Water heater with passive automatic hot water circulation through a home or building

Abstract

A water heater unit is described for providing convective water flow through a water circulatory system. In one embodiment, the water heater unit has an outer housing, a water tank disposed within the housing, and a first cold water inlet coupled to the tank and connectable to a cold water supply line. A hot water outlet is coupled to the tank and connectable to a hot water supply line. A connection chamber adjacent to the tank has a second cold water inlet connectable to the cold water line, and a chamber outlet connected to the first cold water inlet of the tank. The connection chamber has at least one return inlet connectable to the hot water return line at a position to allow a substantially continuous flow of return hot water driven by convection forces without the benefit of a recirculation pump.

1 . A water heater unit connectable to a water flow circuit having a hot water supply line, a hot water return line connected to the hot water supply line, and a cold water supply line, comprising:
 an outer housing;   a water tank disposed within the housing;   a first cold water inlet coupled to the tank and connectable to the cold water supply line;   a hot water outlet coupled to the tank and connectable to the hot water supply line; and   a connection chamber within the housing and adjacent to the tank, the connection chamber having a second cold water inlet connectable to the cold water line, a chamber outlet connected to the first cold water inlet of the tank, and at least one return inlet connectable to the hot water return line at a position to allow a substantially continuous flow of return hot water driven by convection forces without the benefit of a recirculation pump, and a valve connected to the return inlet and being moveable between open and closed positions, the valve in the open position allowing recirculated hot water to flow into the chamber from the return line for return into the tank, and the valve in the closed position blocking water from flowing from the chamber through the return line.   
   
   
       2 . The water heater unit of  claim 1  wherein the chamber outlet has a tubular portion threadably engageable with the first cold water inlet of the water tank. 
   
   
       3 . The water heater unit of  claim 1  wherein the chamber is positioned immediately adjacent to the tank. 
   
   
       4 . The water heater unit of  claim 1  wherein the chamber is connected to a water inlet on the top or side of the tank. 
   
   
       5 . The water heater unit of  claim 1  wherein the housing has at least one access panel that provides access to the return inlet and the cold water inlet of the connection chamber. 
   
   
       6 . The water heater unit of  claim 1  wherein the connection chamber is fully enclosed by the housing, and wherein the housing has a first access portion that receives the cold water line and a second access portion that receives at least one hot water return line. 
   
   
       7 . The water heater unit of  claim 1  wherein the housing includes a body portion surrounding the water tank and a cap portion that connects to a top of the body portion, the connection chamber being disposed in the cap portion. 
   
   
       8 . The water heater unit of  claim 7  wherein the cap portion is moveable between a closed position wherein the connection chamber is enclosed within the cap portion, and an open position wherein the connection chamber is exposed and accessible. 
   
   
       9 . The water heater unit of  claim 1  wherein the housing, the water tank, and the connection chamber are integrally connected to form a transportable unit connectable to the cold water line and the hot water supply line of a water system in a dwelling. 
   
   
       10 . The water heater unit of  claim 1 , further comprising insulation connected to the housing generally adjacent to the connection chamber. 
   
   
       11 . The water heater unit of  claim 1  wherein the connection chamber has a plurality of return inlets, each configured to connect to a separate one of a plurality of water return lines. 
   
   
       12 . A pumpless hot water recirculation kit for installation in a dwelling having a water flow circuit having a hot water supply line and a cold water supply line, wherein the hot water supply line is connected to a water outlet assembly, and at least one hot water return line is connected to the hot water supply line adjacent to the water outlet assembly, comprising:
 a water heater remote from the water outlet assembly, the water heater having a housing, a tank disposed within the housing, a first cold water inlet coupled to the tank and connectable to the cold water supply line, and a hot water outlet coupled to the tank and connectable to the hot water supply line; and   a recirculation device adjacent to the tank, the recirculation device having an interior chamber, a second cold water inlet coupled to the chamber connectable to the cold water supply line, a chamber outlet connected to the first cold water inlet of the tank, and a return inlet connectable to the hot water return line to allow a substantially continuous flow of return hot water driven by convection forces without the benefit of a recirculation pump, wherein the connection chamber is accessible to connect to the cold water line and the hot water return line at or through the housing.   
   
   
       13 . The kit of  claim 12  wherein the recirculation device has a body, a first stub that extends from the body and that defines the chamber outlet, and a second stub spaced apart from the first stub, the second stub extending from the body and defining the return inlet. 
   
   
       14 . The kit of  claim 13  wherein the first stub is threaded and configured to threadably engage the cold water inlet of the tank. 
   
   
       15 . The kit of  claim 13  wherein the second stub includes a coupling that provides a watertight fluid coupling between the second stub and the hot water return line. 
   
   
       16 . The kit of  claim 13  wherein the recirculation device connects directly to the water supply inlet on the top or side of the tank. 
   
   
       17 . The kit of  claim 12  wherein the housing includes a tank portion and a cap connected to the top of the tank portion, the tank portion substantially surrounding the tank, and the cap at least partially containing the recirculation device, the cap having a first aperture configured to be at least adjacent to the cold water supply line, and the cap having a second aperture configured to be at least adjacent to the hot water return line. 
   
   
       18 . The kit of  claim 12  wherein the chamber outlet includes a tubular portion projecting from the body and being threadably engageable with the first cold water inlet. 
   
   
       19 . The kit of  claim 12  wherein the recirculation device has a plurality of return inlets, each return inlet having a valve therein moveable between open and closed positions and configured to allow water to flow through the return inlet in only one direction toward the chamber. 
   
   
       20 . A pumpless water recirculation assembly for convective recirculation of water through a water circuit to a water heater; said water heater having a cold water inlet and a hot water outlet; said water circuit having a hot water supply line, a cold water supply line, and a hot water recirculation line connected to the hot water supply line, comprising:
 a body having an interior chamber;   an outlet portion coupled to the interior chamber and threadably connectable to the cold water inlet of the tank;   a first inlet portion coupled to the chamber and sealably connectable to the cold water line;   a plurality of hot water return inlets coupled to the chamber and sealably connectable to the recirculation line(s) such that at least a segment of the recirculation line is disposed vertically above the water heater, each hot water return inlet having a flow control valve therein configured to allow hot water to flow in one direction from the recirculation line into the chamber and to block water flow in a reverse direction from the chamber through the hot water return inlet; and   a cover member connectable to the tank to define an interior area and configured to contain at least a portion of the body within the interior area, the cover having a first opening in alignment with the first inlet and a second opening in alignment with the hot water return inlet;   wherein the water recirculation assembly is installable in the water circuit to provide a substantially continuous flow of return hot water driven by convection forces in the water circuit without the benefit of a recirculation pump.   
   
   
       21 . The assembly of  claim 20  wherein the outlet portion has external threads that threadably engage the cold water inlet of the water tank. 
   
   
       22 . The assembly of  claim 20  wherein the cover member is a cap that attaches to a top of the water heater. 
   
   
       23 . The assembly of  claim 20  wherein the outlet portion, the first inlet portion, and the hot water inlets are insertable in the water circuit for a retrofit of the water circuit. 
   
   
       24 . A continuous hot water supply system connectable to a water supply line and to a flow circuit having a hot water supply line, and a hot water return line connected to the hot water supply line, comprising:
 a water heating assembly coupled to the water supply line, wherein at least a portion of the water supply line extends from the water heating assembly;   a reservoir remote from the water heating assembly and positioned to receive heated water from the water heating assembly, the reservoir having a first inlet and a first outlet, the first outlet being connectable to the hot water supply line; and   a circulation device in fluid communication with the reservoir, the circulation device having a second inlet connectable to the water supply line to receive water therefrom, the circulation device having a second outlet in fluid connection with at least one of the water heating assembly and the reservoir, the circulation device having at least one return inlet connectable to the hot water return line and configured to allow a substantially continuous flow of return hot water therethrough driven by convection forces without the benefit of a recirculation pump, and a valve connected to the return inlet and being moveable between open and closed positions, the valve in the open position allowing recirculated hot water to flow into the chamber from the return line, and the valve in the closed position blocking water from flowing from the chamber through the return line.   
   
   
       25 . The continuous hot water supply system of  claim 24  wherein the water heating assembly is a tankless water heater. 
   
   
       26 . The continuous hot water supply system of  claim 24  wherein the reservoir includes a heating element activatable to heat water contained in the reservoir. 
   
   
       27 . The continuous hot water supply system of  claim 24  wherein the circulation device is positioned immediately adjacent to the reservoir. 
   
   
       28 . The continuous hot water supply system of  claim 24  wherein the circulation device is positioned immediately adjacent to and upstream from the water heating assembly. 
   
   
       29 . The continuous hot water supply system of  claim 24  wherein the second inlet of the circulation device is connected to the portion of the water supply line, and the second outlet of the circulation device is connected to the first inlet of the reservoir.