Abstract:
A programmable, user-controllable heat storage system and method to provide instant hot water on demand at the desired time while avoiding the waste of energy resulting from continuous pre-heating.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application claims the benefit of PCT Application No. PCT/US/14/11734, filed Jan. 15, 2014, which claims the benefit of U.S. Provisional Patent Application No. 61/752,918, filed Jan. 15, 2013, which is incorporated herein by reference in its entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates generally to heat storage devices for water, and specifically to a user-controllable programmable system and method for providing instant hot water when needed. 
       BACKGROUND 
       [0003]    Everyone is familiar with the problem of turning on the hot water tap and having cold water come out for the first few minutes. In most water systems, the hot water pipes that lead from the heater to the point of use (shower or tap) are filled with water when the tap or shower is not running. That water cools off during the time when the tap or shower is not in use; therefore, when the tap or shower is first turned on after a period of disuse, that cool water is the first water that comes out. Since most people are not interested in taking a cold shower when they need a hot shower, or in using cold water when they need hot water, that water is typically wasted. 
         [0004]    Various prior art systems address this issue. For example, a system typically used in hotels and similar accommodations comprises a hot water circulation facility, which continuously circulates hot water from a hot water source to the tap and then back to the hot water source. This prevents the water from cooling off and allows hot water to come out immediately when the hot water tap is turned on. However, such a system is not energy efficient, since the hot water is continuously circulated whether or not it is needed. 
         [0005]    Some other systems use a separate heater and water tank at the point of use, so that a small tank of hot water is always available at the tap or shower. While such systems deliver hot water immediately at the point of use, making them convenient for the household user, they heat the water continuously, which is not energy efficient, since many users are not home during the day, do not use hot water at night while they are sleeping, and typically only require instant hot water at one or two occasions during the day. 
         [0006]    Most household users have a fairly clear idea of when they need to use hot water. For example, someone who works a 9-to-5 job is not home during the day; heating the water during that time is wasteful and unnecessary. Also, most people take a shower at the same time each day; thus, hot water in large quantities may only be needed at a particular time each day, and not needed at any other time. 
         [0007]    A need therefore exists for a system and method of providing pre-heated water to the hot water tap only when actually needed by the user. 
       SUMMARY OF THE INVENTION 
       [0008]    An object of the present invention is to provide a hot water system that uses less energy than prior art hot water systems and prevents wasted water and energy. 
         [0009]    Another object of the present invention is to provide a hot water system that provides instant hot water on demand. 
         [0010]    Another object of the present invention is to provide a hot water system that adapts to the user&#39;s actual usage patterns. 
         [0011]    Another object of the present invention is to provide a hot water system that only heats the water when the user is likely to require hot water. 
         [0012]    Another object of the present invention is to provide a hot water system that can be controlled by a smartphone or other mobile device. 
         [0013]    In one of its embodiments, the present invention is a hot water system that comprises a heat storage device, a heater, a controller that controls the heater, the heat storage device, or both, and a communications interface that enables the controller to communicate wirelessly with a smartphone, tablet, or other mobile device. The heat storage device may be a heat capacitor, a hot water tank, or any other heat storage or hot water storage device known in the art. In the preferred embodiment, the heat storage device is capable of storing or heating enough hot water so as to meet a typical anticipated need. The heater may be any type of water heater known in the art, as long as it can be controlled by the controller. 
         [0014]    In one embodiment, the present invention also comprises a time and temperature monitor that analyzes water usage data. Such a time and temperature monitor may measure water flow rate, water pressure, timing of water use, quantity of water used, water temperature, and any other parameters relevant to a hot water system. The water usage data is then preferably used to predict future hot water use, and to deactivate the heater when hot water is unlikely to be required, while activating it when hot water is likely to be required. 
         [0015]    In another embodiment, the present invention enables a user to input a hot water usage pattern into the controller, preferably (but not necessarily) inputting times when hot water is likely to be required, times when hot water is not likely to be required, approximate amounts of hot water required, and any other parameters relevant to hot water use. This hot water usage pattern is then preferably used to activate the hot water heater when needed and to prepare a sufficient quantity of hot water so that the hot water flows instantly when the tap is turned on. The hot water usage pattern is preferably also used to deactivate the hot water heater when not needed—for example, when the user is at work during the day. 
         [0016]    In another embodiment, the present invention comprises a sensor that detects activity that is likely to correlate to a need for hot water, which triggers the hot water heater to turn on. The sensor may be a motion detector (to detect motion in the kitchen/bathroom), a light sensor, a sensor connected to a door to detect when it is opened, a GPS sensor on the user&#39;s smartphone that triggers the smartphone to turn on the hot water heater when the user approaches the house, and so on. The sensor may also detect activity that is likely to correlate to a lack of need for hot water and trigger the hot water heater to turn off. For example, the hot water heater may turn off when the GPS sensor on the user&#39;s smartphone shows that the user is further than a predetermined distance from the house; or a sensor connected to the user&#39;s bed may be triggered when the user is in bed (and therefore unlikely to require hot water). 
         [0017]    The present invention may comprise any combination of manual control, learned behavior, and sensors, or all of the above. 
     
    
     
       LIST OF FIGURES 
         [0018]      FIG. 1  shows a diagram of one embodiment of the system of the present invention. 
           [0019]      FIG. 2  shows a flowchart of one embodiment of the system of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0020]    The present invention is a heat storage system and method for hot water systems that is programmable or controllable by the user to only heat the water when actually needed. In one embodiment, the user can control the heat storage system by their smartphone  120 , via wi-fi, Bluetooth, or a cellular connection  130 . In another embodiment, the heat storage system learns the user&#39;s water usage patterns and automatically heats the water only when the user is likely to need it and only to the temperature the user is likely to want. In another embodiment, the user can pre-program the system to heat the water to the desired temperature when needed. The system can also comprise a sensor to detect the presence of people in the house, and only heat the water when people are present in the house, in the same room as the tap or shower, or in the near vicinity of the tap or shower. In the preferred embodiment, the heat storage system is installed at the point of use—i.e. immediately upstream from the water tap or shower. Several such systems may therefore be used—one in the kitchen, one in the shower, and so on. Alternately, one system may be used for the entire house or apartment. 
         [0021]    As shown in  FIG. 1 , the preferred embodiment of the present invention is a programmable water heat storage system and method controllable by a smartphone  120 . A user can input the desired hot water heating patterns into the system by using a smartphone  120 —preferably with a special app installed. Other input devices may also be used, such as a conventional cell phone, a tablet, an Internet-connected computer, or a dedicated remote control. The data is then transmitted to the microcontroller  140  via RF, wi-fi, Bluetooth, or any other data transmission methods known in the art  130 . The microcontroller  140  then transmits commands to the heater  160  and to the heat/energy storage and transfer device  150 , activating them at the desired time and letting them run until the water reaches the desired temperature. The heated water is then provided to the point of use  110  (i.e. the tap or shower). 
         [0022]    Alternately, as also shown in  FIG. 1 , a time and temperature monitor  100  continuously analyzes the user&#39;s water usage patterns—the amount of water demanded, the temperature of the water, the time and duration of water demand, and any other parameters that pertain to water use. The time and temperature monitor  100  then transmits the data to the microcontroller  140 , which uses this data to learn the user&#39;s water usage patterns and to predict future water usage patterns based on historical data. For example, if the user takes a 20-minute hot shower at a temperature of 80° F. every morning at 7 am, the time and temperature monitor  100  can detect that pattern, send it to the microcontroller, and have the microcontroller  140  predict that 80° F. water will be needed for at least 20 minutes at 7 am the next day. The microcontroller  140  then transmits commands to the heater  160  and to the heat/energy storage and transfer device  150 , activating them in advance of the 7 am time to allow sufficient time for the water to heat to the desired temperature, and making sure that enough hot water is stored to allow for a 20-minute shower. 
         [0023]    The heater can be any water heater known in the art, as long as it is controllable by a microcontroller. The heat/energy storage and transfer device can be any device known in the art that can store sufficient heat energy to enable water to be heated to a temperature that is typically required in normal household hot water use. The heat/energy storage and transfer device can store heat energy (i.e. a heat coil) or can store actual hot water (for example, in a small hot water tank). It must also be controllable by a microcontroller. 
         [0024]      FIG. 2  shows a flowchart view of the preferred embodiment of the present invention. Data from a flow sensor  200 , pre-programmed temperature settings  210 , learned behavior  240 , or user selections are input into the microcontroller  230  (labeled as MCU on the chart), which sends a command to the heater  260 . The heat energy then goes to the heat capacitor  220 . A temperature measurement device such as a thermocouple, a thermometer, or any other temperature measurement device known in the art, monitors the temperature of the heat capacitor  220 , and sends data to the microcontroller  230 ; the microcontroller  230  then can use the temperature data to control the heater  260  and to shut it off when the desired temperature is reached. 
         [0025]    It is to be noted that while the figures show learned behavior, preprogrammed temperature settings, and real-time user selections all used as input methods for the microcontroller, the invention can use only learned behavior and no user selections or pre-programmed settings, only user selections and no learned behavior or pre-programmed settings, only pre-programmed settings and no user selections or learned behavior, or any combination of those input methods. The invention can also use sensors to detect the presence of people in the house or in the near vicinity of the tap or shower, sensors to detect the opening or closing of a bathroom or kitchen door, a light sensor to detect when the light is turned on in the kitchen or bathroom, a sensor to detect when the user is in bed and therefore unlikely to use hot water, or any other sensors that can indicate the likelihood of a user desiring hot water at any given point in time. Those sensors may be used exclusively or in combination with any of the other input methods shown in  FIG. 2 . 
         [0026]    The system may also comprise an off switch to enable the user to shut it off manually when not needed—for example, when the user is going out of town for prolonged periods of time and hot water is not required. This will result in further energy savings.