Abstract:
A water heater which includes a tank ( 60 ) with a water inlet ( 64 ) and outlet ( 26 ). At least one divider ( 18 ) for dividing the tank into a plurality of chambers ( 12 ), ( 14 ) with adjacent chambers being arterial ( 28 ). A first chamber ( 14 ) is connected to the outlet and another one of the chambers ( 12 ) is connected to the inlet. Heating means ( 20 ) may be located in some or all of the chambers. The dividers may be oriented vertically or horizontally ( 18 ). They may be movable and of specific construction including apertures ( 28 ) therein for arterial connection to adjacent chambers which apertures may contain flow control thermostats. They may be insulated to reduce heat transfer between compartments. Where displacement is via density/temperature changes in a compartment, stops may be provided to limit the travel of the dividers/partitions. Sacrificial protection ( 74 ) may be provided for the tank.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application claims priority under 35 USC §119(e) of Provisional Patent Application bearing Ser. No. 61/015,457, filed on Dec. 20, 2007, the contents of which are hereby incorporated by reference. 
     
    
     TECHNICAL FIELD 
       [0002]    The present invention relates to the field of hot water tanks. 
       BACKGROUND 
       [0003]    In conventionally constructed hot water heaters there is provided an insulated cylindrical metal tank, in which water to be heated is stored. All of the stored water is heated to the desired temperature. The temperature is then maintained at the desired level throughout the entire tank. The heating cycles are controlled via a mechanical thermostat with little or no duty cycle control capabilities. Once the water temperature within the tank reaches a level that is below the desired temperature, the thermostat is turned on and the heating cycle begins and is ended when the set temperature is attained. 
         [0004]    Also, conventional tanks generally provide an inlet and an outlet for incoming cold water and outgoing hot water flow. When a hot water tap is opened, hot water flows out of the tank to the tap or appliance being used and cold water then is allowed to flow into the tank and is mixed in with the hot water. The entering of cold water in the water heater results in a cooling effect on the remaining hot water and subsequently reduces the usable hot water capacity of the tank. 
         [0005]    Therefore, there is a need for maintaining the usable hot water capacity of a water heater. 
       SUMMARY 
       [0006]    According to a broad aspect, there is provided a water heater comprising: a tank having an inlet for entering cold water and an outlet for exiting hot water; at least one divider located inside the tank, the at least one divider dividing the tank into a plurality of chambers, two adjacent ones of the plurality of chambers being fluidly connected, a first one of the plurality of chambers being connected to the outlet and containing the hot water, and a last one of the plurality of chambers being connected to the inlet; at least one heating element located in the first one of the plurality of chambers; and a control unit for adjusting a temperature of the at least one heating element. 
         [0007]    The divider may be movable within the tank in order to adjust the volume of hot water contained in the tank. Alternatively, the divider may have a fixed position within the tank and a cold water chamber is provided with a heating element in communication with the control unit. By turning on the heating element of the cold water chamber, the volume of available hot water is increased. The divider may be insulated to provide better heat separation. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    Further features and advantages of the present invention will become apparent from the following detailed description, taken in combination with the appended drawings, in which: 
           [0009]      FIG. 1  illustrates a multi-chamber water heater comprising a single moveable divider defining two chambers, in accordance with an embodiment; 
           [0010]      FIG. 2  illustrates a multi-chamber water heater comprising three fixed dividers and four heating devices, in accordance with an embodiment; and 
           [0011]      FIG. 3  illustrates a multi-chamber water heater comprising one moveable divider, two fixed dividers, and three heating elements, in accordance with an embodiment. 
       
    
    
       [0012]    It will be noted that throughout the appended drawings, like features are identified by like reference numerals. 
       DETAILED DESCRIPTION 
       [0013]      FIG. 1  illustrates one embodiment of a multi-chamber water heater  10  comprising two chambers  12  and  14 . 
         [0014]    The multi-chamber water heater  10  includes a tank  16 , a moveable divider  18 , a heating element  20  and a control unit  22 . The moveable divider  18  divides the tank  16  into the two chambers  12  and  14 : the first chamber  12  for cold water entering by a cold water inlet  24  and a second chamber  14  for hot water exiting the tank  16  by a hot water outlet  26 . The hot water chamber  14  includes a heating element  20  for heating the water. The moveable divider  18  moves vertically inside the tank to adjust the volume of the hot water chamber  14 . Displacement means are provided to allow for the displacement of the moveable divider  18 . The volume of the hot water chamber  14  is controlled by the position of the moveable divider  18  inside the tank  16 . The control unit  22  controls the heating element  20  present in the hot water chamber  14  to adjust the temperature of the hot water and may be used to displace the moveable divider  18  along the tank. 
         [0015]    The moveable divider  18  is used to eliminate or reduce the undesired mixing of incoming cold water with the hot water stored within the tank  16  in order to maximize user comfort and energy efficiency, and reduce energy costs. This moveable divider  18  is insulated in order to prevent the mixing of heated and cold liquid stored within the tank  16 . Preventing the mixing of hot and cold liquid within the tank  16  serves to eliminate the cooling of the hot liquid when the cold water flows into the tank  16  during use. Eliminating this cooling effect increases the overall capacity of usable hot liquid stored within the tank  16 . This also increases the overall efficiency of the system and therefore helps to reduce energy costs. The use of the moveable divider  18  reduces the unneeded amount of water being heated and maintained at set temperatures, therefore reducing energy use and costs. 
         [0016]    In one embodiment, the moveable divider&#39;s  18  movement within the tank  16  dynamically controls the hot and cold water proportions stored within the tank  16 . The dynamic movement of the moveable divider  18  is caused by variations in density of hot water which is in turn controlled by the heating and cooling cycles within the tank  16 . Any material or combination of material which renders the moveable divider  18  neutrally buoyant such that its movement is only caused by the changes in water density can be used. Water bleeder holes cross the moveable divider  18 . When the volume of hot water has to be increased, the temperature of the hot water is increased via the heating element  20 . The volume of the hot water contained in the hot water chamber  14  increases as a result of the increased temperature. As the water is heated, there is a change in density, which causes the divider  18  to move downwards. The volume of cold water passing from the cold water chamber  12  to the hot water chamber  14  corresponds to the further needed hot water volume. The increase of the hot water chamber volume is equal to the surface area of the moveable divider  18  multiplied by the distance traveled by the moveable divider  18 . The temperature of the hot water is maintained at an appropriate level to have the desired volume of hot water. 
         [0017]    In another embodiment, the dynamic movement of the moveable divider  18  is performed mechanically by using a motor driven track system controlled by the control unit  22 , which allows the moveable divider  18  to travel up and down inside the tank  16 . It should be understood that any mechanical means allowing the displacement of the divider  18  within the tank  16  can be used. 
         [0018]    A further embodiment includes the use of a thermostatic mixing valve such as the type found in a vehicle cooling system, mounted onto the moveable divider in such a way as to allow water flow from one chamber to the other once a particular temperature is reached. 
         [0019]    In one embodiment, the moveable divider  18  has substantially the same cross-sectional shape as that of the internal part of the tank, and the surface area of the cross section of the moveable divider  18  is slightly inferior to that of the cross section of the internal part of the tank. Alternative cross-sections and shapes are possible for the moveable divider  18 , as long as a separation is provided between the hot water and the cold water. 
         [0020]    In one embodiment, the moveable divider  18  is made of a material that is not affected by temperature fluctuations and the moveable divider  18  can be maintained stable within the tank  16 . Alternatively, the moveable divider  18  can be balanced by adding weights. 
         [0021]    In one embodiment, stoppers  24  are placed along the moveable divider&#39;s  18  path inside the tank  16  to ensure a minimum hot water chamber  14  volume and a minimum cold water chamber  12  volume. 
         [0022]    In one embodiment, the control unit  22  comprises an on/off button to control the heating element  20  which can only be in two states, namely a non-heating state and a heating state in which it heats water at a non-varying predefined temperature. Alternatively, the temperature of the heating element  20  can take any value between zero and a maximum temperature. Any control unit or module for controlling the temperature of any heating element or device can be used. 
         [0023]    In one embodiment, the control unit  22  includes a CPU controller for controlling heating and cooling cycles. At least one temperature sensor  30  is placed inside the tank  16  to inform the CPU controller about the water temperature. Furthermore, this control unit  22  comprises a memory for storing heating period information which include heating period preferences and/or historical usage patterns, for example, in order to more precisely and more efficiently control heating and cooling cycles. The control unit  22  controls the available volume of hot water, as well as its temperature. The control unit&#39;s  22  memory may also include data such as calendar events, holidays, homecomings, seasonal changes, etc. 
         [0024]    In one embodiment, the multi-chamber water heater  10  is provided with a means for remotely controlling the CPU of the control unit  22  and/or updating the memory of the control unit  22 . This is achieved via wired and/or wireless means of communication and/or data transfer. The updating and/or control may be completed by a third party such as an energy service provider. The service provider has the capability of updating the controller unit&#39;s  22  memory with new heating period preferences, further increasing the level of energy efficiency and cost savings. The new heating period preferences can be determined according to peak energy demand period information, for example. The new peak energy demand period information relates to the time periods during which the electricity or other energy sources are the most consumed. The cost of the energy source may be dependant on the global consumption. For example, the cost can be higher in the morning than at night. In this case, the control unit chooses the time periods during which the water is heated on the basis of the peak energy demand period information and of historical usage patterns. Doing so, the control unit avoids peak energy demand periods which results in cost savings. Alternatively, the updating of the control unit  22  can be done manually. For example, a computer can be connected to the control unit and data can be transferred from the computer, or a user can input data directly into the control unit  22  via an interface. 
         [0025]    In one embodiment, the CPU controller is programmed to eliminate the possibility of causing new peak energy demand periods, in the case of mass adoption of the present multi-chamber water heater. A first method for avoiding new peak energy demand periods is to make the heating cycles last over a longer period of time for a one week period every month, for example, thus making energy consumption more linear. A second method consists in introducing fixed and/or variable time slots at which the multi-chamber water heater  10  initiates and completes the heating cycles. A third method consists in monitoring the unit&#39;s supply voltage and/or current in order to detect lower levels willingly or unwillingly caused by the energy service provider during extreme weather conditions, thus equating this phenomenon to a peak period. 
         [0026]    In one embodiment, the multi-chamber water heater  10  has the ability to modify its behaviour upon resumption of electrical service following a power outage. This capability serves to eliminate harmful phenomena such as power surges that often occur when electrical demand is too high upon resumption of electrical service. 
         [0027]    In one embodiment, the multi-chamber water heater  10  provides substantial water savings by virtue of the fact that the set temperature is at a lower value than conventional set temperatures, for example 132° F. rather than 145° F. The multi-chamber water heater  10  causes less cold/hot water mixing in order to provide for example, a comfortable shower temperature of 104° F. The set temperature of 132° F. is made possible by the use of the moveable divider  18  which prevents cold and hot water mixing during regular water consumption. 
         [0028]    A further added benefit is an increased level of security by reducing the risk of burns related to high temperature settings on conventional hot water heaters. For example the burn time, defined as the maximum duration until injury, at a set temperature of 145° F. is 3 seconds for an adult and 1.5 seconds for a child under the age of 5 whereas the burn time at a set temperature of 132° F. is 30 seconds for an adult and 10 seconds for a child. Statistically, the risk of burns associated to the present multi-chamber water heater  10  can be reduced by a factor of 10. 
         [0029]    In another embodiment, the multi-chamber water heater  10  comprises an additional heating element located in the cold water chamber  12 . The additional heating element is controlled by the control unit  22 . The role of this second heating element is to kill bacteria and limit its reproduction in the cold water chamber. Periodically, the outlet of the multi-chamber is closed and the second heating element is heated at a temperature suitable for killing the bacteria contained in the cold water chamber. 
         [0030]    In one embodiment, the position of the moveable divider is controlled by adjusting the density of both the hot and cold water. This is done by adjusting the relative temperatures of the cold and hot water via the heating elements present in the cold water chamber  12  and the hot water chamber  14 , respectively. 
         [0031]    In one embodiment, when the multi-chamber water heater  10  comprises a heating element in the cold water chamber  12 , the divider  18  can have a fixed position in the tank  16 . In this case, the cold water chamber  12  and the hot water chamber  14  each have a fixed volume. By heating the water contained in the cold water chamber  12 , the total volume of hot water available to the user is increased. 
         [0032]    In one embodiment, the hot water chamber  14  is provided with blending means for blending the hot water. When entering the hot water chamber  14 , cold water is blended with the hot water. Thus, the temperature of the water contained in the hot water chamber  14  is uniform. In addition to increasing the effectiveness of the heating cycle, the level of comfort is increased since the hot water available for the user is set at a uniform temperature. If the multi-chamber water heater  10  is provided with an additional heating element in the cold water chamber  12 , blending means can also be provided in the cold water chamber  12 . 
         [0033]      FIG. 2  illustrates one embodiment of a multi-chamber water heater  50  having four fixed volume chambers  52 ,  54 ,  56 , and  58 . The multi-chamber water heater  50  comprises a tank  60  and three fixed dividers  62 . The tank  60  is provided with an inlet  64  for entering cold water and an outlet  66  for exiting hot water. The three fixed dividers  62  have a fixed position within the tank  60  and divide the tank  60  into four chambers  52 ,  54 ,  56 , and  58  having a fixed volume. At least one water bleeder hole crosses  68  each fixed divider. Water can pass from one chamber to an adjacent chamber through the water bleeder hole  68 . Each chamber  52 ,  54 ,  56 ,  58  is provided with a heating element  70 , each being controlled by a control unit  72 . 
         [0034]    The control unit  72  controls the volume and the temperature of the hot water by controlling the heating elements  70 . If a small volume of hot water is required, only the heating element  70  of the top chamber  52  is heated to a desired temperature. If more hot water is required, the control unit  72  increases the temperature of the heating element of the adjacent chamber  54  to the desired temperature. If a maximum volume of hot water is required, the heating elements  70  of all of the chambers  52 ,  54 ,  56 , and  58  are heated at a desired temperature and each chamber  52 ,  54 ,  56 ,  58  contains hot water. 
         [0035]    When hot water exits the multi-chamber water heater  50 , cold water enters the chamber  58  located at the bottom of the tank  60 . A volume equivalent to the volume of the entering cold water passes from one chamber  54 ,  56 ,  58  to an above chamber  52 ,  54 ,  56  using the water bleeder holes  68  of the fixed dividers  62 . Water entering a chamber mixes with the remaining water present in the chamber. In the case of cold water entering a hot water chamber, cold and hot water may be mixed and the temperature of the mixed water is then brought to a desired temperature by the heating element  70 . 
         [0036]    In one embodiment, the control unit  72  comprises a thermostat which controls the temperature of the heating elements  70 . By turning-off the heating element  70  of a chamber  52 ,  54 ,  56 ,  58 , the corresponding chamber  52 ,  54 ,  56 ,  58  becomes a cold water chamber containing cold water. In one embodiment, the user directly sets the temperature of each heating element  70 . In another embodiment, the user enters the volume of desired hot water into the control unit  72  via an interface. The control unit  72  is adapted to turn on the appropriate heating elements  70  in order to obtain the desired hot water volume. 
         [0037]    In another embodiment, the control unit  72  is provided with a CPU and is adapted to perform some or all of the functions described above with respect to the control unit  22 . 
         [0038]    In one embodiment in which the tank  60  is made of metal, the multi-chamber water heater  50  is provided with an anode rod  74  in order to protect against corrosion of the tank  60 . The anode rod  74  extends across the chambers  52 ,  54 ,  56 , and  58  and can be made of aluminum or magnesium, for example. The anode rod  74  is also referred to as a sacrificial anode since it dissolves slowly and sacrifices itself to protect the metal tank  60 . 
         [0039]    While the present embodiment includes four chambers  52 ,  54 ,  56 , and  58 , it should be understood that the number and the volume of the chambers may vary. For example, the volume of the chamber  52  may be greater than that of the other chambers  54 ,  56 , and  58 . Alternatively, the dividers are positioned in the tank  60  such that the chambers  52 ,  54 ,  56 , and  58  have a same volume. The multi-chamber water heater may comprise any number of chambers as long as it comprises at least two chambers separated by a divider. 
         [0040]      FIG. 3  illustrates one embodiment of a multi-chamber water heater  100  combining two fixed dividers  102  and  103  and one moveable divider  104 . The multi-chamber water heater  100  comprises a tank  103 , the two fixed dividers  102  and the moveable divider  104 . The tank  60  is provided with an inlet  106  for entering cold water and an outlet  108  for exiting hot water. The two fixed dividers  102  have a fixed position within the tank  106  while the moveable divider  104  can move within the tank  106 . The three dividers divide the tank  106  into four chambers  110 ,  112 ,  114 , and  116  of which the two top chambers  110  and  112  have a fixed volume and the two bottom chambers  114  and  116  have a varying volume. At least one water bleeder hole  118  crosses each divider  102 . Water can pass from one chamber  112 ,  114 ,  116  to an adjacent chamber  110 ,  112 ,  114  through the water bleeder holes  118 . 
         [0041]    In one embodiment, the three top chambers  110 ,  112 , and  114  are provided with a heating element  120 , each being controlled by a control unit  122 . Alternatively, the bottom chamber  116  may also be provided with a heating element. By controlling the temperature of the heating elements  120  and the position of the moveable divider  104 , the control unit  122  controls the temperature and the volume of the hot water contained in the tank  106 . Stoppers  124  may be provided to define a minimum volume for the variable-sized chambers  114  and  116 . 
         [0042]    In one embodiment, the dynamic movement of the moveable divider  104  is caused by variations in water density which is in turn controlled by the heating and cooling cycles within the tank  106 . In this case, a temperature sensor in communication with the control unit  122  can be used to obtain a better control of the temperature of water in the chamber  114 , which in turn offers a better control on the volume of the chamber  114 . In another embodiment, the dynamic movement of the moveable divider  104  is performed mechanically by using a motor driven track system which allows the moveable divider to travel up and down inside the tank. 
         [0043]    In another embodiment, at least one thermostatic mixing valve, such as the type found in a vehicle cooling system, is mounted onto the divider  102 ,  104  in such a way as to allow water flow from one chamber  112 ,  114 ,  116  to the other chamber  110 ,  112 ,  114  once a particular temperature is reached. 
         [0044]    While the multi-chamber water heater  100  includes four chambers  110 ,  112 ,  114 , and  116 , it should be understood that the number of fixed and moveable dividers, and the volume of the chambers, may vary. 
         [0045]    In one embodiment, the multi-chamber water heater  100  is provided with at least one temperature sensor to monitor the temperature of water. For example, four temperature sensors in communication with the control unit  122  are used to determine the temperature of water in the four chambers  110 ,  112 ,  114 , and  116 . 
         [0046]    While only  FIG. 2  illustrates a multi-chamber water heater  50  comprising an anode rod  74 , it should be understood that an anode rod can be provided within any multi-chamber water heater of which the tank is made of metal. 
         [0047]    In one embodiment, the holes in the dividers necessary for the anode rod are substantially larger than the diameter of the anode rod. These holes allow water to cross the dividers and act as water bleeder holes. In another embodiment, the hole for the anode rod is substantially hermetically closed such that no water can pass through this hole. In a further embodiment, the anode rod acts as a guide for the moveable divider and prevents an unwanted rotation of the moveable divider during its displacement. Alternatively, each chamber can be provided with a corresponding anode rod. It should be understood that any corrosion protection means can be used. 
         [0048]    In one embodiment, the fixed divider has substantially the same cross-sectional shape and surface area as those of the internal part of the tank. Alternative cross-sections and shapes are possible for the fixed divider, as long as a separation is provided between the hot water and the cold water. 
         [0049]    While the figures illustrate the tank with the hot water provided in the upper chamber and the cold water provided in the lower chamber, the tank may be configured to have the two chambers side-by-side, or to have the cold water in the upper chamber and the hot water in the lower chamber. 
         [0050]    In one embodiment, the moveable and/or fixed dividers are made of a waterproof material in order to prevent an undesired mixing of cold and hot water. For example, hydrophobic material can be used. In another embodiment, the moveable and/or fixed dividers are made of thermal insulating material to reduce the cooling of the hot water. For example, the dividers can be made of polystyrene or rubber. 
         [0051]    It should be understood that any electrical and/or mechanical, and/or software means known by a person skilled in the art to displace a moveable divider within the tank can be used and falls within the scope of the invention. Any means for fluidly connecting two adjacent chambers can also be used. The connection can be made through the moveable or fixed divider. Alternatively, the connection can be made external to the fixed or moveable divider. For example, a hole can cross the moveable or fixed divider. A valve can be added to prevent a mixing of cold and hot water when not required. 
         [0052]    It should be understood that any heating element adapted to heat water and any temperature sensor adapted to determine the temperature of water can be used. 
         [0053]    While the present description refers to a single heating element/device per chamber, a person skilled in the art will understand that more than one heating element/device may be located in a chamber. 
         [0054]    In one embodiment, the multi-chamber water heater is provided in similar outer dimensions and connections such as the ones found on conventional water heaters. In one embodiment, the multi-chamber water heater requires the same electrical and/or other energy sources as the ones found on conventional water heaters. For example, the heating element can be an electrical heating element, a gas burner, etc. 
         [0055]    The embodiments of the invention described above are intended to be exemplary only. The scope of the invention is therefore intended to be limited solely by the scope of the appended claims.