US2078295A - Piped air-conditioning and heating - Google Patents

Description

April 27, 1937. c. J. THATCHER 2,073,295 I PIPED AIR CONDITIONING AND HEATING SYSTEM Filed March 21, 1936 2 Sheets-Sheet 1 IIIIIIIIIIIIIIIIII 1/104 INVENTOR CHA/awd. THATCHER 1' 'W fi l I w m w ATTORN YJ A ril 27, 1937. c. .1. THATCHER PIPED AIR CONDITIONING AND HEATING SYSTEM Filed March 21, 1936 2 Sheets-Sheet 2 INVENTOL M mflw rm o n w a A 0 Patented Apr. 27, 1937 I UNITED STATES PI PED AIR-CONDITIONING AND HEATING SYSTEM Charles J. Thatcher, New York, N. Y.

Application March 21,

18 Claims.

This invention relates to a heat-exchange system designed to control the temperature of enclosed air spaces, and more particularly to a central heating system through pipes, which, by valve manipulation, may be temporarily converted into a cooling and general air-conditioning system for theatmosphere of rooms whenever climatic conditions make such conversion desirable.

The invention is concerned more especially with steam and hot-water heating equipment which is already installed; for example in exista ing large buildings such as hotels, ofiice buildings, and larger residences. In such structures the problem of either or both cooling and dehumidifying the air in warm weather does not admit of practical solution by the installation in the walls of the structure of cold-air ducts, new lines of pipes, etc. Such installations are pro- 20 hibitively expensive and troublesome in the case of existing structures. Moreover, the conduction of the usual gaseous or highly volatile refrigerants through the existing' pipe' lines is not feasible, and is beginning to "be generally prohibited by municipal'ordinances because of the dangers involved.

Experience has shown alsoithatthe cooling of.

a large number of rooms in such buildings-during the-usual short season of warm 'weather -i."e.,

tained cabinet units-for air-conditioning ineach room is not economically practicable. For, when there is added to the original high purchase price of such units, the cost of connections of each unit to power lines, drainage systems, fresh-air intakes, eta, plus the cost of more or less con- 7 stant servicing by licensed operators of a large number of such complicated units. the total expense of widespread summer comfort cooling in this way. is far more than the general public will pay. I

iThere is, therefore, =no known system by w hich :an, or any desired substantiallproportion, of the 45 many; rooms in large existing structures can be equipped for air-conditioning in warm weather except at prohibitive expense.

In order to bring the installation cost,of a system for general air-conditioning of large structures down to feasible limits, it appears to be necessary to combine it with the existing heating system; and no refrigerant other than compressed air for the reasons above stated'is safe or permitted for use therein. Although this me- 55 dium is less efficient than other refrigerants, it

.heat interchange units and lines of an existing heating system from June tofSeptember-'-by installing self-con: .1

1936, Serial No. 70,019 R (Cl. 257-8) 8 P m has been found that by the mprovem'e'nts of this invention the higher power cost is much more than offset by the diminished cost and facility or installation of suitable equipment, and the consequent greatly reduced amortizationand 5 interest charges.

The present invention has for an object, therefore, the provision of a means for so supplementing already installed heating systems, at a low initial cost, that the same may be employed dur- 1 ing the warm season of the year to cool, filter and dehumidify the atmosphere of rooms on those days when climatic conditions make such air-conditioning desirable.

A further object of the invention is to make it 15 practicable and economical to use compressed air as the refrigerant in air-conditioning the rooms of structures of the class specified.

Another object of the invention is the provision of apparatus of a rugged and simple character, the installation of which may be accomplished with a minimum of labor and alterations 01' existing heating installations, and without necessitating, in any way, the marring of walls and-floors.

Still another 'objectof theinvention is to make use, when desirable, of the usual radiators. or

the connected pipe for the disposal of condensed water resulting from dehu- 30 'midiflcation, and also to eliminate condensation of water vapor and frosting on the conducting pipes between compressor and radiating units or 'on the units themselves.

In carrying out the invention, an air compr n 35 sor is associated with the usual type of steainfor hot-water heating systems. These .systems'ins variably include a plurality of variously disposed heat exchange units and a central remote heat-' ing plant connected by pipelines therewith. In 4% accordance with the present invention, an aircompressor is installed at or near such central heating plant and is arranged to be connected to the pipe lines of the heating plant so as to convey compressed air instead of steam, when desired, tothe desired heat-exchange units. The heat of compression may first be removed thereat, as by partial adiabatic expansion, approximately to the temperature of the ambient air; and then, contrary to prior proposals, the major expansion and refrigeration is delayed to the actual point of use. Since this compressed air may thus be conveyed through the pipe lines at atmospheric or higher temperatures, no condensation of moisture from the air surrounding such can any frosting occur thereon.

To this end, individual, small expansion elements are associated with the respective heatexchange units or radiators for cooling the compressed air to the desired point, by adiabatic expansion, for eventual delivery into a radiator. Just prior to or at the point of such delivery, however, the chilled air is mixed with an appreciably greater proportion of the ambient warm and humid air from the rooms to be cooled, the chilledmixture being then introduced into a radiator, where excess moisture is condensed and deposited.

By this novel expedient, condensation of the water vapor contained in the humid, warm air of rooms is restricted to the interior of already installed radiators; and from these the resulting water is subsequently discharged through the return pipesin the usual manner and by the expedients provided for this purpose insuch heating systems. The air thus conditioned is discharged from the radiator into the surrounding space; or it may first be directed downwardly over the unit, so as to bathe the exterior walls of the radiator with cooled, dried air to prevent condensation of'moisture thereon, and to maintain a layer of cool, dried air in the lower levels of the room.

The accompanying drawing Fig. 1 shows, more or less diagrammatically, a standard heating installation modified in accordance with the invention 50 as to be convertible for cooling and general conditioning of air when climatic conditions make such change-over desirable. Fig. 2 is a transverse vertical section through the central plane of an expansion element and includes the blower, filters and other parts assembled therewith. Fig. 3 is an elevation of the assembled element showing the side adjacent to the radiator. Fig. 4 is a. horizontal section on the line 4--4 of Fig. 2 looking in the direction of the arrows. Fig. 5 is a detail elevation of the cam wheel which actuates the inlet valve of the expansion element; As indicated, l0 designates a suitable boiler,for example, of a steam-heating system including the steam main H for delivering steam to various heatexchange units or radiators l2, l2, etc., together with a return pipe l3 and the usual fittings and valves associated with such system including, in this particular embodiment, a sylphon valve l4 associated with each of the radiators to insure drainage of any water of condensation in a radiator.

In accordance with the invention, provision is made to disconnect or by-pass, temporarily, the boiler plant and associate with the remaining portion of the heating system an air-compressor plant. Thus, the said plant may comprise a compressor indicated at 20 provided with a fresh air intake line (not shown) and driven, for example, by an electric motor 2| or Diesel engine and discharging into a storage reservoir l9 and thence into a cooling device 22 for the compressed air. This device 22 may be designed to partially expand and thus cool the compressed air-only to approximately the temperature of the surroundin'g atmosphere-so that in its subsequent travel through the connecting pipes of the heating system, condensation of water vapor and/or frosting on the outside of these pipes will be obviated. This cooling may under some conditions be dispensed with and the warm compressed air be conducted through the pipe system. When needed, and in order to avoid excessive use of cold water,

' connecting pipe lines can occur on the pipes, nor

this cooling of the compressed air may conveniently be effected in well-known manner by utilizing either all or a fraction thereof for expending within, and thus driving, an expansion engine illustrated by the cooling device 22 which serves also to help drive, for the sake of economy, the shaft 23, 23, of the motor 2i and the compressor'20.

A control valve 24 is provided in the connection between the compressor and the cooling device so that the latter may be cut off, if desired; and a by-pass connection 25 with control valve 25' is provided in case it should be desirable to operate the heating system temporarily with the heated compressed air rather than starting up the boiler plant. This arrangement may be of advantage in the tropics, or late in the spring and early fall in temperate-climates, when moderate heating, for a few hours or so is needed, particularly of small buildings.

In the intended operation of the system for air-conditioning, however, the compressed air is delivered from its central source-as from the cooling device 22-by opening its discharge valve 26 to connect the same to the steam main I i at a point beyond the closed shut-off valve 21 included therein. This compressed air, which, if desired, may have been cooled approximately to the temperature of the surrounding atmosphere, is conveyed by the steam main II to the different radiating or heat-exchange units; but it is not conveyed directly thereto as in the ordinary operation of the system for heating purposes. It is first directed to an expansion'and mixer unit, hereinafter described; and a three-way valve 28 is provided in the radiator connection, the same being capable of closing the line to the radiator and of connecting the main solely with said expansion device. This device may be of any wellknown or special design and is indicated at 29, Figs. 1 to 3. A filter 30 may be interposed, if desired, to intercept dust, scale and any other foreign matter which might pass through the main. In the said expansion device 29 the air is expanded and thus chilled to the desired degree, and is then conveyed by a short connection 3| and delivery pipe 32 to a radiator, there being interposed the usual control or modulating valve 33 for controlling the inlet into said radiator.

The invention includes the provision of means for introducing into a radiator, with-this chilled air, of a relatively larger portion of the air which it is desired to cool and dehumidify. To this end, the expansion device 29 may be preferably of the mechanical type, and one in which the internal energy of the compressed air is used to drive an associated fan or blower device 35, coupled thereto and thereby caused to aspirate air from the surrounding room space or the external atmosphere through an inlet 36. The outlet of the blower is connected to the radiator l2, for example through the pipe 32, so that the chilled expanded air, together with the warm and humid air from the surrounding space, will be mixed while being delivered into the interior of the radiator l2, there being provided a threeway valve 38 in the radiator connection which is opened to the blower. In some instances it is desirable to interpose a filter for the room air aspirated into the blower, and such a filter 31 is indicated in the drawings as associated with blower 35. Moreover, for better appearance the entire expansion, blower and filter means may be encased in a suitably shaped housing 39, as ismore clearly indicated in connection with the and IS",

, 9,078,29l radiator l2; the front panel of this housing is shown removed from the unit associated with in Fig. i, and the side panel nearest the radiator is removed in Fig. 3.

Figs. 2 to 5 illustrate the details of a combined expansion, blower and filter unit diil'ering in some particulars from that shown in Fig. 1. In

this form, the fly-wheel l6, l6, and It".

comprises three sections,

and the piston is connected to this crank shaft by a connecting rod, wrist-pin and fly-wheels, i8

and are so weighted that when the compressed air beyond dead center, and after it has started its expansion stroke. At this point the inlet valve 34 will still be open and the outlet valve 3| will be closed. By this expedient the combined unit the piston will stop,

becomes self-starting upon re-admission of com-.

pressed air, since a force of several hundred pounds will be exerted upon the piston to start the expansion stroke thereof. The inlet valve 34.

is so actuated by its cam, as shown in Figs. 2 and 5, that the compressed air supply is cut 011 during the completion of the expansion stroke, whereby the internal energy of the compressed air is used to perform the work required to drive the unit.

The outlet valve 3| is so connected to the combined pulley and fly-wheel it through the link 3 l that both the pipe 3| from the expansion chamber and the delivery pipe 32 from the blower are closed during theexpansion stroke; except that, if desired, a moderate volume of hot room air may pass at this time through a small channel Sl' traversing the outlet valve 3| as indicated therein, in order to sweep the mist from the preceding cycle through the exit leg of the pipe 32 into the radiator. If desired, some or all.

of the room air aspirated by the blower,particularly during the expansion stroke when its outlet is closed,-can be allowed to escape through a suitable valve illustrated at 43 and which can be'so regulated by the user, by adjustment of the nut 44, that the proportion of warm room air which passes through the pipe 32 into the radiator at each cycle is such as to give the desired temperature and humidity in the air of the room. The blower 35 and the expansion device29, or both, may be either rotary or reciprocating in type. If both are rotary they can be directly connected on a common shaft. As illustrated in the drawings Fig. 1 hereof there is shown only the fly wheel I6 01' a reciprocating type of expansion engine 29, which may also serve as a pulley wheel and, together with the belt l1, drive a rotary blower as indicated. By adiabatically expanding the compressed air and using its internal energy in the engine 29 to perform useful work in drivingthe blower 35, the air issuing from the exhaust line 3| of the engine will be chilled to a temperature of minus 50 F. or even less. Consequently the connection pipes 3| and 32 may be made preferably of nonconducting material and as short as possible to avoid any undue condensation thereon; and the condensation resulting from the mixture oi the very cold, chilled expanded air with the portion of the warm, moist, ambient room air introduced into the radiator occurs entirely within the said radiator. The resulting water is removed from the radiator through the operation of the discharge valve ll.

The mixture of cooled air, which has been substantially freed from excess moisture, may

These sections are mounted pa ly. as shown, on the crank shatt I 6' which latter also serve as crank armsv is shut ofl, at a point then be discharged into the atmosphere s rounding the radiator through pipe II. It is pretel-red, however, to provide over the top of the radiator one or more perforated discharge pipes 1 ing system, should be of sufllciently large diameter to prevent undue back-pressure in the radiator and its inlet pipe 32; and said pipe l5 may branch out from the outlet pipe of a radiator between the radiator outlet and the thermostatic or other valve l4 customarily installed in the return line, as shown in the drawings. Where, as in most instances, this valve is of the "sylphon" or similar type'which is closed thermostaticallyi. e., when the temperature of low-pressure steam isattainedno change need be made in the valve or its connections, other than that just indicated. For, at the low temperatures employed inthis system of coo1ing, the outlet of said valve will remain open and allow all water of condensation in the radiator to flow through the valve and the return line to the basement and thus to the drainage system.

However, in order to prevent flow of cold, dry air, also, through the said return line, a water trap should be installed therein at a convenient point or points, indicated in the drawings at 4|. of the water inthis trap be sufllcient, as can easily be arranged, then water will flow therethrough at all times; but the stream of cold, dry air from the radiator will at all times be diverted into and through the exhaustpipe l5 between the valve' and the radiator.

The air-conditioning unit is placed in operative condition simply by manipulation of the threeway valves 28 and 38 so as to shunt the compressed air from the steam pipe into the air-conditioning unit. When the system is used for heating, with the three-way valves in the other position, then steam will flow in the usual manner directly into the heat-exchange unit, and entirely by-pass the air-conditioning unit.

A suitable valve 42 should be installed in the intake line to the expansion engine beyond the three-way valve 28, said valve being manipulated for the purpose of controlling the rate of flow of compressed air to the air-conditioning unit and, thereby, the temperature of the air issuing from the radiator into the room. This last-mentioned valve may be thermostatically controlled, if desired.

The extent of cooling and dehumidifying of the room air by the means disclosed herein may also be controlled by regulating, as by a throttle valve (not shown) on the inlet 36-, the ratio of the volumeof the air circulated by the blower to the volume of chilled air issuing from the expansion 4 temperature within the desired limits. Since temperature and humidity vary so much from time to time, it is not possible to give any definite instructions, more than to say that the tempera- 5 ture of themixture ofaspirated room air and chilled air within more or less, below the desired room temperature. Under proper conditions, the compressed air flowing from the storage reservoir and/or the i0 cooling device 22 will be free from oil vapor, or substantially so. However, when desirable, in order to prevent deposition of oil in the pipesof the heating system, a suitable oil filter (not shown) may beinstalled in the line, preferably. in the basement of the structure or closely associated with the hereinbefore described centrally located air compressor and cooling device 22. If desirable, the main of the steam-heating system and the return line may be physically disconnected from the boiler during those'seasons of the year when the heating system is to be used for cooling and general air-conditioning.

In place of the blower shown, an air injector (not shown) of any well-known type can be used to effect mixing of the humid warm room air with the chilled air from the expansion device 29. Under suitable conditions it is possible thus to aspirate and mix four to ten volumes of ambient warm air with one volume of chilled air issuing from the expansion device 29.

In general it may be said that the air should be compressed to 65 pounds gauge pressure or thereabouts in the centrally located air compressor 20, v

and may then be partially expanded in the cooling device 22 to about pounds gauge pressure, which, under most conditions, will cool the air at that pressure to, or approximately to, atmospheric temperatures. The air at the said pressure and temperature is then conducted into and through the steam main, risers and piping of the heating system, as hereinbefore described. Of course, it will be realized that under many conditions it is not necessary to cool the compressed air down to atmospheric temperatures, and that the same could be piped through the building without cooling, except such as results from the passage of the compressed air through the piping system of the building. i

With air at a pressure of 50 pounds at its inlet, the expansion device 29 should be so arranged that the air will expand therein to approximately zero pressure gauge, or to a few ounces positive pressure.--just sufllcient to force the expanded chilled air through the piping and radiators as' hereinbefore described. When an air injector is used in place of a blower, the pressure drop in the expansion device should be such that the chilled air from the outlet thereof has a pressure of from 5 to 10 pounds gauge, or any pressure sufficient to aspirate the desired volume of ambient room air by means of the jet .of chilled air, as before described; Of course, these pressures can be modified as circumstances demand, and are cited only by way of illustration.

When it is desired to use the compressed air for heating, temporarily, the cooling device 22 will be by-passed altogether by suitable manipulation of the valves 24, 26, and 25 provided therefor; and the three- way valves 28 and 38 will be turned to a position which will bypass the self-contained expansion unit associated with each radiator. In this way, the warm, compressed air from the compressor 20 will circulate through the radiator and into the room and then afford a moderate degree of heating. This may be used very eflecaorasos the radiator may be 15F;

tively in tropical or semi-tropical climates, particularly in small buildings, since it is there generally desirable to cool rooms 10 or so in the daytime and to heat them 10 or so during the evening, night and early morning hours.

The efliciencies attainable by the system herein disclosed are illustrated by the following results of practical tests of a unit built for refrige ation by the expansion of compressed air. In hese tests, with a 52 H. P. air compressor unit, the motive power required was derived in part from a prime mover and in part from the work done in a large expansion engine driven by the internal energy of the compressed air. A totalgof 52 H. P. from these two sources of energy was used to drive the air compressor which delivered air at 50 pounds per square inch, gauge. The volume of cold air delivered per hour was 15,000 cubic feet. The drop in temperature of the air in the expansion cylinders was 134 F., imparting a temperature below minus 50 F. to the said volume of air.

Calculation shows that one volume of air at 50 below zero, Fahrenheit, can be mixed with eight volumes of air at 90 F. and give nine volumes of air having a temperature of about 75 F. With air at -95, as in very warm summer weather, the air, as is well known, should be cooled to a temperature of from 75 to 80, under ordinary conditions. 0n the basis of the above, therefore, by the expenditure of 50 H. P. nine times 15,000 cubic feet or 135,000 cubic feet of air can be cooled per hour to 75 F. from a temperature of and can at the same time be dehumidifled'and filtered by the invention herein disclosed. That'volume of air equals the space of one hundred average size hotel, oillce or apartment rooms, 10 x 15 x 9 feet in dimension, each being 1350 cubic feet in capacity. In other words, on this basis, it will require by the present system, about V: H. P., or less than K. W. per hour to air-condition each room of the stated size when the outside temperature is 90 F.

I claim:

1..In a heating system including a plurality of variously disposed hollow heat exchange units and a central heating plant'normally connected therewith by a supply and return pipe line adapted to conduct steam or hot water from said plant to the said units and through the hollow channels thereof, the method of utilizing said system for air-conditioning by cooling and dehumidifying room air, which comprises compressing air at a central point, conducting it through said pipe line to the proximity of a heat exchange unit, there expanding the compressed air in such a way as to chill it, impelling the chilled air together with room air to be conditioned into the said hollow channels of said unit to cool and dehumidify the mixture, and discharging the conditioned air mixture from the said hollow channels of said unit into the air of the room to be conditioned.

2. In a heating system including a plurality of variously disposed hollow heat exchange units and a central heating plant normally connected therewith by a supply and return pipe line adapted to conduct steam or hot water from said plant to the said units and through the hollow chan- I nels thereof, the method of utilizing said system for air-conditioning by cooling and dehumidifying room air, which comprises compressing air at a central point, cooling the compresed air to approximately atmospheric temperature, conducting it through said pipe line to the proximity to be conditioned into the said hollow channels 01' said unit to cool and dehumidify the mixture,

and discharging the conditioned air mixture from the said hollow channels of said unit into the air of the room to be conditioned.

3. In a heating system includinga plurality of variously disposed hollow heat exchange units and a central heating plant normally connected therewith by a supply and return pipe line adapted to conduct steam or hot water from said plant to the said units and through the hOl-r low channels thereof, the method of utilizing said system for air-conditioning, by cooling and dehumidifying roomair, which comprises compressing air at a central point, conducting it through said pipe line to the proximity of a heat exchange unit, there expanding the compressed air in such a way as to chill it, impelling the chilled air together with room air to be conditioned into the said hollow channels of said unit to cool and dehumidify the mixture, draining the water of condensation from the unit through the said pipe line, and discharging the conditioned air mixture from the said hollow channels of said unit into the air of the room to be conditioned.

4. In a heating system including a plurality of variously disposed hollow heat exchange units and a central heating plant normally connected therewith by a supply and return pipe line adapted to conduct steam or hot water from said plant to the said units and through the hollow channels thereof, the method of utilizing said system for air-conditioning by cooling and dehumidifying room air, which comprises compressing air at a central point, conducting it through said pipe line to the proximity of a heat exchange unit, there expanding the compressed air in such a way as to chill it, impelling the chilled air together with room air to be conditioned into the said hollow channels of said unit to cool and dehumidity the mixture, and so discharging the conditioned air mixture from the said hollow channels of said unit as to bathe the exterior walls thereof with conditioned air.

5. In a heating system including a plurality of variously disposed hollow heat exchange units and a central heating plant normally connected therewith by a supply and return pipe line adapted to conduct steam or hot water from said plant to the said units and through the hollow channels thereof, the method of utilizing said system for air-conditioning by cooling and dehumidifying room air, whichcomprises compressing air at a central point, cooling the compressed air to approximately atmospheric temperature, conducting it through said pipe line to theproximity of a heat exchange unit, there expanding the compressed air in such a way as to chill it, impelling the chilled air together with room air' to be conditioned into the said hollow channels of said unit to cool and dehumidify the mixture,

draining the water of condensation from the unit through the said pipe line, and so discharging the conditioned air mixture from the said hollow channels of said unit as to bathe the exterior walls thereof with conditioned air.

6. The combination with a heating system which includes a plurality of variously disposed hollow heat-exchange units and a central heating plant normally connected therewith by a supply and return line adapted to conduct steam or hot water between said plant and said units and through the hollow channels thereof, oi means for utilizing said system for air-conditioning by cooling and dehumidifying room air,

which comprise means for-compressing air at a central point, means to conduct the compressed air through said pipe line to the proximity of a heat-exchange unit, an expansion element connected thereat to said pipe line and adapted to so expand the compressed air within the element as to chill it, means to impel the expanded chilled air together with room air to be conditioned into the hollow channels of said unit to t cool and dehumidify the mixture, and means to discharge the conditioned air mixture from the said hollow channels of said unit into the room to be conditioned.

7. The combination with a heating system which includes a plurality of variously disposed hollow heat-exchange units and a central heating plant normally connected therewith by a supply and return line adapted to conduct steam or hot water between said plant and said units and through the hollow channels thereof, of means for utilizing said system for air-conditioning by cooling and dehumiditying room air, which comprise means for compressing air at a central point, means to conduct the compressed air cooled to approximate atmospheric temperature through said pipe line to the proximity of a heat-exchange unit, an expansion element connected thereat to said pipe line and adapted to so expand the compressed air within the element as to chill it, means to impel the expanded chilled air together with room air to be conditioned into the hollow channels of said unit to cool and dehumidify the mixture, and means to discharge the conditioned air mixture from the said hollow channels of said unit into the room to be conditioned.

8. The combination with a heating system which includes a plurality of variously disposed hollow heat-exchange units and a central heating plant normally connected therewith by a supply and return line adapted to conduct steam or hot water between said plant and said units and through the hollow channels. thereof, or means for utilizing said system for air-conditioning by cooling and dehumidifying room air, which comprise means for compressing air at a central point,-means to conduct the compressed air through said pipe line to the proximity of a heat-exchange unit, an expansion element connected thereat to said pipe line and adapted to so expand the compressed air within the element as to chill it, means to impel the expanded chilled air together with room air to be conditioned into the hollow channels of said unit to cool and dehumidify the mixture, means to through said pipe line, and means to discharge the conditioned air mixture from the said hollow channels of said unit into the room to be conditioned.

9. The combination with a heating system which includes a plurality of variously disposed hollow heat-exchange units and a central heating plant normally connected therewith by a supply and return line adapted to conduct steam or hot water between said plant and said units and through the hollow channels thereof, of means for utilizing said system for air-conditioning by cooling and dehumidifyihg room air, which comprise means for compressing air at a central point, means to conduct the compressed air through said pipe line to the proximity of a heatdrain the water of condensation from the unit air together with room air to be conditioned into I the hollow channels of said unit to cool and dehumidify the mixture, and means to so discharge the conditioned air mixture from the said hollow channels oi. said unit as to bathe the exterior 10 walls of said unit with conditioned air.

10. The combination with a heating system .which includes a plurality of variously disposed hollow heat-exchange units and a central heating plant normally connected therewith by a supply and return line adapted to conduct steam or hot water between said plant and said units and through the hollow channels thereof, of means for utilizing said system for air-conditioning by cooling and dehumidifying room air,

which comprise means for compressing airat a central point, means to conduct the compressed air cooled to approximate atmospheric temperature through said pipe line to the proximity of a heat-exchange unit, an expansion element connected thereatto said pipe line and adapted to so expand the compressed air within the element as to chill it, means to impel the expanded chilled air together with room air to be conditioned into the hollow channels of said unit to cool and dehumidii'y the mixture, means to drain the water of condensation from the unit through said pipe line,and means to so discharge the conditioned air mixture from the said hollow channels of said unit as to bathe the exterior walls of said unit with conditioned air.

1 1. The combination with a heat radiator provided with hollow channels adapted to hold steam or hot water and connected to a supply and return pipe line, of air-conditioning means associated with said radiator, comprising an expansion element, means for supplying compressed air to the element for expansion therein to chill the expanded air, means for introducing the chilled air into the said hollow channels of the radiator together with room air to be conditioned, and means to discharge the conditioned air mixture from the radiator into said room.

12. The combination with a heat radiator provided with hollow channels adapted to hold steam or hot water and connected to a supply and return pipe line, of air-conditioning means associated with said radiator, comprising an expansion element, means for supplying compressed air through said pipe line to the element for expansion therein to chill the expanded air, means for introducing the chilled air into the said hollow channels of the radiator together with room air to be conditioned, and means to discharge the conditioned air mixture from the radiator into 60 said room.

13. The combination with a heat radiator provided with hollow channels adapted to hold steam or hot water and connected to a supply and re-' turn pipe line, of air-conditioning means associated with said radiator, comprising an expan- 65 sion element, means for supplying compressed air to the element for expansion therein to chill the expanded air, means for introducing the chilled air into the said hollow channels of the radiator together with room air to be conditioned, means to drain of! water of condensation through said pipe line and to discharge the conditioned air mixture from the radiator into said room.

14. The combination with a heat radiator provided with hollow channels adapted to hold steam or hot water and connected to a supply and return pipe line, of air-conditioning means associated with said radiator, comprising an expansion element, means for supplying compressed air to the element for expansion therein to chill the expanded air, means for introducing the chilled air into the said hollow channels of the radiator together with room air to be conditioned, and means to so discharge the conditioned air mixture from the radiator as to bathe the exterior walls of the radiator therewith.

15. The combination with a heat radiator provided with hollow channels adapted to hold steam or hot water and connected to a supply and return pipe line, of air-conditioning means associated with said radiator, comprising an expansion element, means for supplying compressed air through said pipe line to the element for expansion therein to chill the expanded air, means for introducing the chilled air into the said hollow channels of the radiator together with room air to be conditioned, means to drain oil water of condensation through said pipe line and, to so discharge the conditioned air mixture from the radiator as to bathe the exterior walls of the radiator therewith.

16. The combination with a heat radiator provided with channels adapted to hold steam or hot water, of means to cool, dehumidify, filter, circulate and ventilate room air, which include means to compress fresh air, means to expand the same to chill it, means employing the energy of expansion thereoi to aspirate room air through a filter and to impel the said roomand chilled air together through said channels to cool the mixture and to condense and deposit moisture therefrom, means to drain the water of condensation from the radiator, and means to discharge the conditioned air mixture into the room.

1'1. The combination with a heat radiator provided with channels adapted to hold steam or hot water, of means to cool, dehumidiiy and circulate room air, which include means to impel chilled air together with room air through the said channels to cool the mixture and to condense and deposit moisture therefrom, and means to discharge the conditioned air mixture'into the room.

18. The method of using a radiator provided with channels adapted to hold steam or hot water, to cool, dehumidiiy and circulate room air, which includes impelling chilled air together with room air through the said channels to cool the mixture and to condense and deposit'moisture therefrom, and discharging the conditioned air mixture into the room.

CHARLES J. THATCHER.

CERTIFICATE OF CORRECTION. 7 Petent No. 2,078,295. April 27, 1937.

CHARLES J. THATCHER.

ied that error appears in of the above numbered patent requiring correction .-as followe: Page'4, second column, after line 43, insert the following-'--paragre,phz;

It will also be understo those herein described ma scope of my invention.

od that ojher fixodi'fi' oei ions than y be made without departing from the "Henry Ven Arsd al'e; (Seal) Acting am-1550mm: Patents.

the printed" specifi oati'on

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