Abstract:
The Automated Roof Runoff Management System mitigates the impact of storm water overwhelming existing infrastructure to handle it by automatically retaining storm water on roofs and releasing it at times where the system has adequate capacity to handle the retained water.

Description:
TECHNICAL FIELD AND INDUSTRIAL APPLICABILITY OF THE INVENTION 
       [0001]    This invention relates to the collection and release of water from a building roof, and more specifically relates to a novel valve and control system therefore to deliver such water from the roof in a controlled manner. 
       BACKGROUND OF THE INVENTION 
       [0002]    The growth of cities has increased reliance on undersized storm water conveyance systems. The high concentration of impervious area and undersized storm water systems in older cities, such as New York, Philadelphia, Washington D.C., causes several problems 1) pollution from sewage overflows and other contaminants 2) stream degradation and 3) flooding. In many cities the storm water system shares infrastructure with the sanitary sewer in what is called a combined sewer system. During storm events, runoff from impervious surfaces such as roofs and pavement causes the storm water system to overflow into the wastewater sewer system, and vice versa, which result in combined sewer overflows (CSO). That is, when the system is overloaded, the untreated combination of storm water and effluence overflows directly into the local waterways. 
         [0003]    For the purposes of this invention, the term “storm water system” includes includes storm drains, underground pipes, retention ponds, tanks, ditches, channels, natural bodies of water, and any other system that receives storm water runoff. 
         [0004]    Many urban municipalities have increased storm water management regulations to reduce problems related to stormwater runoff. A common regulation mandates that a developed real estate property must store the first one (1) inch of storm water for a minimum of seventy-two (72) hours after the rain gauge senses the end of the storm event. The regulation varies between municipalities but the popularity of stringent storm water regulations is on the rise. This increase in regulation translates into increased costs for developers and, in some municipalities, all property owners. 
         [0005]    The most common methods of on-site roof-top storm water mitigation are green roofs, gray water harvesting, and blue roofs. Green roofs treat storm water by storing it in the growing media and releasing it back into the hydrologic cycle through evapotranspiration. Grey water harvesting systems utilize storm water for property and building systems that do not require potable water (i.e. irrigation, toilet flushing, car wash). Blue roofs are systems of weirs installed throughout the roof that slow the discharge of the storm water by extending the time it takes to get to the down spout or roof drain. It is not uncommon for these systems to be utilized in combination, or in sequence as well. All of these systems represent an increased cost for proposed development and substantial costs to existing buildings. 
       BRIEF SUMMARY OF THE INVENTION 
       [0006]    In accordance with the invention, a novel controllable valve is installed in the path of water accumulated on a roof or other structure, thus retaining the water on the roof to be discharged at a later time. The controllable valve communicates with a central computer. Based on weather forecasts, current precipitation, and other sensor data, the valve closes to retain water at key times to keep the underground storm water system from reaching overcapacity. 
         [0007]    The valve is computer controlled, responding to commands from the computer, which determines the optimal performance of the system based on the outputs of a weather forecasts, rooftop sensors, as well as sensors within the storm water system. The computer uses the information from these devices to determine the optimal time to close the valve and retain water on the rooftop, as well as open the valve and release the collected water when the system can handle the additional volume. 
         [0008]    The valve may be affixed directly to a scupper, roof drain, or down spout and realeases water based on algorithms that determine the best time to release the water into the main underground storm drain. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  is a partial cross-sectional drawing of a valve from the first embodiment in a closed position and secured to a building roof and its down spout. 
           [0010]      FIG. 2  a view of a rooftop with an automated runoff management system from the second embodiment installed. 
           [0011]      FIG. 3  is a cross-sectional drawing of a valve from the second embodiment in a closed position and installed on a roof top. 
           [0012]      FIG. 4  is a block diagram of the control flow from the first embodiment. 
           [0013]      FIG. 5  is a block diagram of the control flow from the second embodiment. 
           [0014]      FIG. 6  is a block diagram of the control flow for determining the optimal time to close the valves in the second embodiment. 
           [0015]      FIG. 7  is a block diagram of the control flow for determining the optimal time to open the valves in the second embodiment. 
           [0016]      FIG. 8  is a partial cross-sectional diagram of the base station in the second embodiment. 
           [0017]      FIG. 9  is a diagram of a municipal rooftop runoff management system as in the third embodiment. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     First Embodiment, FIGS.  1 - 2 ,  4   
       [0018]    The first embodiment describes an automated roof drain valve that delays runoff by a set time delay after precipitation has ended, or can be networked together with a computer to retain and release water based on the calculated optimal times to retain water on the building. 
         [0019]    Referring to  FIG. 1  there is shown the novel valve assembly  110  of the invention which is suitably secured to a building parapet wall  111  and the building facade  112 . Valve assembly  110  extends through a sealed opening in roof  113 . The valve assembly has a slotted opening  114  to receive rain water and the like accumulated on the roof  113 , and a discharge opening  116  connected to the roof downspout  117  (or an in-deck drain). The slotted opening  115  has a restricted height to act as a debris guard. The valve  118  is shown as a cylindrical valve body raised and lowered by an actuator  119  between its raised (open) position and lowered (closed) position. Actuator  119  is electrically controlled by a controller  123 . The valve height is set so the water level on the roof  113  cannot exceed a maximum depth  120 , above which it will spill over the top of the closed valve  118 . Valve  118  is also equipped with a seep hole  121  to ensure that the roof  113  will drain even if actuator  119  were to become stuck. Any other type of valve structure can be employed in accordance with the invention. The valve is opened when it is desired to discharge fluid from roof  113  to downspout  117  (or other discharge channel). 
         [0020]    Valve assembly  110  may also contain a rain gauge  122  that is connected to controller  123 . Controller  123 , rain gauge  122  and actuator  119  are powered by a suitable supply such as a battery, potentially charged by a solar collector, or a mains powered transformer. Controller  123  may also communicate with other valves, an on-site computer, or a remotely located computer, which notifies it when to open and close. 
       First Embodiment Operation, FIG.  4   
       [0021]      FIG. 4  shows the control flow implemented in controller  123 . 
         [0022]    By default valve  118  is positioned in its raised, open, position. Upon detection of precipitation by rain gauge  122  or communication from remote computer, controller  123  signals actuator  119  to close valve  118 . 
         [0023]    When rain detector  122  senses the end of precipitation or is notified by the remote computer, controller  123  signals actuator  119  to open valve  118 . 
         [0024]    If precipitation is detected during the delay, controller  123  signals actuator  119  to close the valve  118 . 
         [0025]    If valve  118  is closed and the water level on roof  113  exceeds the height of valve  118  it will drain through the hollow center of valve  118 , thus ensuring that the water retention capacity of roof  113  is limited. 
         [0026]    Also, if valve  118  is closed and some failure causes actuator  119  to become stuck, retained water will drain slowly through seep hole  121  ensuring that the retained water will not become stagnant or polluted with algae or mosquito larvae. 
       Second Embodiment, FIGS.  2 - 3 ,  5 - 8   
       [0027]    The second embodiment describes an automated rooftop runoff management system that controls runoff from a rooftop optimally according to one or more criteria dictated by an authority such as federal or state law, federal, state or municipal regulations, or owner set criteria, using currently retained depth of water, current precipitation, forecasted precipitation, and capacity sensors in the receiving storm water system. 
         [0028]      FIG. 2  shows a building roof with an automated runoff management system installed. Roof parapet  200  and roof liner  201  retain precipitation and drainage from the roof is is controlled by automated drains  202 . Base station  203  detects precipitation with rain gauge  204  and is also connected to a suitable power supply and a network connection to a weather forecast data feed. 
         [0029]      FIG. 3  is a detail view of automated drain  202 . Housing  301  is attached and sealed to roof  302  and drain  303 . Cylindrical valve  304  is raised and lowered by actuator  305  between its lowered, closed, position and raised, open, position. Actuator  305  is electrically controlled by controller  306 , which is also electrically connected to depth sensor  307  and antenna  308 . Actuator  305 , controller  306 , and depth sensor  307  are all powered by a suitable supply (not shown) such as a mains powered transformer or a battery charged by solar cells. 
         [0030]    Controller  306  communicates wirelessly with base station  203  through antenna  308 , or some other suitable network. 
         [0031]    Valve  305  has a limited height to ensure that the amount of retained water on the roof cannot exceed maximum water depth  309 , in which case it will drain over the top of closed valve  305 . 
         [0032]    Valve  305  is also designed with seep hole  310  to ensure that if actuator  305  were to become stuck with valve  304  in the closed position, retained water will drain slowly and not become stagnant and potentially polluted with algae and mosquito larvae. 
         [0033]      FIG. 8  shows base station  203 . Housing  801  protects the contents against handling and weather. Computer  802  is powered with some suitable power through power chord  805 , and receives data from rain gauge  204  through rain gauge wire  804 . 
         [0034]    Computer  802  communicates wirelessly with automated drains  202  through antenna  803  or some other suitable network connection, and communicates with a precipitation forecast data source and other base station  203 s through network connection  806  or some other suitable network connection such as wireless broadband. 
       Second Embodiment Operation, FIGS.  2 - 3 ,  5 - 8   
       [0035]      FIG. 5  shows the control flow implemented on computer  802 . The normal position of valves  304  is open. Based on readings from depth sensor  307 , rain gauge  204  and precipitation forecasts received through network connection  806  the optimal time to close valves  304  is calculated according the control flow outlined in  FIG. 7  and the optimal time to close valves is calculated according to the flow outlined in  FIG. 6 . When valves  302  are open, the optimal closing time is continually calculated until the current time and the optimal closing time are identical, at which time valves  302  are closed. When valves  302  are closed, the optimal opening time is continually calculated until the current time and the optimal opening time are identical, at which time valves  302  are opened. 
         [0036]      FIG. 6  outlines the flow for calculating the optimal time to close valves  304 . The times for opening and closing valves are incrementally increased and for each setting the runoff profile is calculated and then evaluated against criteria set by law, regulatory agencies, municipalities or owners. The valve  304  closing time for the optimal runoff profile as evaluated against these criteria is selected as the optimal closing time. 
         [0037]      FIG. 7  outlines the flow for calculating the optimal time to open valves  304 . The times for opening and closing valves are incrementally increased and for each setting the runoff profile is calculated and then evaluated against criteria set by law, regulatory agencies, municipalities or owners. The valve  304  opening time for the optimal runoff profile as evaluated against these criteria is selected as the optimal opening time. 
         [0038]    Top open or close the valves the base station  203  sends a network signal to controllers  306  in all automated drains  202 . The controller  306  then sends an electrical signal to actuator  305  to open or close the valve. 
         [0039]    Readings from depth sensor  307  in each automated drain  203  are sent by network signal to base station  203  for storage and use in calculating runoff profiles. 
         [0040]    Base station  203  retrieves precipitation forecasts from weather services such as NOAA or Weather Underground over network connection  806  on a regular basis, such as every 15 minutes. 
         [0041]    Base station  203  retrieves current precipitation from rain gauge  204  through rain gauge wire  804 . 
       Third Embodiment, FIG.  2 - 3 ,  9   
       [0042]    The third embodiment describes a rooftop runoff management system consisting of a plurality of individual rooftop management systems as in the second embodiment, collectively controlling runoff from the plurality of rooftops optimally according to one or more criteria dictated by an authority such as federal or state law, federal, state or municipal regulations, or owner set criteria, using currently retained depth of water, current precipitation and forecasted precipitation. 
         [0043]      FIG. 9  is a diagram of a municipal rooftop runoff management system in which a plurality of rooftop runoff management systems  901  as in the second embodiment are connected to a central server  904  over a private or public network  902  through network connections  903 . 
       Third Embodiment Operation 
       [0044]    In this embodiment different rooftop runoff management systems  901  may open or close valves  304  at different times than other rooftop management systems  901 , in order to optimize runoff across the entire municipality. 
         [0045]    If a rooftop runoff management system  901  is unable to communicate with central server  904  it will operate as described in embodiment  2 . 
         [0046]    If a rooftop management system  901  is capable of communicating with central server  904  the selection of times when to open valves  304  in the rooftop runoff management system  901  is determined by the central server based on valve  304  status, depth sensor  307  status and rain gauge  204  status from the plurality of rooftop management systems  901 . For example, regulation may only allow a subset of the plurality of rooftop management system  901  s to discharge concurrently. 
         [0047]    Although the present invention has been described in relation to particular embodiments thereof, many other variations and modifications and other uses will become apparent to those skilled in the art. It is preferred, therefore, that the present invention be limited not by the specific disclosure herein.