US2105882A - Mr conditioning system - Google Patents

Mr conditioning system Download PDF

Info

Publication number
US2105882A
US2105882A US2105882DA US2105882A US 2105882 A US2105882 A US 2105882A US 2105882D A US2105882D A US 2105882DA US 2105882 A US2105882 A US 2105882A
Authority
US
United States
Prior art keywords
air
coils
conditioner
temperature
conditioning
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
Publication date
Application granted granted Critical
Publication of US2105882A publication Critical patent/US2105882A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28HEAT EXCHANGE IN GENERAL
    • F28FDETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F13/00Arrangements for modifying heat-transfer, e.g. increasing, decreasing
    • F28F13/06Arrangements for modifying heat-transfer, e.g. increasing, decreasing by affecting the pattern of flow of the heat-exchange media

Definitions

  • IlllllllllllllllllllllllllllllllllIIIIIIIIIIIIIII A a IlllllllllllllllIIllIllllllIIIIIIIIIIIIIII) llllllIIllllllllllllllIIIIIIIIIIIIIIIIII Q :Illllllllllllllllll INVEN TOR. WALfeR L fif/SMER BY g A TTORNE Y.
  • This invention relates to methods of and means for conditioning the atmospheres of enclosures.
  • the general object of the invention is to provide a system for conditioning the air of an enclosure wherein people congregate, in which all air handled by the system is treated for purposes of temperature and humidity regulation, but which assures delivery to the enclosure of air at a comfortable temperature and proper relative 1o humidity.
  • s i. e., substantially saturated. Since this air cannotsafely be introduced directly into the room or enclosure constituting the conditioned area, it must be reheated.
  • the reheating is ordinarily accomplished by adding to the conditioned air a volume of air from the enclosure under proper regulation. As a result, a tempered mixture is formed at a comfortable temperature higher than that of the conditioned air and at a proper relative humidity, lower than that of the conditioned air.
  • 'A feature of this invention resides in the conditioning of all instead of part of the air handled by the air conditioning system, wherein all air passes over cooling surfaces, so arranged that the air leaving the surfaces is suitable for introduction to the enclosure, i. e., is at a temperature substantially above the dew point required for dehumidification and at a relative humidity substantially below saturation.
  • applicant utilizes a plurality of cooling surfaces, one surface covering the entire cross-sectional area of the conditioner casing, others covering desired portions of the cross-sectional area, predetermined in accordance with the results do- 45 sired.
  • one section of the cooling surface will cover the entire cross-section of the apparatus; one may cover only two-thirds; a third only one-third of the entire cross-section, and so Another feature of the invention, therefore, re-
  • a further feature provides for feeding under suitable control either a cooling medium under summer conditions or a heating medium under winter conditions to a series of coils serving to cool and dehumidify or heat an air stream passing through the apparatus, responsive to load conditions afiecting the conditioned area.
  • Another feature provides for washing and, under desired conditions, humidifying the air to assure dust and dirt precipitation as well as humidification control, whenever such treatment of the air may be desirable.
  • Fig. 1 is a diagrammatic view of an air conditioning system, fragmentarily illustrated, in which applicant's conditioning elements, of varying capacity and covering varying cross-sectional areas of the same conditioner, are employed, and
  • Fig. 2 is a diagrammatic fragmentary view of a modified form of coil arrangement in which coils of varying size are employed, the coils being arranged, as in Fig. 1, to cover different crosssectional areas of the same conditioner.
  • numeral 3 designates an enclosure such as a theatre, store, railroad car, or other area to be conditioned. Air is delivered to the enclosure from conditioner 4 by fan 5 through one or more ducts 6; and air is returned from the enclosure for reconditioning through return duct 1. Outdoor air through intake 8 under control of dampers 9 and the return air under control of dampers I0, enter the conditioner 4 where the outdoor air and/or return air will be conditioned as to temperature and humidity. Dampers 9 and I0 may be controlled manually or suitably operated automatically.
  • dampers 9 will never be permitted to fully close, so that a minimum volume of outdoor air will always be admitted, suflicient air contacting therewith and produce a desired conditioning medium is returned from the coils to said source through return conduit I8.
  • the refrigerant or conditioning medium supplied to the coils is suitably reduced in temperature under summer operating conditions so that the temperature of the coil surfaces will be capable of dehumidifying low temperature.
  • cold brine or Water will be supplied through conduit II, or, if desired, a chemical refrigerant of suitable character will be fed into the coils and cool the air contacting with the coils by direct expansion.
  • the fluid will preferably be refrigerated water, under summer conditions, and the same supply conduit Il may feed the sprays I9.
  • Eliminators 20 remove entrained moisture from the air.
  • the reheater 2i is used, under winter operating conditions and is fed with steam or other heating fluid from any suitable source of supply.
  • the coils H, I2, I3, It, I and I5 are preferably made of light weight metal of high conductivity having extended surfaces for promoting heat transfer.
  • Coils II and I2 extend from wall 22 of the conditioner casing into and cover about one third of the cross-sectional area of the conditioner.
  • Coils I3 and Id extend into about two-thirds of the distance between walls '22 and 23 of the case.
  • Coils I5 and I6 extend the full distance between the walls 22,and 23 ofthe casing and cover the whole cross-sectional area of the casingl As a'result, if the volume of air passing through the conditioner at any one time be considered a unit, then substantially one-third A of the unit of air will contact with coils II and I2; the same third and an additional third will contact with coils I3 and I 4; and the whole unit will contact with coils I5 and 5.. Obviously, the first third, which contacts with all coils will be treated to a greater degree than the third which contacts only with coils I 3I 6 and the third which contacts'only with coils I5 and I6 will be aifected least of all.
  • the second third may be reduced, for example, to a temperature of 68 degrees and a relative humidity practically saturated, and the third third may be reduced, for example, to a temperature of 81 degrees and a relative humidity much less than saturated.
  • the final temperature of the air stream at the discharge end of the conditioner will be, for exand Ila at. pounds.
  • the introduction of this air within the enclosure will make for desired conditions, which neither third, if alone introduced, would produce, even if cir culation requirements were entirely disregarded.
  • the sprays I9 may be used for cleaning and huinidifying the air under winter conditions.
  • the water fed to the sprays will be at a temperature suitable for humidification purposes.
  • the coils II-IB in winter, may be supplied with a heating medium, if desired, but the arrangement of coils, as heretofore described, has its primary advantages under summer conditions, when it may condition all air handled by the system yet deliver the air at a comfortable temperature and proper relative humidity.
  • thermostat E i responsive to temperature changes in the enclosure, may be provided to control the admission of refrigerant to the coils.
  • valves Ila, I2a, I3a, I la, I51: and Mia regulate the admission of refrigerant or conditioning fluid to respective coils II, I2, I3, M1,. I5 and I6.
  • thermostat 26 causes valve I6a to open first. This valve may.
  • the thermostat will cause the valves sucditions all coils will be receiving refrigerant. As load conditions decrease, the coils will successively be cut out in reverse order.
  • valve 25 which may be controlled manually or automatically in response to changes in humidity in the enclosure. Normally, this valve is closed during the summer or dehumidifying periods. Under winter conditions, thermostat 24 controls the admission of steam to reheater 2
  • are of various sizes and capacities.
  • coils 28 and 29 extend across the whole cross-sectional area of conditioner 4, as do coils 30 and 3
  • Coils 26 and 21 are not only of different size and hence, of different capacity than the other coils, but extend but partially across the conditioner. Therefore, applicant may vary coil sizes, present coils of varying surface and capacity, and utilize coils extending over the whole or part of the cross-sectional area of the conditioner, thereby producing a desired final condition of temperature and relative humidity, due to varying effects of the different coils upon the air stream flowing through the conditioner.
  • the resistances may he designed to afford resistance equal to, less than, or greater than that provided by adjacent coils covering equivalent cross-sectional area,
  • a conditioner having an air inlet, an air outlet, tempering coils between the inlet and outlet, one of said coils covering a certain cross-sectional area of the conditioner, other of said coils covering different cross-sectional areas of the conditioner, means in addition to said coils to equalize the resistance to air flow through all parts of the cross-sectional area of the conditioner.
  • a conditioner having an airinlet and an air outiet, a series of tempering coils within said conditioner between said inlet and said outlet, means for passing a stream of air through said conditioner from said inlet to said outlet, said coils being arranged so that one portion of said air stream will Contact with a relatively great amount of coil surface and so that another portion of said air, stream will contact with a lesser amount of coil surface, and means in addition to said coils for regulating the resistance to the flow through said conditioner of different portions of the air stream.
  • a conditioner having an air inlet and an air outlet, a plurality of tempering elements within said.conditioner between said inlet and said outlet, different of said elements covering different portions of the cross sectional area of said conditioner, and means in addition to said elements for regulating the resistance to air flow through difierent portions of the cross sectional area of said conditioner.

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Central Air Conditioning (AREA)

Description

Jan. 18, 1938. w. L. FLEISHER 2,105,882
AIR CONDITIONING SYSTEM Filed Nov. "6, 1934 S i x U lIIIIIllllllllllllIlllllIIIIIIIIIIIIIIIIIIIIII,
i IlllllllllllllllllllllllllllIIIIIIIIIIIIIIIIII A a IlllllllllllllllIIllIllllIIIIIIIIIIIIIIIIIIIII) llllllIIllllllllllllllIIIIIIIIIIIIIIIIIIIIIIII Q :Illllllllllllll INVEN TOR. WALfeR L fif/SMER BY g A TTORNE Y.
Patente Jan. 18, 1938 4 Claims.
This invention relates to methods of and means for conditioning the atmospheres of enclosures.
The general object of the invention is to provide a system for conditioning the air of an enclosure wherein people congregate, in which all air handled by the system is treated for purposes of temperature and humidity regulation, but which assures delivery to the enclosure of air at a comfortable temperature and proper relative 1o humidity.
' In accepted air conditioning practice, it is usual to condition a volume of air by passing the air through a cold water spray or over surface coolers through which a refrigerating medium is cir- 13 culated. The treated air is thereby reduced to a temperature below its dewpoint, and its excessive absolute humidity precipitated. The air is then too cold for comfort, and also, at a relative humidity of about one hundred per cent,
s, i. e., substantially saturated. Since this air cannotsafely be introduced directly into the room or enclosure constituting the conditioned area, it must be reheated. The reheating is ordinarily accomplished by adding to the conditioned air a volume of air from the enclosure under proper regulation. As a result, a tempered mixture is formed at a comfortable temperature higher than that of the conditioned air and at a proper relative humidity, lower than that of the conditioned air.
'A feature of this invention resides in the conditioning of all instead of part of the air handled by the air conditioning system, wherein all air passes over cooling surfaces, so arranged that the air leaving the surfaces is suitable for introduction to the enclosure, i. e., is at a temperature substantially above the dew point required for dehumidification and at a relative humidity substantially below saturation. To achieve this re- 40 suit, applicant utilizes a plurality of cooling surfaces, one surface covering the entire cross-sectional area of the conditioner casing, others covering desired portions of the cross-sectional area, predetermined in accordance with the results do- 45 sired. Thus, one section of the cooling surface will cover the entire cross-section of the apparatus; one may cover only two-thirds; a third only one-third of the entire cross-section, and so Another feature of the invention, therefore, re-
sides in the provision of cooling surfaces, adapted to condition to varying degrees different proportions of a total volume of air handled by a unitary air conditioning apparatus. Also, by =5 providing a combination of surface cooler units covering different cross-sectional areas of the same apparatus through which all the air flows, a varying resistance to the fiow of air is provided at difierent points in the apparatus. Thus, the air stream is automatically proportioned, so that different portions contact with the difierent cooler elements, and this makes for a simple method of conditioning to different degrees, different portions of the one volume of air.
A further feature provides for feeding under suitable control either a cooling medium under summer conditions or a heating medium under winter conditions to a series of coils serving to cool and dehumidify or heat an air stream passing through the apparatus, responsive to load conditions afiecting the conditioned area.
Another feature provides for washing and, under desired conditions, humidifying the air to assure dust and dirt precipitation as well as humidification control, whenever such treatment of the air may be desirable.
Further advantages flowing from simplicity in construction, ease and economy of operation, and effectiveness of control, will be apparent from the following description of a typical form of carrying out the invention to be read in connection with the accompanying illustrative drawing, in
which:
Fig. 1 is a diagrammatic view of an air conditioning system, fragmentarily illustrated, in which applicant's conditioning elements, of varying capacity and covering varying cross-sectional areas of the same conditioner, are employed, and
Fig. 2 is a diagrammatic fragmentary view of a modified form of coil arrangement in which coils of varying size are employed, the coils being arranged, as in Fig. 1, to cover different crosssectional areas of the same conditioner.
Considering the drawing, similar designations referring to similar parts, numeral 3 designates an enclosure such as a theatre, store, railroad car, or other area to be conditioned. Air is delivered to the enclosure from conditioner 4 by fan 5 through one or more ducts 6; and air is returned from the enclosure for reconditioning through return duct 1. Outdoor air through intake 8 under control of dampers 9 and the return air under control of dampers I0, enter the conditioner 4 where the outdoor air and/or return air will be conditioned as to temperature and humidity. Dampers 9 and I0 may be controlled manually or suitably operated automatically. Usually, however, dampers 9 will never be permitted to fully close, so that a minimum volume of outdoor air will always be admitted, suflicient air contacting therewith and produce a desired conditioning medium is returned from the coils to said source through return conduit I8. While no refrigeration apparatus or the like is illustrated, it will be understood that the refrigerant or conditioning medium supplied to the coils is suitably reduced in temperature under summer operating conditions so that the temperature of the coil surfaces will be capable of dehumidifying low temperature. Thus, cold brine or Water will be supplied through conduit II, or, if desired, a chemical refrigerant of suitable character will be fed into the coils and cool the air contacting with the coils by direct expansion.
In Fig. 1, the fluid will preferably be refrigerated water, under summer conditions, and the same supply conduit Il may feed the sprays I9. Eliminators 20 remove entrained moisture from the air. The reheater 2i is used, under winter operating conditions and is fed with steam or other heating fluid from any suitable source of supply.
The coils H, I2, I3, It, I and I5 are preferably made of light weight metal of high conductivity having extended surfaces for promoting heat transfer. Coils II and I2 extend from wall 22 of the conditioner casing into and cover about one third of the cross-sectional area of the conditioner. Coils I3 and Id extend into about two-thirds of the distance between walls '22 and 23 of the case. Coils I5 and I6 extend the full distance between the walls 22,and 23 ofthe casing and cover the whole cross-sectional area of the casingl As a'result, if the volume of air passing through the conditioner at any one time be considered a unit, then substantially one-third A of the unit of air will contact with coils II and I2; the same third and an additional third will contact with coils I3 and I 4; and the whole unit will contact with coils I5 and 5.. Obviously, the first third, which contacts with all coils will be treated to a greater degree than the third which contacts only with coils I 3I 6 and the third which contacts'only with coils I5 and I6 will be aifected least of all. 'I'hus,-under summer operating conditions, with refrigerant at a prescribed low temperature circulating through the coils, and depending upon the relative amount of surface in each of the coils, some of the air will be intensively conditioned to a desired low dewpoint, whereas other portions of the air will be conditioned to a lesser degree or only relatively slightly affected. ditioned air will, therefore, be augmented in volume by the other air, and reheated to a higher desired temperature. For example, with outside conditions at 95 degrees dry bulb and '78 degrees wet bulb, the first third in the method described in connection with Fig. 1 may be reduced to 55 degrees dry bulb, one hundred per cent relative humidity. The second third may be reduced, for example, to a temperature of 68 degrees and a relative humidity practically saturated, and the third third may be reduced, for example, to a temperature of 81 degrees and a relative humidity much less than saturated. As a result, the final temperature of the air stream at the discharge end of the conditioner will be, for exand Ila at. pounds.
The intensively conample, 68 degrees R, which is much-higher than 55 degrees, the, temperature of the first third after conditioning, and at a relative humidity appreciably less than one hundred per cent. The introduction of this air within the enclosure will make for desired conditions, which neither third, if alone introduced, would produce, even if cir culation requirements were entirely disregarded. The sprays I9 may be used for cleaning and huinidifying the air under winter conditions. The water fed to the sprays will be at a temperature suitable for humidification purposes. The coils II-IB, in winter, may be supplied with a heating medium, if desired, but the arrangement of coils, as heretofore described, has its primary advantages under summer conditions, when it may condition all air handled by the system yet deliver the air at a comfortable temperature and proper relative humidity.
Although the coil arrangement may be manually controlled, a thermostat E i, responsive to temperature changes in the enclosure, may be provided to control the admission of refrigerant to the coils. Thus, valves Ila, I2a, I3a, I la, I51: and Mia. regulate the admission of refrigerant or conditioning fluid to respective coils II, I2, I3, M1,. I5 and I6. Under summer operating conditions, whenever temperature conditions in the enclosure rise above a prescribed point, thermostat 26 causes valve I6a to open first. This valve may. operate, for example, at 5- pounds air pressure, whereas I511 will operate at 7 pounds, Ila at 9 pounds, I3a at 11 pounds, I2a at 13 pounds As more cooling is required, the thermostat will cause the valves sucditions all coils will be receiving refrigerant. As load conditions decrease, the coils will successively be cut out in reverse order.
The admission of conditioning medium to the sprays is controlled by valve 25, which may be controlled manually or automatically in response to changes in humidity in the enclosure. Normally, this valve is closed during the summer or dehumidifying periods. Under winter conditions, thermostat 24 controls the admission of steam to reheater 2|, and, if desired, may control the admission of heating fluid to the coils in the same manner as itcontrols the admission of refrigerant under summer'conditions.
In Fig. 2, the coils 26, 21, 28,29, and 3| are of various sizes and capacities. Thus, while coils 28 and 29 extend across the whole cross-sectional area of conditioner 4, as do coils 30 and 3|, they present less surface and are of smaller capacity than coils 30, 3| and hence, have less eifect upon a stream of air passing through the conditioner. Coils 26 and 21 are not only of different size and hence, of different capacity than the other coils, but extend but partially across the conditioner. Therefore, applicant may vary coil sizes, present coils of varying surface and capacity, and utilize coils extending over the whole or part of the cross-sectional area of the conditioner, thereby producing a desired final condition of temperature and relative humidity, due to varying effects of the different coils upon the air stream flowing through the conditioner.
If it is desired to have the resistance to passage of air through the conditionersubstantially the same at every point throughout the crosssectional area thereof, resistances such as 32 and 33 of Fig.1 and 34 of Fig. 2, comprising, for example, screens of suitable mesh, perforated cessively to open to admit refrigerant and increase I v the total cooling effect, until under peak load conaioaeea plates, or the like, may "he-provided and posi-= tioned in portions of the conditioner not provided with coils. The resistances may he designed to afford resistance equal to, less than, or greater than that provided by adjacent coils covering equivalent cross-sectional area,
Although coils are shown, it is apparent that any equivalent arrangement of equivaient conditioning means may be utilized to achieve equivalent results.
Since certain changes in carrying out the above process and in the constructions set forth, which embody the invention, may be made without departing from. its scope, it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in-a limiting sense.
I claim:
i. In a system of air conditioning, a conditioner having an air inlet, an air outlet, tempering coils between the inlet and outlet, one of said coils covering a certain cross-sectional area of the conditioner, other of said coils covering different cross-sectional areas of the conditioner, means in addition to said coils to equalize the resistance to air flow through all parts of the cross-sectional area of the conditioner.
2. In an air conditioning apparatus, a conditioner having an air inlet and an air outlet, tempering coils within said conditioner between said inlet and said outlet, difierent of said coils covering different portions of the cross-sectional area of said conditioner, and means in addition to said coils for regulating the resistance to air flow through different portions of the cross=sectional area of said conditioner.
3. In an air conditioning apparatus, a conditioner having an airinlet and an air outiet, a series of tempering coils within said conditioner between said inlet and said outlet, means for passing a stream of air through said conditioner from said inlet to said outlet, said coils being arranged so that one portion of said air stream will Contact with a relatively great amount of coil surface and so that another portion of said air, stream will contact with a lesser amount of coil surface, and means in addition to said coils for regulating the resistance to the flow through said conditioner of different portions of the air stream.
4. In an air conditioning apparatus, a conditioner having an air inlet and an air outlet, a plurality of tempering elements within said.conditioner between said inlet and said outlet, different of said elements covering different portions of the cross sectional area of said conditioner, and means in addition to said elements for regulating the resistance to air flow through difierent portions of the cross sectional area of said conditioner.
WALTER L. FLEISHER.
US2105882D Mr conditioning system Expired - Lifetime US2105882A (en)

Publications (1)

Publication Number Publication Date
US2105882A true US2105882A (en) 1938-01-18

Family

ID=3429191

Family Applications (1)

Application Number Title Priority Date Filing Date
US2105882D Expired - Lifetime US2105882A (en) Mr conditioning system

Country Status (1)

Country Link
US (1) US2105882A (en)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3183966A (en) * 1961-07-31 1965-05-18 W M Wilson Co Inc Control system
US3195622A (en) * 1961-01-23 1965-07-20 Itt Lateral valve control for air conditioning equipment
US3345829A (en) * 1966-04-20 1967-10-10 Henry J Hall Method and means for controlling the condensation of vapors under a varying ambient
US4191027A (en) * 1976-07-29 1980-03-04 Kabushiki Kaisah Maekawa Seisakusho Apparatus for cooling brine
US4494596A (en) * 1980-05-16 1985-01-22 Haden Schweitzer Corporation Method and apparatus for conditioning air temperature and humidity
US4579163A (en) * 1983-03-29 1986-04-01 Maendel Jonathan P Heat exchanger core and air flow control
US5108475A (en) * 1991-01-28 1992-04-28 Venturedyne, Ltd. Solvent recovery system with means for reducing input energy
US6116033A (en) * 1997-12-10 2000-09-12 Nec Corporation Outside air conditioner
US20040247500A1 (en) * 2001-09-04 2004-12-09 Robert Ashe Temperature control system

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3195622A (en) * 1961-01-23 1965-07-20 Itt Lateral valve control for air conditioning equipment
US3183966A (en) * 1961-07-31 1965-05-18 W M Wilson Co Inc Control system
US3345829A (en) * 1966-04-20 1967-10-10 Henry J Hall Method and means for controlling the condensation of vapors under a varying ambient
US4191027A (en) * 1976-07-29 1980-03-04 Kabushiki Kaisah Maekawa Seisakusho Apparatus for cooling brine
US4494596A (en) * 1980-05-16 1985-01-22 Haden Schweitzer Corporation Method and apparatus for conditioning air temperature and humidity
US4579163A (en) * 1983-03-29 1986-04-01 Maendel Jonathan P Heat exchanger core and air flow control
US5108475A (en) * 1991-01-28 1992-04-28 Venturedyne, Ltd. Solvent recovery system with means for reducing input energy
US6116033A (en) * 1997-12-10 2000-09-12 Nec Corporation Outside air conditioner
US20040247500A1 (en) * 2001-09-04 2004-12-09 Robert Ashe Temperature control system
US20080173439A1 (en) * 2001-09-04 2008-07-24 Ashe Morris Ltd Temperature control system
US7767156B2 (en) 2001-09-04 2010-08-03 Ashe Morris Ltd Temperature control system

Similar Documents

Publication Publication Date Title
US2327664A (en) Method of and apparatus for air conditioning
US1837798A (en) Apparatus for conditioning air
US1949735A (en) Apparatus for ventilating and conditioning buildings
US3024008A (en) Three-pipe air conditioning systems
US2147248A (en) Adsorption system of air conditioning
JP4651377B2 (en) Air conditioning system
US2105882A (en) Mr conditioning system
US2712927A (en) Air conditioning methods
US3277954A (en) System for producing conditioned air
US2257485A (en) Air conditioning system
US2159276A (en) Air conditioning system
US2236190A (en) Air conditioning apparatus
US3350892A (en) Two-stage air conditioning system
US1837797A (en) Method and apparatus for conditioning air
US2123742A (en) Air conditioning
US2058919A (en) Air conditioning apparatus
US1846875A (en) Air conditioning
US2105692A (en) Air conditioning apparatus
US2256940A (en) Air conditioning
US2044352A (en) Mr conbitioning system
US2256374A (en) Method of humidifying air
US1913659A (en) Air conditioning
US2124290A (en) Air conditioning system
US1849061A (en) Air conditioning equipment
US2001704A (en) Apparatus for cooling and ventilating buildings