US20150233626A1

US20150233626A1 - Air Conditioning Condenser Attachment for High Efficiency Liquid Chillers

Info

Publication number: US20150233626A1
Application number: US14/624,275
Authority: US
Inventors: Stephen Keen
Original assignee: SURNA Inc
Current assignee: SURNA Inc
Priority date: 2014-02-17
Filing date: 2015-02-17
Publication date: 2015-08-20

Abstract

Provided herein are high-efficiency liquid chiller systems and related methods for efficient climate control of a room environment. A split-system air conditioning (AC) unit is connected to a liquid chiller positioned within an enclosure and adjacent to the AC unit. Refrigerant from the AC unit is used to cool a liquid via a heat exchanger positioned in the enclosure. The cooled liquid is, in turn, supplied to a downstream cooling application. In a closed-loop manner, warmed refrigerant is returned to the AC unit for cooling and warmed liquid returned to the heat exchanger for cooling in the heat exchanger. A reservoir in thermal contact with the cooled liquid may be used as a source of chilled liquid for any number of various cooling applications, including via air handlers positioned in distinct locations.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims benefit of U.S. Provisional Patent Application No. 61/940,578 filed on Feb. 17, 2014, which is herein incorporated by reference in its entirety to the extent not inconsistent herewith.

BACKGROUND OF THE INVENTION

The devices, systems and methods provided herein relate to the field of refrigerant based liquid chillers, including an attachment to a standard air conditioning condenser which can turn any traditional a/c compressor and condenser unit into a high efficiency liquid chiller.
There are many known ways to construct a liquid chiller, and many different manufacturers of such devices. While the applications vary, nearly all include a refrigerant compressor (to compress refrigerant leaving the evaporator in gas form into the condenser), the condenser (where BTU's are removed from refrigerant and refrigerant is condensed into liquid form), and the evaporator (where BTU's are removed from the liquid medium being cooled and absorbed into the refrigerant, returning it to gas form). Some chillers use air cooled condensers, and some are cooled by water. There are also multiple different types of evaporators (brazed plate and coil evaporators are most common). Traditional air conditioners work similarly, with the evaporator (usually in the form of an air handler) operating as an air to refrigerant heat exchanger, where BTU's are removed from air, while the evaporator in a chiller is a liquid (usually water or a water/glycol mix) to refrigerant heat exchanger, removing BTU's from liquid. Chillers for commercial use are typically much more expensive than air conditioners with the same or similar heat capacity, even though many of their components are the same.
The present invention utilizes the low cost and easy availability of traditional air conditioner condensing units to create a high capacity liquid chiller at a lower price point than other chillers currently available, in a robust, flexible, and easily operated manner.

SUMMARY OF THE INVENTION

Provided herein is a high efficiency liquid chiller system and related methods that include a split-system air conditioning (AC) unit and a liquid chiller contained within an enclosure which utilizes the condenser unit of the air conditioner to chill liquid. The chilled liquid can then be used, directly or indirectly, in any application where cooling or temperature control is desirable. Advantageously, the present invention reduces the linear distance the refrigerant must be pumped by the split-system air conditioning unit through the closed loop of the refrigeration system, thus increasing energy efficiency and decreasing the mechanical strain and wear on the air conditioning unit and components thereof. The liquid chillers provided herein also represent a significant reduction in volume or physical footprint occupied in comparison with conventional industrial chiller units with attendant benefits. The functional benefits achieved by the special configuration, layout and packaging of the liquid chiller components within the enclosure include ease of installation, scale-up, redundancy protection, lower cost and attendant cost savings associated with decreased maintenance, up-keep and energy use.
The systems and methods provided herein utilize conventional AC components, including a compressor and condenser, that circulate a cooling medium, referred herein as a “refrigerant”. The cooled refrigerant is then used to cool, in turn, a liquid, such as water or a glycol-water mixture. The energy-efficiencies of the instant system relate to the liquid having a good heat capacity, that can be subsequently transported in a highly thermally efficient manner for temperature control or, as desired, for cooling of a liquid reservoir. This reservoir is functionally equivalent to a battery that stores energy, except in this case the cooled liquid in the reservoir corresponds to stored cooling energy that can then be used on-demand, independent of the AC unit. The cold liquid in the reservoir can be pumped from the reservoir to various locations having suitable air-handlers and thermostats for efficient cooling. In this manner, cooling of a localized environment, such as a room, is achieved without having to directly engage the AC unit positioned outside the room or building. Instead, the AC unit maintains the reservoir at a low temperature and, independently, systems downstream of the reservoir provide desired cool liquid flow from the reservoir, as desired.
Furthermore, a single AC unit can then be used, indirectly, to cool various rooms via multiple air handlers positioned downstream of the cooled reservoir. This greatly increases flexibility and ease of install, in a low-cost and simple manner and is particularly amenable for incorporation of back-up or redundancy systems. For example, a plurality of AC units may be operably connected for liquid cooling to a cooled liquid reservoir. Similarly, a plurality of chillers may be incorporated to accommodate any short-term failure, so that an idle chiller can be automatically engaged, ensuring there is no loss of cooling to the building.
Additional advantages of liquid-chiller systems include the higher heat capacity of water compared to air. Accordingly, a chilled-liquid system can provide constant dehumidification to a room, even when compressors are not running, so that humidity spikes are avoided. Furthermore, the thermal conductivity and heat capacity of water is much higher than air. The functional importance of this is that the liquid (e.g., water) increases temperature at one-quarter the rate of air when the same amount of BTU's are absorbed, so that water can remove four times as many BTU's as air, 20 times faster than air, significantly decreasing electricity usage, while providing a more accurate and controllable environment. Accordingly, not only are the liquid chiller systems provided herein comparable in price to HVAC systems, but there are significant cost savings in the form of lower electricity usage.
The cooling from the reservoir or chiller can be in a closed-loop system, thereby avoiding open input associated with conventional forced-air systems. This decreases the risk of unwanted introduction of foreign objects, such as pests to an agricultural facility. In an aspect, all the fluid conduit loops described herein are in a closed-loop system, meaning there is no way for any liquid or vapor to escape to the external environment.
The systems are readily expandable by simply connecting additional compressors to the fluid reservoir, with additional water lines plumbed to new areas requiring cooling, without having to redesign the entire cooling system. Instead, the systems provided herein are modular in design, allowing for quick and easy expansion as cooling needs increase. This is a significant cost benefit.
The systems and methods provided herein can operate over a large temperature range, such as from 120° F. to −20° F. The low temperature operation may be through the use of a compressor heater so that the chiller remains in operation without damage associated with freezing temperatures. Where freezing temperatures are expected, the liquid being cooled by the refrigerant may be water with an anti-freeze component to provide a freezing temperature that is lower than that of the surrounding environment. For warmer climates, the liquid can be water. For inside a climate controlled building where freezing temperatures will not occur, the reservoir may be water. The reservoir may be highly insulated to minimize passive heating of the liquid in the reservoir from the surrounding environment.
In an embodiment, the invention comprises a high efficiency liquid chiller system comprising: (i) A split-system air conditioning unit comprising a condenser unit, a condenser outlet thermally connected to the condenser unit for providing a source of chilled refrigerant from the condenser unit, and a condenser inlet thermally connected to said condenser unit for providing a source of refrigerant to be cooled by the condenser unit; (ii) an enclosure having a chiller enclosure volume; (iii) a liquid chiller positioned in the chiller enclosure volume, the liquid chiller comprising a refrigeration conduit comprising a refrigeration inlet and a refrigeration outlet, a liquid conduit comprising a liquid inlet and a liquid outlet, and a heat exchanger that thermally connects the refrigeration conduit and the liquid conduit; (iv) an inlet refrigeration line that fluidically connects the condenser outlet to said liquid chiller refrigeration inlet; and (v) an outlet refrigeration line that fluidically connects the liquid chiller refrigeration outlet to the condenser inlet, wherein the inlet and outlet refrigeration lines are configured to position the enclosure adjacent to the split-system air conditioning unit with a separation distance that is less than or equal to 1 meter or, optionally, greater than or equal to 1 cm and less than or equal to 50 cm. In certain embodiments, for example, the separation distance is less than or equal to 10 cm.
In some embodiments, for example, the enclosure is in physical contact with an outer surface of the split-system air conditioning unit. In embodiments, the separation distance is less than or equal to a length of the inlet refrigeration line or the outlet refrigeration line that runs between the enclosure and AC unit surface. In some embodiments, the inlet refrigeration line and the outlet refrigeration line have an independently defined lumen diameter, for example, that is greater than or equal to ¼″ and less than or equal to 1″. In embodiments, the inlet refrigeration line has a length that is less than or equal to 2 m, 1 m, or 50 cm and, optionally, the outlet refrigeration line has a length that is less than or equal to 2 m, 1 m, or 50 cm. In an aspect, the refrigeration lines are curved to provide reliable access to the chiller inlet and outlet in a compact, low footprint configuration. In an aspect, the lines have two 90° bends separated by a straight-line portion that spans the separation distance, such as that is less than about 1 m, 0.5 m or 0.1 m.
The systems and methods of the present invention are compact and durable. The chiller enclosure is designed to minimize both the volume and footprint required by the liquid chiller system while maintaining a high cooling capacity. The chiller enclosure may optionally be enclosed to protect internal components and provide insulation.
In an aspect, the enclosure is substantially rectangular-shaped having six faces defined by a length, a width and a depth, the six faces corresponding to: (a) opposibly facing top and bottom faces; (b) opposibly facing left and right side faces; and (c) opposibly facing front and rear faces. Optionally, in some embodiments, the enclosure is formed of a solid material with four access passages on one of the left or right side faces that provide fluidic access to the refrigeration conduit and the liquid conduit, optionally, so that the separation distance is less than the inlet refrigerant line length and less than the outlet refrigerant line length, including a straight-line portion thereof. In certain embodiments, for example, the enclosure volume is less than or equal to 30,000 cm³, 20,000 cm³or 10,000 cm³. For example, the enclosure may be characterized as having a height (H), width (W) and depth (D). The height may be less than 25″; the width less than 12″, and the depth less than 6″. In an aspect, the inner surface of the enclosure is in a tight-fit configuration with respect to an outermost surface of the heat exchanger. In an aspect, there is a small separation distance between the outer surface of the heat exchanger and the inner surface of the enclosure, such as less than an average of 10 cm, less than an average of 5 cm, or less than an average of 1 cm, from the nearest surface of the chiller component. In this manner, both the enclosure and heat exchanger may be supported, directly or indirectly, from one or more conduits that connect to the AC unit. Optionally, the enclosure may be at least partially supported by or entirely supported by the ground.
In certain embodiments, the liquid chiller provides a cooling capacity that is greater than or equal to 10,000 BTU/hr, or 20,000 BTU/hr, or between 30,000 BTU/hr and 320,000 BTU/hr. In some embodiments, the rear face of the enclosure is opposibly configured to an outer surface of the split-system air conditioning unit and separated from the outer surface by the separation distance. The enclosure may be positioned relative to an outer surface of the AC unit, such that refrigerant inlet/outlet ports are aligned with condenser inlet and outlet ports. For example, for enclosure inlet/outlet ports on the right face of the enclosure, the right face may be aligned to correspond to the position of the condenser inlet/outlet ports on the AC unit. Furthermore, the enclosure dimensions may be defined in terms of the AC unit dimensions, such as enclosure height, width and/or depth that is between 50%-80%, 25%-60%, and/or less than 25% of the respective AC unit dimension.
The systems and methods provided herein are versatile and capable of combination with a wide variety of additional components and enhancements. In an aspect, the system further comprises one or more of: a liquid thermostat control connected to the liquid conduit to control temperature of liquid in the liquid conduit; a temperature sensor connected to the liquid conduit or the refrigerant conduit for measuring temperature; an expansion bypass valve connected between the refrigerant inlet conduit and the heat exchanger that fluidically connects to the refrigerant outlet conduit to bypass the heat exchanger; a fan cycle switch to cycle a condenser fan of an air conditioning compressor based on the refrigerant pressure in the refrigerant inlet conduit; a liquid flow switch to shut off an air conditioning compressor during a low liquid flow condition; a refrigerant bypass line that fluidically connects the refrigerant inlet conduit and the refrigerant outlet conduit to fluidically bypass the heat exchanger; a low pressure switch to stop flow during a low refrigerant pressure condition; or a thermobulb and thermobulb capillary connected to an expansion bypass valve, wherein the thermobulb is fluidically connected to an exiting high pressure and high temperature refrigerant location and increases and decreases in temperature of exiting refrigerant, to provide thermobulb expansion and contraction and an open or close condition of the expansion bypass valve, to compensate for an adverse temperature condition.
In some embodiments, the system further comprises a refrigerant in the refrigeration line and conduit and a liquid in the liquid line and conduit, wherein the refrigerant comprises a blended hydrofluorocarbon mixture and the liquid comprises water or, optionally, a mixture of water and anti-freeze, such as water and glycol. In certain embodiments, the system further comprises an electrical system control, wherein the electrical system control is electrically connected to the condenser unit. In certain embodiments, the chiller has a volume less than or equal to 60%, or optionally 70%, or optionally 80%, of a traditional industrial cooler with equivalent cooling capacity. In this manner, the chiller may be conveniently packaged and positioned adjacent to, and supported by, the AC unit.
In some embodiments, the system further comprises a chilled-liquid reservoir fluidically and/or thermally connected to a chiller liquid conduit outlet, optionally, the chilled liquid reservoir has a volume that is less than or equal to 5 gallons per ton of cooling capacity. In embodiments, the system further comprises a pump fluidically connected to the liquid conduit to provide a controlled fluid flow rate through the chiller heat exchanger, wherein the pump has a reduced pump size in view of the more efficiently sized chiller and heat exchanger. In certain embodiments, the system has a liquid flow rate to the chiller that is greater than or equal to 2.3 GPM/ton of cooling capacity and less than or equal to 2.6 GPM/ton of cooling capacity, with an accordingly sized pump. Optionally, in some embodiments, the system further comprises a flow-meter fluidically connected to the fluid conduit to measure flow-rate of a liquid through the chiller. The chilled liquid from the chiller may be in a closed loop system with respect to the reservoir, such as via a heat exchanger. Alternatively, the chilled liquid from the chiller may dump into the reservoir, and the return loop may be liquid removed from the reservoir, such as after or during thermal mixing of the liquid in the reservoir. In an aspect, any of the systems provided herein comprise a 10-ton chiller or a 25-Ton chiller, and subranges thereof.
In an aspect, the invention includes a method of providing chilled liquid for a cooling application comprising the steps of: (a) providing an enclosed liquid chiller that is fluidically connected to a split-system air conditioning unit, where in the liquid chiller enclosure is separated from the split-system air conditioning unit by a separation distance that is less than or equal to 1 m, less than or equal to 2 m, or between about 1 cm and 50 cm and subranges thereof, such as between 2 cm and 20 cm; (b) cooling a refrigerant with a condenser unit of the split-system air conditioning unit to provide chilled refrigerant; (c) introducing the chilled refrigerant to a heat exchanger of the liquid chiller; (d) cooling a liquid in thermal contact with the heat exchanger with the introduced chilled refrigerant thereby generating cooled liquid and heated refrigerant; (e) removing heated refrigerant from the heat exchanger; (f) introducing the heated liquid to the condenser unit; and (g) thereby providing chilled liquid for a cooling application. In some embodiments, the cooling application comprises an indoor agricultural facility and the cooled liquid is stored in a reservoir for on-demand cooling in a closed-loop configuration.
In an aspect, the invention provides a method of making a high-efficiency liquid chiller comprising the steps of: (a) enclosing a liquid chiller within an enclosure; (b) providing a pair of inlet ports and a pair of outlet ports through the enclosure; (c) providing a refrigerant inlet and refrigerant outlet port through a surface of the enclosure; (d) fluidically connecting the refrigerant inlet and outlet ports to a condenser unit of a split-system air conditioning unit; wherein the enclosure has a volume that is less than or equal to 30,000 cm³and a separation distance from an outer surface of the split-system air conditioning unit that is less than or equal to 0.1 m. In this manner, the system may be shipped to the customer or end-user in an already-connected configuration for efficient and easy on-site installation.
Any of the methods and systems provided herein may be used with an indoor agricultural facility, where plants are grown in a desirably controlled environment. In this aspect, the use with an indoor agricultural facility may further comprise the steps of: thermally contacting the chilled liquid with a reservoir to provide a reservoir of cooled liquid for on-demand cooling of the indoor agricultural facility; and returning warmed liquid from the thermally contacting step to the heat exchanger of the liquid chiller.
In some embodiments, the method further comprises: (a) fluidically connecting an inlet refrigerant conduit to a condenser unit of the split-system air conditioning unit and to an inlet of a heat exchanger in the liquid chiller, wherein cold refrigerant from the condenser unit is introduced via the inlet refrigerant conduit to the heat exchanger for cooling of the liquid in the heat exchanger; and (b) fluidically connected an outlet refrigerant conduit to an outlet of the heat exchanger and to an inlet of the condenser unit for returning heated refrigerant from the heat exchanger to the condenser unit for cooling and subsequent introduction to the inlet refrigerant conduit.
The fluidically connecting step may comprise fluidically connecting an inlet refrigerant conduit to a condenser unit of the split-system air conditioning unit and to an inlet of a heat exchanger in the liquid chiller, wherein cooled refrigerant from the condenser unit is introduced via the inlet refrigerant conduit to the heat exchanger for cooling of the liquid in the heat exchanger; and fluidically connecting an outlet refrigerant conduit to an outlet of the heat exchanger and to an inlet of the condenser unit for returning heated refrigerant from the heat exchanger to the condenser unit for cooling and subsequent introduction to the inlet refrigerant conduit. For example, the reservoir functionally acts as a store of cooled energy, that can be supplied to an air handler having a radiative-type exchanger, such as air blowing over a heat exchanger in which cold water is flowed. After flowing warm air over such a heat exchanger, cold air may be used for temperature control in the room and the warmed water returned to the reservoir for subsequent cooling in a repetitive-type manner. Accordingly, any of the systems and methods provided herein further comprise an air handler, including any of those available by SURNA INC. (Boulder, Colo.), surna.com/product-item/air-handlers/, which is specifically incorporated by reference for the ceiling-mounted and multi-position air handlers described therein.
Any of the methods or systems provided herein can be further described in terms of one or more parameters of interest, including one or more of: conduit and/or line lengths that are short, such as less than about 2 m or less than about 1 m; cooling capacity of between about 20,000 BTU/hr and less than or equal to 320,000 BTU/hr, including in terms of the volume of the enclosure, such as a BTU/hr/cm³, including better than 1 BTU/hr/cm³of enclosure volume; energy requirement that is not significantly greater than that required to run a conventionally sized AC unit, such as within about 30%, within 20% or within 10%.

DESCRIPTION OF THE DRAWINGS

FIG. 1: Schematic illustration of the process and instrumentation of the liquid chiller within the enclosure containing the liquid chiller.

FIG. 2: Exemplary liquid chiller configuration with enclosure removed.

FIG. 3: Three views of the liquid chiller: top view (top panel); side view (bottom left panel); and front view (bottom right panel). The dimensions are in inches.

FIG. 4: Schematic illustration of the invention including the split-system air conditioning unit and chiller enclosure with exemplary connections.

FIG. 5: Perspective view of the high efficiency liquid chiller, illustrating the enclosure with liquid chiller that is adjacent to the split-system air conditioning unit

FIG. 6: Schematic of the downstream components, wherein liquid in a reservoir is cooled for on-demand cooling, independent of having to engage the upstream AC unit.

FIG. 7: Flow diagram of method of providing chilled liquid for a cooling application.

FIG. 8: Flow diagram of method of making a high-efficiency liquid chiller.

DETAILED DESCRIPTION

In general the terms and phrases used herein have their art-recognized meaning, which can be found by reference to standard texts, journal references and contexts known to those skilled in the art. Referring to the drawings, unless indicated otherwise like numerals indicate like elements and the same number appearing in more than one drawing refers to the same element. The following definitions are provided to clarify their specific use in the context of the invention.
“Split-system air conditioners” refer to an air conditioning unit that comprises two separate portions, a first portion sometimes referred to as an outdoor portion comprising a condenser unit and a heat exhaust which provides refrigerant via a refrigeration line, often several meters, to a second portion, sometimes referred to as an indoor portion, that utilizes cooled refrigerant from the first portion for cooling of air inside of a structure. As used herein, “split-system air conditioning unit” refers to the first portion of the system containing the condenser for use with a liquid chiller portion of the instant invention. In some embodiments, the second portion may be used in conjunction with the enclosed liquid chiller to provide a source of cool air as well as cool water. In embodiments, the second portion is positioned at least partially outdoors or outside of an environment to-be-cooled, adjacent to the first portion. In other words, there are two thermal transfer mechanisms that occur outside the to-be-cooled room, the cooling of refrigerant by the condenser in the first portion of the split AC system, and the cooling of liquid by the refrigerant that corresponds to the second portion of the split AC system. The cooled liquid from the second portion of the split AC system may, in turn, be used to provide cooling to a reservoir positioned inside a building that contains a to-be-cooled room or area, such as an insulated tank that contains a volume of liquid cooled via the liquid chiller. One advantage of the instant systems and methods are that they can be readily incorporated with any of a variety of the off-the-shelf commercial split system AC units including those systems by Trane, Rhoem, Carrier, Lennox, York and other manufacturers.
“Enclosure” refers to a three dimensionally defined enclosure volume in which chiller components are positioned in a high form factor configuration. For example, the heat exchanger, inlets and outlets to the heat exchanger, may all be tightly packed within the enclosure volume, ensuring simple, rapid and efficient connection to a refrigerant line from the AC unit and a liquid line for downstream cooling applications. High form-factor and tightly packed refer to minimal dead space volume within the enclosure, such as defined by a maximum separation distance of an outermost surface of the heat exchanger of the liquid chiller and an inner surface of the enclosure that is less than or equal to 10 cm, 5 cm, 2 cm or 1 cm. In an aspect, the inner surface of the enclosure does not physically contact the heat exchanger of the liquid chiller, to ensure there is an air buffer between the heat exchanger and the enclosure. Alternatively, the dead space volume may be described as the portion of the enclosure volume that is not occupied and that is less than 20%, less than 10%, less than 5%, or less than 1% of the total enclosure volume. Generally, the enclosure is described as solid or closed, although there are access ports for fluid introduction and exit from the heat exchanger, including an inlet/outlet pair for each the refrigerant loop and the liquid loop. In some embodiments additional openings for example including but not limited to vents, exhausts or additional inlets/outlets may be present. Alternatively, the enclosure may have a see-through portion, or a portion constructed of a mesh or screen. In an embodiment, a door or panel may be provided to facilitate access to the enclosure volume. As desired, the enclosure may contain more or less conduit length for convenient positioning for connection to and from the heat exchanger to refrigerant lines.
“Conduit” refers to hollow tube or pipe in which fluid may pass through with minimal or no fluid loss. In an aspect, conduit refers to the entire tubing or piping structure within the enclosure that is not part of the heat exchanger. “Line” is used similarly to conduit, but generally refers to those portions that are outside the enclosure. Accordingly, a single fluid passage between the heat exchanger and a relevant component (e.g., condenser) may be defined in terms of the inside enclosure portion corresponding to the conduit and the outside of the enclosure portion corresponding to the line.
“Heat exchanger” refers to a device used to transfer thermal energy from one fluid to another. The present invention is compatible with a wide range of heat exchanger geometries, so long as satisfactory thermal transfer is achieved and the heat exchanger can be efficiently positioned within the enclosure volume.
“Refrigerant” refers to a fluid with specific thermodynamic properties that allows for efficient use within a refrigeration cycle. Within a refrigeration cycle, a refrigerant will generally change phases between a gas and a liquid.
“Adjacent” in the context of the enclosure portion with respect to the AC unit, refers to a position that is in the vicinity of the AC unit, but not necessarily in physical contact. Adjacent may have a functional definition, such as the enclosure and the chiller portions therein, that can be supported by the AC unit solely by the conduits that fluidically connect the AC unit with the chiller. This has the functional benefit of the unit that can be constructed and provided to the customer in one integral piece, with the chiller already connected to the split-system AC unit. This may be an important distinction with conventional systems, where the second portion is installed separately from the AC unit, such as far away inside a building, including many meters or more away from the AC unit. Accordingly, an alternative definition of adjacent is by absolute distance values, such as less than 1 m, less than 50 cm, less than 10 cm, less than 5 cm, or less than 1 cm. In an aspect, any of the liquid chiller systems provided herein are shipped to an end user as an integral unit with the lines connecting the condenser to the enclosure and chiller pre-placed. In this manner, the installation requirement is electrical hook-up of the split AC unit and plumbing line connection of the liquid conduit inlet and outlet to the liquid lines extending from the cooling application of interest. One particularly useful cooling application of interest is cooling of a liquid-containing reservoir inside or outside a building. That cooled reservoir can then be connected in turn, to any number of locations of active environmental cooling, such as air-handlers or the like in combination with room thermostat controllers. The cooled liquid itself may be directly stored in the reservoir, or may be used to indirectly chill fluid in the reservoir.
“Separation distance” refers to the shortest distance between the split-system air conditioning unit and the enclosed liquid chiller and, as described above, can be used as a quantitative description of adjacent.
“Operably connected” refers to a configuration of elements, wherein an action or reaction of one element affects another element, but in a manner that preserves each element's functionality. For example, a heat exchanger operably connected to a refrigerant line refers to flow of refrigerant from the line to the heat exchanger to provide desired thermal transfer without affecting the fluid integrity of the line, connecting elements or the heat exchanger.
“Fluidically connected” refers to a fluid or fluid property being able to transit, either under a bulk flow or by diffusion, between components without impacting the desired function of the components.
“Thermally connected” refers to heat being able to transit or transfer between components, without impacting the desired function of the components.
“Traditional industrial chiller” refers to a chiller that does not have the chiller portion adjacent to the AC unit, but instead the chiller portion is positioned inside a building, for example, with the AC unit that is outside the building. In this aspect, the system may be described in terms of a decrease in the volume of the refrigerant lines that connect the heat exchanger of the chiller to the condenser of the AC unit, such as a decrease in at least 70%, at least 50%, or at least 30% of the length. This decrease in length also decreases the total volume of refrigerant required to fill the refrigerant closed loop system, by a corresponding amount.

Example 1

High-Efficiency Liquid Chiller System

FIG. 1 is a schematic illustration of the liquid chiller enclosure 107. Liquid enters the enclosed liquid conduit 100 via the liquid inlet 102. At the same time, refrigerant flows in a closed loop from the condenser unit of a split-system air conditioning unit (not shown) through the enclosed refrigerant conduit 101 entering via the refrigeration inlet 104 and exiting the enclosure back toward the condenser unit through the refrigeration outlet 105. Accordingly, both the liquid conduit and the refrigerant conduit form part of respective closed loop systems. The liquid and refrigerant thermally interact within the heat exchanger 106 thereby cooling the liquid and heating the refrigerant. The liquid is removed from the chiller through the liquid outlet 103. Several optional features are included in this embodiment including an expansion bypass valve 109 which connects to a refrigeration bypass line 116. An optional thermobulb 112 and thermobulb capillary 113 are also shown. Additional optional features include: a liquid temperature sensor 110 which may be attached to a temperature controller via an electrical wire 111 to adjust the temperature of the chilled liquid; a low pressure switch 108 to shut of the air conditioner during a low liquid flow condition; a fan cycle switch 115 which may be connected to the air conditioning unit; and a flow switch 114 for adjusting the flow rate of the liquid through the liquid chiller.
FIG. 2 illustrates the liquid chiller with the enclosure removed for visualization of a portion of the chiller positioned in the enclosure volume. The liquid conduit 200 is shown with liquid inlet 202 and the liquid outlet 203 which extend outside of the enclosure as part of liquid lines that may connect to and from a cooling reservoir. Similarly, the refrigeration conduit 201 is shown with refrigeration inlet 204 and refrigeration outlet 205 which also would extend outside of the enclosure as part of refrigeration lines to fluidically connect to the condenser. Both conduits enter and exit the heat exchanger 206 in which the liquid is chilled by heating refrigerant supplied by the refrigerant line and conduit. The refrigeration bypass valve 209 and refrigeration bypass line 216 are also illustrated. The thermobulb 212 is shown with attached thermobulb capillary 213 which connects the refrigeration outlet to the refrigeration inlet. Exemplary locations for mounting a low pressure switch 208 a temperature sensor 210, the liquid flow switch 214 and fan cycle switch 215 are also illustrated.
FIG. 3 is a scale schematic top view (top panel); side view (bottom left panel); and front view (bottom right panel) of the liquid chiller with the enclosure removed and demonstrates the small dimension and compact size of the chiller. All dimensions are in inches. The liquid conduit 300 and refrigerant conduit 301 are shown with liquid inlet 302, liquid outlet 303, refrigeration inlet 304 and refrigeration outlet 305. The refrigeration bypass valve 309 allows refrigerant to flow through the refrigerant bypass line 316 in which refrigerant does not pass through the heat exchanger 306 but instead flows to the refrigerant outlet and back into the condenser unit of the air conditioner. The thermobulb 312 connects the liquid outlet with the refrigeration inlet via the thermobulb capillary 313. Other components may include a low pressure switch 308; a fan cycle switch 315; and a flow switch 314.
FIG. 4 is one embodiment illustrating connection between the enclosed liquid chiller 407 and the split-system air conditioning unit 420. The condenser unit 423 located within the air conditioning unit has a condenser outlet 422 which is fludically connected to an inlet refrigeration line 430 which in turn is fludicially connected to the refrigeration inlet 404. Additionally, the refrigeration outlet 405 is fluidically connected to the condenser inlet 421 by the outlet refrigeration line 431. Refrigerant may then flow through the enclosed liquid chiller via the refrigeration conduit 401 and the heat exchanger 406 in a closed loop configuration, exiting the refrigeration outlet and returning to the condenser unit where it may be cooled. In some embodiments, an electrical system control 417 is electrically connected to the electrical system of the air conditioning unit by one or more electrical wires 418. The liquid enters the chiller in the liquid inlet 402 via liquid line 448, flows through the liquid conduit 400 and heat exchanger 406, then exits the chiller at a lower temperature from the liquid outlet 403 to the liquid outlet line 449 for use in a downstream cooling application, indicated schematically as 450. As desired, cooling application 450 may correspond to a fluid reservoir (see, e.g., FIG. 6), having an outlet corresponding to liquid line 448 so that the warmed liquid can then be cooled via a repeat of the process. The enclosure that is adjacent to the AC unit may be defined in terms of a separation distance 460.
FIG. 5 illustrates an enclosure 107 that is rectangularly shaped and connected to the split-system AC unit 420. The connections between the enclosure and AC unit include inlet and outlet refrigerant lines (430 431). Liquid inlet and outlet (102 103) are illustrated ready for connection to liquid lines that provide a liquid for chilling and remove a chilled liquid for use in a cooling application. Also illustrated are the enclosure height 510, depth 520 and width 530 along with front face 531, right face 534, and top face 535. Corresponding paired rear, left and bottom faces are provided. As desired, the liquid chiller enclosure may be at least partly supported by a ground surface on which the AC unit rests. Alternatively, it may be slightly elevated off the ground surface, such as by between 0.5 cm and 50 cm. FIG. 5 illustrates the enclosure that is adjacent to the split-system AC unit, so that both components may be positioned outside a building in an outdoor environment. Accordingly, liquid lines (not illustrated) connected to the enclosure liquid inlet and outlet run from the outside to the building inside. Ports and connections thereto can be positioned all on one face for ready access and connections in a manner that is not obstructed by the AC unit.
FIG. 6 illustrates one cooling application, where the liquid lines from the high efficiency liquid chiller system 10 are fluidically and/or thermally connected to a reservoir 600 containing cool liquid that functions as a cooling store, which, in turn, is used as desired. For example, the reservoir may have outlet cooling lines 620 to provide chilled liquid to a desired location remote from the reservoir, such as an indoor grow room having high intensity lights that generate a large amount of heat that must be dissipated. Any number of liquid-based air cooling devices may be used, to avoid unwanted heat build-up. The warmed liquid is then returned to the reservoir, such as by return line 630 in a closed-loop configuration. Referring to FIG. 6, liquid outlet line 448 is fluidically connected to pump 610 and, thereby, to liquid conduit in the chiller to provide a desired liquid flow-rate through the chiller heat exchanger and control of temperature in the reservoir 600. Other components useful for flow control are illustrated, including flow-meter, valves, and a strainer to avoid fouling or clogging of the heat exchanger in the chiller. In this manner, the high efficiency liquid chiller system 10 may be conveniently positioned outside a building, with the reservoir 600 positioned inside the building for on-demand cooling, independent of the status of chiller 10. In this manner, cooling is provided with the efficiency of the cooled liquid and related plumbing from and to the reservoir, without any need for bulky and intrusive ductwork.
Also provided herein are various methods of using or making the chillers described herein. FIG. 7 is a flowchart of a method of chilling a liquid with the disclosed system. The steps may include fluidically connecting an enclosed liquid chiller to an AC unit 700. The AC unit cools refrigerant 710 that is used for heat exchange with a liquid in an heat exchanger 720. The cooled liquid is removed from the liquid chiller 730 and used in a cooling application, such as for cooling or temperature control of a fluid reservoir 740, that can be used for on-demand cooling that is independent of the AC unit. As reflected in step 750, the heated refrigerant is removed from the enclosed liquid chiller and returned to the AC condenser unit 760 for subsequent cooling 710. Similarly, heated liquid from step 740 may be returned to the heat exchanger for subsequent cooling, as indicated by arrow 770. In this manner, the cooling temperature control can be in an entirely two-part closed-loop system: refrigerant and liquid.
FIG. 8 is a flow chart demonstrating a method of making any of the liquid chiller systems provided herein, by enclosing a liquid chiller within an enclosure 800 and providing liquid and outlet ports through the enclosure 810. Similarly, refrigerant inlet and outlet ports are provided through the enclosure 820. The refrigerant inlet and outlet ports are fluidically connected to the condenser unit of the AC unit in step 830. In this manner, the high efficiency liquid chiller system is ready for shipment and subsequent installation, such as in a configuration illustrated in FIG. 6.

STATEMENTS REGARDING INCORPORATION BY REFERENCE AND VARIATIONS

All references cited throughout this application, for example patent documents including issued or granted patents or equivalents; patent application publications; and non-patent literature documents or other source material; are hereby incorporated by reference herein in their entireties, as though individually incorporated by reference, to the extent each reference is at least partially not inconsistent with the disclosure in this application (for example, a reference that is partially inconsistent is incorporated by reference except for the partially inconsistent portion of the reference).
The terms and expressions which have been employed herein are used as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the invention claimed. Thus, it should be understood that although the present invention has been specifically disclosed by preferred embodiments, exemplary embodiments and optional features, modification and variation of the concepts herein disclosed may be resorted to by those skilled in the art, and that such modifications and variations are considered to be within the scope of this invention as defined by the appended claims. The specific embodiments provided herein are examples of useful embodiments of the present invention and it will be apparent to one skilled in the art that the present invention may be carried out using a large number of variations of the devices, device components, and method steps set forth in the present description. As will be obvious to one of skill in the art, methods and devices useful for the present methods can include a large number of optional composition and processing elements and steps.
When a Markush group or other grouping is used herein, all individual members of the group and all combinations and subcombinations possible of the group are intended to be individually included in the disclosure.
Every formulation or combination of components described or exemplified herein can be used to practice the invention, unless otherwise stated.
Whenever a range is given in the specification, for example, a number range, a pressure range, a fluid flow range, a quantity range, or any other range, all intermediate ranges and subranges, as well as all individual values included in the ranges given are intended to be included in the disclosure. It will be understood that any subranges or individual values in a range or subrange that are included in the description herein can be excluded from the claims herein.
All patents and publications mentioned in the specification are indicative of the levels of skill of those skilled in the art to which the invention pertains. References cited herein are incorporated by reference herein in their entirety to indicate the state of the art as of their publication or filing date and it is intended that this information can be employed herein, if needed, to exclude specific embodiments that are in the prior art.
As used herein, “comprising” is synonymous with “including,” “containing,” or “characterized by,” and is inclusive or open-ended and does not exclude additional, unrecited elements or method steps. As used herein, “consisting of” excludes any element, step, or ingredient not specified in the claim element. As used herein, “consisting essentially of” does not exclude materials or steps that do not materially affect the basic and novel characteristics of the claim. In each instance herein any of the terms “comprising”, “consisting essentially of” and “consisting of” may be replaced with either of the other two terms. The invention illustratively described herein suitably may be practiced in the absence of any element or elements, limitation or limitations which is not specifically disclosed herein.

Claims

I claim:

1. A high efficiency liquid chiller system comprising:

a split-system air conditioning unit comprising:

a condenser unit;

a condenser outlet thermally connected to said condenser unit for providing a source of chilled refrigerant from the condenser unit;

a condenser inlet thermally connected to said condenser unit for providing a source of refrigerant to be cooled by the condenser unit;

an enclosure having a chiller enclosure volume;

a liquid chiller positioned in the chiller enclosure volume, the liquid chiller comprising:

a refrigeration conduit comprising a refrigeration inlet and a refrigeration outlet;

a liquid conduit comprising a liquid inlet and a liquid outlet;

a heat exchanger that thermally connects the refrigeration conduit and the liquid conduit;

an inlet refrigeration line that fluidically connects the condenser outlet to said liquid chiller refrigeration inlet;

an outlet refrigeration line that fluidically connects the liquid chiller refrigeration outlet to the condenser inlet; and

wherein said inlet and outlet refrigeration lines are configured to position said enclosure adjacent to said split-system air conditioning unit with a separation distance that is less than or equal to 1 m.

2. The system of claim 1, wherein said separation distance is greater than or equal to 1 cm and less than or equal to 50 cm.

3. The system of claim 1, wherein an outer surface of said enclosure is in physical contact with an outer surface of said split-system air conditioning unit.

4. The system of claim 1, wherein said separation distance corresponds to a length of said inlet refrigeration line or said outlet refrigeration line.

5. The system of claim 4, wherein said inlet refrigeration line and said outlet refrigeration line have an independently defined lumen diameter that is greater than or equal to ¼″ and less than or equal to 1″.

6. The system of claim 1, wherein said inlet refrigeration line has a length less than or equal to 2 meters and said outlet refrigeration line has a length that is less than or equal to 2 meters.

7. The system of claim 1, wherein said enclosure is substantially rectangular-shaped having six faces defined by a length, a width and a depth, said six faces corresponding to:

opposibly facing top and bottom faces;

opposibly facing left and right side faces; and

opposibly facing front and rear faces.

8. The system of claim 7, wherein said enclosure is formed of a solid material with four access passages on one of the left or right side faces that provide fluidic access to said refrigeration conduit and said liquid conduit.

9. The system of claim 7, wherein said enclosure volume is less than or equal to 30,000 cm³.

10. The system of claim 9, wherein said liquid chiller provides a cooling capacity that is greater than or equal to 20,000 BTU/hr and less than or equal to 320,000 BTU/hr.

11. The system of claim 7, wherein the rear face of said enclosure opposibly faces an outer surface of the split-system air conditioning unit and is separated from the outer surface by the separation distance.

12. The system of claim 11, wherein said enclosure is formed of a solid material with four access passages on one of the left or right side faces that provide fluidic access to said refrigeration conduit and said liquid conduit so that said separation distance is less than a length of said inlet refrigeration line and less than a length of said outlet refrigeration line.

13. The system of claim 1, further comprising one or more of:

a liquid thermostat control connected to the liquid conduit to control temperature of liquid in the liquid conduit;

a temperature sensor connected to the liquid conduit or the refrigeration conduit for measuring temperature;

an expansion bypass valve connected between the refrigeration inlet conduit and the heat exchanger that fluidically connects to the refrigeration outlet conduit to bypass the heat exchanger;

a fan cycle switch operably connected to the refrigeration inlet conduit to cycle a condenser fan of an air conditioning compressor based on refrigerant pressure in the refrigeration inlet conduit;

a liquid flow switch operably connected to the liquid conduit to shut off an air conditioning compressor during a low liquid flow condition;

a refrigerant bypass line that fluidically connects the refrigeration inlet conduit and the refrigeration outlet conduit to fluidically bypass the heat exchanger;

a low pressure switch operably connected to the refrigeration conduit to stop flow during a low refrigerant pressure condition; or

a thermobulb and thermobulb capillary connected to an expansion bypass valve, wherein the thermobulb is fluidically connected to an exiting high pressure and high temperature refrigerant location and increases and decreases in temperature in response to increases and decreases in temperature of exiting refrigerant, to provide thermobulb expansion and contraction and an open or close condition of the expansion bypass valve, to compensate for an adverse temperature condition.

14. The system of claim 1, further comprising a refrigerant in said refrigeration conduit and a liquid in said liquid conduit, wherein said refrigerant comprises a blended hydrofluorocarbon mixture and said liquid comprises water or a mixture of water and anti-freeze.

15. The system of claim 1, further comprising an electrical system control, wherein said electrical system is electrically connected to said condenser unit.

16. The system of claim 1, further comprising a chilled-liquid reservoir fluidically or thermally connected to a chiller liquid conduit outlet.

17. The system of claim 16, said chilled-liquid reservoir having a volume that is less than or equal to 5 gallons per ton of cooling capacity.

18. The system of claim 16, further comprising a pump fluidically connected to the liquid conduit to provide a controlled fluid flow rate through the chiller heat exchanger.

19. The system of claim 18, having a liquid flow rate to the chiller that is greater than or equal to 2.3 GPM/ton of cooling capacity and less than or equal to 2.6 GPM/ton of cooling capacity.

20. The system of claim 19, further comprising a flow-meter fluidically connected to the liquid conduit to measure flow-rate of a liquid through the chiller.

21. A method of providing chilled liquid for a cooling application, the method comprising the steps of:

providing an enclosed liquid chiller that is fluidically connected to a split-system air conditioning unit, wherein the enclosed liquid chiller is separated from the split-system air conditioning unit by a separation distance that is less than or equal to 1 m;

cooling a refrigerant with a condenser unit of the split-system air conditioning unit to provide chilled refrigerant;

introducing the chilled refrigerant to a heat exchanger of the liquid chiller;

cooling a liquid in thermal contact with the heat exchanger with the introduced chilled refrigerant thereby generating cooled liquid and heated refrigerant;

removing heated refrigerant from the heat exchanger; and

introducing the heated refrigerant to the condenser unit;

thereby providing chilled liquid for a cooling application.

22. The method of claim 21, wherein the cooling application comprises an indoor agricultural facility further comprising the steps of:

thermally contacting the chilled liquid with a reservoir to provide a reservoir of cooled liquid for on-demand cooling of the indoor agricultural facility; and

returning warmed liquid from the thermally contacting step to the heat exchanger of the liquid chiller.

23. A method of making a high-efficiency liquid chiller comprising the steps of:

enclosing a liquid chiller within an enclosure;

providing a pair of inlet ports and a pair of outlet ports through said enclosure;

providing a refrigerant inlet and refrigerant outlet port through a surface of said enclosure;

fluidically connecting said refrigerant inlet and outlet ports to a condenser unit of a split-system air conditioning unit; and

wherein said enclosure has a volume that is less than or equal to 30,000 cm³and a separation distance from an outer surface of said split-system air conditioning unit that is less than or equal to 0.1 m.

24. The method of claim 23, wherein said fluidically connecting step comprises:

fluidically connecting an inlet refrigerant conduit to a condenser unit of the split-system air conditioning unit and to an inlet of a heat exchanger in the liquid chiller, wherein cooled refrigerant from the condenser unit is introduced via the inlet refrigerant conduit to the heat exchanger for cooling of the liquid in the heat exchanger; and

fluidically connecting an outlet refrigerant conduit to an outlet of the heat exchanger and to an inlet of the condenser unit for returning heated refrigerant from the heat exchanger to the condenser unit for cooling and subsequent introduction to the inlet refrigerant conduit.