Patent Publication Number: US-2022235968-A1

Title: Hot water tank with thermal mixing valve

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This Patent Application claims priority to and the benefit of U.S. National Stage patent application Ser. No. 16/345,139 filed on Apr. 25, 2019, International Patent Application No. PCT/US2017/058499 having an International filing date of Oct. 26, 2017, and U.S. Provisional Patent Application Ser. No. 62/413,132 filed on Oct. 26, 2016, which are incorporated by reference herein in their entirety. 
    
    
     FIELD OF INVENTION 
     Various configurations of the current invention relate generally to apparatus, systems, and methods for heating water. More particularly, the apparatus, systems, and methods relate to heating water in a water tank. Specifically, the apparatus, systems, and methods provide for heating water with a flow-through heating element located in a lower portion of a water tank. 
     BACKGROUND 
     Heated water is customarily provided in commercial aircraft lavatories for hand-washing purposes as well as in galleys for food and hot beverage preparation. There are a number of requirements for such systems that place many limitations on the designs which may be satisfactorily employed. A suitable system should provide needed heated water in as an efficient manner as possible. The amount of electrical power used for heating is limited because aircraft minimize the weight and cost of equipment and the use of less power helps accomplish these goals. It is also desired to keep repair and replacement expenses to a minimum. 
     One widely-used system accomplishes some of these goals but also has certain deficiencies. That system employs a tank containing two or more electrical heating elements immersed in water. A major shortcoming of that system is that a portion of water is in contact with the heater and is heated to a high temperature, possibly even boiling. This type of water heater may have the undesirable consequence that over time calcification or other impurities form mineral deposits on the heating elements. The deposits are poor thermal conductors and hence, overtime, additional power is required to heat the water. Further, the deposits hasten the need to replace the heating elements or the entire unit. What is needed is a better water heater. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The following figures are included to illustrate certain aspects of the present disclosure, and should not be viewed as exclusive embodiments. The subject matter disclosed is capable of considerable modifications, alterations, combinations, and equivalents in form and function, without departing from the scope of this disclosure. 
         FIG. 1A  illustrates a cross-section schematic view of an example first embodiment of a water heater with a flow-through heating element contained within a water tank that may incorporate the principles of the present disclosure. 
         FIG. 1B  illustrates a cross-section schematic view of an example second embodiment of a water heater with a flow-through heating element partially extending from a bottom portion of a water tank that may incorporate the principles of the present disclosure. 
         FIG. 2  illustrates a front view of a third embodiment of a water heater that may incorporate the principles of the present disclosure. 
         FIG. 3  illustrates a cross-section view of the third embodiment of a water heater that may incorporate the principles of the present disclosure. 
         FIG. 4  illustrates the water tank heating time of the third embodiment of a water heater that may incorporate the principles of the present disclosure. 
         FIG. 5  illustrates the water tank recovery time of the third embodiment of a water heater that may incorporate the principles of the present disclosure. 
         FIG. 6  illustrates another embodiment that is an exemplary method of heating water. 
         FIGS. 7A and 7B  illustrate a side profile view and a side cross-section view, respectively, of an embodiment of the water heater having a thermostatic mixing valve that may incorporate the principles of the present disclosure. 
         FIGS. 8A-8D  illustrate various cross-section views of the thermostatic mixing valve of  FIGS. 7A-7B . 
         FIG. 9  illustrates an embodiment of the thermal actuator utilized in the thermostatic mixing valve of  FIGS. 7A-7B . 
         FIGS. 10A-10B  illustrate an embodiment of the active mixing nozzle utilized in the thermostatic mixing valve of  FIGS. 7A-7B . 
     
    
    
     DETAILED DESCRIPTION 
     The present disclosure is related to water heater systems and, more particularly, to water heater systems with integrated thermal mixing valves. 
     The embodiments described herein provide a water heater system with an integral thermal mixing valve that helps maintain prevent scalding and/or maintains suitable water temperature. 
       FIG. 1A  illustrates a cross-sectional view of a first embodiment of a water heater  1  that includes a water tank  3  and a flow-through heating element  5 . Water tank  3  includes an input line  7  for receiving water into water tank  3  from a source of potable water that may be located remote from water heater  1 . Initially, when water tank  3  is empty, it may be filled by injecting water into it from input line  7 . 
     Water tank  3  further includes an output line  9  for dispensing heated water from water tank  3 . A bottom opening  4  of heating element  5  receives water from tank  3  so that it may be heated and/or reheated by flow-through heating element  5  as the water passes through an interior  2  of the heating element  5  and is re-injected into water tank  3  out of a top opening  6 . In some embodiments, flow-through heating element  5  may be a “Watlow” type of inline heater similar to flow-through/inline heaters manufactured by Watlow Electric Manufacturing Company. Additionally, a central tube of the heating element  5  may be a convoluted tube for more efficient heat transfer. 
     The subject matter of the present disclosure features a water heater  1  that includes using a flow-through heating element  5  near the base/bottom  14  of water heater  1 . In this configuration, heating element  5  is positioned so that its bottom opening  4  is near bottom wall  14  of water tank  3  and the rest of heating element  5  is internal to water tank  3 . As discussed below, heating element  5  may be placed in other positions as understood by those of ordinary skill in the art. Positioning heating element  5  near bottom of water tank  3  causes a pressure to be created to recirculate water in water tank  3 . This is because the introduction of heated water in this orientation results in the lighter heated water flowing upward toward the top of water tank  3  allowing cooler water to be displaced with this warmer water as the warmer water travels generally upward creating an upward pressure. The upward flowing of heated water that displaces cooler water may act to mix/churn water in water tank  3  so that the water may be more uniformly heated. In some configurations, a fan nozzle may be placed at the upper end of flow-through heating element  5  to disperse heated water as it leaves heating element  5 . Other configurations may utilize a directional nozzle at upper opening  6  to direct heated water in a particular direction as it leaves heating element  5  to create a desired circulation between warm and cool water within tank  3 . The present invention further utilizes recirculation, temperature differential, and uses positive pressure to heat water rather than simple contacting of a heating coil. The present invention further includes focusing on not increasing surface heating area to heat water but to, rather, running water through flow-through heating element  5  multiple times. Water tank  1  of  FIG. 1A  may be completely filled to maximize water that may be stored in water tank  1  or, alternatively, provide for a smaller water tank that can hold the same amount of water. 
     In some configurations, flow-through heating element  5  has an elongated interior channel that acts as a conduit allowing flow-through heating element  5  to heat water as it travels from an input end of this channel upward to an output end of the channel. This allows heating element  5  to act as a thermodynamic pump capable of moving water by temperature differences without requiring moving parts. Heating element  5  creates water velocities within water tank  3  that contribute to the reduction in biofilms and bacteria while promoting efficient thermal mixing within water tank  3 . Additionally, a pumping velocity changes as the temperature differential from the input end to the output end of flow-through heating element  5  reaches a maximum heating level. The improved thermal mixing also reduces the recovery time when hot water is drawn from water tank  3 . This is a significant improvement over prior art water heaters using tubular heating elements which over time may cause thermal stratification contributing to the breakdown of sanitary conditions inside prior art tanks. 
     In other configurations, flow-through heating element  5  may have one or more optional lower side openings  8  and one or more optional upper openings  10 . Lower openings  8  and or bottom opening  4  may allow cool water to enter heating element  5  near its bottom end and to be heated before exiting upper side openings  10  and/or top opening  6 . Those of ordinary skill in the art will appreciate that flow-through heating element  5  may have other openings in other positions and or may have elongated conduits extending from its main elongated interior channel to allow water to be pulled into heating element  5  from other places within tank  3  and for heated water to be distributed to other places within tank  3  to maintain an overall desired circulation pattern within tank  3  between cooler and warmer water. In some configurations, elongated conduits extending from its main elongated interior channel may branch out within water tank  3  with a tree shaped pattern. 
       FIG. 1B  illustrates another cross-sectional view of a second embodiment of a water heater  100  that also includes water tank  3 , a flow-through heating element  105 , water input line  7 , and output line  9 . This configuration additionally includes a recirculation line  11  connected to heating element  105 . Recirculation line  11  removes water from water tank  3  and sends it through a flow-through heating element  105  so that it is heated and/or re-heated and re-injected into water tank  3 . The present invention features a water heater  100  that includes using a flow-through heating element  105  similar to the heating element of  FIG. 1A  and that is near the base/bottom  14  of water heater  100 . For example, the heating element  105  may be positioned near the base  14  of water heater  100  so that a top end of heating element  105  extends into water tank  3  and a bottom end extends below bottom wall  14  of water tank  3  as illustrated in  FIG. 1B . In another configuration, heating element  105  may be positioned so that its top end is near bottom wall  14  of water tank  3  and the rest of heating element  105  is external to water tank  3 . As discussed above with reference to  FIG. 1A , heating element  105  may be positioned so that its bottom end is near bottom wall  14  of water tank  3  and the rest of heating element  105  is internal to water tank  3 . The heating element  105  may be placed in other positions as understood by those of ordinary skill in the art. As previously mentioned and described, positioning heating element  105  near bottom of water tank  3  causes a pressure to be created to recirculate water in water tank  3 . 
     As illustrated in  FIG. 1B , some configurations of water heater  100  may include an optional water pump  13  and a controller including control logic  15  to assist flow-through heating element  105  to control a speed that water is re-circulated through water tank  3 . For example, control logic  15  may evaluate temperatures recorded by different temperature sensors  17  at different locations within water tank  3 . During periods of high usage, temperature sensors  17  may detect generally lower temperatures prompting control logic  15  to run pump  13  at a higher speed and/or increasing heat that heating element  105  produces so that more water is heated. Optionally if different temperature sensors  17  record differing temperatures, it may be an indication that water within water tank  3  is not well circulated to, again, cause control logic  15  to run pump  13  at a higher speed and/or increase heat that heating element  105  produces. If temperature sensors  17  detect a temperature above an upper threshold amount, this may cause control logic  15  to turn off or reduce the heat that is produced by heating element  105  and/or to reduce the speed of pump  13  or to turn off pump  13 . 
     “Logic”, as used herein, includes but is not limited to hardware, firmware, software, and/or combinations of each to perform a function(s) or an action(s), and/or, to cause a function or action from another logic, method, and/or system. For example, based on a desired application or need, logic may include a software-controlled microprocessor, discrete logic such as an application-specific integrated circuit (ASIC), a programmed logic device, a memory device containing instructions, or the like. Logic may include one or more gates, combinations of gates, or other circuit components. Logic may also be fully embodied as software. Where multiple logical logics are described, it may be possible to incorporate the multiple logical logics into one physical logic. Similarly, where a single logical logic is described, it may be possible to distribute that single logical logic between multiple physical logics. 
     Water heater  100  may be produced sufficiently small so that it may be provided in commercial aircraft lavatories to provide hot water for such uses as washing hands and galleys for the preparation of hot beverages. Preferably, water heater  100  is made with rigid materials as understood by those of ordinary skill in the art. For example, water heater  100  may be produced using metallic pipes and couplings with water tank  3  formed with rigid metallic walls. In some configurations, water tank  3  may be a seamless plastic tank or a tank formed with other materials as understood by those of ordinary skill in the art. 
       FIGS. 2 and 3  illustrate a further embodiment of a water heater  200  that in some configurations may be used in aircraft. Similar to water heater  100  of  FIG. 1 , water heater  200  has a water tank  103 , a flow-through heating element  205 , a water input line  107 , a water output line  109 , a water recirculation line  111 , and a control logic  115 . Water heater  200  further includes a thermocouple  117 , a mixing valve  121 , and an optional water deflection plate  123 . Deflection plate  123  may optionally be a flat water deflection plate with side slots allowing a limited volume of water to past through while water on the other side of deflection plate adjacent to the slots is pulled by water passing through slots to create a churning action. This churning action promotes thermal mixing within the tank while reducing areas for biofilm development and reducing bacterial entrapment within water tank  103 . Recirculation line  111  exits near a bottom end of water tank  103  and is injected into a bottom end of heating element  205 . In other configurations, recirculation line  111  may exit water tank  103  at other different locations. 
     Mixing valve  121  may be added to the outlet line  109  external to water tank  103  to prevent personnel from being scalded by the high temperature of water exiting the system. Thus, the outlet line  109  may also serve as an inlet to the mixing valve  121 . As understood by those of ordinary skill in the art, mixing valve  121  may be a thermostatic mixing valve and may be adjustable. As illustrated, mixing valve  121  further includes a cold water input line  125  and an output line  127 . Mixing valve input line  125  is connected to input line  107  with a T-connector and line  129 . Hot water from the output line  109  of the water tank  103  is mixed with cool water from the input line  125  and output through output line  127 . Thus, mixing valve  121  may act as an anti-scalding valve that facilitates operation of the hot water tank above temperatures that promote bacterial growth, thus the maintaining of sanitary conditions while protecting hot water users from being scalded. 
     For example, hot water from water tank  103  after being heated above 131° F. (to reduce bacteria growth) enters mixing valve  121  and is mixed with cold water from input line  125  and exits output line  127  at a lower preset temperature for washing hands or beverage preparation. Keeping heated water in water tank  103  above 131° F. may prevent some bacterial growth and use of mixing valve  121  provides water supplied to the lavatories and galleys of a desired temperature between 95° F. to 115° F. to prevent personnel from being scalded. These temperatures may be consistently achieved during the draw and recovery period by the water heater  200  of  FIGS. 2 and 3 . It should be appreciated that the described temperatures and temperature ranges are one example and that the water tank  103  may be configured to store and supply water at other suitable temperatures and temperature ranges, for example, 125° F. 
     In other configurations, it may be desirable to heat water in tank  103  to a higher temperature than 131° F. to prevent other bacteria growth and to kill existing bacteria. As hot and cold water enters mixing valve  121 , in some configurations, an optional thermostat  131  in mixing valve  121  may sense the outlet water temperature. The thermostat  131  reacts by adjusting the incoming amounts of hot and cold water to maintain a stable output temperature. In some mixing valves, a mechanical adjustment of mixing valve  121  allows one to preset the maximum desired temperature. 
     Thermocouple  117  may sense temperature within water tank  103  and used by a control logic  115  to monitor and control the water temperature inside water tank  103 . The functionality of control logic  115  may be similar to the functionality of control logic  15  of  FIG. 1B  described above. Similar to the water heater  100  of  FIG. 1B , flow-through heating element  205  is located near the bottom of water tank  103 . Heating element  205  may be placed in other positions as understood by those of ordinary skill in the art. Heating element  205  is commonly a “flow-through” type of heating assembly because, in some configurations, heating element  205  flows water through its entire length during heating. Warmed water exiting heating element  205  creates a pressure head inside water tank  103  which contributes to the thermodynamic pumping action and thermal mixing of water within water tank  103 . As previously mentioned, this enables water heater  200  to maintain a generally uniform water temperature within water tank  103  above a predetermined value to maintain sanitary condition within water tank  103 . 
     Power to the flow-through water heater  205  is controlled to keep the temperature of water in tank  103  nearly constant during both the draw and idle periods.  FIG. 4  is an exemplary graph of the initial heating time of water tank  103  with flow-through heating element  205  powered with 410 watts in one embodiment.  FIG. 5  is an exemplary graph of the recovery time of water tank  103  with flow-through heating element  205  powered with 410 watts in this same exemplary embodiment. 
     Example methods may be better appreciated with reference to flow diagrams. While for purposes of simplicity, explanation of the illustrated methodologies are shown and described as a series of blocks. It is to be appreciated that the methodologies are not limited by the order of the blocks, as some blocks can occur in different orders and/or concurrently with other blocks from that shown and described. Moreover, less than all the illustrated blocks may be required to implement an example methodology. Blocks may be combined or separated into multiple components. Furthermore, additional and/or alternative methodologies can employ additional, not illustrated blocks. 
       FIG. 6  illustrates a method  600  of heating water in a water tank. The method  600  begins by receiving water at an input line of a water tank at  602 . In some configurations, a recirculation line may be used to flow water into the heating element as illustrated in  FIGS. 1B, 2 and 3  and as discussed above. This recirculated water is then received at a first opening of a flow-through heating element disposed inside the water tank at  604  and heated inside the flow-through element heating element at  606 . In one example, the heating element is at least partially located near a bottom portion of the water tank. The heating element may be a flow-through type heating element where water is heated while flowing from an input opening to an output opening of an elongated channel of the heating element. The heated water is the re-injected the heated water into the water tank at  608  and dispensed from the water tank via an output line at  610 . 
     Other embodiments of method  600  may heat water above a temperature to kill bacteria such as  Legionella  and prevent unwanted biofilms. As discussed above, in other embodiments, method  600  may cool the heated water when it is removed from the tank with a line of cooler water so that it is safe for use. In another embodiment, method  600  may deflect water within the water tank with a deflection plate with openings/slit openings or deflect water in another way to promote thermal mixing of the water. 
       FIGS. 7-10  illustrate an alternate embodiment of a hot water tank with a thermostatic mixing valve (“TMV”). The TMV is adjustable and designed to automatically control the outlet water temperature, subject to user adjustment, to prevent scalding. In addition, the TMV may be arranged on the hot water tank in a manner that makes it easily accessible so as to facilitate replacement and/or maintenance when in use, for example, in confined spaces. 
       FIGS. 7A-7B  illustrate a hot water system  700  (sometimes referred to as the system  700 ) according to one or more embodiments. As illustrated, the hot water system  700  includes a thermostatic mixing valve  701  and a water heater  710 . In the illustrated embodiment, the TMV  701  is integral with the water heater  710 ; however, it will be appreciated that the TMV  701  may be arranged with alternate water heaters without departing from the present disclosure. In one or more embodiments, the TMV  701  is made from wetted materials, including materials suitable for potable drinking water systems, such as stainless steel. 
     In the illustrated embodiment, the water heater  710  includes a tank  714  at a lower end thereof and a cap  711  at an upper end of the water heater  710 . Here, the cap  711  defines a mixing valve chamber  712  and the tank  714  defines a hot water chamber  713  having a diameter D that is filled with fluid (i.e., hot water). In this embodiment, the mixing valve chamber  712  is separated from the hot water chamber  713  by a barrier or wall  715  that inhibits the free flow of fluid between there-between. In some embodiments, the barrier  715  comprises an insulator material, as known in the art. It will be appreciated that, with this arrangement, the cap  711  may be provided as a detachable unit that may be removed from the remainder of the hot water tank  710  (and without exposing the contents of the hot water chamber  711  to the ambient environment), thereby making the hot water system  700  a modular system. In the illustrated embodiment, the cap  711  has a threaded base  717  that may be removably attached to a threaded adapter  719  that is provided at the upper end of the tank  714  of the water heater  710 . It will be appreciated that, in other embodiments, the threaded base  717  and threaded adapter  719  may be differently arranged with on the hot water tank  710  and/or a different connection or fastening means may be utilized to connect the cap  711  to the tank  714  without departing from the present disclosure. Moreover, in some embodiments, the system  700  includes a relief valve R as illustrated in  FIG. 7A . 
     In the illustrated embodiment, the TMV  701  is enclosed within mixing valve chamber  712  of the cap  711 , which is situated on top of the tank  714 . In addition, the TMV  701  is secured within the mixing valve chamber  712 , for example, via a threaded stud extending out of the top end of the cap that is opposite the threaded base  717 ; however, the TMV  701  may be differently secured therein as appreciated by those skilled in the art. In such embodiments, the cap  711  is a housing type structure in which the TMV  701  is enclosed. Accordingly, the cap  711  includes a sidewall  718  that surround the periphery of the TMZ  701  and a lid  720 . Here, the sidewalls  718  are cylindrical and are essentially an extension of tank  714 ; however, other arrangements of the sidewalls  718  and lid  720  may be provided without departing from the present disclosure. In some embodiments, the lid  720  is removable to facilitate maintenance of water heater  710  and/or installation or replacement of TMV  701 . In addition, the cap  711 , including its sidewalls  718  and lid  720 , may be made of various materials, for example, stainless steel 360 housing; however, other materials may be utilized, including those that are suitable for potable drinking water systems. 
     In some embodiments, fluid is introduced into the thermostatic mixing valve  701  via two (2) passage ways, a cold fluid inlet  702  and a warm fluid inlet  704 , whereas fluid of mixed temperature exits the TMV  701  via a fluid outlet  709  that may be fitted with an outlet line  709 ′ that is, for example, adapted to interconnect the system  100  to a sink, shower, or other on demand source of water. The cold-water inlet  702  of TMV  701  may be connected to a common cold water conduit  716  of water heater  710  as depicted, whereas the warm water inlet  704  of TMV  701  may extend into tank  714 , for example, via warm water conduit  706  having a warm water inlet opening  708 . In some embodiments, the fluid outlet  709  extends exterior the cap  711 , whereas in other embodiments, the fluid outlet  709  is terminates within the valve chamber  712  and is fitted with an extension such as  709 ′ that extends exterior the cap  711 . 
       FIG. 7  depicts an embodiment the cold-water conduit  716  according to one or more embodiments. Here, the cold-water conduit  716  extends from the cold-water inlet  702  of the TMV  701  and runs through the interior hot water chamber  713  of the tank  714 . In this embodiment, the cold-water conduit  716  terminates at an opening  723  that is exterior of the hot water chamber  713  and is the point at which cold water is introduced into the hot water system  700 . In addition, the cold-water conduit  716  may include an opening  724  through which at least some of the cold water is introduced into the hot water chamber  713 ; however, the common cold water conduit  716  may be differently oriented with respect to TMV cold-water inlet  702  and opening  724 . 
     As mentioned,  FIG. 7  also depicts the warm water inlet  704  of TMV  701  connected to the conduit  706  that extends downward into the top of tank  714  (i.e., into the hot water chamber  713  thereof) so that the opening  708  of the conduit  706  withdraws water near the top of the water column defined by the hot water chamber  713 , as the temperature of water column near the top of the water column tends to be warmer than the temperature of water column near the water column. In these embodiments, the unheated water that is introduced into the hot water chamber via the opening  724  is circulated through a heating element  721  that provides the heating function of the system  700 . Here, the heating element has an opening  722  near the bottom of the hot water chamber  713  through which cooler water enters the heating element  721 , as well as a hot water outlet  722 ′ through which the warmer water is discharged from the heating element  721 . In addition, the opening  708  of the warm water conduit  706  of the TMV  701  may located a distance L from the hot water outlet  722 ′ of the heating element  721 , and the distance L may be varied depending on the requirements of the particular end use application. In the illustrated embodiment, the distance L is a vertical distance equal to about two (2) to three (3) times the diameter D of tank  714 ; however, in other embodiments, the distance L may be other lengths, for example, at least two (2) times the diameter D of tank  714 . It will be appreciated, however, that the heating element  721 , including its inlet and outlet openings  722 , 722 ′, may be differently arranged without departing from the present disclosure. 
     Locating the thermostatic mixing valve  701  at the top of water heater  710 , for example, within the cap  711  that is disposed on top of the tank  714  such that the opening  708  is vertically spaced from the hot water outlet  722 ′ a vertical distance L, may provide many benefits. Without being bound by theory, the temperature of the water column defined by the hot water chamber  713  varies within the depth of the tank  714  and, therefore, the coolest water will be located near the bottom of the water column, for example, proximate to the opening  724  where cold water is introduced into the hot water chamber  713 ; and the warmest water in the water column will be located near the top of the water column, for example, proximate to the hot water outlet  722 ′ of the heating element  721 . In operation, the cooler water near the bottom of the tank proximate the opening  724  will be mixed with warmer (or hot) water at the top of the water column, and the temperature differential existing in the water column in turn enhances the dynamic thermal mixing even when water is not being drawn into the TMV  701  from the hot water chamber  713 . 
     As mentioned above, the common cold water conduit  716  introduces cooler water into the hot water chamber  713  of the tank  714  via the opening  724  proximate the bottom of the water column and may also introduce cooler water directly into TMV  701  via the cold water inlet  702 , and this arrangement of the common cold water conduit  716  may also provide benefits to the system  700 . For example, this arrangement may minimize the pressure differential to which the TMV  701  is exposed when mixing the warm and cool water. Large pressure differences between the opening  724  and the TMV warm water inlet  704  may cause temperature spikes at the outlet  709  of the system  700 . Without being bound by theory, positioning the thermostatic mixing valve  701  and the mixed temperature water outlet  709  at the top of the water heater  710  may preheat the TMV  701  (i.e., keeps the various components of the TMV  701  preheated) to a sufficient level/temperature, such that most of the heat energy from the water column is transferred to the appropriate components of the TMV  701  (i.e., its thermostatic actuator) that respond to changes in temperature. These components of the TMV  701 , including the thermostatic actuator, are more fully detailed below. 
     TMV  701  operates to ensure steady temperature of water flow exiting TMV outlet  806 .  FIGS. 8A, 8B, 8C, and 8D  illustrate the thermostatic mixing valve  701 , according to one or more embodiments. It will be appreciated that, while some of the components of the TMV  701  were previously identified with respect to  FIGS. 7A-7B , some of those same components (and previously unidentified components) are again identified below with respect to  FIGS. 8A-8D . Thus, as previously mentioned, the TMV  701  comprises a housing  801  having a cold-water inlet  802 , a warm water inlet  804 , and a mixed temperature outlet  806 . In addition, the housing  801  defines a mixing chamber M.  FIGS. 8A and 8D  depict water outlet  806  of TMV  701  having an extension  807  installed thereon to allow water outlet  806  to extend beyond and out of a structure (e.g., the cap  702  defining the mixing valve chamber  712 ). Moreover,  FIG. 8D  depicts cold-water inlet  802  and warm water inlet  804  of the TMV  701  being fitted with the common cool water conduit  716  and the warm water conduit  706 , respectively, whereas such inlet fittings/extensions are not depicted in either  FIG. 8A or 8C . As will be appreciated, the TMV  701  operates to ensure steady temperature of water flow exiting TMV outlet  806 . 
     In this example embodiment, the thermostatic mixing valve  701  further comprises a temperature adjustment screw  810 , an actuator spring  820 , (a thermal actuator  830 , and an active mixing nozzle  840 . The temperature adjustment screw  810  may be utilized to set a cold and hot water control gap C 1 ,C 2  defined by the orientation of the thermal actuator  830  within the mixing chamber M of the housing  801 , thereby setting the desired temperature or ratio of warm and cold that is mixed in the flow exiting water outlet  806 . Here, the adjustment screw  810  may be rotated clockwise or counterclockwise, which in turn displaces the active mixing nozzle  840  within the mixing chamber M, and the displacement or orientation of the active mixing nozzle  840  therein affects the amount of flow entering the cold water and warm water inlets  802 ,  804 . For example, rotating the adjustment screw  810  counterclockwise a predetermined amount (e.g., all the way until it no longer rotates) would displace the active mixing nozzle  840  to a location/orientation where the cold water inlet  802  is fully or almost fully blocked so that mostly warm water enters the TMV  701  via the warm water inlet  804  and only a small amount of cold water (at most) enters the cold water inlet  802 , such that the water flow exiting outlet  806  comprises a steady water flow of the desired temperature or desired ratio of warm water. In some embodiments, cold water is always being mixed with the hot water within the mixing chamber M to lower the TMV outlet  806  fluid temperature by at least some amount or degree. In the foregoing example, rotating the adjustment screw  810  clockwise a predetermined amount (e.g., all the way until it no longer rotates) may displace the active mixing nozzle  840  to a location where the warm water inlet  804  is fully (or almost fully) blocked so that only (or mostly) cold water enters the TMV  701  via the cold water inlet  802 , and the water flow exiting outlet  806  comprises a steady water flow of the desired temperature or desired ration of cold water. Furthermore, the adjustment screw  810  may be adjusted or screwed to any number of rotational orientations between the two extremes (i.e., rotated fully clockwise or counter-clockwise), which in turn displaces the active mixing nozzle  840  to any number of locations between the cold and warm water inlets  802 , 804  so that both warm and cold water are entering the mixing chamber M and the water flow exiting outlet  806  comprises some desired temperature or ratio of warm and cold water. Thus, a user may adjust adjustment screw  810  to fine tune the ratio of warm to cold water entering the mixing chamber M and exiting the outlet  806  of the thermal mixing valve  701 . 
     In the illustrated embodiment, the adjustment screw  810  operates as a positioning member and may be any type of screw known in the art. In one embodiment, the adjustment screw  810  comprises a 316 stainless steel set screw; however, the adjustment screw  810  may be comprised of other materials suitable for potable drinking water systems. In addition, other suitable members in lieu of the screw  810  may be utilized to displace and hold the active mixing nozzle  840  to and at the desired location within the mixing chamber M. For example, the positioning member may instead be a spring-loaded button that is pressed or depressed to displace the active mixing nozzle  840  to the desired orientation. It will be appreciated, however, that other types of positioning members may be utilized in lieu of the adjustment screw  810  as known in the art. Moreover, in other embodiments the adjustment screw  810  is spring loaded to provide a biasing force against the nozzle  840  opposite that applied by the actuator spring  820 . 
     Also in the illustrated embodiment, the actuator spring  820  is a biasing element that biases the thermal actuator  830  so that it returns to equilibrium position in response to either engagement of the adjustment screw  810  and/or a temperature change. As illustrated, the actuator spring  820  is arranged within the housing  801  proximate to the outlet  806  and receives one end (i.e., the thermal expansion portion) of the thermal actuator  830  as hereinafter detailed. The actuator spring  820  may comprise any number of materials, including those that are suitable with potable water drinking systems. In one example, actuator spring  820  comprises a 17-7 pH stainless steel return spring. In other embodiments, a compliant biasing element is utilized in lieu of the actuator spring  820  and operates as described with reference to the actuator spring  820 . It will be appreciated, however, that any number of biasing elements alternatives may be utilized as known in the art. 
     The thermal actuator  830  is a thermo-mechanical device capable of converting a temperature change into motion, and designed to operate within a pre-defined range of temperatures. Actuation of the adjustment screw  810  places the thermal actuator  830  (and the nozzle  840  arranged thereon) at a pre-calibrated position (i.e., a desired temperature). The nozzle  840  has a central bore that receives a guide portion of the thermal actuator  830  and is a shuttle member that travels within the mixing chamber M with the thermal actuator  830 . In addition, the nozzle  840  abuts the flange F of the thermal actuator  840  and is arranged at a location proximate to the adjustment screw  810  such that movement of the adjustment screw  830  displaces the nozzle  840  between the cold and hot water inlets  802 , 804 , thereby setting the cold and hot water control gaps C 1 ,C 2 . As will be appreciated, the cold and hot water control gaps C 1 ,C 2  may inhibit temperature spikes. The thermal actuator  830  includes an expansion material that expands or retracts in response to a temperature change and, in the illustrated embodiment, is arranged on the portion of the thermal actuator  830  that is received within the spring  820  and proximate to the flange F. Accordingly, as the expansion material expands/retracts, the flange F of the thermal actuator  830  that abuts the nozzle  840  may displace the nozzle  840  to further control or regulate the flow of hot and cold water through cold and hot water inlets  802 , 804  such that a mixed water temperature flowing through the mixing chamber M remains steady, at the user&#39;s pre-set value. For example, the stability of the pre-set temperature is controlled as the expansion material reacts to a temperature increase by expanding and displacing the nozzle  840 , which in turn simultaneously reduces the hot water control gap C 2  and increases the cold water control gap C 1  such that the outlet  806  temperature returns to the user&#39;s pre-set value. 
     In the illustrated embodiment, the thermal actuator  830  is disposed within the housing  801  of TMV  701  and arranged between the adjustment screw  810  and the actuator spring  820 . In the illustrated embodiments, the thermal actuator  830  utilizes a wax as its expansion material; however, other materials may be utilized such as, for example, a shape memory alloy, a MEMS thermal actuator, or others as known in the art.  FIG. 9  illustrates the thermal actuator  830  configured as a wax actuator, according to one or more embodiments. In this example, the thermal actuator  830  comprises (i) a hollow actuator guide  902  that is cupped or flanged at one end  902 ′ to form the flange F; (ii) a piston  904  extending there-through that includes an end  904   a  that exits guide  902  at an end opposite of the flange F and a plug end  904   b  that extends into the flange F; (iii) a diaphragm  906  attached to the plug end  904   b  of the piston  904  within the flange F of the guide  902 ; and (iv) an expansion compartment  908  attached to the end of the flange F at the diaphragm  906  and containing an expansion material  910  therein. 
     In the illustrated embodiment, the expansion compartment  908  is arranged or nested within the adjustment spring  820  and, when the expansion material  910  within the expansion compartment  908  is exposed to temperature changes, it expands or retracts. The expansion/retraction of the expansion material  910  in turn displaces the diaphragm  906  and the piston  904  attached thereto a stroke distance, which in turn displaces the thermal actuator  830  and the active mixing nozzle  840  towards the spring  820  (i.e., in response to heat increase) to decrease control gap C 2  and increase control gap C 1 , or towards the screw  810  (i.e., in response to heat decrease/cooling) to decrease control gap C 1  and increase control gap C 2 . For example, the thermal material may expand in response to a heat increase thereby displacing the thermal actuator  830  and the active mixing nozzle  840  so as shrink/close the warm water inlet  804  (i.e., by shrinking the hot water control gap C 2 ) and increase the cold water inlet  802  (i.e., and its control gap C 1 ), thereby decreasing the amount of warm water entering the mixing chamber M. Moreover, the end  904   a  of the piston  904  extends beyond the guide  902  to interact with the adjustment screw  810 , so that a user may adjust the maximum displacement of active mixing nozzle  840  within the mixing chamber M, thereby setting the minimums gap values for the cold and hot control gaps C 1 ,C 2 . In this embodiment, the external components (i.e., the non-actuating components) of the thermal actuator  830  are comprised of an alloy, for example, a copper allow C90300; however, other materials may be utilized, including those that are suitable for potable drinking water systems. 
     In some embodiments, hot water is always being drawn into the mixing chamber M from the top of the water column where the water temperature is the highest, and then mixed with pre-heated cooler water within the active mixing nozzle  840  of the TMV  701 .  FIGS. 10A-10B  depicts the active mixing nozzle  840 , according to one or more embodiments. In the illustrated embodiment, the active mixing nozzle  840  has four (4) slots (i.e.,  1002   a ,  1002   b ,  1002   c , and  1002   d ) formed or machined into an edge  1004  of a cold-water side  1006  of the nozzle  840 . The nozzle  840  further includes a warm water side  1008  that is opposite the cold water side  1006 , and a central bore B that extends through the nozzle from the cold water side  1006  (or a face thereof) to the warm water side  1008  (or a face thereof). As best illustrated in  FIG. 10B , the central bore B is smaller at the warm water side  1008  than at the cold water side  1006 , and is sized to receive the expansion compartment  908  (of the thermal actuator  930 ) when inserted therein from the warm water side  1008  of the nozzle  840 . Stated differently, the central bore B that is proximate to the warm water side  1008  has a diameter that is smaller than the diameter of the larger bore portion B′ that is proximate to the cold water side  1006 . Here, the central bore B receives the expansion compartment  908  of the actuator  830  such that a bottom side of the flange F abuts the warm water side  1008  of the nozzle  840 , and the central bore B opens with a larger diameter at the cold water side  1006 . The nozzle  840  further includes a plurality of channels arranged around the central bore B, such as channels  1010   a , 1010   b , 1010   c , 1010   d , which are formed through the face of the warm water side  1008  and extend into the larger portion B′ of the central bore B proximate the cold water side  1006 . When the nozzle  840  is arranged within the housing, the channels  1010   a , 1010   b , 1010   c , 1010   d  coincide with the mixing chamber M and form the passageway through which cold water flows from the cold-water inlet  802  to the mixed temperature water outlet  806 . 
     In one embodiment, the slots  1002   a - 1002   d  are spaced 90 degrees apart; however, other special arrangement may be utilized other than 90 degrees along the circumference/periphery of the nozzle  840  and, moreover, more or less slots may be utilized at other orientations along the circumference/periphery. Without being bound by theory, however, the depicted configuration may reduce the thermal spikes that are known to occur. The slots  1002   a - 1002   d  also insure that there is a minimum amount of cold water flow to reduce the maximum hot water temperature flowing out of the outlet  806  of the thermostatic mixing valve  701  to a safe level. In the illustrated embodiments, the active mixing nozzle  840  is mostly directing the cold water flow to be mixed with the hot, and much of the mixing of warm and cold water streams occurs near the end of the thermal actuator that contains the thermal expansion material (i.e., much of the mixing occurs at an end of the housing  801  where the spring  820  is arranged). In one embodiment, the active mixing nozzle  840  is made from Polytetrafluoroethylene (PTFE); however, other materials may be utilized, including those that are suitable for potable drinking water systems. In addition, the nozzle  840  may include annular recesses along its outer periphery that receive one or more seals or gaskets such as, for example O-rings. 
     As mentioned above, positioning the thermostatic mixing valve  701  and its mixed temperature water outlet at the top of the tank (e.g., tank  714 ) keeps the TMV  701  components pre-heated to a point where most of the heat energy from the water column is transferred to the thermostatic actuator  830  (and the expansion material  910  therein) that responds to changes in temperature. This enhances the system&#39;s overall efficiency. For example, in the embodiment where thermal actuator  830  is a wax actuator, thermal expansion of the wax inside of the thermal actuator  830  moves the active mixing nozzle  840  to a position where the desired pre-set ratio of hot and cold-water mix is achieved at the mixed water temperature outlet  806  of the TMV  701 . 
     Therefore, the disclosed systems and methods are well adapted to attain the ends and advantages mentioned as well as those that are inherent therein. The particular embodiments disclosed above are illustrative only, as the teachings of the present disclosure may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. It is therefore evident that the particular illustrative embodiments disclosed above may be altered, combined, or modified and all such variations are considered within the scope of the present disclosure. The systems and methods illustratively disclosed herein may suitably be practiced in the absence of any element that is not specifically disclosed herein and/or any optional element disclosed herein. While compositions and methods are described in terms of “comprising,” “containing,” or “including” various components or steps, the compositions and methods can also “consist essentially of” or “consist of” the various components and steps. All numbers and ranges disclosed above may vary by some amount. Whenever a numerical range with a lower limit and an upper limit is disclosed, any number and any included range falling within the range is specifically disclosed. In particular, every range of values (of the form, “from about a to about b,” or, equivalently, “from approximately a to b,” or, equivalently, “from approximately a-b”) disclosed herein is to be understood to set forth every number and range encompassed within the broader range of values. Also, the terms in the claims have their plain, ordinary meaning unless otherwise explicitly and clearly defined by the patentee. Moreover, the indefinite articles “a” or “an,” as used in the claims, are defined herein to mean one or more than one of the elements that it introduces. If there is any conflict in the usages of a word or term in this specification and one or more patent or other documents that may be incorporated herein by reference, the definitions that are consistent with this specification should be adopted. 
     The use of directional terms such as above, below, upper, lower, upward, downward, left, right, and the like are used in relation to the illustrative embodiments as they are depicted in the figures, the upward or upper direction being toward the top of the corresponding figure and the downward or lower direction being toward the bottom of the corresponding figure. 
     As used herein, the phrase “at least one of” preceding a series of items, with the terms “and” or “or” to separate any of the items, modifies the list as a whole, rather than each member of the list (i.e., each item). The phrase “at least one of” allows a meaning that includes at least one of any one of the items, and/or at least one of any combination of the items, and/or at least one of each of the items. By way of example, the phrases “at least one of A, B, and C” or “at least one of A, B, or C” each refer to only A, only B, or only C; any combination of A, B, and C; and/or at least one of each of A, B, and C.