Abstract:
A CO 2  generation and control system for controlling ambient gas CO 2  concentrations in a controlled environment agriculture facility, including a housing, a controller disposed within said housing, a CO 2  gas supply electronically coupled to said controller so as to receive control signals from said controller; wherein said controller includes a plurality of data ports for connection to one or more environmental condition sensors, and further includes software, which when executed receives and responds to signals from said one or more data ports and adjusts gas output from said gas supply in response thereto, the adjustments being infinitely adjustable between no gas output to high gas output.

Description:
CROSS REFERENCES TO RELATED APPLICATIONS 
       [0001]    The present application claims the benefit of U.S. Provisional Patent Application Ser. No. 62/063,762, filed Oct. 14, 2014. 
     
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0002]    Not applicable. 
       THE NAMES OR PARTIES TO A JOINT RESEARCH AGREEMENT 
       [0003]    Not applicable. 
       INCORPORATION BY REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC 
       [0004]    Not applicable. 
       BACKGROUND OF THE INVENTION 
       [0005]    1. Field of the Invention 
         [0006]    The present invention relates most generally to environmental control systems for use in controlled environment agriculture (“CEA”) facilities, and more particularly to atmospheric gas control systems for CEA facilities, and still more particularly to a CO 2  generator and controller for monitoring, generating, and thereby enriching CO 2  gas concentrations in the atmosphere surrounding agricultural crops, and/or horticultural and pharmaceutical plants in a CEA facility. 
         [0007]    2. Background Discussion 
         [0008]    It is well-established that plant and crop yields can be increased by enhancing CO 2  concentrations in the atmosphere immediately surrounding the growing plants. When the many variables affecting plant metabolism and growth are closely controlled—such as light, nutrients, temperature, humidity, soil and water pH, and the like—there are measurable benefits to be realized by providing and controlling increased atmospheric CO 2  concentrations. The accepted optimal concentration is now understood to be approximately 1500 ppm for plants generally, while normal atmospheric concentrations at sea level average around 300 ppm. Greater concentrations than 1,500 ppm can be toxic to the plants, and lower concentrations results in slower growth rates. Accordingly, it is desirable to keep atmospheric CO 2  at optimal elevated levels in CEA facilities. 
         [0009]    However, not all controlled environment agriculture (“CEA”) facilities are the same. Grow room size, air circulation patterns, light heating and cooling systems, the integrity of seals on greenhouse panels, doors, and windows, and so forth, can all have considerable effects on CO 2  gas containment and escape. Accordingly, a system to maintain CO 2  at optimal levels must both monitor ambient concentrations and must generate gas in precise amounts. 
         [0010]    Unfortunately, known systems operate in binary fashion only—on or off—and do not provide CO 2  generation in amounts carefully tailored to changing grow room conditions. At a minimum, such systems waste energy, and therefore money, but they also fail to create the optimal growing conditions for plants, which is also wasteful and uneconomical, inasmuch as growing times are extended, delaying product readiness for markets, and resources needed for plant growth are consumed over longer periods of time. Indeed, this is the perennial problem for CEA operators: how to produce high quality marketable crops and plants using resources in the most economical way. It is well understood that achieving those ends requires careful resource control strategies and techniques that manage plant growth resources (water, air, light and dark, nutrients, temperature, humidity, etc., and CO 2 ), while balancing the provision of optimal resources with practical costs. The present invention addresses this need. 
       SUMMARY OF THE INVENTION 
       [0011]    The present invention is a CO 2  generation and control system for controlling ambient gas CO 2  concentrations in a controlled environment agriculture facility. The system includes a housing, a controller disposed within the housing, a CO 2  gas supply electronically coupled to the controller so as to receive control signals from the controller. The controller includes a plurality of data ports for connection to one or more environmental condition sensors, and further includes software, which when executed receives and responds to signals from the data ports and adjusts and finely tunes the gas output from the gas supply in response to the received sensor input. Unlike prior art systems, the adjustments are infinitely adjustable between no gas output to high gas output. 
     
    
     
       BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS 
         [0012]    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: 
           [0013]      FIG. 1  is an upper front right perspective view of the CO2 generator of the present invention; 
           [0014]      FIG. 2  is a lower front right perspective view thereof; 
           [0015]      FIG. 3  is lower right perspective view of the gas valve and burner assembly of the CO2 generator, shown removed from the generator housing; 
           [0016]      FIG. 4  is a lower left perspective view thereof; 
           [0017]      FIG. 5  is an upper left perspective view thereof; 
           [0018]      FIG. 6  is an upper right perspective view thereof; 
           [0019]      FIG. 7  is a bottom plan view thereof; 
           [0020]      FIG. 8  is a top plan view thereof; 
           [0021]      FIG. 9  is a front view in elevation showing the controller employed in the inventive system; 
           [0022]      FIG. 9A  is schematic front view in elevation of the input buttons presented on the face of the controller; 
           [0023]      FIG. 10  is a bottom plan view of the controller; and 
           [0024]      FIG. 11  is a schematic block diagrammatical flowchart showing the method comprising programs made up of computer executable instructions for execution by the controller according to a preferred embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0025]    The present invention is a CO 2  generation and control system that provides finely tailored control of ambient CO 2  concentrations in a controlled environment agriculture facility to ensure optimal atmospheric concentrations for plant growth. 
         [0026]    Referring first to  FIGS. 1 through 11 , wherein like reference numerals refer to like components in the various views, there is illustrated therein a new and improved CO 2  generator as used in a preferred embodiment of the inventive system, the generator denominated  10  herein. 
         [0027]    Referring next particularly to  FIGS. 1-2 , there is shown the CO 2  generator housing and burner assembly. The orientation in the views show the housing laid over on its side. These views further show that the generator housing and burner assembly  10  includes a housing  12  having a top side  14 , a right side  16 , a left side  18 , a front side  20 , a back side  22 , and an open bottom  24 . The top side  14  is a panel that may include hanging hardware  26 , such as eyebolts, for hanging the generator from a greenhouse/grow room ceiling. A plurality of air vents  28  for providing air to the burners and circulating air through the interior volume of the lower portion  12   a  of the housing are disposed in rows around various sides of the lower portion  12 A of the generator housing; conversely, CO 2  outlet vents  30  and openings  32  are disposed around the upper portion  12   b  of the housing  12  on the front, right and left sides. The housing (or case) is preferably fabricated from sheet metal and is intended for placement above the plant canopy in a CEA growing environment (such as a greenhouse or nursery) so as to ensure that CO 2  gas descends down onto plants as it is generated. 
         [0028]    Disposed within the housing is a gas valve and burner assembly  40 , which effectively bifurcates the housing, dividing the interior into a lower systems portion  12   c  and an upper plenum and gas outlet portion  12   d.    
         [0029]    Referring next to  FIGS. 3-8  there is shown the burner and gas valve assembly  40  incorporated into the CO2 generator of the present invention. This assembly includes a panel support  42  with side flanges for connection to the inside of the steel case. Disposed generally central within the panel area is a burner frame  44  in which a plurality of LO-NOx natural gas or liquid propane burners  46  are horizontally mounted and disposed in a generally parallel array. In a preferred embodiment, six burners are employed, two burners  46   a  supplied with gas from a first gas supply pipe  48  and four burners  46   b  supplied from a second gas supply pipe  50 , sharing an electronic ignition  52  element so as to eliminate the need for an open pilot flame. Further, the burners share a single electron-based sensor, wherein the flame sensor measures electrons present in the blue flame. When the first bank of two burners ignites, the system registers that it has ignited and then checks programming to determine whether 2, 4, or 6 burners should be operating at low, medium, or high outputs). If 2 burners should be operating, nothing further happens (i.e., no further burners are ignited. If 4 burners should be operating, the solenoid valve for the second burner bank  46   b  opens, and after a 10 second delay, the solenoid valve for burners  46   a  closes. If 6 burners should be operating, the solenoid valve for burners  46   b  opens, and the solenoid valve for burners  46   a  remains open. In operation burners  46   a  alone provide a low range of CO 2  outputs; burners  46   b  operated alone provide a medium range of CO 2  outputs; and burners  46   a  and  46   b  operated together provide a high range of CO 2  outputs. Fewer burners may be employed in smaller systems. The present preferred embodiment with six burners has outputs ranging from approximately 6 cubic feet per hour to approximately 32 cubic feet per hour, and as those with skill will appreciate, larger or more burners, larger supply volume, and so forth, will result in even greater range for larger facilities. The inventive concept, on the other hand, remains the same. 
         [0030]    Gas supplied through the first and second gas supply pipes is metered out through first and second electronic variable-output solenoid gas valves  54 ,  56 , each coupled to a general gas supply (not shown) through a gas coupling  58 , the valves having an analog (infinite) range of settings through their operational range from fully closed to fully open. Thus, the exact output of the system can be very finely tailored to produce CO 2  at a rate and in a range such that it keeps ambient CO 2  within a small window of errors near the system setpoint. A water condensation drain  60  is provided to drain water away from the burner array as expanding LP or natural gas gas creates condensation at and along the supply pipes. 
         [0031]    Disposed on the underside of the panel support  42  is an S-plate  62 , which provides a heat shield between the burner array and the PCB controller  64 . The PCB controller includes a power switch  66 , and on/off indicator light  68 , power connector  70 , and data input ports  72 , comprising, for instance, category 5 and RS 232 cable connectors, each connected to the CO 2  generator controller of the present invention (described more fully below). 
         [0032]    Through the data input ports, the PCB controller may be in a wired or wireless connection with the CO 2  generator controller  90  of the present invention (shown in  FIGS. 9-10 ), a wired connection made to connectors  92  and/or  94  on the controller. One of a plurality of power supply connectors  96   a - d  can be coupled to the generator power supply receptacle  70 , each of the controller power supply receptacles having a watertight cover. Alternatively, the generator power supply cord can be plugged directly into a main electrical system for the facility, and generator control is accomplished through wireless (e.g., TIA/EIA-485, formerly RS-485) communications between the generator at  72  and the controller at  92 . A first power connector  96   a  may be used to power a cooling device; a second power connector  96   b  may be connected to a heating device; a third connector  96   c  may be connected to the CO 2  generator; and a fourth power supply connector  96   d  may be connected to a humidifier/dehumidifier. The controller may receive data input from a probe or sensor (not shown) that detects any of a number of conditions, alone or in combination, such as light, temperature, gas concentration, humidity, etc., through data port  98 . Data port  100  is provided for connection to a computer, a wireless router, or other network connected device. When a photosensor is not included, the system may include a timer or system clock so that system operations can be determined or scheduled according to the time of day. Preferably, the generator controller is a high-impact injection molded enclosure suited for the rugged grow room environment, though metal enclosures are suitable alternatives. 
         [0033]    A resettable circuit breaker and/or on/off switch  102  is provided on the bottom of the controller. When functioning as a circuit breaker it facilitates rapid resetting of the system in the event of a voltage or current spike or surge. A main AC power input  104  connects to any 100-250V supply operative at 50-60 Hz. It may also permit the controller to be connected to and coordinated with other controllers in the CEA system, so as to gang or chain controllers, such that when the controller is disabled (for instance, to protect it from operating heavy load devices, such as exhaust fans, in the CEA environment). 
         [0034]    The user interface and control panel  110  on the controller  90  includes a keypad  112 , and LCD display  114 , a cooling device indicator light  116 , a heating device indicator light  118 , a CO 2  device indicator light  120  (indicating operable connection to the CO 2  generator), a humidity device indicator light  122 , a daytime indicator light  124 , TIA/EIA-485 RXD and TXD indicator lights  126 ,  128 , respectively, operable when the controller is connected to other devices in the local network; a CO 2  calibration light  130 , and a fuzzy logic indicator light  132 . 
         [0035]    Keypad keys include a set clock key  134  (for setting the date and time); a set humidity key  136  (for setting the humidity setpoint); a set day/night temperature key  138  (for setting the desired room temperatures during the day and at night); a set CO 2  ppm key  140  (for setting the CO 2  setpoint); an interlock humidity/temperature key  142  (for linking humidity to temperature and having corrections to the former be a function of measured values of the latter and/or for preventing an exhaust fan from operating at the same time as the CO 2  generator); a temperature hysteresis key  144  (for a response lag time for turning on heat/cooling devices so as not to have the devices switching on and off too often); an interlock CO 2 /temperature key  146  (allows a user to select whether CO 2  enrichment or reduction will operate independently of the cooling outlet, or if operation of the cooling outlet will defeat the CO 2  enrichment/reduction process); humidity hysteresis key  148  (to set a delay to prevent the humidifier from being switched on and off too frequently); an intelligence key  150  (to set the different setpoints for the various modes); a CO 2  hysteresis key  152  (so as to set how low below setpoint levels CO 2  must fall before beginning CO 2  enrichment again); a humidity mode key  154  (for switching between raising and lowering relative humidity); a minimum/maximum recall key  156  (for recalling the minimum and maximum recorded values for CO 2 , humidity, and temperature); a CO 2  calibrate key  158  (for calibrating and re-calibrating the CO 2  sensor connected to the controller); an Up key  160 ; a Down key  162 ; and an Enter/Reset key  164 , for accepting keypad entries). Note should be made that CO 2  hysteresis operates only when using a CO 2  generator in an on/off mode or the intelligence mode. When using a fuzzy logic mode, a compressed CO 2  gas source is rapidly turned on and off to keep gas levels with a narrow optimal range. Generally, however, it is not suggested to turn hydrocarbon-combustion systems off and on rapidly. Eventually a system may could be devised that use a variable solenoid that would allow for virtually infinite flame settings. 
         [0036]    As a possible default setting, intelligence mode will operate the CO 2  burners at high (for instance, all burners operating simultaneous with fully open valves) when CO 2  concentrations are below 750 ppm. It will operate the burners at medium production when the concentration is between 751-1250 ppm. And it will operate the burners in low mode when the concentration is 1251-1500 ppm. When the concentration is above 1500 ppm, the generator is put into standby mode. 
         [0037]    The inventive controller may be operated either with a CO 2  generator of the kind described above or with compressed CO 2 . The controller turns off connected devices through the power supply connectors  96   a - d . When operating in binary (on/off) mode, the controller turns CO 2  devices on/off through the power supply connector  96   c.  In the alternative, when in “intelligence mode,” analog and variable control inputs are conveyed through an 8 position 8 contact (8p8c) connector located on the bottom of the controller unit using port  92 . 
         [0038]    The controller is a proportional integral derivative (“PID”) using measured CO 2  levels, temperature, and humidity as the control loop process variables for PID control, and it is a fuzzy logic controller operating in binary (on/off) fashion when using open loop process variables. It can operate in any of P, PI, PID, and PD modes wherein control actions (powering on and/or off the connected devices) is accomplished by subtracting the various measurements of actual process variables values from the setpoints, calculating the control actions and multiplying each by the calculated error, and summing all three calculation results to derive a controller output. The controller eliminates the need for manual sampling and the guesswork typical of manually corrected environmental conditions. It provides accuracy within a few parts per million for CO 2  concentrations. 
         [0039]    Referring next to  FIG. 11 , there is shown a flow chart  200  of the control steps implemented upon execution of the control algorithm of the controller of the present invention. This is the software executed by the controller after power on  202  and system warm up  204 . At block  206  the system checks the main controller and any sensor connected to the TIA/EIA-485 connector. If it does not detect a connected sensor or detects a sensor fault, it displays a fault code  208  and passes to a prompt for the user to clear the fault or automatically clears the fault  210 , depending on the sensor and the detected error. It then loops back to box  206  until no fault is detected and then passes control to box  212 , where the sensor communications are tested. If faults are detected, the appropriate fault codes are displayed  214  to prompt manual correction or to clear the fault automatically  216 . Once the faults are cleared, the system enters into running mode  218 . 
         [0040]    Once the system is in running mode, control may pass to one of three operational modes: CO 2  mode, humidity mode, and temperature mode, depending on user inputs or on system defaults or programming. When temperature mode is entered  220 , block  222  performs a test to determine whether the temperature setpoint has been reached; if it has, the temperature relay is turned off  224 ; if it has not, the humidity sensor communication is broken  226 , and once that is accomplished the heater/cooler is operated until the setpoint is reached  228 , at which point the temperature control relay is turned off  230  and control passes back to box  220 , to loop back through temperature mode for as long as needed or desired. 
         [0041]    If humidity mode is entered  240 , the system conducts a test  242  to determine whether the humidity/temperature interlock has been elected by the operator. If it has not been chosen, the system enters into “split” mode  244 , and an initial test and calculation is performed at box  246  to ascertain whether the humidity setpoint has been reached; if it has, the humidity relay is turned off  248  and the system loops back to pass control to the entry point  240  for humidity mode; if it has not been reached, humidity sensor communication to the controller is broken off  250  to allow humidity to rise to the setpoint  252 , and control loops back through box  246  until the setpoint is reached. 
         [0042]    If at box  242  the humidity/temperature interlock has been selected, the system checks  254  to determine whether a humidity decrease is required, in which event the humidifier relay is turned on  256 , and if a decrease is not called for, the system checks to see whether the setpoint has been reached by passing through box  246  again. If the humidifier relay is turned on, the cooler relay is also forced on  258 . 
         [0043]    When the system enters CO 2  mode  260 , the system looks to see whether calibration mode has been manually entered  262 , in which event it waits for calibration to be completed  264 . If calibration mode has not been selected, the system checks photosensor or time clock readings to determine whether it is daytime or a preprogrammed on/off time  266 ; if it is not, it awaits daytime  268 ; if it is, it enters into CO 2  mode  270 . 
         [0044]    The system then checks at box  272  to determine whether the CO 2 /temperature interlock option has been manually selected by the user; if it has not, a succeeding check is made at box  274  to see whether intelligence mode is in operation and communicating through port  96   c  or regular mode communicating through port  92 ; if the interlock option has been selected, it then checks  276  to see whether cooling mode is on, and if it is, the CO 2  relay is turned off; if cooling mode is not on, control passes to box  274 . If Sentinel mode is selected, the system enters into automatic mode  278 , and control passes to test  280  to determine whether the setpoint has been reached, and if it has, the CO2 relay is turned off  282 ; and if it has not, the CO 2  sensor communication is broken off  284  and the system waits  286  until CO 2  levels reach setpoint concentrations  286 . If, at box  274 , Sentinel mode has not been selected, the system enters into normal control mode  288 , and control passes to box  280 , where processing continues as described. 
         [0045]    In an embodiment, the inventive system also includes a fail-safe feature that prevents the gas generator from persisting in gas generation mode. This is accomplished by detecting the connection between the controller and generator. If the TIA/EIA-485 connection is lost for a predetermined amount of time, the generator will go into a pause mode until communications are re-established. Thus, there is a constant duplex communication via TIA/EIA-485 between the controller and the generator rather than only a periodic sending of data and/or command signals. 
         [0046]    The above disclosure is sufficient to enable one of ordinary skill in the art to practice the invention, and provides the best mode of practicing the invention presently contemplated by the inventor. While there is provided herein a full and complete disclosure of the preferred embodiments of this invention, it is not desired to limit the invention to the exact construction, dimensional relationships, and operation shown and described. Various modifications, alternative constructions, changes and equivalents will readily occur to those skilled in the art and may be employed, as suitable, without departing from the true spirit and scope of the invention. Such changes might involve alternative materials, components, structural arrangements, sizes, shapes, forms, functions, operational features or the like. 
         [0047]    Furthermore, it will be appreciated that while the present system is particularly adapted for use in CEA, the controller can be incorporated in nearly any system using one or more environmental control devices. Explanation of the system using CEA as an exemplary field in which to implement the system is for purposes of illustration only, because control of a number of environmental variables—temperature, humidity, CO 2  gas concentrations, light, and so forth—is common in CEA. Those with skill in the art, however, will appreciate that concentrations of any atmospheric gas may be controlled using the inventive control and generation system. Further, gas enrichment is emphasized, as it is commonly practiced in CEA; but gas concentration reduction can also be accomplished using the controller of the present invention in connection with a gas scrubber system. Accordingly, reference to a particular kind of gas enrichment/reduction herein is not limiting. 
         [0048]    Therefore, the above description and illustrations should not be construed as limiting the scope of the invention, which is defined by the appended claims.