US2715514A

US2715514A - Air conditioning system

Info

Publication number: US2715514A
Application number: US245894A
Authority: US
Inventors: William S Stair
Original assignee: York Corp
Current assignee: York Corp
Priority date: 1951-09-10
Filing date: 1951-09-10
Publication date: 1955-08-16
Anticipated expiration: 1972-08-16

Description

Aug. 16, 1955 w. s. STAl-R AIR CONDITIONING SYSTEM 2 Sheets-Sheet 2 Filed Sept. 10 1951 FAN MOTO R.

3m 5. w m m M K M 0 K mo Rm PM M m 3 5 (Ittorncgs United States Patent 0 Am CONDITIONING SYSTEM William S. Stair, York, Pa., assignor to York Corporation, York, Pa., a corporation of Delaware Application September 10, 1951, Serial No. 245,894

3 Claims. (Cl. 257-3) This invention relates to a heating and cooling installation for ofiice buildings, hotels, apartment houses and the like.

Specifically, it concerns an installation which comprises a central circulating system for a liquid heat exchange medium. A central heater and a central cooler are provided whereby said medium may be selectively heated or cooled. The liquid passes through the liquid paths of a plurality of heat exchangers. One of these heat exchangers is included in each of a plurality of individual room units. These room units include reversible refrigerating apparatus.

This refrigerating apparatus includes a motor driven compressor, the above heat exchanger and a second heat exchanger, the first and second heat exchangers being connected to function interchangeably as a condenser and as an evaporator. Each of the room units also includes a fan whereby room air or a mixture of room air and fresh air is circulated in heat exchange relation with the second heat exchanger. Depending upon the manner in which the compressor and the two heat exchangers are connected, the units may operate to absorb heat from the circulated air and reject it to the circulated medium or they may absorb heat from the circulated medium and supply it to the circulated air.

During the summer the room units will be operating to absorb heat from the air. Under this condition, the central cooler is operated so that the medium is at a reduced temperature when it reaches the room units.

In the winter the room units are reversely conditioned so that heat is delivered to the circulated air. Under these conditions the heater is operated so that the circulated medium is supplied to the units at an elevated temperature.

Between seasons the load on the system may be unbalanced. Under these conditions the individual room units may act either to heat or to cool the circulated air, and the operation of each unit is independent of the operation of the other units throughout the building. During this time of the year, the circulated medium is supplied to room units at the same temperature as during the heating season.

The elevated temperature to which the medium is raised during the heating season and between seasons is not so high as would preclude operation of the room units as coolers. The safe operation of the units as coolers depends upon the condensers being adequately cooled by the circulated medium. The units are so designed as to capacity that they may be operated as coolers when the temperature of the circulated medium is equal to or less than the elevated temperature. This feature insures safe operation during the between seasons period of the year. A safety switch is provided to prevent operation of the compressor should the temperature of the circulated medium become excessive. Because the elevated temperature to which the circulated medium is raised during the heating season and between seasons is not high, appreciable quantities of low-level waste heat 2,715,514 Patented Aug. 16, 1955 from laundries, kitchens and similar sources in hotels, and apartment houses can be applied to the circulated medium to maximum advantage.

A system built according to this invention provides a single installation which is operable either to heat or to cool the building. It is also operable to heat or cool any particular room or rooms in the building independently of its operation in other rooms.

It will be seen that the system combines a heating system and individual room air conditioning units in a manner which alfords an installation which is very flexible in its operation. It is not necessary that the pipes in the circulating system be insulated. The refrigerating apparatus, when acting to heat the room, operates as a heat pump. This heat pump absorbs heat from the circulated medium which may be relatively cool and supplies heat to the room air at an elevated temperature. The heat absorbed from the circulated medium must be supplied from other sources such as gas, oil or coal. Hence, the system is particularly adapted to localities where costs of these fuels are relatively high and costs of electric power relatively low. Further reduction in normal electric power rates may be anticipated by virtue of the high annual load factor resulting from operation of the motor driven compressors during the heating season and between seasons, as well as during the summer for cooling only.

Figure 1 is a diagrammatic showing of a preferred embodiment of the invention;

Figure 2 is a diagrammatic showing of one of the room units;

Figure 3 is a diagram of a typical control circuit for one of the room units.

The closed circulating system comprises an expansion tank 11 located near the roof 12 of the building. The tank 11 is provided with a float controlled make-up connection 13 and a drain 14. Liquid passes from the tank 11 through the motor driven circulatory pump 15 through the connection 16 to the heater 17. After passing through the heater 17, the liquid flows through a manifold 18 to risers 19 and to the room units generally indicated at 21. The room units are connected in parallel between the risers 19 and return lines 22 through which the heat exchange liquid flows to the collector 23 and the cooling tower 24 located on the roof of the building. From the tower 24 the fluid returns to the expansion tank 11. A by-pass 25 extends between the collector 23 and the expansion tank 11. A manual valve 7 is interposed in the by-pass 25; another, 8, in the steam supply line; and a third, 9, in the line from the collector 23 to the cooling tower.

Flow through the bypass 25 is controlled by a pneumatically operated valve 26, as will be more fully described. The supply of steam to the heater 17 is controlled by a pneumatically operated valve 27 which is thermostatically controlled. Direct fired heating means, using any type of fuel, and a thermostatically actuated switch for its control may be substituted for heater 17 and steam valve 27. Because the temperature of the circulated medium during the heating season is far below that required in conventional hot water heating systems, maximum fuel economy is possible.

The thermostatic control system for the

valves

26 and 27 includes three

pneumatic thermostats

28, 29, and 31. The thermostat 28 has a branch line 32 connected to the thermostat 29. The branch line 33 of the thermostat 29 is connected to the pneumatic valve 27 and to the relay valve 34. The thermostat 28 is responsive to outdoor temperature sensed by the bulb 35. Thermostat 29 is operated in response to the temperature of the circulated medium leaving the heater 17. Thermostat 28 is a reverse-acting instrument and serves to readjust the control point of the thermostat 29 so that value the relay valve is opened and vents the branch line 36'of the thermostat 31. Thevalve 26 is ;open when the line 36 is vented. When the pressure-in ;the branch line 33 -reaches this predetermined value the valve 27 is opened. As long as the relay valve '34 is closed, the thermostat 31 controls the opening and closing of the valve=26. The thermostat 31 is responsive to the temperature of the circulated medium in-the tank 11 which is sensed by the bulb 37.

The thermostat 31 is active duringthe between seasons period-of the yearto maintain a constant temperature in the tank -'1- 1.' During'the cooling season the valve 26 will normally remain closed. 'Manual valve 7 can be closed at :this time.

As shown in Figure '2, the room units "21 include a motor driven compressor -38, a first heat exchanger '39, and a second heat exchanger 41. A fan 42 draws air from the room air inlet 43 and the fresh air inlet 4,4 and circulates it in heat exchange relation with the first heat exchanger 39. The proportion of fresh and room air circulated by the fan ,42 is determined by the damper 45. This damper is manually operated in the illustrated embodiment, 'but' could be operated by a thermostatically controlled motor. Such .motors and their controls are well 'known in the art;

The heat exchanger 39 is made in two sections, 39 and '39". When theheat exchanger39 is serving as a condenser, as will be more fully described, both sections 39' and 39 are effectively used as-heat exchange surfaces. During operation of this exchanger as an'evaporator the lower-section "39 carries the heat exchange load while upper section '39 serves only. as a part of the suction ,line through which vaporized refrigerant is re turned to the compressor. This arrangement provides the added heat exchange surface which is required when the coil 39 is operated as an air cooled condenser.

"I he second heat exchanger 41 maybe of the double pipe type. The liquid heat exchange medium from the closed circulatory system flows through the inner pipe indicated in dotted lines, and refrigerant passes through theannular space; a

A valve 46 controls the direction of flow of refrigerant through the heatexchangers 39 and 4 1. In the positionillustrated, compressed refrigerant vapors flow from the compressor discharge 47 to the heat exchanger 39 which isoperating as a condenser. Heat exchangerfll V isoperating as an evaporator. Valve 46 may be shifted so as to discharge compressed refrigerant vapor totheiheat exchanger 41 while drawing gas from the exchanger 39 through the suction'line 48. The function of the two heat exchangers may thus be interchanged. Expansion of the liquid refrigerant is controlled by a restrictor tube 49, although other expansion controlling means can he used.

7 ing control switches 54 and 55. The switch 53 is thermostatically operated in response to room temperature and is effective to open the circuit when the room temperature falls below a predetermined minimum. The

switch 54 is -,a thermostatically controlled switch and is eflfective to open the circuit when the room temperature exceeds a predetermined maximum. Switch 55 responds to temperature .of the circulated liquid leaving the heater 1 7 and shuts offthe compressor when it exceeds a predetermined It is ,a .safety co ntrol.

Operation During the heating season valve 7 is opened and valve 9 may be closed so that the by-pass 25 between the col-. lector 23 and the tank 11 is open and the cooling tower 24 is idle. Valve 8 is opened and steam is supplied to the heater 17 so that the temperature of liquid supplied to the system is elevated .to .the desired value. When the room units 21 are arranged as shown in Figure 2, the heat exchanger 39 acts as a condenser and heat exchanger ,il .acts .as an evaporator. Thus .it will be'seen that 'the unit acts as a heat pump to absorb heat from the circulated medium and deliver it to the room air.

During -the summer, when cooling is desired, the valve 46 is moved to the positionin which the heat exchanger 41 functions as a condenser and exchanger 39 functions as an evaporator. The switch 52 is positioned'so that the summercontrols are operating. Valve 8 is closed and t ea e 1 is shu dhwh- T Y-Psss .2 m he hssd lh ihsr l 7- a Y s hu ed s as to cause the circulated medium to pass through the coolhe Q s 4- h rj om un t un l5 .,Ql1 i QP operate a a hhv fihg lh i h r s u h Wat c le shds s is id ah -hs s :i rs ssd fli isn ma be realized. I V l i 7 i I .Bs wssh th summe an win e so the lo d .0 the hs llatiq k h s h 1ahssd be a e for e am l lhhih h ths hQ th s swih he @9 w i those I the south are Warm. The room unitsean be independently stth s hrhs th @9 asth nc upa t hs eo lm y d sir hi t n is ssha lsd th s t n of the .-.D. .g t e h n is hsqh th f i er n ppar ms a 3 h??? P P.- .I' she hi bsor a a r lativ r. a shd l v ns ata nc high r temperaturehs s rs hsni qu a ssim i m need uoth snppl'ed at as high a .te p

V T si s n un n latsd P n results ins ehs sra l av h i sta ation costs- What is claimed is: a 1. A heating and cooling installation for buildings ompr sins hfiqm n tion, a cir ul t g system through which ,a heat exchange medium is circulated, the system including ,means to cirqulaterthemedium, a cooler operable to cool said medium, a heater operable to {heat said medium, said heaterand cooler being selectively operable,

and a supply riser and .a return riser; a plurality of independently operable ;room ;units, .each unit including reversible refrigerating apparatus, said apparatus including ,flifi TSI and second heat exchanger .operatively lDtCI". connected and interchangeably efiectiverespectivelyas a pathzhavingjm sends directly connected .to said supply riser and to said return riser, means to circulate air.to be.

suppliedato the. :room in heat exchange relation .with the othenheat exchangerin each unit; and means controlling the temperatureof. the circulatedmedium supplied to the heatexchangersthrough whichcit flows, said temperature beingsuchthatthe liquid will serve as a source of heatin thosev exchangers operating as a refrigerant evaporator but less .than themaximum permissible for it to -act as a cool- 7 ing medium in thoseheat exchangers which areoperating as refrigerant. condensers.

2. The method of conditioning airin a building which consists incirculating a-liquid heat exchange medium to a plurality of heat exchangers, connectedinparallelflowrelation, andlselectively .and individually operating said heat exchangers as the heat absorbing or heat'dissipating' eratnreas is characteristic of 7 t when t the maximum is less than the maximum permissible for cooling any of the heat dissipating surfaces which it contacts and circulating air in heat exchange relation with the other heat exchange surfaces of said units.

3. A heating and cooling installation for buildings comprising in combination, a circulating system through which a heat exchange medium is circulated, the system including means to circulate the medium, a cooler operable to cool said medium, a heater operable to heat said medium, said heater and cooler being selectively operable, and a supply header and a plurality of supply risers connected in parallel flow relation therewith and a return header and a plurality of return risers connected in parallel flow relation therewith; a plurality of independently operable room units, each unit including reversible refrigerating apparatus, said apparatus including a first and second heat exchanger operatively interconnected and interchangeably efiective respectively as a refrigerant evaporator and as a refrigerant condenser or respectively as a refrigerant condenser and refrigerant evaporator, one of said heat exchangers in each unit having a path for circulated heat exchange medium, said path having its ends directly connected to one of the aforesaid supply risers and to one of the aforesaid return risers, means to circulate air to be supplied to the room in heat exchange relation with the other heat exchanger in each unit; and means controlling the temperature of the circulated medium supplied to the heat exchangers through which it flows, said temperature being such that the liquid will serve as a source of heat in those exchangers operating as a refrigerant evaporator but less than the maximum permissible for it to act as a cooling medium in those heat exchangers which are operating as refrigerant condensers.

References Cited in the file of this patent UNITED STATES PATENTS Re. 22,100 Brace et al. May 26, 1942 2,260,887 Dasher Oct. 28, 1941 2,401,890 Smith et al. June 11, 1946 2,441,885 Kemler et al. May 18, 1948 2,513,373 Sporn et al July 4, 1950