Abstract:
A desiccant air conditioning system for heating an air stream entering a building space includes a conditioner having multiple structures arranged in a substantially vertical orientation. The structures are spaced apart from each other with an air stream gap between each pair of adjacent structures. Each structure has at least one outer surface facing an air stream gap across which a liquid desiccant can flow. An air stream flows through the air stream gaps between the structures such that the liquid desiccant humidifies the air stream. Each structure further includes a separate desiccant collector at a lower end of the at least one outer surface for collecting liquid desiccant that has flowed across the at least one outer surface of the structure. The desiccant collectors are spaced apart from each other to permit airflow therebetween. The conditioner also includes a heat source for heating a heat transfer fluid used to heat the liquid desiccant.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a division of U.S. patent application Ser. No. 13/115,686 filed on May 25, 2011 and entitled METHODS AND SYSTEMS FOR DESICCANT AIR CONDITIONING, which claims priority from U.S. Provisional Patent Application Ser. No. 61/348,076 filed on May 25, 2010 and entitled SOLAR AIR-CONDITIONING AND HEATING SYSTEMS and U.S. Provisional Patent Application Ser. No. 61/430,692 filed on Jan. 7, 2011 and entitled METHODS AND SYSTEMS FOR DESICCANT AIR CONDITIONING, all of which are hereby incorporated by reference. 
    
    
     BACKGROUND 
     The present application relates generally to air conditioning, capturing combustion contaminants, desalination, and other processes using liquid desiccants. 
     The term “air conditioning” generally refers to the treatment of air going into a building space, including to the heating, cooling, humidity adjustment, or purification of air that enters or leaves the space. It is well known that air conditioning is an enormous source of energy use and that summer cooling in particular can lead to electricity grid problems. Air conditioning is often the largest operating cost in a building. 
     Current air conditioning systems for cooling are generally based on the compression of a gas such as Freon and the expansion of the compressed gas through a valve assembly. However, in order to reach the required humidity levels of the entering air into a building, the air generally needs to be overcooled in order to condense water vapor into liquid water. This dehumidification (latent cooling) generally uses more energy in an air conditioning system than the physical lowering of the air temperature (sensible cooling). Oftentimes re-heaters are employed within an air conditioner requiring even larger amounts of energy. 
     Air conditioning for heating air is typically done by combustion of natural gas or some other fuel. The combustion often heats a heat transfer fluid that is then directed to a fan coil unit where the entering air is heated. In many buildings, such sensible only heating results in humidity levels that are too low for comfort. Oftentimes humidifiers are integrated with the heating system. Such humidification however results in the cooling of the air, which means that additional heating will have to be applied to counteract the cooling effect of the humidifier. 
     Solid desiccant systems have been used for many years primarily for summer cooling. However, the heating effect that occurs when air is dehumidified in an adiabatic fashion (no heat is added or removed) requires large amounts of sensible cooling post-dehumidification and as a result limits the energy savings that can be obtained. 
     Absorption chillers such as units manufactured by Yazaki Energy Systems typically utilize a low pressure vacuum vessel in which a desiccant material is contained (in Yazaki&#39;s case LiBr2 and water, but systems using Silica gel have also been developed). However, the use of low pressure vacuum systems significantly increases the cost and complexity of the equipment and increases the requirements for maintenance. Also, each transition (from air to a heat transfer fluid to the desiccant) utilizes heat exchangers, fans, and pumps and thus results in higher costs. And importantly, such transitions result in larger temperature requirements since each transition is not perfectly efficient. As a result, absorption chillers require higher temperatures to operate making them less suitable for integration with systems that employ waste heat or low grade heat. 
     More recently systems have been introduced that employ other methods for dehumidification of the air. Liquid desiccant systems such as the systems manufactured by DuCool and Agam use a strong desiccant material such as a CaCl 2  and water or LiCl 2  and water solution to absorb water vapor in the air. The liquid desiccant is directly exposed to the air unlike the previously discussed absorption chillers that do not have air to desiccant direct contact. After the desiccant absorbs moisture from the air stream, it is heated to release the excess water. In winter, such desiccants can be used to recover heat and moisture from the leaving air and transfer it to the incoming air. 
     Liquid desiccant systems however have traditionally suffered from the risk of desiccant carry-over into the air stream resulting in sometimes severe corrosion problems in the building since the desiccants that are used are typically strongly corrosive to metals. 
     Furthermore, liquid desiccant systems are typically spraying a liquid desiccant on a filter media to increase the surface area of desiccant exposed to the air. The spraying increases the risk of desiccant carryover into the air stream. Oftentimes additional mist eliminator filters are used to capture any airborne desiccant particles. However, these mist eliminators require frequent maintenance and replacement. Furthermore, the process of using a filter media is inherently energy inefficient. The filter media is an obstruction in the air flow and thus generally requires large fan power. Also, the filter media typically are thermally non-conductive which makes the dehumidification process adiabatic resulting in undesirable heating of the air. To counteract the heating effect, one can increase the flow rate of the desiccant and one can pre-cool the desiccant to achieve some level of sensible cooling at the dehumidification stage in the filter media. Increasing the flow rate of course increases the risk of desiccant carry over and requires more liquid pump power. The liquid desiccant typically “rains” down from the filter media into a liquid desiccant collection pan. This generally prevents the liquid desiccant system from using a vertical air flow and requires more costly duct work to be used during the installation of the system on a buildings roof, where air is typically handled vertically. Furthermore, the drain pans do not easily allow the system to be set up as a “split” system wherein the conditioner and regenerator are located in physically separate locations. In addition, the drain pans do not easily allow for the system to be expandable: one has to increase the size of the pan—which means a new design, rather than adding capacity through a scalable design. 
     AIL Research has developed a low flow desiccant system that overcomes some of the objections mentioned above. The use of a heat transfer fluid in-situ to where the desiccant is dehumidifying the air results in better thermal performance and lower fan and pump power. However this approach still utilizes a horizontal air flow—which makes it much harder to integrate to a rooftop installation—and a very complex conditioner design that has a desiccant drain pan at the bottom, but does not allow for a counter flow between the air and the liquids. This system also still has the risk of desiccant carryover since the desiccant is still directly exposed to the air flow. 
     The source of heat and the required temperature for regeneration of the desiccant is also an important consideration in the design of a solar air conditioning system. It should be clear that the lower the regeneration temperature of the desiccant is, the easier it should be to find a source of such (waste) heat. Higher regeneration temperatures necessitate higher quality (temperature) heat sources and thus are less easily available. At worst, the system has to be powered by a non-waste heat source such as a hot water furnace. Yazaki absorption units have been powered by evacuated tube solar thermal modules that are able to generate heat as high as 100° C. Concentrated solar thermal modules are able to achieve even higher temperatures, but oftentimes do so at higher costs. Glazed flat plate solar thermal collectors typically operate at somewhat lower temperatures of 70-80° C., but also lose a significant portion of their efficiency at higher temperature, which means that the array size needs to be increased to generate adequate power. Unglazed flat plate solar thermal collectors have higher efficiencies at lower temperatures, but generally lose a lot of their efficiency at high temperatures and are usually not able to achieve temperatures higher than 60° C., making them unsuitable for integration with absorption chillers. 
     None of the solar heat sources mentioned above (concentrated solar thermal, evacuated tube collectors and glazed and unglazed flat plate collectors) generates electricity at the same time as generating heat. However, all air conditioning systems still require electricity for fans and liquid pumps. Electricity is oftentimes much more expensive per unit of energy than fuels used for heat. It is therefore desirable to have an energy source that can provide heat as well as electricity. 
     It is known that solar Photo-Voltaic Modules (PV modules) heat up significantly in direct sun exposure with temperatures approaching 70-80° C. Such temperatures have a deteriorating effect on the performance of the module since module performance degrades with an increase in temperature. Applying a thermal transfer fluid to the back of the PV module (a module known as a PVT (PV-Thermal) module) effectively draws the heat from the module, lowering its temperature and increasing its efficiency. The thermal transfer fluid (typically water or water and propylene or ethylene glycol) can reach temperatures and thermal efficiencies typically between those of a glazed and an unglazed solar thermal module. 
     From a cost perspective, solar thermal systems augmented with conventional PV modules are less cost effective than PVT modules and take up more space than PVT modules. However, PVT modules generally supply lower temperatures and efficiencies than pure solar thermal systems. But beneficially they generate more electricity than conventional PV modules. 
     BRIEF SUMMARY 
     As discussed in further detail below, various embodiments disclosed herein are directed to methods and systems for air conditioning, capturing combustion contaminants, desalination, and other processes using liquid desiccants. 
     In accordance with one or more embodiments, solar Photo Voltaic-Thermal (PVT) modules are connected to a desiccant air conditioning system to heat desiccants. The PVT modules can be connected in various arrangements for summer cooling and winter heating. The air conditioning systems can include both horizontal and vertical air flow desiccant systems, including spray-head desiccant systems. 
     In accordance with one or more embodiments, the PVT modules can be used to provide cold water for a desiccant system for summer cooling. 
     In accordance with one or more embodiments, the PVT modules can be used to provide heat for water going to a humidifier of air in a desiccant air conditioning system. 
     In accordance with one or more embodiments, the air conditioning systems can include a set of hollow plate structures used to expose desiccant to an air flow. In accordance with one or more embodiments, the plate structures have a wavy shape aspect to them. The hollow wavy plate structures are constructed in such a way that the surface tension of the liquid desiccant is used to draw the liquid desiccant into a drain channel. In accordance with one or more further embodiments, a sheet material such as a membrane or wetting material can be arranged on the wavy plates to guide a liquid desiccant into the drain channel. A membrane can be a micro-porous membrane with pores ranging in size from typically from 0.01 μm to 1 μm. An example of such a membrane is a membrane made by Celgard of Charlotte, N.C., and a division of Polypore Corporation, under the type designation EZ2090. 
     In accordance with one or more embodiments a membrane is a micro-porous membrane backed by a material intended to evenly distribute a liquid. In embodiments a membrane is a hydrophobic microporous membrane. In embodiments the backing material is a hydrophilic material such as a wicking material. An example of such a wicking material is the interfacing material made by the Pellon Company of New York, N.Y. 
     In accordance with one or more embodiments, the wavy plate structures are arranged in the air conditioning system such that the liquid desiccant is exposed to a vertical air flow without substantially obstructing the air flow. 
     In accordance with one or more embodiments, multiple sets of wavy plate structures can be arranged into a stack that has a scalable nature wherein the drying or wetting capacity of the desiccant can easily be expanded by simply adding additional wavy plates. 
     In accordance with one or more embodiments, a membrane desiccant system is provided for an air conditioning system using counter-flows of liquids and air in a vertical air flow system. 
     In accordance with one or more embodiments, a membrane desiccant system is provided wherein a membrane or other hydrophobic material is bonded to a wetting or other hydrophilic material in such a way as the provide proper distribution of a liquid behind the membrane. In embodiments to a double layer is bonded to a (thermally conductive) hydrophobic structure such as a plastic cooling channel or support plate. 
     In accordance with one or more embodiments, the plate construction allows for spreading a liquid desiccant at the top of a plate and for collecting such desiccant at the bottom of the plate. 
     In accordance with one or more embodiments, the air flow going to a vertical air flow desiccant set of wavy plates is preheated, and the air leaving a set of plate structures is post-cooled. 
     In accordance with one or more embodiments, plate structures are constructed and assembled in such a way that the plates can thermally conduct heat, but are still corrosion resistant by employing a thermally conductive plastic material. In embodiments such a plastic has a thermal conductance of about 5 to 10 W/mK. As an example thermal conductances for regular plastics range from 0.1 to 0.5 W/mK, whereas Copper, Aluminum, Stainless Steel and Titanium have a conductance of about 400, 250, 16 and 18 W/mK respectively. Of these materials only Titanium is reasonably suitable for use with desiccants such as CaCl 2  or LiCl 2  due to the corrosive nature of the desiccants. 
     In accordance with one or more embodiments, plate structures are assembled using a header that can be stacked vertically as well as horizontally in such a way that the wavy plates can be stacked parallel to each other as well as on top of each other. 
     In accordance with one or more embodiments, plate structures are assembled in such a way that a membrane is mounted on each plate to guide liquid desiccant to a header at the bottom of the wavy plate. 
     In accordance with one or more embodiments, the air inlet to the plate structures is disturbed by a mesh or set of disturbance plates in such a way as to create turbulent air movement in the air entering the wavy plates. 
     In accordance with one or more embodiments, a solar inverter is integrated an air conditioning system in such a way that the electrical connections to the air conditioning system provide the electrical connection to the building for a set of solar modules. In some embodiments, the air conditioning unit is a desiccant air conditioning system. In some embodiments, the desiccant air conditioning system uses vertical air flows. In some embodiments, the solar modules are PVT modules. 
     In accordance with one or more embodiments, a liquid desiccant vertical air flow system utilizes a chiller as a source of cold water and a gas water heater as a source for warm water, wherein the gas water heater is supplemented by the heat generated by solar modules. 
     In accordance with one or more embodiments, a PVT module provides electrical power and heat to a desiccant air conditioning system and provides heat to a water storage tank. The hot water can gradually be stored in tanks underneath the PVT modules, and the electrical power can be used to operate the air conditioning system. Any excess electrical power can be provided to other devices. 
     In accordance with one or more embodiments, PVT modules are set up in such a way as to radiate heat during the night, and thus provide cooling of water. Such cooled water can be stored in water storage tanks so that it can be made available during the day for the cold side of a desiccant air conditioning system. In some embodiments, such cold water can also be generated at night using an evaporative chiller in combination with the PVT modules. 
     In accordance with one or more embodiments, a PVT module generates hot water that is regulated by a thermostatic switch so as to enter a tank or flow directly to a manifold. In some embodiments, the thermostatic switch is driven by the temperature of the hot water. In some embodiments, the switch is operated by remote control. 
     In accordance with one or more embodiments, water is stored in a tank underneath a PVT module in such a way that the tank provides adequate evenly distributed weight to function as a ballast and support system for the PVT module. In some embodiments, the tank has a removable lid. In some embodiments, the tank can furthermore function as a shipping container for the module. 
     In one or more embodiments, PVT modules are connected to a plate structure desiccant system. In some embodiments, the wavy plate system is set up to provide cool air to a building. In some embodiments, the wavy plate system is set up to provide warm moist air to a building space. 
     In accordance with one or more embodiments, PVT modules are connected so that they preheat water that is destined to go into a humidifier for air destined for a building space. 
     In accordance with one or more embodiments, a desiccant is separated into various layers in a vessel wherein the concentration of the desiccant varies along the height of a vessel. In some embodiments, the vessel is used to provide and collect desiccant to a desiccant air conditioning system. In some embodiments, at least one of the outlets of the vessel is adjustable so that different layers with different desiccant concentrations can be selectively drawn from the vessel. 
     In accordance with one or more embodiments, a portion of an air flow treated by a plate conditioner in such a way that the humidity is reduced is diverted to an additional set of plates that provides cooling of the air through evaporation of water vapor. In some embodiments, such a system uses membranes on the surface of the plates. In some embodiments, the air flow across the second set of plates can be reversed and the water for evaporation replaced by a desiccant in such a way that during winter operation, it provides additional heating capacity of the air entering the building. 
     In accordance with one or more embodiments, a set of plate structures provides an evaporative cooling effect and the so produced chilled liquid is directed to both a conditioner as well as one or more liquid to air heat exchangers. In embodiments such liquid to air heat exchangers are ceiling panels. In embodiments such liquid to air heat exchangers are fan coils. In embodiments such fan coils are located inside ductwork. In embodiments such liquid to air heat exchangers are located underneath a floor. 
     In accordance with one or more embodiments, a series of holes is provided at the top of the membrane to inhibit vacuum lock and allow for easy draining of desiccant from behind the membrane covering a plate structure. 
     In accordance with one or more embodiments, a plate structure is constructed in such a way as to provide alternating access to water and liquid desiccant on the surface of the plates by providing holes on an asymmetrical pattern. 
     In accordance with one or more embodiments, a heat exchanger is constructed using thermally conductive plastic plates to provide heat transfer between corrosive fluids. In some embodiments, such a plate heat exchanger uses horizontal and vertical counter flows. In some embodiments, the thermally conductive plates are formed in such a way as to have ridges and features that promote heat exchange and are constructed so that they can be stacked and sealed. In some embodiments, the thermally conductive plastic plates are not formed, but rather a gluing material is used to create and attach ridges on the top and/or on the bottom of the plastic plates. In some embodiments, the gluing material is also used to provide a seal to the liquids in between the plates. In embodiments the glue ridges are shaped in such a way that the ridges on the lower plate are supporting the ridges on the top of the upper plate, while the seal glue spans the entire gap between the two plates. In embodiments, the glue material is Marine 5200, made by 3M Corporation of St. Paul, Minn. 
     In accordance with one or more embodiments, a first set of plate structures is contained in a hermetically sealed container and wherein a second set of plates is contained on the opposite side of the container. The first set of plates contains an optional membrane over its surface or a wetting material. The first set of plates receives a diluted desiccant from a desiccant source. The first set of plates also receives a heated heat transfer fluid from a source. A fan provides air movement inside the hermitically sealed container in such a way that water vapor is taken from the first set of plates. The second set of plates is relatively cool compared to the air environment and the enclosure in such a way as to cause condensation of water on its surfaces. The water can be withdrawn from the sealed enclosure. In some embodiments, the second set of plates is cooled by an external cold source. 
     In accordance with one or more embodiments, a set of plate structures with a liquid desiccant exposed to its surface collects moisture from an air stream and directs the diluted desiccant to a hermitically sealed container wherein the desiccant is regenerated and wherein the water vapor is recovered in the form of liquid water. In some embodiments, the heat for the system is provided by solar thermal modules. In some embodiments, the heat for the system is provided by PVT modules. 
     In accordance with one or more embodiments, a liquid desiccant is first regenerated in a hermitically sealed container and subsequently regenerated in an open array of plate structures. In some embodiments, the water recovered in the hermitically sealed container is diverted to a set of plate structures providing an evaporative cooling effect. 
     In accordance with one or more embodiments, fuel combustion takes place in such a way that the effluent gasses are directed through a set of plate structures having a liquid desiccant on its surfaces. The effluent gasses contain substances such as Carbon Dioxide, Water Vapor and contaminants such as SO x  and NO x , which can be captured into the desiccant. In some embodiments, the desiccant is regenerated into a concentrated desiccant and liquid water. In some embodiments, the desiccant is filtered in such a way as to remove acidity created by the SO x  and NO x  and other gasses absorbed from the fuel combustion process. 
     In accordance with one or more embodiments, a desiccant draws water through a membrane from a water source such as seawater. The concentrated desiccant is diluted as a result of the transition of water through such membrane. The diluted desiccant is transported to a hermetically sealed enclosure wherein the desiccant is regenerated in such a way that concentrated desiccant and liquid water are produced. In some embodiments, the heat for regeneration is provided by solar thermal modules. In some embodiments, the heat for regeneration is provided by PVT modules. 
     Many construction variations can be envisioned to combine the various elements mentioned above each with its own advantages and disadvantages. The present invention in no way is limited to a particular set or combination of such elements. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIG. 1A  illustrates a desiccant air handling system using a shower head design in accordance with the prior art. 
         FIG. 1B  illustrates a desiccant air handling system using a plate design and horizontal air flow in accordance with the prior art. 
         FIG. 2A  shows a desiccant air handling system set up for extreme summer operation with cold source and PV/Thermal module tie-in in accordance with one or more embodiments. 
         FIG. 2B  shows a desiccant air handling system set up for non-extreme summer operation with cold source and PV/Thermal module tie-in in accordance with one or more embodiments. 
         FIG. 3A  shows a desiccant air handling system set up for extreme winter operation with cold source and PV/Thermal module tie-in in accordance with one or more embodiments. 
         FIG. 3B  shows a desiccant air handling system set up for non-extreme winter operation with cold source and PV/Thermal module tie-in in accordance with one or more embodiments. 
         FIG. 4  shows the integration between a building&#39;s existing air conditioning system, a desiccant air conditioning system and PVT modules in accordance with one or more embodiments. 
         FIG. 5  shows a desiccant system employing a vertical air flow in accordance with one or more embodiments. 
         FIG. 6A  depicts a three-dimensional view of the system of  FIG. 5  in accordance with one or more embodiments. 
         FIG. 6B  depicts one or more turbulence plates that create air turbulence in the air entering a set of plate structures. 
         FIG. 7  shows the vertical air flow desiccant system with optional pre- and post air treatment coils and heat pump system in accordance with one or more embodiments. 
         FIG. 8  depicts details around the wavy plate structures in accordance with one or more embodiments. 
         FIG. 9  shows a possible construction for the wavy plate structures in accordance with one or more embodiments. 
         FIG. 10A  shows an alternative method for wavy plate structure assembly, including the mounting of a membrane or wicking material in accordance with one or more embodiments. 
         FIG. 10B  shows a cross section of two membranes with a hydrophilic wicking material sandwiched in between two hydrophobic membranes wherein the wicking material spreads a liquid uniformly between the two membranes in accordance with one or more embodiments. 
         FIG. 10C  shows a cross section of a hydrophobic membrane, a hydrophilic wicking material and a (thermally conductive) support wall in accordance with one or more embodiments. 
         FIG. 10D  shows a cross section of two membranes with two wicking materials and an internal (thermally conductive) support wall in accordance with one or more embodiments. 
         FIG. 10E  shows a cross section of two membranes with two wicking materials and an internally hollow (thermally conductive) support wall in accordance with one or more embodiments. 
         FIG. 11A  shows how the plate structures can be stacked into larger arrays and depicts construction details in accordance with one or more embodiments. 
         FIG. 11B  illustrates desiccant system employing a horizontal air flow through two conditioners in accordance with one or more embodiments, wherein the air is treated twice by plates that are oriented at an angle to the air flow. 
         FIG. 11C  shows a top view of the embodiment of  FIG. 11B . 
         FIG. 11D  shows the arrangement from  FIG. 11B  replicated twice in such a way as to treat the incoming air into a space and to recover energy from the returning air in a second set of conditioners in accordance with one or more embodiments. 
         FIG. 11E  shows a desiccant membrane plate stack in the prior art that uses a portion of the dehumidified air for indirect evaporative cooling in accordance with one or more embodiments. 
         FIG. 11F  illustrates a section of a desiccant membrane plate stack that uses a portion of the dehumidified air to provide indirect evaporative cooling in a controllable fashion 
         FIG. 11G  shows a close up cut away detail for the bottom of the plate stack in  FIG. 11F . 
         FIG. 11H  illustrates further details of some of the components shown in  FIG. 11F . 
         FIGS. 11I and 11J  show a three dimensional and top view, respectively, of an embodiment that uses a tube structure for exposing liquid desiccant to air streams while providing a simultaneous heating or cooling functions in accordance with one or more embodiments. 
         FIGS. 11K and 11L  illustrate a three dimensional and top view, respectively, of a hexagonal structure for exposing liquid desiccant to an air stream while providing heating or cooling functions in accordance with one or more embodiments. 
         FIG. 12  depicts a complete solar air conditioning system including a solar PV/Thermal array in accordance with one or more embodiments. 
         FIG. 13A  demonstrates how storage and PVT modules can be used to create a hot/cold offset cycle for a desiccant air conditioning system during the day in accordance with one or more embodiments. 
         FIG. 13B  demonstrates how storage and PVT modules can be used to create a hot/cold offset cycle for a desiccant air conditioning system during the night in accordance with one or more embodiments. 
         FIGS. 14A and 14B  show a PV/Thermal module with integrated hot water storage/ballasting system in accordance with one or more embodiments. 
         FIGS. 15A and 15B  show how the ballast tank and storage system can double as a shipping container for the PVT module in accordance with one or more embodiments. 
         FIGS. 16A and 16B  demonstrate how PVT modules and cold sources can be integrated into the wavy plate desiccant system for summer operation in accordance with one or more embodiments. 
         FIGS. 17A and 17B  demonstrate how PVT modules can be integrated into the wavy plate desiccant system and humidifiers for winter operation in accordance with one or more embodiments. 
         FIGS. 18A and 18B  show how the heat from storage or PVT modules can be used during the day and during the night for air conditioning operation in accordance with one or more embodiments. 
         FIG. 19A  shows how a desiccant concentration separator and evaporative cooler can be integrated into the wavy plate system during summer operation in accordance with one or more embodiments. 
         FIG. 19B  shows the system of  FIG. 19A  integrated to a building space wherein the chilled water that is produced by the evaporative cooler is not only used for cooling the conditioner but also used for cooling ceiling panels or floor panels. 
         FIG. 20A  shows how the additional wavy plates in  FIG. 19A  can be used to increase heating capacity during winter operation in accordance with one or more embodiments. 
         FIG. 20B  shows how a portion of the air entering a conditioner can be drawn out of the conditioner and diverted to a third set of wavy plates for winter operation. 
         FIG. 21A  shows a corrosion resistant heat exchanger with thermally conductive plastic plates in accordance with one or more embodiments. 
         FIG. 21B  shows a different embodiment of a corrosion resistant heat exchanger with thermally conductive plastic plates in accordance with one or more embodiments. 
         FIG. 21C  shows the major manufacturing steps involved in using glue structures to construct a fluid to fluid heat exchanger in accordance with one or more embodiments. 
         FIG. 22  shows a water recovery system using plate structures in accordance with one or more embodiments. 
         FIG. 23  shows a desiccant system for heating and dehumidification in accordance with one or more embodiments. 
         FIG. 24A  shows a heating and dehumidification system using the wavy plates and a water recovery system in accordance with one or more embodiments. 
         FIG. 24B  shows a dual effect desiccant regeneration system which uses recovered liquid water for indirect evaporative cooling. 
         FIG. 25  shows a desiccant air conditioning system which captures and condenses combustion gasses and recovers water in accordance with one or more embodiments. 
         FIG. 26  shows a desiccant air conditioning system setup for winter heating that also condenses water vapor and captures contaminants from the combustion process in accordance with one or more embodiments. 
         FIGS. 27A and 27B  show a three-dimensional model of the system of  FIG. 24A  in accordance with one or more embodiments. 
         FIG. 28  shows the water recovery system of  FIG. 22  integrated to a desalination system for water purification in accordance with one or more embodiments. 
     
    
    
     Like reference characters generally denote like parts in the drawings. 
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       FIG. 1A  depicts a liquid desiccant air conditioning system as known in the prior art. A desiccant conditioner  102  contains a liquid desiccant in a bath  104 . The liquid desiccant  104  can be any suitable solution that attracts water vapor from the outdoor air  110  that is blown into the conditioner  102 . The air moves through a filter media  106  that usually comprises a convoluted surface that easily holds and exposes the desiccant to the air stream. Examples of desiccants include CaCl 2  and LiCl 2 . The filter media can be a cellulosic cooling tower fill material. Diluted desiccant  105  that has absorbed water drips from the filter media  106  into the desiccant bath  104 . The spray head  107  distributes the concentrated desiccant evenly across the filter media  106 . Dehumidified and cooled air  111  is directed into the building. A portion (usually around 10%) of the diluted desiccant  112  is brought through a heat exchanger  103  to a regenerator  101 . The majority of the desiccant  112  is brought back to the spray head  107  at the top of the conditioner  102  through an optional cold source  113 . The desiccant that is diverted to the regenerator  101  is heated in an optional heater  114  and pumped to a spray head  107 ′ similar to the spray head on the conditioner side. The heated desiccant falls onto a filter media  106 ′ and drips down  105 ′ into a desiccant bath  104 ′. Return air from the building or outdoor air  108  is brought through the filter media and absorbs water from the desiccant such that moist hot air  109  is exhausted from the regenerator. As discussed earlier, the drawbacks of this system are that the absorption of water vapor into the desiccant is an almost adiabatic process resulting in heating of the air that is meant to be cooled. Furthermore the spray head can lead to some desiccant being carried over into the leaving air streams  111  and  109 . And lastly, the baths  104  and  104 ′ force the air flows  110  and  108  to be horizontal and vertical through the filter media. This makes installation on a building roof more complicated since the exiting air  111  needs to be ducted into a downward direction and the return air  108  from the building needs to be ducted into a horizontal aspect. 
       FIG. 1B  is an alternate system known in the prior art. The conditioner  121  comprises a set of vertical plates  118  (which are constructed to be hollow inside) and a desiccant collector  120 . Chilled heat transfer fluid from a cold source  113  is brought inside the plates  118  and forms a U-shaped loop  116  internal to the plate. A concentrated desiccant  119  is run over the surface of the plates  118 . Outdoor air  110  is directed over the desiccant  119  in a horizontal orientation. The desiccant absorbs water vapor from the air and runs down the surface of the plates  118  into the desiccant collector  120 . The diluted desiccant  121  is pumped through a heat exchanger  103  to the regenerator  122 . The regenerator comprises a set of plates  117  that again are hollow and that have U-shaped channels  116 ′ in them. Diluted desiccant  119 ′ is again run over the surface of the plates  117  that are heated by the hot transfer fluid source  114 . Outdoor air or return air from the building  108  is used to absorb water vapor from the desiccant  119 ′. The desiccant gets more concentrated as it runs down the surface of the regenerator and collects into the desiccant collector  115 . As in the previous example, the air flow in the desiccant system is primarily horizontal resulting in the need for additional ducts to be used for installation on a rooftop. A horizontal air flow would have been preferred because no duct work would have been necessary, but the desiccant collectors  115  and  120  generally block air from flowing vertically. Furthermore, the U-shaped channels do not allow for a counter-flow design between the air, desiccant, and cooling or heating fluids resulting in lower thermal efficiency of both the conditioner and the regenerator. As compared to the system in  FIG. 1A , the liquid desiccant system in  FIG. 1B  uses lower fan power and lower desiccant pump power. 
       FIG. 2A  shows a liquid desiccant system in accordance with one or more embodiments configured for extreme summer operation and so as to integrate with and optional heat pump  201 . A portion of the desiccant in the conditioner  102  is brought through a heat exchanger  202  that can be coupled to a PVT module array. Since the typical desiccant materials that are used are corrosive to metals, the use of a heat exchanger is desirable. This also complicates the integration of the heat pump  201 ; since the desiccant should not contact any metal parts, the heat transfer is made indirectly through a specially designed heat exchanger. As can be seen in the figure, desiccant is taken from the conditioner, is heated in the PVT modules  202  or by the heat pump  201  and sprayed into the regenerator  101 . Conversely concentrated desiccant is taken from the regenerator  101 , run through an optional cold source  203  or through the cold side of the heat pump  201  and into the conditioner. 
     In  FIG. 2B  a similar set up is shown for non-extreme operation. The main difference is that the desiccant from the conditioner is cooled, and put back into the conditioner side rather than also being transported to the regenerator. Desiccant only transfers to the regenerator through the heat exchanger  103 . Similarly the desiccant in the regenerator is only heated and put back into the regenerator itself rather than being put into the conditioner. 
     In extreme winter operation in  FIG. 3A , the heat sources  201  and  202  are now heating the liquid desiccant as it is transported to the conditioner  102 . It is noted that the conditioner in the winter setup is used to add water vapor and heat to in incoming air stream  110  and conditions the air to have a higher temperature and humidity as it enters the building at  111 . It is also possible to add a humidifier  301  that can be preheated by another PVT module array  302  or by another source of thermal energy. Since the water that is brought into the humidifier  301  is not corrosive to metals, it is not per-se necessary to use a heat exchanger in  302 ; the water can be heated directly by the PVT modules. It is further worth noting that the return air  108  from the building generally is higher in temperature and humidity than the outside air  110 . The regenerator  101  in this setup actually captures the heat and moisture from the return air and transports it to the outdoor air, resulting in much lower heating costs and the desiccant system is in this setup effectively functioning as an enthalpy recovery system. 
     In  FIG. 3B  a similar setup is shown as in  FIG. 3A , except now the heat sources  201  and  202  are now used to heat the desiccant on the conditioner  102  side of the system directly. Similarly the cold side of the heat pump  201  can directly draw heat from the desiccant in the regenerator. 
     The cold source  203  in  FIGS. 3A and 3B  will in most cases not be needed during winter operation of the system. It is also noted that the desiccant in winter mode will need to be diluted which means that small amounts of water will need to be added on a regular basis in order to prevent overconcentration of the desiccant. This water can come from the return air from the building, but may still need to be supplemented from other sources. 
       FIG. 4  shows how the enthalpy recovery system from  FIG. 3A  can be integrated into an existing building air conditioner infrastructure. The building space  401  is connected by ducts  402  to the desiccant system from  FIG. 3A . The existing air conditioner heat pump comprising compressor  403  releases heat through fan coil  405  and the incoming air can be supplementally heated by PVT modules  406  and an additional fan coil. The compressed gas expands at the valve  407  and is heated by the return air in fan coil  404  before returning to the compressor  403 . The above described setup significantly reduces the load on the air conditioning system by again recovering both heat and water vapor. 
     In  FIG. 5  a new type of liquid desiccant system is shown. The conditioner  501  comprises a set of plate structures that are internally hollow. Optionally the plate structures can have a wavy shape applied to them. The term wavy as used herein refers broadly to a variety of convoluted structures, including serpentine or undulating shapes. A cold heat transfer fluid is generated in cold source  507  and entered into the plates. Liquid desiccant solution at  514  is brought onto the outer surface of the plates and runs down the outer surface of each of the plates. In some embodiments, the liquid desiccant runs in a wicking surface that significantly increases the area of desiccant exposed to the air stream  503 . In other embodiments—described further below—the liquid desiccant runs behind a thin membrane that is located between the air flow and the surface of the plates. Outside air  503  is now blown through the set of wavy plates. The liquid desiccant on the surface of the plates attracts the water vapor in the air flow and the cooling water inside the plates helps to inhibit the air temperature from rising. The plate structures are constructed in such a fashion as to collect the desiccant near the bottom of each plate thereby eliminating the need for a desiccant collector or bath as was shown in  FIGS. 1A and 1B . The treated air  504  is now put in the building directly without the need for any additional ducts. Furthermore, since all flows of air, heat transfer fluids and desiccant are vertical, the system is thermally more efficient. The wavy shape of the plates has two primary advantages: air is more easily brought in contact with the surface of the plates since the wavy shape constitutes more of a convoluted path than a straight plate would have given. But importantly, the wavy shape allows for the plates to expand sideways without putting undo stresses on the connections for heat transfer fluids and desiccants at the top and bottom of the plates. This is particularly important since the wavy plates should be constructed from a material that is compatible with the desiccant being used, for example from a (thermally conductive) plastic material such as a thermally doped polymer extrusion. Typically such a plastic has a thermal conductance of about 5 to 10 W/mK. As an example thermal conductances for regular plastics range from 0.1 to 0.5 W/mK, whereas copper, aluminum, stainless steel and titanium have a conductance of about 400, 250, 16 and 18 W/mK respectively. Of these materials only Titanium is reasonably suitable for use with desiccants such as CaCl 2  or LiCl 2  due to the corrosive nature of the desiccants. The wavy plates in the regenerator  502  will expand under the higher temperatures for regenerating the desiccant. This can create thermal stresses on the assembly. The wavy shape helps to reduce those stresses by allowing the plates to expand sideways rather than in the vertical direction. 
     The liquid desiccant is collected at the bottom of the wavy plates at  511  and is transported through a heat exchanger  513  to the top of the regenerator to point  515  where the liquid desiccant is distributed across the wavy plates of the regenerator. Return air or optionally outside air  505  is blown across the regenerator plate and water vapor is transported from the liquid desiccant into the leaving air stream  506 . An optional heat source  508  provides the driving force for the regeneration. The hot transfer fluid  510  from the heat source can be put inside the wavy plates of the regenerator similar to the cold heat transfer fluid on the conditioner. Again, the liquid desiccant is collected at the bottom of the wavy plates  502  without the need for either a collection pan or bath so that also on the regenerator the air can be vertical. It should be clear to those skilled in the art that the wavy plates can be easily expanded to add additional cooling or heating capacity, that these plates provide for better heat transfer and that the elimination of any bath or collection pan allows for the system to be directly mounted on a roof opening without the need for additional duct work. An optional heat pump  516  can be used to provide cooling and heating of the liquid desiccant similar to the method employed in  FIG. 1A . It will be clear to those skilled in the art that the absence of a liquid bath or collection pan also enables the easy installation of the conditioner  501  in a remote location from other components in the system, such as are commonly used in what is know as “split” air conditioning systems. 
     It will furthermore be clear to those skilled in the art that the system of  FIG. 5  can be made relative small in size in such a way that the system could be integrated into an automobile or other vehicle. In such an automobile the heat source  508  can potentially be the heat from an engine and cooling could be provided by a Peltier cooling system. 
     In  FIG. 6A  the system of  FIG. 5  is shown in a 3 dimensional projection. Desiccant fluid pumps  601  provide the transportation of the desiccant between the conditioner and the regenerator. The holes  602  at the top of wavy plates  501  and  502  ensure an even distribution of desiccant over the surface of the wavy plates. Groves  603  at the bottom of the wavy plates  501  and  502  collect the desiccant by using either the natural surface adhesion of the desiccant to the plastic of the wavy plates to gather the desiccant into the grove or by using some membrane or other wetting material to help collect the desiccant into the groove. The heat transfer fluid can be connected to the wavy plates at connections  604 ,  605 ,  606  and  607 . 
       FIG. 6B  shows how the inlet air  652  of a set of wavy plates  502  can be made turbulent by a set of plates  651 . The plates  651  are constructed in such a way as to impart turbulent airflow to the air entering the wavy plates  502 . The resulting turbulent air will better exchange heat and moisture with the surface of the wavy plates as compared to air that flows through the wavy plates in laminar fashion. 
       FIG. 7  depicts the system similar to  FIG. 5  with the addition of a post conditioner cooling coil  702  and preheating coil  701  for the regenerator. An alternate configuration for the heat pump  705  is to instead of heating the desiccant as in  FIG. 5 , to heat the heat transfer fluid with heat exchanger coils  703  and  704 . The eliminates the need to have the heat exchanger use corrosion resistant components allowing for a more standard heat exchanger to be used. 
       FIG. 8  shows a close-up view of one embodiment of the wavy plate assembly where the desiccant drain  801  at the bottom of the plates collects the desiccant that has run into the groove  811 . Heat transfer fluid is connected to the plates at  802  and  805 . The main body of the wavy plates  803  can be made from a suitable material that exhibits good thermal conductivity as well as corrosion resistance, for example a thermally conductive plastic extrusion. Liquid desiccant is entered into the distribution channel  806  at the top of the plates  807  and exits the holes  810  at the top of same plates and runs over the surface  804 . The heat transfer fluid  808  runs inside openings  809  in the wavy plates. As can be seen from the figure the construction of the grooves  811  allows the desiccant to collect at the bottom of each individual plate without obstructing the air flow and without the need for a separate common collection pan. It should be obvious to those skilled in the art that the entering air stream  812  and exiting air stream  813  can be reversed and also that the direction of the heat transfer fluid between  802  and  805  can be either upwards or downwards. The desiccant itself would normally run down the surface because of the force of gravity acting on the desiccant. 
       FIG. 9  shows further details of one embodiment of the construction of such wavy plates. A component  901 , which is preferably an injection molded plastic component, is bonded on the thermally conductive extrusion  902 . It should be obvious to those skilled in the art that other manufacturing methods can be employed such as machining, thermoforming, welding and other suitable methods. Other materials for the components can be suitably selected to be compatible with the corrosive nature of typical desiccant solutions, for example Titanium and other noble materials. A similar component  903 , also preferably injection molded, is bonded to the top of component  902 . Desiccant is introduced through inlet  905  and spreads generally evenly through the holes  904 . Heat transfer fluid is transferred through the openings  905  and exists through the openings  907 . Desiccant that has run to the bottom of the wavy plates is collected by taking advantage of surface tension in the liquid into the groove  811  and runs through the drain exit  906 . 
       FIG. 10A  shows an alternative embodiment of a wavy plate construction in which components  1001  and  1002 , which are preferably injection molded, are connected to the top of a wavy plate  1003 . Spreader plates  1013  cause the desiccant and heat transfer fluid to be generally evenly distributed. In one embodiment an additional injection molded component  1004  provides the collection of the heat transfer fluid inside the wavy plate  1003 . A membrane or other suitable material such as a wicking material  1005  is applied over the top of the assembly. An example of such a membrane is hydrophobic Poly Propylene manufactured by Celgard under the tradename EZ2090. An example of a wicking surface is a hydrophilic cardboard sheet material similar to coffee filter paper. The completely mounted assembly  1007  is then connected to a final injection molded component  1006  in such a way that the membrane or wicking material guides the desiccant into the component  1006 . In the final assembly  1008  the liquid channels for the desiccant  1009  and  1012  are shown, as are the channels for the heat transfer fluid  1010  and  1011 . If the material  1005  comprises a membrane, then draining the liquid desiccant from the wavy plates can become a challenge since the top of the assembly can “lock” the desiccant in place (also known as vacuum lock). Holes  1014  are purposely provided to allow air to enter behind the membrane so that the liquid desiccant can easily fill and drain behind the membrane. These holes also keep the membrane from accidentally getting pressurized, which could result in damage or deformation of the membrane. Advantageously, the holes are located slightly above the outlet of the desiccant as can be better seen in  FIG. 11A . It can also be seen in  1008  that two wavy plate assemblies have been joined together to form a small stack of plates. It should be obvious to those skilled in the art that the assembly of wavy plates can so be stacked as to generate any amount of air treatment as desired by simply adding additional plates to the stack. 
       FIG. 10B  shows a detailed cross section of two hydrophobic materials such as membranes  1051  with a hydrophilic wicking material  1052 . Since micro-porous membranes or similar materials are usually made to be hydrophobic, the application of a membrane can have non-uniform wetting caused by the liquid (such as—by way of example—a salt solution or water) to be repelled by the membrane. The repellent forces result in non-uniform flow of liquid on the back of the membrane. By using a hydrophilic material  1052 , the wicking effect of the hydrophilic material causes the liquid to evenly distribute behind the membrane resulting in significantly increased evaporation through the membrane and a significantly increased active area. A liquid running inside the wicking material will spread uniformly between the two membranes. 
       FIG. 10C  shows a hydrophilic material  1052  behind a hydrophobic material such as a membrane  1051 , attached to a thermally conductive support wall  1053  (which can be, e.g., a wavy plate). If the support wall is also hydrophobic such as is often the case with plastics and the like, then the wicking material will ensure even flow distribution of the liquid. The support wall can be made to be thermally conductive which would allow one to adjust the temperature of the liquid inside the wicking material and thereby control the evaporation of absorption through the membrane. 
       FIG. 10D  shows a similar structure as in  FIG. 10C  wherein the wicking material is applied on both sides of the (thermally conductive) support wall  1053 . The liquids inside the wetting materials  1052  on each side of the wall can now be made to be different. For example, the leftmost wicking material could be wetted with a salt solution and the rightmost wicking material could be wetted with water or some other heat transfer fluid. 
       FIG. 10E  shows a structure similar to  FIG. 10D  wherein the support wall  1053  is now made to be hollow such that a heat transfer liquid  1054  can be used inside the support wall. Such a structure allows heat transfer from the heat transfer fluid  1054  through the walls into the wicking materials  1052  on either side of the wall  1054 . It should be obvious to those skilled in the art that other combinations of hydrophobic and hydrophilic materials can be devised. 
       FIG. 11A  depicts additional details of the construction of such as stack of wavy plates. A stack of wavy plates  1101  can be set up to treat air multiple times by stacking the plates vertically as well as horizontally. Vertical stacking allows air to be treated for instance to increase dehumidification, whereas horizontal stacking increases the overall capacity of treated air. Detail  1102  shows a detail of the bottom of the wavy plate construction in which the membrane or wicking surface  1005  is used to guide the desiccant into the bottom drain  1006 . The lower edge  1111  of the membrane or wicking material is not fixedly connected so as to avoid potential pressure buildup of desiccant which could lead to damage of the membrane or wicking surface. Detail  1107  shows the same area as detail  1102  except with the membrane  1005  removed. The channels  1109  and  1110  that are created in the components  1004 ,  1006  and  1003  allow for the membrane  1005  to be bonded, but still allow for the desiccant to pass through the channels. Similarly detail  1103  of the top of the wavy plate assembly shows how the desiccant is able to enter through supply channel  1012  and run through the channels in components  1002  and over the surface of wavy plate component  1003 . It should be clear from the details that the holes  1014  and the unconnected edge  1111  at the bottom advantageously serve the function to 1) inhibit vapor lock at the top of the assembly and 2) to avoid pressure damage to the membrane or wicking surface at either the top or the bottom of the assembly. Again detail  1108  shows the same top assembly with the membrane  1005  removed. Since the surface area of the wavy plate assembly  1101  is important for the overall air treatment capacity of the system, it should be easy to stack multiple wavy plates in both the horizontal and vertical direction as discussed above. Features  1104 ,  1105  and  1106  allow for stacking of plates by aligning and locking plates together. It should be clear to those skilled in the art that such features can have many shapes and sizes. 
       FIG. 11B  shows a system setup similar to  FIG. 5  wherein the wavy plates are accepting a horizontal air flow. In the figure the wavy plates form two stacks in such a way as to treat the air passing through twice. By placing the wavy plates at a small angle to the incident air, the air will interact more readily with the liquid desiccant on the surface of the wavy plate. Such liquid desiccant can be located behind a membrane or in a wetting material as described before. By maintaining the wavy aspect in the vertical direction, any thermal stresses caused by thermal expansion and contraction of the wavy plates are significantly reduced. 
       FIG. 11C  illustrates the setup from  FIG. 11B  in a top-down view. 
       FIG. 11D  shows the dual set of wavy plates from  FIG. 11B  implemented twice. The first set treats air coming from outdoors and performs a double treatment of this incoming air. The second set receives return air from a space and also treats it twice. In such a setup the recovery of energy (water vapor and thermal energy) can be near complete. This setup allows for energy recovery while still allowing thermal energy to be added or removed and water to be added to air coming through the plate system through the desiccant, thereby enhancing the heating or cooling of the incoming air. Conventional energy recovery systems typically do not allow for the addition or removal of thermal energy or water. 
       FIG. 11E  illustrates a desiccant cooling system in the prior art. A stack of plates  1134  is placed (typically about 0.25 inch apart) and is covered by a membrane  1131  that has water  1133  flowing behind it. The opposite site of the plate contains a second membrane  1135  behind which a liquid desiccant is flowing. Incoming air  1136  is dehumidified because water vapor in the air is absorbed into the liquid desiccant through the membrane  1135 . At the exit of the plates, the dehumidified air  1137  is partially directed towards the space being cooled and a portion is directed in the reverse direction  1138 . This secondary air flow  1138  is relatively dry and can effectively absorb water vapor from the water  1132  behind the membrane  1135 . The absorption of water vapor through the membrane into the air leads to a cooling effect of the diverted air. This cool air in turn cools the water  1133 . The cool water then thermally cools the plates as well as the liquid desiccant which ultimately leads to the main air stream being cooled. This approach allows evaporative cooling to occur in climates such as Miami, Fla. where humidity levels and temperatures are relatively high so that cooling towers normally do not function as well. By first drying the incoming air and then using indirect evaporative cooling through the membrane, the system is able to use evaporation to create a cooling effect. To inhibit the secondary air from mixing with the outdoor air, it is diverted by diverter  1139  near the end of the plate stack in a direction  1140  perpendicular to the drawing. As can be seen in the figure, the membrane/liquid layers are mirrored—water is facing water and desiccant needs to face desiccant for each of the plates. This creates a challenge for manufacturing such a plate stack. 
       FIG. 11F  illustrates an embodiment of the concept of  FIG. 11E  wherein wavy plates  1147  are used to provide and alternating structure for liquid desiccant and water. In some embodiments, the wavy plates are made using thermally conductive plastics. The wavy plates contain ridges  1146  to support the membranes  1131  and  1135 . Liquid desiccant enters the wavy plate set through channel  1141  and exists through channel  1144 . Water enters through channel  1142  and exits through channel  1143 . An adjustably connected air diverter  1145  takes a controllable amount of air in directs it in the reverse direction  1138 . The diverted air  1138  absorbs water from behind the membrane  1135 . The diverter  1139  closes the top of the opening between the plates and directs the airflow  1140  in a perpendicular direction. The bottoms and tops of the wavy plates  1147  are inserted into an injection molded component  1006  similar in design to  FIG. 10A . 
       FIG. 11G  shows a detail of  FIG. 11F  wherein a close-up of the wavy plates  1147  that have the membranes  1131  and  1135  mounted to the ridges  1146  on the wavy plates. In order to provide liquid to opposite faces of the wavy plates, holes  1150  and  1151  are provided in such as way is to provide access to alternating sides of the wavy plates  1147 . The liquid desiccant enters the drain channel  1144  through the holes  1152 . As can be seen from the figure, the wavy plates  1147  can be made to be generally identical, except that the wavy plates are flipped upside down in an alternating fashion. 
       FIG. 11H  shows a detail of the wavy plates  1147 . The wavy plates are alternatively flipped upside down to provide opposing connections to the water and desiccant supply lines. As can be seen in the figure, the ridges  1146  provide support for the membrane and the thermally conductive surface  1134  provides a thermally conductive path to the opposite side of the wavy plate. The holes  1153  provide a uniform distribution of the liquids similar to the holes in component  1013  in  FIG. 10A . 
     In various embodiments described herein, wavy plate structures are used to expose a liquid desiccant to an air stream through a membrane while simultaneously exposing the liquid desiccant to a heat transfer fluid. Various alternate structures can also be used to perform these functions. For example,  FIGS. 11I and 11J  illustrate a tubular structure for exposing a liquid desiccant to an air stream through a membrane while simultaneously exposing the liquid desiccant to a heat transfer fluid. The structure comprises a plurality of tubes  1181  that can be made from any suitable thermally conductive material for example from a thermally doped polymer extrusion. The inner wall of the tube can feature ridges  1184  to allow a membrane  1182  to be bonded to the top of the ridges in such a way that the membrane is held at a small distance to the tube wall so that liquid desiccant can pass between the wall and the membrane perpendicular to the plane of the figure in the so created channel  1183 . Air can thus be passed in the center of the tubes  1186 , while heat transfer liquid can pass in the generally triangular sections  1185  between tubes. The heat transfer fluid is thus able to heat the desiccant solution through the thermally conductive walls. It should be understood that other shapes and arrangements of tubular structures can also be devised.  FIGS. 11I and 11J  also show that it would be possible to apply some wavy shape to the tube which as in the previous embodiment functions to achieve better interaction between air and desiccant while at the same time reducing stresses due to thermal expansion in the vertical direction of the structure. 
       FIG. 11L  is a top view of an alternate hexagonal structure of thermally conductive surfaces  1192  in accordance with one or more embodiments.  FIG. 11K  is a three-dimensional view of one of the hexagonal elements forming the hexagonal structure. Each hexagonal element in the structure includes thermally conductive surfaces  1192 . Ridges  1194  allow membranes  1191  to be mounted substantially parallel to the thermally conductive surfaces. The channels between the membrane  1191  and the walls  1192  in some of the elements can be used for passage of a heat transfer liquid or alternately for passage of water to perform an evaporative cooling function in a similar manner to the system described in  FIG. 11E . In the example shown in  FIG. 11L , the hexagonal elements with channels between the membrane  1191  and the walls  1192  shaded in gray contain water, and the channels in the other hexagonal elements contain liquid desiccant. Thus, air in channels  1195  can be exposed to the liquid desiccant through the membranes, while already treated air  1196  can be exposed to water through the membranes. 
       FIG. 12  shows how the wavy plate assemblies discussed above can be integrated into a full solar air conditioning system. The enclosure  1201  provides protection of the desiccant air components from the weather. The system includes the conditioner  501  and the regenerator  502 . Pumps  601  provide desiccant flow to the conditioner and regenerator. Blowers  1209  move air into and out of the building. Outdoor air  503  is treated by the wavy plates and moved into the building as treated air  504 . Return air  505  from the building can absorb the heat and water vapor and is exhausted at  506 . A small optional chiller  1203  provides sensible cooling if needed. A solar inverter  1202  can invert the electricity coming from a series of solar modules  1205 . There is a significant advantage for integrating a solar inverter to an air conditioning system (whether it is a conventional air conditioner or a desiccant air conditioner): a rooftop air conditioning unit already has a significant electrical supply line going up to it. By integrating an inverter into a replacement air conditioning unit, the installation of PV or PVT modules a dramatically simplified. Normally a solar inverter is located somewhere inside the building and electrical lines are run from the roof to the inverter creating a significant amount of cost and labor. By locating a solar inverter inside an air conditioner there is no need to run any electrical cabling into the building, since the existing electrical lines to the air conditioner can be back-fed by the inverter to supply electrical power to the building. Also in the figure is shown a supplemental water heater  1204  that can be used when the PV-Thermal modules do not provide adequate temperatures or power. In addition the solar modules  1205  can have a water storage tank  1206  in such a way that access hot water can easily be stored. In this system the hot water tank  1206  is functions to provide ballast to the PVT module. Normally a concrete block or similar ballast would be provided to hold down solar modules on a flat roof. However, by using a thin flat tank like  1206 , we achieve two objectives: hot water storage as well as ballast. It should further be noted that each solar module can have its own storage tank. By integrating tanks  1206  below the PVT modules  1205 , all electrical lines  1207  and heat transfer fluid lines  1208  can be led to the desiccant system  1200  without the need for any lines entering the building or for installing tanks or inverters anywhere in the building thereby significantly improving installation time for the system. 
       FIG. 13A  illustrates how such a storage system as shown in the previous figure can be used. At the start of the day,  1301  the PVT modules  1304  start receiving solar radiation  1306 . The storage tanks  1305  underneath the PVT modules are generally filled with cold water (or some other heat transfer fluid). The PVT modules start generating hot water which is directed to the solar air conditioning system  1200 , and specifically to the regenerator  1310 . Since sensible cooling also needs to be provided, one of the cold water tanks is connected to the conditioner  1309 . As the day progresses  1302 , the PVT modules will generate excess hot water which can be used to start filling up some of the tanks. The connection  1307  and  1308  are made in such a way that the correct number of tanks is connected to the air conditioner  1200 . At the end of the day  1303 , most or all of the tanks will contain hot water. This hot water can now be used to continue to run the regenerator during the evening and night by connecting the hot tanks through lines  1316  to the regenerator as shown in  FIG. 13B . Since PVT modules are also relatively efficient at shedding heat by radiation  1314 , the PVT modules can now be directly connected to the conditioner by lines  1315 . In the middle of the night  1312 , the radiation from the PVT modules can be used to start making cold water for storage in the tanks in such a way that by the end of the night all hot water has been used and cold water has filled the tanks underneath the modules. This allows the cycle to start over again. Effectively this arrangement allows the day to night shifting of cold and hot water generation, which can eliminate the need for any sensible cooling system such as the small chiller  1203  in  FIG. 12 . 
       FIG. 14A  shows an embodiment of the solar PVT modules from  FIG. 12  in some level of detail. The PV laminate  1401 , which can either be silicon or thin film based, generates the electrical power. The storage tank  1402  doubles as a hot liquid storage container as well as a ballasting system.  FIG. 14B  shows a cut-out close-up of the system. A series of thin channels  1405  behind the laminate  1401  collect heat from the laminate and heats the transfer fluid. The main hot water channel  1404  brings water down to a thermostatic valve assembly  1403 . The thermostatic valve can direct hot water either directly to the main manifold  1406  or to the storage tank  1402 . The thermostatic valve can either be operated automatically or through a software control. 
       FIGS. 15A and 15B  demonstrate another use of the storage tank underneath the PVT module. The storage tank is this case has a removable lid  1501  and a main body  1502 . The side and rear supports  1504  of the PV laminate  1503  are removably connected to the tank and the PV laminate. After removing the lid  1501 , the entire solar module and support structure can be put inside the tank body thereby protecting the solar module during shipment. This alternate use of the tank as a shipping container can be very helpful when solar modules have to be setup and disassembled on a regular basis for example as may occur for remote military basis. In effect, the tank now serves three functions: shipping container, storage tank and ballast system. 
       FIG. 16A  demonstrates a schematic of the setup of a solar air conditioning integrated to a desiccant system for extreme summer operation. All of the desiccant from the conditioner  501  is sent to the regenerator  502 . The advantage of the plate structures is that in effect the plate sets  501  and  502  are three way heat exchangers between air, liquid desiccant and a heat transfer fluid. This allows for PVT modules to be tied in at two places: directly heating the heat transfer fluid at  1601 , or heating the desiccant through a heat exchanger at  1602 . Similarly the cold connections for sensible cooling can either be made on the desiccant side  1604  or on the heat transfer fluid side  1603 . 
       FIG. 16B  shows a setup for summer non-extreme operation. The major difference with the previous case is that only a portion of the desiccant is send through the heat exchanger  513 . The flows of desiccant at  1609  and  1610  can be adjusted so that only a portion of the desiccant is send to the regenerator. As in the previous case, the PVT modules can be tied in at two places: at the desiccant side  1606  and at the heat transfer fluid side  1605 . Again the cold connections can be made on either the desiccant  1608  or the heat transfer fluid  1607 . It will be clear to those skilled in the art that all the heat sources and cold sources can be supplemented by other sources tied into the same lines in parallel or in series to the PVT modules or cold sources in the drawings. 
       FIG. 17A  shows a liquid desiccant system set up for winter heating in extreme conditions. Since active cooling of the leaving air is not necessary, the cold sources have been omitted from the drawings. Again PVT modules can be tied into desiccant side  1705  or the heat transfer fluid side  1706 . Since the heated desiccant will also emit water vapor additional water may have to be added at  1707  to prevent high concentrations of desiccant and potential crystallization of the desiccant salts. Furthermore the treated air  504  may require additional humidification  1703  which again can be done more efficiently by preheating the water at  1704  with PVT modules or another heat source. 
       FIG. 17B  shows a similar setup to  FIG. 17A  except for non-extreme winter conditions whereby only a portion of the desiccant is send through the heat exchanger at  1708  and  1709 . 
       FIG. 18A  shows how the PVT module array from  FIG. 13A  can be connected to the liquid desiccant system. PVT modules  1804  receive heat and the hot heat transfer fluid is send to both the desiccant regenerator  502  and the hot storage system  1803 . The cold side can draw cold water from the cold storage tanks  1805 . At night,  FIG. 18B  shows how the regenerator is now drawing from the hot storage tanks  1803  whereas the conditioner is radiating heat through the PVT modules  1804 , which at the same tank provide cool water in the cold storage tanks  1805 . 
     The setup from  FIGS. 18A and 18B  works well when there is a large temperature difference between night and day temperatures, e.g., as is the case in desert or in the central valley in California. However in other climates the temperature may not chance as much and additional sensible cooling can still be required. As discussed before such sensible cooling can be provided with a small chiller or a heat pump. It should be clear to those skilled in the art that other means of cooling such as Peltier cooling or evaporative cooling could be employed. In climates such as Miami, Fla. evaporative cooling is not as effective in the summer due to the already high humidity levels. 
       FIG. 19A  shows an alternative method for cooling that uses a portion of the dehumidified air  504  and directs it to a third set of plate structures  1904 . The diverted air flow  1903  is already treated and low in humidity. Instead of desiccant, the third set of plate structures has water running over its surface and behind a membrane or wicking surface, and has a heat transfer fluid internally to the plates  1907 . The diverted air is now directed between the wavy plates in effect creating what is known as an evaporative chiller using the wavy plates. Water is supplied to the third set of plate structures at  1905  and un-evaporated water is returned to the top of the plates through line  1909 . The portion of air  1903  that is diverted can be adjusted with louvers or baffles or some other suitable mechanism in such a way that the amount of air is variable. Varying the amount of air will regulate the temperature achieved in the building by the entering air  504 . As in  FIG. 18B , PVT modules  1807  can be used at night to enhance the cooling effect and cold water can be stored in tanks  1805 . It would also be conceivable to locate the third set of plate structures  1904  (partially) underneath the conditioner  501 . This will increase the height of the overall stack, but negates the need to redirect the air  504  in the opposite direction. Conversely it would also be possible to divert the air  504  out of the plane of the drawing and into the third set of wavy plates in a horizontal flow pattern. Locating the third set of wavy plates underneath the conditioner plates  501 , has as a disadvantage that reversing the air flow for winter operation such as is shown in  FIG. 20A  becomes impossible. However, drawing a portion of the air  504  out perpendicular to the plane of the drawing and sending it through the third set of wavy plates  1904  in a horizontal fashion, still will allow the air in the third set of plates to be used for winter heating as is shown in  FIG. 20B . 
     In addition to the third set of plates,  FIG. 19A  shows another improvement to the desiccant system. Desiccant storage system  1902  uses the fact that dilute desiccant will physically separate from concentrated desiccant if flow rates are low and the desiccant has sufficient time to settle. In other words if left alone the concentration in tank  1902  will tend to increase going from the top to the bottom. One can take advantage of this effect by connecting the desiccant lines at the appropriate heights along the sides of the tank. One can also draw the desiccant from a variable height in the tank using a vertically adjustable drain  1908 . By moving the drain  1908  up, the system will drawer lower concentration desiccant resulting in less dehumidification. In effect this gives the system a control capability for humidity in the building. Lowering the drain  1908  will decrease the humidity in the building but will also result in higher costs for the regeneration. In effect this now gives the system independent control over temperature of the air by adjusting the supplemental heating system  1901  is used when the PVT modules  1804  do not generate adequate heat. 
     It should be understood that various features and elements (such as, e.g., the tank  1902 ) described in connection with particular embodiments, can also be implemented in other embodiments though not explicitly indicated. 
       FIG. 19B  shows the system of  FIG. 19A  wherein the third set of wavy plates  1904  that function to provide chilled water to the conditioner  501  are now also providing chilled water  1956  to one or more ceiling panels  1955 , a so-called “chilled ceiling”. This approach allows the chilled water produced in the third set of plates to also provide sensible space cooling in an integrated approach. The cooled and dried air  504  and  1952  is typically guided through a series of ducts  1953  and delivered to the space  1954  in the building  1951 . This approach allows for easily balancing of the buildings requirements for latent and sensible cooling by varying the number of plates in the plate sets and by adjusting the desiccant concentration which in turn affects the humidity in the space. It should be clear to those skilled in the art that in stead of chilled ceiling plates a series of fan coils or other suitable liquid to air heat exchangers could be deployed. 
       FIG. 20A  shows the system from  FIG. 19A  but set up for winter heating. Since oftentimes the heating capacity in the winter needs to be much larger than the cooling capacity in the summer, it is now possible to use the third set of wavy plates as part of the heating of the incoming air. Instead of flowing water over the surface of the third set of plates, the system is now using the liquid desiccant to treat the air. In winter mode the supplemental heater  1901  does not need to be used and neither does heat need to applied to the heat transfer fluid in loop  2001 . In stead the supplemental heater  2003  can be used to heat the heat transfer fluid in the conditioner wavy plate sets  501  and  1904 . Additional pre-heater coils  2006  can be used to heat the entering air  503  and  1906 . The desiccant  2002  that enters the regenerator  502  is picking up heat and water vapor from the leaving air  505 . As discussed for  FIG. 17A , this serves to reduce the heating requirements for the conditioner as the desiccant through piping  2004  transports this heat and water to the conditioners. Lines  2005  now connect the desiccant to also reach the third set of wavy plates. As winter conditions oftentimes require humidification to occur, additional water can be added through either the same system  1905  that is used for evaporative cooling in summer mode or by additional humidifiers  1703 . 
       FIG. 20B  shows how the air  2051  flows in substantially a vertical direction through the third set of plates  1904  during winter heating pushed by the fan  2053 . During summer cooling the air  504  is directed out of the plane of the drawing following the arrow  2052  and directed into a substantially horizontal flow direction by the fan  2054  which is substantially located behind the plane of the drawing and behind the third set of wavy plates  1904 . The advantage of this approach over the approach described in  FIG. 20A  is that there is no need for a reversible air fan: instead a winter fan  2503  is used during heating season and a summer fan  2504  is used during cooling season. The fan  2505  on the conditioner is always directing air in the same vertical flow. A further advantage of this approach, besides the increase in winter heating capacity is that the entire area of the third set of plates is actively used in both winter and summer. The approach described in  FIG. 11E  has as a disadvantage 1) that is not reversible for winter heating support, 2) that the effective area, particularly for the water channels  1138  is reduced due to the manner in which air flows through the evaporative channel  1138 , and 3) that the ratio of evaporative channels  1138  over desiccant channels  1137  is fixed, giving less flexibility to adopt the system to climates where maybe less evaporation is needed (sensible cooling) and more dehumidification (latent cooling). By separating the evaporative channels into a third set of plates, the flexibility is increased to adopt the system to various climate conditions. 
       FIG. 21A  depicts a plate heat exchanger in accordance with one or more embodiments. Since the desiccants used in these air conditioning systems are typically corrosive to metals, normal heat exchanger—which is typically constructed with metal—can not easily be used unless materials have been selected specifically for corrosive duty, which usually has a negative impact on cost. By using a flat plate construction wherein the entire units is made out of plastics, costs can typically be reduced. Desiccant enters the heat exchanger in two places, for example, hot desiccant enters at  2101  and exits as cold desiccant at  2103 , and cold desiccant enters at  2102  and leaves as hot desiccant at  2104 . The housing  2105  contains a plate  2106  assembly that has thermally conductive surfaces  2110 . Obstructions  2109  inside the plates  2106  create a long convoluted path for the desiccant. Vertical separators  2107  create a long convoluted path for the fluid flowing in the opposite direction to the fluid inside the plates. Cutouts  2108  in the vertical separators  2107  force the opposing fluid into an up-down and left-right direction. It will be clear to those skilled in the art that other construction approaches of thermally conductive flat plastic plates can be used as a heat exchanger. 
       FIG. 21B  shows an alternative arrangement of thermally conductive plastic plates for a heat exchanger. The heat exchanger  2150  comprises a stack of formed, thermally conductive plastic plates  2155  and  2157 . Cold liquid enters at  2151  and is heated through the plate assembly and exits as hot liquid at  2152 . Hot liquid enters at  2153  and exits cold at  2154 . Each of the plates contains a seal  2156  that is oriented in such a way the even plates  2155  allow for flow from lower left to upper right of the plates  2155  and odd numbered plates  2157  have a mirror image seal  2156 ′ that allows flow from the lower right to the upper left. The turbulence ridges  2158  cause the liquid flow to go up and down when it moves from the inlet to the outlet, thereby creating better heat exchange with the liquid in the next channel. The turbulence ridges can be created by forming them into the plastic plate  2155  and  2157  such as for example by thermoforming or casting the plastic. Alternatively, since the molding costs of forming plastics plates are substantial, it is possible to using a glue system to attached glue lines  2158  to the plates  2155  and  2157 . Such glue lines can be formed by a simple XY robotic gluing system for example using 3M Corporation&#39;s Marine 5200 Polyurethane glue. The sealant lines  2156  and  2156 ′ can also be formed using the same gluing system, except that the height of the sealant lines would be made about 2× the height of the turbulence lines  2155  and  2157 , in such as way as that when the plates are stacked the glue lines support each other and the seal lines cover the distance between the top and bottom plates. 
       FIG. 21C  is a cross section schematic view of the plate structure and exemplary manufacturing steps involved in using glue structures to construct a fluid to fluid heat exchanger as was shown in  FIG. 21B . As shown in  FIG. 21C , in step A, a plate  2155  preferably made from a thermally conductive, non-corrosive material is first placed in a machine that can evenly apply glue ridges  2158  in a pre-determined pattern on one side of the plate. After the glue ridges are cured (step B), the plate is flipped over and a second set of glue ridges  2158  is applied to the opposite side of the plate (step C), in a similar or different pattern. A number of similar plates are thus constructed in this fashion. After the number of plates have cured (step D), a base  2161  of the heat exchanger is positioned and a glue pattern  2156  meant for sealing to the base is applied. Before curing can occur, the first plate  2155  is placed on the seal in such a way as to adhere to the underside of the first plate (step E). This process step is repeated with the other plates (step F). Finally, the top plate  2162  is placed with a glue seal  2156 ′ (step G). The advantage of this construction process is that it is very easy to make heat exchanger units with different materials, plastics as well as metals, with virtually no setup or tooling costs. Furthermore, one can easily change the size of the heat exchanger by simply enlarging the plates and re-programming the glue machine. Traditional heat exchangers typically use formed metal plates and thus every size change can require a new die for forming the metal. These heat exchangers also often employ a cast urethane gasket, so changing sizes also will often require a new casting mold. 
     In certain situations it could be desirable to capture the water vapor in outdoor air and turn it into liquid water, for example, to generate drinking water.  FIG. 22  shows an arrangement whereby two sets wavy plates have been integrated into an enclosure  2201 . A first wavy plate set  2202  has—as before—a hot heat transfer liquid generated by a heat source  2211 . Desiccant from a source  2203  is directed to the surface of the wavy plates  2201 . The heat from the source  2203  causes water vapor to evolve from desiccant on the surface of the wavy plates. Air  2205  that is driven between the plates by the fan  2206  absorbs the water vapor and is moved to the right side of the system. Since the complete system is enclosed and the air is unable to escape, the relative humidity in the enclosure  2201  will reach close to 100%. When the heated, moist air  2205  exits from the first set of wavy plates, it will be close to saturation. When that same air reaches the second set of wavy plates  2207 , the cold water loop  2208  causes the water vapor to condense on the surface of the wavy plates  2207  and is then collected at the bottom of the wavy plates  2207  in the form of liquid water that flows out of the system at  2210 . The cooler air  2204  exits the bottom of the wavy plates  2207  and is transported back to the first set of wavy plates  2202 , where it is heated again and where it absorbs water vapor from the desiccant, which starts the cycle over again. It is possible to add a vacuum pump  2209  so as to operate the system of  FIG. 22  at reduced pressure. This would lower the required temperature to evolve water vapor from the desiccant on the first wavy plate set  2202 , but would make the system more complicated, for example one would also have to add a pump mechanism to retrieve the condensed water from the system at outlet  2210  and to prevent the backflow of the desiccant on the first set of wavy plates  2202 . An optional air to air heat exchanger  2212  could be added, but that could lead to condensation in the heat exchanger, which would be more difficult to recover. It should be clear to those skilled in the art that the condensation in the wavy plates  2207  could be accomplished in other was such as a set of metal plates that are relatively cool as compared to the wavy plates  2202 . Since there is no desiccant involved in the condensation process, any suitable material such as metal plates can be used for the condensing component. 
       FIG. 23  shows a system that uses a liquid desiccant for the dehumidification of greenhouses. Conditioners  2322  and  2323  contain liquid desiccant conditioners as shown also in  FIGS. 1A and 1B . The spray heads  2314  spray desiccant into a cooling tower fill  2315 , which dehumidifies the greenhouse air  2317 . Diluted desiccant  2316  rains down into a collection bath  2318 . Some of the desiccant  2324  is pumped through the heat exchanger  2320  and reaches a regenerator  2301 . The desiccant can be optionally heated by a PVT module heat source  2319  before reaching the desiccant collector  2304  that is part of the regenerator. Some of the concentrated desiccant in the collector  2304  is pumped to a heat exchanger  2306  and/or through an optional PVT module heating system  2305  before being sprayed into a filter material  2303 . The filter material  2303  is able to spread the desiccant over a large area while letting air through. Air  2302  is pumped by the fan  2309  through the filter material and picks up water vapor from the hot desiccant. The hot moist air is then transported to the other side of the regenerator where cold water is sprayed into the air at  2321 . Water condenses from the air and collects into a collection bath  2310 . Some of the water is pumped through lines  2312  to heat exchangers  2313  where the water is cooled by the air stream coming through the conditioners  2322  and  2323 . Excess water is drained at  2311 . The heat for the system is provided by water heater  2308  or optionally by the PVT modules  2307 . The heat exchanger  2306  is needed because the corrosion of the desiccant does not allow direct heating by the water heater. 
       FIG. 24A  shows a significantly more efficient water generation system. The wavy plate conditioner  2405  treats the entering air  2406  and absorbs moisture as before into a desiccant running over the surface of the wavy plates. The leaving air  2407  is warmer and dryer than the entering air  2406 . Diluted desiccant is pumped through a heat exchanger  2404  and through an optional PVT module heater  2403  to the water recovery system  2200  discussed above. Since the wavy plates in effect comprise a three way heat exchanger, the system  2400  can be much simpler. Water heater  2402  and optional PVT modules  2401  heat a heat transfer fluid  2409  which runs through the wavy plates inside the water recovery system  2200  without the need for a heat exchanger. Similarly, cooling liquid in  2408  can run directly through the conditioner wavy plates  2405  without an additional heat exchanger. This simpler system is also more energy efficient since the air flow in the conditioner is less obstructed and since the heating and cooling in the wavy plates is done in-situ. As a result a lower temperature heat source such as the PVT modules can be used. Water is recovered again at  2410 . 
     The regeneration of dilute liquid desiccant should preferably be performed at high efficiency as well as at low temperature. Multiple effect regenerations are known in the art that have high efficiency, but generally also require high temperatures. High regeneration temperatures make it difficult or impossible to use “waste” energy sources or solar energy sources. Generally speaking lower temperature waste energy is more readily and cheaply available than high temperature waste energy.  FIG. 24B  shows a combination of the water recovery system from  FIG. 22  and the indirect cooling system of  FIG. 19A . By combining the water recovery system  2200  into the regenerator plate set  502 , the regeneration of desiccant becomes what is known as a multiple effect regenerator. The dilute desiccant  511  is first directed to the plates inside the water recovery system  2200 . Inside the wavy plates hot water  2409  is provided to evaporate water from the liquid desiccant. The liquid desiccant exits at the water generator at higher concentration and is directed to the plates at  515 . Hot water vapor inside the water generator  2200  heats the water loop  2408  which in turn heats the wavy plates  502  of the regenerator. Concentrated desiccant  512  is then returned through the heat exchanger  513  to be reused in the conditioner. One advantage of this system is that it can regenerate at higher efficiencies than a single effect regenerator, while still operating at lower temperatures. Furthermore the recovered water  2410  can be directed through water line  2451  and optional cooler  2452  to the evaporative section of the indirect cooling system from  FIG. 19A , thereby reducing or even eliminating the need to provide a water supply source. 
       FIG. 25  shows the system of  FIG. 24A  with some additional improvements. Rather than sending all of the desiccant to the regenerator  2200 , the separator  2501  allows for the least concentrated desiccant near the top of the separator to be sent for regeneration and the most concentrated desiccant to be used again in the conditioner. Combustion of fossil fuels generally results in carbon dioxide and water vapor being produced. Other combustion byproducts are contaminants such as NO x  and SO x  and other residual by products. Gas burner  2502  produces these gasses if it is used in the space to be treated such as inside a greenhouse. Hot water coils  2503  absorb most of the heat generated by the burner. The hot water is used in the regenerator  2200 . Water vapor, CO2 and the contaminants such as NO x  and SO x  go through the hot water coils and enter the wavy plates  2405 . The CO2 is desired in the greenhouse, but water vapor and other contaminants are not. In effect the wavy plates function as what is known as a condensing boiler by absorbing the water in the combustion exhaust, which releases additional heat and makes the overall combustion process more efficient. But unlike a condensing boiler the desiccant is also able to absorb some of the contamination in the burner effluents. The desiccant transports these contaminants with the water to the regenerator  2200  where supplemental filters  2411  can be employed to filter these contaminants out of the desiccant or out of the air stream in the regenerator. The arrangement in  FIG. 25  allows for burning of fuels such as biogases that are not as clean burning as natural gas. Also shown in the figure is an additional external cooling cool  2504  that can be added to aid in the condensation of the water. 
       FIG. 26  shows how some of the concepts discussed in the previous figure can also be integrated into winter heating system as discussed in  FIG. 17 . Water heater  2602  uses a gas burner  2601 . The heated water  2604  can also be heated by the PVT modules  1706  to heat the conditioner  501 . Desiccant on the surface of the regenerator  501  absorbs water vapor and other contaminants such as NO x  and SO x  and other residual by products. The desiccant is transported to the water recovery system  2200  through optional filters  2603  that can capture some of the contaminants in the desiccant. Recovered water at  2608  can be drained off or can be diverted to a humidifier  1703  through lines  2609 , which can optionally be preheated by PVT modules  1704  or some other heat source. The cold loop for the condensation of water in the regenerator  2200  can be cooled by an external cooling coil  2607 , but can also be cooled by running water to the wavy plates  502  by the lines  2606 . 
       FIGS. 27A and 27B  show three dimensional views of the desiccant system from  FIG. 24A  set up for greenhouse heating.  FIG. 27A  shows the enclosure  2701  containing the desiccant conditioner wavy plates  2405 . Fans  2701  can move the air through the desiccant conditioner.  FIG. 27B  shows a rear view of the same system with some openings provided to illustrate the internal components. The regenerator plates  2202  receive hot water from the water heater  2402 . Heat exchanger  2404  separates the hot and cold desiccants. Condenser plates  2207  collect the water from the system. 
       FIG. 28  shows how the water generator  2200  can be used in a desalination system. Seawater  2803  is guided between a set of membranes  2801  that have concentrated desiccant  2804  on the opposite side. The desiccant functions as a draw fluid attracting water  2802  through the membrane into the desiccant, thereby diluting the desiccant. An optional set of PVT modules  2806  can preheat some of the desiccant. The diluted desiccant is now guided through the heat exchanger  2811  to the regenerator  2200 . A heating system  2807  heats a heat transfer fluid that is used in the regenerator wavy plates  2813 . The heat transfer fluid can also be heated by the PVT modules  2812 . The desiccant can also be heated by the PVT modules  2810 . An external cooling loop  2808  can be employed to cool the condenser plates  2814 . Pure water is recovered at point  2809 . The advantage if the described system is that it can operate at significantly lower power levels than desalination systems that use osmosis, since solution pump power can be kept very low. 
     Having thus described several illustrative embodiments, it is to be appreciated that various alterations, modifications, and improvements will readily occur to those skilled in the art. Such alterations, modifications, and improvements are intended to form a part of this disclosure, and are intended to be within the spirit and scope of this disclosure. While some examples presented herein involve specific combinations of functions or structural elements, it should be understood that those functions and elements may be combined in other ways to accomplish the same or different objectives. In particular, acts, elements, and features discussed in connection with one embodiment are not intended to be excluded from similar or other roles in other embodiments. Additionally, elements and components described herein may be further divided into additional components or joined together to form fewer components for performing the same functions. Accordingly, the foregoing description and attached drawings are by way of example only, and are not intended to be limiting.