all burning bright did in the air appear;”
—Robert Southwell (1561?–1595)