Method of cooling air and apparatus intended therefor

• US 4,002,040 A
• Filed: 07/17/1974
• Issued: 01/11/1977
• Est. Priority Date: 07/18/1973
• Status: Expired due to Term

• Current Assignee: ABet CARL Munters
• Original Assignee: ABet CARL Munters
• Inventors: Norback, Per, Munters, Carl
• Primary Examiner(s): King, Lloyd L.
• Application Number:
  US05/489,236
• Time in Patent Office: 909 Days
• Field of Search: 62/121, 62/314, 62/309, 62/310, 62/171, 165/60
• US Class Current: 62/121
• CPC Class Codes: F24F 1/0007 Indoor units, e.g. fan coil units self-contained units F24F1/02
• CPC Class Codes: F24F 1/0059 characterised by heat exchangers
• CPC Class Codes: F24F 5/0007 cooling apparatus specially adapted for use in air-conditioning F24F5/0046 takes precedence
• CPC Class Codes: F24F 5/0035 using evaporation
• CPC Class Codes: F28D 5/02 in which the evaporating medium flows in a continuous film or trickles freely over the conduits
• CPC Class Codes: F28F 13/185 Heat-exchange surfaces provided with microstructures or with porous coatings
• CPC Class Codes: F28F 3/02 Elements or assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with recesses, with corrugations F28F3/08 takes precedence
• CPC Class Codes: Y02B 30/54 Free-cooling systems

Abstract

A method and apparatus provides conditioning of an air stream by cooling in a regenerative heat exchanger having two groups of channels separated from one another by walls through which heat exchange occurs. The air stream to be conditioned flows through one group of channels while an auxiliary air stream flows through a second group of channels the walls of which comprise wettable material maintained wet by means of water which is caused to evaporate by the auxiliary air stream to result in cooling. The wettable material provides a substantially stationary liquid layer maintained in the channels of auxiliary air flow so that evaporation takes place directly from the walls separating the two groups of channels to obtain high heat exchange efficiency. The wettable material may be wick-like absorbing material layers which eliminate the requirement of continuously flowing large quantities of water so that the evaporative surfaces may be rewetted intermittently and kept wet over a period of time prior to subsequent rewetting. This is accomplished by providing an excess amount of water. In addition, intensive rinsing of the evaporative surfaces may take place to remove dust particles and mineral deposits occurring in the water. The auxiliary air stream may be split off from the stream of air to be conditioned before and/or after the air stream has been conditioned by cooling to provide greater efficiency.

Claims

1. In a method of conditioning a first air stream by cooling by means of a second auxiliary air stream in a heat exchanger having two groups of channels separated from each other by walls through which heat exchange between the air streams occurs and having wettable material lining the channels through which the auxiliary air stream flows maintained wet by means of water which is caused to evaporate by the auxiliary air stream passing thereover to obtain cooling of the first stream with substantially unchanged moisture content thereof, the improvement providing increased conditioning efficiency comprising the step of applying water to the wettable material intermittently only for a period of time shorter than the period of time in which the evaporation takes place and in an amount in excess of that amount required for replacing the amount evaporated.

2. An improved method according to claim 1 wherein the auxiliary air stream first passes through a heat exchanging means distinct from the regenerative heat exchanger conditioning the first stream.

3. An improved method according to claim 1 in which both the air stream to be conditioned and the auxiliary air stream comprise ambient atmospheric air.

4. An improved method as claimed in claim 1 wherein at least one of the air streams comprises air which has been previously dried.

5. An improved method as claimed in claim 1 wherein at least a portion of the auxiliary air stream comprises a portion of the conditioned air stream which has been cooled in the regenerative heat exchanger.

6. An improved method as claimed in claim 5 in which the auxiliary air stream flows through the wetted channels in two distinct streams, one of which comprises air split off from the conditioned air stream after it has been cooled within the regenerative heat exchanger.

7. The improved method as claimed in claim 6 wherein the heat exchanger includes two zones through which the air to be conditioned passes, in the first zone of which the auxiliary air stream flowing in the wetted channels consists of unconditioned air while in the second zone the auxiliary air stream comprises air which has been split off from the conditioned air stream after it has been cooled by passage through the entire two zones of the regenerative heat exchanger.

8. In a heat exchanger apparatus for conditioning a first stream of air by cooling by a second auxiliary air stream having two groups of channels separated from one another, the walls of which provide heat exchange surfaces for exchanging heat between the two air streams, the channel walls of the auxiliary air stream channels including wettable material maintained wet to permit evaporation by the auxiliary air stream to provide cooling of the wall surface and thus cooling of the air stream to be conditioned with substantially unchanged moisture content, the improvement providing increased heat exchange efficiency comprising means applying water to the wettable material intermittently for a period of time shorter than the period of time in which the evaporation takes place in an amount in excess of that amount required for replacing the amount evaporated.