US2445705A

US2445705A - Air conditioning apparatus

Info

Publication number: US2445705A
Authority: US
Publication date: 1948-07-20
Anticipated expiration: 1965-07-20

Description

July 20, 1948. N, wElNsTlN- ETAL 2,445,705

AIR CONDITIONING APPARTUS Filed June 1o, 1944 INVENTOR BY J 71( WM ATroRNEY Patented .luly 20, 1948 oFFicE 'AIR CONDITIONING APPARATUS Norman Weinstein and Gerald F. Mannion, v

Chicago, lll.

Application June 10, 1944, Serial No. 539,707

Claims. (Cl. 62-6) The object of our invention is to provide an apparatus for conditioning air or gas, particularly when this air or gas must be conditioned to a temperature at or below the frost point.

Another object of our invention is to provide a sequence of cooling and reheating stages for conditioning air or gas whereby the air or gas may be economically dehumidied and reheated in a comparatively small space.

Another object of our invention is to provide an apparatus which will condition air or gas by dehumidifying it and subsequently reheating it so that the air or gas conditioned will have a continuously uniform moisture content and dry bulb i temperature.

Another object of our invention is to provide a means of control whereby the conditioned air or gas will be uniform as to moisture content and dry bulb temperature.

Another object of our invention is to provide an apparatus which will allow air or gas conditioned below the frost point to deliver this air or gas on a continual basis without the necessity of using more than one system of apparatus for the purpose.

Another object of our invention is to provide an apparatus which will allow air or gas conditioned below the frost point to be delivered on a. continual basis without the necessity of shutting down the apparatus for defrosting.

Another object of our invention is to provide an apparatus to deliver a continual flow of air or gas at a constant condition and at the same time require the use of less refrigeration capacity than normally required.

It is well known that in the use of air or gas where this air or gas must be dehumidifled to a condition at or below the frost point that a duplexing of equipment is required so that the air or gas can be delivered constantly without shutting down for removal of ice or frost accumulations.

' At the same time the total amount of refrigeration The flow of gas or air through our apparatus differs from that previously used or invented mainly in the following feature: y

Coils 2I and 23 are identical. Coil 2| is used as the nal cooler when gas or air is routed through duct I5. During this cycle coil 23 is be- 2 ing defrosted. Coil 23 is used as final cooler when gas or air is routed through duct Il. During this cycle coil 2l is being defrosted.

Our invention is not limited to this one feature-but stress is placed on it to clarify the typical example which is given below:

The gure shows diagrammatically the means of accomplishing our invention. Referring to the gure, I2 represents an inlet duct or pipe wherefrom air or gas is moved by fan I I through either conduits I5or I 6, then through casing I2. then through either conduits I5 or I6 to outlet duct I1. The casing I3 which may be in either a horizontal or vertical position, and is shown In the figure to be raised from the ground by supports I0.

As a typical illustration, assume the following conditions:

Gas at F. saturated is to be conditioned to 25 F. saturated when leaving coil 2| into the duct I6 or leaving coil 23 into duct I5.

This 70 gas enters apparatus through duct I2, into duct I5, through transfer valve I4, then into casing I3.

Gas then passes over coil 23, defrosting that coil provided a previous cycle has occurred.

The gas then passes over coil 22, and is reduced to 57.5 F. saturated. Gas then flows over coil 2l and is reduced to 25 F. saturated.

Gas then leaves casing I3, travels through duct I6, through transfer valve I4, and through duct I8 In this problem, the sole purpose of reducing the gas temperature to 25 F. saturated is the elimination ofvmoisture. Any sensible heat pickup, after that accomplishment, is a gain. Therefore, gas now travels through heating coil 24 which is interposed in duct I8. This coil (24) is connected by pipe circuits 30 and 3I to cooling coil 22, to form a heat reclamation cycle. A pump 26 is intenposed in the pipe circuit (30 and 3|) to circulate the heat exchange medium from c0111.* ing coil 22 to heating coil 24, and backv again.

Heating coil 24 restores to the gas as sensible heat both the latent and sensible heat which cooling coil 22 abstracted. Thus the gas has been dehumidied to the equivalent of 25 F. saturated. but leaves apparatus with part of the sensible heat restored which had to be removed for dehumidiflcation.

Conversely, this h'eat reclamation causes the heat exchange medium to be reduced in temperature by the passage of 25 F. gas over heating coil 24. The heat exchange medium, thus reduced in temperature, is returned to coll 22 at a lower temperature than that at which it left this same coil, thus causing a direct saving in the amount of refrigeration required to reduce the gas temperature to 25 F.

Coils

24 and 22 need only be used when de- 3 sired to raise the outlet temperature of air emit-A ting either from coils 2| or 23.

In this problem the gas now leaves apparatus through duct I1 at a dew point temperature of 25 F. but a dry bulb temperature of 60 F,

As in all refrigeration dehumidifying apparatus where it is necessary to use a cooling medium at or below the frost point, ice or frost will form on the coil or other apparatus used for heat transfer purposes. In this problem ice has gradually accumulated on coil 2| until its effectiveness as a transfer medium is about to be impaired. The defrosting of coil 2| and the simultaneous transfer of the function of deh'umidiiying and cooling from coil 2| to coil 23, occurs as follows:

The cooling coils 2| and '23 are supplied with a cold heat exchange medium, preferably brine from the refrigeration unit 2B, through a pipe circuit 42, the ow being controlled by valve 44. The brine circuit is formed by the supply pipe 13 from the refrigeration unit 28 to the valve 44 which selectively allows the ow of cooling medium to coil 2| and sh'uts oi the iiow of cooling medium to coil 23, and when actuated by the motor 10 will shut off the ow of cooling medium to coil 2| and allow the flow of cooling medium to coil 23.

The cooling medium is returned from coil 2| to conduit 16 through conduit 14 and the cooling medium is returned from coil 23 to conduit 16 through return conduit 15. A pump 11 is interposed in the return conduit 16 to pull the cooling medium from the coils back to the refrigerating unit 28. Interposed in the line 13 is a valve 80, operated by a motor 19, actuated by the power line 13, responsive to the thermostat 40 to regulate the amount of flow of the brine. In the sequence of operation described, the cold heat exchange medium is only supplied to coil 2|, the ilow of this medium being shut oi to coil 23 by valve 44. As accumulations of ice and frost on coil 2| develop and a reversal of the flow f the gas is made through the actuation of transfer valve I4, causing the air or gas entering casing I3 to pass through inlet I6 instead of inlet I5. At the same time valve 44 is -actuated to shift the iiow of the cold brine from coil 2| to coil 23. At the same time valves 68 and 69 in pipe circuit 30 and 3| operate to divert the flow of the heat exchange medium in pipe circuit 30 and 3| through pipe 34 and pipe 35 so that a reversal of flow of this heat exchange medium takes place in cooling coil 22. The operation of the valves mentioned above may be accomplished either through an air supply source and air conduits such as 6I, 62, 83, 34, 65, 66, 13, etc., as shown, or may be accomplished by other well known means such as, for example, an electrical/circuit (not shown). It is advantageous in heat exchange, from a heat exchange medium to air using a multirow coil, that th'e coolest portion of heat exchange medium be in contact with the leaving air, .and thus when the direction of the ow of air through the coil (a multirow coil) is changed, the direction of the ilow of the heat exchange medium through th'e coll should be changed. so that the warmest portion of the heat exchange medium be in contact with the entering air, and the coolest portion of the heating medium be in contact with' the leav ing air.

When the ow of air through the coil 22 is reversed it is also desirable to reverse the ilow of heat exchange iiuid medium through coil 22, without reversing the ilow of heat exchange medium through' coil 24. This is accomplished by the said two

way valves

33 and 69, whereby when the air enters through conduit I5, the valve 3l would allow a ilow of heat exchange fluid from conduit 3| through conduit 12, through a multirow coil 22, out through conduit 1I through pump 36 and conduit 30. In this positiorrvalve 63 prevents any fiow through conduit 35, and valve 68 prevents any flow through conduit 34.

When the air enters through conduit I4, the iiow of heating exchange medium through coil 22 is reversed by

valves

63 and 69, whereby the valve 58 allows a. flow of heat exchange medium from conduit 3| through conduit 35 and a portion of conduit 1|. then through the multirow coil 22 and out through 12, then through conduit 34 and through the valve 69, pump 36 and conduit 30. In the last operation the position of the valves 68 and 69 are both changed from the first operation and shuts oil the ow of heat exchange medium from conduit 3| to conduit 12 and allows the iiow of heat exchange medium from conduit 3| through conduit 35v while the position of valve 69 shuts off the ilow of heat exchange medium from that portion of conduit 1| between the valve 69 and coll 22.

The direction of ilow through the valve 63 is aiways from conduit 3| through the valve either to the conduit 12 or the conduit 35, depending `upon the position of the two-way valve 68, and

the direction of th'e flow through the valve 63 is always toward the pump 36, with the inlet open to allow flow either from conduit 34 or from that portion of conduit 12 between the valve 69 and.

' eration of valves 68 and 69. The same electrical circuit 63 operates the motor 5|, controlling damper I4, and motor 33. operating valve 69, and motor 32 operating valve.68, so that

valves

63 and 69 are actuated simultaneously with the operation of damper I4.

From duct or pipe I2, the gas passes through transfer valve I4, through pipe or duct I6, into casing I3. As this gas Stream passes over coil 2|, the accumulated ice and frost is melted oi and drained out of casing I3. The gas stream then iiows over coil 22 where its temperature is reduced from '10 F. saturated to 57.5 F. saturated. This gas then iiows over coil 23 where its temperature is further reduced to 25 F. saturated. The stream of air or gas then flows through duct or'pipe I5 from casing I3 through transfer valve I4, and then over reheatlng coil 24, where the latent and sensible heat that is removed by coil 22 is added to the air or gas as sensible heat.

As ice and frost begin to accumulate on coil 23 in the described sequence of operation, transfer valve is again actuated and the iiow of air or gas is again reversed through apparatus casing I3. At the same time valve 44 in pipe circuit 42 is actuated to stop the iiow of brine through coil 23 and allow the dow of brine to go through coil 2|. Valve 63 and valve 63 in pipe circuit 30 and 3| are also actuated so that the ilow of the heat exchange medium through coil 22 is reversed. It is apparent from th'e above description that through the method of operation herein used that our invention gives a continual operating apparatus for the delivery of air or gas at dew points as low as the frost point or lower without the necessity of shutting down the apparatus for deicing or defrosting or for the necessity of duplexlng the apparatus.

In order to show further advantages o! the apparatus which we describe herein, we refer to a typical problem of cooling 10,000 C. F. M. of free air or gas which on entering our apparatus at '10 F. saturated leaves at a final condition of 60 F. dry bulb and 25 F. dew point. 'Ihe conditioning of the air or gas as set forth in the above example could be obtained by means of a single cooling coil such as coil 2| or 23 with a refrigeration requirement of 90 tons being necessary. However, by means' of our method or dehumidifying and reheating we are able to reduce the refrigeration load from 90 tons to 56 tons and at the same time deliver this gas or air at the same dew point. i

A thermostat 40 responsive to the temperature of th'e air in conduit I8 controls the operation of the valve 44 so as tb selectively direct the ilow of brine either to coil 23 or coil 2I, and also controls the operation of transfer valve or damper I4, so as to selectively direct the flow of air to be conditioned either through duct I5 or duct I6, and also controls operation of the valves 68 and 63, so as to selectively direct the flow of heat exchange medium to coil 24 either through pipe 3l or pipe 30. Assuming that the coil 23 becomes frosted as to impair th'e operation of the coll, the result in most cases wouldV be to reduce the quantity oi' air being able to pass the coil with a resultant lower dry bulb temperature. Assuming the thermostat 40 to be set so that a reduction in the dry bulb temperature of the air in conduit I8 will cause the thermostat to activate the motors controlling valve I4, valve 44 and valves 68 and 69 through the

lines

6I, 62, 63, 64, 65 and 66. The motors are of the commercially reversible type and a time relay 61 (also commercially known) is interposed in the line 6I, so as to preclude any further operation of the motors until suflicient time has elapsed to allow the new cycle to take effect and raise the temperature of the air surrounding thermostat 40, and then when the thermostat 40 again activates line 6I to cause the motors controlling the operation of valves I4, 68, 69 and 44 to reverse their operation. The motor controlling the valve I4 is designated as 5I. The motor 32 controls the valve 68, the motor 33 controls th'e valve 69 and the motor 10 controls the valve 44.

The valve or damper I4 is shown by the curved blade 50, which allows flow of air from conduit I2 to conduit I5 and-from conduit I6 to conduit I6. A 90 revolution of the blade 50, as is shown by the dotted lines, will cause the air from conduit I2 to flow through conduit I6 andthe air from conduit I5 to flow through conduit I6.

The valve 44 is a two way valve, which in one position supplies refrigerant to coil 23 and sh'uts off the flow to coil 2| and when revolved by the motor 'I0 will cut olf the supply to coil 23 and supply refrigerant to coil 2I.

The valve 69 is a two way valve in one position to supply heat exchange fluid to coil 22 through pipe 1I and in the second position to -cut off the supply of heat exchange fluid to .pipe 'II and to supply said fluid to coil 22 through pipe 34.

Valve 68 is a similar twoway valve, which in one position allows a flow of uid from coil 22 through lines 1I, 35 and 3| to coil 24, and in another position allows a flow of fluid from coil 22 through lines 12 and 3I to coil 24.

The damper I4 is circular operatively connected with conduits I2, I5, I6 and I8, so that the position of the blade or damper It will selectively dlrect the air from conduit I2 to either conduit Il or I6.

If it is desired to control the operation oi' the 5 said :rotors and valves responsive to an interval of time. then a device designed to operate a motor upon the lapse of a predetermined interval of time may be substituted for thermostat 40, or an instrument responsive to the accumulation of frost on cooling coils 2| or 23 may be substituted for the thermostat 4II. We claim: )1. An air conditioning apparatus comprising a casing with vair inlet and outlet, means to move air therethrough, two cooling coils interposed in said casing in the path of said air, and meansto reverse the flow of air through said casing, and means to alternately supply refrigerant to one and then the other of said cooling coils, a third .20 cooling coil interposed in said casing between said first mentioned cooling -coils and operatively connected by conduits containing heat exchange medium with a reheating coil positioned in the path -of the air emitting from said outlet.

2. An air conditioning apparatus comprising a casing with air inlet and outlet, means to move air therethrough, two cooling coils interposed in said casing in the path of said air, and means to reverse the flow of air through sai-d casing, and means to alternately supply refrigerant to one and then the other of said cooling coils, a third cooling coil interposed in said casing. between said first mentioned cooling coils and operatively connected by conduits containing heat exchange medium 3'5 with' a reheating coil positioned in the path of the air emitting from said outletmeans to change the direction of ilow of heat exchange medium through said third cooling coil responsive to the temperature of the air emitting from said outlet.

3. In an air conditioning apparatus comprising a casing with air inlet and outlet, means to move air through said casing and through a first coil and then through a second coil, said coils being spaced in said casing, means to reverse the direction of the flow of air through said casing and the first and second coil, and means to selectively .supply refrigerant to either one of said coils and on reversal of flow of air to cut olf the refrigerant to the coil lsupplied and supply refrigerant to the other of said coils.

4. In an air conditioning apparatus comprising a casing with air inlet and outlet, means to move air through said casing and through a first coil and then through a second coil, said coils being spaced in said casing, means to reverse the direction of the flow of air through said casing land the first and second coil, means to supply refrigerant to whichever of said coils is last in the path 'of said air and to cut off the supply of refrigerant to the coil first in the path of said air.

5. In an air conditioning apparatus comprising a casing with an Vair inlet and outlet vand two spaced coils therein and means to move air through' said casing and first through one coil and then through the other, means to reverse the flow of air and means to supply refrigerant to one of said coils and on reversal of flow of air to cut off the supply of refrigerant to the last named coil and supply refrigerant to the other coil.

6. In an air conditioning apparatus comprising a casing with an air inlet and outlet two spaced cooling coils in said casing, means to move air through said casing and successively through said coils and means to reverse the il'ow of said air, means to alternately supply refrigerant to first one and th'en the other of said cooling coils. both of said last two means being responsive to conditions indicating that one of said coils has become frosted.

7. In an air conditioning apparatus comprising a casing with an air inlet and outlet, and two spaced cooling means therein, means to move air through said casing and first through one cooling means and then through the other. means to reverse the flow of air, and means to supply cooling medium to one of said cooling means and on reversal of the flow of air to cut olf the supply of cooling medium to th'e last mentioned cooling means and supply cooling medium to the other said cooling means.

8. In an air conditioning apparatus comprising a casingwith an air inlet and outlet. two spaced coils therein, and means to move air through said casing and first through one of said coils and then through the other of said coils, means to selectively reverse the flow of air and means to supply refrigerant to one of said coils and on reversal of flow of air to out off' the supply of refrigerant to the last named coil and supply refrigerant to the other coil.

9. In an air conditioning apparatus comprising a casing with air inlet and outlet, means to move air through said casing and through a first coil and then through a second coil, said coils being spaced in said casing, means to reverse the direction of the flow of air through said casing and the first and second coil, means to supply refrigerant to whichever of said coils is last in the path of said air and to cut ofi' the supply of refrigerant to the coil first in the path of said air, both of said last two means being responsive to conditions indicating that one of said coils has become frosted.

10. In an air conditioning apparatus comprising a casing with air inlet and outlet, means to move air through said casing and through a first coil and then through a second coil, said coils being spaced in said casing, means to reverse the direction of the flow of air through said casing and the first and second coil, and means to selectively supply refrigerant to either one of said coils and on revers-al of ow of air to cut olf the refrigerant to the coil supplied and supply refrigerant to the other of said coils, both of said last two means being responsive to conditions indicating that one of said coils has become frosted. l

11. In an air conditioning apparatus comprising a casing with an air inlet and outlet and two spaced coils therein and means to move air through said casing and first through one coil and then through the other, means to reverse the flow of air and means to supply refrigerant to one of said coils and on reversal of flow of air to cut off the supply of refrigerant to the last named coil and supply refrigerant to the other coil, and a reheating coil positioned in the outlet of said casing to reheat the outgoing air after it has left the last of said cooling coils.

between said first mentioned cooling coils and operatively connected by conduits containing heat exchange medium with a reheating coil positioned in the path of air,emitting from said outlet.

.13. In an air conditioning apparatus comprising a casing with an air inlet and outlet and two spaced coils therein and means to move -air through said casing and first through one coil and then through the other, means to reverse the fiow of air and means to supply refrigerant to one of said coils and on reversal of flow of air to cut off the supply of refrigerant to the last named -coil and supply refrigerant to' the other coil, a

third cooling coil interposed in said casing between said rst mentioned cooling coils and operatively connected by conduits containing heat exchange medium with a reheating coil positioned in the ,path of the air emitting from said outlet and means to change the direction of flow of heat y to alternately supply refrigerant to one and then the other of said heat exchangers, a third heat exchanger interposed in said casing between said first mentioned heat exchangers, a reheat exchanger at the outlet of said casing in the path of air flowing through said outlet, conduits connecting said reheat exchanger and said third heat exchanger for circulation of heat exchange fluid therethrough.

15. An air conditioning apparatus comprising an elongated duct, two heat exchangers in said duct, an air valve having four openings therein, a first conduit connecting the first of said openings to one end of said duct, a second conduit connecting the second of said openings to the vother end of said duct, the third of said openings serving as an air supply opening, a third conduit connected to the fourth of said openings, said valve having movable means which in one position connects the rst and third openings and the second and fourth openings for passage of air and in another position connects the first and fourth openings and the second and third openings for passage of air, means to move air in,- wardly through said third opening and through said duct and`conduits, a third heat exchanger in said duct interposed between said two heat exchangers, and a fourth heat exchanger in said third conduit, means for circulating a heat exchange fluid between said third and fourth heat exchanger, and means for selectively supplying heat exchange medium to one of said first mentioned two heat exchangers.

NORMAN WEINSTEIN.

GERALD F. MANNION.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date y2,008,407 Stoever July 16, 1935 2,200,118 Miller May 7, 1940 2,215,327 Karsten Sept. 17, 1940