US3037364A - Air conditioning system - Google Patents

Description

June 5, 1962 c. TUCKER ET AL 3,037,364

AIR CONDITIONING SYSTEM Filed April 26, 1961 INVENTORS 12a Curl L. Tucker i e 38 BY Herbert L. Laube o 01. 52 M0; [/larrv'p, Wand; ATTORNEYS U d s P o" Patented June5, 1962 is air conditioned by a central refrigeration and ventilat- 3,037,364 ing system, it is inefiicient and overly expensive to AIR CONDITIONING SYSTEM Carl L. Tucker, dkaneateles, and Herbert L. Laube, Camillus, N.Y., assignors to Remington Corporation, Auburn, N.Y., a corporation of Delaware Filed Apr. 26, 1961, Ser. No. 105,685 11 Claims. (Cl. 62-158) This invention relates to air conditioning, and more I in particular to an air conditioning system for a building or for a part thereof which is divided into a number of rooms or other conditioned zones or spaces.

An object of this invention is to provide an air conditioning system for a multiple-space building or a part thereof. A further object is to provide an air conditioning system which is versatile and which may be operated efliciently to condition the air in the various rooms or spaces individually and without the operation in one room or space interfering with the operation elsewhere. A further object is to provide a cooling and ventilating system of the above character, wherein individual rooms or spaces may be cooled and ventilated as desired.

A further object is to provide a system of the above character where there is central control, and yet where the individual rooms may be cooled or ventilated independently of the central control. Another object is to provide an air conditioning system where the cooling and ventilating operations are performed by individual units within the various room and spaces and yet where a central control is provided which insures against unnecessary operation of the various units. A further object is to provide an air conditioning system comprising a number of individually controlled air conditioning units and a central control system therefor. A further object is to provide such a system which may have units added to it or taken from it without in any way interfering with the efficiency and operation of the other components of the system. These and other objects will be in part obvious and in part pointed out below.

In large office buildings and in multi-room living quarters, such as hotels, there is apt to be a wide variation in the needs and demands for air conditioning in the various rooms. The occupant of a room should be permitted to choose whether or not the air is to be cooled, or whether or not ventilation or air circulation is to be provided. For example, in an office building, one room or zone may be subjected to the effects of the sun or the outside wind, while another room or zone is not, so that one room or zone needs cooling while the other does not.

Furthermore, at the end of a working day, the occupants of some rooms or zones may leave while the others stay. Hence, in addition to the varying demands during the periods of occupancy, there are times when it is no longer necessary to cool certain rooms or zones; yet, the occupants are apt to neglect turning ofi the air conditioning units even though they are asked to do so.

Furthermore, it is often impractical to cheek constantly upon whether or not rooms are being occupied. The situation is more serious during holidays or over weekends when some of the people may be working while most of them are not. If a central control system is provided, the turning off of the system deprives all of the rooms or zones of the air conditioning facilities, and the few people who work are handicapped when they certainly should not be.

Similar problems exist with hotels and other quarters where air conditioning facilities must be provided for all of he rooms, but where occupancy of some rooms may be solely at night, while others are occupied in random fashion day and night.

When an ofiice building or a hotel, as referred to above,

operate the entire system for the purpose of air conditioning only one or a iew rooms. Hence, even it it were possible to maintain the system operating whenever it were needed by anyone, it would be quite objectionable to do so with most installations. It is the object of the present invention to provide an air conditioning system which avoids the difliculties referred to above, and which insures efficient, dependable, and thoroughly satisfactory operation under all conditions of demand and use.

In the drawing:

The single FIGURE is an abbreviated representation of an air conditioning system comprising one embodiment of the invention.

Referring to the drawing, the system is illustratively formed by a large number of identical self-contained units. However, for purposes of understanding the invention, it is necessary to illustrate only three of these units in the drawing and the showing has been limited in that manner to avoid unnecessary complications and repetition. The three air conditioning units 2, 4 and 6, which are shown, are located in different rooms of a building, and each of them is positioned at a window so as to use outside air for cooling and for ventilation, and so as to cool the room where the unit is located. These units receive electrical current through a pair of power lines 8 and it) which extend from a master control switch 12. The master control switch and the other components of the system which are shown, are represented schematically in the drawing, and it is understood that other equivalent switches and additional or other components are used in the actual commercial construction.

Air conditioning unit 2 has a refrigeration system or unit 11 which comprises a motor-compressor 1 4, a condense-r 1-6, a receiver 18, an expansion valve 20, and an evaporator 22. A fan 24, driven by a motor 26, directs air over the condenser, and a fan 28, driven by a motor 30, directs air over the evaporator. This entire refrigeration system and the controls are enclosed within a casing indicated in broken lines at 32. As has been stated above, the unit is positioned at a window or an opening in the outside wall so that outside air is drawn in by the fans for ventilation of the room and for cooling the compressor and the condenser, and fan 28 circulates the air over the evaporator for cooling the room. The circulation of air by fan 28 involves a substantial amount of recirculation of the air in the room, but fresh air is drawn in as desired. An airfilter is provided for the air passing through the evaporator, and other components and controls are provided as desired.

Air conditioning unit 2 includes internal power lines 36 and 38 to which power is supplied to operate the unit through a manual control switch 34, in a manner discussed below. These lines are connected to the motor compressor 14, and to the fan motors 26 and 30. Hence, when the power lines 10 and 8 are connected respectively 10 lines 36 and 38, the air conditioning unit is operated.

The control system for unit 2 includes the following components: the manual control switch 34 formed by a pair of switch untis 31 and 33 which are closed when the occupant of the room or the operator desires that the unit be operated; a normally open push button switch 44 which is closed momentarily to restart the unit when it has been stopped remotely in the manner discussed below; a relay 46 which acts to start and stop the unit when switch 64 is in its closed position; and a double-acting switch 42 which prevents automatic closing of relay 46, as will 'be discussed below. i Switch 42 has a bimetallic strip '50 which is positioned 'as shown when it is at room temperature, but which moves to the broken-line position when it is heated. A heater 52 is connected directly across lines 8 and 10 so that it becomes heated whenever power is supplied to these lines. Switch 42 has a pair of movable contacts 54 and 56 mounted upon flexible arms and adapted to be together when both arms are at rest. However, when the bimetallic strip 50 is at room temperature, it moves contact 54 to the full-line position away from contact 56, and when the bimetallic strip is fully heated, it moves contact 56 to the broken-line position away from the contact 54. Also, when strip t moves between these extreme positions, it moves through a central position wherein it is out of contact with both of the contact arms so that the contacts are together and switch 42 is closed. Assume that heater 52 is not energized and bimetallic 5t] strip is in its full-line position, so that contact 54 is held away from contact 56 and switch 42 is open. Thereafter, when heater 52 is energized, the initial heating of the bimetallic strip causes it to straighten to the intermediate position wherein it is out of engagement with both contact arms, so that contact 54 has moved against contact 56, and switch 42 has closed. The continued heating of the bimetallic strip causes it to swing to the broken-line position and, in doing so, it moves contact 56 away from contact 54, thus re-opening switch 42. As will be discussed more fully below, switch 42 introduces time delay characteristics in the operation of the system.

Relay 46 has a solenoid 40 and a pair of normally open switches 41 and 43, both of which have their armatures connected to line 8. Solenoid 40 is connected at one side to line 10, and at the other side to the fixed contact of switch 41 and also through a line 51 to one contact of the push-button switch 44 and to contact 56 of switch 42. The other contact 54 of switch 42 is connected to line 8. The fixed contact of switch 43 of relay 46 is connected to switch unit 33 of switch 34, and the other switch unit 31 of switch 34 is connected to line 10.

It will now be assumed that the master control switch 12 has been open for an extended period of time, and that the various components of the circuit are positioned as represented in the drawing, with switch 34 closed and the bimetallic strip 50 at room temperature so that contact 54 is held to the left and switch 42 is open. If switch 12 is then closed, line is connected through switch unit 31 to the compressor and fan motors of unit 2, but the motors do not operate, because switch 43 of relay 46 is open so that line 8 is not connected to switch unit 33. However, energization of lines 8 and 10 is effective immediately to energize heater 52. This causes the bimetallic strip to start moving toward its intermediate position so that contact 54 moves against contact 56 to close switch 42. This completes a circuit from line 8 through switch 42 and line 51 to solenoid 40, thus energizing the solenoid. The energization of solenoid 40 closes switch 43 so as to connect line 8 through switch unit 33 to the compressor and fan motors, and the unit starts operation. The energization of solenoid 40 also closes switch 41 so as to connect line 8 directly to solenoid 40 and lock-in the relay. Therefore, solenoid 40 remains energized, and unit 2 continues to operate even after the original energizing circuit of the solenoid has been broken by the opening of switch 42 when strip 50 moves to the brokenline position.

The operator or occupant of the room may stop the operation of unit 2 by opening switch 34, and the invention contemplates that unit 2 may be provided with automatic controls. However, the opening of switch 34 does not de-energize solenoid 40, and unit 2 may be restarted by reclosing switch 34. At the end of the day or at any other time, the engineer or the other operating personnel for the entire building may stop the operation of all of the air conditioning units by opening switch 12.

The invention contemplates that it is desirable at times to stop all of the air conditioning units, but to permit the occupants of the various rooms or zones to restart the various units individually. For example, as discussed above, most of the occupants of an office building may leave the premises at the end of the working day, but it is desirable to permit the remaining occupants to start their air conditioning units if they wish. Under such circumstances, switch 12 is opened, and then reclosed immediately. The opening of switch 12 de-energizes each of the solenoids 40 so that the switches of relays 46 are all opened, and all of the air conditioning units are stopped. Also, at each unit, the momentarily de-energizing of the heater 52 does not permit the bimetallic strip 50 to cool appreciably, and therefore the bimetallic strip remains in the broken line position so that it continues to hold the contact 56 away from the contact 54, and the switch 42 remains open. Therefore, the reclosing of switch 12 does not re-energize the various solenoids 40, and the air conditioning units are not started automatically. However, the air conditioning unit in any room or zone may be started by pressing the push-button switch 44. The closing of switch 44 completes a circuit from line 8 through switch 44 and line 51 to solenoid 40, and this closes relay 46 and starts the unit. The energization of relay 46 closes the hold-in switch 41 so as to maintain solenoid 40 energized and continue the operation of the air conditioning unit. It is thus seen that after the system has been operated continuously, the momentary opening of switch 12 will stop all of the air conditioning units, but that any of the units may be restarted immediately or at a later time, and then will continue to be operable as long as switch 12 remains closed. If the occupant of a particular room or zone desires to do so, he may open his switch 34 and stop his unit at any time.

With the system herein disclosed, after switch 12 has been open for a sufficient period of time for the bimetallic strips 50 to cool, the closing of switch 12 starts all of the air conditioning units which have their switches 34 closed. Hence, in a building where it is desirable to start all of the air conditioning units at the beginning of the day, the switches 34 of all of the units are kept closed so that the units are started by the closing of switch 12. However, with a hotel or another building where it is desirable to start only certain of the air conditioning units, the switches 34 for the other units are opened, and the closing of switch 12 starts only the desired units.

The illustrative embodiment of the present invention has an additional important feature, namely, the random or staggered starting of the various air conditioning units after they have all been shut down for a period of time. The staggered starting of the units distributes the peak starting current loads over a sufficient time to prevent overloading of the electrical circuit, but these peak current loads are of very short duration, and the staggered starting does not make any perceptible change in the time of starting the various air conditioning units. Nevertheless, very substantial benefits are derived, as compared with a system where all of the starting switches would be closed at exactly the same instant. It has been pointed out that each of the air conditioning units is started only after the bimetallic strip 50 in its switch 42 has moved from the rest position to its intermediate position wherein contacts 54 and 56 come together. Hence, to obtain staggered or sequential starting of the various air conditioning units, the various switches 42 in the system are given slightly different adjustments or operating time characteristics so that the switches 42 do not close simultaneously. As a practical matter, the manufacturing tolerances for such switches may be such that the switches do not need to be adjusted specifically to give staggered starting of the various units. However, where desirable, the time delay in the closing of the various switches 42 can be adjusted so that the units are started in predetermined pattern.

The present invention contemplates the momentary disconnecting of the electrical power to the system so as to stop the various units of the system, and it has been indicated that this can be done manually at selected times. The invention also contemplates that this power disconnecting operation may be carried on automatically, for example, by a program switch unit. Accordingly, in the drawing, master control switch 12 is of the solenoid type, with a solenoid 124, and a manual switch 127 which is closed to energize the solenoid in closed switch 12 manually. However, in order to provide automatic operation, solenoid 124 includes a normally opened push-button switch 126, and a normally closed push-button switch 128. The closing of switch 12 connects lines 8 and 10 respectively to power lines 130 and 132. Solenoid 124 is connected at one side to line 132, and the closing of switch 126 connects the other side of the solenoid to line 13:). An interlock circuit to solenoid 124 is also provided by a line 134 which extends from line 8 through the normally closed switch 128 to solenoid 124. Switch 12 is normally urged toward its open position by a spring 136. A normally closed switch 125 in series with switch 126 may be opened to disconnect the automatic program circuit.

The momentary closing of push-button switch 126 energizes solenoid 124, and closes the master control switch 12. The switch is then held closed by the interlock circuit formed by switch 128 and line 134. The opening of switch 128 breaks the interlock circuit and de-energizes solenoid 124, and switch 12 reopens auto matically. Connected across lines 130 and 132 is an adjustable timer 138 which has a cam shaft upon which two cams 140 and 142 are mounted. When the cam shaft is rotated by timer 138, cam 142 first moves into engagement with switch 123 and opens this switch, and then after a short interval of time cam 141i moves against and closes switch 126. Hence, one complete revolution of the cam shaft opens the master control switch 12 and then recloses it after a predetermined period of time. This period of time is sufficient to permit the relays 46 for the various air conditioning units to be opened.

Timer 138 may be adjusted to turn its cam shaft 21 complete revolution at the end of any predetermined period of time, or at predetermined intervals in accordance with a program. Therefore, with the timer operating continuously, the camshaft remains stationary except at the pro-selected times of the day when it is determined that the power circuit should be opened. For example, with the arrangements discussed above, the suggested manual opening and closing operations of the master control switches are performed in accordance with a predetermined setting of timer 138. This may include the opening of switch 12 at 8 p.m., and at every four hours thereafter as long as the building is occupied during the evening and over week-ends.

It will be understood that the invention is applicable to systems other than the one represented in the drawing, and particularly to systems incorporating additional features and characteristics. In the illustrative embodiment, the refrigeration means at each zone or room is a self-contained unit, but it is understood that other refrigeration means, such as chilled water coils and fancoil units, may be used while still attaining certain advantages of the invention. The power supply and control circuit provides remote control for the basic operation, and yet permits the occupants to exert control upon the individual air conditioning units. Also, thermostatic controls may be included, particularly where manual control may not be fully satisfactory.

As many possible embodiments may be made of the mechanical features of the above invention and as the art herein described might be varied in various parts, all without departing from the scope of the invention, it is to be understood that all matter hereinabove set forth, or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

We claim:

1. In an air conditioning system for maintaining desired conditions within various zones of a building, the combination of, a plurality of individually operable air conditioning units positioned respectively at zones to be conditioned and each including refrigeration means to cool air, a plurality of separate individual control assemblies associated respectively with said units to control the starting and stopping of the operation of said units independently of each other, each of said control assemblies comprising a relay switch which is energized to complete a circuit from power supply lines to the unit and a time-delay switch connected to be operable to energize said relay switch, said time-delay switch comprising a switch formed by a pair of movable contacts and a contact-moving element which holds said contacts separated when said element is in its rest position and which moves through a cycle wherein the contacts are moved together and then separated.

2. An air conditioning system as described in claim 1, wherein said operating element of said time-delay switch is a bimetallic strip which holds one of said contacts from the other when in its rest position, and which moves the other contact away when in its fully heated position, and a heating element which is adapted to heat said bimetallic strip.

3. An air conditioning system as described in claim 2, wherein said heater element for each of said control assemblies is connected directly across the pair of lines supplying power to its air conditioning unit, and wherein all of said air conditioning units are supplied with power to their respective control assemblies simultaneously and wherein said relay switches are closed in sequence under the immediate control of the respective time-delay switches.

4-. In an air conditioning system, the combination of a plurality of self-contained air conditioning units, means constituting a supply power to operate said units, and control means to control the supplying of power to said units individually comprising a plurality of starting switches and a plurality of time-delay switches, each of said time-delay switches being connected to operate one of said starting switches after a predetermined time delay following the energization thereof, said time-delay switches being constructed and arranged to have different operating time characteristics whereby said starting switches are operated in a staggered relationship.

5. In an air conditioning system as described in claim 4, wherein each of said starting switches comprises a switch and a bimetallic operating element which is adapted when unheated and when fully heated to hold such switch open and which is adapted to close said switch during the period when its temperature is being increased.

6. An air conditioning system as described in claim 5, wherein each of said starting switches comprises switch means and a solenoid which is energized to close said switch means, said solenoid being connected in series with its time-delay switch.

7. Apparatus as described in claim 6, wherein said switch means of said starting switch comprises a main power switch and a hold-in switch, said hold-in switch being connected to hold said solenoid energized even though the original energizing circuit has been disconnected.

8. A system as described in claim 7 which includes a normally open manual switch in parallel with said timedelay switch.

9. In an air conditioning system for maintaining various zones of a building at individually selected temperatures, the combination of, a plurality of separate air-conditioning units, means constituting a common power supply for said units, and a control system comprising a master switch for said power supply and a plurality of switch assemblies associated respectively with said units each of said switch assemblies comprising a unit-control switch and switch means to control the closing of said unit-control switch, said switch means comprising a time-delay switch and a manual switch in parallel, said time-delay switch being adapted to close and open after being energized following a period of being de-energized.

10. In an air conditioning ystem for maintaining the desired temperatures throughout a building, the combination of, a plurality of separate units each of which is operable to change the air temperature flowing through it, and a power supply and control system comprising means constituting a supply of power for said units and to conmeet and disconnect said supply, said power supply and control system including a plurality of control assemblies associated respectively with said units and each including unit-control switch means which is opened and closed to stop and start its unit when power is supplied thereto and a timer operating unit which is operable upon the initial supplying of power to the unit to close its unitcontrol switch means, each of said control assemblies being constructed and arranged to open its unit-control switch upon each discontinuance of the supplying of power thereto and being inoperable to reclose its unitcontrol switch except when the power supply has been discontinued for more than a predetermined period of time, each of said control assemblies also including an auxiliary switch which is operable to close its unit control switch.

11. A system as described in claim 10, wherein said timer-operating unit for closing said unit-control switch comprises a switch assembly including heating means and temperature responsive switch-operating means which opens the circuit when at ambient temperature and fully heated and which completes the circuit during the period when being heated.

References Cited in the file of this patent UNITED STATES PATENTS 2,048,711 Ridge July 28, 1936 2,053,945 Cowin Sept. 8, 1936 2,145,298 Eisinger Jan. 31, 1939 2,200,215 Lewis May 7, 1940

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