Abstract:
A method of storing water at two temperatures, the method comprising: providing a tank divided into first and second chambers; storing water in the first chamber at a first temperature; storing water in the second chamber at a second temperature; heating water in the second chamber when the second temperature is below a predetermined second value; pumping water from the second chamber to the first chamber when the first temperature is below a predetermined first value, the first values being less than the second value; and permitting water flow from the first chamber to the second chamber while pumping water from the second chamber to the first chamber.

Description:
RELATED APPLICATION 
       [0001]    This application is a divisional of U.S. application Ser. No. 11/458,495, filed Jul. 19, 2006, the entire contents of which are incorporated herein by reference. 
     
    
     BACKGROUND 
       [0002]    The present invention relates to heating water and maintaining water at two different temperatures in a single tank. 
       SUMMARY 
       [0003]    In one embodiment, the invention provides a water heating apparatus including a tank divided into first and second chambers, wherein water in the first chamber has a first temperature and water in the second chamber has a second temperature. The water heating apparatus also includes a first outlet for supplying water from the first chamber to a first recipient, a first thermostat configured to measure the first temperature, a second thermostat configured to measure the second temperature, means for heating water in the second chamber, a pump having a pump inlet in fluid communication with the second chamber and a pump outlet in fluid communication with the first chamber, and a controller configured to initiate pumping of water from the second chamber to the first chamber when the first thermostat indicates the first temperature is below a predetermined first value. The controller is also configured to initiate heating of water in the second chamber when the second thermostat indicates the second temperature is below a predetermined second value, the second value being greater than the first value. 
         [0004]    In another embodiment the invention provides a water heating and distribution system including a tank divided into first and second chambers, wherein water in the first chamber has a first temperature and water in the second chamber has a second temperature. The water heating and distribution system also includes a first outlet, a first recipient for receiving water from the first chamber via the first outlet, a first thermostat configured to measure the first temperature, a second thermostat configured to measure the second temperature, means for heating water in the second chamber, a pump having a pump inlet in fluid communication with the second chamber and a pump outlet in fluid communication with the first chamber, and a controller configured to initiate pumping of water from the second chamber to the first chamber when the first thermostat indicates the first temperature is below a predetermined first value. The controller is also configured to initiate heating of water in the second chamber when the second thermostat indicates the second temperature is below a predetermined second value, the second value being greater than the first value. 
         [0005]    In another embodiment the invention provides a method of storing water at two temperatures, the method including providing a tank divided into first and second chambers, storing water in the first chamber at a first temperature, storing water in the second chamber at a second temperature, and heating water in the second chamber when the second temperature is below a predetermined second value. The method also includes pumping water from the second chamber to the first chamber when the first temperature is below a predetermined first value, the first values being less than the second value, and permitting water flow from the first chamber to the second chamber while pumping water from the second chamber to the first chamber. 
         [0006]    Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  is a perspective view of a water heating and distribution system embodying the present invention. 
           [0008]      FIG. 2  is a partial cross-sectional view of the water heating and distribution system of  FIG. 1 . 
           [0009]      FIG. 3  is a perspective view of a water heating and distribution system that is an alternative embodiment of the present invention. 
           [0010]      FIG. 4  is a perspective view of a water heating and distribution system that is an alternative embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0011]    Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless specified or limited otherwise, the terms “mounted,” “connected,” “supported,” and “coupled” and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings. Further, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings. 
         [0012]      FIGS. 1 and 2  illustrate a water heating and distribution system  10  embodying the present invention. The water heating apparatus  10  includes a tank  12  and a boiler  14  for heating water in the tank  12 . The tank  12  is defined in part by a generally cylindrical tank wall  15  that is preferably insulated to retain heat, and is divided into a first or lower chamber  16  and a second or upper chamber  18  by a baffle  20 . The baffle  20  is sealingly connected to the inner surface of the tank  12  about the perimeter of the baffle  20 . The baffle  20  is secured within the tank in a substantially horizontal configuration and is substantially flat. The baffle  20  also includes a plurality of apertures that permit fluid communication between the lower and upper chambers  16 ,  18 . A cold water inlet  23  supplies water to the lower chamber  16 . In some embodiments, the cold water inlet  23  could supply water to the upper chamber  18 . 
         [0013]    The tank  12  also includes a first or lower outlet conduit  30  for supplying water from the lower chamber  16 , and includes a second or upper outlet conduit  34  for supplying water from the upper chamber  18 . First and second recipients  32 ,  36  receive water via the lower and upper conduits  30 ,  34 , respectively, which is explained in greater detail below. Water can be drawn from either or both of the first and second outlet conduits  30 ,  34  independently. 
         [0014]    In the illustrated embodiment, the boiler  14  is configured to receive water from the upper chamber  18  via a boiler inlet conduit  40 , heat the water, and return the heated water to the upper chamber  18  via a boiler outlet conduit  42 . As explained in greater detail below, the boiler  14  only heats water in the upper chamber  18  when necessary. In alternative embodiments, the water in the tank  12  can be heated with an electric heating element positioned inside the tank, with a gas burner such as those found on conventional gas water heaters, by a conventional water heater, or by any other suitable means. The tank  12  includes a relief valve  43  near the top of the tank  12  to relieve excess pressure that may build within the tank  12  when water is heated. 
         [0015]    A pump  44  is connected to the upper chamber  18  via a pump inlet conduit  46 , and is connected to the lower chamber  16  via a pump outlet conduit  48 . The pump  44  transfers hot water from the upper chamber  18  to the lower chamber  16 . 
         [0016]    In the illustrated embodiment of  FIGS. 1-3 , a controller  50  is employed to control the heating of water in the upper chamber  18  and the pumping of water from the upper chamber  18  to the lower chamber  16 . The controller  50  maintains water in the lower and upper chambers  16 ,  18  at first and second temperatures, respectively. In the illustrated embodiment, the second temperature is greater than the first temperature. The controller  50  is connected to first and second thermostats  51 ,  52 . The first and second thermostats  51 ,  52  are connected to the tank  12  to measure the first and second temperatures, respectively. The controller  50  is also connected to the boiler  14  and the pump  44 . First and second values defining desired first and second temperatures are assigned to the first and second thermostats  51 ,  52 , respectively. The controller  50  monitors the first and second temperatures with the first and second thermostats  51 ,  52 , and controls heating and pumping as described below to maintain the first and second temperatures at the first and second values. 
         [0017]    When the second thermostat  52  indicates the second temperature has dropped below the assigned second value, the controller  50  sends a signal to the boiler  14  to cycle and heat water in the upper chamber  18 . When the second temperature has met the second value, the controller  50  sends a signal to the boiler  14  to cease cycling and heating. 
         [0018]    When the first thermostat  51  indicates the first temperature has dropped below the assigned first value, the controller  50  sends a signal to the pump  44  to transfer warmer water from the upper chamber  18  to the lower chamber  16 . When water is pumped from the upper chamber  18  to the lower chamber  16 , water from the lower chamber  16  flows through the apertures in the baffle  20  into the upper chamber  18 . When the first temperature has met the first value, the controller  50  sends a signal to the pump  44  to cease pumping. 
         [0019]    In some embodiments, it may be more economical to operate the pump  44  continuously, rather than turn it on and off as required. In these embodiments, a control valve  55  may be included in the pump inlet conduit  46  (see  FIG. 3 ) and connected to the controller  50 . The control valve  55  can allow water to be pumped from the upper chamber  18  to the lower chamber  16  as described above, or can alternatively allow water to be drawn from the lower chamber  16  via conduit  56  and pumped back into the lower chamber  16  to circulate or stir water in the lower chamber  16 . Instead of turning the pump  44  on and off, the controller  50  can actuate the control valve  55  to determine whether water from the upper or lower chamber  18 ,  16  is supplied to the pump  44 , depending on the temperature requirements at that instant. 
         [0020]    The heating of water in the upper chamber  18  and the pumping of water from the upper chamber  18  to the lower chamber  16  occur independently. To minimize wasted energy, the controller  50  only activates the boiler  14  or the pump  44  when necessary. The controller  50  is preferably configured to have some tolerance to avoid constantly turning the boiler  14  and pump  44  on and off. For example, if the assigned first value is 140 F for the lower chamber  16 , the controller  50  may pump water from the upper chamber  18  into the lower chamber  16  until the first temperature reaches 142 F before turning off the pump  44 , and also may not turn the pump  44  on until the first temperature falls to 138 F. A similar principle could be applied to the upper chamber  18  and the boiler  14 . These values are only an example, and could be varied to minimize actuation of the boiler  14  and pump  44  while keeping the first and second temperatures within suitable ranges, depending on the requirements of the first and second recipients  32 ,  36 . 
         [0021]    When water is drawn from the first outlet conduit  30 , replacement water fills the lower chamber  16  from the cold water inlet. When water is drawn from the second outlet conduit  34 , replacement water enters the upper chamber  18  through the apertures in the baffle  20  from the lower chamber  16 , and replacement water fills the lower chamber  16  from the cold water inlet. The controller  50  is constantly monitoring the first and second temperatures and controlling heating and pumping to maintain the first and second temperatures, even when water is being drawn from either or both of the lower and upper chambers  16 ,  18 . 
         [0022]    The water heating apparatus  10  can be used in numerous applications, including potable water systems and hydronic heating systems.  FIGS. 1 and 2  illustrate a first application where potable water at a first temperature is required by the first recipient  32 , and potable water at a second, higher temperature is required by the second recipient  36 . An example of this type of application is a commercial kitchen where water at approximately 140 F, for example, is maintained in the lower chamber  16  and is intended for general purpose use, while water at approximately 180 F, for example, is maintained in the upper chamber  18  and is used by dishwashers and other sanitary applications. 
         [0023]      FIGS. 1 and 2  also illustrate the water heating apparatus  10  configured for use in a hydronic heating application. In this embodiment, the tank  12  includes a first inlet conduit  60  for supplying return water from the first recipient  32  to the lower chamber  16 , and includes a second inlet conduit  62  for supplying return water from the second recipient  36  to the upper chamber  18 . In this embodiment, the first and second recipients  32 ,  36  are first and second hydronic heating systems, respectively, wherein the first and second hydronic heating systems require water at different temperatures. 
         [0024]    The water heating apparatus  10  as illustrated in  FIGS. 1 and 2  can also be used in alternative embodiment to supply water to three recipients at three temperatures. This embodiment assumes that a third recipient  64  requires hot water directly from the boiler  14 , the second recipient  36  requires water at a lower temperature than the third recipient  64 , and the first recipient  32  requires water at a lower temperature than the second recipient  36 . In this embodiment, a third outlet conduit  66  is configured to supply water from the boiler  14  to the third recipient  64 . Water is maintained at the desired first and second temperatures in the upper and lower chambers  18 ,  16  as described above. In the event that the third recipient  64  is a hydronic heating system, a third inlet conduit  68  supplies water from the third recipient  64  to the boiler inlet conduit  40 . 
         [0025]      FIG. 3  illustrates an embodiment of the water heating and distribution system  10  where the tank  12  includes only the first outlet conduit  30  in the lower chamber  16  rather than first and second outlet conduits  30 ,  34 . This embodiment is configured to supply water to only the first recipient  32 , and assumes that the first recipient  32  requires water at a lower temperature than the boiler  14  can output while operating in an efficient manner. This embodiment is convenient if the first recipient requires water at 140 F, for example, and the boiler  14  is configured to output water at 180 F, for example. In operation, water enters the upper chamber  18  from the boiler  14  at 180 F, while water in the lower chamber  16  is maintained at 140 F as described above with respect to the embodiment illustrated in  FIGS. 1 and 2 . This allows the first recipient  32  to receive water at the desired temperature of 140 F, and allows the boiler  14  to operate in a temperature range for which it was intended. 
         [0026]    Also illustrated in  FIG. 3  is an embodiment where the first recipient  32  is a hydronic heating system that requires water at a lower temperature than what the boiler  14  is configured to output. Similar to the embodiment illustrated in  FIGS. 1 and 2 , the tank also includes a first inlet  60  for supplying return water from the first recipient  32  to the lower chamber  16 . 
         [0027]    In the illustrated embodiments in  FIGS. 1-3 , the tank  12  includes first and second outlet conduits  30 ,  34  and first and second inlet conduits  60 ,  62 . In some of the described embodiments, the tank  12  is lacking one or more inlet and/or outlet conduit. To lower manufacturing costs, the tank  12  is manufactured with the capacity to include both outlet conduits  30 ,  34  and both inlet conduits  60 ,  62 . In the event that an operator wishes to use the tank as described in the embodiments requiring less inlets and/or outlets, or change the manner in which the tank  12  is used, a plug may be applied to the tank  12  to replace the inlet and/or outlet conduits that will not be used. This allows a single tank to be manufactured that will satisfy a number of different applications. 
         [0028]      FIG. 4  illustrates another embodiment of a water heating and distribution system  110  according to the present invention. The water heating and distribution system  110  shown in  FIG. 4  is similar in many ways to the illustrated embodiments of  FIGS. 1-3  described above. Accordingly, with the exception of mutually inconsistent features and elements between the embodiment of  FIG. 4  and the embodiments of  FIGS. 1-3 , reference is hereby made to the description above accompanying the embodiments of  FIGS. 1-3  for a more complete description of the features and elements (and the alternatives to the features and elements) of the embodiment of  FIG. 4 . 
         [0029]      FIG. 4  illustrates the controller  150  connected to the first thermostat  51  and the pump  44 . The second thermostat  52  is connected to the boiler  114 . Similar to the embodiments of  FIGS. 1-3 , the controller  150  is employed to control the pumping of water from the upper chamber  18  to the lower chamber  16  when the first thermostat  51  indicates the first temperature has dropped below the assigned first value. In embodiments where the pump  44  is configured to operate continuously, the controller  150  is connected to the control valve  55  (as shown in  FIG. 3 ) and actuates the control valve  55  to determine whether water from the upper or lower chamber  18 ,  16  is supplied to the pump  44 , depending on the temperature requirements in the lower chamber  16  at that instant. 
         [0030]    In the illustrated embodiment of  FIG. 4 , the boiler  114  is not controlled by the controller  150 . Rather, the boiler  114  is configured to monitor the temperature of the water in the upper chamber  18  and heat the water in the upper chamber  18  when the second thermostat  52  indicates the second temperature has dropped below the assigned second value. When the second temperature has met the second value, the boiler  114  ceases cycling and heating of water from the upper chamber  18 .