US2124932A - Air conditioning system - Google Patents

Description

July 26, 1938. I w. E. STARK ET AL 2,124,932

AIR CONDITIONING SYSTEM Filed Jan. 6, 1936 v 2 Sheets-Sheet 1 ATTORNEYE July 26, 1938.

w. E". STARK ET AL AIR CONDITIONING SYSTEM Filed Jan. 6, 1936 2 Sheets-Sheet 2 INVENTOR.

BY JAMES 68477-57730 A nfifi Patented July 26, 1938 Am conmrromc SYSTEM Willet E. Stark, East Cleveland, and James 0. Patterson, Shaker Heights, Ohio, asslgnors to The Bryant Heater Company, Cleveland, Ohio,

a corporation of Ohio Application January 6, 1936, Serial No. 57,668

11 Claims.

This invention relates to improvements in air conditioning systems, particularly systems employed in localities or climates where the principal requirement is for dehumidification with more or less cooling, and where heating requirements are infrequent, relatively small and of comparatively short duration.

One of the objects of the invention is the utilization of a dehumidifier as a means for heating the premises,

Another object is the provision of an air conditioning system which will respond quickly and automatically to changes in atmospheric conditions, and particularly to a system in which the small amount of occasional heating that is needed is accomplished by the same equipment that is ordinarily used for dehumidifying without in any way changing the operation of that equipment.

Another object is the provision of means for controlling automatically the operation of a dehumidifier of the adsorption type and associated apparatus, so as to cause the same to supply dry air cooled to room temperature when the temperature in the premises is high enough for comfort, or dry heated air when the temperature is below the desired standard, th'e heat being principally heat of vaporization converted into sensible heat by the dehumidifier.

A further object is the provision of means for utilizing heat resulting from the dehumidifylng action and the reactivation process to heat water, or to perform other useful work.

Other objects and features of novelty will appear as we proceed with the description of that embodiment of the invention which, for the purposes of the present application, we have illustrated in the accompanying drawings, in which Fig. 1 is a diagrammatic view of an air conditioning system employing a dehumidifier of the adsorption type and embodying the present invention.

Fig. 2 is a wiring diagram showing control circuits for the apparatus, and

Fig.3 is a detail elevational view of a humidostat which may be used in connection with the invention.

The air conditioning system comprehended by this invention is designed to take care of all consuch character that heat is released in the proc-' ess of dehumidification, so that the air passing through the dehumidifier emerges in a warm state. For this purpose we prefer to employ a dehumidifier oi the adsorption type employing a solid adsorbent, such for instance as silica gel. Certain liquids, such as lithium chloride and calcium chloride may be used, instead of solid material if desired, the thermal changesv taking place being of practically the same value. In the latter case the action is chemical rather than physical, and hence it is not strictly proper to refer to such a dehumidifier as of the absorption type, but it is to be understood that these two forms of dehtunidifier are equivalent for the purposes of the present application.

Referring particularly to the action of a dehumidifier using silica gel, when air containing water vapor is brought into contact with the silica gel the water vapor is in effect condensed within the pores of the gel. This results in the liberation of the latent heat of the water vapor removed, so that the air issues from the gel dried, but with its sensible heat increased by an amount equal to the latent heat of the moisture removed, this being approximately 1,100 B. t. u. per pound of water vapor removed. In addition the heat of adsorption is liberated and goes to heat the air, this being of the order of 200 B. t. u. per pound of water vapor. In conventional dehumidifica tion apparatus of this type this latent heat (transformed into sensible heat) is removed by passing the dried air over coils containing cooled water. However, if the air is not cooled after being dehumidified, but is discharged dry and hot into a given space, it will warm that space as well as lower its humidity. When using a dehumidifier of the adsorbent type in the usual manner, even more heat than is above indicated is in effect available for use. In practice, in a dehumidifier there are two or more bodies or beds of silica gel. While one of these beds is drying air, the other is itself being dried by the application of heat, as by passing through it a mixture of air and the products of combustion of a gas fire, suflicient air being used to give a mixture temperature of about 4 350. This process is called reactivation. At its conclusion the gel will be rather warm, and when it is again used to adsorb moisture, some of this heat in the gel will be imparted to the air. In the'actuai dehumidification the dried air leav- 112% the apparatus is at a temperature of about F. Referring to Fig. 1 of the drawings, l0 indicates a room or space which is to beair conditioned. Fresh air in suflicient amounts to meet the ventilation needs of the space is drawn in through duct II by the action of a fan i2 mounted at the entrance to a dehumidifier l3. The dried air leaving the dehumidifier passes by way of a conductor |4 through an air cooler l5 in which is located a radiator, indicated diagrammatically at l6. In our system the cooler l5 may or may not operate, depending upon the temperature conditions in the space In. The air delivered from the cooler l5 enters a mixing'chamber I1, where it is mixed with a larger stream of recirculated air being drawn by a fan |8 through duct l9 from the space H), and discharged back into the space through a duct 28. Immediately following mixing chamber -|1 is an air cooler 2|, in

-which there is located another radiator 22 through which we may cause to flow cool water or any available refrigerant. If desired, a heater 23 supplied with fuel through a pipe 24 may be placed in the duct following air cooler 2| for a purpose later to be described. This heater may be of any appropriate type, such as a gas heater indicated in the drawiiigs, or a steam or hot water coil. Cooler l5 will usually be supplied with water from city mains or a well through pipe 25.

Returning now to the dehumidifier l3, which is shown diagrammatically, there are silica gel beds 26 and 21 which are used alternately as air driers. 28,28, 30 and 3| are four swinging deflectors or valves which are caused to take the full line and dotted line positions alternately at regular intervals while the dehumidifier is in operation. The conduit l4 connects with the right side of the dehumidifier through an opening 32. A similar opening 33 in the left side connects with a conduit 34 in which is located a fan 35. A gas burner 38 fed by a fuel line 31 produces a flow of hot air and gas of a temperature approximating 350 F. upwardly through conduit 38 into the dehumidifier casing. This heated air and gas is the reactivating medium, and the conductor 34 is the exhaust pipe for that medium. It may include an enlarged section 39 in which is located a radiator 40 by means of which some of the heat of the exhausted reactivated medium may be absorbed.

When the valves of the dehumidifier are in the full line position fresh air is caused to flow through silica gel bed 26, by which it is dried, and then out through opening 32 and conduit l4, as indicated by the arrows; At the same time hot reactivating medium flows in the opposite direction through the lower part of the casing and through gel bed 21, driving out the moisture previously adsorbed by that bed, and passes out through opening 33 and conductor 34, the fan 35 assuring the flow. When this has continued for a predetermined length of time the valves are automatically thrown to the dotted line position, whereupon the fresh air flows toward the right through gel bed 21 and out to the recirculating system, while the hot air for reactivation flows toward the left through gel bed 25 and out through opening 33 and conductor 34.

In fuel pipe 31 we locate an electric valve 4|. A similar valve 42 is used in pipe 25 leading to radiator It. From that radiator there extends a pipe 43 in which'there is a hand valve 44 which, when opened, permits the cooling water flowing through the pipe to pass to the drain.

Another pipe 45 in which there is a hand valve 46 connects with pipe 43 and with radiator 48, so that when the valve 44 is closed and the valve 46 opened the warm water from radiator I6 is it is further heated and then carried by pipe 41 to a suitable storage tank 48, from which it may be drawn for use directly or for still further heating, as may be required.

The radiator 22 is fed by a pipe 49 having an electric valve 58 therein, and the cooling medium delivered from the radiator is discharged to the drain or otherwise through a pipe 5|. Another electric valve 5| controls the flow of fuel to the heater 23.

The instruments by means of which the system is automatically controlled may be located as found desirable or convenient either in the space ID or in a conductor forming part of the path for the recirculated air. In the drawing they are shown in the conduit l8. They consist of a humidostat 52 and three thermostats 53, 54 and 55.- These instruments may be of conventional form. An example of 'a humidostat which is suitable for the purpose is illustrated however in Fig. 3, where 56 is a tape which expands and contracts as the humidity of the air in contact with itincreases or decreases. This tape is secured at one end in an adjustable anchoring means 51, and at the other end in a lever 58 pivotally mounted at 59. 60 and 8| are flexible electrical conductors which have terminals in a mercury tube switch 52 which is tiltably mounted at 63 and is adapted to be swung to circuit closing position by the action of a spring 64 when the tape 56 expands to a predetermined extent due to a rise in humidity, and

to a circuit opening position by the contraction of tape 58 when the humidity falls sufficiently. Terminals 55 and 66 of the humidostat are connected by electrical conductors 61 and 68 into the control system, as will presently be described.

A duct 63 may be provided with connections as shown if it is desired to direct some recirculated air to the dehumidifier during periods of extreme outdoor moisture, so as to lighten the load 0 the dehumidifier.

Referring to Fig. 2, two electric service wires are indicated at 18 and 1|. Connected to these wires are two conductors 12 and", forming a circuit to supply energy to the primary coil 14 of a step-down transformer. The-secondary coil 15 forms a part of a low voltage circuit including conductors 16 and 11 across which the conductors 61 and 68 are bridged. In this same circuit there is an electromagnet 18 controlling a switch 18 which is adapted to open or close a circuit comprising conductors and 8| and a motor 82. The motor 82 is the dehumidifier motor which operates the fans l2 and 35, and by means of cams or other suitable mechanism shifts valves 28, 29, 38 and 3|- back and forth at regular intervals between their full line and dotted line positions, respectively. Branch conductors 83 and 84 serve to energize a magnet coil 85, which opens gas valve 4|. Other branch conductors 86 and 81 lead to an electromagnet 88 which controls a switch 89 to which we will refer again later.

Bridged across the low voltage conductors 18 and 11 in a line parallel with the line through humidostat 52 are two conductors 98 and 8| which are adapted to be connected together by thermostat 54 when the temperature in the premises falls to or below a predetermined point. It will be apparent therefore that the dehumidifier isarranged to be started either by the humidostat or bythe thermostat 54, and that it will operate if the temperature becomes low enough,

whether or not the humidity conditions are such as would cause the humidostat to function.

The thermostat 54 is a double contact thermostat, one contact 92 being the terminus of conductor 9i and the other contact 93 being connected with a low voltage conductor 94 which extends to one side of switch 89. From the conductor a conductor 95 extends to the secondary coil 96 of a step-down transformer, the primary coil 91 of which takescurrent from the line wires 10 and Ii through conductors 98 and 99. The other side of coil 96 is connected by means of a conductor I00 with an electromagnet BM controlling the valve 42 in the cooling water line 25. Magnet I0! is also connected by a conductor I02 with the other side of switch 89. It will be apparent therefore that when the thermostat 54 moves to the right because of rising temperature, and engages contact 93, a current willbe set up through electromagnet it! provided that switch 89 is closed at the time. But the switch 89 is closed only when switch 19 is closed and the dehumidifier is in operation. Two conditions are therefore necessary before cooling water will flow through pipe 25, first the dehumidifier must be in operation, and second the temperature in the premises must be above a predetermined point. In somelocalities where the heat requirements are small, heater 23 may be omitted. When it is used the valve 5| is controlled by an electromagnet I03 which is connected on one side by a conductor M with line wire Ill, and on the other side by a conductor N35 with a contact Wt adapted to be closed by thermostat 55 when the temperature in the premises falls below a predetermined point, the other side of the thermostat being connected by a conductor IM with line wire I l. Through the pipes 49 and iii any suitable refrigerant may be conducted to and away from radiator 22. The functioning of this radiator is controlled by valve 50, which may be opened electrically by a magnet it which is in circuit with line wire H through a conductor W9 and with line wire it through conductors Mil and ill and the thermostat 53. When the room temperature rises above a predetermined point the thermostat 53 engages its contact M2, whereupon electromagnet tilt is energized and the valve 50 is opened permitting refrigerant to flow through the radiator.

By the proper selection or adjustment of the thermostatic control devices the range of action of the heater 23 and of the two cooling radiators l6 and 22 can be regulated to suit requirements. We prefer to so select and adjust the parts that the heater 23 will be turned on only when a relatively low temperature is reached in the premises, and will be turned ofi slightly before the desired temperature is attained. We also prefer to have the radiator l6 function normally as an intermediate range cooler for the dried air issuing from the dehumidifier, which cooler will be turned off automatically when small increases in temperature are called for. The radiator 22 in which refrigerant circulates we prefer to call into play only when the temperature is relatively high, that is, such that the radiator I6 is not able by itself to accomplish the desired result.

Variations from the described structure may be employed. Accordingly, we desire it to be understood that the scope of the invention is to be regarded as defined exclusively by the appended claims rather than by the foregoing description or the accompanying illustration.

Having thus described our invention, we claim:

1. In an air conditioning system, means for recirculating air,'a dehumidifier of the adsorption type arranged to deliver air into said recirculating system, a cooling means for the air delivered by the dehumidifier, and thermostatic means responsive to temperature changes only for controlling said dehumidifier and said cooling means,

acting to cut off the cooling means whereby the when the temperature falls to a lower predetermined level. I

3. In an air conditioning system, means for recirculating air, a dehumidifier of the adsorption type arranged to deliver air to said system, means for heating the recirculating air, and

thermostatic means responsive to temperature changes only for starting said dehumidifier when the temperature in the premises falls to a predetermined level and for starting said air heating means when the temperature falls to a lower predetermined level.

4. In an air conditioning system, means for recirculating air, a dehumidifier of the adsorption type arranged to deliver air to said system, a heater and a cooler for the recirculating air, and thermostatic means responsive to temperature changes only for disabling said cooler when the temperature in the premises falls to a predetermined level, for starting said dehumidifier when the temperature falls to a lower predetermined level, and for-starting said air heater when the temperature falls to a still lower predetermined level.

5. In an air conditioning system, means for recirculating air, a dehumidifier of the adsorption type arranged to deliver air to said system, a humidostat and a thermostat arranged in parallel for causing said dehumidifier to function, not only when the humidity in the premises is high, but also whenlthe temperature in the premises is low irrespective of the humidity.

6. In an air conditioning system, means for recirculating air, a dehumidifier of the adsorption type arranged to deliver air to said system, a cooler for the air delivered by the dehumidifier, a humidostat adapted to start said dehumidifier when the humidity in the system rises to a pre determined percentage, and a thermostat acting in conjunction with said humidostat for controlling said cooling means adapted to set it in operation only when the dehumidifier is in operation and the temperature of the premises is at or above a predetermined point.

7.. In an air conditioning system, means for recirculating air, a dehumidifier of the adsorptiontype arranged to deliver air tosaid system, a cooler for the air delivered by the dehumidifier, and a double electrical control for said cooler, one element of said control opening and closing with the starting and stopping of the d ehumidifier and the other element closing and opening with the rise and fall of the temperature in the premises with respect to a predetermined temperature level.

iii)

8. In a control system for air conditioning means, a.dehumidifier, a control circuit therefor, two parallel lines bridged across said control circuit, each of said parallel lines having switches, a humidostat adapted to close one of said switches when the humidity rises above apredetermined point, and a thermostat adapted to close the other switch when the temperature falls below a predetermined point.

9. In an air conditioning system, means for recirculating air, a dehumidifier of the adsorption type arranged to deliver air into said recirculating system, a cooling means for the air delivered by the dehumidifier, humidity responsive means for controlling said dehumidifier, and thermostatic means for controlling said dehumidifier and said cooling means, said thermostatic means acting to start the dehumidifier and ,to prevent the cooling means from operating when the temperature of the system falls below a predetermined point, regardless of the condition of the humidity responsive means.

10. In an air conditioning system, means for recirculating air, a first cooling means for cooling said air, thermostatic means for starting said first cooling means at a relatively high temperature and stopping it at a slightly lower temperature, a dehumidifier of the adsorption type arranged to deliver air to said recirculating system, a second cooling means for the air delivered by said dehumidifier connected to operate only when the dehumidifier is operating, a humidity responsive device to startand stop said dehumidifier and second cooling means at predetermined relative humidities in the system, thermostatic means for disabling said second cooling means at a predetermined low temperature and for setting it in operation at a slightly higher temperature, and for starting said dehumidifier and holding said second cooling means disabled-at said predetermined low temperature regardless of the condition of the humidity responsive device and for stopping it at a slightly higher temperature.

11. In an air conditioning system, means for recirculating air, a first cooling means for cooling said air, means for heating said air, thermostatic means for starting said first cooling means at a relatively high temperature and stopping it at a slightly lower temperature, thermostatic means for starting said heating means at a relatively low temperature and stopping it at a slightly higher temperature, a dehumidifier of the adsorption type arranged to deliver air into said recirculating system, a second cooling means for the air delivered by said dehumidifier connected to operate only when the dehumidifier is operating, a humidity responsive device to start and stop said dehumidifier and second cooling means at predetermined relative humidities in the system, intermediate temperature thermostatic means which will disable said second cooling means at a predetermined intermediate temperature and will cause it to operate at a slightly higher intermediate temperature, and which will JAMES c. PATTERSON. WlLLET E. STARK.

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