US2091563A - Air conditioning system utilizing refrigeration - Google Patents

Description

Aug. 31, 1937.

ELEc'rKI SOURCE R. 'r. PALMER 2,091,563 AIR CONDITIONING SYSTEM UTILIZING REFRIGERATION Filed March 15, 1936 3 Sheets-Sheet l MIXING CHAMBER ELECTRIC sauce:

MIXING- CHAMBER Fl LTEZ Aug. 31, 1937. R T, PALMER 2,091,563

AIR CONDITIONING SYSTEM UTILIZING REFRIGERATION Filed March 13, 1936 3 Sheets-Sheet 2 ELECTRIC SouzcE CHAMBER E LECTIZIO Sou BCE REFRIGERATION SUPPLY Aug. 31, 1937. R. T. PALMER AIR CONDfTIONING SYSTEM UTILIZING REFRIGERATION s Sheets-Sheet 13;

Filed March 13, 1936 for Mun

NOWWWNL Hp uowwwumtoo ZOO UUNDOW Q- NPOWAU muzwoqozm NNLIZDOO Patented Aug. 31, 1937 UNITED STATES PATENT OFFICE AIR CONDITIONING SYSTEM UTILIZING REFRIGERATION Robert T. Palmer, Sharon, Mass, assignor to B. F. Sturtevant Company, Inc., Boston, Mass.

Application March 13, 1936, Serial No. 68,657

15 Claims.

space within which the conditioned air is supplied.

According to this invention, the air volume, and the refrigerating energy is varied in accord- 15 ance with the number of people in the space supplied with conditioned air. In one embodiment of the invention, a plurality of cooling coils extend, in the conditioner, cross-Wise the air stream, and the number of the active coils is. varied in accord- 20 ance with load conditions. The inactive coils are shunted out of the air flow to reduce the resistance of the air through the conditioner, and the air volume is reduced.

In one embodiment of the invention, the con- 25 trols of the air conditioning system are adjusted in accordance with the number of persons in the enclosure as determined by an actual count.

An object of the invention is to condition air at minimum expense.

30 Another object of the invention is to efficiently save fan power and refrigerating energy in an air conditioning system, when the load is reduced.

Another obejct of the invention is to adjust the controls of an air conditioning system supplying 35 air to an enclosure, in accordance with the number of persons in the enclosure as determined by actual count.

Other objects of the invention will be apparent from. the following description taken together 40 with the drawings.

The invention will now be described with reference to the drawings, of which:

' Fig. 1 is a diagrammatic view of one embodiment of the invention utilizing several groups of a cooling coils in the conditioner; each group of coils being served by a separate source of refrigeration;

Fig. 2 is a diagrammatic view of another em- 50 bodiment of the invention in which all groups of air cooling coils are supplied by a single source of refrigeration; and

Fig. 3 is a diagrammatic view ofanother embodiment of the invention in which controls are varied by a device which counts the actual number of persons in the space served with conditioned air.

With reference to Fig. 1, there is illustrated what is known as a by-pass system of the general type shown by the Patent No. 1,670,656 to W. L. 5

Fleisher. In the present case, the conditioner 5 has mounted therein, cross-wise the air stream, the three groups of evaporator coils, 6, l and 8. The coils.6 are supplied through the expansion valve 9 with any suitable refrigerant from com- 10 pressor #i and condenser #I. The coils I are likewise supplied from compressor #2 and condenser #2, through valve 50, and the coils 8 are supplied through valve l I from compressor #3 and condenser #3. In front of, with respect to air how, of the coils 6, are the shutters l2 adjusted to open or closed position by the motor I3. Similar shutters l4 adjusted by motor l5 are before the coils I, and similar shutters I6 adjusted by motor ll are before the coils 8.

The thermostat i8 is mounted in the path of the mixed recirculated and outside air leaving the mixing chamber IS. The recirculated air from the enclosure 20 enters the mixing chamber I9 through the duct 2|, and the outside air after '5 passing through the filter 22, enters the mixing chamber is through the duct 23.

The control thermostat I8 is seen to be responsive to the condition of the air to be conditioned.

In the past, it has been customary to place such control thermostats in the space being conditioned or in the recirculated air duct, on the theory that the load offered by the outdoor air is constant while the load within the space fluctuates to a great extent. In many cases, however, the load ofiered by the outside air has been found to fluctuate while the load offered by the recirculated air remains substantially constant so that it is preferred to so mount the control thermostat is that it responds to the changes in load of the total air entering the conditioner.

The thermostat i8 upon a decrease in the temperature of the air entering the conditioner 5, indicating that less refrigeration is required, acts first to open theenergizing circuit of the shutter control motor ll, causing it to close its associated shutters IS in front of tthe coils 8, as shown by the drawings. The suction temperature of the refrigerant entering the compressor #3 through the thermo-responsive valve 24, then falls, causing the thermostatic element within the valve 25 to open the circuit including the motor 25, the solenoid 26, the wires .21, 28 and 29, causing the compressor #3 to shut down.

At the same time, due to the deenergization of the solenoid 28, its armature falls to open a circuit including the fan driving motor 3|, the

wires 32 and 33, the contact 34, and an electric source disconnecting the motor 3| from across 5 the line leading to the electric source. The

armature 38 then closes an electric circuit including the electric source, the contact 35, the armature 36, the contact 31, the resistor 38 and the fan motor 3|, thus connecting the fan motor in series with the resistor 38 to the electric source, causing the speed of the fan 39 and the air volume it delivers, to be reduced. The fan then acts to draw a reduced volume of mixed recirculated and outside air through the active coils and 8, the inactive coils 8 offering no re-' sistance to the air flow.

If this reduction of cooling surface and air volume is not sufficient, the thermostat 8 next acts to open the energizing circuit of the shutter control motor l5, causing it to close its associated shutters l6 in front of the coils l. The temperature of the refrigerant entering the compressor #2 then falls causing the thermo-responsive valve 48 to open a circuit including the compressor driving motor 4|, the solenoid 42 and an energizing electric source, causing the compressor #2 to shut down and the solenoid 42 to become deenergized, this latter causing the armature 36 to fall to open the previously described circuit including the contact 31 and resistor 38, and to close a circuit including the contact 43, the resistor 44, the resistor 38 and the fan motor 3 I. This connects the fan motor 3| in series with both resistors 44 and 38 causing another reduction in fan speed and volume.

When, as in the case of an outdoor temperature drop, the above described reductions in cooling surface and air volumes are insuflicient, the thermostat l8 opens the energizing circuit of the shutter control motor l3 causing it to close its associated shutters I2 in front of the coils 6 and to open the shutters 45 in a by-pass through the conditioner 5 around all of the coils. The resulting drop in the temperature of the refrigerant enter- 45 ing the compressor #1 through the thermo-responsive valve 46 causes it to open the energizing circuit of the compressor driving motor 41 to shut down the compressor #l.

The system then operates automatically as a 50 ventilating system until a change in the temperature of the outside or of-the recirculated air indicates that refrigeration is required, following which the thermostat will act to place the requisite cooling surface intoservice and to regulate the fan volume accordingly.

During the operation 'of the system as described in the foregoing, by-pass air enters through the duct 48, the mixing chamber 48 at the output side of the conditioner 5, and serves to raise the sensible heat of the air leaving the conditioner.

No damper adjustment of the by-pass air is necessary due to the fact that its volume varies in accordance with the total air volume and the effective coil surface, so that at all times the system is in balance.

The embodiment of the invention illustrated by Fig. 2 is essentially the same as that described above in connection with Fig. 1, except that a single source of refrigeration, which may be an indirect source, supplies refrigeration to all three groups of air cooling coils, and no thermostat such as control thermostat I8 01 Fig. 1 is used.

The coils themselves determine the amount of cooling surface and air volume required. If when all coils are in service, the refrigerant returned to the source shows by arriving at too low a temperature, that the maximum cooling effect is not required, first one and then the others of the groups of coils are rendered inactive. Most of the apparatus is similar to that shown by Fig. 1 so that the same reference characters will be applied to apparatus common to both figures.

The refrigeration supply 58 supplies a cooling liquid through the pipe to the coils 6, 1 and 8 which are in series with respect to fluid flow when all are in service. Between coils 6 and 1 is the two way valve 52 which may be adjusted by the solenoid 53 to close off the entrance of the liquid to the coils 1 and to return it through the pipe 54 to the supply 58. Between coils I and 8 is a similar valve 55 which may beadjusted by the solenoid 56 to close off the entrance of the fluid to the coils 8 and to return the fluid leaving coils l to the supply 58, through the pipe 51. Normally, when all of the coils are active, the refrigerant passes through all coils and returns to the source 58 through pipe 58.

In the common return pipe 59 to the source 58 are mounted the thermostats 68 and 6|. With all three groups of coils 6, 1 and 8 active, when the load on the coils is such that their total effect is not necessary, this is indicated by too low a tem perature of the refrigerant passing first through the thermostat 68, on its return to the source 58. This causes the thermostat 68 to open a circuit including the electric source, the solenoid 26, the shutter control motor I! and the solenoid 56, causing the solenoid 56 to adjust the valve 55 to by-pass the refrigerant around the coils 8; causing the motor I! to close its associated shutters I 6, and causing the solenoid 26 to connect the resistance 38 in the circuit of the fan motor 3|, as described in connection with Fig. 1, to decrease the fan speed'and volume.

If this reduction is not sufficient, the thermostat 6| responds to open a circuit including the electric source. the solenoid 42, the shutter control motor l5, and the solenoid 53. This causes the solenoid 53 to adjust the valve 52 to by-pass the refrigerant around the coils 1; causes the motor I5 to close the shutters l4 before the coils 1, and causes the solenoid '42 to close a circuit to connect resistors 44 and 38 in the circuit of the fan motor 3| as described above in connection with Fig. 1.

If this reduction is not sufficient, the thermostat 62 in the enclosure 28 opens a circuit including the motor 63 of the refrigeration supply, to discontinue the supply of refrigeration to the coils, and including the shutter control motor l3 causing it to close the shutters |2 in front of the coils 6. At.-the same time, the motor l3 opens the shutters 45 to enable ventilating air to bypass the coils in the conditioner 5. When the temperature within the enclosure 28 rises above the setting of the thermostat '62, it functions to supply refrigeration to the coils 6. If this is not sufficient, the thermostat 68 places the coils 8 in service.

The embodiment of the invention illustrated by Fig. 3 is similar to that described above in connection with Fig. 1 except that no shutters are placed in front of the coils 6; no by-pass in the conditioner around the coils is provided, and

a device which determines the number of persons in the enclosure 28, adjusts the volume of outside air in proportion to the number of persons in the enclosure. The remainder of the apparatus and its method of operation are similar to ping the compressor that-illustrated by Fig. 1 so that the same reference characters are used for this apparatus common to Figs. 1 and 3.

In the fresh outside air inlet duct 23 are mounted the dampers 64 adjustable by the solenoid 65 from one third open to wide open positions. The current supply to the solenoid 65 and to the shutter control motors l5 and I1 is controlled by the counting mechanism which will now be described.

As illustrated no occupants are in the enclosure 28 and the system is running at minimum capacity with only the coils 8 and compressor #I active; with the outside air'damper 64 two thirds closed, and the fan 39 operating at one third volume. During this period of minimum load, the thermostat 63 in the recirculated air duct 2i, controls the conditioner 5 by starting and stop- Persons entering the enclosure 20 pass in the entrance 86 in single file and in so doing interrupt the light beam from the light source 6'! to the photo-electric cell '68. The current impulses in the cell 68 are amplified by the amplifier 69 and are then fed into the counter 18 which may be similar to those disclosed by Patent Re. 18,567, issued August 9, 1932 to R. J. Wensley et al., and which as the impulses accumulate, rotate the gear II, in mesh with the gear 12, which is threaded internally to mesh with the threads on the shaft 13 so that the shaft 13 on which is mounted the resistor 14 moves from left to right (facing the drawing) as the number of people entering the enclosure 20 increases. During the movement of the shaft 13 and resistor M, the contact 15 moves across the face of the resistor M to decrease the resistance of and increase the current flow in, the energizing circuit of the armature coil 16 of the galvanometer indicated generally by 11.

During this time, any persons leaving the enclosure 20, pass in single file through the exit I8 and in so doing, interrupt the light beam between the source '59 and the photo-electric cell 88, causing current impulses 'to be amplified in the amplifier 8i and to flow into the counter 82, similar to the counter 10, but rotating in the opposite direction to tend through the action of the gears 83 and 84 to move the shaft 13 and resistor M to the left (facing the drawing), thus tending to increase the resistance in the energizing circuit of the galvanometer coil 16. When a person enters and another person leaves the enclosure at the same time, the counters 10 and 82 oppose each other and the resistor does not move. As more persons enter than leave the enclosure 20, the resistance in the energizing circuit of the galvanometer coil 16 is decreased to cause the coil 16 and its contact arm 85 to move to the right (facing the drawing) in proportion to the decrease in resistance, which in turn is proportional at any time, to the number of persons who have entered the enclosure 20 and have not left.

As the number of persons in the enclosure 20 increases, the coil 18 moves the arm 85 to the right (facing the drawing), and the contact 86 is moved across the resistance 81 to decrease the value of the resistance in the energizing circuit of the solenoid 65, causing it to move its damper 64 towards open position, proportional to the number of persons in the enclosure.

When the persons. in the enclosure 20 have increased to a predetermined number, the arm 85 moves against the contact segment 88 closing the energizing circuit of the shutter control motor the shutter control motor l5, causing it to become energized to adjust the shutters I4, before the coils I to open position. The thermostat 40 then causes the compressor #2 to start up.

When the persons in the enclosure have further increased to a larger predetermined number, the contact arm tact segment 89 to close the energizing circuit of H causing it to adjust its shutters l6, before the coils 8, to open position. The thermostat 24 then places the compressor #3 into operation.

The thermostat '83 in the recirculated air duct 2| acts to prevent too cold air from being supplied into the enclosure 20 by shutting down the compressor #I when the recirculated air indicates that too much cooling is being done in the conditioner. This has the double effect of decreasing the refrigeration effect, and of increasing the by-pass air effect due to the relatively high temperature untreated air passing through the now inactive coils 6 to mix with and raise the sensible heat of the air passing in contact with the active coils.

The speed and volume of the fan 39 is automatically increased by the action of the relays 26 and 42, when the coils I and 8 are placed in service, so as to vary the total volume of air passing through the conditioner in accordance with the load within the enclosure 20. The volume of fresh air is varied by the adjustment of the fan 39 when the total volume handled by the fan is adjusted, but the proportion of fresh air to recirculated air is adjusted by the damper 85 which also, of course, varies the total volume of fresh air entering the conditioner.

A volume of exhaust air equal at all times to that of the outside make-up air admitted into the conditioner, is vented from the enclosure through outlets which may be special exhaust outlets or which may be the ever present cracks and crevices.

While the means for the control of volume of the fan has been illustrated as a speed control means, it is obvious that the volume may be regulated by adjustment of spin inducing vanes in the fan inlet. For example, fans provided With control vanes such as are disclosed by the Patents No. 1,846,863, or No. 1,989,413 to H. F. Hagen may be had with automatic adjusting mechanism such as disclosed in application Ser. No. 81,455 filed May 23, 1936.

Whereas several embodiments of the invention have been described for the purpose of illustration. it should be understood that the invention is not to be limited to the exact arrangement described, as many departures may be made by those skilled in the art, after having had access to this disclosure.

What is claimed is:

1:. Air conditioning apparatus comprising a plurality of air coolers, means for supplying refrigerant to said coolers, a. fan for passing a stream of air through said coolers and into a room to be supplied with conditioned air, and means responsive to a function of the psychrometric condition of the air in said room for varying the volume of air moved by said fan and the number of said coolers exposed to said air stream.

2. Air conditioning apparatus comprising a plurality of air coolers, means for supplying refrigerant to said coolers, a fan for passing a stream of air through said coolers and into a room to be supplied with conditioned air, and

85 moves against the conmeans responsive to a function of the psychrometric condition of the air in said room for varying the volume of air moved by said fan, the number of said coolers supplied with refrigerant,

5 and the number of said coolers exposed to said air stream.

3. Air conditioning apparatus comprising an air cooling chamber, a plurality of groups of air cooling coils in said chamber, a fan for passing 10 a stream of air through said chamber and for discharging it into a roomto be supplied with conditioned air, means for selectively supplying said groups of coils with refrigerant, and means responsive to the temperature of one of said 15 groups of coils for varying the number of said groups of coils to be supplied with refrigerant.

4. Air conditioning apparatus comprising a plurality of air coolers, a fan for passing a stream of air through said coolers and for discharging 20 it into a room to be supplied with conditioned air, means for selectively supplying said coolers with refrigerant, and means responsive to the temperature of the refrigerant returned to said last mentioned means for varying the number of 25 said coolers to be supplied with refrigerant.

5. Air conditioning apparatus comprising an air cooling chamber, a plurality of groups of air cooling coils in said chamber, a fan for passing a stream of air through said chamber and for 30 discharging it into a room to be supplied with conditioned air, means for selectively supplying said groups of coils with refrigerant, and means responsive to the temperature of the refrigerant returned to said last mentioned means for varying the number of said groups of coils to be supplied with refrigerant.

6. Air conditioning apparatus comprising a plurality of coolers, a fan for passing a stream of air through said coolers and for discharging 40 it into a room to be supplied with conditioned air, means for selectively supplying said coolers with refrigerant, means responsive to the temperature of the refrigerant returned to said last mentioned means for varying the number of. said 45 coolers to be supplied with refrigerant, and for removing the ineffective coolers from said air stream.

7. Air conditioning apparatus comprising in combination a room to be supplied with condi- 50 tioned air, an air cooling chamber, air cooling means in said chamber, a fan for moving air through said chamber and for discharging it into said room, means for supplying refrigerant to said air cooling means, means for determining the approximate number of people in said room, and means including said last mentioned means for controlling the conditioning of the air by said apparatus.

8. Air conditioning apparatus comprising in 60 combination a room to be supplied with conditioned air, an air cooling chamber, air cooling means in said chamber, means for supplying outside air into said chamber for conditioning, a fan for moving air through said chamber and for 65 discharging it into said room, means for supplying refrigerant to said air cooling means, means for determining the approximate number of people in said room, and means including said last mentioned means for varying the volume 7 of outside air entering said chamber.

9. Air conditioning apparatus comprising in combination a room to be supplied with conditioned air, an air cooling chamber, air cooling means in said chamber, means for supplying 75 outside air into said chamber for conditioning,

a fan for moving air through said chamber and for discharging it into said room, means for supplying refrigerant to said air cooling means, means for determining the approximate number of people in said room, and means including said last mentioned means for varying the volume of outside air entering said chamber, and the supply of refrigerant to said air cooling means.

10. Air conditioning apparatus comprising in combination a room to be supplied with condi- 10 tioned air, an air cooling chamber, air cooling means in said chamber, means for supplying outside air into said chamber for conditioning, a fan for moving air through said chamber and for discharging it into said room, means for supplying refrigerant to said air cooling means, means for determining the approximate number of people in said room, and means including said last mentioned means for varying the volume of outside air entering said chamber, the supply of refrigerant to said air cooling means, and the total volume of air supplied by said fan into said room.

11. Air, conditioning apparatus comprising in combination a room to be supplied with conditioned air, a plurality of air coolers, means for supplying outside air to said coolers for conditioning, a fan for moving air through said coolers and for discharging it into said room, means for supplying refrigerant to said coolers, means for determining the approximate number of people in said room, and means including said last mentioned means for varying the volume of outside air entering said chamber, and the number of said coolers in contact with said air stream.

12. Air conditioning apparatus comprising in combination a room to be supplied with conditioned air, an air cooling chamber, a plurality of groups of air cooling coils in said chamber, means for supplying outside air into said chamber for conditioning, a fan for moving air through said chamber and for discharging it into said room, means for supplying refrigerant to said air cooling means, means for determining the approximate number of people in said room, and means including said last mentioned means for varying the volume of outside air entering said chamber, the number of said groups of coils in contact with the air stream through said chamber, and ,for controlling the supply of refrigerant to said coils.

13. Air conditioning apparatus comprising in combination, an enclosure to be supplied with conditioned air, a conditioning unit, means for supplying conditioned airfrom said unit into said enclosure, means for supplying fresh air into said unit, counting means for determining the approximate number of occupants of said enclosure, said last mentioned means including totalizing means for adding increases andfor subtracting decreases in the approximate number of occupants, and means utilizing said totalizing means for varying the volume of fresh air in accordance with the number of occupants of said enclosure.

14. Air conditioning apparatus comprising in combination, an enclosure to be supplied with conditioned air, a conditioning unit, means for supplying conditioned air from said unit into said enclosure, means for supplying fresh air into said unit, means for supplying air recirculated from said enclosure into said unit, counting means for determining the approximate number of occupants of said enclosure, said last mentioned means including totalizing means for adding increases and for subtracting decreases in the approximate number of occupants, and means utilizing said totalizing means for varying volumes of fresh and recirculated air substantially in accordance with changes in the number of occupants of said enclosure.

15. Air conditioning apparatus comprising in combination, an enclosure to be supplied with conditioned air, a conditioning unit, means for supplying air recirculated from said enclosure into said unit for conditioning, means for supplying fresh air into said unit, means for supplying air recirculated from said enclosure as bypass air, to the output side of said unit, counting means for determining the approximate number of occupants of said enclosure, said last mentioned means including totalizing means for adding increases and for subtracting decreases in the approximate number of occupants, and means utilizing said totalizing means for varying the volumes of fresh air, recirculated air, and bypass air as changes in the number of occupants of said enclosure take place.

ROBERT T. PALMER.

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