Waste Heat Air Conditioner
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A system for use as an air conditioning and heating system that uses waste heat to dehydrate a desiccant. The desiccant is then used to dry air. A water sprayed onto an extended, fanned surface is used to harness evaporative cooling of air in contact with the evaporator surface. According to one aspect of the invention, plant spray irrigation surfaces are used as a means to expose water in a dried air environment to cool the air by contact and to produce cool air. The combination of cooled and dried air produces a comfortable environment, i.e., air conditioning.

De Lima, Daniel D. (Norfolk, VA, US)
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International Classes:
F25B27/00; F25B17/00
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Primary Examiner:
Attorney, Agent or Firm:
I claim:

1. A cooling system for providing warm, dry air, comprising: a. providing hot water to a heat exchanger; b. flowing a desiccant through the heat exchanger to heat the desiccant to remove water from the desiccant; c. transferring the dried desiccant to a storage tank; d. communicating internal air from a room to be conditioned; e. passing the internal air over a ceramic bed into an external chamber; f. cooling air in the external chamber using a flow of external ambient air; g. moving the internal air to an internal chamber; h. cooling the internal air with a second flow of external ambient air; i. removing a concentrated desiccant from the storage tank and spraying the desiccant onto internal air in the internal chamber to dry the internal air; j. communicating the dried, cooled internal air to the room to be conditioned.



This application claims the benefit of U.S. Provisional Application 61/061,683, filed Jun. 16, 2008, entitled Waste Heat Air Conditioner, which is incorporated herein by reference.


1. Field of the Invention

The present invention relates in at least one aspect to a heating and cooling system which can be used for example with a solar powered building, though the solar powered building is not necessary for the invention.


The present invention shows according to some aspects of the invention a system for utilizing a heated fluid to provide air conditioning for a building. Hot water or other fluids are easier to maintain and come by in a primitive air condition system that compressors, and refrigerant systems and are thus desirable in remote locations or for more environmentally friendly systems. Hot water can be produced for example by a solar heater. The hot water can be used with an evaporator to strip heat and water/vapor from desiccants. This system in addition to an evaporative cooler in the form of a green house room can be used to provide cool, moist air. For heating, the use of a ceramic matrix can be serially connected to a desiccant-air drying chamber to produce dry, warm air.

Accordingly, it is a principal object of a preferred embodiment of the invention to provide an environmentally friendly heating and air conditioning that relies only on hot water to produce warm, dry air or cool, moist air to condition a building or room.

It is another object of the invention to provide a desiccant cycle that uses hot water to dry the desiccant for use in an HVAC system.

It is a further object of the invention to use reversible flow through a ceramic matrix to pre heat or pre-cool air.

Still another object of the invention is to provide a heater/cooler that uses ambient air to process air and desiccant to dry air.

It is an object of the invention to provide improved elements and arrangements thereof in an apparatus for the purposes described which is inexpensive, dependable and fully effective in accomplishing its intended purposes.

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.


FIG. 1 is diagrammatic view of the heating and air conditioning system according to an aspect of the invention.

FIG. 2. is a diagrammatic view of an evaporative cooling chamber according to one aspect of the invention.

FIGS. 3A and 3B are diagrammatic views of a natural louver system for use with an embodiment of the invention.

FIGS. 4A and 4B are diagrammatic views of a heating and cooling feature of one aspect of the invention.

Similar reference characters denote corresponding features consistently throughout the attached drawings.


The present invention is to a heating and cooling system which can be used for example with a solar powered building, though the solar powered building is not necessary for the invention. The Figures 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 copending 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 (not shown) acting as a solar boiler is used in conjunction with the present system. In particular, waste heat from a generator or expanded steam from a solar boiler may be used as a source of waste heat to run the present system. In view of the trend of high energy prices and the desirability of minimizing CO2 generation, the use of waste heat to produce air conditioning is beneficial. This is especially appropriate with line solar boilers where the waste heat after expansion in an expander generator is about 150° C., and where the maximum waste heat is produced about noon, coincidental with the highest electricity production and costs.

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 components required by a standard residence or commercial building, including heating, air conditioning and hot water.

In general, the system is an air conditioning and heating system that uses waste heat to dehydrate a desiccant. The desiccant is then used to dry air. A water sprayed onto an extended, fanned surface is used to harness evaporative cooling of air in contact with the evaporator surface. According to one aspect of the invention, plant spray irrigation surfaces are used as a means to expose water in a dried air environment to cool the air by contact and to produce cool air. The combination of cooled and dried air produces a comfortable environment, i.e., air conditioning.

Referring now to the drawings, a description of an illustrative embodiment of the invention will be shown. A waste heat air condition and heating system is shown. A heated fluid is provided as inlet 12 to a heat exchanger 14. The heated fluid may be waste heat from a solar boiler or may be provided from any other source. The heated fluid flows through the heat exchanger in close relation to a saturated desiccant flow 16. The heated fluid 12 will leave the heat exchanger slightly cooler and the saturated desiccant will leave slightly hotter. As the desiccant heats, it will lose fluid in the form of vapor and become dryer. Alternatively or in addition, the saturated desiccant may be sprayed by nozzles 20 onto heated surfaces of evaporation coil 22 causing water in the saturated desiccant to vaporize leaving dryer (“less saturated” desiccant). Valving may be provided through out the system to direct flows called for herein.

The vaporized water released during contact with heated coils 22 rises over the top of the chamber 30 and is condensed in condenser 32. The condensed vapor is collected in a water tank 36. Because the water is condensed vapor, the water has been purified and may be used as potable water or for other purposes, as described later hereinunder. Vapor that has not condensed may travel past the condenser and travel back up past the evaporation coil 22 under the force of a fan, convection currents or the like. Since the vapor is traveling opposite the downward flowing saturated desiccant, it can be an efficient aid in heating the desiccant to produce vapor as discussed above.

Desiccant that is concentrated during vapor is released is collected in a concentration tank 40. A float 42 causes desiccant to be pumped out of the tank 40 via pump 44 back to the evaporator/heater for further concentration until the desiccant reaches a predetermined concentration level. Concentrated desiccant (i.e., that with a specific gravity lower than water, or greater, depending on the desiccant used) is then released from the tank 40 by the float rising to allow only optimally concentrated desiccant to flow through line 46 to a storage tank 50, i.e., that having a specific gravity high enough to raise the float 42. The float releases a valve allowing concentrated desiccant to flow out or be pumped out of the tank. If the desiccant has too much water it will be less dense and will not raise the float and the desiccant will instead flow back through pump 44 for further processing.

The desiccant in tank 40 has been cooled by the release of vapor and the desiccant stored in the storage tank 50 is cool. Multiple parallel or serial tanks may be provided as needed. The storage tanks also allow the desiccant drying/concentrating cycle to be run when waste heat is available instead of on-demand or based on desiccant levels. This separation of the drying cycle from the air condition cycle described below allows the system to achieve greater efficiencies.

The cooled desiccant in tank(s) 50 is sent to the air heater/cooler 110. A matrix of rocks or other ceramic material 112,114 is provided on either side of the main chamber 116. These tanks are separate and independent from each other and the main chamber. The rocks 118 or other ceramics are heated and cooled by flows through the system to act as a preheater/precooler and as a temperature storage device.

In operation, air from a conditioned environment such as a room or a house or commercial building is drawn initially in inlet 120. In the heating mode, the rocks 118 at the top of matrix 114 will be slightly warmer than the inlet air. The cool inlet air will tend to slightly cool the rocks until the rocks at the top are slightly cooler than the rocks at the bottom as the air is slightly heated as it passes over the rocks. A fan 122 may be used to blow the moist air over the rocks and promote heat transfer. Since the air has been previously treated for use in the conditioned room, it will be moist. The air will travel through the rocks to the inner chamber 116 through a flap valve 124. Because the internal air is being heated, it must be warmer than the air outside that is not being heated. At the same time, external air in an ambient line 130 enters the system typically much cooler than the recycled air internal air received at 120. The external air is directed through heat exchange coils 131 through the external chamber to cool the internal air. The heat exchange between the outside air and the recycled air cools the recycled air to near ambient (“outside”) temperatures as the processed internal air rises in chamber 116. At the top of chamber 116, the air enters the internal chamber 132 through one or more flap valves 134.

The internal air chamber 132 acts as an air dryer. Several different flows combine to dry the air. One such flow is provided by a second outside air inlet 136 that brings cool air through the inner chamber 132 in contact with air traveling down the inner chamber. Dehydrated desiccant from tank 50 is simultaneously pumped to the top of internal chamber 132 where it is sprayed in contact with (“trickled over”) the air traveling down the chamber. The desiccant absorbs moisture from the air drying the air, warming the air and desiccant in the process due to heat of condensation. However, the small amount of warmth transferred to the air in the chamber is cooled by the external air in cooling tube 138. Air from both inlet 130 and 136 are released back to the environment by stack 140 having served their purpose of cooling the air.

The processed internal air then exits the internal chamber 132 through a flap valve to the second outer chamber 112 having a rock or ceramic matrix at close to the ambient temperature. This valve may be, for example, pressure operated. Analogous to outer chamber 118, the rocks at the top are slightly cooler than those at the bottom. As the air passes through the rocks, the air is gradually slightly cooled as it passes over the increasingly cool rocks, exiting as cool dry air. In this way, the rocks in chamber 114 become slightly cooler from the entering air and the rocks in chamber 112 become gradually warmer, from the relatively warm, dry air leaving through exit 142.

Before the rocks reach the temperature of the air across them, the flow is reversed. Fan 144 is turned on and fan 122 is turned off. Flow then proceeds from the inlet 142 over the slightly cooled matrix in chamber 112 into the outer chamber 116 past ambient air exchanger 131 into inner chamber 132. Inside the air chamber, the air contacts the desiccant from nozzles 135 and over ambient air surfaces 138 out a flap valve to chamber 114 where the air is slightly cooled and exits outlet 120. It should be noted that “warm” and “cold” are relative to ambient, external temperature and not relative to the controlled environment of the room being treated.

Only a portion of the air actually is reversed. Air in the inner chamber 132 and outer chamber 116 do not experience the reverse flow as the chambers are located between the two matrix chambers and air flow merely flows in and out different valves located near each other.

Heat exits the system in several ways. First, ambient air from inlets 130, 136 that have been heated in inner or outer chamber leave the system at stack 140 taking whatever heat they absorbed. Additionally, saturated desiccant has absorbed water and gained heat of condensation in inner chamber 132. This slightly saturated desiccant is sent to tank 40 for drying and other processing carrying the heat away from the internal chamber.

Air from outlet 120 or 144 may be sent to an evaporator for further conditioning, if necessary. An evaporator 150 comprises a small room or compartment similar to a green house that can be used in conjunction with or separately from the heating and cooling system described above. Air enters a suitable inlet such as inlet 156. The cool dry air absorbs water in the form of vapor from nozzles or spray jets 152. Water is also provided by droplets on plants 154, leaves or soil in the evaporator chamber. The water may be pumped or provided by tank 36 and filtered or may collected rain water or from other sources. As water evaporates, the air becomes cooler as the heat of vaporization is subtracted from the environment. The air also becomes more humid, a desirable condition in air conditioning. Thus the air is cooled and humidified by the evaporator, ready to be expelled through outlet 160 to a room to be conditioned.

Excess water that is not absorbed from the air may be filtered through the soil and leaves and trapped at a lower compartment for return to tank 36 or for processing before further reuse. Filtering may be for instance by filter paper, membranes, gravel 164 or the like. A fan 166 or other motivating force may be used to increase contact of the air with vapor, water drops on the plants, etc.

A second fan 167 may be used for drawing air from the chamber 150 and pumping through the gravel 164 through the soil back to the chamber. The contact with the damp, porous topsoil 168 will act to contact the air with microbes in the soil that will remove most of the organic contaminants from the air.

An upper surface 170 of the evaporator chamber 150 may be made of transparent or translucent material such as plastic or glass. This surface may be used to heat the interior space as desired. Louvers or other light controls may be used to block light when the air is being cooled and opened when air is being heated. In an alternate embodiment, a trellis or other screen 172 (FIGS. 3A & 3B) is provided above the surface 170. The trellis may be covered with a plant material. The plant may be selected such that reduced vegetation or foliage during winter allows sunlight (“solar heat”) to easily reach the chamber 150 and during the summer, increased foliage 174 blocks light from reaching the chamber 150.

FIGS. 4A and 4B show an air exchanger 180 that can be used with or separately from the above system. A reversible air exchanger 180 includes an inlet/outlet 182 for internal air and an inlet/outlet 186 for external air. Only one inlet and one outlet are in use at any time. To exchange internal air and external air, a fan 184 is switched on and run in the proper direction to bring internal air in through inlet 182. Air travels through the inlet 182 and slightly warms the rocks of the matrix 188 before being sucked out of the chamber 190 through outlet 186. After a set amount of time, the system is reversed and air in sucked in inlet 186 by reversing fan 184. The air is blown across the matrix 188 that has been slightly warmed by the previously flow of internal air. The matrix acts to heat the ambient air to preheat the ambient air to reduce the load on the system.

It is also envisioned that the waste heat could be used at any point in the system to heat moist or dry air as needed to supply heated air to a conditioned room. The heat can be transferred to the air, for example, through a heat exchanger (“radiator”) or by other means.

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 the appended claims. It is therefore to be understood that the present invention is not limited to the sole embodiment described above, but encompasses any and all embodiments within the scope of the following claims.