WO2015131184A1

WO2015131184A1 - Freeze inhibiting regrigeration circuit and method of operation

Info

Publication number: WO2015131184A1
Application number: PCT/US2015/018295
Authority: WO
Inventors: Amir ABTAHI
Original assignee: Abtahi Amir
Priority date: 2014-02-28
Filing date: 2015-03-02
Publication date: 2015-09-03

Abstract

A system for inhibiting ice formation in a refrigeration circuit that includes having a compressor receiving and discharging a refrigerant, an evaporator coil with an inlet for receiving the refrigerant downstream of the compressor and an outlet for discharging the refrigerant, a condenser. The condenser, the compressor, and the evaporator coil are in liquid communication with one another through a refrigeration circuit. The system includes a hot-gas bypass circuit having an operational state with a first portion of the hot-gas bypass circuit receiving thermal energy from the refrigeration circuit at a location downstream of the compressor and upstream of the condenser and a second portion of the hot-gas bypass circuit thermally coupled to the evaporator coil without being in liquid communication with refrigeration circuit downstream of the condenser and upstream of the evaporator coil.

Description

FREEZE INHIBITING REGRIGERATION CIRCUIT AND METHOD OF OPERATION

CROSS-REFERENCE TO RELATED APPLICATION This application claims priority to U.S. Provisional Patent Application No. 61/946,297 filed February 28, 2014, titled "Freeze Inhibiting Evaporator and Method of Use," the entirety of which is incorporated by reference.

FIELD OF THE INVENTION

The present invention relates generally to a freeze inhibiting evaporator used in a refrigeration/heating circuit, and more particularly, relates to a freeze inhibiting evaporator used in water generation devices that harvest moisture from the atmosphere.

BACKGROUND OF THE INVENTION

Only 3% of the water present on Earth is drinking water, of which almost 1% is in the form of ice over the polar ice caps. One-point-two percent (1.2%) of drinking water is in the form of rivers, lakes, and ground water and the rest (0.8%) is present as atmospheric water vapor. This 0.8% translates to over 60 quadrillion liters of water that is replenished everyday by the hydrologic cycle. Due to the alarming increase of water pollutants and ever-growing requirement for clean drinking water, a need for a sustainable and dependable solution for clean drinking water is critical. One in every seven people across the globe does not have access to clean drinking water. Regions close to the equator and rural/remote areas often have no access to any water at all. Those regions fortunate enough to have one or more devices which manufacture or otherwise generate water are often inefficient and costly to operate and maintain. Furthermore, many of these known devices are commercially impracticable to move or transport to various locations. In many regions, the deprivation of clean water facilitates illnesses. As such, water-borne illness is the number one cause of infant mortality in these regions.

Atmospheric water generators operate like air conditioners with the major difference being that these machines are designed for maximum water generation rather than cooling air for conditioning purposes. A refrigerant is pumped through a coil with plurality of fins attached to augment the heat transfer area and thus the area available for cooling the air and subsequently condensing the moisture onto the fin surfaces. Good evaporator designs strive for an even temperature distribution, but fundamental laws of heat transfer dictate a cooler temperature at the coils than the fins. The refrigerant extracts the heat from the fins that in turn extract the heat from the air. As in all refrigeration cycles, the refrigerant heated and vaporized by all absorbed heat is drawn back to the inlet of a compressor which compresses the now gaseous refrigerant to a point where it reaches high temperatures and pressures. The superheated refrigerant is now cooled in another coil and fin apparatus called the condenser, where heat is rejected to the environment, and causing the refrigerant to condense and cool. The cycle is completed when the now high pressure cool refrigerant is essentially pushed through an expansion device where through the thermodynamic process of flash evaporation, it cools to very low temperatures useful in refrigeration or in this case water making.

It may seem that cooling the coils and the fins, thereby reducing the temperature of these surfaces, to below the dew point temperature of air, where water droplets form and condense out of moist air is a straightforward engineering task. However, achieving the dew point temperature and maintaining it with refrigerant temperatures that vary, air flow that may change based on a number of factors, and heat transfer characteristics that are highly sensitive to fin spacing, fin surface variations, and inherent variance in fabrication of components, make evaporator optimization a challenging task.

Water from air machines derive their basic technology from air conditioning machines. However, air conditioning machines are not as sensitive to these variations since a range of cooled air and a range of achieved humidity is acceptable. Achieving a proper surface temperature for water making machines is not as forgiving. If too much heat is removed by the refrigerant, or if the air velocity is too low, the coils and fins are sub-cooled and ice is formed, eventually blocking the air flow with the ultimate result of halting water generation. An insufficient rate of heat removal leads to warmer surface temperatures with virtually no water generation. While not necessarily limiting, most evaporators include a number of coils with fins that are spaced at 6 per inch, 8 per inch, 12 per inch, etc. While there are some evaporators with refrigerant flow control to achieve optimum temperatures through the evaporator, these devices are usually expensive to incorporate into water generation devices— that are generally produced to be at a lower cost— and do not always operate as designed or efficiently when used for water generation purposes.

For most evaporators, the flow of the refrigerant is set. As a result, the evaporator operates with a pre-set flow regardless of air temperature and humidity. The refrigerant flow settings are based on trial and error and it has been mostly determined by experienced engineers and technicians but not on any real-time dynamic feedback. Since water making machines are not as easy to operate and since a single "sweet spot" or optimized temperature/pressures setting cannot be determined for all operating conditions, many manufacturers have opted for rudimentary controls where ice is allowed to build up on the fins and then the refrigerant flow reduced or stopped to allow the ice to melt. This is a very poor operating procedure since ice is an insulator and essentially interrupts the heat transfer process. Therefore, it leads to an extremely inefficient method as it pertains to water generation.

Another well-known technique used in the air conditioning industry is the use of hot-gas bypass to reheat the air after it has gone through the cooling and dehumidification process in the coils. It is a simple procedure where some of the high-pressure and hot-compressed refrigerant that exits the compressor is routed to a heat exchanger right after the evaporator to raise the temperature of the air stream. The heat is essentially free since it would have been rejected to the environment, but now it serves a useful purpose. Some other known systems route and modulate the high-pressure and hot-compressed refrigerant directly from compressor into the piping or line leading into the evaporator when the system feedback reaches a pre-determined temperature. These systems, however, are prone to creating an unstable, and often uncontrollable, mixture that has detrimental effects not only on the components of the system, but also does not lend itself to the temperature control desired, and often required, by water generation devices. Further, it is believed that mixing hot refrigerant gas and cold refrigerant after the expansion valve, where flows with substantial pressure differences are mixed in a thermodynamically unstable zone, is not good engineering practice and could lead to premature refrigerant fatigue or separation between the many compounds that are mixed in modern refrigerants.

Therefore, a need exists to overcome the problems with the prior art as discussed above. SUMMARY OF THE INVENTION

The invention provides a freeze-inhibiting refrigeration circuit and method of operation that overcomes the hereinafore-mentioned disadvantages of the heretofore-known devices and methods of this general type and that effectively regulates the temperature of that of the coils and of the neighboring air surrounding the coils to inhibit sub-cooling.

With the foregoing and other objects in view, there is provided, in accordance with the invention, a system for inhibiting ice formation in a refrigeration circuit comprising that includes at least a compressor, an evaporator, a condenser, and a hot-gas bypass circuit. The compressor includes an inlet for receiving a refrigerant and an outlet for discharging the refrigerant. The evaporator includes an evaporator coil coupled and also includes an inlet for receiving the refrigerant downstream of the compressor and an outlet for discharging the refrigerant. The condenser, the compressor, and the evaporator are all in liquid communication with one another through a refrigeration circuit. Beneficially, the system also includes a hot-gas bypass circuit having an operational state with a first portion of the hot-gas bypass circuit receiving thermal energy from the refrigeration circuit at a location downstream of the compressor and upstream of the condenser and a second portion of the hot-gas bypass circuit thermally coupled to the evaporator coil without being in liquid communication with refrigeration circuit downstream of the condenser and upstream of the evaporator.

In accordance with a further feature of the present invention, the hot-gas bypass circuit is a closed system.

In accordance with another feature, an embodiment of the present invention includes a heat exchanger housing the first portion of the hot-gas bypass circuit and at least one hot-gas bypass valve in liquid communication with the first and second portions of the hot-gas bypass circuit. In accordance with yet another feature, an embodiment of the present invention includes at least one sensor disposed proximal to the evaporator coil or the fins of the evaporator, wherein the sensor is operably configured to detect a temperature of at least one of the evaporator coil and a fin associated with the evaporator. In accordance with an additional feature, an embodiment of the present invention includes an electronic control system communicatively coupled to either the sensor or the hot-gas bypass valv(e), or both. The electronic control system is operably configured to induce an open position of the hot-gas bypass valve(s) upon receiving the temperature of either the evaporator coil or the fin associated with the evaporator that is lower than or equal to a threshold temperature. The electronic control system is also operably configured to induce a closed position of the hot-gas bypass valve(s) upon receiving the temperature of either the evaporator coil or the fin associated with the evaporator that is greater than or equal to a threshold temperature.

In accordance with yet another feature, an embodiment of the present invention include a portion of a length of the bypass circuit that enters the evaporator, contours the evaporator coil, and exits the evaporator.

In accordance with another feature, an embodiment of the present invention includes the first portion of the hot-gas bypass circuit having an inlet in liquid communication with the refrigeration circuit at a location between the compressor and the condenser and an outlet in liquid communication with the refrigeration circuit at a second location of either (1) downstream of the evaporator and upstream of an expansion valve utilized in the refrigeration circuit or (2) at the hot-gas bypass circuit itself. The hot-gas bypass circuit defines a bypass circuit length that spans from the inlet of the hot-gas bypass circuit, through the evaporator, and to the outlet of the hot-gas bypass circuit. In accordance with another embodiment of the present invention, the system for inhibiting ice formation in a refrigeration circuit includes (1) a condenser, (2) a compressor in fluid communication with the condenser and operably configured to receive a refrigerant through a refrigeration circuit, (3) an evaporator having an inlet operable to receive the refrigerant from the condenser through a condenser line of the refrigeration circuit which has an evaporator coil disposed within the evaporator for transporting the refrigerant, and (4) a hot-gas bypass circuit with a first portion, a second portion housed in the evaporator, and having an operational state with the second portion of the hot-gas bypass circuit receiving thermal energy, from the refrigeration circuit downstream of the evaporator and upstream of the condenser, to a fluid medium transported within the hot-gas bypass circuit, wherein the fluid medium is transported to the second portion of the hot-gas bypass circuit without fluidly coupling with the condenser line of the refrigeration circuit.

Although the invention is illustrated and described herein as embodied in a freeze inhibiting refrigeration circuit, it is, nevertheless, not intended to be limited to the details shown because various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims. Additionally, well-known elements of exemplary embodiments of the invention will not be described in detail or will be omitted so as not to obscure the relevant details of the invention.

Other features that are considered as characteristic for the invention are set forth in the appended claims. As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which can be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one of ordinary skill in the art to variously employ the present invention in virtually any appropriately detailed structure. Further, the terms and phrases used herein are not intended to be limiting; but rather, to provide an understandable description of the invention. While the specification concludes with claims defining the features of the invention that are regarded as novel, it is believed that the invention will be better understood from a consideration of the following description in conjunction with the drawing figures, in which like reference numerals are carried forward. The figures of the drawings are not drawn to scale.

Before the present invention is disclosed and described, it is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. The terms "a" or "an," as used herein, are defined as one or more than one. The term "plurality," as used herein, is defined as two or more than two. The term "another," as used herein, is defined as at least a second or more. The terms "including" and/or "having," as used herein, are defined as comprising (i.e., open language). The term "coupled," as used herein, is defined as connected, although not necessarily directly, and not necessarily mechanically. The term "providing" is defined herein in its broadest sense, e.g., bringing/coming into physical existence, making available, and/or supplying to someone or something, in whole or in multiple parts at once or over a period of time.

As used herein, the terms "about" or "approximately" apply to all numeric values, whether or not explicitly indicated. These terms generally refer to a range of numbers that one of skill in the art would consider equivalent to the recited values (i.e., having the same function or result). In many instances these terms may include numbers that are rounded to the nearest significant figure. In this document, the term "longitudinal" should be understood to mean in a direction corresponding to an elongated direction of the evaporator. The terms "program," "software application," and the like as used herein, are defined as a sequence of instructions designed for execution on a computer system. A "program," "computer program," or "software application" may include a subroutine, a function, a procedure, an object method, an object implementation, an executable application, an applet, a servlet, a source code, an object code, a shared library/dynamic load library and/or other sequence of instructions designed for execution on a computer system.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying figures, where like reference numerals refer to identical or functionally similar elements throughout the separate views and which together with the detailed description below are incorporated in and form part of the specification, serve to further illustrate various embodiments and explain various principles and advantages all in accordance with the present invention.

FIG. 1 is a schematic diagram depicting an exemplary vapor compression refrigeration circuit utilizing a hot-gas bypass circuit in accordance with an embodiment of the present invention;

FIG. 2 is a fragmentary view of the evaporator utilized in the refrigeration circuit of FIG. 1 ; FIG. 3 is a schematic diagram depicting an exemplary vapor compression refrigeration system utilizing a hot-gas bypass circuit in accordance with another embodiment of the present invention; and

FIG. 4 is a process-flow diagram depicting a method for inhibiting the formation of ice in an evaporator used in a refrigeration circuit in accordance with the present invention. DETAILED DESCRIPTION

While the specification concludes with claims defining the features of the invention that are regarded as novel, it is believed that the invention will be better understood from a consideration of the following description in conjunction with the drawing figures, in which like reference numerals are carried forward. It is to be understood that the disclosed embodiments are merely exemplary of the invention, which can be embodied in various forms.

The invention described below, overcomes the disadvantages of those known systems described above, and currently available, as it may use a feedback control system that senses temperatures on the surface of the fins and/or coils of the evaporator, and uses a hot-gas bypass or reheat circuit to ensure that ice is not formed in the evaporator. This is achieved by a novel design of the evaporator incorporating the hot-gas bypass circuit therein. Referring now to FIG. 1, a schematic diagram depicting an exemplary refrigeration circuit 100 utilizing a hot-gas bypass circuit 102 are shown. Both the refrigeration circuit and the hot-gas bypass circuit 102 represent a system for inhibiting ice formation in a refrigeration circuit. FIG. 1 shows several advantageous features of the present invention, but, as will be described below, the invention can be provided in several shapes, sizes, combinations of features and components, and varying numbers and functions of the components.

The exemplary refrigeration circuit in FIG. 1 includes a compressor 104, a condenser 106, an expansion valve 108, and an evaporator 1 10. The term refrigeration circuit is defined as one or more pipes, conduits, or other means coupling one or more components to enable a refrigerant to be transported to generate a thermodynamic cycle. The refrigeration circuit 100 used in FIG. 1 may be a vapor refrigeration system, where the refrigerant is either vaporized or condensed. In other embodiments, the refrigeration system is a gas refrigeration system where the refrigerant substantially remains a gas throughout a thermodynamic cycle or another refrigeration cycle, e.g., absorption refrigeration. The invention utilizes a mechanical refrigeration system to condense moisture from atmosphere and an enclosure that houses the air filtration, mechanical refrigeration, water collection, air flow regulator, temperature/humidity monitoring, control, and other electrical systems. The term refrigeration circuit may also include configuring the components to run as a heat pump system.

The mechanical refrigeration system may include one or more means to compress the refrigerant, one or more valves to control the flow of the refrigerant, and heat exchanging surfaces to facilitate heat transfer from refrigerant to air and air to refrigerant. The air flow means regulates air flow over a specially designed heat exchanging surfaces, patterns and or varying fin arrangements to enhance the resident time of air over the heat exchange surface and also for more efficient moisture condensation.

The operation of the exemplary refrigeration circuit 100, in connection with hot-gas bypass circuit 102, includes the compressor 104 receiving a refrigerant, e.g., "Refrigerant 12," "Refrigerant 22," "Refrigerant 134a," through an inlet 1 12 which the compressor 104 then compresses, resulting in an increase in temperature and pressure of the refrigerant. The compressed refrigerant is then discharged through an outlet 1 14. The flow of refrigerant through the circuit 100 is reflected in the directional arrows depicted in FIG. 1. As depicted in the embodiment shown in FIG. 1, the refrigerant enters a heat exchanger 1 16 where the thermal energy of the refrigerant, at a temperature of approximately 120°F-140°F, is transferred to a first portion 1 18 of the hot-gas bypass circuit 102. The refrigerant is then discharged from the heat exchanger 1 16 and is then transferred to the condenser 106, where, as known to those of skill in the art, a flux of heat is dispelled out of refrigerant circuit 100 to an ambient environment. The refrigerant is then transported to an expansion valve, to the evaporator 1 10, and then back to the compressor 104, where the cycle repeats. Said differently, the compressor 104, condenser 106, expansion valve 108, and evaporator 1 10 are all in liquid communication with one another.

As discussed above, when the air is cooled proximate to the evaporator 1 10, e.g., fins, the moisture in the air condenses onto the fin surfaces and/or evaporator coil and, if cool enough, frees the condensed moisture into ice. The hot-gas bypass circuit 102 solves the above problem in an effective manner by, in its operational state, receiving the thermal energy from the circuit 100 downstream of the compressor 104, and preferably upstream of the condenser 106, and using this thermal energy to increase the temperature of those areas proximate to the evaporator 1 10, thereby reducing the possibility of the moisture freezing. The thermal energy is received by the first portion 118 of the circuit 102, wherein a fluid medium transported in the circuit 102 is heated up to temperature that is greater than the temperature of the temperature of the refrigerant entering the evaporator coil 122. Advantageously, a second portion 120 of the hot-gas bypass circuit 102 is thermally coupled to the evaporator coil 122, i.e., is able transfer a measurable amount of heat, without the second portion 120 being in liquid communication with refrigeration circuit 100 downstream of the condenser 106 and upstream of the evaporator 1 10. In some embodiments, the minimum rate of heat transfer, i.e., thermal conductivity, is approximately 0.02 - 400 (W/(m x k) @ ~ 25°C) (depending whether the transfer includes an air medium and/or copper piping) and may occur through one or more of the following methods of conduction, convection, or radiation. The rate of heat transfer at the second portion may be same or different than the rate of heat transfer at the first portion 1 18. The evaporator coil 122 can be seen having an inlet 126 for receiving the refrigerant downstream of the compressor 104 and an outlet 128 for discharging the refrigerant. The major difference between the methods of hot-gas reheat described herein, in comparison with other methods or schemes that are common in the air conditioning industry, is that the hot gas from the compressor 104 is not introduced in the refrigerant flow directly upstream of the evaporator 1 10; rather, the hot gas is transported to a coil 124 integral with the evaporator coil 122 with the purpose of improved temperature control and heat delivery modulation to water, should it be the fluid medium transported in the hot-gas bypass circuit 102. Another distinction is that, in the preferred embodiment, the thermal energy from the hot gas downstream of the compressor is fed or routed to a separate fin-coil assembly incorporated into the evaporator, that is usually called the "reheat coil".

The purpose of the method and system of the present invention is that the "hot-gas reheat" is quite distinct from the "hot-gas reheat" used in typical air conditioning units. The method described in this invention is to prevent freezing of the coils and/or fins which results in non- optimum water generation. The improved control eliminates the need for the rudimentary ON-OFF control of refrigerant flow that lowers the overall efficiency, and thus water generating capacity of atmospheric water generators.

As shown in FIG. 1, the hot-gas bypass circuit 102 is a closed system, or does directly and fluidly couple with the refrigerant cycle 100, as shown in FIG. 3. One method of reducing the temperature of the evaporator fins and/or coil 122 is transfer energy to the hot-gas bypass circuit 102 using the heat exchanger 1 16, which houses the first portion 1 18 of the circuit 102. The heat exchanger may utilize air as the heat transfer medium through the respective conduits of the circuits 100, 102. In other embodiments, the heat transfer medium may be water, copper, or another fluid or material, or combinations of fluids and/or materials. In one embodiment, the fluid medium transported within the hot-gas bypass circuit 102 is water. The water may also contain propylene glycol, or other antifreeze, that will circulate through the heat exchanger, which receives heat from the hot-gas coming from the compressor or from a source such as solar panels, other renewable sources or any available sources of heat. The use of hot water rather than hot gas will depend on the process and the optimum temperature requirements. For example, the hot gas from a compressor may be too hot and its introduction while maintaining proper temperature control difficult, while a lower temperature hot water circulated through the reheat coil may be easier to modulate. In other embodiments, the fluid medium may be the same refrigerant transported in the refrigeration circuit 100.

The hot-gas bypass circuit 102 may also utilize one or more hot-gas bypass valves 130, 132 and/or a pump 134 in liquid communication with the first and second portions 1 18, 120 of the hot-gas bypass circuit 102. The hot-gas bypass valves 130, 132 may be a ball valve, solenoid valve, check valve, knife valve, or other valve used to modulate the flow of the fluid medium. The system 100 may also use one or more sensors 136, 138 disposed proximal to the evaporator coil and/or evaporator fins (i.e., within the evaporator housing or within 6-7 inches of the evaporator housing or evaporator fins). The sensors 136, 138 are operably configured to detect a temperature of either the evaporator coil 122 and/or a fin associated with the evaporator.

The valves 130, 132, sensors 136, 138, pump 134, and/or condenser may advantageously be controlled by an electronic control system 140. The electronic control system 140 includes a microprocessor/controller communicatively coupled to the one or more temperature sensor(s) 136, 138 that are affixed to various locations on the coils 122 and/or fins of the evaporator 1 10. When the temperature of the fins is determined to induce icing, the microprocessor/controller actuates the valve(s) 130, 132 to open to transport the fluid medium, which is at a higher temperature than the coil 122 and/or fins, thereby inhibiting freezing of the same. Beneficially, the controller 140 will utilize a program, implemented by the microprocessor, to continually and/or intermittedly modulate the flow of fluid medium to the evaporator 1 10 upon receiving a temperature of either the evaporator coil 122 or the evaporator fin that is lower than or equal to a threshold temperature.

In one embodiment, the controller 140 induces an open position of the one or more hot-gas bypass valve(s) 130, 132 to enable the directional flow of the fluid medium. In other embodiments, the controller 140 also initiates the pump 134 to facilitate in the flow of the fluid medium. The controller 140 is also operable to induce a closed position of the valve(s) 130, 132, i.e., the flow to the evaporator 1 10 is interrupted, upon receiving a temperature of either the evaporator coil 122 or evaporator fin that is greater than or equal to a threshold temperature. In one embodiment, the threshold temperature is approximately 31°F-34°F, but in other embodiments, the threshold temperature may vary. In further embodiments of the present invention, the controller 140 may also be communicatively coupled to one or more components associated with the condenser 106 to modulate the rejection of heat energy stored in the refrigeration line 100. In one example, should the amount of thermal energy transferred to the hot-gas bypass circuit 102 in the heat exchanger 1 16 exceed a desired amount, the refrigeration circuit 100 may want to limit the amount of rejected heat energy by controlling the fan associated with the condenser 106. To determine the amount of thermal energy transferred to the hot-gas bypass circuit 102 in the heat exchanger 1 16, the controller 140 may also be communicatively coupled to one or more sensors, e.g., sensor 142, downstream of the heat exchanger 1 16.

With reference to FIG. 2, a fragmentary view of the exemplary evaporator 1 10 of FIG. 1 is shown. The evaporator 1 10 may include three coils inlets, 200, 202, 204, where one of the coils can be the "hot-gas reheat coil" 202. The determination of which coil is used for hot gas reheat will be based on environmental conditions, the machines characteristics, and refrigerant thermodynamic properties. The hot-gas reheat coil 208 can be of similar size or of a different size than the refrigerator coil(s) 122. In one embodiment, the hot-gas reheat coil 208 contours the evaporator coil(s) 122. Said differently, a portion of the bypass circuit length, which may vary from application-to-application, that enters the evaporator 1 10, contours the evaporator coil(s) 122 and exits the evaporator 1 10, as shown in FIG. 2, through an outlet 218 that may have one or more of coils outlets 210, 212, 214. The hot-gas reheat coil 208 can be a continuous coil or coils that connect two parallel headers on the two sides of the evaporator assembly 1 10. In one embodiment, the placement of the hot-gas reheat coil 208 may be intermediate of two refrigeration coil(s) 122 In other embodiments, the hot-gas reheat coil 208 may be in any other arrange and with less than or more than two refrigeration coil(s) 122. Once the hot-gas bypass valve(s) 130, 132 are opened in response to a controller 140, hot gas inherently flows to the lowest pressure point within the circuit(s) 100, 102, which may also be the at the lowest temperature where ice has build-up on the outside of the coil(s) 200, 204 if the hot gas from the refrigeration circuit is also used as the fluid medium (shown in FIG. 3). Therefore, the hot-gas bypass circuit 102, when used, prevents freezing and eliminates the need for intermittent flow of refrigerant which lowers the overall efficiency and thus water generating capacity of atmospheric water generators.

With reference now to FIGS. 2 and 3, the evaporator 1 10 can be seen having an inlet 206, that may include multiple coil inlets 200, 204 operable to receive the refrigerant from the condenser through a condenser line 308 of the refrigeration circuit 300. The refrigeration circuit 300 can be seen including an evaporator coil 122 disposed within the evaporator 1 10 for transporting the refrigerant. The evaporator coil 122 can also be seen with evaporator fins 216 coupled thereto, so as to provide a structure for the condensing moisture in the ambient air to accumulate on. FIG. 3 specifically represents another embodiment of the present invention that is shown without the use of a heat exchanger used in FIG. 1. In said embodiment, the refrigeration circuit 300 operates as discussed above, but the hot-gas bypass circuit 302 includes an inlet 304 in liquid communication with the refrigeration circuit 300 at a location between the compressor 104 and the condenser 106. The hot-gas bypass circuit 302 also includes an outlet 306 in liquid communication with the refrigeration circuit at a second location either downstream of the evaporator and upstream of the expansion valve 108 or at the hot-gas bypass circuit 302 itself.

As shown in FIG. 3, the outlet 306 is directly coupled into the line of the refrigeration circuit 302 downstream of the evaporator 1 10 and upstream of the compressor 104. In other embodiments, the hot-gas bypass circuit 302 may utilize a fluid medium separator that diverts fluid-medium vapor back to the outlet 306 upstream of the compressor 104 or fluid-medium vapor-liquid back to line downstream of the condenser 106 or upstream of the condenser 106 and downstream of the compressor 104. The hot-gas bypass circuit defines a bypass circuit length that spans from the inlet 304 of the hot-gas bypass circuit 302, through the evaporator 1 10, and to the outlet 306 of the hot-gas bypass circuit 302. Advantageously, the second portion of the hot-gas bypass circuit 302 thermally couples with the evaporator coil 208 without fluidly coupling with the condenser line 308 of the refrigeration circuit 300.

The above-described circuits 100, 102, 300, 302 may be incorporated into a portable water generation assembly used to generate water from an ambient environment. The assembly may include a supporting structure, a control panel that monitors/controls/regulates the system to regulate air flow mass within and through the device, an external control and internal sensors for monitoring and regulating system pressures and temperatures, an air filter or filters to filter particulates from incoming feed air, a baffle means to regulate air flow onto the condenser 106 sections, a bypass protection system for providing a means to safely disconnect or regulate the compressors 104 when operating under certain extreme working conditions, an insulation medium to insulate tubing in the circuits 100, 102, 300, 302 from heat losses, a lifting means to facilitate easy material handling of the assembly; a ducting means to regulate and direct air flow, and a series of control valves that offer means to measure and set system parameters.

With reference to FIG. 4, a process-flow diagram can be seen that depicts a method for inhibiting the formation of ice in an evaporator in a refrigeration circuit. The method immediately begins at step 400 and then moves to the step 402 of receiving a refrigerant, at a temperature Ti, at a compressor, wherein the compressor is part of a refrigeration circuit that includes an evaporator. This can be seen above in FIG. 1. The next step 404 includes compressing the refrigerant by the compressor to a compressed state. The compressed state of the refrigerant has a temperature T₂, wherein T₂ is greater than T . For example, going into the compressor the refrigerant may be in the form of a pure vapor and is at a temperature of approximately 60°F. Coming out of the compressor, however, the refrigerant is approximately 120°F-140°F.

Next, the process continues to the step 406 of transferring thermal energy to a fluid medium within a hot-gas bypass circuit as described above. Further, step 408 includes receiving the refrigerant, at a temperature T₃, at the evaporator through the refrigeration circuit. At the same time, before, or after the refrigerant has been received at the evaporator through the condenser line (discussed above), the next step 410 may include receiving a temperature from a sensor placed within the evaporator, e.g., the evaporator coil or the evaporator fin. After step 410, step 412 includes receiving the fluid medium, at a temperature T₄, at the evaporator through the hot-gas bypass circuit, wherein T₄ is greater than T₃. In certain embodiments, receiving the fluid medium, at the temperature T₄, occurs only when receiving the temperature T_¾ of the at least one of the evaporator coil and the evaporator fin that exceeds a threshold temperature. The process then ends at step 414.

The above-described process and assembly is only exemplary of the present invention and other components or features may be utilized in combination or in lieu of the above-described components/features, e.g., the utilization of components creating multistage or cascading vapor-compression systems. Further, the above-described steps may occur in varying positions of time.

The principal objectives of this invention are to provide an efficient and effective device for recovering atmospheric moisture; to provide such a device which is adapted for use in many geographic areas; to provide such a device which is portable; to provide such an apparatus which requires little maintenance or attention; to provide such an apparatus which does not pollute the environment; to provide such an apparatus which is relatively quiet in operation; and to provide such an apparatus which is economical to manufacture, efficient in use, capable of a long operating life, and particularly well adapted for the proposed use.

Claims

CLAIMS What is claimed is:

1. A system for inhibiting ice formation in a refrigeration circuit comprising: a compressor with an inlet for receiving a refrigerant and an outlet for discharging the refrigerant; an evaporator including an evaporator coil coupled thereto, the evaporator coil having an inlet for receiving the refrigerant downstream of the compressor and an outlet for discharging the refrigerant; a condenser, the condenser, the compressor, and the evaporator in liquid communication with one another through a refrigeration circuit; and a hot-gas bypass circuit having an operational state with a first portion of the hot-gas bypass circuit receiving thermal energy from the refrigeration circuit at a location downstream of the compressor and upstream of the condenser and a second portion of the hot-gas bypass circuit thermally coupled to the evaporator coil without being in liquid communication with refrigeration circuit downstream of the condenser and upstream of the evaporator.

2. The system according to claim 1, wherein: the hot-gas bypass circuit is a closed system.

3. The system according to claim 1, further comprising: a heat exchanger housing the first portion of the hot-gas bypass circuit.

4. The system according to claim 1, further comprising: at least one hot-gas bypass valve in liquid communication with the first and second portions of the hot-gas bypass circuit.

5. The system according to claim 4, further comprising: at least one sensor disposed proximal to the evaporator coil, the sensor operably configured to detect a temperature of at least one of the evaporator coil and a fin associated with the evaporator.

6. The system according to claim 5, further comprising: an electronic control system communicatively coupled to the at least one sensor and the at least one hot-gas bypass valve, the electronic control system operably configured to induce an open position of the at least one hot-gas bypass valve upon receiving the temperature of the at least one of the evaporator coil and the fin associated with the evaporator that is lower than or equal to a threshold temperature.

7. The system according to claim 6, wherein: the electronic control system is operably configured to induce a closed position of the at least one hot-gas bypass valve upon receiving the temperature of the at least one of the evaporator coil and the fin associated with the evaporator that is greater than or equal to a threshold temperature.

8. The system according to claim 1, wherein the hot-gas bypass circuit further comprises a portion of a length of the bypass circuit that the enters the evaporator, contours the evaporator coil, and exits the evaporator.

9. The system according to claim 1, wherein the first portion of the hot-gas bypass circuit further comprises: an inlet in liquid communication with the refrigeration circuit at a location between the compressor and the condenser; and an outlet in liquid communication with the refrigeration circuit at a second location at least one of downstream of the evaporator and upstream of an expansion valve utilized in the refrigeration circuit and at the hot-gas bypass circuit, the hot-gas bypass circuit defining a bypass circuit length that spans from the inlet of the hot-gas bypass circuit, through the evaporator, and to the outlet of the hot-gas bypass circuit.

10. A system for inhibiting ice formation in a refrigeration circuit comprising: a condenser; a compressor in fluid communication with the condenser and operably configured to receive a refrigerant through a refrigeration circuit; an evaporator having an inlet operable to receive the refrigerant from the condenser through a condenser line of the refrigeration circuit, the refrigeration circuit including an evaporator coil disposed within the evaporator for transporting the refrigerant; and a hot-gas bypass circuit with a first portion, a second portion housed in the evaporator, and having an operational state with the second portion of the hot-gas bypass circuit receiving thermal energy, from the refrigeration circuit downstream of the evaporator and upstream of the condenser, to a fluid medium transported within the hot-gas bypass circuit, the fluid medium being transported to the second portion of the hot-gas bypass circuit without fluidly coupling with the condenser line of the refrigeration circuit.

1 1. The system according to claim 10, wherein: the first portion of the hot-gas bypass circuit directly coupled to the refrigeration circuit at a position downstream of the compressor and upstream of the condenser.

12. The system according to claim 10, further comprising: a heat exchanger housing the first portion of the hot-gas bypass circuit.

13. The system according to claim 10, further comprising: at least one hot-gas bypass valve in liquid communication with the first and second portions of the hot-gas bypass circuit.

14. The system according to claim 13, further comprising: at least one sensor disposed proximal to the evaporator coil, the sensor operably configured to detect a temperature of at least one of the evaporator coil and a fin associated with the evaporator.

15. The system according to claim 14, further comprising: an electronic control system communicatively coupled to the at least one sensor and the at least one hot-gas bypass valve, the electronic control system operably configured to induce an open position of the at least one hot-gas bypass valve upon receiving the temperature of the at least one of the evaporator coil and the fin associated with the condenser that is lower than or equal to a threshold temperature.

16. The system according to claim 15, wherein: the electronic control system is operably configured to induce a closed position of the at least one hot-gas bypass valve upon receiving the temperature of the at least one of the evaporator coil and the fin associated with the condenser that is greater than or equal to a threshold temperature.

17. The system according to claim 10, wherein the hot-gas bypass circuit further comprises a portion of the hot-gas bypass circuit contours the evaporator coil.

18. A method for inhibiting the formation of ice in an evaporator in a refrigeration circuit, comprising the steps of: receiving a refrigerant, at a temperature T_1; at a compressor, the compressor being part of a refrigeration circuit that includes an evaporator; compressing the refrigerant by the compressor to a compressed state, the compressed state of the refrigerant having a temperature T₂, wherein T₂ is greater than transferring thermal energy to a fluid medium within a hot-gas bypass circuit; receiving the refrigerant, at a temperature T₃, at the evaporator through the refrigeration circuit; and receiving the fluid medium, at a temperature T₄, at the evaporator through the hot-gas bypass circuit, wherein T₄ is greater than T₃.

19. The method according to claim 18, further comprising: reducing a temperature T₅ of at least one an evaporator coil or an evaporator fin coupled to the evaporator through heat transfer from the hot-gas bypass circuit, wherein T₄ is greater than T_¾.

20. The method according to claim 19, further comprising: only receiving the fluid medium, at the temperature T₄, at the evaporator upon receipt of the temperature T_¾ of the at least one of the evaporator coil and the evaporator fin.