US2907178A

US2907178A - Air conditioning systems

Info

Publication number: US2907178A
Application number: US688168A
Authority: US
Inventors: Ralph D Mcnatt
Original assignee: Borg Warner Corp
Current assignee: Borg Warner Corp
Priority date: 1957-10-04
Filing date: 1957-10-04
Publication date: 1959-10-06
Anticipated expiration: 1976-10-06

Description

Oct. 6, 1959 R. D. MCNATT AIR CONDITIONING SYSTEMS 2 Sheets-Sheet 1 Filed Oct. 4, 1957 INVEA (Uh RALPH D. M: M477 wZON mO mw. .Z OP Nu mu 8 a ATTOR Oct. 6,1959 R. D. M NATT AIR CONDITIONING SYSTEMS 2 Sheets-Sheet 2 Filed 001;. 4, 1957 uZON INVENTQR. RALPH D. Mc/verr ATTQHA United States Patent AIR CONDITIONING SYSTEMS Ralph D. McNatt, Columbus, Ohio, assiguor toLBorg- Warner Corporation, Chicago, 111., a corporation of Illinois Application October 4, 1957, Serial No. 688,168 17 Claims. (Cl. 62-95) This invention relates to air conditioning systems for year-round conditioning of multi-room buildings.

The invention more particularly relates to that type of system disclosed in the applications of Robert D. Blum Serial No. 63 8,962, filed February 2, 1957, and Serial'No. 670,202, filed July 5, 1957, both owned by the assignee of my invention.

In said systems, conditioning of the air within a room is effected through the use of two mediums. Water is chilled in a refrigerating system and this chilled water is fed to a coil which is in heat-exchange relation with the room air, thereby effecting local conditioning of the room air. As used herein, the term water means any suitable heat-exchange liquid or brine which may be used effectively as a heat-exchange medium. This chilled water takes care of any internal sensible heat gains within the room imposed by people, lights, solar effect, etc. In addition, outside or primary air is conditioned in a central conditioner and is fed to the room to take care of sensible heat transmission through the walls and glass areas of the room. When the outside temperature is above the temperature it is desired to maintain in the room, this outside air is cooled to compensate for the sensible heat transmission gains into the room. When the outside temperature drops below the temperature it is desired to maintain in the room, the outside air is heated to compensate for the sensible heat transmission losses from the room.

In the above systems, as disclosed by Blum, heat picked up by the chilled water is dissipated into the incoming primary air at such times of the year as the primary air requires heating or reheating. Reference may be had to said Blum applications for a discussion of the advantages of said systems.

I now propose a system similar in its basic operation to the above Blum systems, but wherein the internal sensible heat picked up by the chilled water flowing within the room coils may be dissipated in the outside air being supplied to an interior zone of the building for ventilation purposes. By an interior zone I mean any zone within the building that requires cooling only, due to internal sensible heat gains, there being no heat transmission what soever. Such a zone would be found, for example, in the interior of a building wherein there are no outside walls through which to lose or gain heat. Such an interior zone is distinguished from an exterior zone wherein there are both heat transmission gains and heat transmission losses. In such an interior zone, a mixture of fresh ventilation air and recirculated air, generally called secondary air, is supplied to the rooms at a temperature of about 48 F. to provide the necessary cooling. The same cooling means used to chill the water supplied to the exterior zone room coils is generally used to cool the secondary air down to 48 F. at such times of the year as the outside temperature is above 48 F.

I now propose that heat picked up by the chilled water in the exterior zone room coils be dissipated in the incoming ventilation air for the interior zone of a building during such times of the year as heat is needed to raise the temperature of this incoming air to the desired 48 F. If insufficient heat is available from the chilled water to maintain the desired 48 F. temperature, then recirculated air is added to provide for the deficiency. This is distinguished from conventional systems wherein at such times of the year when the outside temperature is lower than 48 F., recirculated air from the interior zone is mixed with the incoming ventilation air as the sole means for maintaining the 48 F. temperature. Dissipating heat picked up by the chilled water into incoming ventilation air for the interior zone has two effects: one, it enables more fresh air to be brought into the interior of a building, With consequently less use of recirculated air and therefore provides better ventilation, and two, it provides a supply of chilled water for the room coils of the exterior zone in the primary air system without the use of mechanical refrigeration.

During such times of the year as the outside temperature is below 48 F., I reverse the operation of the refrigerating system (which is no longer needed to supply chilled water to the room coils of the exterior zone) and utilize it as a heat pump to provide the heat necessary to heat up the incoming primary air for the exterior zone of the building to provide for the heat transmission losses therefrom.

It is among the objects of this invention to provide, in an air conditioning system for multi-room buildings having interior and exterior zones and of the type wherein conditioned air is delivered to exterior zone rooms to compensate for the heat transmission load thereof while a chilled heat-exchange fluid is supplied to the exterior zone rooms to counteract internal heat gains, means for dissipating heat picked up by said heat-exchange fluid into outside air supplied to interior zone rooms during those times of the year that the outside air needs heating.

Another object of the invention is to provide, in an air conditioning system for multi-room buildings having interior and exterior zones and of the type wherein conditioning units are located in air communication with respective rooms of the exterior zone with air being conditioned to compensate for the heat transmission load of the exterior zone rooms and then delivered to the units in such a manner as to induce a flow of room air through the units while a chilled heat-exchange fluid is fed to the units in heat-exchange relation with the room air flowing there through to counteract internal heat gains and fresh air is supplied to the interior zone rooms at a temperature to compensate for the internal heat gains therein, means for rejecting the heat picked up by the heat-exchange fluid into the interior zone fresh air at such times of the year as the temperature of said fresh air is lower than needed to compensate for said internal heat gains.

Yet another object of the invention is to provide, in an air conditioning system for multi-room buildings and of the type wherein air is conditioned and delivered to said rooms to compensate for the heat transmission load of said rooms while a heat-exchange fluid is chilled and supplied to said rooms to counteract internal heat gains therein and a refrigerating system is provided for chilling said heat-exchange fluid and for cooling said air during such times of the year that there is a heat transmission gain into said rooms, means for reversing said refrigerat ing system for operation as' a heat pump to heat said airv side air to compensate for internal heat gains therein,

Patented Oct. 6, 1959 the type above noted and wherein? p the building includes an interior zone supplied with out= means for utilizing the outside air for chilling the heatexchange fluid during heat pump operation of the refrigerating system.

The invention consists of the novel constructions, arrangements and devices to be hereinafter described and claimed for carrying out the above-stated objects and such other objects as will appear from the following description of preferred embodiments of the invention described with reference to the accompanying drawings, in which:

Fig. 1 is a diagrammatic representation of an air conditioning system according to the invention operating on a summer and intermediate cycle of operation; and

Fig. 2 is a diagrammatic representation of the system of Fig. 1 operating on a winter cycle of operation.

Like numerals refer to like parts throughout the two views.

In conditioning a building according to the invention, the building is divided generally into four exterior zones' north, east, south and west to take due account of the solar effect on any exposure-and an interior zone. Since the primary air is conditioned to take care of the sensible heat transmission loss or gain from the exterior zones, the various rooms within the building making up a zone must be selected on some basis allowing for approximately the same primary air temperature.

Turning now to Fig. 1, each exterior zone is provided with a zone conditioner comprising a casing 11 in which is located a filter 12, a dehumidifying coil 13, a reheat coil 14, and a fan 15 of any convenient type. Air inlet dampers 16 are provided in the casing 11 for admitting the primary air thereto. A recirculated air inlet 17, including dampers 18, is also provided for admitting recirculated air into casing 11.

Suitable chilled water coils are provided in heatexchange relation with the air in the various exterior zone rooms R (only one of which has been shown) to be conditioned. In order to provide for the necessary air movement over the various chilled water coils, 1 provide a so-called induction unit 19 in or near each room to be conditioned. Only one such unit has been shown, but it will be appreciated that as many units will be provided as is necessary to serve the zone, with one or more units being in air communication with each room to be conditioned. Each unit comprises a chilled water coil 20, a plenum chamber 21, an air discharge nozzle 22, and an air outlet 23 from which the air is discharged into the room to be conditioned. A discharge duct 24 serves to connect fan 15 to branch conduits 25, which terminate in discharge openings 26 in the various units 16.

A conditioner 27 is provided for conditioning the air supply to the interior zone. Conditioner 27 comprises a casing 28 having a fresh-air inlet 29 and a recirculated air inlet 30, and includes a heat-exchange coil 31. A fan 32 is provided for inducing a flow of fresh and recirculated air through casing 28 and an adjustable damper 33 is so located within the casing as to properly proportion the amounts of fresh air and recirculated air flowing through the casing. Damper 33 is so proportioned that it cannot completely out ofi the flow of fresh air and, therefore, always provides sufficient air for ventilation. Fan 32 discharges into a discharge duct 34 which leads to outlet grills (not shown) in the various rooms of the interior zone. The positioning of damper 33 is effected by a damper motor 35 which is controlled by a thermostat 36, located in air stream off of coil 31. Recirculated air out let 37, including dampers 38, is provided for discharging recirculated air from the building when such is necessary.

Central refrigerating means are provided for supplying chilled water to the various primary air coils 13, to the exterior zone room coils and to the interior zone coil 31 at any desired temperature.. Any type of refrigerating system with the usual thermostatic controls for maintaining a desired chilled water temperature is provided and includes liquid heat-exchanger 39 operative both as a water chiller and as a water-cooled condenser. The refrigerating system also includes a water-cooled condenser 40, an air heat-exchanger 41 operative both as an air cooler and as an air-cooled condenser, and a compressor 42 of any suitable type. A reversing valve 43, having

junctions

43a, 43b, 43c and 43d, is provided. The discharge of compressor 42 is connected to junction 43a by way of a hot gas line 44. Junction 430 is connected to the suction of compressor 32 by Way of a cold gas line 45. Liquid heat-exchanger 39 is connected to junction 43d by Way of a refrigerant line 46 and air heat-exchanger 41 is connected to junction 43b by way of a refrigerant line 47. The liquid heat-exchanger 39 and the air heatexchanger 41 are connected by a liquid refrigerant line 48 including thermostatic expansion valves 49 and 50 of the customary type.

The thermostatic valve includes a thermometric bulb which contains a volatile fluid, so chosen that it will develop a suitable pressure at the desired temperature of the vaporous refrigerant leaving the evaporator. The pressure thus developed in the bulb is transmitted through a capillary tube to the expansion valve and there acts upon a pressure motor mechanism, which is, as usual, connected to actuate the valve element of the expansion valve.

A bypass 51 containing a check valve 52 is provided about expansion valve 49. A similar bypass 53 containing a check valve 54 is provided about expansion valve 50. Water cooled condenser 40 is interconnected between refrigerant lines 47 and 48 by way of a refrigerant line 55, including check valves 56 and 57.

Water cooled condenser 40 may be of any suitable type and utilizes water from any source as a cooling medium. A liquid pump 58 is provided for circulating the cooling water through the condenser and is connected to the condenser by line 59. Pump 58 discharges into a line 60 which leads into reheat coil 14 in conditioner 10. Line 60 is connected to reheat coil 14 by way of a modulating valve 61. From reheat coil 14 a line 62 leads back to the water cooled condenser 49 to complete the circuit.

The air heat-exchanger 41 may also be of any suitable type and includes a refrigerant coil 63 and a fan 64 for circulating outside air thereover.

Throttling of air flow over coil 63 in order to vary the heat-dissipating effectiveness of condenser 41 is effected by a plurality of dampers 65 controlled by a damper motor 66. A thermostatic bulb 67 is attached to line 55 and is connected to damper motor 66 by way of a capillary 68.

Liquid heat-exchanger 39 will be generally similar to water cooled condenser 40 and provides for flow of water therethrough in heat-exchange relation with the refrigerant therein. A liquid pump 69 serves to circulate the Water through the heat-exchanger 39 and is connected thereto by way of a line 70. Pump 69 discharges into a header 71 which terminates in a liquid line 72. Line 72 leads to three-way valve 73 having junctions 73a, 73b and 73c, with line 72 being connected to junction 73a. The second junction 73b of valve 73 is connected with heatexchange coil 31 by a line 74. The third junction 730 of valve 73 is connected by way of a line 75 to a second three-way valve 76 through a junction 76a therein. A second junction 76b of valve 76 is connected to a header '77 into which lines 78 leading from room coils 20 discharge. A third junction 760 of valve 75 is connected by a line 7 9 to a header 8% leading back to the liquid heatexchanger 39.

A discharge line 81 is connected to the outlet of heatexchange coil 31 and terminates in a liquid pump 82. Pump 82 discharges into a header 83. From header 83, lines 84 lead to the inlet of corresponding heat-exchange coils 2%. Flow through lines 34 is regulated by a threeway valve 85. Valve 85 is controlled by thermostat 86 located in the conditioned space. A bypass line 87 is provided around the chilled liquid coil 20 via the threeway valve 85 terminating in line 78. Flow. through valve 85 is normally from line 84 into line 87. As the temperature within the conditioned space rises, thermostat 86 actuates valve 85 such that a partial flow is allowed from line 84 into line 85 with the remainder of the flow going through line 87.

A bypass line 88 is provided around coil 31 and includes a normally closed modulating valve 89 controlled by thermostat 36. Line 88 joins line 74 and line 81. A line 90 joins line 75 and line 81 via a modulating Valve 91 controlled by a thermostatic bulb 92. Modulating valve 91 normally allows no flow from line 90 into line 81 and oflers no impedance to flow through line 81.

A line 93 leads from header 71 to each of the various zone conditioners 10. Line 93 is connected to a threeway valve 94 by way of a junction 94a. A second junction 94b of three-way valve 94 is connected to the inlet of dehumidifying coil 13 by a line 95 including a modulating valve 96. A third junction 940 of three-way valve 94 is connected to a line 97 for bypassing valve 96. Bypass line 98 leads from three-Way valve 96 to a line 99 connecting the discharge end of coil 13 with header 80. Modulating valve 96 normally allows no flow from line 95 into line 98 and otters no impedance to flow through line 95.

A master-submaster thermostatic arrangement is provided for controlling water flow through coils 13 and 14 and includes a thermostat 100 located in the leaving air stream ofl conditioner and a thermostat 101 located in the entering air stream. A thermostat 102 controls the operation of dampers 18.

Operation Turning now to the drawings the various operational cycles will be described. Directing attention now to the refrigerating system, when it is desired to supply chilled water to dehumidifying coil 13, room coils 20 and heatexchange coil 31, valve 43 is set as shown in Fig. 1. Hot compressed gas leaves compressor 42 by way of line 44 and is directed by valve 43 into line 47 whence it flows through the water cooled condenser 40. The hot gas within the condenser 40 gives up its heat to water flowing therethrough under the influence of pump 58 becoming condensed thereby. Dampers 65 under control of damper motor 66 will normally be in a closed position.

It will be apparent that during such times of the year that all the heat dissipated in water cooled condenser 48 cannot be utilized in reheat coil 14, then the temperature of the water in condenser 40 begins to rise. Thermostatic bulb 67 then senses this temperature rise and functions to open dampers 65 allowing flow of air through the air heat-exchanger 41 now functioning as an air cooled condenser, which then begins to carry a part of the load. It will be seen, therefore, that a substantially constant water leaving temperature is maintained in Water cooled condenser 40. The heat of the hot gas flowing through coil 63 of air heat-exchanger 41 when dampers 65 are open is dissipated to the outside air flowing thereover under the influence of fan 64, the refrigerant becoming condensed thereby. The refrigerant liquid exits the air heatexchanger 41 by way of bypass line 53 and thence flows into line 48. The refrigerant liquid exits condenser 40 by way of line 55 and thence merges with the refrigerant liquid leaving the air cooled condenser 41. The refrigerant liquid then flows through thermostatic expansion valve 49 whereby the pressure and corresponding temperature is reduced. An increase in temperature of the refrigerant flowing through line 46, indicating a too low refrigerant flow rate, is reflected by an increase in the pressure of the volatile fluid to actuate the valve element to allow for greater flow of refrigerant therethrough. The cooled refrigerant liquid flowing through heat-exchanger 39 picks up heat from the water flowing therethrough under the influence of pump 69 becoming vaporspotted ized thereby. The now gaseous refrigerant leaves the liquid heat-exchanger 39 by way of line46 and is then directed by valve 43 into line 45 whence it flows to the suction side of compressor 42 to complete the cycle.

of bypass line 52 into line 48 and thence through themestatic expansion valve 50', which operates similarly to valve 49, whereby its pressure and corresponding temperature is reduced. '(It will be noted that the Water cooled condenser 40 is inoperative during the heat pump cycle of operationwith check valve 57 operating to restrict refrigerant flow therethrough.) The cooled liquid flows through heat-exchange coil 63 of air heat-exchanger 41 now functioning as an air source evaporator. In flowing through coil 63 the liquid picks'up heat from the air flowing thereover under the influence of fan 64 becoming vaporized thereby. On the heat pump cycle dampers 65 are flxedlypositioned fully opened, by lock means (not shown). The gaseous refrigerant exits coil 63 by way of line 47 and is directed by four-way valve 43 into line 45 whence it flows to the suction side of compressor 42, thereby completing the cylcle.

The air conditioning system 'disclosedoperates on three cycles: one, the summer cycle wherein the outside temperature is above the temperature it is desired to maintain within the conditioned spaces of the exterior zone; two, the winter cycle wherein the outside temperature is sufliciently below the temperature at which it is desired to supply the secondary air to the interior zone (approximately 48 F.) for 100% outside air (no recirculated air) to chill the water supplied heat-exchange coils 20 down to the desired temperature (approximately 52 F.) under maximum heat load while the outside air is being heated to its desired 48 F. temperature; and three, the intermediate cycle wherein the outside temperature is below the temperature it is desired to maintain within the conditioned spaces of the exterior zone and above the temperature at which the system goes on the winter cycle.

Turning now to Fig. 1, the cold and hot water flow for the summer and intermediate cycles will be traced: valve 73 is set to provide communication between

lines

72 and 74. Valve 76 is set to provide communication between header 77 and line 79. Valve 94 is set to communicate line 93 with bypass 97. The refrigerating system is operating on its normal refn'gerating cycle and valve 43 is set as shown in Fig. 1.

During summer and intermediate cycle operation of the system, chilled water is supplied to dehumidifying coil 13, and heated condenser water from condenser 40 is avail able for reheat purposes in coil 14.

Chilled water leaves heat-exchanger 39 under the influence of pump 69 and flows into header 71. Part of the chilled water flows through

lines

93 and 97 into the dehumidifying coil 13, serving to cool and dehumidify the fresh air flowing thereover under influence of fan 15. The chilled water exits coil 13 by way of line 99 and flows back into header and thence into the heatexchanger 39 to complete the circuit for this portion of the water flow.

The balance of the chilled Water flows from header 71 into line 72 and is then directed by valve 73 into line 74 whence it flows through coil 31, serving to cool and dehumidify the ventilation air flowing thereover, which air is then supplied by fan 32 to the interior zone. Thermostat 36 actsto maintain a constant air leaving temperature of approximately 48 F. off of coil 31. Should the air off of coil 31 be less than 48 F., then valve 89 is partially opened to bypass part of the chilled water flow around coil 31. Conversely, should the air temperature off of coil 31 be greater than 48 F., then valve 89 is closed under the influence of thermostat 36 to route the full supply of chilled water through coil 31. Means (not shown) are provided for maintaining damper 33 in its dotted line position, admitting only suflicient fresh air for ventilation purposes.

The chilled water exits coil 31 by way of line 81 under the influence of pump 32 and then flows into header 83 and thence into the various lines 84 leading to the coils 20 of room units 19. Should any or all of the valves 85 be positioned to allow no flow through the respective coils 20, then the chilled water is bypassed therearound by way of bypass line 87. This insures full flow of chilled water through coil 31 at all times to properly condition the ventilation air.

Assuming, however, that some cooling is needed within the exterior spaces to be conditioned, then the various valves 85 allow flow into coils 21} under the influence of room thermostats 86. It will be appreciated that valves 85 are modulating valves, that is, they allow suflicient chilled water flow through coils 20 to satisfy the requirements of thermostats 86, at the same time acting to bypass part of the, water around the coils 26 should full flow of chilled water through the coils be unnecessary to maintain the desired temperature. The chilled water leaves the room coils 20 through line 78, flows into header 77 and is then directed into line 79 by valve 76. From line 79 the chilled water flows into header 80 returning to heatexchanger 39 to complete the cycle.

In the meantime, so long as no reheat is needed in coil 14, dampers 65 will be in their fully open position under the influence of thermostatic bulb 67 allowing all of the heat picked up by the refrigerating system from the water flowing through heat-exchanger 39 to be dissipated in the air cooled heat-exchanger 41.

During the summer cycle, primary air entering the conditioner 10 is filtered and cooled and dehumiditied by the chilled water flowing through coil 13 and delivered by fan 15 to the various room units 19. Fan 15 is generally of a constant speed type and of sufiicient capacity to deliver to all units 19 primary air at a suflicient static pressure to provide suthcient air velocity at the nozzles 22 to produce a desired induction effect when the primary air discharges within the units. As the high velocity primary air discharges from the nozzles 22., there is a sufficient pressure drop within the unit to induce a flow of room air therein, with the chilled liquid coil being placed in the path of room air flow to eifect local conditioning thereof. The mixture of primary air and room air then discharges through air outlet 23. The temperature of the air flowing through conditioner 10 is controlled to compensate for any sensible heat transmission gains by master-submaster thermostatic arrangement 1tl0101. Thermostat 100 is placed in the leaving air stream and controls valves 61 and 96. During both the summer and intermediate cycles of operation, thermostat 100 has no efiect on the chilled water flow through coil 13 since the chilled water is bypassed around valve 96. Thermostat 1% opens valve 61 to allow heated condenser water to pass through coil 14 for reheat purposes whenever reheating of the primary air is called for. Thermostat 101 is located outside the conditioned space and serves to reset thermostat we to provide hotter or colder air, as the outside temperature drops or rises respectively. The entire device is so calibrated that the temperature of the air entering the room units is such that the primary air provides for sensible heat transmission gains or losses. Since such an arrangement is well known and forms no part of the. invention per se, it is believed that the above description is adequate.

As soon as additional internal sensible heat gains in the form of people, light, solar effect, etc., are introduced into any space, then the appropriate thermostat 86 opens the corresponding valve 85 to provide the additional the water cooled condenser 40 carry part of the heat dis sipating load, which heat is then available for reheat purposes.

The intermediate cycle differs from the summer cycle only in that primary air is dehumidified and supplied to the units 19 at a temperature elevated sufliciently above the design temperature by reheat coil 14 to provide for sensible heat transmission losses. As before, coil 20 takes care of any internal sensible heat gains.

In the winter cycle, turning now to Fig. 2, valve 73 is set to provide communication between

lines

74 and 75. Valve 76 is set to provide communication between line 75 and header 77. Valve 94 is set to communicate line 93 with line 95. The refrigerating system operates as a heat pump and valve 43 is set as shown in Fig. 2.

Heat-exchanger 39 now functions as a refrigerant condenser and heat-exchanger 41 functions as a refrigerant evaporator. Heated condenser water leaving heatexchanger 39 flows under the influence of pump 69 into header 71 and thence into line 93, there being no flow permitted through line '72 by valve 73. From line 93 the heated water is directed by valve 94 into line 95. Valve 96 now functions to allow the necessary heated water flow through coil 13 to maintain the desired air temperature, as called for by thermostat 100. Should full flow of heated condenser water through coil 13 be unnecessary to maintain this desired temperature, part of the water is bypassed about coil 13 flowing through line 98 into line 99 and thence into header for return to the heat-exchanger 39. Thermostat 180 has no eifect on valve 61 since condenser 40 is inoperative during the winter cycle of the system.

Assuming that there is flow of heated condenser water through coil 13, then this water leaves the coil by way of line 99 flowing then into header 80 and thence through the heat-exchanger 39 picking up more heat from the compressed heated refrigerant gas flowing therethrough.

During the winter cycle, primary air entering the conditioner 10 is filtered and then heated by the hot water flowing through coil 13 and delivered by fan 16 to the various room units 19. The temperature of the air is controlled by thermostat 100 to compensate for sensible heat transmission losses from the various rooms.

As soon as internal sensible heat gains in the form of people, lights, solar eflect, etc. are introduced into any space, then the appropriate thermostat 86 opens the corresponding valve to provide the cooling needed.

At such times of the year that the primary air entering conditioner 10 may be sufliciently cold to present a freeze-up hazard in coil 13, then dampers 18 under the control of thermostat 102 partially open to admit recirculated air into conditioner 10 to maintain the temperature of the mixture flowing over coil 13 sufliciently high to insure no freeze-up. Thermostat 102 is set to maintain this temperature.

It will be readily seen that during the winter cycle there are in efifect two separate water flow systems, the first providing for heated water flow and consisting of coil 13 and heat-exchanger 39 and the various flow lines therebetween, and the second providing chilled water flow and consisting of coil 31 and the various heat-exchange coils 20.

The chilled water flow will now be traced. Water is circulated through coil 31 under the influence of pump 82. As was pointed out above, the system is changed over at such a temperature that with fresh air flowing over coil 31, the air in being heated from its entering temperature to its desired 48 F. temperature chills water flowing through coil 31 down to a temperature no greater than 52 F. under the maximum heat load. Three-way valve 85 acts to bypass Water around room coil 20 if the chilled water is too cold. Further, valve 91, under the influence of thermostatic bulb 92, functions to allow part of the water flowing from room coil 20 through line 75 to bypass coil 31, flowing instead through bypass line 90 to maintain approximately the desired temperature of the chilled water flowing through header 83.

Valve 89 is maintained in a closed position, by stop means, not shown, and thermostat 36 again functions to maintain the desired 48 F. air temperature off of coil 31. As the outside air temperature drops, there will be insufiicient heat in the water flowing through coil 31 to provide for the desired 48 F. temperature, since, as pointed out above, the system is changed over at such a temperature that the secondary air will be heated up to 48 F. under maximum conditions, i.e. under conditions of maximum heat being available. As the outside temperature drops then damper motor 35, under the influence of thermostat 36, serves to gradually bias damper 33 to allow for a partial flow of recirculated air through inlet 30 to maintain the desired temperature. Valve 91 then, of course, functions to maintain the desired chilled water temperature. Damper 33, as was pointed out above, is so proportioned that air flow through fresh air inlet 29 cannot be completely cut oif, therefore, ventilation requirements will always be supplied through fresh air inlet 29. This air is then delivered by fan 32 into conduit 34 and then circulated to the various rooms within the interior zone to be conditioned.

It will be apparent that, on the winter cycle and when the outside temperature is such that maximum amounts of fresh air will be brought into the interior zone of the building, some means must be provided for exhausting air from the building. This is taken care of by recirculated air outlet 37. Dampers 38 are of the spring. biased type and when the pressure Within outlet 37 builds up sufliciently to force dampers 38 open, the excess air exits the building.

The water flowing through coil 31 has its heat removed by the incoming fresh air and thence flows into line 81 and header 83 and the various lines 84 under the influence of pump 82. From the lines 84 it flows to the inlet of the various three-way valves 85. Should no cooling be called for by thermostat 86, then three-way valve 85 functions to divert the chilled water around coil 20. Upon a rise in temperature in the conditioned space, however, thermostat 86 resets valve 85 to allow sufllcient flow-of chilled water through coil 20. Chilled water then flows through line 78 and into header 77 and is directed by valve 76 into line 75 and thence through valve 73 into line 74 for further flow through heat-exchange coil 31. Should the temperature of the water leaving pump 82 be lower than desired, then valve 91 functions to bypass part of this Water into line 90 and thence into line 81 to raise its temperature.

It will be appreciated that one zone is completely independent of any other with the only common apparatus being the central refrigerating system which supplies heated and chilled water for all zones and, in winter, conditioner 27 which supplies chilled water for the room coils 20 of all zones. Also, all zones are considered in determining the changeover point. However, the number of zones varies from building to building with each zones operation being unaffected by another zones operation.

I wish it to be understood that my invention is not to be limited to the specific constructions and arrangements shown and described, except only insofar as the claims may be so limited, as it will be apparent to those skilled in the art that changes may be made without departing from the principles of the invention.

' What is claimed is:

1. A method of air conditioning a multi-room building having an interior and exterior zone comprising the steps of: conditioning primary air to compensate for the heat transmission load of said exterior zone rooms; delivering said primary air to said exterior zone rooms; supplying a heat-exchange fluid to said exterior zone rooms for heatexchange with room air to counteract internal heat gains; conditioning outside air to compensate for internal heat gains within said interior zone rooms; delivering said outside air to said interior zone rooms; dissipating heat picked up from said outside air and by said heat-exchange fluid outside of said building when said interior zone outside air requires cooling; and rejecting heat picked up by said heat-exchange fluid into said outside air when said outside air requires heating.

2. A method of air conditioning a multi-room building having an interior and exterior zone comprising the steps of: conditioning primary air to compensate for the heat transmission load of said exterior zone rooms; delivering said primary air to said exterior zone rooms; supplying a heat-exchange fluid to said exterior zone rooms for heat-exchange with room air to counteract internal heat gains; conditioning outside air to compensate for internal heat gains Within said interior zone rooms; delivering said outside air to said interior zone rooms; dissipating heat picked up from said outside air and by said heat-exchange fluid outside of said building when said interior zone outside air requires cooling; rejecting variable amounts of the heat picked up by said heat-exchange fluid into said outside air when said outside air requires heating and thereby maintaining the temperature of said heat-exchange fluid at a desired level; and controlling the temperature of said outside air to compensate for said internal heat gains Within said interior zone rooms by adding variable portions of recirculated air thereto.

3. An air conditioning system for multi-room buildings having an interior and exterior zone comprising, a plurality of heat-exchange coils in air communication with respective rooms of said exterior zone; means for supplying primary air to said exterior zone rooms; means for conditioning said primary air; means for supplying a heatexchange fluid to said exterior zone heat-exchange coils; means for flowing room air over said heat-exchange coils in heat-exchange relation therewith; means for supplying outside air to said interior zone rooms; and means for passing at least a portion of said heat-exchange fluid in heat-exchange relation with said outside air.

4. An air conditioning system for multi-room buildings having an interior and exterior zone comprising, condi tioning units located in air communication with respective rooms of said exterior zone, said units each including a heat-exchange coil and nozzle means; means for supplying primary air to said nozzle means for discharge through said units into said rooms at a sufiicient velocity to induce a flow of room air through said units and over said heat-exchange coils; means for conditioning said primary air; means for supplying a heat-exchange fluid to said heat-exchange coils; means for supplying outside air to said interior zone rooms; and means for passing at least a portion of said heat-exchange fluid in heatexchange relation with said outside air.

5. An air conditioning system for multi-room buildings having an interior and exterior zone comprising, a plurality of heat-exchange coils in air communication with respective rooms of said exterior zone; means for supplying primary air to said exterior zone rooms; means for conditioning said primary air; means for supplying a heat-exchange fluid to said exterior zone heat-exchange coils; means for flowing room air over said heat-exchange coils in heat-exchange relation therewith; means for supplying outside air to said interior zone rooms; a heatexchange coil in heat-exchange relation with said outside air; a chilled water source; and means for passing said chilled water through said outside air heat-exchange coil or for alternately passing at least a portion of said heat-exchange fluid through said outside air heat-exchange coil.

6. A method or" air conditioning a multi-room building having an interior and exterior zone comprising the steps of: heating primary air to compensate for heat transmission losses from said exterior zone rooms; delivering said primary air to said exterior zone rooms; supplying a heat-exchange fluid to said exterior zone rooms for heatexchange. with room air to counteract internal heat gains; delivering outside air to said interior zone rooms; and dissipating heat picked up by said heat-exchange fluid into said interior zone outside air.

7. A method of air conditioning a multi-room building having an interior and exterior zone comprising the steps of: conditioning primary air to compensate for the heat transmission load of said exterior zone rooms; delivering said primary air to said exterior zone rooms; supplying a heat-exchange fluid to said exterior zone rooms for heat-exchange with room air to counteract internal heat gains; delivering outside air to said interior zone rooms; and dissipating heat picked up by said heat-exchange fluid into said interior zone outside air when the temperature of said outside air is beneath its desired delivery temperature.

8. An air conditioning system for multi-room buildings comprising a plurality of heat-exchange coils in air communication with respective rooms; means for delivering primary air to said rooms; means for flowing room air over said coils in heat-exchange relation therewith; a conditioner for treating said primary air and including a heat-exchange coil; 21 refrigerating system for supplying chilled water to said room heat-exchange coils and to said primary air conditioner heat-exchange coil; means for reversing the operation of said refrigerating system for supplying heated Water to said primary air conditioner heat-exchange coil; and means independent of said refrigerating system for supplying chilled water to said room heat-exchange coils during said reversed operation.

9. An air conditioning system for multi-room buildings comprising a plurality of heat-exchange coils in air communication with respective rooms; means for supplying primary air to said rooms; means for flowing room air over said coils in heat-exchange relation therewith; a conditioner for treating said primary air and including first and second heat-exchange coils; a refrigerating system for supplying chilled Water to said room heatexchange coils and to said first primary air conditioner heat-exchange coil, said refrigerating system including a liquid cooled condenser; means for supplying heated condenser liquid to said second primary air conditioner heat exchange coil; means for reversing the operation of said refrigerating system for supplying heated Water to said first primary air conditioner heat-exchange coil; and means independent of said refrigerating system for supplying chilled Water to said room heat-exchange coils during said reversed operation.

10. An' air conditioning system for multi-room buildings comprising, conditioning units located in air communication with respective rooms, said units each including a heat-exchange coil and nozzle means; means for applying primary air to said nozzle means for discharge through said units into said rooms at a sufficient velocity to induce a flow of room air through said units and over said heat-exchange coils; a conditioner for treating said primary air and including first and second heat-exchange coils; a refrigerating system for supplying chilled water to said room heat-exchange coils and to said first primary air conditioner heat-exchange coil, said refrigerating system including a liquid cooled condenser; means for supplying heated condenser liquid to said second primary air conditioner heat-exchange coil; means for reversing the operation of said refrigerating system for supplying heated Water to said first primary air conditioner heatexchange coil; and means independent of said refrigerating zone rooms; and dissipating heat picked up by said heat-.

exchange fluid into said interior zone outside air when the temperature of said outside air is suificiently beneath its desired delivery temperature to absorb said heat without rising in temperature above said desired delivery temperature.

12. A method of air conditioning a multi-room building having an interior and exterior zone comprising the steps of: conditioning primary air to compensate for the heat transmission load of said exterior zone rooms; delivering said primary air to said exterior zone rooms; supplying a heat-exchange fluid to said exterior zone rooms for heat-exchange with room air to counteract internal heat gains; delivering outside air to said interior zone rooms; dissipating variable amounts of the heat picked up by said heat-exchange fluid into said interior zone outside air when the temperature of said outside air is sufficiently beneath its desired delivery temperature to absorb said heat without rising in temperature above said desired delivery temperature and thereby maintaining the temperature of said heat-exchange fluid at a desired level; and controlling the temperature of said outside air at said desired delivery temperature by adding variable portions of recirculated air thereto.

13.. An air conditioning system for multi-room buildings having an interior and exterior zone comprising, a plurality of heat-exchange coils in air communication witlrrespective rooms of said exterior zone; means for supplying primary air to said exterior zone rooms; means for conditioning said primary air; means for supplying a heat-exchange fluid to said exterior zone heat-exchange coils; means for flowing room air over said heatexchange coils in heat-exchange relation therewith; means for supplying outside air to said interior zone rooms; a heat-exchange coil in heat-exchange relation with said outside air; means for passing said heat-exchange fluid through said outside air heat-exchange coil; means for bypassing heat-exchange fluid around said outside air heat-exchange coil; and means for adding recirculated air from said interior zone to said outside air.

14. An air conditioning system for multi-room buildings having an interior and exterior zone comprising conditioning units located in air communication with respective rooms of said exterior zone, said units each including a heat-exchange coil and nozzle means; means for supplying primary air to said nozzle means for discharge through said units into said rooms at a suflicient velocity to induce a flow of room air through said units and over said heat-exchange coils; means for conditioning said primary air; means for supplying a heat-exchange fluid to said exterior zone heat-exchange coils; means for supplying outside air to said interior zone rooms; a heatexchange coil in heat-exchange relation with said outside air; means for passing said heat-exchange fluid through said outside air heat-exchange coil; means for bypassing heat-exchange fluid around said outside air heat-exchange coil for maintaining a desired temperature in said fluid; and means for adding recirculated air from said interior zone to said outside air for maintaining a desired temperature in said outside air.

15. An air conditioning system for multi-room buildings having an interior and exterior zone comprising a plurality of heat-exchange coils in air communication with respective rooms of said exterior zone; means for supplying primary air to said exterior zone rooms; means for may flowing room air over said coils in heat-exchange relation therewith; a conditioner for treating said primary air and including a heat-exchange coil; means for supplying outside air to said interior zone rooms; a conditioner for treating said outside air and including a heat-exchange coil; a refrigerating system for supplying chilled water to said room heat-exchange coils, to said primary air conditioner heat-exchange coil and to said outside air conditioner heat-exchange coil; means for reversing the operation of said refrigerating system for supplying heated water to said primary air conditioner heatexchange coil; and means for directing Water from said room heat-exchange coils in a circuit through said outside air conditioner heat-exchange coil and thence back to said room heat-exchange coils during said reversed operation.

16. An air conditioning system for multi-room buildings having an interior and exterior zone comprising a plurality of heat-exchange coils in air communication with respective rooms of said exterior zone; means for supplying primary air to said exterior zone rooms; means for flowing room air over said coils in heat-exchange relation therewith; a conditioner for treating said primary air and including first and second heat-exchange coils; means for supplying outside air to said interior zone rooms; a conditioner for treating said outside air and including a heat-exchange coil; a refrigerating system for supplying chilled Water to said room heat exchange coils, to said first primary air conditioner heat-exchange coil and to said outside air conditioner heat-exchange coil, said refrigerating system including a liquid cooled condenser; means for supplying heated condenser liquid to said second primary air conditioner heat-exchange coil; means for reversing the operation of said refrigerating system for supplying heated water to said first primary air conditioner heat-exchange coil; and means for directing water from said room heat-exchange coils in a circuit through said outside air conditioner heat-exchange coil and thence back to said room heat-exchange coils during said reversed operation.

17. An air conditioning system for multi-room buildings having an interior and exterior zone comprising conditioning units located in air communication with respective rooms of said exterior zone, said units each including a heat-exchange coil and nozzle means; means for supplying primary air to said nozzle means for discharge through said units into said rooms at a sufiicient velocity to induce a flow of room air through said units and over said heat-exchange coils; a conditioner for treating said primary air and including first and second heateXchange coils; means for supplying outside air to said interior zone rooms; a conditioner for treating said outside air and including a heat-exchange coil; a refrigerating system for supplying chilled water to said room heatexchange coils, to said first primary air conditioner heat-exchange coil and to said outside air conditioner heat-exchange coil, said refrigerating system including a liquid cooled condenser; means for supplying heated condenser liquid to said second primary air conditioner heat-exchange coil; means for reversing the operation of said refrigerating system for supplying heated water to said first primary air conditioner heat-exchange coil; and means for directing Water from said room heat-exchange coils in a circuit through said outside air conditioner heat-exchange coil and thence back to said room heatexchange coils during said reversed operation.

References Cited in the file of this patent UNITED STATES PATENTS 2,200,215 Lewis May 7, 1940 2,363,294 Carrier Nov. 21, 1944 2,567,758 Ashley Sept. 11, 1951 2,715,317 Rhodes Aug. 16, 1955 2,755,637 Schordine July 24, 1956 2,796,740 McFarlan June 25, 1957