US3367132A - Valance type heat exchanger with trough means - Google Patents

Description

Filed Sepi. 2, 1965 Feb. 6, 1968 E. c. ELLIOTT 3,367,132

VALANCE TYPE HEAT EXCHANGER WITH TROUGH MEANS luvemon 5 ERNEs'rC. ELLIOTT .4 fimAm/mam Feb. 6, 1968 E. c. ELLIOTT 3,367,132

VALANCE TYPE HEAT EXCHANGER WITH TROUGH MEANS Filed Sept. 2, 1965 5 Sheets-Sheet 2 INvEN-roR l' ERNEST C. ELLIOTT 38 4 I s W7 ATTYS,

Fe. 6, 1968 c, ELLIOTT 3,367,132

VALANCE TYPE HEAT EXCHANGER WITH TROUGH MEANS Filed Sept. 2, 1965 5 Sheets-Sheet 5 [(Mit mum" 2O 5 gill INVE'NTOE ERNEST Cl. ELLlOTT A'r'rvs,

Unite States Patent Ofiice 3,367,132 Patented Feb. 6, 1968 3,367,132 VALANtIE TYPE HEAT EXCHANGER WITH TROUGH MEANS Ernest C. Elliott, Michigan City, IntL, assignor to Weil- McLain Company, Inc, Michigan City, Ind, a corporation of Indiana Filed Sept. 2, 1965, Ser. No. 484,690 3 Claims. (Cl. 62-285) A valance-type heating and cooling system is described having fin-and-tube units provided with means for slowing condensate runoff, for collecting and disposing of condensate, and for collecting and disposing of secondary condensation.

This invention relates generally to the heating and cooling of rooms, and more particularly to valance-type units which may be used selectively for heating, cooling, or for cooling with dehumidification.

The valance system is a comparatively new type of heating and cooling system which is beginning to find increasing use in homes, apartments, and otfice buildings. Like the baseboard system which it often replaces, the valance system utilizes recirculating fluid from .a central source, which fluid may either be heated or chilled, depending upon the effect desired. The fluid is passed through extended convector elements in each room or zone to be heated or cooled, and the natural convective flow of the heated or cooled air within the room is utilized to achieve the desired temperature conditions. The valance system differs from the baseboard system, however, in that the convcctor elements are placed substantially at or near the ceiling of the room or zone in which they are used. This placement enables the elements to be installed Without interference from doors, windows, or other obstructions which would necessitate interruptions and detours in a conventional baseboard system. Also, the construction of the valance elements may be lighter and more inexpensive, because they are not subjected to the bumps, knocks, and other abuse that they would have to absorb were they located close to the floor.

During heating, the elements of the valance system are warmed by heated fluid pumped from and returned to a central source. The convective action causes the heated air to be drawn up through the valance elements and spread across the ceiling of the room before it is drawn floorwards by the natural convective patterns of the room. The prolonged contact with and warming of the ceiling by the heated air enables a substantial amount of room warmth to be supplied by radiation from the ceiling.

In cooling with the valance system, chilled fluid is pumped from and returned to a central source, and the convective flow is in the opposite direction, being from the ceiling through the valance elements and thence downwards into the room. Dehumidification is achieved by causing the temperature of the valance elements during cooling to be below the dew point of the incoming air, thus causing moisture to condense on the elements from which it runs off and is collected for disposal. This is commonly done by means of troughs disposed below the elements into which the condensate is allowed to drip. The troughs are slightly inclined, causing the accumulated moisture to run to a drainage point from which it may be piped out of the room for disposal. A system of this type is disclosed by Bailey in his US. Patent No. 3,018,639, Heat Exchange for Structure with Trough Means, issued I an. 30, 1962.

A common difliculty with valance systems utilized for cooling and dehumidification is in the accumulation and disposal of condensed moisture. Conventional fin-andtube design, as shown in the Bailey patent, is influenced to a considerable degree by the requirement that the accumulated condensate be directed into a narrow trough as it runs off the fins. If not so directed, the condensate will drip and splash in an uncontrolled manner, often against the walls of the room, or onto the floor. A design which allows adequate control of condensate runoff, however, may be far from optimum for heat transfer purposes. Similarly, such a fin may be uneconomical of material because of the large amount of scrap involved in manufacture.

Another problem is that a secondary condensation, in which the cold condensate causes additional moisture to condense on the runoff trough, from which it may drip against the wall or into the room. Closely allied with this problem is the problem of condensation on the extended lengths of piping which run to or return from the various valance units in a given installation. This piping must be insulated to prevent moisture from condensing on it during cooling operations, and long lengths should be avoided in the interest of efliciency and economy.

Because valance units are installed near the ceilings of the rooms in which they are used, it is also necessary that they be light of weight and easy to install. They are always open to view, as opposed to baseboard units, and therefore must be of attractive and compact design. They should be as rigid as possible in a vertical direction, so as to require few hangers or supports, while retaining some flexibility in the horizontal direction to permit the accommodation of slight irregularity in walls or in the location of support brackets. The units should allow unimpeded convective air flow from both top and bottom to accommodate both heating and cooling modes of operation. The condensate trough must not be of overly large dimensions if obstruction of air flow through the unit is to be avoided. Furthermore, the slope of the condensate trough must be such that the condensate is carried from the valance units to a drain, from which the moisture may be piped out of the room and disposed of. Heretofore, in units such as that shown by Bailey, this has required that the entire valance unit be installed on an incline to insure the proper flow of runoff moisture.

A further problem in the design of valance units is in providing an adequate amount of dehumidification during cooling operation. In order to maintain comfortable conditions for room occupants without reducing the air temperature by an abnormal amount, it is necessary to provide an adequate rate of moisture removal when needed which will lower the relative humidity to a level consistent with comfort. In practice, it has been found that this level is about This type of performance requires the ability to remove a relatively high proportion of latent heat in condensation of moisture in relation to the amount of sensible heat removed in lowering the air temperature, with the ability to achieve ratios of at least 30% being desirable. If less moisture is removed, the tendency of the valance system will be to produce an undesirably cold, clammy environment.

Finally, it is desirable that heating and cooling units of the valance type be simple to install with no special tools or equipment, and it is also desirable that the tubes and fins of the valance system be resistant to bending during the handling required in the course of installation.

It is therefore an object of the present invention to provide an improved valance-type heating and cooling unit which is of compact, efiicient design and which is 0 relatively inexpensive to manufacture and to install. A

more specific object is to provide a fin-and-tube valance heating and cooling unit which has a favorable ratio of latentto sensible heat during cooling operation, while maintaining the desirable feature of controlled condensate runoff without the need for large troughs or other airflowobstructing devices. A related object is the achievement of high heat transfer rates from a valance unit with respect to the cost of materials involved in its construction.

Another object is to provide a condensate runoff trough which may be adjusted independently of its unit in the course of being oriented so as to drain condensate from the unit with which it is used, while eliminating runoif and splatter due to secondary condensation.

Still another object is the provision of a valance heat ing and cooling unit which is stiff in a vertical direction and relatively flexible in a horizontal direction, with elements of sufficient rigidity to resist bending and denting during handling and installation. A related object is the provision of valance heating and cooling units which are adaptable to multiple or side-by-side installation as well as the conventional wall mounting. A further related object is to provide a valance heating and cooling system which is adaptable for installation next to walls having high curtain valances or other obstructions, or from ceilings, without loss of heating or cooling efficiency.

These and other objects and advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings, in which:

FIGURE 1 is a perspective of the invention as incorporated in a conventional wall-mounted valance heating and cooling system;

FIG. 2 is a section taken through the plane A-A of FIG. 1;

FIG. 3 is a section similar to that of FIG. 2 except that it is shown in connection with a wall-mounted curtain valence;

FIG. 4 is a perspective of a mounting bracket as used in the system of FIG. 1;

FIG. 5 is a section of the suspension arrangement for the trough shown in FIG. 2, taken through the plane 5-5 of FIG. 2;

FIG. 6 is a section similar to that of FIG. 2; except that it is shown in connection with a multiple-unit wall-mounted installation;

FIG. 7 is a perspective of a fin as used in the system of FIG. 1;

FIG. 8 is a section taken through the plane 8-8 of FIG. 7;

FIG. 9 is a section similar to that of FIG. 8, except that several fins are shown as mounted on a tube;

FIG. 10 is a section similar to that of FIG. 4, except that the multiple unit is shown in connection with a ceiling-mounted installation;

FIG. 11 is a schematic view of the fluid flow paths which are present during the operation of the present invention; and

FIG. 12 is a perspective of the mounting bracket as used in the system of FIG. 6.

Turning now to the drawings; there is shown in FIG. 1 a valance heating and cooling unit constructed according to the invention. The unit is attached to the wall 10 near the ceiling by means of a plurality of horizontallyspaced brackets 12 which allow the fin-and-tube unit 14 to be easily mounted by merely sliding it horizontally into position within the brackets 12. The fin-and-tube unit 14 forms the heart of the heating and cooling element, and consists of tubes 16 and 17 and a plurality or perpendicular fins 18. The tubes 16 and 17 serve to carry heat transfer fluid through the fin-and-tube unit 14, distributing its heating or cooling effect to the air within the room by means of the heat transfer surfaces afforded by the fins 18.

For purposes of installation, each of the brackets 12 is provided with a pair of slots 20 which extend horizontally and end in a downward-extending notch 22 which is formed in a shape corresponding to that of the tubes 16 and 17. Each bracket 12 is of a thickness less than the spacing between individual fins 18 on the fin-and-tube unit 14 so that the fin-and-tube unit 14 may be mounted on the brackets 12 by merely sliding it horizontally into the slots 20 until the tubes 16 and 17 come to rest in the notches 22. Because the valance heat transfer unit of the invention is intended for use in cooling and dehumidifying of living spaces during the summer months, provision is made for the collection and disposal of moisture as it is condensed from the air during dehumidifying operation. For this purpose, a trough 24 is suspended beneath the fin-and-tube unit 14 at a gradual downward pitch so that moisture condensing on the fittand-tube unit 14 will be collected within the trough 24 and carried off to a point where it may be drained and disposed of. With a number of serially-connected units, the troughs 24 are connected to each other with a gradual downward slope that brings all the moisture collected to a common drain (not shown). In each unit, the trough 24 is suspended from each individual bracket 12 by means of wire hangers 26 which conform closely to the outline of the trough 24 so as to mount it securely, and terminate in hooked ends 28 which engage holes 29 supplied in the brackets 12 for this purpose. 7

It is a feature of the invention that the hangers 26 are of a material which is easily bent to shape withordinary hand tools, preferably wire. This enables the workman installing the unit to adjust the downward slope of the trough 24 to suit the particular conditions encountered in each installation. Because the length of each hanger 26 may be varied over a wide range of adjustment to provide the desired slope for the trough 24, the installation of the fin-and-tube units 14 and the bracket 12 in which they rest may be carried out without the need of providing the necessary slope for condensate runoff by accurate positioning of the units themselves, as has heretofore been the case. Stated another way, with the present invention the workman may install each heat transfer unit at the same optimum distance from the ceiling, and then, after the fin-and-tube units have been installed, may mount the trough 24 so that it slopes in any desired direction and with any desired degree of slope.

The appearance and operation of the unit are enhanced by the installation of the snap-on valance cover 32. This cover is constructed of a flexible, resilient material such as plastic or sheet metal and is formed with inwardlycurving surfaces or convolutions 34 and 35 which for purposes of installation are sprung apart and clipped into frictional engagement with corresponding notches 36 and 37 on the outer edge of each bracket 12. The resiliency of the cover 32 allows it to be simply snapped into place, for installation, and to be easily removed should the unit require servicing. It is an additional feature of the invention that the valance cover 32 is provided with a downwardlyextending portion 38 which reaches below and beneath the condensate trough 24 to catch and retain any secondary condensate which may form on and drip from the exterior surfaces of the trough 24 under conditions of abnormally humid inlet air, which might be encountered on initial start-up, or after the system had been out of operation for a prolonged period of time. For this purpose, a channel section 40 is provided in the downwardlyextending portion 38 of the valance cover 32. The amounts of moisture caught within the channel section 40 under these conditons are relatively small compared with that carried off by trough 24, and are simply retained until they again evaporate. The valance heat transfer unit will seldom be operated continuously, but will rather be run in cycles so that heat and moisture are removed only when necessary. Any moisture collecting within the channel section 40 during the cooling and dehumidifying cycle will begin to evaporate when the cooling ceases and will have disappeared by the time the next cooling cycle has begun. A significant feature of the invention is in the design the fins 18, in which several advantages are incorporated. One aspect of the design lies in the chevron-shaped embossed convolutions 42 which extend across each fin 18 from side to side. These convolutions serve to guide the moisture condensing on the fin 18 directly and positively into the trough 24, thereby eliminating the danger of condensate dripping from the unit into the room and allowing the trough to be made smaller and more compact. An important advantage of this construction is that the trough 24, which normally comprises a large impediment to the free flow of air pas-t the fins 18, may he made considerably narrower than the Widths of the fins 18 and the circulation of air through the unit thereby enhanced. The function of the horizontal convolutions 42 is to provide an obstacle over which a downwardflowing drop of condensate must pass. In the operation of a conventional flat fin, the cooling of air causes moisture to condense out in the form of tiny droplets. These droplets first appear as a fine fog over the shiny metal surface of the fin, and then, as the droplets combine with one another, larger and larger individual droplets are formed which eventually reach such a size that the pull of gravity overcomes their surface tension and draws them downward over the surface of the fin. In the normal fiat fin, the droplets pick up size and speed as they descend, until they are going at such a rate of speed that they are incapable of sharp changes of direction and are likely to fall straight from the fin. If the droplets are to be drawn from a single point on the fin, the lower edge of the fin must be gradually tapered in the manner described by Bailey in his US. Patent No. 3,()l8,639, previously mentioned, in order to provide some tendency for the droplets to accumulate at a low point on the fin for purposes of directing the runoff into the trough 24. In the present invention, the fin 18 may be made with a relatively shallow taper at the bottom, because the droplets as they run down do not acquire so great a speed that they are incapable of following the lower contours of the fin 18. When a droplet flowing down the surface of a fin 18 reaches one of the convolutions 42, its momentum in the downward direction is broken as it is forced to turn and follow the outline of the convolution. Because its downward momentum is now considerably lessened, it is able to follow the relatively shallow slope of the lower contour of fin 18 and is thereby accumulated at a center point 44 from which it drip into the trough 24. With larger fins, it has been found desirable to provide a second convolution 46 to provide additional slowing action of the droplets of water flowing from the upper portions of the fin 18. Because this second convolution 46 is also formed with the same slope as the lower portion of the fin 18, the moisture condensing on the upper portion of the fin 18 is also directed toward the center of the fin where it may fall vertically down to the center point 44. The convolutions 47 along the sides of the fin 18 and the convolutions 48 at the top are provided for purposes of stiffening the fin 18 and making it less likely to be bent or otherwise damaged during shipping or installation.

Yet another aspect of the invention lies in the configuration of the upper and lower portions of the fin 18. Fins of this type are generally produced by stamping them from sheet metal with the use of a punch press with a multiple die. Considerations of production economy require that the fins be of a shape so that a large number may be produced from sheet material with little or no scrap left over. In other words, it is desirable that the fins be of a nesting shape so that scrap losses may be reduced or eliminated. With fins having a sharply tapered lower edge for the purpose of guiding condensed moisture to a central point where it may drip into a trough, it is impractical to provide a corresponding shape at the upper end of the fin which would allow the fin to be stamped from sheet metal with a minimum scrap loss. Such an upper end shape would also be ineificient from a heat transfer standpoint because of the large amounts of metal which are relatively far removed from the coolant-carrying tubes, to which all the heat removed from the atmosphere must eventually be transferred. A similar condition, of course, exists when the unit is used for heating purposes. With the present invention, however, the fin 18 may be made in an economical chevron-shape, in which the slope of the lower edge of the fin is complementary and interrelated with the shape of the upper edge, so that in production the fin patterns may be laid out on the sheet stock end-to-end with a minimum of scrap loss. Excellent eat transfer capabilities are retained because the shallow angles permitted through the use of the condensate-catching convolutions 42 allow most of the metal surface near the upper and lower edges of the fin 18 to be relatively close to the tubes 16, 17 which are the source of the heating and cooling effect. For purposes of mounting, each fin 18 is supplied with holes 50 and 51, each having a flange 52 which serves to space the fins 18 from one another when stacked on the tubes 16, 17, and additionally provide intimate con-tact of each fin 18 with the tubes 16, 17 for maximum heat transfer effect.

An advantage of the present invention is that it is easily adaptable to various types of installations. As shown in FIG. 3, it may be installed above a curtain valance without any loss in the efficiency of heating or cooling. In this installation, screws 54 or other suitable fasteners are used to secure the brackets 12 to the curtain valance 56. To secure the most efiicient air flow in this installation, a backing strip 58 is afiixed between the brackets 12 and the valance 56. Besides insuring a smooth flow of air through the unit, this strip also provides a closure for the area above the curtain valance, thereby preventing the accumulation of dust or other debris.

Another aspect of the invention is the ease with which individual units may be combined into multiple installations. A wall-mounted installation using a pair of parallel fin-and-tube units is made possible by providing a wide bracket 60 containing a pair of deep slots 61, each slot having two notches 62 for the purpose of cradling the tubes 16 and 17 of the respective fin-and-tube units. As previously described, the individual fin-and-tube units are merely inserted horizontally into the slots 61 until the tubes 16, 17 rest in their respective notches 62. In this installation, the cover 32 with its condensate-catching channel sections 40 is again snapped into the notches 36 and 37 on the wide brackets 60. The trough 24 on its adjustable hangers 26 is installed as described previously.

For a multiple installation designed to be suspended from overhead, as from a ceiling or a rafter, a suspension bracket 64 is employed, containing horizontal slots 20 and tube notches 22 just as in the brackets 12 which are designed for wall mounting of a single unit. In the overhead-mounting version, two valance covers 32 are employed, one on each side. In this way each of the two fin-and-tube units 14 is hidden from view, and the respective channel sections 40 of each valance cover 32 extend beneath the troughs 24, thereby catching excess moisture and secondary condensation.

It is a feature of the invention that excess condensation and secondary condensation are prevented from falling into the room in which the valance unit is used. As has been mentioned, the channel sections 40 of the valance covers 32 serve to catch any overfiow from the troughs 24 and hold it until it has a chance to evaporate. The materials from which the units are made are also chosen with this consideration in mind. The various suspension brackets 12, 60, 64 are preferably made of metal or fiberglass for strength and ease of fabrication, and in keeping with the invention the metal brackets are coated with a heat-insulating material such a vinyl plastic to prevent the brackets 12, 6t), 64 from acting as heat transfer elements as do the fins 18. By decreasing the heat transfer rate through the use of heat-insulating material, condensation on the brackets 12, 60, 64 themselves is reduced or eliminated, and all condensation is confined to the fins 18 from which it may be controllably removed by the troughs 24 and drained ofl at some convenient point. Similarly, the valance cover 32 is also preferably made of a resilient, heat-insulating material such as flexible plastic, so that its external surfaces are prevented from reaching a temperature below the dew point of the room air, thereby avoiding condensation on the cover which might drip into the room. For the same reasons, the trough24 is also preferably constructed of a similar material. Other advantages obtained from the use of plastic heat-insulating materials include the lack of corrosion, ease of cleaning, and the ability to construct the units in a wide range of durable, colored finishes.

In practice, individual heat transfer units are located at various points throughout the home, oflice, or other space to be heated or cooled. A source. of heating or cooling of fluid 66 is located centrally and serves to supply the fluid to all of the individual units located throughout the installation. In order to prevent unevenness of heat transfer to the various individual units, a flow pattern is utilized which assures a substantially constant heat transfer rate from each individual unit throughout the system, with the additionaladvantage of eliminating the need for long lengths of insulated tubing which carry fluid to or from the more remote units. In carrying out this aspect of this invention, each bank of heat transfer units 68 is connected in series, so that fluid from the source 66 flows through one of the two tubes 16, 17 to the most remote unit of the bank 68, and returns through the other of the tubes 16, 17 until it again reaches the source 66. In this way, all fluid connections from the bank 68 are made at its end nearest the source 66, eliminating the need for long lengths of insulated piping extending to remote portions of the installation. Substantially the same heating or cooling effect is obtained from each unit of the bank 68 because the effect of fluid flowing both to and from the source within a single unit causes the average temperature of the unit to reach a uniform value which is substantially the same for every unit of the bank 68. Where fresh heating fluid at higher temperature enters a unit close to the source 66, its higher temperature is balanced by the returning flow of fluid which has had its temperature reduced by having passed through the entire bank 68 of heat transfer units. The next unit in the series receives fluid which has had its temperature reduced slightly by passing through the first unit, and is balanced by fluid which has not been quite so exhausted of its heat transfer potential because it has not yet passed through the last unit in its path. In this way, the temperatures of the entering and returning fluid in each unit of the bank 68 tend to average, giving each unit a substantially uniform heat transfer capability.

It will be noticed that in this levelling process, the units near the source will in some degree tend to transfer heat from one flow of fluid to the other as Well as to the air that is in the room. While some heat transfer effect may thereby be lost, it does not tend to decrease the thermal efficiency of the system. When the unit is being used for heating, for example, heat transfer from the warm incoming fluid to the cooler returning fluid tends to raise the temperature of the returning fluid and reduces the amount of heat necessary to bring the returning fluid up to the temperature at which it will be recirculated through the system. When the system is used for cooling, the same effect is observed, with the heat loss between the entering and returning fluid tending to reduce the range through which the returning fluid must be cooled before being returned to the system. To accommodate this eifect, only a slight increase in the pumping capacity of the system is required.

I claim as my invention:

1. In a valance cooling and dehumidifying unit, the combination of a fin-and-tube assembly, the surface of each fin having a raised portion extending fully across the fin from side to side for impeding the. downward flow of condensate on the fin surface, vertical mounting plates for said assembly, said mounting plates carrying said fin-and-tube assembly in supporting relationship, an elongated condensate trough, and a plurality of hangers suspending said trough from said mounting plates, each of said hangers being bendable to varying lengths for adjustably suspending said troughs from said mounting plates at a gradual downward pitch relative to said assembly and having a lower portion substantially conforming to the underside profile of the condensate trough and enclosing said profile, said lower portions having verticalupward extensions on each side, said extensions terminating in hooks for removable engaging said vertical mounting plates.

2. In a valance cooling and dehumidifying system, the combination of a fin-and-tube assembly having a tube carrying a multiplicity of perpendicularly disposed metal fins, a condensate trough disposed beneath said fins for collecting moisture condensed on the said fins, and a plurality of mounting plates carrying said fin-and-tube assembly and said trough, said mounting plates being adapted to be fixed in vertical support position and having a surface of heat-insulating material,.said mounting plates each having an upper and a lower edge, each edge having a notch, and a valance cover mounted substantially in front of said fin-and-tube assembly, said cover having a depending portion of trough-like cross section disposed substantially beneath and spaced from said condensate trough, said cover being of resilient material and having an upper and a lower extended horizontal convolution, said convolutions being capable of resilient frictional engagement with said notches.

3. In a cooling and dehumidifying system, the combination of a fin-and'tube heat exchanger assembly having a tube carrying a multiplicity of perpendicularly disposed metal fins, a condensate trough disposed beneath said fins for collecting moisture condensed on the said fins, a plurality of mounting plates carrying said fin-andtube assembly, means carrying said condensate trough below said fin-and-tube assembly, each of said fins having a substantially chevron-shaped convolution extending continuously across the fin from side to side, the lowermost point of said convolution being disposed vertically above said condensate trough whereby condensate flow during dehumidifying operation is controllably directed into said trough.

References Cited UNITED STATES PATENTS 1,557,467 10/ 1925 Modine.

2,089,367 8/1937 Harbers 62-290 2,133,354 10/ 1938 Krackowizer 62-290 2,210,725 8/1940 MacMaster 62290 X 2,667,041 1/ 1954 Henderson 62-290 2,722,403 11/1955 Guerra et a1 165-181 X 2,872,162 2/1959 Marini 165-55 2,876,631 3/1959 Bailey 62-285 2,896,426 7/1959 Ayliug 62-285 3,018,639 1/1962 Bailey 165-55 X 3,074,477 1/1963 Whalen 165-50 X 3,244,223 4/1966 Edwards 165-50 X FOREIGN PATENTS 849,373 8/1939 France.

EDWARD. J. MICHAEL, Primary Examiner.

ROBERT A. OLEARY, Examliner.

M. A. ANTONAKAS, Assistant Examiner.

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