Abstract:
A desiccant dehumification system uses an air heater incorporating air feedback from the exhaust and/or the return air fans. The air and gas are mixed in a single step, two step, or continuous modulation mixing valve. An outdoor cooking grill style burner allows a small unit to be made with tight air heating system. One system cools the return air making it cool and humid. A portion of this air is then dried by a desiccant dehumidification system which makes hot and dry output air. The remaining return air is then dried by desiccant dehumidification system output air to deliver processed air in a controlled comfort range. A second system mixes return air with fresh air making mixed return air which is dried in a desiccant dehumidification system and then cooled to a desired comfort range without condensation.

Description:
RELATED APPLICATION 
   This application is based upon International Application Number PCT/US03/03729 filed 6 Feb. 2003 entitled Desiccant Dehumidification System the priority of which is claimed, the subject matter of which is incorporated herein and made a part hereof by reference. 
   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   It has always been a desire to manipulate atmospheric conditions for comfort and to meet specific conditions required for certain facilities. Typically, these prior art systems have directly heated or cooled the outside air or air return from a structure and then exhausted the air into the structure. One of the effects of heating or cooling an air stream is the resulting change in the moisture content of the air. It is well recognized that the comfort of a structure is not only dependent on the temperature of the atmosphere but also on the humidity level. It is also desired to maintain specific temperature and/or humidity levels in structures. 
   There is a need for an economical and efficient system that can treat air to achieve a determined zone of humidity and temperature within a structure and/or within a zone of a structure. The present invention provides a system for conditioning air that meets these demands in an economical and efficient manner. 
   2. Description of the Prior Art 
   The use of systems for conditioning air of known design and configurations is known in the prior art. More specifically, systems for conditioning air of known design and configurations previously devised and utilized for the purpose of conditioning air are known to consist basically of familiar, expected, and obvious structural configurations, notwithstanding the myriad of designs encompassed by the crowded prior art which has been developed for the fulfillment of countless objectives and requirements. 
   By way of example, U.S. Pat. No. 5,826,434 to Belding discloses a high efficiency outdoor air conditioning system. U.S. Pat. No. 6,199,388 to Fischer discloses a system and method for controlling temperature and humidity. U.S. Pat. No. 6,003,327 to Belding discloses a method and apparatus for cooling warm moisture-laden air. U.S. Pat. No. 5,667,560 to Dunne discloses a process and apparatus for dehumidification and VOC odor remediation. U.S. Pat. No. 5,649,428 to Calton et al. discloses a hybrid air-conditioning system with improved recovery evaporator and subcool condenser. Lastly, U.S. Pat. No. 5,632,954 to Coellner et al. discloses a method for killing microorganisms. 
   While these devices fulfill their respective, particular objectives and requirements, the aforementioned patents do not describe a desiccant dehumidification system that allows removing humidity from the air while maintaining a desired comfort factor corresponding to a desired combination of temperature and humidity. 
   In this respect, the desiccant dehumidification system according to the present invention substantially departs from the conventional concepts and designs of the prior art, and in doing so provides an apparatus primarily developed for the purpose of removing humidity from the air while maintaining a desired comfort factor corresponding to a desired combination of temperature and humidity. 
   Therefore, it can be appreciated that there exists a continuing need for a new and improved desiccant dehumidification system which can be used for removing humidity from the air while maintaining a desired comfort factor corresponding to a desired combination of temperature and humidity In this regard, the present invention substantially fulfills this need. 
   SUMMARY OF THE INVENTION 
   A desiccant dehumidification system of the type for reducing the moisture content of a stream of air to be exhausted to an area is provided. The desiccant dehumidification system includes a housing partitioned into a first and a second air chamber for passing air there through. A desiccant wheel is rotatably positioned across both air chambers in a manner such that moisture is removed from the air stream in the first chamber and moisture is removed from the desiccant wheel by an air stream in the second chamber. The second chamber further includes an air heater positioned to heat the air stream before passing across the desiccant wheel to remove moisture therefrom. The air heater is charged with a slip stream, or portion of the air stream, passing through the first air chamber and/or the second air chamber. 
   The air heater may be a fuel burner wherein the heater may be further controlled by the introduction of air from the first air chamber and/or the second air chamber. Utilization of a portion of air energized within one or both of the air chambers increases the efficiency of the present invention reducing energy costs and increasing energy conservation. 
   The present invention may further include a mixing of return air from a structure and fresh air. The system of the present invention may further include cooling and/or heating mechanisms upstream of the dehumification station or after the dehumidification station. 
   The system of the present invention may be utilized as a stand alone system for conditioning of air or in conjunction with current air conditioning systems to further control the desired conditions of an atmosphere. 
   There has thus been outlined, rather broadly, the more important features of the invention in order that the detailed description thereof that follows may be better understood and in order that the present contribution to the art may be better appreciated. There are, of course, additional features of the invention that will be described hereinafter and which will form the subject matter of the claims attached. 
   In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of descriptions and should not be regarded as limiting. 
   As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention. 
   It is therefore an object of the present invention to provide a new and improved desiccant dehumidification system which has all of the advantages of the prior art systems for conditioning air of known design and configurations and none of the disadvantages. 
   It is another object of the present invention to provide a new and improved desiccant dehumidification system which may be easily and efficiently manufactured and marketed. 
   It is a further object of the present invention to provide a new and improved desiccant dehumidification system which is of durable and reliable constructions. 
   An even further object of the present invention is to provide a new and improved desiccant dehumidification system which is susceptible of a low cost of manufacture with regard to both materials and labor, and which accordingly is then susceptible of low prices of sale to the consuming public, thereby making such desiccant dehumidification system economically available to the buying public. 
   Even still another object of the present invention is to provide a desiccant dehumidification system for removing humidity from the air while maintaining a desired comfort factor corresponding to a desired combination of temperature and humidity. 
   Lastly, it is an object of the present invention to provide a new and improved desiccant dehumification system using an air heater that incorporates air feedback from the exhaust and/or the return air fans. The air and gas are mixed in a mixing valve. The mixing valve may be a single step, a two step or a continuous modulation valve. An outdoor cooking grille style burner allows a small unit to be made with tight air heating controls. The desiccant dehumidification system is combined into two desiccant air conditioning systems. One system cools the return air making it cool and humid. A portion of this air is then dried by a desiccant dehumidification system which makes output air that is hot and dry. The remaining return air is mixed with the desiccant dehumidification system output air to deliver processed air in a controlled comfort range. A second system mixed return air with fresh air to make mixed return air which is dried in a desiccant dehumidification system. The dried return air is then cooled to a desired comfort range without condensation. 
   These together with other objects of the invention, along with the various features of novelty which characterize the invention, are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and the specific objects attained by its uses, reference should be had to the accompanying drawings and descriptive matter in which there are illustrated preferred embodiments of the invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be better understood and objects other than those set forth above will become apparent when consideration is given to the following detailed description thereof. Such description makes reference to the annexed drawings wherein: 
       FIG. 1  is a block diagram of a desiccant dehumidification system (DDS) according to an embodiment of the present invention. 
       FIG. 2  is a block diagram of a desiccant air conditioning system (DACS) according to an embodiment of the present invention where return air is mixed with conditioned air to create air for a living space; and 
       FIG. 3  is a block diagram of a DACS according to an embodiment of the present invention where fresh air is mixed with return air to generate air that is further conditioned to create air for a living space. 
   

   The same reference numerals refer to the same parts throughout the various Figures. 
   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   In the following description, numerous specific details are set forth to provide a thorough understanding of the present invention. However, it will be obvious to those skilled in the art that the present invention may be practiced without such specific details. In other instances, well-known mechanical subsystems have been shown in block diagram form in order not to obscure the present invention in unnecessary detail. For the most part, details concerning particular fan types, motors, valves and the like may have been omitted inasmuch as such details are not necessary to obtain a complete understanding of the present invention and are within the skills of persons of ordinary skill in the relevant art. 
   Refer now to the drawings wherein depicted elements are not necessarily shown to scale and wherein like or similar elements may be designated by the same reference numeral throughout the several drawings. 
     FIG. 1  is a block diagram of a desiccant dehumidification system (DDS)  100  according to one embodiment of the present invention. DDS  100  includes a housing  96  partitioned into two separate chambers, a first air chamber  98  and a second air chamber  99 , by partition  116 . This ensures that the air in each partition are relatively separate during processing. Desiccant wheel  101  is rotated so that its surfaces  117  and  118  are exposed to the air in one or the other of the partitions determined by partition  116 . Desiccant wheel  101  is a porous structure and is has contained therein a desiccant material that absorbs water from air passing over it. 
   Processed air  105  is delivered to some space, e.g., a living space, with an air condition depending on its use. Return air  114  is air that has been exposed to the environment of the living space and is being returned to DDS  100  to be re-conditioned. Fan  102  pulls in return air  114  and forces it as pressurized return air  104  through desiccant wheel  101  from surface  117  to surface  118  where it exits as processed air  105 . During this process, desiccant wheel  101  takes moisture out of pressurized return air  104 . As moisture is taken from pressurized return air  104 , its temperature rises and its relative humidity drops (energy is removed from the air). Processed air  105  has less humidity and a higher temperature than pressurized return air  104 . 
   Source air  106  is air that is separate from return air  114 , and processed air  105 , for example it may be outside environment air. Fan  103  creates a pressure drop across the lower half of desiccant wheel  101  in the partition of DDS  100  below partition  116 . Air beater  119  comprises a burner  105  with a gas (combustible) inlet line  111  and a gas/air mixing unit  110 . The gas in gas line  111  is pressurized and is mixed with air from air line  112 . The mixing may be done two ways. Mixing unit  110  may be simply a chamber that uses the action of venturi  109  to “pull” air from air line  112 . Alternatively, mixing unit  110  may comprise a controllable mixing valve, not shown. If mixing line  111  comprises a mixing valve it may be a single step, a two step or a continuous modulation valve. Burner  108  has an igniter, not shown, for lighting the gas/air mixture from mixing unit  110  as it exits the orifices of the burner creating flame  120 . Burner  108  may be designed to operate like a burner for an outdoor cooking grill. 
   Source air  106  is heated and becomes heated source air  107  as it passes through burner  108 . Heated source air  107  passes through the portion of desiccant wheel  101  that has absorbed water from the return air  104 . The heated source air  107  picks up moisture from desiccant wheel  101  creating exhaust air  128  (cooler and wetter than heated source air  107 ) which fan  103  delivers as exhaust air  115 . The portion of desiccant wheel  101  that has had moisture removed by heated source air  107  returns to the return air stream hotter and dryer to again pick up moisture from return air  104 . 
   Fan  102  may have a portion of its return air  104  channeled with air line  113  back to air line  112  which may alternatively receive air from exhaust air  115  via fan  103 . Further burner  108  to operate, the gas in gas line  111  must be mixed with air to enable combustion to take place. The system  100  super charges the air stream for combustion by combining a portion of the pressurized return air  104  and/or pressurized exhaust air  115 . If more volume of processed air  105  is required, then naturally burner  108  would have to be turned up along with increasing the speeds of fans  102  and  103 . The air volume for burner  108  from line  112  would likewise increase resulting in regulation of burner  108 . 
     FIG. 2  is a diagram of a desiccant air conditioning system (DACS)  200  that operates according to another embodiment of the present invention. DACS  200  has three major sections; return air cooler  201 , desiccant dehumidifying system (DDS)  202 , and air delivery duct  207 . 
   Return air cooler  201  has a chamber  203  and a chamber  205  separated by a cooling heat exchanger  204 . Fan  206  is coupled to air delivery duct  207  and pulls air from the return air  220  and pressurizes it and delivers it to air delivery duct  207  as pressurized return air  221 . DDS  202  is coupled to air delivery duct  207  with duct  28  and duct  213 . A portion of pressurized return air  221  is channeled through duct  208  as the input air  22  to DDS  202 . DDS  202  operates the same as DDS  202  described relive to  FIG. 1 . Desiccant wheel  210  rotates between the partitions of DDS  202  determined by partition  227 . The upper partition is further divided by desiccant wheel  210  into chambers  209  and  211 . Fan  212  pulls input air  222  into chamber  209  across desiccant wheel  210  that removes moisture and raises the temperature of output air  223 . Output air  223  is delivered back to air delivery duct  207  where it is mixed with air  224  to form processed air  214  for the living space  230 . 
   Source air  225  is heated by air heater  216  in chamber  215 . Heated air  228  passes through desiccant wheel  210  where it picks up moisture that desiccant wheel  210  extracted from input air  222 . This humid air exits from chamber  218  as exhaust air  226 . 
   Return air conditioner  201  takes return air  220  which is warm with a certain relative humidity and delivers pressurized return air  221  which is cooler with a higher relative humidity. DDS  202  then dries a portion of pressurized return air  221  (input air  222 ) and delivers it as output air  223  which is warm dry air. The remaining air  224  (cool and with high relative humidity) is mixed with output air  223  (hot and warm) to deliver processed air  214  which is warmer and dry and is within a desired comfort zone. A controller (not shown) receives the temperature and relative humidity of processed air  214 , return air  220 , and output air  223  to adjust parameters of DACS  200  (e.g., fan  212  speed, heater  216  temperature, fan  229  speed, fan  206  speed, etc.) to control the temperature and humidity for the processed air  214 . Processed air  214  is delivered at a comfort level using less energy than is possible with a standard air condition system. 
     FIG. 3  is another hybrid desiccant air conditioning system (HDACS)  300  according to embodiments of the present invention. HDACS  300  has two primary sections, air mixing chamber  302  and desiccant air conditioning system (DACS)  301 . Mixing chamber  302  receives return air  315  and fresh air  314  and mixes them to form mixed air  316  which is delivered to chamber  303  in DACS  301 . Partition  313  separates DACS  301  into a desiccant dryer section with chambers  310 ,  311 ,  303  and  305  and cooling section with shared chamber  305  and chamber  307 . Desiccant wheel  304  operates across partition  313  that separates the return air stream from the source/exhaust air stream. Fan  308  is the air mover for the section above partition  313 . 
   Air mixing chamber  302  allows a measured portion of outside fresh air  314  to be mixed with the return air  315  to control the air exchange rate for the living space  330 . Fan  308  pulls mixed air  316  through desiccant wheel  304  which extracts moisture delivering input air  317  which is hotter and dryer than mixed air  316 . Exhaust fan  312  pulls source air  319  into chamber  310  where it is heated with air heater system  309  delivering output air  320  which is hot and of low relative humidity. Output air  320  is pulled through desiccant wheel  304  where it extracts moisture from the desiccant and exits into chamber  311 . The air in chamber  311  is removed by fan  312  as exhaust air  320 . Exhaust air  321  is cooler and more humid than output air  320 . 
   Mixed air  316  undergoes a desiccant drying cycle which removes energy from the air and delivers output air  317  which is hotter and dryer. Output air  317  is then pulled through cooling heat exchanger  306  which simply cools out air  317  and delivers it to chamber  307 . The air from chamber  307  is then delivered to living space  330  as processed air  318 . The cooling of output air  317  decreases the temperature of the air and increases its relive humidity. The air processing cycle achieved with HDACS  300  uses less energy than conventional air conditioning systems and results in a system having no or low condensation. Air heater system  309  may operate the same as air heater system  119  as described relative to  FIG. 1 . If air system  309  uses a burner like burner  108 , then air feedback could be coupled from fan  308  and  312  with corresponding air lines (e.g. like  113  and  112  respectively) 
   U.S. Pat. No. 5,373,704 to McFadden may also provide exemplary procedural and/or other details supplementary to the above disclosure, and is specifically incorporated herein by reference. 
   As to the manner of usage and operation of the present invention, the same should be apparent from the above description. Accordingly, no further discussion relating to the manner of usage and operation will be provided. 
   With respect to the above description then, it is to be realized that the optimum dimensional relationships for the parts of the invention, to include variations in size, materials, shape, form, function and manner of operation, assembly and use, are deemed readily apparent and obvious to one skilled in the art, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present invention. 
   Therefore, the foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.