Solar Powered Heating and Air Conditioning
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A solar powered system for providing heat, power and air condition. According to at least one aspect of the invention, there is described a system for using solar power and solar heat to heat a liquid that can be used to control heat, power, cooling, and humidity in a structure to provide an autonomous building that is independent of power grids. The solar system can utilize a desiccant cycle to cool liquid which can be used for air conditioning. An advanced recycling system can use water in stages (i.e., “gray water”) to efficiently use and recycle scarce water with a limited amount of power requirements.

De Lima, Daniel D. (Norfolk, VA, US)
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1. A solar powered air conditioner having a vapor liquid separator and using a desiccant and a gray water cycle.



This application is a continuation-in part of U.S. patent application Ser. No. 11/948,029, filed Nov. 30, 2007, which is incorporated herein by reference. This application claims the benefit of U.S. Provisional Application 61/021,356, filed Jan. 16, 2008, which is also incorporated herein by reference.


1. Field of the Invention

The present invention relates to a method and apparatus for using solar power to heat, power and cool a structure.

2. Description of the Prior Art

Interest in solar power continues to accelerate in the face of global warming, concern over the long term availability of petroleum and the pressures of rising energy prices. Tapping even a portion of available solar power has the potential to reduce reliance on petroleum and to hopefully reduce pressures on the national energy grid by distributing power generating sources more locally. Additionally, using solar power in remote locations decreases the reliance on power grids and reduces the costs associated with extending copper wire long distances to service sparsely populated areas. Having a standalone, modular system that can be added to or incorporated into a structure to provide a self sufficient building that can be located independent of power grids.

One drawback to solar power, however, is that it tends to have low thermal efficiencies and the amount of area that a home would need to break even for the year on energy requirements is very high. What is needed is a way to make the most of the solar energy available to power a home while maximizing its efficiency by taking advantage of heated water or other fluids instead of converting solar to electricity and then to heat.

None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.


According to at least one aspect of the invention, there is described a system for using solar power and solar heat to heat a liquid that can be used to control heat, power, cooling, and humidity in a structure to provide an autonomous building that is independent of power grids. The solar system can utilize a desiccant cycle to cool liquid which can be used for air conditioning. An advanced recycling system can use water in stages (i.e., “gray water”) to efficiently use and recycle scarce water with a limited amount of power requirements.

It is therefore an object of one aspect of the invention to provide a HVAC system that runs on solar power that provides heat, air conditioning and electricity.

It is another object of an embodiment of the invention to provide an air conditioning system that uses a desiccant system to cool a structure.

It is another object of the invention to recycle water in an energy efficient system by utilizing gray water for purposes other than drinking in a structure.

It is another object of the invention to provide an energy efficient structure having a system utilizing solar power and efficient cooling and recycling to provide a structure capable of being self sufficient.

These and other objects of the present invention will be readily apparent upon review of the following detailed description of the invention and the accompanying drawings. These objects of the present invention are not exhaustive and are not to be construed as limiting the scope of the claimed invention. Further, it must be understood that no one embodiment of the present invention need include all of the aforementioned objects of the present invention. Rather, a given embodiment may include one or none of the aforementioned objects. Accordingly, these objects are not to be used to limit the scope of the claims of the present invention.


FIGS. 1A and 1B are a diagram of a HVAC and recycling system according to one aspect of the invention.


The present invention is to a heating and cooling system which can be used with a solar powered building. FIGS. 1A and B show an exemplary system in accordance with at least one aspect of the invention.

Solar power is becoming more important as fuel costs continue to rise and as more groups become interested in “green” technology. One such arrangement for a solar powered building is shown in co-pending U.S. patent application Ser. No. 11/948,029 filed Nov. 30, 2007, which is incorporated herein by reference.

The enclosed system may be used with such a building, but one skilled in the art would recognize that such a system could also be used with other energy systems presently existing or yet to be invented. However, preferably a solar collector 40 acting as a solar boiler is used in conjunction with the present system.

Referring to the drawings the HVAC system according to a preferred aspect of the invention will now be described. The system provides many of the HVAC systems required by a standard residence or commercial building, including heating, air conditioning and hot water.

Hot Water

Solar collectors can efficiently heat water without having to convert solar energy to electricity and back to heat. Solar boilers are thus preferred for providing heated water or other fluids as an output, rather than converting the heat to electricity, which must then be converted again later to the end use. The fluid exiting the boiler may be substantially heated and may reach 220-250 C, by using a fluid other than water. Without limiting the invention, a Hexane Octane mix may advantageously be used with its higher boiling point and efficient state transfers. Other fluids or refrigerants may be used in this or other cycles disclosed in this application. However, for simplicity and clarity “fluid,” “vapor,” “refrigerant,” or “water” may be used interchangeably throughout the application to refer to any fluid which can be used to transfer heat from one component to another, unless a particular required fluid is explicitly stated.

Heated water from the boiler may be sent through a vapor/liquid separator 42 with any liquid preferably returned to the inlet of the solar boiler. The return line serves two purposes, first to recycle any heated liquid back to the inlet to raise the overall temperature of the inlet fluid to help promote the generation of vapor. Secondly, the vapor is piped separately from the vapor to prevent the lower temperature, lower energy liquid from causing any premature condensation of the vapor back to liquid, thereby avoiding the waste of valuable energy in the vapor.

The vapor is then sent directly or indirectly to a heat exchanger 37 having an inlet T5 and outlet T6 for the heated vapor. The heat exchanger also has a separate inlet T51 for water (“cold water”) from a suitable source such as a well, storage tank or municipal water source. An outlet T61 carries away water (“hot water”) from the heat exchanger. Close contact of the water by appropriate piping, pressure caused by pumps, or by gravity feed will act to transfer heat from the heated fluid to the cold water to produce hot water. Appropriate valving and controls may be provided, for instance, to limit the outlet temperature of the hot water to prevent scalding, etc.

Using the hot water circuit described, solar power can be used to heat an intermediate fluid and to transfer heat from the intermediate fluid to cold water to produce hot water for use in a shower, laundry, etc. One skilled in the art would recognize that the cold water could also be heated by directly sending all or a portion of the cold water source through a solar collector to directly heat the cold water, but because of scaling (i.e., mineral deposit fall out caused by impure water sources) and for other reasons, indirect heating as described is preferred. Also, for the reasons described below, the solar boiler fluid may follow a circuitous path to the heat exchanger and the use of one boiler fluid may simplify parts of the HVAC system.


The system used to heat a building or other structure using the solar collector is analogous to heating hot water. However, instead of heating a cold water source, a cold air source is heated. The cool air source to be heated may be drawn from the outside, but is preferably recirculated from inside the house to save energy by reheating air at near room temperature rather than heating air at potentially a much colder outside air temperature. Humidification of the air may be used to condition air to the right humidity using well known techniques as necessary. As described later, one source of the humidification may be from the desiccant drier 42.

Air in the heating system is drawn through one or more suitable return vents 26,27 located about the structure. A heat exchanger or radiator 38 is provided having a first inlet T4 for heating vapor or fluid from the solar boiler and an outlet T5 for the vapor or fluid. Air from the return vents 26,27 is brought into contact with heat from the heating fluid in chamber 38 to heat the air. The air can then be distributed to one or more vents 45 in the structure to provide heating of the interior space. One skilled in the art would recognize that valves, thermostats and other controls may be implemented to control the amount of heating of the room and to provide adjustability of the room temperature selection.

The heating chamber 38 is shown upstream of the hot water heating system, but the systems may be in parallel, in series, independent or in other orders or combinations. Each system can be provided independently of the others or in conjunction with the other systems. However, the amount of energy removed from each system or the importance of each system may be taken into account when determining the order of the systems such that energy is used in the most efficient and effective manner to run all of the systems based on the expected energy from the solar collector and/or other energy input systems. For example, a back up generator may be provided to provide energy to the system when the solar system is overloaded or in disrepair, or municipal power may be provided when the solar system energy is deficient to run all of the systems.

Electrical Generation

Electrical energy may be required to run parts of the system, such as pumps, lights, or control systems. Solar panels may supplement the solar collector to convert solar energy directly into light. However, in addition to or in place of solar panels, the heated vapor may be converted into electrical energy as needed or to store energy for later use. One such system for converting heat and/or pressure to electrical energy is a STARROTOR™ expander generator that can be driven by the heated motive fluid to create electricity.

Referring t FIG. 1A, line T2 carries high energy, high heat vapor into expander generator 41. The expansion of gases causes rotation of a generator to create energy out for storage or other use. One skilled in the art would recognize that other pressure and or temperature converters could also be used. As another alternative, heated fluid can be stored for shorter period in an insulated tank or bladder for use later as necessary.

Air Conditioning

A heating fluid such as that generated at the exit T1 of the solar collector/boiler can also be used in an air conditioning circuit. One example of an air conditioning circuit is shown in the figures using a desiccant. In the example provided, CaCl2 is provided as the desiccant.

A water stripper 42 is provided to release vapor from the desiccant to provide concentrated desiccant for use in the air conditioning system. Dilute desiccant is pumped to the top of the water stripper 42 by pump 43. Heated fluid, such as vapor from solar boiler 40 is piped through a heat exchanger to heat the desiccant. The desiccant is sprayed or otherwise conveyed past the heat exchanger in the water stripper to heat the desiccant. The heated desiccant releases vapor and produces a highly concentrated desiccant. The water vapor can be recaptured to produce distilled water as is explained further hereunder.

Tank 43b below water stripper 42 is a tank that receives and mixed CaCl2 dilute desiccant from line C and from the concentrated desiccant from water stripper 42 into tank 43b. An inlet to tank 43b is controlled by a float valve 43C. The valve allows desiccant to flow into the tank when the level of the tank falls below a certain level. The outlet from the tank is controlled by a reversed float valve, that is, it operates in a manner reversed from the inlet valve. The float valve releases desiccant when the specific gravity is raised from higher concentrations of CaCl2. If necessary, the inlets for the concentrated desiccant and diluted desiccant may be controlled separately to adjust the concentration and level of the tank 43b.

The CaCl2 exiting tank 43b exiting at or above the desired concentration as determined by the specific gravity (i.e., the specific gravity of the desiccant is higher than that of water), is carried along line A for further processing into one of three tanks 21B (“cooling off/storage tanks) The desiccant is preferably stored in one or more of the tanks 21B until the desiccant has cooled to an ambient temperature.

The cooled, concentrated CaCl2 then exits the tank through line 21 to pump 22 into the condenser. The condenser has an automatic siphon that will irrigate a certain amount of CaCl2 into a media 13b via distribution panel 13. For instance plastic chips and sponge may be used to increase the effective surface area through which air can pass. Air flowing upwardly from the bottom of the condenser inner chamber will become drier as it surrenders moisture to the concentrated desiccant in the media 13b. As the desiccant absorbs moisture, it will also becomes warm. The warm desiccant begins to “drip” from the media and flow downwardly. Replacement desiccant is replace on top by the auto siphoning mechanism. The air coming out of tank 11 is roughly the temperature of the fluid, eg. 80 F. Cooling water could be circulated by heat exchanger 12 to further cool the media to add “surge cooling.” This cooling water could be from geothermal cooling such as by a subterranean water storage source naturally maintained at 55 F.

Dry air leaves tank 11 through line 11B into the bottom of evaporative cooling tank 15 where it passes through chips irrigated with water to cause evaporative cooling of the water evaporating due to the dry (“low humidity”) air. At the same time air becomes cool and moist. This provides both cool and relatively moist air in the house to the building through outlet 15C to appropriate vents or other access to the house.

The partially spent (“partially diluted”) desiccant from tank 11 is pumped by pump 11C into a surge tank 10. Surge tank 10 irrigates in layers the desiccant by media 5 via distribution panel 9. The fluid has slightly warmed in tank 11 and by pump 11C. The fluid is cooled in tank 11D, a second condenser tank. As the fluid flows down condenser 11D, it interacts with moist air. The air may be external air from the environment that interacts with air from the building that has been heated by the building. The desiccant seeps out the moisture from the air as it flows up through tank 11D and the desiccant flows downwardly. The fluid desiccant is cooled with the ambient air. The desiccant is thus cooled. Barrier 2B may be used to provide a barrier permeable to the air and desiccant while providing further surface for the interaction of the media and the air.

The spent CaCl2 loaded from water is sent to the stripper to be concentrated through line C.

Air from condenser 11D is somewhat cooled and dried by desiccant in tank 11D, passes through heat exchanger 3 and becomes somewhat cooler. The air then passes through tank 11 and becomes even drier. The air then is passed through tank 15 where through evaporative cooling becomes cooler and drier. From this tank it goes through the building and becomes somewhat warmer before entering the cycle again.

In a alternatively form, the air from the building 1, which is slightly cooled by coming from the air conditioned building could be precooled by heat exchanger 3 with air leaving the condenser.

Heating Fluid Return

Heating fluid from the boiler may be recycled for further use through the boiler. Once the heating fluid has completed one or more circuits, the fluid is preferably returned to a storage tank 36 for further use. Especially when water is not used as the heating fluid, the fluid must be pumped back for use at the inlet in order to effectively provide a closed circuit. Otherwise, fluid will have to be constantly added to the system. A tank such as that shown at 36 can be used to collect fluid after the energy has been extracted from the fluid. The fluid returning to the tank may help preheat the stored fluid prior to entrance to the solar collector as the system continues to operate adding more efficiencies to the system. A pump run by electrical energy provide by solar photaic cells or other power source can be used to provide fluid at the inlet to the solar collector. This is especially useful if the entrance to the solar collector is at the top of a building and the bottom of the solar collector or the systems described above are lower than the entrance to the solar collector 40. A heat exchanger 39 may be used to further preheat the fluid entering the solar collector, especially at start up or on cold days, etc. Preheating the fluid allows the system to heat more of the heating fluid into vapor to increase the efficiency of the system. A bypass valve 28 may be provided to bypass this preheating system when necessary.

Water Recycling

Because the solar collector and associated HVAC system may be used in a remote location, it may be important to conserve water as much as possible. One such “gray water” system is incorporated into the Figures, but the present HVAC system may be used with or without such as gray water system.

Water that is stripped from the desiccant either as vapor or water may be cleaned for potable water use or for other uses. The desiccant may be used in a known fashion to pull vapor out of the air, especially during night time when the system is not being used at its maximum rate and the cooler air has more humidity. This can be used to collect water otherwise unavailable to the occupants of the building. Once the water has been removed from the desiccant as condensate or vapor, the water is essentially purified as the desiccant is dried by heating the desiccant to produce water vapor. A collector at the bottom of the evaporator 42 collects the purified steam and moves the water to a storage location, such as a 500 gallon container 62. The water as this point is pure and can be used for food preparation, drinking or other ingestion. Water from the storage tank 62 may be used cold or heated for ingestion.

Collection of the water from sinks or other drainage may be collected for further use, know as grey wastewater. The water may then be filtered using Algae BOD (“Biological Oxygen Demand”) removal filters and solar energy to remove impurities from the water.

The BOD filter is a trough with vertical vanes so that water flowing along the trough flows down to the bottom and then up to the top repeatedly as it goes along the trough. The top of the trough has a transparent covering so that the water inside is heated and exposed to sunlight. The nutrients and light will support an Algae culture that will oxygenate the water, while other microbes convert the ammonia into nitrates. The Algae and microbes convert the carbon into aggregates that will sink. When the water flows downward out of light, other anaerobic microbes will dominate and consume the nitrates as an oxygen source resulting in nitrogen gas being formed and released. Thus the carbon and nitrogen nutrients are stripped out of the waste water. Upon filtration and sterilization, the water may be reused.

Any sedimentation may be removed and the water may be moved to a reverse osmosis filter to further purify the water. This water may then be used for laundry, showers, or other “secondary” uses. Part of the water may also be used to dilute incoming grey water to keep the Algae/BOD filter clean.

Water collected from the laundry, shower, may then be filtered and used in commodes, gardens, etc. through diverse filters or filters analogous to that described above. In this way a gallon of water is capable of meeting many uses before being discarded to the environment, conserving precious water in remote, arid environments or reducing municipal water filtration demands. This may also become more important in growing areas such as southern California where water demands are rising faster than supplies.

Retrieving the Moisture from the Air

During the summer, after the desiccant leaves the expander 41, there is a lot of heat still in the working fluid. That heat may be stored in the bladder 38 during the day. And at night, that heat may be used to activate the air siphon 38B. If you heat air in the siphon, a stack effect will be created. That is, if you have a column in a U shape tube, the heated air on one side will rise and will be drawn in the other side causing air circulation. In this way air is drawn in at entrance 26C and exits past valve 25 (bypassing the water stripper) to exit 46. Air enters 1B and through the media and is irrigated with desiccant, out through 18 to 45 and 46 exit. There may be appropriate valving to change the flow through the condenser. One skilled in the art would appreciate that a separate condenser for this cycle could also be use. In this way moisture is stripped from the outside air. The night air is already cool and has a higher relative humidity and it is therefore is easier to extract the water. As is evident in night air creating dew.

Specialized Air Treatment

In certain environments, it may also be desirable to treat the air prior to reentry into the building or structure. One such treatment may be the addition of chemicals, perfumes, medicaments or the like to the air to make the air more pleasing or more beneficial to the occupants, for instance adding medicaments to a nursery environment to aid the breathing of the occupants. A secondary tank 70 may introduce the chemicals, perfumes or medicaments to the evaporator 15 to treat the air prior to reintroduction of the air to the structure. One skilled in the art would appreciate that the materials could be added in an analogous manner to heated air, or could be added at a different location.

Chemicals or treatments could also be added to neutralize or remove deleterious materials from the air. For instance, chicken coops or houses often have adverse buildups of ammonia that can be a fire hazard or health hazard in higher concentrations. Tank 70 may be used to introduce an acid such as nitric acid, phosphoric acid or the like to the evaporator to neutralize the ammonia carried by the recirculated air from the chicken housing. Introduction of acid from tank 70 into evaporator 15 will cause the ammonia to form ammonium salts, such ammonium nitrate. The pH level of the water collected at the bottom of the evaporator will be lowered slightly. The collected water can then be recycled, cleaned or reused. In this way, the slight addition of acids to the evaporator can be used to take ammonia out of the air, avoiding the potentially hazardous build up of ammonia from the refuse.

Order of Components

The solar boiler heats the liquid in solar collector at 200-300C. The highest temperature fluid is then sent to the expander. The fluid exiting the expander will be fairly high, which can be used to preheat fluid to the solar collector or to strip the moisture from the desiccant. Or the heat can be stored in the bladder 38. In the heat storage bladder 38, there is a salt such as aluminum sulfate that is very soluble and has a very high water of hydration. You can adjust the ratio so that it will crystallize at a high temperature 80 C. If you heat it to 90 C, the salt will change phase. When you go from solid matrix to a fluid matrix, there is a large amount of energy released. It is the energy of change of phase. Therefore, although the tank is large, if it is stored as a solid, you can store a lot of energy. Potentially, in winter, the tank could be used for periods (eg., 5-6 days) without sunlight. The hot water heater ifs provided further downstream because of the lower temperatures required by the hot water heater. The stages allow you to practically use all of the energy before you finally cool it in 34 to be pumped through the cycle again.


The construction of the system may be made of materials that are environmentally friendly, or may be selected to be the most compact, the lightest weight, easiest to transport, etc. Most of the equipment required can be made of plastic, except for heat exchangers, etc. This allows for very cheap materials of construction and enhance portability of the system.

While this invention has been described as having a preferred design, it is understood that it is capable of further modifications, uses and/or adaptations of the invention following in general the principle of the invention and including such departures from the present disclosure as come within the known or customary practice in the art to which the invention pertains and as maybe applied to the central features hereinbefore set forth, and fall within the scope of the invention and the limits of any appended claims.