Enhanced tankless evaporator

Abstract

Tankless evaporators, refrigeration circuits, and water coolers use a drum as a thermal mass without using one or more tanks for storing water. Water coolers can include a tankless evaporator. Also described are refrigeration circuits suitable for a water cooler and which include a tankless evaporator. An evaporator for use in a fluid chiller includes a drum of heat conductive material defining a thermal mass, a water coil disposed adjacent around the drum, an evaporator coil configured around the drum and adjacent to the water coil, in which the evaporator coil is operative to cool the water coil.

Claims

1. An evaporator for use in a fluid chiller, the evaporator comprising: a drum of heat conductive material defining a thermal mass; a water coil disposed adjacent around the drum; and an evaporator coil configured around the drum and adjacent to the water coil, wherein the evaporator coil is operative to cool the water coil; wherein the drum has a cylindrical body with an inner radius of curvature and an outer radius of curvature, wherein the difference between the outer and inner radii of curvature defines a thickness, and wherein the thickness is between one and thirty times a thickness of the water coil or of the evaporator coil in a direction normal to a longitudinal axis of the cylindrical body.

2. The evaporator of claim 1, wherein the drum comprises aluminum.

3. The evaporator of claim 1, wherein the drum comprises an aluminum alloy.

4. The evaporator of claim 3, wherein the aluminum alloy comprises 6060, 6061, or 6063 aluminum alloy.

5. The evaporator of claim 1, wherein the water coil or evaporator coil comprise C10200, C12000, or C12200 copper alloy.

6. A water cooler for dispensing cooled water, the water cooler comprising: a housing configured to receive water from a water supply; a refrigeration circuit for cooling water supplied by the water supply; wherein the refrigeration circuit includes an evaporator including, (i) a drum of heat conductive material defining a thermal mass; (ii) a water coil disposed adjacent around the drum; (iii) an evaporator coil configured around the drum and adjacent to the water coil, wherein the evaporator coil is operative to cool the water coil; and a cold-water valve configured to dispense cooled water received from the evaporator; wherein the drum has a cylindrical body with an inner radius of curvature and an outer radius of curvature, wherein the difference between the outer and inner radii of curvature defines a thickness, and wherein the thickness is between one and thirty times a thickness of the water coil or of the evaporator coil in a direction normal to a longitudinal axis of the cylindrical body.

7. The water cooler of claim 6, further comprising a heating element and hot-water valve configured to dispense hot water.

8. The water cooler of claim 6, further comprising a refrigeration circuit configured to supply the evaporator with refrigerant.

9. The water cooler of claim 8, further comprising a controller operative to control operation of the refrigeration circuit.

10. A refrigeration circuit for cooling a fluid, the circuit comprising: a compressor operative to compress a refrigerant in a conduit; a condenser; a throttling device and an evaporator, wherein the evaporator includes, (iv) a drum of heat conductive material defining a thermal mass; (v) a water coil disposed adjacent around the drum; (vi) an evaporator coil configured around the drum and adjacent to the water coil, wherein the evaporator coil is operative to cool the water coil; and wherein the drum has a cylindrical body with an inner radius of curvature and an outer radius of curvature, wherein the difference between the outer and inner radii of curvature defines a thickness, and wherein the thickness is between one and thirty times a thickness of the water coil or of the evaporator coil in a direction normal to a longitudinal axis of the cylindrical body.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) The drawings are of illustrative embodiments. They do not illustrate all embodiments. Other embodiments may be used in addition or instead. Details that may be apparent or unnecessary may be omitted to save space or for more effective illustration. Some embodiments may be practiced with additional components or steps and/or without various of the components or steps that are illustrated. When the same numeral appears in different drawings, it refers to the same or like components or steps.

(2) FIG. 1A depicts a representative prior art floor-mounted electric water cooler design; FIG. 1B depicts a representative prior art wall-mounted electric water cooler.

(3) FIG. 2 depicts a diagram of a typical refrigeration closed circuit used in water cooler applications.

(4) FIG. 3 depicts an example of a tankless evaporator in accordance with exemplary embodiments of the present disclosure.

(5) FIG. 4 depicts an alternate embodiment of a tankless evaporator in accordance with the present disclosure.

(6) FIG. 5 depicts a further embodiment of a tankless evaporator in accordance with the present disclosure.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

(7) Illustrative embodiments are now described. Other embodiments may be used in addition or instead. Details that may be apparent or unnecessary may be omitted to save space or for a more effective presentation. Some embodiments may be practiced with additional components or steps and/or without various of the components or steps that are described.

(8) An aspect of the present disclosure is directed to and provides a tankless evaporator for use in a refrigeration circuit. Exemplary embodiments of the present disclosure include water coolers having a tankless evaporator.

(9) FIG. 3 depicts a tankless evaporator 320 in accordance with exemplary embodiments of the present disclosure. Evaporator 320 includes two coils 321 and 322 for a to-be-cooled fluid (e.g., water) and a refrigerant, respectively. An optional capillary tube thermostat well 323 is shown. Evaporator 320 includes a drum 324 and the coils 321, 322 are wrapped around the drum 324. The coils 321 and 322 are preferably made of a high-thermal conductivity metal or alloy such as copper, etc. In preferred embodiments, coils 321 and 322 can be made of C10200, C12000, or C12200 copper alloy; other alloys may of course be used within the scope of the present disclosure. Evaporator 300 can be used, e.g., in refrigeration circuits, and in preferred embodiments can be used in water coolers.

(10) The drum 324 provides a structure for the coils 321, 322 to be placed or wrapped around. The drum 324 also provides a significant thermal mass for cold thermal storage (effectively a thermal sink). As shown, the drum 324 is relatively thick compared to the tubing (e.g., the outer diameter or width) used for the coils 321, 322. The drum is preferably made of a thermally conductive material having a high volumetric specific heat, e.g., aluminum and/or others suitable metal(s) or metal alloy(s). In preferred embodiments, an aluminum 6060, 6061, or 6063 alloy is used for drum 324; other metals and/or alloys may of course be used within the scope of the present disclosure. In preferred embodiments, drum 324 may have a thickness of between one-quarter (0.25) inch to three (3) inches (in direction of its radius of curvature) or may have a thickness between one (1) and thirty (30) times that (e.g., the outer diameter or width) of one of the coils in a direction normal to the drum's longitudinal axis or center line. In exemplary embodiments, the drum is one (1) inch in thickness, 1.25 inches in thickness, 1.5 inches in thickness, or 1.75 inches in thickness; other thicknesses are within the scope of the present disclosure.

(11) With continued reference to FIG. 3, in contrast with some prior art evaporators, the inner coil 321 is selected as the water coil, and the outer coil 322 is selected as the refrigerant coil. In operation, as the water in coil 321 is chilled by the refrigerant in coil 322, the drum 324 is also cooled. If the temperature of drum 324 is allowed, e.g., controlled, to drop below the temperature of the supply water in coil 321, drum 324 will serve to assist the refrigerant (in coil 322) in cooling the water coil 321. This presents an advantage over prior water coolers since the refrigeration system in typical prior art electric water coolers operate to cool at a rate which is less than the flow rate of water out of the system, i.e., those prior art systems cannot cool the incoming water as fast as the water enters and leaves the system.

(12) As a result of the configuration of the coils and the cooling mass of drum 324, the drum 324 serves to improve the cooling rate afforded by the evaporator, e.g., during conditions of unsteady-state demand. The refrigerant being in the outside coil 322 also further assists heat transfer of the evaporator 320 because in operation the outer coil 322 will shrink more than the water 321 coil due to coil 321 being the colder of the two. This will press the coils more tightly together. Consequently evaporator 320 is able to remedy, ameliorate, or overcome many or all of the deficiencies noted previously for prior art designs.

(13) FIG. 4 shows an alternate embodiment 400 of an evaporator in accordance with the present disclosure. Inner and outer coils 401, 402 are configured in a coiled relationship with a drum 404 and in operation convey water and refrigerant, respectively. As shown, inner coil 401 can be made of larger tubing—having a greater cross-sectional area 401a—than the cross-sectional area 402a of the outer coil 402. In exemplary embodiments, the coils 401, 402 can be formed in such a way that their heights (direction parallel to the longitudinal axis of drum 404) are equal or nearly equal so that the coils have the same number of wraps (full or partial coil revolutions) around the drum 404. A configuration such as shown in FIG. 4 can provide for an increased volume of cooled water compared to prior art designs, e.g., approximately 40-50% more volume.

(14) FIG. 5 depicts a further embodiment of a tankless evaporator 500 in accordance with the present disclosure. Evaporator 500 includes a drum 501 as well as inner and outer coils 502 and 503. The center line (longitudinal axis) of drum 501 is indicated. As shown, inner coil 502 is formed, e.g., cast, in the drum 503. The outer surface of the drum 501 can be configured to receive or hold the outer could 503; for example, the outer surface of the drum 501 can be machined or cast to have spiral grooves for holding the outer coil 503 when wrapped about the drum 501. Internally grooved/finned tubing may optionally be used for the refrigerant coil in the configuration shown.

(15) Accordingly, it will be appreciated that embodiments of evaporators, refrigeration circuits, and water coolers in accordance with the present disclosure can offer numerous advantages and benefits relative to prior art designs.

(16) The components, materials, steps, features, objects, benefits, and advantages that have been discussed are merely illustrative. None of them, nor the discussions relating to them, are intended to limit the scope of protection in any way. Numerous other embodiments are also contemplated. These include embodiments that have fewer, additional, and/or different components, materials, steps, features, objects, benefits, and/or advantages. These also include embodiments in which the components, materials, and/or steps are arranged and/or ordered differently.

(17) For example, the drum can be anodized to facilitate reduction or elimination of galvanic corrosion between different metals or metal alloys, e.g., between aluminum of a drum when in contact with copper of a coil. Sensor locations (such as for one or more types of temperature sensors) can be added in addition to or substitution for the capillary tube thermostat well, when present. Additional wraps (coils) of the tubes (conduits) can be added. The inner coil shape can be modified, and/or the drum outer surface can be shaped so as to conform or better conform to the surface of the inner coil. The control system could be set up so that the refrigeration system is turned on after a certain amount of demand time has been incurred, e.g., the water cooler or “bubbler” has been operated for a specified amount of time, e.g., 15 seconds, etc. This latter feature can be used to improve performance because cooling of the water can begin at a specified time without having to wait for the capillary tube thermostat to trigger cooling.

(18) Further, the outer coil shape and/or inner coil shape could be modified to conform better to each other. The refrigerant and water coils can be switched so that the refrigerant coil is on the inside. In some embodiments, a stainless steel coil could be cast into the material of the drum, e.g., aluminum, and the water could be run through both the copper and stainless steel tubes; any other suitable corrosion-resistant material could be used in place of stainless steel. As noted previously, the inner coil can be made of larger tubing (or conduit) than the outer coil. For example, the inner coil may be formed to have a geometry with a greater depth (or width)—e.g., referring to the extent of the coil in a radial direction relative to the longitudinal axis of an adjacent drum—than an adjacent outer coil but with the same height as the outer coil, such that their heights (and therefore number of wraps about an adjacent drum) are still consistent. In other embodiments, the coils may instead made of tubing or conduit with different heights (relative to the drum and its center line or longitudinal axis). Internally grooved/finned tubing can be used for a refrigerant coil. Further, the structures described (coils and/or drum) may each be made from composite or multiple-components materials, within the scope of the present disclosure. For example, a drum may have aluminum and copper portions, copper and stainless steel portions, aluminum and stainless steel portions, etc. Other materials may be used stead of or in addition to those that have been described. Further, a tankless evaporator can be used in either a closed refrigeration circuit or an open one.

(19) Moreover, while refrigerant and water tubing have been described herein and shown in the drawings in the context of surrounding the drums in circular spirals, any other suitable geometries can be used for configuring the tubing relative to a drum. For non-limiting example, the water and/or refrigerant tubing may be configured in rectilinear patterns over the surface of a drum. Furthermore, the configuration of one type of coil (or tubing) can be different than that of another type, and two or more coils can be used for each type of coil instead of a single coil as provided in the description above. For example, in some embodiments, a water coil can be wound in a circular spiral around a drum, while the refrigerant coil can be configured around the drum and/or water coil in a rectilinear, e.g., space-filling, configuration. Moreover, each type of coil may have multiple different configurations. For example, a refrigerant coil may have a circular spiral configuration that extends over a water coil to areas on a drum above and below the area on the drum's outer surface that is covered by the water coil; above and below the water coil, the refrigerant coil may have one “pitch,” or two different pitches, respectively, which is/are different than a pitch used for the section of coil covering the water coil. Separate coils may be used respectively for each separate section but that is not required.

(20) Unless otherwise stated, all measurements, values, ratings, positions, magnitudes, sizes, and other specifications that are set forth in this specification, including in the claims that follow, are approximate, not exact. They are intended to have a reasonable range that is consistent with the functions to which they relate and with what is customary in the art to which they pertain.

(21) All articles, patents, patent applications, and other publications that have been cited in this disclosure are incorporated herein by reference.

(22) The phrase “means for” when used in a claim is intended to and should be interpreted to embrace the corresponding structures and materials that have been described and their equivalents. Similarly, the phrase “step for” when used in a claim is intended to and should be interpreted to embrace the corresponding acts that have been described and their equivalents. The absence of these phrases from a claim means that the claim is not intended to and should not be interpreted to be limited to these corresponding structures, materials, or acts, or to their equivalents.

(23) The scope of protection is limited solely by the claims that now follow. That scope is intended and should be interpreted to be as broad as is consistent with the ordinary meaning of the language that is used in the claims when interpreted in light of this specification and the prosecution history that follows, except where specific meanings have been set forth, and to encompass all structural and functional equivalents.

(24) Relational terms such as “first” and “second” and the like may be used solely to distinguish one entity or action from another, without necessarily requiring or implying any actual relationship or order between them. The terms “comprises,” “comprising,” and any other variation thereof when used in connection with a list of elements in the specification or claims are intended to indicate that the list is not exclusive and that other elements may be included. Similarly, an element proceeded by an “a” or an “an” does not, without further constraints, preclude the existence of additional elements of the identical type. The abstract is provided to help the reader quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. In addition, various features in the foregoing detailed description are grouped together in various embodiments to streamline the disclosure. This method of disclosure should not be interpreted as requiring claimed embodiments to require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disclosed embodiment. Thus, the following claims are hereby incorporated into the detailed description, with each claim standing on its own as separately claimed subject matter.