Not applicable.
The present invention relates generally to production of water, and more specifically to improved systems and methods for extracting water from water vapor, for example from the atmosphere.
Ambient air naturally contains some quantity of water vapor, so the general atmosphere is a potential water source. Extracting this water from the surrounding atmosphere presents several challenges. Other attempts to produce water from atmospheric air have typically fallen short of the desirable criteria, including efficiency in the amount of water produced per the amount of energy used, extracting the greatest possible percent of the moisture available in the air under local conditions, and producing acceptable quantities of water at all times of day and in various weather, seasons, and climates. Therefore, atmospheric water vapor is an essentially untapped source of greatly needed water supplies that is potentially available worldwide.
Refrigeration systems have been known for some time. Vapor-compression cycle refrigeration systems are most common today, but other types of refrigeration are possible including gas absorption and heat pumps. If the refrigeration system uses a vapor compression cycle, it may include a compressor, evaporator, expansion valve, and condenser. Diagrams of an example vapor compression refrigeration system, and its thermodynamic operation, are shown in
Most refrigeration systems have some cooling element, through which air passes to shed heat and reach a lower temperature. In a vapor compression cycle refrigeration system, the cooling surface of the cooling element will be an exterior surface of the evaporator. An evaporator having a temperature of at most a dew point of air contacting the evaporator will cause liquid water to condense on an exterior surface of the evaporator.
Whenever this cooling element has a temperature at or less than the local dew point of the air, water vapor in the air will tend to condense into droplets of liquid water. When a cooling element has a temperature at or less than the freezing point of water, such as in a freezer, water vapor in the air will tend to condense and then freeze into ice.
In most residential and commercial refrigeration systems, this condensation is considered undesirable, and some refrigeration systems even have features for ameliorating them. However, the principles causing such condensation can be used to produce liquid water from water vapor in atmospheric air.
Exemplary methods of water production and accompanying apparatus are described in U.S. Pat. No. 6,343,479, entitled “Potable Water Collection Apparatus” which issued on Feb. 5, 2002, and U.S. Pat. No. 7,121,101, entitled “Multipurpose Adiabatic Potable Water Production Apparatus And Method” which issued on Oct. 17, 2006, the entire contents of both of which are incorporated by reference.
These patented methods and devices present viable means of extracting liquid water from atmospheric air, including apparatus for transforming atmospheric water vapor into potable water, and particularly for obtaining drinking quality water through the formation of condensed water vapor on surfaces maintained at a temperature at or below the dew point for a given ambient condition. The surfaces upon which the water vapor is condensed are kept below the dew point by a refrigerant medium circulating through a closed fluid path, which includes refrigerant evaporation apparatus, thereby providing cooling of air flowing through the device, and refrigerant condensing apparatus to complete the refrigeration cycle.
It is desirable to be able to control the amount of and temperature of the air passing over the evaporator to provide efficient and economical water production during conditions when the ambient wet bulb and dry bulb temperatures indicate high relative humidity or less than ideal atmospheric conditions.
The present invention advantageously provides a system, device and method for extracting water from air. A water production system may include an air duct, an air movement device, and a refrigeration system. The air duct may have an entry port, an intermediate port, and an exit port. The air movement device may be a fan inside the air duct. The refrigeration system may include a cooling element such as for example an evaporator as well as a condenser within the air duct, with the evaporator maintaining a temperature at the dew point or less, to cause liquid water to condense on the evaporator.
The air duct defines a first air flow path sequentially through the entry port, evaporator, condenser, and exit port. And the air duct also defines a second air flow path sequentially through the intermediate port, condenser, and exit port. This second air flow path bypasses the evaporator.
In some embodiments of the present invention, the intermediate port may remain open, or may be fitted with a bypass valve to control the bypass air flow. If a bypass valve is provided, it may be binary (open or closed) or fully adjustable to a variety of positions between and including open or closed. A bypass valve may be manually operated or have an automatic controller, which may operate the bypass valve according to certain conditions including the air temperature and humidity. A controller may for example be programmed to open the bypass valve when the air exceeds a selected temperature, and to close the bypass valve when the air falls below that temperature.
In other embodiments of the present invention, the air duct may also have at least one additional intermediate port, such that the intermediate port may provide a conditional air bypass, and the additional intermediate port may provide a persistent air bypass.
The elements of a water production system according to the present invention may be selected from among many different suitable materials having the desired physical properties. Some of these characteristics may include for example strength, thermal insulation or transmission, corrosion resistance, and material performance in a broad range of temperatures and pressures. Acceptable materials may include metals such as for example copper, aluminum, steel, stainless steel, as well as polymers.
Of course, a water collection vessel may be positioned proximate, e.g., under, the evaporator to collect liquid water.
In accordance with another aspect the present invention provides a method of using a water production system to extract water from air. The water production system includes a refrigeration system having a cooling element and an air duct having an entry port, an intermediate port, and an exit port in which the air movement device is operated to cause air to flow along a first flow path into the entry port, through the cooling element, and out the exit port, and along a second flow path into the intermediate port, and out the exit port, thus bypassing the cooling element. The refrigeration system is operated to cause the cooling element to maintain a temperature of at most a dew point of air contacting the cooling element. Liquid water is condensed on an exterior surface of the cooling element and the liquid water is collected.
A more complete understanding of the present invention, and its associated advantages and features, will be more readily understood by reference to the following description and claims, when considered in conjunction with the accompanying drawings.
A more complete understanding of the present invention, and the attendant advantages and features thereof, will be more readily understood by reference to the following detailed description when considered in conjunction with the accompanying drawings wherein:
The present invention advantageously provides an improved system and method for extracting water from water vapor, for example from the atmosphere. The water production system of the present invention may have various sizes, arrangements and features.
Some aspects of the present invention relate to combinations of components and method steps for implementing systems and methods to improve the efficiency and operation of water production systems. Accordingly, some components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present invention, so as to avoid details that will be readily apparent to those of ordinary skill in the art having the benefit of this description.
Relational terms, such as “first” and “second,” “top” and “bottom,” and the like, may be used solely to distinguish one entity or element from another entity or element, without necessarily requiring or implying any physical or logical relationship or order between such entities or elements.
Referring to the drawings, various embodiments of water production devices are illustrated. The illustrations of course depict only some of many different possible designs that are within the scope of the present invention. In particular, the present invention encompasses water production systems having numerous combinations of elements, and the description of any element also contemplates providing more than one of that element. For clarity and convenience, the present detailed description will only describe a few specific embodiments of the present invention.
An apparatus for extracting water from the water vapor in atmospheric air may generally include an air duct, a refrigeration system, and an air movement device. The air duct may have one or more ports, including an entry port and an exit port. The air movement device may be a fan disposed within the air duct, operable to draw air through the air duct.
In some embodiments of the present invention, an intermediate port may be provided between the entry port and exit port, such that the air duct defines a first and second air flow path. The first air flow path may proceed sequentially through the entry port, evaporator, condenser, and exit port. In contrast, the second air flow path may proceed sequentially through the intermediate port, condenser, and exit port, thus bypassing the evaporator. In other words, with the intermediate port being positioned between the evaporator and condenser, air can enter the air duct: (i) through the entry port and evaporator, and (ii) through the intermediate port, bypassing the evaporator. The air movement device in such embodiments is capable of moving air through the air duct along the first and second air flow paths.
The refrigeration system may be of various types, including vapor compression cycles, gas absorption and heat pumps. Regardless of which type of refrigeration system is chosen, the refrigeration system should have at least one cooling element, with an exterior cooling surface. During operation, the cooling surface is maintained at a temperature which is at or less than a dew point of air. In other words, atmospheric air flowing through a water production system can contact a cooling element of a refrigeration system having a temperature of at most the dew point, to cause liquid water to condense on a cooling surface.
With specific reference to the drawings, in which like reference designators refer to like elements, an exemplary embodiment of a water production system according to the present invention is shown in
As is shown in
The refrigeration systems 14a and 14b (referred to collectively herein as “refrigeration system 14”) of the present invention may also have various arrangements of refrigeration components, including for example compressors 24a and 24b (referred to collectively herein as “compressor 24”), evaporators 28a-d (referred to collectively herein as “evaporators 28”), expansion valves 26a-d (referred to collectively herein as “expansion valves 26”), and condensers 30a-d (referred to collectively herein as “condensers 30”). An evaporator 28 and a condenser 30 may both be positioned within an air duct 12 of the present invention. The refrigeration system may provide one or more closed circuits for a refrigerant medium. For example, a refrigeration circuit may be arranged from a compressor, to a condenser, to an expansion valve, to an evaporator, and back to the compressor.
The particular embodiment of a water production system shown in
Water production systems according to the present invention may have one or more bypass ports that remain open, or may be selectively opened and closed, either in a binary or selectively adjustable fashion. For example, water production system 10 may be provided with intermediate ports 20 defined on the top of the water production system between each pair of evaporators 28 and condensers 30, and additional intermediate ports 32a and 32b (referred to collectively herein as “intermediate ports 32”) defined on both sides of each pair of evaporators 28 and condensers 30.
Accordingly, in the present embodiment there are: (i) four sets of first flow paths, each of which begins with an entry port 18, proceeds through an evaporator 28, then a condenser 30, and out the exit port 22; and (ii) four sets of second flow paths, each of which begins with intermediate ports 20 and 32, proceeds through a condenser 30, and out the exit port 22, thus bypassing the evaporators.
The operating temperature of the evaporator depends upon the pressure of the refrigerant flowing through it. This refrigerant pressure is affected, in turn, by the volume of air flowing through the evaporator. By passing a portion of air flowing through the air duct directly to the condenser without passing through the evaporator, refrigerant pressure in the evaporator is lowered, and the operating temperature of the evaporator is lowered, thereby improving the efficiency of the system to produce water.
Differing types of intermediate ports are possible. For example, intermediate ports may have a variety of shapes, including square, rectangular, polygonal, rounded, circular, and even irregular shapes. Likewise, intermediate ports may have any suitable arrangement, positioning, number, or layout. A singular intermediate port may suffice, or a series of smaller intermediate ports may be used.
Bypass ports may also be controllable, with bypass valves that may be opened or closed, or may be selectively adjusted to numerous discrete partially-open positions, or may be manipulated continuously to any arbitrary position inclusively between an open or closed position. If more than one intermediate port is provided or more than one bypass valve is provided, then they may all be collectively adjusted or movable as a group, or individually, or in any desired combination or arrangement.
Again, differing types and shapes of bypass valves are possible. For example, bypass valves may be planar, louvered, an iris diaphragm, or any other suitable shape. Bypass valves may also move in different ways, including for example rotating, sliding, hinged turning, expansion and contraction. Moreover, the elements of a bypass valve 34 may have various physical characteristics, including flexible, inflexible, and resilient.
In particular, a bypass valve 34a-d (referred to collectively herein as “bypass valves 32”) may be affixed to intermediate ports 20, selectively operable between open and closed positions. Bypass valves 34 may also be selectively operable to a plurality of partially open positions between the open and closed positions. Bypass valves may be manually operable or automatic, programmed to change positions in response to any suitable condition(s), including at selected times, temperatures, humidity, geographic location, the presence or absence of sunlight or other weather conditions, etc. In addition, although the drawing figures show four bypass valves 34, fewer or greater than four can be implemented as needed. It is also contemplated that the bypass valves 34 can be operated, i.e., opened/closed, together or each individual bypass valve 34 can be separately controlled.
As is shown in
The controller 36 may have any configuration suitable for controlling one or more bypass valves as desired, including for example electromechanical timers and apparatus for manipulating valve components, or computer or CPU-based systems that are programmable to adjust bypass valve(s) according to a variety of inputs and conditions. Different sensors or input devices may be used to guide the controller, including for example a clock, timer, thermometer, humidity sensor, rain sensor, light sensor, etc.
In differing conditions, whether for example atmospheric, climate, time, humidity, or daylight, a different component or subsystem of a refrigeration system may reach its capacity. For example, at high temperatures and high humidity, operation of the refrigeration system may be limited by the capacity of an evaporator, so it may be desirable to allow some or more air flow to bypass that evaporator. Conversely for example, at lower temperatures, operation of the refrigeration system will tend not to exceed the capacity of an evaporator, so it may be desirable to lessen the bypass air flow.
Accordingly, the bypass valves may be closed at lower temperatures, thereby allowing more air to flow over the evaporator. At higher temperatures, the bypass valves may be opened, thereby allowing more air over the condenser in comparison to the amount of air flowing over the evaporator. Less air over the evaporator will tend to lower the refrigerant temperature in the evaporator.
In one embodiment, the bypass valve position may be controlled by a stepper motor. A specific example water production system may operate with the bypass valves closed, for example at approximately 10 pounds of air per minute. With the bypass valves open, the air pressure capacity may drop to about 8 pounds per minute, thereby requiring less energy to operate. With larger bypass ports, the air pressure capacity may be able to be lowered to approximately 5 pounds per minute.
The additional intermediate ports 32 may remain open and provide a persistent air bypass, in that air flowing into additional intermediate ports 32 bypasses the evaporators 28. In contrast, adjustable intermediate ports 20 may provide a conditional air bypass. Depending on the condition of the bypass valves 34, whether they are open, partially open, or closed, air may flow into intermediate ports 20 and bypass the evaporators 28 to a greater or lesser extent.
While conventional refrigeration systems may be optimized for cooling the air in a chamber, water production systems are optimized for production of water. Accordingly, bypass ports may be desirable because otherwise a water production system such as system 10 will tend to exceed the air flow capacity of the evaporators. If desired for improved efficiency and operation, the water production system may be optimized by selecting condensers with a greater capacity for air flow than the evaporators.
In embodiments having more than one evaporator and condenser, it may also be desirable to connect the evaporators to the refrigeration system in parallel, and yet connect the condensers to the refrigeration system in series. In this case, the refrigeration system may be arranged to cause the refrigerant to exit the first condenser in a gaseous state, and to exit the second condenser in a liquid state, such that the first condenser acts as a de-superheater.
Water production systems of the present invention may also be provided with an ice sensor 38 capable of sensing ice buildup on an evaporator 28, and a switch 40 coupled with the ice sensor 38 to shut off the refrigeration system 14 when ice is present, with the air movement device 16 remaining in operation.
With specific reference to
Another embodiment of the present invention may provide one or more additional refrigeration systems. For example, the illustrated embodiment includes an additional compressor and expansion valve. The first and second refrigeration systems define separate closed-loop refrigerant paths, and each refrigeration system is arranged in a similar fashion.
Of course, one or more water collection vessels or containers 42 may be positioned near the evaporators 28 for collecting the liquid water. If desired, these containers 42 may be further coupled to additional water treatment apparatus, or filtration systems, etc.
In operation of the water production systems of the present invention, a method of extracting water from air may include, for example, providing an air duct having an entry port, an intermediate port, and an exit port; providing an air movement device; and providing a refrigeration system including a cooling element. The method may also include operating the air movement device to cause air to flow along a first and second air flow path. The first flow path may be into the entry port, through the cooling element, and out the exit port, while the second flow path may be into the intermediate port, and out the exit port, thus bypassing the cooling element. The method according to the present invention may further include operating the refrigeration system to cause the cooling element to maintain a temperature of at most a dew point of air contacting the cooling element. The present invention may also include condensing liquid water on an exterior surface of the cooling element, and collecting the liquid water.
In the method of the present invention, a bypass valve may further be provided, and may also include determining a temperature of the air, opening the bypass valve when the temperature exceeds a selected temperature, and closing the bypass valve when the temperature falls below the selected temperature. The method of the present invention may also include adjusting one or more bypass valves in response to a variety of conditions, inputs or sensors, including for example a thermometer, clock, timer, humidity sensor, rain sensor, light sensor, etc.
The method of the present invention may also include, when the air duct further has an additional intermediate port and a bypass valve capable of opening and closing the intermediate port, maintaining the additional intermediate port open during operation of the water production system.
In a specific example embodiment of the present invention, a water production system may be provided as shown in the drawings, with various components being selected as follows: two matching refrigeration systems, each having a 5 hp compressor, a pair of evaporators with an air flow capacity of 100 pounds of air per minute, an expansion valve, and a pair of condensers with an air flow capacity of 200 pounds of air per minute. The fan was selected having a capacity of 200 pounds of air per minute, and adjustable bypass valves were provided with a controller set to open them above an ambient air temperature selected at 78 degrees Fahrenheit, or 25.6 degrees Celsius. The resulting example embodiment produced approximately 0.5 liters of water per minute.
With specific reference to
Several advantages may be achieved with the present invention, including for example enhanced efficiency, lowering the amount of energy used to produce a specific amount of water when operating the water production system. Another advantage of the present invention includes broadening the possible environments, geographical areas, weather conditions, and times of day when the water production system of the present invention may be used effectively and efficiently. Moreover, the present invention may provide the advantage of balancing the respective capacities of the various refrigeration system components, such as for example the capacity of one or more evaporators and condensers.
It should be understood that an unlimited number of configurations for the present invention could be realized. The foregoing discussion describes merely exemplary embodiments illustrating the principles of the present invention, the scope of which is recited in the following claims. In addition, unless otherwise stated, all of the accompanying drawings are not to scale. Those skilled in the art will readily recognize from the description, claims, and drawings that numerous changes and modifications can be made without departing from the spirit and scope of the invention.
This application claims priority to U.S. Provisional Application Ser. No. 61/102,120, entitled “Methods and Systems for Potable Water Production,” filed Oct. 2, 2008, and to U.S. Provisional Application Ser. No. 61/184,956, entitled “Method And System For Water Recovery From Air Using Combined Receiver And Water Cooled Condenser,” filed Jun. 8, 2009, the entirety of both of which are incorporated herein by reference.
Number | Date | Country | |
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61102120 | Oct 2008 | US | |
61184956 | Jun 2009 | US |