Patent Publication Number: US-2022214049-A1

Title: Combination space and hot water heater

Description:
RELATED APPLICATION 
     The application is related to and claims the benefit of U.S. Provisional Application No. 63/134,426, filed on Jan. 6, 2021 the entire contents of which are incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention pertains to the field of providing space heating and hot water in a facility, and in particular a compact, combination space heater and hot water heater that provides ease of control and maintenance. 
     BACKGROUND 
     Modern buildings in colder locations require a space heater, such as a furnace, and a hot water heater to supply the needs of residents and to keep the building at a temperature to provide comfort to residents and to prevent damage to items that cannot tolerate very low or freezing temperatures. 
     A common type of furnace is a forced air furnace that uses hot air to carry heat through the building through ducts. Heat is created in a heat exchanger which may use hot water flowing through coils to heat air blown over the coils. 
     A common type of hot water heater is a tankless heater that heats water on demand, as it is required, without requiring a holding tank. 
     In many cases, a furnace and a hot water heater are separate appliances. They are often installed in close proximity in a building in a basement, utility room, or utility closet. However, in some cases the furnace and hot water heater are combined in a single appliance. In this case it is possible to have a tankless hot water heater combined with a force air furnace where hot water from the water heater is supplied to both the hot water supply of the building and to the heat exchanger of the furnace to provide hot air for heating the building. 
     Present day combination appliances suffer from a number of drawbacks. In some cases, access to parts that require frequent maintenance, such as a furnace air circulation blower, requires access to the side or rear of the appliance. This limits installations to locations with sufficient space to allow access from the sides or rear. In other cases, the location and routing of water input and output piping connections lead to water pipes blocking or restricting access to user replaceable parts such as furnace air filters. The use case where both hot water and hot air is required at the same time is often handled in an inadequate manner where a demand for hot air causes disruption to the delivery of hot water at a set temperature. Inadequate isolation between the hot water of the water heater and the furnace may lead to further inefficiencies and heat loss in the system. Finally, the user interface of heating appliances is often difficult to setup, monitor and adjust. 
     Therefore, there is a need for a method and apparatus for an improved combination furnace and hot water heater that obviates or mitigates one or more limitations of the prior art. 
     This background information is provided to reveal information believed by the applicant to be of possible relevance to the present invention. No admission is necessarily intended, nor should be construed, that any of the preceding information constitutes prior art against the present invention. 
     SUMMARY 
     An object of embodiments of the present invention is to provide an apparatus for providing heating and hot water to a facility that is compact and easy to maintain when installed in a confined space that only provides adequate access to a front face of the apparatus. When installed in a confined space internal components and assemblies of the water heater and the air heater may be accessed and replaced through a front face of the apparatus. When there is no demand for hot air, hot water from the water heater assembly portion of the apparatus may be thermally isolated from the hot air assembly portion. A common controller may take into account simultaneous demand for hot water and heat to ensure that a flow of hot water is not interrupted. 
     In accordance with embodiments of the present invention, there is provided a combination space and water heating apparatus including a frame enclosing a water heating assembly and an air heating assembly. The water heating assembly is positioned in a top front portion of the frame and supplies hot water in response to a hot water demand. The water heating assembly includes inlet and outlet water connections through a top portion of the water heating assembly. The air heating assembly is positioned in a rear and bottom portion of the frame and supplies heated air in response to a space heating demand. Maintenance access to the air heating assembly solely through a front section of the bottom portion of the frame. 
     Embodiments further include a central controller assembly coupled to the water heating assembly and to the air heating assembly. The controller assembly produces or manages the hot water demand and the space heating demand, and the space heating demand can be set to have a delay when hot water demand is active. 
     Embodiments further include a connection for an inlet for recirculated water through the top portion of the water heating assembly. The controller assembly manages the recirculated water function within the water heating assembly. 
     Embodiments further include an air circulation blower of the air heating assembly. The air circulation blower is mounted direct to the frame and could also be mounted on an extendable mount of the frame and accessible through a bottom portion of the front section of the frame. 
     In further embodiment, the water output from the water heating assembly is coupled to the air heating assembly through a U-trap. The U-trap prevents natural heat flow from the water heating assembly into the air heating assembly when the space heating demand is inactive. 
     Embodiments further include water piping connections positioned on a top surface of the frame. The water piping connections allow for input and output of water into the water heating assembly. 
     Embodiments further include a water heater component of the water heating assembly, and a water to air heat exchange component of the air heating assembly. The water heater component is mounted on a first extendable mount of the frame and accessible through the front section of the frame. The air heat exchange component is mounted on a second extendable mount of the frame and accessible through the front section of the frame. 
     In further embodiment, the water heating assembly is a tankless water heater, boiler, or other heat generation component. 
     In accordance with embodiments of the present invention, there is provided a method for controlling the heating of air and water in a combination apparatus. The method includes detecting a space heating demand of an air heating assembly of the apparatus. Enabling the delay of the air heating assembly when the air heating assembly was enabled when detecting a hot water demand of a water heating assembly of the apparatus. Enabling the air heating assembly after a delay when the air heating assembly was disabled when detecting the hot water demand. 
     Embodiments have been described above in conjunctions with aspects of the present invention upon which they can be implemented. Those skilled in the art will appreciate that embodiments may be implemented in conjunction with the aspect with which they are described, but may also be implemented with other embodiments of that aspect. When embodiments are mutually exclusive, or are otherwise incompatible with each other, it will be apparent to those skilled in the art. Some embodiments may be described in relation to one aspect, but may also be applicable to other aspects, as will be apparent to those of skill in the art. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       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: 
         FIG. 1  provides an isometric view of a combination water heater and air heater, according to an embodiment. 
         FIG. 2  provides a side view of a combination water heater and air heater illustrating the water heater portion and the air heater portion, according to an embodiment. 
         FIG. 3  provides an opposing side view of a combination water heater and air heater illustrating a heat trap between the water heater portion and the air heater portion, according to an embodiment. 
         FIG. 4  provides a side view of a combination water heater and air heater illustrating front access for maintenance purposes or to replace or service components, according to an embodiment. 
         FIG. 5  illustrates a flowchart of a method to control the hot water heating function of the combination water heater and air heater, according to an embodiment. 
         FIG. 6  illustrates a flowchart of a method to control the hot air heating function of the combination water heater and air heater, according to an embodiment. 
         FIG. 7  is a block diagram of an electronic device  700  that may be incorporated into a controller assembly used to configure and control the operation of a combined air heater and water heater according to an embodiment. 
     
    
    
     It will be noted that throughout the appended drawings, like features are identified by like reference numerals. 
     DETAILED DESCRIPTION 
     Embodiments of the present invention relate to an apparatus for providing air (space) heating and hot water to a facility that is compact and easy to maintain when installed in a confined space that only provides adequate access to a front face of the apparatus. When installed in a confined space internal components and assemblies of the water heater and the air heater may be accessed and replaced through a front face of the apparatus. When there is no demand for hot air, hot water from the water heater assembly portion of the apparatus may be thermally isolated from the hot air assembly portion. A common controller, which may be centralized, may take into account simultaneous demand for hot water and air heat to ensure that the temperature and flow of hot water is not interrupted. 
       FIG. 1  provides an isometric view of a combination water heater and air heater, according to an embodiment. The apparatus  100  provides the dual functions of air heating (space heating or heating by a furnace) and water heating from one product, which occupies a small footprint, similar to the footprint of a traditional furnace, while allowing access to components from a front section of the apparatus  100 . Embodiments can be installed into a space or room with walls enclosing it on all three sides; back, left, and right, resulting in reduced space required for installation in a home, building, or facility. 
     A cabinet or enclosure, hereafter referred to as a “frame”, is a box-like enclosure to support the apparatus, and its assemblies within, and allowing it to connect to external piping, for water, fuel, electric wiring, venting, and ductwork to distribute warm air and to provide a cold air return. The frame is typically made of a suitably rigid metal material but may be made of any material, such as plastic, that has suitable properties to support and enclose the assemblies and components housed, therein. A water heating assembly  102  is positioned in a top front portion of the frame. The frame and water heating assembly  102  are designed so that when the water heating assembly  102  is installed within the frame it does so in a way that does not block access to components inside an air heating assembly  104  also installed within the frame. Embodiments allow for servicing of components through a front portion of the frame that does not require access to the sides or back of the apparatus. Access to the water heating assembly  102  may be through a portion or panel in an upper portion of the front side of the frame. 
     In embodiments, water heating assembly  102  is an on-demand or “tankless” water heater. In other embodiments assembly  102  may be a boiler or other water heating device. 
     Air heating assembly  104  is located in the rear and bottom portion of the frame to allow access through a portion or panel in a lower portion of the front side of the frame. Air heating assembly  104  receives cool air through duct work connected to cool air return ducting of the facility where the apparatus is installed. Cool air is blown over a heat exchange that may include piping that receives hot water from water heating assembly  102 , thereby heating the air which is then distributed through the facility through ductwork  118 . 
     In other embodiments, water heating assembly  102  is positioned in a bottom front portion of the frame. The frame and water heating assembly  102  are designed so that when the water heating assembly  102  is installed within the frame it does so in a way that does not block access to components inside an air heating assembly  104  also installed within the frame. Access to the water heating assembly  102  may be through a portion or panel in a lower portion of the front side of the frame. In this embodiment, air heating assembly  104  may be located in the rear and top portion of the frame to allow access through a portion or panel in an upper portion of the front side of the frame. In this case, any or all of water connections  108 ,  110 , and optionally,  112 , as well as inlet/outlet connections  114  and  116  may be moved to a lower portion of the frame to provide connections without blocking access to water heating assembly  102  or air heating assembly as described herein. In embodiments, inlet and outlet connections may be located on either side, bottom, or back of apparatus  100 , with the restriction that they be of a size and placed so as not to prevent access to serviceable or maintenance items or assemblies. 
     In embodiment, air heating assembly uses a water to air heat exchanger in which hot water from water heating assembly  102  is used to generate hot air blown over the exchanger by a fan. 
     Water piping connections may be located in a top portion of the frame. Water piping connections may include a cold water inlet  108 , a hot water outlet  110 , and an optional recirculated water inlet  112 . The placement of water piping connections at the top of the frame allows for easy access and installation of external water piping and also prevents water pipes from getting in the way of serviceable components, such as furnace filters that are typically placed where the cold air return enters the frame at a side or rear side of the frame. 
     A centralized controller  106  may be used to configure, control, and operate both water heating assembly  102  and air heating assembly  104  of the apparatus. Controller  106  incorporates operating software logic that recognizes when there is a hot water demand or a hot air demand present. In particular, when a space heating demand occurs while hot water is being produced, the software logic will delay the space heating assembly from turning on for a fixed or adjustable time period, at which point it then allows both the air heating assembly  104  and water heating assembly  102  to function at the same time. Controller  106  may be wholly incorporated in the apparatus and include a display and user input controls such as push buttons or dials. Controller  106  may also be implemented is a distributed manner with a local portion interfacing to control the water heating assembly  102  and the air heating assembly  104 , and a remote portion that may be a remote control panel, mobile device, tablet, or computer. The remote portion of controller  106  may be connected through a wired connection or a wireless connection such as Bluetooth, Zigbee, WiFi, or cellular data. 
     In embodiments that include recirculated water inlet  112 , controller  106  may incorporates software to enable the circulation of water thru a hot water recirculation line in a facility. The components and control functionality are built-in to the apparatus and no external components are necessary other than external connections. The recirculation line receives water back from the water outlet or supply line which has been distributed through the facility. Upon returning back into the water heating assembly the controller will re-heat and manage the water temperature according to preset functionality. The cooled water is still at a higher temperature than the cold water supply  108  of the hot heating assembly. Recirculated water is mixed with the hot or cold water to produce hot water output at the configured temperature. 
       FIG. 2  provides a side view of a combination water heater and air heater illustrating the water heater portion and the air heater portion, according to an embodiment. Water heating assembly  102  is in a top front portion of the frame of the apparatus. Air heating assembly  104  is located in a rear and bottom portion of the frame, connecting to air ducts  118  at the top. Water piping connections, including cold water inlet  108  and hot water outlet  110  are located in a top portion of the frame. Air inlets and exhausts  114  and  116  are also located in a top portion of the frame. 
       FIG. 3  provides an opposite side view of a combination water heater and air heater illustrating a heat trap between the water heater portion and the air heater portion, according to an embodiment. Water heating assembly  102  is in a top front portion of the frame of the apparatus. Air heating assembly  104  is located in a rear and bottom portion of the frame, connecting to air ducts  118  at any side, bottom, top, or any combination of these locations. Water piping connections, including a cold water inlet  108  and a hot water outlet  110  are located in a top portion of the frame. Gas inlets and exhausts  114  and  116  are also located in a top portion of the frame. A “U-trap”  302  is incorporated into internal hot water supply line which connects water heating assembly  102  to air heating assembly  104 . U-trap  302  is specially designed to prevent natural heat convection from the water heater into the water-to-air heating coil in the furnace section, in particular when there is demand for hot water and the water heating assembly  102  is enabled and generating hot water, and there is no demand for hot air and air heating assembly  104  is disabled. In embodiments, the input to the U-trap  302  is at least 8 inches higher than the bottom of the bend of the pipe. In embodiments, U-trap  302  may be implemented as a heat trap, thermosiphon block, check-valve, mechanical valve, or other similar technology. 
       FIG. 4  provides a side view of a combination water heater and air heater illustrating front access for maintenance purposes or to replace or service components, according to an embodiment. Access to air heating assembly  104  is available through a front section of the bottom portion of the frame. An air circulation blower  402   a  is used to illustrate how rails  404  may be used to allow the removal of components of air heating assembly  104  for configuration, repair, replacement, or any other maintenance activity. Element  402   a  illustrates the air circulation blower in place when in use. Element  402   b  illustrates how air circulation blower may be extracted for easier access. Blower  402   a  or  402   b  may direct air as shown by arrow  410  and may direct air in either direction as dictated by the setup of apparatus  100  to ensure correct operation. Similarly, components  406   a  of water heating assembly  102  is used to illustrate how rails  408  may be used to allow the removal of components of water heating assembly  102  for configuration, repair, replacement, or any other maintenance activity. Element  406   a  illustrates the components in place when in use. Element  406   b  illustrates shows how the component may be extracted for easier access. It is understood that both water heating assembly  102  and air heating assembly  104  include multiple components or groups of components that may be accessible through a front section of the frame for maintenance access. It is also understood that other methods of extraction, other than rails  404  and  408  may be used in embodiment without changing the teachings and disclosure herein. 
     In an embodiment, frame  102  may be constructed on a base (not shown) that allows for all of or a portion of apparatus  100  to be raised off the ground. Blower  402   b  and other components may then be removed through the bottom of apparatus  100  to be accessed and replaced from the front of apparatus  100  with apparatus  100  in the raised position. 
       FIG. 5  illustrates a flowchart of a method  500  to control the hot water heating function of the combination water heater and air heater, according to an embodiment. Method  500  may be implemented in controller  106  which may interface with the hot water assembly  102  by receiving inputs from sensor and sending commands using analog or digital electrical signals. Both the water heating assembly  102  and the air heating assembly  104  may have a “demand” and a “function.” A demand represents an input to controller  106 . It may signify that a hot water tap has been turned on and a thermostat has detected that the temperature of the water is below the set point and must be heated. It may signify that a thermostat has detected that the air temperature of the facility is below the set point and that hot water air heating assembly  104  must generate hot water for the heat exchanger of the air heating assembly  104  and that the blower of the air heating assembly  104  must be turned on. Similarly, demands indicate when to turn off either the water heating assembly  102  or the air heating assembly  104 . “Function” represents an output from controller  106  that involves turning on or off the burner of water heater, turning on the blower of the air heating assembly  104 , etc. 
     Initially the system is in stand-by mode  502 . In step  504 , controller  106  monitors the hot water heating demand to determine if it is ON, i.e., there is a demand for hot water. If the hot water heating demand is ON, in step  506  the controller  106  maintains the hot water heating function at ON to instruct the water heating assembly  102  to generate or continue to generate hot water. In step  506 , if the hot water heating function is OFF, the controller  106  instructs the hot water heating function to turn ON and to start generating hot water. The controller then transitions back to step  504  and continues to monitor the hot water heating demand. 
     If the hot water heating demand is not ON, i.e., there is no demand for hot water, in step  508  the controller  106  checks to see if the water heating assembly  102  function is presently ON, i.e., generating hot water. If the water heating assembly  102  function is not presently ON, the controller transitions back to stand-by mode  502 . If the water heating assembly  102  function is presently ON, in step  510  the controller  106  initiates the hot water heating post purge function, and in step  512 , the hot water heating function is set to OFF. After step  512 , stand-by mode  502  is returned to. 
       FIG. 6  illustrates a flowchart of a method  600  to control the hot air heating function of the combination water heater and air heater, according to an embodiment. Initially the system is in stand-by mode  502 . In step  610 , controller  106  monitors the hot air heating demand to determine if it is ON, i.e., there is a demand for hot air for heating. If there is no demand, in step  604  controller  106  checks if the air heating function is currently ON, i.e., hot air is being produced by air heating assembly  104 . If the air heating function is not ON, controller  106  transitions back to stand-by mode  502 . If the air heating function is ON, controller  106  transitions to step  606 . In step  606 , controller  106  sets the air heating function to OFF. Then in step  608 , controller  106  initiates an air heating post purge function and transitions back to stand-by mode  502 . 
     In step  610 , controller  106  monitors the hot air heating demand to determine if it is ON, i.e., there is a demand for hot air for heating. If there is demand, in step  612  controller  106  determines if a hot water heating demand is present. If there is no hot water heating demand presently, i.e., only an air heating demand is present, then in step  614 , controller  106  sets the air heating function to ON to instruct the air heating assembly  104  to product hot air for heating of the facility. The controller  106  then transitions to step  610  to continue to monitor that there is an air heating demand. 
     In step  612 , if there is a hot water heating demand present while there is a simultaneous air heating demand (step  610 ), then in step  616  the controller determines if the air heating function is already ON. If the air heating function is presently ON, then it may remain on in step  614 . In step  614 , if air heating demand is ON, then it will be maintained in the ON state. If air heating demand is OFF, then the air heating demand will be set to ON. If the air heating function is not presently ON, then in step  618 , a timer is started to delay the enabling of the air heating function. This prevents the enabling of the air heating function, that requires hot water, from adversely affecting the water heating function that is already in use supplying hot water. In embodiment, a default value of the timer of step  618  is 900 seconds. In step  620 , the controller checks the value of the timer to see if it the delay time has passed since the timer was set. If the timer has decremented to zero, then controller  106  transitions to step  614  and the air heating function is set to ON. If the timer still has time to run, the controller transitions to step  610  to verify that the air heating demand is still present. 
     It is understood that the method  500  of  FIG. 5  and method  600  of  FIG. 6  may be performed individually or simultaneously with each other. 
       FIG. 7  is a block diagram of an electronic device  700  that may be incorporated into a controller assembly used to configure and control the operation of a combined air heater and water heater according to an embodiment. For example, a computer or mobile device equipped with network function may be configured as electronic device  700 . 
     As shown, the device  700  includes a processor  702 , such as a microcontroller, a central processing unit (CPU) or specialized processors such as a graphics processing unit (GPU) or other such processor unit, memory  704 , non-transitory mass storage  706 , I/O interface  712 , and a network interface  716 , all of which are communicatively coupled via a bus or interconnect. According to certain embodiments, any or all of the depicted elements may be utilized, or only a subset of the elements. Further, the device  700  may contain multiple instances of certain elements, such as multiple processors, memories, or transceivers. Also, elements of the hardware device may be directly coupled to other elements without the bus. Additionally, or alternatively to a processor and memory, other electronics, such as integrated circuits, may be employed for performing the required logical operations. 
     The memory  704  may include any type of non-transitory memory such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous DRAM (SDRAM), read-only memory (ROM), any combination of such, or the like. The mass storage element  706  may include any type of non-transitory storage device, such as a solid state drive, hard disk drive, a magnetic disk drive, an optical disk drive, USB drive, or any computer program product configured to store data and machine executable program code. According to certain embodiments, the memory  704  or mass storage  706  may have recorded thereon statements and instructions executable by the processor  702  for performing any of the aforementioned method operations described above. 
     It will be appreciated that, although specific embodiments of the technology have been described herein for purposes of illustration, various modifications may be made without departing from the scope of the technology. The specification and drawings are, accordingly, to be regarded simply as an illustration of the invention as defined by the appended claims, and are contemplated to cover any and all modifications, variations, combinations or equivalents that fall within the scope of the present invention. In particular, it is within the scope of the technology to include a computer program product or program element, or a program storage or memory device such as a magnetic or optical wire, tape or disc, or the like, for storing signals readable by a machine, for controlling the operation of a computer according to the method of the technology and/or to structure some or all of its components in accordance with the system of the technology. 
     Although the present invention has been described with reference to specific features and embodiments thereof, it is evident that various modifications and combinations can be made thereto without departing from the invention. The specification and drawings are, accordingly, to be regarded simply as an illustration of the invention as defined by the appended claims, and are contemplated to cover any and all modifications, variations, combinations, or equivalents that fall within the scope of the present invention.