Patent Application
20170082327
This application claims the priority benefit under 35 U.S.C. 119(b) of Iraq Foreign Application No.: 320/2015, filed on Sep. 22, 2015, now granted Iraq Patent No. 4502, issued Mar. 3, 2016.
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1. Field of the Invention
The present invention relates to air-conditioners and refrigerators, methods of manufacturing same, and methods of using same. More particularly, the invention relates to solar-powered continuous cycle absorption air-conditioning and/or refrigeration systems.
2. Description of the Prior Art
Conventional prior art air-conditioners are well known in the art, including one of the most common types of refrigerant compressing air-conditioners that uses electricity and compressors. Besides the excessive electrical energy used by conventional air-conditioners, as well as the high cost of consumed electrical energy, compressors utilize refrigerant gases. Moreover, compressors produce annoying noise, creating other problems for neighbors and residents.
However, practitioners of those inventions have become aware of certain problems which are presented by those prior art inventions. One particular problem that has plagued users and sellers has been that the mechanisms of heating, ventilation, and air-conditioning HVAC systems utilize nearly one quarter of all the electricity generated in the United States for building comfort. In addition, in third world countries, where many villages and homes are off the grid, air-conditioning is relatively unavailable due to the cost and geographic unavailability for those residents.
During the 1950s and 1960s, the use of continuous cycle absorption refrigerating systems and propane-powered refrigerators was common. The continuous cycle absorption refrigerators were never used for air conditioners, just as refrigerators. These continuous cycle gas refrigerator systems most commonly used ammonia and water solutions in a generator. Most commonly, heat was applied to the ammonia solution by heating with electricity or by burning propane gas or kerosene. As the ammonia and water solution was heated to the boiling point of ammonia, the solution flowed into a separator. Ammonia gas solution would flow upward into a condenser, dissipating heat and converting the vaporized ammonia gas back into liquid.
The liquid ammonia would then make its way to an evaporator where it mixed with hydrogen gas and evaporated, producing cold temperatures in the refrigerator's freezer. Hydrogen gases, along with the ammonia, flowed to the absorber where the water collected in the separator mixed with the ammonia and hydrogen gases. Conventionally, then, the ammonia formed a solution with the water and released hydrogen gas, which flowed upwardly back into the evaporator. Once the hydrogen gas had been released, the remaining ammonia and water solution then flowed toward the generator to repeat the cycle. This continuous cycle absorption system remained air-tight so as not to release any ammonia into the atmosphere. Ammonia is well known to be a severe respiratory irritant, so the ammonia must stay contained.
Such a continuous cycle absorption refrigerator system has only been used for refrigeration and has never been utilized in the past for air-conditioning. It would be most advantageous to provide an air-conditioning and/or refrigerant system that uses very little or no electricity to provide air-conditioning and refrigeration and a method for manufacturing such an HVAC device.
As for conventional air conditioning systems, they have all been compressor-containing type systems that use large amounts of electricity. This is undesirable as mentioned above. Compressors use a refrigerant gas that has found great disfavor in the recent past, as they leak and contribute to green house gases. In many instances, the refrigerant gases used in these compressors have been outlawed for that reason.
Therefore, it would be desirable if there was provided a 2400 BTU or similar air conditioner/refrigeration device that used little or no electricity, and did not use a compressor for operation, along with a method of making it, and a method of using it.
In accordance with the above-noted desires of the industry, the present invention provides various aspects, including a solar-powered continuous cycle absorption air-conditioner and/or refrigerator system that competes favorably with conventional air conditioners and/or refrigerators that consume a lot of power. The present invention provides an unexpectedly good result for air conditioning and refrigeration by combining a conventional continuous cycle refrigeration unit with a solar thermal absorber that uses solar energy as its heat source to boil and evaporate an ammonia solution being used as the air conditioning or refrigerant fluid. Further in combination with such a refrigeration system and the solar thermal absorber is a sun tracking mechanical device with a linear Fresnel lens to maximize the sun's rays for optimum heating performance with such a conventional continuous cycle refrigerator system, along with a method of making same, and a method of using same.
One of the novel aspects of the present invention includes using an energy source of a solar energy absorbing surface on a heat generator made preferably of a metal heat collector, thereby replacing the heating source of a conventional continuous cycle refrigeration heat generator. Instead of burning kerosene or propane gas, as it would in a conventional continuous cycle refrigeration unit, the present invention utilizes a solar thermal heat collector in conjunction with some additional components to heat a refrigerator working fluid in a continuous cycle absorption refrigeration unit, thereby producing cold air. This overcomes many of the aforementioned problems with the prior art because the present invention uses an extremely low amount of electrical energy, if any is needed at all. Further, there are no compressors used in the present invention.
The most advantageous aspect of the present invention is that very little electricity is needed to operate the present invention, only about 0.25 Amps to about 1.0 Amps, for a fan to move the cold air. This advantage is due to the utilization of dry air by means of non-compressed refrigeration gas, requiring very little electricity. The only electricity required is merely for running a fan motor to blow the cool air into a room for air-conditioning or into a freezer for application as a refrigerator.
The present invention is divided into two parts, first, an outdoor unit containing a heat generator placed in a position for exposure to sunlight for heating. Second, there is an indoor unit housing the refrigeration components, a refrigerant fluid such as an ammonia solution, and a fan motor. A piping system connects the two parts so that the outdoor heat generator is exposed to sunlight where the ammonia solution is boiled, and then the boiled ammonia solution vapors are piped by natural convection into the indoor unit within the building or refrigerator freezer compartment. After processing, the condensed liquid ammonia solution flows downhill, back out to the heat generator for continuous cycling for re-boiling. This is a totally closed loop system so that ammonia does not leak out. No recharging of the ammonia is necessary.
Additional equipment is disclosed to help maximize the efficiency of the present invention. In particular, a Fresnel lens attached to a motorized sun tracking mechanism helps to optimize the air conditioning and/or refrigeration unit. Of particular interest is the use of a linear
Fresnel lens in order to help regulate the temperature of the heat generator. In addition, for cloudy days, when sunlight exposed to the heat generator may not be sufficient to reach the boiling temperature of the ammonia solution, a Fresnel lens may be used to capture more oblique light from the sunlight. To further increase the efficiency of the system of the present invention, a rotatable solar light collection tracker may be utilized.
A suitable sun tracker for directing the Fresnel lens into optimum positioning might include a motorized single or dual axis tracker. By mounting the sun tracker onto the frame of the Fresnel lens, the motorized tracker will follow the sun to position the Fresnel lens into optimum position.
Furthermore, as water condenses in the continuous cycle absorption system, the present invention can be used a source of distilled water for potable conditions. A water spout may emanate from the refrigerator.
Although the invention will be described by way of examples hereinbelow for specific aspects having certain features, it must also be realized that minor modifications that do not require undo experimentation on the part of the practitioner are covered within the scope and breadth of this invention. Additional advantages and other novel features of the present invention will be set forth in the description that follows and in particular will be apparent to those skilled in the art upon examination or may be learned within the practice of the invention. Therefore, the invention is capable of many other different aspects and its details are capable of modifications of various aspects which will be obvious to those of ordinary skill in the art all without departing from the spirit of the present invention. Accordingly, the rest of the description will be regarded as illustrative rather than restrictive.
For a further understanding of the nature and advantages of the expected scope and various aspects of the present invention, reference shall be made to the following detailed description, and when taken in conjunction with the accompanying drawings, in which like parts are given the same reference numerals, and wherein:
In accordance with the present invention, a new air-conditioning and/or refrigeration system is disclosed that utilizes solar energy for air conditioning or refrigeration by heating an ammonia-based refrigeration fluid in a continuous cycle absorption mode to generate cold air. Further, the disclosed invention does not use a compressor to generate cold, thereby eliminating the need for electricity to operate a compressor.
In its most basic form, the present invention creates cold air, and by its unique structure and methods of use, this cold air can either be used to provide chilled air blown into a room for air conditioned personal comfort, or the chilled air may be kept in a small compartment to act as a refrigerator or freezer for food storage, medical supplies, or any other typical use for a lower temperature environment.
Referring now to the drawings in detail,
These prior art absorption cooling units generally consist of four main parts: a boiler, a condenser, an evaporator and an absorber. Conventionally, this type refrigerator unit burns some type of fossil fuel, whether it be gas, kerosene or propane. The fuel is supplied to burners to heat refrigerant working fluids in the absorption cooling unit. Typically, the unit is charged with a refrigerant fluid of ammonia, water and hydrogen. The amount of ammonia is predetermined to be at a sufficient ammonia condensing pressure at or around room temperature. When heat is supplied to the system, the temperature of the ammonia solution rises, and boils to create ammonia solution gas which evaporates and rises through a pump.
Generally, the ammonia solution rises into the evaporator and the water separator. In the water separator, water vapor condenses and runs back down into the system, leaving the dry vapor ammonia in the condenser. As air circulates over the condenser plates, heat is removed from the ammonia vapors, condensing to a liquid ammonia. This liquid ammonia then enters the evaporator and hydrogen gas is introduced. Typically, the hydrogen gas arises from the surface of the ammonia, and the hydrogen gas lowers the partial pressure of ammonia vapors enough to persuade the ammonia to evaporate. When the ammonia evaporates, heat is extracted from the evaporator. In turn, heat is extracted from the space being cooled whether it is a refrigerator to store food or cold air being blown into a room to act as an air-conditioner.
Continuing on with the cycle, a mixture of ammonia, hydrogen, and vapors pass from the evaporator to the absorber. indoor this combined cycle, a continuous stream of the ammonia solution comes into the upper part of the absorber, as it is supplied by gravity. This ammonia solution flows through the absorber and comes in contact with the mixed ammonia and hydrogen gases. Hydrogen gas is free to ride through the absorber and is then returned to the evaporator. As one can see, hydrogen gas continuously circulates between the absorber and the evaporator, while a stronger solution of ammonia produced in the absorber flows into the absorber vessel. Thereafter, this newly formed stronger solution of ammonia produced in the absorber enters the boiler system to complete the full cycle of operation. This cycle runs continuously until the boiler is heated by the heat generator which controls a thermostat that governs the heat source and regulates the temperature of the refrigerated space.
As one who is familiar with such an ammonia refrigerant working fluid, it must be realized that extremely low temperatures are produced by the fluid. These low temperatures are transferred to make cold air by moving ambient air around Besides the thermostatic controls and fan motor (s) there are essentially no other moving parts.
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Condensed water from the operation of the system is essentially distilled water and may either be collected or discarded. A water spout from the bottom of the indoor unit (not shown) could easily be directed into a sterile container for potable water needs.
A suitable heat generator 42 is preferably a boiling tank made from steel or aluminum alloy of ammonia corrosion-resistant and high temperature resistant materials that exhibit a minimal Coefficient of Thermal Expansion. The metal should remain dimensionally stable from 100° C. to 600° C., depending on the required BTU capacity of the installation. The metal used to make the boiling tank should not be able to be corroded by the ammonia-based fluids that will be contained therein.
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However, as one can imagine, the sun does not always shine. In order to provide constant operation at night or on extremely cloudy days, an optional conventional burner 100 with a source of propane, kerosene or other fuels may be implemented. As one can imagine, heat generator 72 does not always receive full sunlight impinged onto its surface. In order to make this system more efficient, a Fresnel lens 90 may be used to concentrate available sunlight onto heat generator 72. In particular, in order to avoid spot heating, a linear Fresnel lens is found to be particularly useful, especially when it is directed toward the sun at an optimal angle by a motorized sun tracking system 94. Such a commercially available sun tracking system 94 would be optimally moved by a motorized mechanical means directed by a computer or a control panel 96. The control panel 96 is in electrical communication with the fan 84 and is programmed to synchronize between the indoor unit and the outdoor unit to the motor of the sun tracker 94.
In order to regulate the temperature needs of the comfort level for air conditioning in a room or for generating a suitable temperature freezer compartment, two thermostat sensors are most helpful. The first sensor 63 is located in the indoor unit in air filter 64 for sensing the incoming temperature of air, while the second sensor is an outdoor thermostat 43 within heat generator 42 to measure the temperature of the metal heat generator 42. The second sensor may be a thermocouple, providing information and signals back to the indoor thermostat 63. This information then regulates the fan 58 to either speed up to a High position or slow down to a Low position to achieve the desired temperature. Conventional thermocouples may be employed to measure temperatures and give appropriate signals.
Further, a sun tracking system 94, may be used to help locate and orient Fresnel lens 90 into a proper position for maximum sunlight capture onto heat generator 72. Sun tracker 94 may utilize a small amount of electricity to orient Fresnel lens 90 to concentrate the maximum amount of photons onto heat generator 72.
Although the present invention uses solar energy for solar absorption in the heat generator in the various aspects, this system still requires a small amount of electricity to operate the fan and the sensors, as well as the optional motorized sun tracker system. In order to provide this amount of electricity, the present system shall be in electrical communication with the local electrical grid or a sustainable battery pack sufficiently charged to provide enough electricity. In the event that a battery is used for off-the-grid locations, the battery may be charged by an auxiliary photovoltaic solar panel.
Now we review the solar energy source for operating the solar powered heat generator of the present invention. Heat generator 72 may be made of any suitable heat-collecting material, but is preferably made of a heavy metal, such as iron or steel for durability and heat capacity. While iron or steel will work without any further enhancements, such a metallic heat generator may be most preferably coated with a dark surface for collecting maximum amount of heat from the solar energy. A liner may be utilized to prevent the metal outer shell of the tank from coming into contact with the highly corrosive ammonia-based solution that the tank contains and heats. Preferable materials used for the heat generator include high thermal absorption and high heat capacity metals and/or stones, such as granite, and especially ones that are coated with heat absorbing coating materials. Although a stone heat generator may be fragile or brittle, once it is in place, one may find an advantage to using such a heat generator material. Appropriate metals may include iron of various sorts, steel, and/or other high heat capacity metals. In particular, coatings on the metal or stone heat generator substrates may be as simple as black paint or as complicated as plasmonic solar-absorbing coatings with high surface area upwardly extending whiskers.
A preferred type of thermal coating may be advantageously applied onto the sun facing surfaces of the heat generator tank. Such a thermal coating may include black paint coated on the heat generator acting as a solar collector absorber. Preferable coatings include a flat black thermal paint, tested with a near direct incidence of sun as well as with an azimuth angle of sunshine at about 45 degrees. A suitable thermal paint is preferably provided as a fully opaque coating of about 5 mm to 20 mm thick. A preferred paint is Rust-Oleum® flat black high temperature barbecue paint, commercially available from Rust-Oleum Company of Vernon Hills, Ill. in addition, another possible coating is Thurmalox® Solar Collective Coating 250 Selective Black, commercially available from Dampney Co., Inc. of Everett, Mass. Experimental results showed a consistently high temperature at the surface of a painted metallic heat generator of 155.4° F. (68.5° C.) with a paint thickness of about 10 mm, for near direct incidence of sun. In tests done at an azimuth angle of about 45°, the flat paint averaged a surface temperature of 153.6° F. (67.5° C.).
The ammonia solution best employed in various aspects of the invention is preferably a refrigerant grade anhydrous aqueous ammonia solution having from about 25% to about 35% by volume of anhydrous ammonia, balance of water, yielding an ammonium hydroxide solution. As the boiling point of a preferred 30% by volume ammonia solution is only 33° C. (91° F.), it is clear that vaporizing of the ammonia solution will occur when the temperature of the heat generator at direct sun incidence was 68.5° C., quite a bit higher than the boiling point of the ammonia solution. When the sunlight incidence was at an azimuth angle of about 45 degrees, a surface temperature of the heat generator was 67.5° C., which is sufficiently hot to make the present solar powered air-conditioning/refrigeration system operate.
The liquid lift piping 74 is preferably made of a metal type pipe with a coating of anti-corrosive thereon. Preferably, said piping 74 would be made of copper, galvanized steel or aluminum, and most preferably made of copper pipe.
Now we will review the other components of the present invention which add efficiency and provide the optimal amount of coolness to a desired location. Once again, the present invention uses solar energy to produce coolness, and that coolness can either be used to cool a room for personal comfort by being blown into the room by the fan. Or, in the alternative, the coolness may be kept in a freezer space and used to cool food or other items.
In order to achieve maximum efficiency for the present invention, an optional addition to the system may be a Fresnel lens, preferably mounted on a sun tracker system to constantly align the Fresnel lens in an optimum position with relation to the sun.
Generally, there are two types of Fresnel lens, as the main common types are either linear Fresnel lens or spot Fresnel lens. Spot lenses are probably ineffective for most applications with the present invention because they would concentrate too much sunlight onto one spot and superheat the ammonia solution. Spot lenses are capable of concentrating sunlight to achieve approximately 1500° F. at its focal point while a Linear lens is usually only capable of achieving approximately 200° F. at its focal point. On the other hand, a linear Fresnel lens would be able to regulate the necessary amount of sunlight to achieve a workable operating temperature. While a man can put his hand under a Linear lens exposed to sun light, and it may feel warm or hot, a Spot lens can burn flesh, start fires and might even melt steel used as the heat generator.
For the present invention, a Linear Fresnel lens is most advantageous, providing a workable system from about 2400 BTU up to 3600 BTU, thereby matching the capacity of continuous cycle absorption systems commercially available in the market. In contrast, it is possible to reach 6000 BTU using a continuous cycle absorption system with modifications to the size of the evaporator, the condenser, and the fan along with modifications to the size of the ventilation openings.
In practicing the present invention, a sun tracker may be advantageously mounted to the Fresnel lens to maximize efficiency, In accordance with the present invention, various commercially available solar tracking mechanisms may be modified to orient the Fresnel lens onto the heat generator without undue experimentation. The sun tracker will receive electronic signals to change its orientation throughout the day to follow the sun's path to maximize energy capture. Sun trackers help minimize the angle of incidence, ie. the angle that a ray of light makes with a line perpendicular to the surface of the Fresnel lens between the incoming light and the Fresnel lens, thereby increasing the amount of energy the installation produces. Sun trackers must be angled correctly to orient the Fresnel lens.
Single-axis solar trackers rotate on one axis moving back and forth in a single direction. Different types of single-axis trackers include horizontal, vertical, tilted, and polar aligned, which rotate as the names imply. Dual-axis trackers continually face the sun because they can move in two different directions. Types of suitable dual axis trackers may include tip-tilt or azimuth-altitude trackers. Dual-axis tracking may be advantageously used to orient the Fresnel lens and redirect sunlight along a fixed axis towards the stationary heat generator receiver. Because these dual axis trackers follow the sun vertically and horizontally, they help obtain maximum solar energy absorption.
There are also several methods of driving solar trackers. Passive trackers move from a compressed gas fluid driven to one side or the other. Motors and gear trains direct active solar trackers by means of a controller that responds to the sun's direction. Finally, a chronological type tracker can counteract the Earth's rotation by turning in the opposite direction.
The function of the indoor thermostat temperature sensor is to control the room temperature required by the user. The location of the thermostat sensor is in air filter of the Indoor unit, and is exposed to the hot air that comes from the ambient air in the room. Either of two types of sensors; manual and digital electronic thermostats may be utilized.
Air conditioning thermostats have either bi-metal units, as in older thermostats or thermistors, as found in newer thermostats. These thermostats sense the air current returning to the return ducts or the surrounding air.
For example, if the unit is in heat mode and the temperature is set at 70° F., the air conditioning thermostat senses the ambient room air currents and the air current temperature is 65° F. The heater will run until it picks up the ambient air current reading 70° F. at which time it will stop running. All HVAC thermostats work on this same principle. Regardless if it is a digital thermostat, programmable, talking thermostat, telephone thermostats or zoning thermostat, it will rely on the ambient air temperature to work.
The outdoor thermostat temperature sensor has the same function as the indoor thermostat temperature sensor. This type is always used in electrical heaters.
Location of the outdoor thermostat temperature sensor is at the body of the generator metal outdoors. The function of the outdoor thermostat temperature sensor is that it controls the temperature of the metal body of the heat generator. The amount of sunlight that impinges on the heat generator metal might be very high, so much so that it might melt the metal. The melting point of the metal used for the generator metal is already known from the specification of its physical properties.
In contrast, if the air conditioning unit is turned on, the electronic control board-programmed panel will check to see whether the generator is hot enough or not for operation. If it is not hot enough, then it sends an electronic signal to order the sun-tracker to search for sunlight, and if it is hot enough to operate the A/C then the fan will operate. The fan regulator can be switched on to automatic mode or manual mode. The automatic mode let the electronic control board-programmed panel give the correct level of the regulator with the required room temperature.
The function of the electronic control board-programmed panel is to synchronize all the following parts together: Indoor Thermostat Temperature Sensor, Out-door Thermostat Temperature Sensor, Fan and the electrical motor of the sun tracker. After receiving digital read-outs of the indoor and the outdoor sensors, signals are sent to the fam and the electrical motor of the sun tracker.
In a room of length 4 meters, width 3 meters, and height of 3 meters, a 2400 BTU solar powered continuous cycle absorption system was operated with a full sunny day, and the shed temperature is 30° C. The required BTU is about 2400. A fan-less Sun Frost propane refrigerator, with a consumption rate normally of 1.5 pounds or 0.375 gallons/day of propane is modified to add a fan out of the freezer space and longer pipes to move an ammonia-based solution in and out of the Sun Frost refrigerator between the refrigerator inside the room and a heat generator boiling tank out-of-doors and set out in the sun. After about 20 minutes, the boiling tank was hot enough to boil the ammonia-based solution. The newly added fan blew cold air out into the room and was able to compare favorably with a 2400 BTU conventional air conditioner.
In summary, numerous benefits have been described which result from employing any or all of the concepts and the features of the various specific aspects of the present invention, or those that are within the scope of the invention. The solar powered air conditioner or refrigerator acts as a low energy requiring, non-compressor using system particularly useful for sunny climates.
The foregoing description of a preferred aspect of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Obvious modifications or variations are possible in light of the above teachings with regards to the specific aspects. The aspect was chosen and described in order to best illustrate the principles of the invention and its practical applications to thereby enable one of ordinary skill in the art to best utilize the invention in various aspects and with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims which are appended hereto.
| Number | Date | Country | Kind |
|---|---|---|---|
| 320/2015 | Sep 2015 | IQ | national |
