US3786649A

US3786649A - Water chiller and storage system

Info

Publication number: US3786649A
Application number: US00277271A
Authority: US
Inventors: R Kirschner
Original assignee: PATTERSON KELLEY CO
Current assignee: HARSCH Corp (HARSCO)
Priority date: 1970-11-27
Filing date: 1972-08-02
Publication date: 1974-01-22
Anticipated expiration: 1991-01-22

Abstract

A dual mode operative water chilling and storage system for supplying ''''chilled'''' or cooled water or the like under both normal and peak demand conditions. The system includes a chilled water storage tank having a water supply inlet for replenishing water withdrawn from the tank, a conduit system including means for forcibly circulating water from a higher region to a lower region of the tank and including means for cooling the circulating water; means connected into the system for withdrawing chilled water up to a given rate of flow which is in excess of the rate at which water is normally circulated through the conduit system; and normally closed means for connecting the lower region of the tank in flow communication with the withdrawal means whenever the withdrawal rate exceeds the normal circulation rate to supplement the normal delivery rate of the system.

Description

United States Patent [191 Kirschner Jan. 22, 1974 WATER CHILLER AND STORAGE SYSTEM [75] Inventor: Robert F. Kirschner, Lakeville,

Mass.

22 Filed: Aug. 2, 1972 21 App]. No.: 277,271

Related U.S. Application Data [63] Continuation-in-part of Ser. No. 93,342, Nov. 27,

1970, Pat. No. 3,688,833.

[52] U.S. Cl 62/201, 62/394, 165/108 Primary ExaminerMeyer Perlin Attorney, Agent, or Firm-Granville M. Brumbaugh et al.

[57] ABSTRACT A dual mode operative water chilling and storage system for supplying chilled or cooled water or the like under both normal and peak demand conditions. The system includes a chilled water storage tank having a water supply inlet for replenishing water withdrawn from the tank, a conduit system including means for forcibly circulating water from a higher region to a lower region of the tank and including means forcooling the circulating water; means connected into the [51] Int. Cl. F25d 17/02 System for h a ng c lled ater up to a given [5 eld Of Search 62/98, 20l, 389, 394, 399; rate of flow which is in excess of the rate at which 165/103 water is normally circulated through the conduit system; and normally closed means for connecting the [56] Refer n Cit d lower region of the tank in flow communication with UNITED STATES PATENTS the withdrawal means whenever the withdrawal rate exceeds the normal circulation rate to supplement the 51212633 22323 Sill-5121?:33::1...................::::: 23/3321 normal delivery rate of the System V 26 Claims, 3 Drawing Figures i t t. '1

EZESC 46"-omncs 3O POINT REFRIGERANT OUTLET 2O REFRIGERANT INLET HEAT EXOHANGER luuu 44 co| 0 WATER FLOW CONTROL VALVE COLD WATER nsvsnsme SPARGER PATENTED SHEET 1 BF 2 mOEEO .PM CDO mmhdcs ow :10

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5350 ON E3595? WATER CHILLER AND STORAGE SYSTEM CROSS REFERENCE TO RELATED APPLICATION This application is a continuation-in-part of copending application Ser. No. 93,342 of Robert F. Kirscher, for Improved Water Heating and Storage System, filed Nov. 27, 1970, now US. Pat. No. 3,688,833.

FIELD OF THE INVENTION The present invention relates to a water chilling, or cooling, and storage system which is particularly adapted, by way of example, to meet the cooling loads and cold water use requirements of multiple dwellings, office buildings, commercial and industrial installations and facilities, and the like, and overcomes certain deficiencies of previous systems.

SUMMARY OF THE INVENTION The invention features, in one embodiment, provision of a water cooling and storage tank having a relatively warm water supply inlet for replenishing water withdrawn from the tank and a shrouded heat exchanger which receives water to be chilled, or cooled, at its inner end portion from a novel selective flow source/rate feed conduit system. The shroud is connected into a chilled water delivery conduit at its outer end portion. The conduit system includes a first conduit leading from an upper intake structure, e.g., a manifold, for drawing in relatively warm water from the upper region of the tank and a second conduit leading from a lower combination intake/output structure, e.g., another manifold, for taking in chilled water from the lower region. In one preferred form of conduit system arrangement, the lower manifold extends outwardly of the tank for flow communication with the outlet end portion of the shrouded cooling unit and includes a continuously running pump normally inducing a constant circulation of water from the upper region of the tank, through the cooler, and back into the lower region of the tank. i

' The first conduit is designed so as to permit only a normal" rate of flow (equivalent tothe rate of circulation through the pump plus withdrawals from the system at normal" rates) of water from the upper region of the tank into the heat exchanger. This normal" rate preferably corresponds to the designed heat exchange recovery rate of the system. A pre-selected flow rate restrictive orifice installed in the line of the first conduit provides a practical and convenient method for establishing this first conduit flow rate parameter. The second conduit includes an inline valve device, which is operable to selectively connect the lower manifold in flow communication with the heat exchanger only when the withdrawal demand rate on the delivery conduit exceeds the permitted rate of flow of water through the flow limiting orifice of the first conduit, as explained hereinabove.

Thus, during normal" circulation operation and/or during normal" withdrawals of chilled water from the system, water input to the heat exchanger is drawn solely from the upper region of thetank, i.e., through the upper manifold; any chilled water withdrawn from the system being replaced by warmer supply water entering into the upper region of the tank. However, when chilled water withdrawal demands are in excess of the flow rate determined by the flow limiting orifice,

the valve in the second conduit automatically opens to permit previously cooled water to be withdrawn from the lower region of the tank, i.e., through the lower manifold, and into the delivery conduit system, at a rate sufficient to satisfy the excess demand.

The system is therefore automatically balanced with respect to storage water cooling and chilled water delivery requirements, and insures delivery of water at a prescribed temperature, while at the same time maintaining highly desirable temperature stratification conditions interiorly of the tank. By positively promoting stratification conditions within the tank, a smaller'tank than conventionally required may be used for any given application.

The present system also provides for a more even and precise control of temperature, and therefore permits a more even draw upon the refrigerant source.

BRIEF DESCRIPTION OF THE DRAWINGS The nature and mode of operation of the invention will now be more fully described in the following detailed description taken with the accompanying drawings wherein:

FIG. I is a schematic illustration, partly in section and with parts broken away for clarity, of one form of the water chilling and storage system of the invention;

FIG. 2 is a schematic illustration of another embodiment of the invention, also partly in section and with certain parts broken away; and

FIG. 3 is a detail view depicting an alternative construction of the warm water inlet to the tank which may be employed in either of the systems shown in FIGS. 1 and 2.

DESCRIPTION OF EXEMPLARY EMBODIMENTS As illustrated in FIG. 1, the invention may be embodied in a chilled water delivery system including a storage tank 10 having a warm water inlet connection 12 for replenishing chilled water withdrawn from the tank. A cooling unit or heat exchanger, designated generally at 14, includes a tubular shaped shroud 16 housing a bundle of return bent heat-exhcange tubes 18, which extend from a tube sheet and refrigerant fluid supply assembly 20 closing the outer end of the shroud 16. Alternately disposed baffle plates 21 are preferably arranged within shroud I6 to guide the flow of water therethrough along an undulating or zig-zag path relative to tubes 18 to insure maximum cooling efficiency. A chilled water delivery conduit 22 is arranged in communication with the interior of the shroud 16 adjacent its delivery end portion, which as shown in the drawing preferably is arranged exteriorly of tank 10. The heat exchanger 14 may, if desired, be located entirely outside of or inside of the tank.

In the embodiment of FIG. 1, the inlet end portion of shroud 16 is disposed interiorly of tank 10 and is connected in open communication, by means of a conduitfitting 24, with first and

second feed conduits

26 and 28, respectively. The first or higher conduit 26 communicates with the interior of tank 10, by way of example, through an upper intake manifold 30, which extends generally horizontally in the upper region of the tank. Mnaifold 30 may conveniently be constructed as a tubular conduit perforated at intervals therealong, as indicated at 32, to permit the withdrawal of water from the upper region of the tank in gentle and evenly distributed manner. This construction avoids excessive turbulences and agitations of the stratified warmer water within the upper levels of the tank, such as normally occur during draw periods. Also, a deflector 34 may be provided to guide the warm water entering the tank through inlet connection 12 so that it travels upwardly and across the upper level of the tank, thereby further avoiding a breakdown of the natural temperature Stratification mechanism operating within the tank.

A conduit 36 is provided to extend from the chilled water withdrawal conduit 22 to the intake of a preferably continuously running pump 40 and from the discharge of the pump into a lower manifold or sparger" 42, which extends generally horizontally throughout a substantial portion of the lower region of the tank. The manifold 42 is preforated at intervals therealong, as indicated at 43, in order to permit the gentle and even introduction of chilled water into, or withdrawal of chilled water from, the lower region of tank 10, and is arranged to be normally excommunicated from but on occasion in flow communication with the second conduit 28 through a normally closed valv'e device 44, which is selectively operable between closed and variably open positions.

Thus, the pump 40 normally operates to draw water from across substantially the entire region of tank 10, through the manifold 30, first conduit 26, heat exchanger 14, conduit 36, and to then discharge it through lower manifold 42 across substantially the entire lower region of the tank. By nature, the less dense warmer water floats on top of the relatively cold water in the lower level of tank in the absence of external turbulent influences.

Preferably, the valve 44 is of the pressure-differential responsive type and is adjusted so as to remain closed when operating under pressure differentials such as are encountered under normal operations of the system, i.e., such as are induced by operation of the circulating pump 40 and normal" withdrawals of chilled water within the range of the chill recovery rate design of the system. Thus, under idling (no withdrawal and/or normal" withdrawal) conditions, pump 40 operates to gently circulate water from the upper region of the tank 10, through the heat exchanger 14, and then into the lower region of the tank, thereby maintaining and/or gradually bringing the entire tank contents at or to the desired temperature, without disturbing in the meantime the natural temperature stratification phenomenon within the tank.

Should withdrawal demand for chilled water on the conduit 22 increase substantially above the pump circulation rate, however, the chilled water flow control valve 44 will open so as to allow appropriate amounts of chilled water to be drawn from the lower region of the tank through the manifold 42. This additional water will mix with water being drawn in through the upper manifold 30 and will then flow through the cooling unit 14 to delivery conduit 22. Thus, the withdrawal of chilled water from the lower tank region to meet the excess" demand imposes no appreciable additional load on the refrigerant supply system, yet insures that water delivered by conduit 22 to the point of intended use under such conditions will be at the prescribed temperature.

As explained hereinabove, it is a particular feature of the present invention that the conduit 26 is restrictd to convey water at only a prescribed rate, such as by provision of the orifice device illustrated at 46. Orifice device 46 may be of any suitable design, and for example may simply comprise an apertured disc engaged between opposite face plates (see FIG. 2 for example) which are threaded onto adjacent sections of the conduit 26. It may also take the form ofa venturi (see HO. 1). In any event, the flow aperture of the device 46 is sized as to permit a rate of flow that may be less than but preferably is not substantially greater than the heat exchange recovery rate of the system before developing a pressure drop across the orifice (at the pump circulation rate) such as will operate to cause the valve 44 to open. Advantageously, this predetermined maximum flow rate capacity of the orifice device 46 is selected to be substantially equal to the heat exchange recovery rate of the system. While the rate of flow of relatively warm water from the upper region of tank 10 may be limited by merely reducing the diameter of either or both of the manifold 30 (or of the openings 32) and the first conduit 26, the utilization of a device 46 is preferred, since it facilitates initial design and installation and permits the system to be readily adjusted to meet the specific requirements of any given installation.

Hence, it will be appreciated that during idling and- /or normal" withdrawal conditions, the orifice device 46 is operative to permit the requisite rate of flow from the upper region of tank 10, and the valve 44, being normally closed, is operative to prevent any undesirable short-circulating of chilled water flow from within the lower manifold 42 through conduit 28 and back through the cooling unit. However, whenever withdrawals of chilled water in excess of the recovery rate of the system are being made, the orifice device 46 induces a differential pressure condition to exist between the portions of conduits 26-28 lying between the orifice device 46 and the valve 44 on the one hand and the interior of tank 10 on the other, thereby causing valve 44 to open and permit delivery to the heat exchanger and thence to the outlet conduit 22 of an additional supply of previously chilled water from the lower region of the tank.

Particularly in cases where pump 40 is not of the positive displacement variety, it is preferable to provide a flow check valve 52 in the line of the pump discharge to prevent any back-flow of water from the lower region of the tank, through the pump and into the water delivery conduit when more than normal chilled water withdrawals are being made. This insures that all water entering the withdrawal system will be at the prescribed temperature.

A temperature sensor 55, which preferably is positioned adjacent the outlet end portion of the cooling shroud 16, will at all times accurately note the temperature of water passing from the heat exchanger 14 and will serve to properly control the refrigerant supply thereto, as is well known in the art. Should the entire contents of the tank 10 attain the prescribed temperature, the sensor will deenergize the cooling unit until such time as the temperature of the circulating water rises above the desired withdrawal temperature.

The valve 44 may be of any acceptable design. For example, it may be of the spring-loaded pressurebalance type, operating strictly in response to pressure differentials when the system is out of fluid flow balance," due to any excessive chilled water withdrawal be provided in the'form of a vertically standing tank.

This is illustrated in FIG. 2 in connection with a modified embodiment of the chilling and storage system of 1 the invention, wherein similar components are designated by similar prime" numerals.

In the FIG. 2 embodiment, the upper manifold 32', the lower manifold 42 and the fitting 24" are shown as being extended through one sidewall of the tank l0, so as to position the first and second conduits 26' and 28 exteriorly of the tank in order to facilitate adjustment and/or maintenance of the flow control valve 44' and the orifice device 46.

Further, FIG. 2 illustrates an arrangement whereby thewcooling tubes 18' may be withdrawn from the shroud 16' without loss of water from tank and without interruption of the capability of withdrawing chilled water through delivery conduit 22' from the lower region of the tank. To this end, a by-pass conduit 95 having a normally closed valve 96 is arranged to directly connect conduit 22" into the bottom of tank 10, and normally

open valves

99 and 100 are provided in conduit 22 adjacent the outlet end portion of the shroud 16 and in the conduit-fitting 24', respectively. Thus, when the

valves

99 and 100 are closed and the valve 96 is open, the interior of shroud 16' is functionally isolated from the rest of the cooling system and conduit 22' is connected in direct flow commuication with tank 10'. Further, it is preferable to provide normally open valves'97 and 98 in line 36' at positions upstream and downstream of the pump 40" in orderto permit maintenace on or replacement of pump 40'.

In this embodiment, the warm water inlet 12' may conveniently connect into the top of the tank 10'. A deflector plate 34' may be provided in association therewith to reduce turbulence and preserve thermal stratification. l a

FIG. 3 illustrates another alternative construction of the warm water inlet connection to the tank 10", wherein the cold water supply inlet 12 is connected directly into upper manifold 30". This arrangement may in'some cases be desirable from the standpoint that it both simplifies the tank construction and prevents undesirable turbulent water flow patterns within the tank upon admission of warm supply water during a chilled water draw period. It may be employed in either embodiment illustrated.

Any suitable refrigerant and supply system therefor may be used. For example, the heat exchanger 14 might be connected to a central refrigerant supply system and the refrigerant, e.g., a brine solution or the like; circulated from the system through the heat exchanger tubes. Alternatively,a self-contained circulation system could be employed as part of the overall chilling and storage system. If desired, chilled water alone could be used as the refrigerant. The direct expansion or vaporization of a refrigerant such as Freon may also be incorporated in the heat exchanger, being fed directly from the exapansion valve and compressor.

It will be understood by those skilled in the art that the above-described embodiments are intended to be merely exemplary, in that they are susceptible of modification and variation without departing from the spirit and scope of the invention. For instance, although the upper and lower water intakes have been described and illustrated herein as manifolds, other forms of intakes may also be used. Thus instead of connecting to the

manifolds

30 and 42, the

conduits

26 and 28 may simply open directly to the tank interior. Also, the flowcontrol valve 44 and the flow-limiting orifice device 46 may be located at the ends of the

conduits

28 and 26, respectively, where they would be in direct flow communication with the respective tank water regions. All such modifications and variations, therefore, are encompassed by the invention as defined in the appended claims.

We claim: 1. A water chilling and storage system comprising in combination:

a chilled water storage tank; means, including means for chilling water passing therethrough, for normally circulating water from an upper region of the tank to a lower region of the tank, thereby tending to establish a reservoir of relatively cold water at least in the lower region of the tank; first intake means disposed within the upper region of the tank and connected to the circulation means upstream of the chilling means for permitting inflow of water to the circulation means from the upper region at up to a predetermined flow rate;

second intake means disposed within the lower region of the tank and connected to the circulation means upstream of the chilling means;

outlet means connected to the circulation means downstream of the chilling means for delivering chilled water to a point of use at up to a flow rate greater than the predetermined flow rate capacity of the first intake means;

inlet means for supplying relatively warm water to the upper region of the tank to replenish water "withdrawn from the tank through the outlet means;

and

normally closed valve means associated with the second intake means for admitting water to the circulation means from the lower region of the tank when the flow rate demand on the outlet means exceeds the predetermined flow rate capacity of the first intake means.

2. A water chilling and storage system according to claim 1 wherein the predetermined flow rate capacity of the first intake means is substantially equal to or less than the rate at which water is normally circulated by said circulation means.

3. A water chilling and storage system according to claim 1 wherein the predetermined flow rate capacity of the first intake means is substantially equal to or less than the heat exchange recovery rate of the chilling means.

4. A water chilling and storage system according to claim 1 wherein the predetermined flow rate capacity of the first intake means is substantially equal to the heat exchange recovery rate of the chilling means.

5. A water chilling and storage system according to claim 1 wherein the valve means comprises a pressureresponsive valve that opens in response to the pressure differential created thereacross when the flow rate demand on the outlet means exceeds the predetermined flow rate capacity of the first intake means.

6. A water chilling and storage system according to claim 1 wherein the circulation means includes a conduit extending into the lower region of the tank for delivering chilled water thereto, and the second intake means is in part comprised by said conduit.

7. A water chilling and storage system according to claim 1 wherein the first intake means includes flow restricting orifice means for limiting the maximum rate of flow of water passing to the circulation means from the upper region of the tank to said predetermined flow rate.

8. A water chilling and storage system according to claim 1 wherein the first intake means is directly connected to the warm water inlet means.

9. A water chilling and storage system according to claim 1 wherein:

the first intake means includes a first manifold extending generally. horizontally within the upper region of the tank; and

the second intake means includes a second manifold extending generally horizontally within the lower region of the tank.

10. A water chilling and storage system according to claim 9 wherein the second manifold is connected in normally open flow communication to the circulation means downstream of the chilling means, whereby chilled water may be delivered to the lower region of the tank through the second manifold when the valve means is closed.

ll. A water chilling and storage system according to claim 10 wherein:

the first intake means further comprises flow restricting orifice means interposed between the first manifold and the circulation means for limiting the rate of inflow of water through the first manifold; and

the valve means comprises a pressure-responsive valve interposed between the second manifold and the circulation means.

12. A water chilling and storage system according to claim 11 wherein the flow rate capacity of the first intake means is limited by the flow restricting orifice means to substantially equal to or less than the heat exchange recovery rate of the chilling means.

13. A water chilling and storage system comprising in combination;

a tank having warm water supply inlet means for replenishing water withdrawn from the tank;

a shroud having an inlet end portion extending inwardly of the tank and having an outlet end portion arranged exteriorly of the tank;

immersion chilling means arranged within the shroud for chilling water passing therethrough;

chilled water withdrawal means connected into the outlet end portion of the shroud for allowing the withdrawal of chilled water from the tank at up to a given rate of flow;

first water intake means disposed within an upper region of the tank and connected in flow communication with the inlet end portion of the shroud for permitting inflow of water to the shroud at up to a rate less than said given rate of flow, thereby to insure that water passing from the upper region is chillcd to a desired withdrawal temperature by the chilling means;

chilled water conduit means connecting the outlet end portion of the shroud in flow communication with a lower region of the tank and including pump means for normally circulating water between the tank regions successively through the shroud and the chilled water conduit means, thereby tending to establish a reservoir of water at or near said desired withdrawal temperature in at least the lower region of the tank;

second water intake means disposed within the lower region of the tank and connected in flow communication with the inlet end portion of the shroud; and

normally closed valve means associated with the second water intake means for admitting water therethrough to the shroud inlet end portion from the lower region whenever the flow demand rate on the chilled water withdrawal means is greater than the flow rate capacity of the first water intake means.

14. A water chilling and storage system according to claim 13, wherein the warm water supply inlet means is connected into the first water intake means.

15. A water chilling and storage system according to claim 13 wherein the chilled water conduit means includes a conduit extending into the lower region of the tank for delivering chilled water thereto, and the second water intake means is in part comprised by said conduit.

16. A water chilling and storage system according to claim 13 wherein the maximum flow rate capacity of the first water intake means is substantially equal to or less than the heat recovery rate of the chilling means.

17. A water chilling and storage system according to claim 13 wherein the first water intake means includes separate flow restriction means for limiting the rate of fiow of water therethrough.

18. A water chilling and storage system according to claim 13 wherein:

the first water intake means includes an apertured upper manifold extending generally horizontally within the upper region of the tank and a first conduit connecting the upper manifold to the inlet end portion of the shroud;

the chilled water conduit means includes an apertured lower manifold extending generally horizontally within the lower region of the tank;

the second intake means includes a second conduit connecting the lower manifold to the inlet end portion of the shroud; and

the valve means is arranged in the second circuit,

whereby the valve means admits water from the lower region through the lower manifold and the first conduit to the shroud inlet end portion whenever the withdrawal demand on the chilled water withdrawal means is greater than the maximum flow rate capacity of the first intake means.

19. A water chilling and storage system according to claim 18 wherein the first and second conduits are located within the tank.

20. A water chilling and storage system according to claim 18 wherein the first water intake means includes flow restriction means arranged in the first conduit.

21. A water chilling and storage system according to claim 13 further comprising:

by-pass conduit means, including second normally closed valve means arranged exteriorly of the tank,

- connecting the chilled water withdrawal means to the lower region of the tank;

normally open valve means arranged exteriorly of the tank for controlling flow of water from the outlet end portion of the shroud to the chilled water withdrawal means; and

normally open valve means arranged exteriorly of the tank for controlling flow of water from the first water intake means to the inlet end portion of the shroud, whereby when the normally open valve means are closed and the second normally closed valve means is opened, the immersion cooling means may be withdrawn from the shroud without loss of water from the tank and chilled water may be withdrawn through the chilled water withdrawal means directly from the lower region of the tank.

22. A water chilling and storage system according to claim 21 wherein normally open valve means are arranged exteriorly of the tank in the chilled water conduit means upstream and downstream of the pump means, such that when the last said valve means are closed the pump means may be removed without loss of water from the tank.

23. A water chilling and storage system according to claim 13 wherein the valve means comprises a pressure-responsive valve that opens in response to the pressure differential created thereacross when the flow rate demand on the chilled water withdrawal means exceeds the maximum flow rate capacity of the first water intake means. I

24. A water chilling and storage system according to claim 13 further comprising means responsive to the temperature of the chilled water in the outlet end portion of the shroud for controlling operation of the chilling means.

25. A water chilling and storage system comprising in combination:

a chilled water storage tank including a relatively warm water supply inlet for replenishing water withdrawn from the tank;

outlet means for withdrawing chilled water from said tank at up to a given rate of flow;

a conduit system for normally circulating water from an upper to a lower region in the tank, the conduit system having chilling means for chilling water being circulated therethrough, thereby tending to bring the contentsof the tank at least at the lower region down to a predetermined withdrawal temperature, the outlet means being connected in flow communication with the conduit system downstream of the chilling means; and

first and second tank water intake means in the conduit system upstream of the chilling means, the first intake means being disposed in the upper region for supplying water to the chilling means at up to an amount below said given rate of flow and the second intake means being disposed in the lower region for supplying a flow of water from the lower region to the chilling means, whenever the flow rate demand on the chilled water outlet means exceeds said amount, at a rate accommodating for the difference between said demand rate and said amount.

26. A water chilling and storage system according to claim 25 wherein the first intake means produces a predetermined pressure differential in the conduit system relative to the tank upstream of the chilling means whenever the first intake means tends to take in water exceeding said amount due to the chilled water withdrawal demand on the outlet means exceeding said amount, and

the second intake means includes normally closed valve means operable by said pressure differential.

Claims

1. A water chilling and storage system comprising in combination: a chilled water storage tank; means, including means for chilling water passing therethrough, for normally circulating water from an upper region of the tank to a lower region of the tank, thereby tending to establish a reservoir of relatively cold water at least in the lower region of the tank; first intake means disposed within the upper region of the tank and connected to the circulation means upstream of the chilling means for permitting inflow of water to the circulation means from the upper region at up to a predetermined flow rate; second intake means disposed within the lower region of the tank and connected to the circulation means upstream of the chilling means; outlet means connected to the circulation means downstream of the chilling means for delivering chilled water to a point of use at up to a flow rate greater than the predetermined flow rate capacity of the first intake means; inlet means for supplying relatively warm water to the upper region of the tank to replenish water withdrawn from the tank through the outlet means; and normally closed valve means associated with the second intake means for admitting water to the circulation means from the lower region of the tank when the flow rate demand on the outlet means exceeds the predetermined flow rate capacity of the first intake means.

5. A water chilling and storage system according to claim 1 wherein the valve means comprises a pressure-responsive valve that opens in response to the pressure differential created thereacross when the flow rate demand on the outlet means exceeds the predetermined flow rate capacity of the first intake means.

9. A water chilling and storage system according to claim 1 wherein: the first intake means includes a first manifold extending generally horizontally within the upper region of the tank; and the second intake means includes a second manifold extending generally horizontally within the lower region of the tank.

11. A water chilling and storage system according to claim 10 wherein: the first intake means further comprises flow restricting orifice means interposed between the first manifold and the circulation means for limiting the rate of inflow of water through the first manifold; and the valve means comprises a pressure-responsive valve interposed between the second manifold and the circulation means.

13. A water chilling and storage system comprising in combination; a tank having warm water supply inlet means for replenishing water withdrawn from the tank; a shroud having an inlet end portion extending inwardly of the tank and having an outlet end portion arranGed exteriorly of the tank; immersion chilling means arranged within the shroud for chilling water passing therethrough; chilled water withdrawal means connected into the outlet end portion of the shroud for allowing the withdrawal of chilled water from the tank at up to a given rate of flow; first water intake means disposed within an upper region of the tank and connected in flow communication with the inlet end portion of the shroud for permitting inflow of water to the shroud at up to a rate less than said given rate of flow, thereby to insure that water passing from the upper region is chilled to a desired withdrawal temperature by the chilling means; chilled water conduit means connecting the outlet end portion of the shroud in flow communication with a lower region of the tank and including pump means for normally circulating water between the tank regions successively through the shroud and the chilled water conduit means, thereby tending to establish a reservoir of water at or near said desired withdrawal temperature in at least the lower region of the tank; second water intake means disposed within the lower region of the tank and connected in flow communication with the inlet end portion of the shroud; and normally closed valve means associated with the second water intake means for admitting water therethrough to the shroud inlet end portion from the lower region whenever the flow demand rate on the chilled water withdrawal means is greater than the flow rate capacity of the first water intake means.

17. A water chilling and storage system according to claim 13 wherein the first water intake means includes separate flow restriction means for limiting the rate of flow of water therethrough.

18. A water chilling and storage system according to claim 13 wherein: the first water intake means includes an apertured upper manifold extending generally horizontally within the upper region of the tank and a first conduit connecting the upper manifold to the inlet end portion of the shroud; the chilled water conduit means includes an apertured lower manifold extending generally horizontally within the lower region of the tank; the second intake means includes a second conduit connecting the lower manifold to the inlet end portion of the shroud; and the valve means is arranged in the second circuit, whereby the valve means admits water from the lower region through the lower manifold and the first conduit to the shroud inlet end portion whenever the withdrawal demand on the chilled water withdrawal means is greater than the maximum flow rate capacity of the first intake means.

21. A water chilling and storage system according to claim 13 further comprising: by-pass conduit means, including second normally closed valve means arranged exteriorly of the tank, connecting the chilled water withdrawal means to the lower region of the tank; normally open valve means arranged exteriorly of the tank for controlling flow of water from the outlet end portion of the shroud to thE chilled water withdrawal means; and normally open valve means arranged exteriorly of the tank for controlling flow of water from the first water intake means to the inlet end portion of the shroud, whereby when the normally open valve means are closed and the second normally closed valve means is opened, the immersion cooling means may be withdrawn from the shroud without loss of water from the tank and chilled water may be withdrawn through the chilled water withdrawal means directly from the lower region of the tank.

23. A water chilling and storage system according to claim 13 wherein the valve means comprises a pressure-responsive valve that opens in response to the pressure differential created thereacross when the flow rate demand on the chilled water withdrawal means exceeds the maximum flow rate capacity of the first water intake means.

25. A water chilling and storage system comprising in combination: a chilled water storage tank including a relatively warm water supply inlet for replenishing water withdrawn from the tank; outlet means for withdrawing chilled water from said tank at up to a given rate of flow; a conduit system for normally circulating water from an upper to a lower region in the tank, the conduit system having chilling means for chilling water being circulated therethrough, thereby tending to bring the contents of the tank at least at the lower region down to a predetermined withdrawal temperature, the outlet means being connected in flow communication with the conduit system downstream of the chilling means; and first and second tank water intake means in the conduit system upstream of the chilling means, the first intake means being disposed in the upper region for supplying water to the chilling means at up to an amount below said given rate of flow and the second intake means being disposed in the lower region for supplying a flow of water from the lower region to the chilling means, whenever the flow rate demand on the chilled water outlet means exceeds said amount, at a rate accommodating for the difference between said demand rate and said amount.

26. A water chilling and storage system according to claim 25 wherein the first intake means produces a predetermined pressure differential in the conduit system relative to the tank upstream of the chilling means whenever the first intake means tends to take in water exceeding said amount due to the chilled water withdrawal demand on the outlet means exceeding said amount, and the second intake means includes normally closed valve means operable by said pressure differential.