WO2011060524A1

WO2011060524A1 - Water heating system

Info

Publication number: WO2011060524A1
Application number: PCT/CA2009/001682
Authority: WO
Inventors: Giuseppe Mlnnella
Original assignee: Aloha Energy Solution Inc.
Priority date: 2009-11-20
Filing date: 2009-11-20
Publication date: 2011-05-26
Also published as: TW201144721A

Abstract

A water heating system has a boiler (12), a chimney (28) connected to the boiler and at least one conduit (42) connected to a municipal water supply by a valve (39) and positioned such that heat from the exhaust gases in the chimney is transferred to water in the at least one conduit (42). A tank (14) having a tank outlet (178) for supplying heated water receives water from the at least one conduit (58). One of hot water or steam being supplied by the boiler flows through a heat exchanger (18) and back to the boiler (12) inlet (30) by way of the condensate tank (16). Water in the tank (14) flows to and through the heat exchanger (20) via an inlet (80) and strainer (84) and back to the tank via outlet (86), heat exchanger (18) and line (108) such that heat from the one of hot water or steam being supplied by the boiler and flowing through the heat exchangers (18, 20) is transferred to the water. A valve (140) fluidly connects the boiler ((12) and the heat exchanger (18) when the temperature of the water in the tank (14) is below a predetermined value. In a second embodiment using a condensate tank (16), water from tank (14) flows through a heat exchanger (202) when the temperature of the water in tank (14) as sensed by sensor (68) falls below a predetermined value so that it may be heated by exchange with heat from water in the condensate tank (16). Heat from a solar heating system (250) may be exchanged to water in tank (252) via heat exchanger (262). Hot water, (mixing valve (290) adjusted to a predetermined temperature), is sent from tank (252) to tank (14) via pipe (72). Magnetic systems are used to enhance the entropy of fuel/air flows.

Description

WATER HEATING SYSTEM

FIELD OF THE INVENTION

[0001] The present invention relates to water heating systems.

BACKGROUND OF THE INVENTION [0002] Various types of water heating systems exist in order to address various applications and levels of hot water demand.

[0003] One type of water heating system has a tank for storing water. A heat exchanger is used to heat the water in the tank. This type of system relies upon slow rates of heating of large volumes of water in the tank to maintain the water at a desired temperature. However, this type of water heating system is not well suited for applications involving large draws of water since it takes a long time to raise the temperature of water to the desired temperature.

[0004] Another type of water heating system, known as an instantaneous water heater, has no significant storage for the heated water and relies on a large heat exchanger to provide hot water quickly. However, this type of water heating system makes it difficult to control the temperature of the hot water being supplied since this temperature depends on the flow rate of the water through the heat exchanger, and therefore on the demand for hot water.

[0005] Some water heating systems use a boiler to generate steam or hot water. Boilers rely on combustion to generate the steam or hot water and as such generate polluting exhaust gases.

[0006] United States Patent 4,046,189, issued September 6, 1977, United

States Patent 4,305,547, issued December 15, 1981 , and United States Patent 6,983,723 B2, issued January 10, 2006 disclose various water heating systems which use steam to heat cold water.

[0007] Therefore, there is a need for a water heating system well suited for applications involving large draws of water. [0008] There is also a need for a water heating system which can supply hot water quickly while providing adequate control of the temperature of the water.

[0009] There is also a need for a water heating system which is energy efficient and has reduced exhaust emissions. SUMMARY OF THE INVENTION

[0010] It is an object of the present invention to ameliorate at least some of the inconveniences present in the prior art.

[0011] It is also an object of the present invention to provide a water heating system having a boiler, a tank, and a heat exchanger. The water heating system heats the water from a water supply using the heat of the exhaust gases of the boiler prior to supplying the water to the tank. Steam or hot water, as the case may be, from the boiler is used to heat water from the water tank in the heat exchanger when the temperature of the water in the tank drops below a predetermined temperature.

[0012] In one aspect, the invention provides a water heating system having a boiler supplying one of hot water and steam via a boiler outlet, a chimney connected to the boiler for evacuating exhaust gases of the boiler, and at least one conduit having a conduit inlet and a conduit outlet. The conduit inlet of the at least one conduit is fluidly connected to a water supply. The at least one conduit is positioned such that heat from the exhaust gases in the chimney is transferred to water in the at least one conduit. A tank is fluidly connected to the conduit outlet of the at least one conduit to receive water from the at least one conduit. The tank has a tank outlet for supplying heated water from the tank. A heat exchanger has a first heat exchanger inlet, a first heat exchanger outlet, a second heat exchanger inlet, and a second heat exchanger outlet. The first heat exchanger inlet is fluidly connected to the boiler outlet. The first heat exchanger outlet is fluidly connected to a boiler inlet of the boiler. The second heat exchanger inlet is fluidly connected to the tank. The second heat exchanger outlet is fluidly connected to the tank. The one of the hot water and steam being supplied by the boiler flows from the boiler outlet to the first heat exchanger inlet, through the heat exchanger to the first heat exchanger outlet, and back to the boiler via the boiler inlet. Water in the tank flows to the second heat exchanger inlet, through the heat exchanger to the second heat exchanger outlet, and back to the tank such that heat from the one of the hot water and steam being supplied by the boiler and flowing through the heat exchanger is transferred to the water. A valve is fluidly connected between the boiler outlet and the first heat exchanger inlet for selectively fluidly communicating the boiler outlet and the first heat exchanger inlet. The valve permits the flow of the one of the hot water and steam being supplied by the boiler when a temperature of the water in the tank is below a predetermined temperature.

[0013] In a further aspect, a mixing valve has two inlets and one outlet. One of the two inlets is fluidly connected to the tank outlet. An other one of the two inlets is fluidly connected to the water supply. The mixing valve controls flow of water through the two inlets such that water is supplied at a predetermined temperature via the outlet of the mixing valve.

[0014] In an additional aspect, a mixing valve has two inlets and one outlet.

One of the two inlets is fluidly connected to the conduit outlet. An other one of the two inlets is fluidly connected to the water supply. The mixing valve controls flow of water through the two inlets such that water is supplied to the tank at a predetermined temperature via the outlet of the mixing valve.

[0015] In a further aspect, the at least one conduit is coiled around the chimney.

[0016] In an additional aspect, the conduit inlet is disposed downstream of the conduit outlet relative to a direction of flow of the exhaust gases through the chimney.

[0017] In a further aspect, the at least one conduit is three conduits.

[0018] In an additional aspect, a pump is fluidly connected between the tank and the second heat exchanger inlet to pump water from the tank to the heat exchanger. [0019] In a further aspect, the one of the hot water and steam being supplied by the boiler flows through the heat exchanger in a direction opposite to a direction of flow of water from the tank through the heat exchanger.

[0020] In an additional aspect, the heat exchanger is a plate heat exchanger. [0021] In a further aspect, the heat exchanger is a first heat exchanger. A second heat exchanger has a third heat exchanger inlet, a third heat exchanger outlet, a fourth heat exchanger inlet, and a fourth heat exchanger outlet. Solar tubes are fluidly connected between the third heat exchanger inlet and the third heat exchanger outlet. A pump is fluidly connected between the solar tubes and the second heat exchanger for circulating water from the solar tubes to the third heat exchanger inlet, through the second heat exchanger to the third heat exchanger outlet, and back to the solar tubes. The fourth heat exchanger inlet is fluidly connected to at least one of the conduit outlet and the water supply. The fourth heat exchanger outlet is fluidly connected to the tank. Water from the at least one of the conduit outlet and the water supply flows to the fourth heat exchanger inlet, through the heat exchanger to the fourth heat exchanger outlet, and then to the tank such that heat of water from the solar tubes flowing through the second heat exchanger is transferred to the water from the at least one of the conduit outlet and the water supply. [0022] In an additional aspect, the water from the solar tubes flows through the second heat exchanger in a direction opposite to a direction of flow of water from the at least one of the conduit outlet and the water supply through the second heat exchanger.

[0023] In a further aspect, the tank is a first tank. A second tank is fluidly connected to the at least one of the conduit outlet and the water supply and to the second heat exchanger. Water from the at least one of the conduit outlet and the water supply flows to the second tank prior to flowing to the fourth heat exchanger inlet. Water from the fourth heat exchanger outlet flows to the second tank prior to flowing to the first tank. [0024] In an additional aspect, a pump is fluidly connected between the second tank and the fourth heat exchanger inlet to pump water from the second tank to the second heat exchanger.

[0025] In a further aspect, the first and second heat exchangers are plate heat exchangers. [0026] In an additional aspect, the one of hot water and steam being supplied by the boiler is steam. A condensate tank is fluidly connected between the first heat exchanger outlet and the boiler inlet, such that water flows to the condensate tank from the first heat exchanger outlet prior to flowing to the boiler.

[0027] In a further aspect, a valve selectively fluidly connects the second heat exchanger outlet with the condensate tank. The valve fluidly connects the second heat exchanger outlet with the condensate tank to supply water from the second heat exchanger outlet to the condensate tank when a level of water in the condensate tank is below a predetermined level.

[0028] In an additional aspect, a valve selectively fluidly connects the boiler outlet with the condensate tank. The valve fluidly connects the boiler outlet with the condensate tank to supply steam from the boiler outlet to the condensate tank when a temperature of water in the condensate tank is below a predetermined temperature.

[0029] In a further aspect, the heat exchanger is a first heat exchanger. A second heat exchanger has a third heat exchanger inlet, a third heat exchanger outlet, a fourth heat exchanger inlet, and a fourth heat exchanger outlet. The third heat exchanger inlet is fluidly connected to the condensate tank. The third heat exchanger outlet is fluidly connected to the condensate tank. The fourth heat exchanger inlet is fluidly connected to the tank. The fourth heat exchanger outlet is fluidly connected to the second heat exchanger inlet. Water in the condensate tank flows from the condensate tank to the third heat exchanger inlet, through the second heat exchanger to the third heat exchanger outlet, and back to the condensate tank. Water in the tank flows to the fourth heat exchanger inlet, through the second heat exchanger to the fourth heat exchanger outlet, and to the second heat exchanger inlet such that heat from the water being supplied by the condensate tank and flowing through the second heat exchanger is transferred to the water. [0030] In an additional aspect, a first pump is fluidly connected between the tank and the fourth heat exchanger inlet to pump water from the tank to the second and first heat exchangers. A second pump is fluidly connected between the condensate tank and the third heat exchanger inlet to pump water from the condensate tank to the second heat exchanger. [0031] In a further aspect, the first and second heat exchangers are plate heat exchangers. [0032] In an additional aspect, the water from the condensate tank flows through the second heat exchanger in a direction opposite to a direction of flow of water from the tank through the second heat exchanger.

[0033] In a further aspect, the condensate tank is fluidly connected between the first heat exchanger inlet and the first heat exchanger outlet. Water flows from the condensate tank to the first heat exchanger inlet, through the heat exchanger to the first heat exchanger outlet and back to the condensate tank when steam is not supplied to the first heat exchanger inlet.

[0034] In an additional aspect, a first pump is fluidly connected between the tank and the second heat exchanger inlet to pump water from the tank to the heat exchanger. A second pump is fluidly connected between the condensate tank and the first heat exchanger inlet to pump water from the condensate tank to the first heat exchanger inlet.

[0035] In a further aspect, the boiler has a gas supply line and an air intake to supply gas and air, respectively, to be combusted by the boiler in order to heat water in the boiler. At least one of the gas supply line and the air intake is subjected to a magnetic field.

[0036] In an additional aspect, both the gas supply line and the air intake are subjected to magnetic fields. [0037] In a further aspect, a plurality of magnets are disposed near the air intake.

[0038] In an additional aspect, a plurality of permanent magnets are disposed adjacent a portion of the gas line.

[0039] In a further aspect, a housing surrounds the plurality of permanent magnets and the portion of the gas line.

[0040] In an additional aspect, the housing is made of non-magnetic material.

[0041 ] In a further aspect, the non-magnetic material is aluminum. [0042] In a further aspect, a core material is disposed between the housing and the portion of the gas line. The core material defines a plurality of chambers receiving the plurality of permanent magnets.

[0043] In an additional aspect, the core material is a polymer. [0044] In a further aspect, a plurality of plugs are disposed in the core material and are in contact with the plurality of permanent magnets to help maintain the plurality of permanent magnets in place.

[0045] In an additional aspect, at least one permanent magnet is disposed on a first side of the portion of the gas line and at least one permanent magnet is disposed on a second side of the portion of the gas line diametrically opposite the first side.

[0046] In a further aspect, the polarity of the at least one permanent magnet disposed on the first side is the same as the polarity of the at least one permanent magnet of the second side.

[0047] In an additional aspect, the at least one permanent magnet on the first side is two longitudinally aligned permanent magnets being arranged with ends of opposite polarities facing each other, and the at least one permanent magnet on the second side is two longitudinally aligned permanent magnets being arranged with ends of opposite polarities facing each other.

[0048] For purposes of this application, the term "conduit" refers to an element for conveying fluid from one point to another. A conduit can be made of a single pipe or tube, multiple pipes or tubes, and a combination of pipes, tubes and elbows, junctions, unions, or any other device used to convey fluid from one point to another. For example, as can be seen in Fig. 1 , the conduit 110 is made of three pipes and two elbows, the conduit 134 is made of two pipes and one union, and the conduit 62 is made of a single pipe.

[0049] Embodiments of the present invention each have at least one of the above-mentioned object and/or aspects, but do not necessarily have all of them. It should be understood that some aspects of the present invention that have resulted from attempting to attain the above-mentioned object may not satisfy these objects and/or may satisfy other objects not specifically recited herein.

[0050] Additional and/or alternative features, aspects, and advantages of embodiments of the present invention will become apparent from the following description, the accompanying drawings, and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0051] For a better understanding of the present invention, as well as other aspects and further features thereof, reference is made to the following description which is to be used in conjunction with the accompanying drawings, where: [0052] Figure 1 illustrates a first embodiment of a water heating system;

[0053] Figure 2 is a close-up view of the condensate tank and heat exchangers area of the water heating system of Figure 1 ;

[0054] Figure 3 illustrates a second embodiment of a water heating system;

[0055] Figure 4 is a close-up view of the condensate tank and heat exchanger area of the water heating system of Figure 3;

[0056] Figure 5 illustrates a solar water heating system that can be added to the water heating systems of Figures 1 and 3;

[0057] Figure 6 is a schematic representation of an air intake device of a boiler used in the water heating systems of Figures 1 and 3; [0058] Figure 7 is a perspective view of a gas treating device, shown with a housing thereof in an opened position, and of a portion of a gas supply line of the boiler used in the water heating systems of Figures 1 and 3; and

[0059] Figure 8 is a cross-sectional view of the gas treating device of Figure 7, shown with the housing thereof in a closed position, with a portion of the gas supply line disposed therein. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0060] The water heating systems described below will be described using a steam boiler which supplies steam, however it is contemplated that, for at least certain aspects of the invention, a hot water boiler which supplies hot water could be used instead.

[0061] Figs. 1 and 2 illustrate a first embodiment of a water heating system

10. As can be seen, the system 10 includes a boiler 12, a water tank 14, a condensate tank 16, and a pair of heat exchangers 18, 20. The tank 14 is a stainless steel insulated water tank, however it is contemplated that other types of tanks could be used. [0062] The boiler 12 is a steam boiler for supplying steam, however it is contemplated, as discussed above, that the boiler 12 could be a hot water boiler supplying hot water. The boiler 12 burns natural gas, or other combustible, from a gas supply. Gas is supplied from the gas supply via a gas supply line 22. A portion of the gas supply line 22 is surrounded by a gas treating device 24 described in greater detail below. Air for the combustion process is supplied by an air intake device 26 also described in greater detail below. The exhaust gases resulting from the combustion process are evacuated via a chimney 28. Water is supplied to the boiler 12 from the condensate tank 16 via a boiler inlet 30, as described in greater detail below. Water in the boiler 12 is heated and transformed to steam by a burner (not shown) combusting the gas. Steam from the boiler 12 is supplied to other portions of the system 10 via a boiler outlet 32, as described in greater detail below. It is contemplated that steam could also be supplied from the boiler 12 for other applications. For example, steam could be supplied for commercial applications such as in dry cleaners. The boiler 12 also has a control panel 34, a pump control 36, and a blowdown 38 for releasing steam from the boiler 12, which will not be described in detail herein as they are believed to be well known by those skilled in the art of boilers.

[0063] Cold water is fed to the water heating system 10 from a water supply, such as a municipal water supply network. A valve 39 is used to open or close the supply of water from the water supply to the system 10. The valve 39 is a manually actuated ball valve, however it is contemplated that any suitable type of valve could be used. When the valve 39 is opened, water from the water supply then flows through two check valves 40 and enters conduit 42. The two check valves 40 prevent water from flowing back to the water supply from the system 10. It is contemplated that only one check valve 40 could be used. An expansion chamber 44 is connected to the conduit 42. The expansion chamber 44 helps prevent water hammer. A hydraulic separator 45 assists in removing unwanted air and dirt from the water.

[0064] From the conduit 42, water flows to the inlet of a water manifold 46 which splits the water from the conduit 42 into three conduits 48 made of a material having good heat conductivity, such as copper. As can be seen, the three conduits 48 are pipes coiled around the chimney 28 such that water flows from the conduit 42, into the water manifold 46, then down around the chimney 28 via conduits 48, into another water manifold 50. The water manifold 50 takes the water from the three conduits 48 and supplies it via a single outlet to a conduit 52.

[0065] By having the water flow in the conduits 48 as described above, heat from the exhaust gases generated by the combustion process in the boiler 12 is transferred to the water in the conduits 48. This has the advantage of pre-heating the water before supplying it to the tank 14 by using energy which would otherwise be wasted, thus making the system 10 more efficient. By modifying the length and diameter of the conduits 48, the material used to make the conduits 48 and the chimney 28 (thereby increasing or decreasing the heat conductivity of the materials used), and/or by changing the flow rate of the water inside the conduits 48 and of the exhaust gases in the chimney 28, the more or less heat can be transferred to the water inside the conduits 48. It is contemplated that more or less than three conduits 48 could be used. It is also contemplated that the conduits 48 could not be coiled around the chimney 28 but be otherwise positioned near or in contact with the chimney 28 so as to absorb heat from the exhaust gases in the chimney 28. Also, the efficiency of the heat transfer is increased by having the water flow in the conduits 48 in a direction (i.e. down) opposite to the direction of the flow of the exhaust gases in the chimney 28 (i.e. up). As can be seen, in the present embodiment the inlet to the conduits 48 is disposed downstream of the outlet to the conduits 48 relative to a direction of flow of the exhaust gases through the chimney 28, thus creating a countercurrent flow between the water in the conduits 48 and the exhaust gases. It is contemplated that two ring magnets could be disposed around the chimney 28 downstream of the conduits 48 relative to a direction of flow of the exhaust gases through the chimney 28 in order to cool the exhaust gases further before they exit to the atmosphere.

[0066] A pressure release valve 54 is connected to the conduit 52. The pressure release valve 54 opens when the pressure inside the conduit 52 exceeds a predetermined level above which the system 10 could become damaged. From the conduit 52, the water flows through two check valves 56. The two check valves 56 prevent water from flowing back to the conduits 48. It is contemplated that only one check valve 56 could be used. From the check valves 56, water flows inside a conduit 58 to a mixing valve 60.

[0067] The mixing valve 60 has two inlets. One inlet receives the pre-heated water from the conduit 58. The other inlet receives cold water from a conduit 62 which branches off from the conduit 42. The mixing valve 60 adjusts the amount of water entering the valve 60 from the conduits 58 and 62 in order to control the temperature of the water exiting the valve 60 to a conduit 64. The conduit 64 then supplies water to the tank 14 in a lower portion thereof. The mixing valve 60 is connected to an electronic control unit 66. The electronic control unit 66 is connected to a temperature probe 68 that senses the temperature of the water in the tank 14. Based on the temperature sensed by the probe 68, the control unit 66 sends a signal to the mixing valve 60 to adjust the level of water flowing from each of the conduits 58 and 62 to the conduit 64 in order to control the temperature of the water entering the tank 14.

[0068] The mixing valve 60 may also supply water to a conduit 70 which in turn supplies water to an optional solar water heating system 250 (Fig. 5) that can be added to the water heating system 10. Water is returned to the tank 14 from the solar water heating system 250 via a conduit 72. The solar water heating system 250 will be described in greater detail below.

[0069] The water tank 14 has a manually actuated valve 74, such as a needle valve, connected to a lower portion thereof to permit the drainage of the water in the water tank 14. The water tank 14 is selectively connected to a drain conduit 76 via a release valve 78. The release valve 78 opens in the event that the temperature inside the tank 14 exceeds a predetermined temperature, thus permitting water in the tank 14 to drain out of the tank 14 via the conduit 76, thereby reducing the pressure in the tank 14.

[0070] To heat water in the water tank 14, water is pumped from the tank 14 to an inlet 80 of the heat exchanger 20 by a circulator pump 82. A strainer 84 is disposed between the tank 14 and the inlet 80 of the heat exchanger 20 to prevent deposits present in the water to enter the heat exchanger 20. The water then flows through the heat exchanger 20 to an outlet 86 (see Fig. 2) of the heat exchanger 20. Hot water is supplied to the heat exchanger 20 from the condensate tank 16. The manner in which hot water is supplied to the condensate tank 16 will be described in greater detail below. Hot water is pumped from the condensate tank 16 to another inlet 88 of the heat exchanger 20 by another circulator pump 90 via a conduit 92. It is contemplated that a device having magnets similar to the air intake device 26 described below and a strainer similar to the strainer 84 described above could be added to the conduit 92 to help prevent minerals and deposits present in the water from clogging the heat exchanger 20. The water then flows through the heat exchanger 20 to another outlet 94 of the heat exchanger 20 and is then returned to the condensate tank 16 via a conduit 96. In the present embodiment, the heat exchanger 20 is a plate heat exchanger, however other types of heat exchangers are contemplated. As can be seen, the water supplied from the water tank 14 to the heat exchanger 20 flows through the heat exchanger 20 in a direction opposite to a direction of flow of water supplied from the condensate tank 16 through the heat exchanger 20. As the water from the water tank 14 flows through the heat exchanger 20, it absorbs heat from the water flowing through the heat exchanger 20 from the condensate tank 16. Therefore, the temperature of the water exiting the heat exchanger 20 at the outlet 86 is hotter than the water entering the heat exchanger 20 at the inlet 80. The pumps 82 and 90 are connected to the electronic control unit 66. When the temperature sensed by the probe 68 falls below a predetermined temperature, the control unit 66 sends a signal to the pumps 82 and 90 in order to operate the pumps 82 and 90 such that water from the tanks 14 and 16 flows through the heat exchanger 20 in order to heat water from the water tank 14. [0071] From the outlet 86 of the heat exchanger 20 the water flows via a conduit 98 to an inlet 100 of the heat exchanger 18. The water then flows through the heat exchanger 18 to an outlet 102 of the heat exchanger 18. Steam is supplied to the heat exchanger 18 from the boiler 12 as described in greater detail below. Steam enters the heat exchanger 18 via another inlet 104 of the heat exchanger 18. The steam then flows through the heat exchanger 18 to another outlet 106 of the heat exchanger 18 where it exits the heat exchanger 18 as condensate. In the present embodiment, the heat exchanger 18 is a plate heat exchanger, however other types of heat exchangers are contemplated. As can be seen, the water supplied from the heat exchanger 20 to the heat exchanger 18 flows through the heat exchanger 18 in a direction opposite to a direction of flow of steam supplied from the boiler 12 through the heat exchanger 18. As the water from the heat exchanger 20 flows through the heat exchanger 18, it absorbs heat from the steam flowing through the heat exchanger 18 from the boiler 12. Therefore, the temperature of the water exiting the heat exchanger 18 at the outlet 102 is hotter than the water entering the heat exchanger 18 at the inlet 100. As will be described in more detail below, steam is selectively supplied to the heat exchanger 18 based on the temperature of the water inside the tank 14. Steam is supplied to the heat exchanger 18 when the temperature of the water inside the tank 14 falls below a predetermined temperature and when fast heating of the water from the tank 14 is necessary, such as when starting up the water heating system 10 after an extended period of inactivity, or when there is a high demand for hot water. It is contemplated however that steam could be supplied to the heat exchanger 18 at any other time to supplement the heating of the water by the heat exchanger 20 or for heating the water from the tank 14 using the heat exchanger 18 without using condensate to heat water in the heat exchanger 20.

[0072] From the outlet 102 of the heat exchanger 18, the hot water flows back to an upper portion of the water tank 14 via a conduit 108. A conduit 1 10 branches off the conduit 108. An electronically controlled valve 112 disposed between the conduits 108 and 110 selectively communicates the conduits 108 and 110 to supply water to the condensate tank 16. The valve 112 is connected to a float valve 114 in the condensate tank 16 which sends a signal to the valve 112 to open when the level of water (condensate) in the condensate falls below a predetermined level. A combined water pressure and temperature gauge 116 is disposed on the conduit 108 upstream of the conduit 110 to provide a visual indication of the water pressure and temperature at this location. Another combined water pressure and temperature gauge 118 is disposed on the conduit 108 downstream of the conduit 110 to provide a visual indication of the water pressure and temperature at this location. [0073] The steam and condensate circuit of the water heating system 10 will now be described in more detail. From the boiler outlet 32, the steam flows through a conduit 120. A conduit 122 branches off the conduit 120. A self-operating temperature regulator 124 having a temperature probe 126 disposed in the condensate tank 16 communicates the conduit 122 with the condensate tank 16 when a temperature of the condensate falls below a predetermined temperature. As a result, steam is supplied from the conduit 122 to the condensate tank 16 below a level of the condensate in order to increase the temperature of the condensate up to the predetermined temperature. It is contemplated that the self-operating temperature regulator 124 could be replaced by other types of temperature controlled valves. [0074] A self-operating temperature regulator 128 having a temperature probe

130 disposed in the water tank 14 controls the flow of steam from the conduit 120 to a conduit 132. When a temperature of the water in the water tank 14 falls below a predetermined temperature, the temperature regulator 128 permits the flow of steam from the conduit 120 to the conduit 132. It is contemplated that the self-operating temperature regulator 128 could be replaced by other types of temperature controlled valves.

[0075] When the temperature regulator 128 permits the flow of steam from the conduit 120 to the conduit 132, the steam flows from the conduit 132 to a conduit 134. A valve 136 is used to manually open or close the supply of steam from the conduit 132 to the conduit 134. The valve 136 is a manually actuated ball valve, however it is contemplated that any suitable type of valve could be used. From the conduit 134, steam flows through a pressure reducing valve 138. A solenoid valve 140 is disposed downstream of the pressure reducing valve 138 to permit or prevent the passage of steam to the heat exchanger 18. The solenoid valve 140 is connected to the control unit 66. The control unit 66 sends a signal to the solenoid valve 140 to open when the temperature sensed by the probe 68 is below a predetermined temperature. It is contemplated that the solenoid valve 140 could be replaced by any other suitable electronically controlled valve. When the solenoid valve 140 is opened, steam flows from the solenoid valve 140 to the inlet 104 of the heat exchanger 1 8. A steam pressure indicator 142 is disposed downstream of the solenoid valve 140 to provide a visual indication of the steam pressure at this location. A valve 143 is used to manually open or close the supply of steam to the steam pressure indicator 142. The valve 143 is a manually actuated ball valve, however it is contemplated that any suitable type of valve could be used. A pressure release valve 144 is disposed downstream of the steam pressure indicator 142. The pressure release valve 1 4 opens when the steam pressure downstream of the valve 140 exceeds a predetermined level above which the system 10 could become damaged.

[0076] As described above, once the steam reaches the inlet 104 of the heat exchanger 18, it flows through the heat exchanger 1 8 and exits at the outlet 106. From the outlet 106, it flows through a thermodynamic trap 146 and a check valve 148. From the check valve 148, water (i.e. the condensate of the steam) flows through a conduit 150 to the condensate tank 16. The check valve 148 prevents the water from flowing back toward the heat exchanger 18.

[0077] As described above, the condensate tank 16 receives water (in various states) from various points in the water heating system 10. As best seen in Fig. 2, the condensate tank 1 6 has a one-way valve 152 disposed on the top thereof to permit air to flow inside the condensate tank 16. A conduit 154 connected to the side of the condensate tank 16 above the level of condensate in the tank 16 acts as a vent for the condensate tank 16.

[0078] As also described above, water is supplied to the boiler 12 from the condensate tank 16. A drain conduit 156 is connected to the bottom of the condensate tank 16. A manually actuated valve 158, such as a needle valve, is connected to the drain conduit to permit the drainage of the water in the condensate tank 16. A conduit 160 branches off the drain conduit 156 to connect the condensate tank 16 to a boiler feed pump 162. The boiler feed pump 162 pumps water from the condensate tank 16 to the boiler inlet 30. The operation of the pump 162 is controlled by the pump control 36 of the boiler 12. Two check valves 164 disposed downstream of the pump 162 prevent water from flowing back toward the pump 162. A manually actuated valve 166, such as a needle valve, disposed downstream of the check valves 164 is used to control the flow of water to the boiler 12. A valve 168 is used to manually open or close the supply of water to drain conduit 156, and therefore to the boiler 12. The valve 168 is a manually actuated ball valve, however it is contemplated that any suitable type of valve could be used. [0079] To supply hot water from the water heating system 10, water exits the water tank 14 via a water tank outlet 170. From the water tank outlet 170, water flows through a conduit 172 to a mixing valve 174. The mixing valve 174 has two inlets. One inlet receives the heated water from the conduit 172. The other inlet receives water from a conduit 176 which branches off from the conduit 64. The mixing valve 174 adjusts the amount of water entering the valve 174 from the conduits 172 and 176 in order to control the temperature of the water exiting the valve 1 74 to a conduit 178. The conduit 178 then supplies hot water to one or more devices demanding hot water (such as a hot water tap, sauna, etc.). The mixing valve 174 is connected to the electronic control unit 66. Based at least on the temperature sensed by the probe 68, the control unit 66 sends a signal to the mixing valve 174 to adjust the amount of water flowing from each of the conduits 172 and 176 to the conduit 178 in order to control the temperature of the water supplied.

[0080] Turning now to Figs. 3 and 4, a second embodiment of a water heating system 200 will be described. For simplicity, elements of the water heating system 200 which are similar to those of the water heating system 10 described above with respect to Figs. 1 and 2 have been labeled with the same reference numerals and will not be described again.

[0081 ] In the water heating system 200, water is supplied from the water supply to the water tank 14 in the same way as in the water heating system 10 described above. As can be seen in Figs. 3 and 4, the water heating system 200 has only one heat exchanger 202. In the present embodiment, the heat exchanger 202 is a plate heat exchanger, however other types of heat exchangers are contemplated. To heat water in the water tank 14, water is pumped from the tank 14 to an inlet 204 of the heat exchanger 202 by a circulator pump 206. A strainer 208 is disposed between the tank 14 and the inlet 204 of the heat exchanger 202 to prevent deposits present in the water to enter the heat exchanger 202. The water then flows through the heat exchanger 202 to an outlet 210 of the heat exchanger 202. [0082] Steam is supplied to the heat exchanger 202 from the boiler 12 in the same way as in the water heating system 10 described above. Steam enters the heat exchanger 202 via another inlet 212 of the heat exchanger 202. The steam then flows through the heat exchanger 202 to another outlet 214 of the heat exchanger 202 where it exits the heat exchanger 202 as condensate where it is returned to the condensate tank 16 as in the water heating system 10 described above. As can be seen, the water supplied from the water tank 14 to the heat exchanger 202 flows through the heat exchanger 202 in a direction opposite to a direction of flow of steam supplied from the boiler 12 through the heat exchanger 202. [0083] A conduit 216 is connected to a bottom of the condensate tank 16. An electronically controlled valve 218 selectively connects the conduit 216 to a conduit 220 which is connected to the outlet 214 of the heat exchanger 202. It is contemplated that a device having magnets similar to the air intake device 26 described below and a strainer similar to the strainer 208 described above could be added to the conduit 216 to help prevent minerals and deposits present in the water from clogging the heat exchanger 202. A conduit 222 is connected to an inlet 212 of the heat exchanger 202. Another electronically controlled valve 224 selectively connects the conduit 222 to a conduit 226 which is connected to the condensate tank 16. [0084] The valves 218 and 224 are connected to the control unit 66 which sends signals to the valves 218 and 224 to open or close. When steam is being supplied to the heat exchanger 202 as described above, the valves 218 and 224 are closed to prevent water to flow to the heat exchanger 202 from the condensate tank 16 and to prevent steam from entering the condensate tank via the conduit 222. [0085] When steam is not being supplied to the heat exchanger, by closing one of the valves 128, 136, and 140, the valves 218 and 224 are opened and hot water is supplied to the heat exchanger 202 from the condensate tank 16. Hot water is pumped from the condensate tank 16 to the outlet 214 of the heat exchanger 202 by another circulator pump 228 via the conduits 216 and 220. The water then flows through the heat exchanger 202 to the inlet 212 of the heat exchanger 202 and is then returned to the condensate tank 16 via the conduits 222 and 226. As can be seen, the water supplied from the water tank 14 to the heat exchanger 202 flows through the heat exchanger 202 in the same direction as the water supplied from the condensate tank 16 through the heat exchanger 202.

[0086] As the water from the water tank 14 flows through the heat exchanger

202, it absorbs heat from the steam from the boiler 12 or from the water from the condensate tank 16, as the case may be, flowing through the heat exchanger 202. Therefore, the temperature of the water exiting the heat exchanger 202 at the outlet 210 is hotter than the water entering the heat exchanger 202 at the inlet 204. From the outlet 210, water is returned to the water tank 14 as in the water heating system 10 described above. [0087] Water from the water tank 14 is made to flow through the heat exchanger 202 when the temperature of the water in the water tank 14 sensed by the sensor 68 falls below a predetermined temperature. The control unit 66 determines which of steam from the boiler 12 and water from the condensate tank 16 is to be supplied to the heat exchanger 202 based on the speed at which water needs to be heated and on the demand for hot water.

[0088] Hot water from the water heating system 200 is supplied from the tank

14 as in the water heating system 10 described above.

[0089] Turning now to Fig. 5, the optional solar water heating system 250 that can be added to either one of the water heating systems 10 and 200 will be described. Water is supplied to the water heating system 250 via the conduit 70 and is returned to the water tank 14 of the water heating system 10 or 200 via the conduit 72.

[0090] The conduit 70 supplies water to a water tank 252. The tank 252 is a stainless steel insulated water tank, however it is contemplated that other types of tanks could be used. The water tank 252 has a manually actuated valve (not shown), such as a needle valve, connected to a lower portion thereof to permit the drainage of the water in the water tank 252. The water tank 252 is selectively connected to a drain conduit 254 via a release valve 256. The release valve 256 opens in the event that the temperature inside the tank 252 exceeds a predetermined temperature, thus permitting water in the tank 252 to drain out of the tank 252 via the conduit 254, thereby reducing the pressure in the tank 252. [0091 ] To heat the water in the tank 252, a circulator pump 258 pumps water from the water tank 252 to an inlet 260 of a heat exchanger 262. The water then flows through the heat exchanger 262 to an outlet 264 of the heat exchanger 262. From the outlet 264 of the heat exchanger 262, the water flows through a conduit 266 back to the water tank 252. A separate circuit supplies heated water to the heat exchanger 262. Water is heated in solar tubes 268 by the sun. A circulator pump 270 pumps water from the solar tubes 268 through conduits 272 and 274 to another inlet 276 of the heat exchanger 262. The water then flows through the heat exchanger 262 to another outlet 278 of the heat exchanger 262. From the outlet 278, the water then flows through a conduit 280 back to the solar tubes 268. An air release valve 282 located at the highest point of this separate circuit permits any air or vapor to be released from the circuit. In the present embodiment, the heat exchanger 262 is a plate heat exchanger, however other types of heat exchangers are contemplated. As can be seen, the water supplied from the water tank 252 to the heat exchanger 262 flows through the heat exchanger 262 in a same direction as a direction of flow of water supplied from the solar tubes 268 through the heat exchanger 262. As the water from the water tank 252 flows through the heat exchanger 262, it absorbs heat from the water flowing through the heat exchanger 262 from the solar tubes 268. Therefore, the temperature of the water exiting the heat exchanger 262 at the outlet 264 is hotter than the water entering the heat exchanger 262 at the inlet 260.

[0092] The pumps 258 and 270 are connected to a temperature control valve

284 disposed between the pump 258 and the tank 252. When a temperature probe (not shown) of the temperature control valve 284 senses that the temperature of the water in the tank 252 falls below a predetermined temperature, the temperature control valve 284 opens to permit water to flow from the tank 252 to the pump 258 and sends a signal to the pumps 258 and 270 in order to operate the pumps 258 and 270 such that water from the tank 252 and from the solar tubes 268 flows through the heat exchanger 262 in order to heat water from the water tank 252.

[0093] To supply hot water from the water heating system 250 to the water heating system 10 or 200, water exits the water tank 252 via a water tank outlet 286. From the water tank outlet 286, water flows through a conduit 288 to a mixing valve 290. The mixing valve 290 has two inlets. One inlet receives the heated water from

J9 the conduit 288. The other inlet receives water from a conduit 292 which branches off from the conduit 70. The mixing valve 290 adjusts the amount of water entering the valve 290 from the conduits 288 and 292 in order to control the temperature of the water exiting the valve 290 to the conduit 72. The conduit 72 then supplies hot water to the tank 14 of the water heating system 10 or 200.

[0094] It is contemplated that the water heating components of the water heating system 250 (i.e. heat exchanger 262, solar tubes 268, pump 258 and 270, valves 282 and 284, and conduits 266, 272 and 274) could be mounted directly on the water tank 14 of the water heating system 10 or 200 instead of using the separate water tank 252.

[0095] Turning now to Fig. 6, the air intake device 26 of the boiler 12 used in the water heating systems 10 and 200 will be described. The air intake device 26 includes an air intake 300 and a plurality of permanent magnets 301 , 302 disposed near the air intake 300. As can also be seen, the polarity of the permanent magnets 301 is arranged to be the same as the polarity of the permanent magnets 302. Air enters the air intake 300 on one side thereof directly from the atmosphere or through a conduit and/or air filter, passes through the air intake 300 of the air intake device 26 and exits on the other side of the air intake 300 where it is supplied to the boiler 12 to be combusted with gas supplied by the gas supply line 22. Louvers (not shown) control the flow of air through the air intake 300. By flowing through the air intake device 26, the air, and therefore the oxygen found therein, is subjected to magnetic fields which has been found to result in a more complete or efficient combustion of the gas supplied by the gas supply line, and therefore in reduced pollution due to the combustion of the gas. [0096] In an exemplary embodiment of the air intake device 26, the air intake has a diameter of 1.905 cm {¾ in.). The magnets 301 , 302 have a width Wl of 2.54 cm (1 in.), a height HI of 1.27 cm (½ in.) (not shown) and a length L I of 5.08 cm (2 in.). Four magnets 301 , 302 are disposed on each side of the air intake 300 diametrically opposite each other. The magnets 301 , 302 are spaced from each other by a distance A l of 1 .905 cm (³A in.). The permanent magnets are 2000 Gauss neodymium magnets. It should be understood that the number, size, positioning, and type of magnets may vary depending on the dimensions of the air intake 300 and other factors. For example, by using stronger magnets, less magnets may be used and/or they may be spaced further apart from each other.

[0097] Turning now to Figs. 7 and 8, the gas treating device 24 of the boiler

12 used in the water heating systems 10 and 200 will be described. The gas treating device 24 has a housing 350. The housing 350 is made of two semi-cylindrical halves 352 connected to each other by a hinge 354 to allow the gas treating device 24 to be opened (as in Fig. 7) to install or remove the gas treating device 24 or closed (as in Fig. 8) when being used. A lock (not shown) is used to maintain the gas treating device 24 in the closed position. The housing 350 is made of non-magnetic material such as aluminum. A core material 356 is disposed inside each of the housing halves 352 so as to be disposed between the gas line 22 and the housing 350 when the gas treating device is closed as seen in Fig. 8. The core material 356 is a polymer such as polystyrene. The core material 356 defines recesses 358 to receive a portion of the gas line 22. The core material 356 also defines a plurality of chambers 360 to receive a plurality of permanent magnets 362 (362A to 362D) in a position adjacent to the gas line 22. A plurality of plugs 364 (Fig. 8), made of steel for example, are disposed in a plurality of holes 366 (Fig. 7) extending from the chambers 360 and contact the magnets 362 to help maintain the magnets 362 in place. As can be seen in Fig. 8, when the gas treating device 24 is closed around the portion of the gas line 22, the housing surrounds the portion of the gas line 22 and the permanent magnets 362.

[0098] As can be seen in Fig. 7, the permanent magnets 362A and 362B are longitudinally aligned with each other and are disposed on a diametrically opposite side of the gas line from the permanent magnets 362C and 362D, which are also longitudinally aligned with each other. As can also be seen, the polarity of the permanent magnets 362A and 362B is arranged to be the same as the polarity of the permanent magnets 362C and 362D. Also, the polarity of the permanent magnet 362A is arranged in the same direction as the polarity of the permanent magnet 362B such that the ends of the magnets 362A and 362B that face each other (i.e. the ends near the longitudinal center of the gas treating device 24) have opposite polarities. Similarly, the polarity of the permanent magnet 362C is arranged in the same direction as the polarity of the permanent magnet 362D such that the ends of the magnets 362C and 362D that face each other (i.e. the ends near the longitudinal center of the gas treating device 24) have opposite polarities.

[0099] By flowing through the portion of the gas line 22 surrounded by the gas treating device 24, the molecules of the gas, such as natural gas, or other combustible, are subjected to magnetic fields which has been found to result in a more complete or efficient combustion of the gas supplied by the gas supply line 22 to the burner (not shown) of the boiler 12, and therefore in reduced pollution due to the combustion of the gas. It has also been found that using the gas treating device 24 reduces the negative effects associated with the sulfur which is often present in the gas used for combustion in boilers .

[00100] In an exemplary embodiment of the gas treating device 24, the housing 350 has a diameter D2 of 10.16 cm (4 in.) and has a thickness Tl of 0.635 cm ( ¼ in.). The core material 356 has a diameter D3 of 8.89 cm (3 ½ in.). The recesses 358 have a combined diameter D4 of 3.81 cm (1 ½ in.) which matches an outer diameter of the gas line 22. The magnets 362 have a diameter D5 of 1.27 cm (½ in.) and a length L2 of 7.62 cm (3 in.). The magnets are disposed at a distance A2 of 1.905 cm (¾ in.) from the ends of the housing 350 and of each other in a longitudinal direction of the housing 350. The permanent magnets are 2000 Gauss neodymium magnets. It should be understood that the number, size, positioning, and type of magnets may vary depending on the dimensions of the gas supply line 22 and other factors. For example, by using stronger magnets, less magnets may be used and/or they may be spaced further apart from each other.

[00101] Modifications and improvements to the above-described embodiments of the present invention may become apparent to those skilled in the art. The foregoing description is intended to be exemplary rather than limiting. The scope of the present invention is therefore intended to be limited solely by the scope of the appended claims.

Claims

What is claimed is:

1. A water heating system comprising:

a boiler supplying one of hot water and steam via a boiler outlet;

a chimney connected to the boiler for evacuating exhaust gases of the boiler; at least one conduit having a conduit inlet and a conduit outlet, the conduit inlet of the at least one conduit being fluidly connected to a water supply, the at least one conduit being positioned such that heat from the exhaust gases in the chimney is transferred to water in the at least one conduit;

a tank fluidly connected to the conduit outlet of the at least one conduit to receive water from the at least one conduit, the tank having a tank outlet for supplying heated water from the tank;

a heat exchanger having a first heat exchanger inlet, a first heat exchanger outlet, a second heat exchanger inlet, and a second heat exchanger outlet,

the first heat exchanger inlet being fluidly connected to the boiler outlet, the first heat exchanger outlet being fluidly connected to a boiler inlet of the boiler,

the second heat exchanger inlet being fluidly connected to the tank, and the second heat exchanger outlet being fluidly connected to the tank, the one of the hot water and steam being supplied by the boiler flowing from the boiler outlet to the first heat exchanger inlet, through the heat exchanger to the first heat exchanger outlet, and back to the boiler via the boiler inlet,

water in the tank flowing to the second heat exchanger inlet, through the heat exchanger to the second heat exchanger outlet, and back to the tank such that heat from the one of the hot water and steam being supplied by the boiler and flowing through the heat exchanger is transferred to the water; and

a valve fluidly connected between the boiler outlet and the first heat exchanger inlet for selectively fluidly communicating the boiler outlet and the first heat exchanger inlet, the valve permitting the flow of the one of the hot water and steam being supplied by the boiler when a temperature of the water in the tank is below a predetermined temperature.

2. The water heating system of claim 1 , further comprising a mixing valve having two inlets and one outlet, one of the two inlets being fluidly connected to the tank outlet, an other one of the two inlets being fluidly connected to the water supply, the mixing valve controlling flow of water through the two inlets such that water is supplied at a predetermined temperature via the outlet of the mixing valve.

3. The water heating system of claim 1 , further comprising a mixing valve having two inlets and one outlet, one of the two inlets being fluidly connected to the conduit outlet, an other one of the two inlets being fluidly connected to the water supply, the mixing valve controlling flow of water through the two inlets such that water is supplied to the tank at a predetermined temperature via the outlet of the mixing valve.

4. The water heating system of claim 1 , wherein the at least one conduit is coiled around the chimney.

5. The water heating system of claim 1 , wherein the conduit inlet is disposed downstream of the conduit outlet relative to a direction of flow of the exhaust gases through the chimney.

6. The water heating system of claim 1 , wherein the at least one conduit is three conduits.

7. The water heating system of claim 1 , further comprising a pump fluidly connected between the tank and the second heat exchanger inlet to pump water from the tank to the heat exchanger.

8. The water heating system of claim 1 , wherein the one of the hot water and steam being supplied by the boiler flows through the heat exchanger in a direction opposite to a direction of flow of water from the tank through the heat exchanger.

9. The water heating system of claim 1 , wherein the heat exchanger is a plate heat exchanger.

10. The water heating system of claim 1 , wherein the heat exchanger is a first heat exchanger; and further comprising:

a second heat exchanger having a third heat exchanger inlet, a third heat exchanger outlet, a fourth heat exchanger inlet, and a fourth heat exchanger outlet;

solar tubes fluidly connected between the third heat exchanger inlet and the third heat exchanger outlet; and

a pump fluidly connected between the solar tubes and the second heat exchanger for circulating water from the solar tubes to the third heat exchanger inlet, through the second heat exchanger to the third heat exchanger outlet, and back to the solar tubes;

wherein the fourth heat exchanger inlet is fluidly connected to at least one of the conduit outlet and the water supply;

wherein the fourth heat exchanger outlet is fluidly connected to the tank; wherein water from the at least one of the conduit outlet and the water supply flows to the fourth heat exchanger inlet, through the heat exchanger to the fourth heat exchanger outlet, and then to the tank such that heat of water from the solar tubes flowing through the second heat exchanger is transferred to the water from the at least one of the conduit outlet and the water supply.

11. The water heating system of claim 10, wherein the water from the solar tubes flows through the second heat exchanger in a direction opposite to a direction of flow of water from the at least one of the conduit outlet and the water supply through the second heat exchanger.

12. The water heating system of claim 10, wherein the tank is a first tank;

further comprising a second tank fluidly connected to the at least one of the conduit outlet and the water supply and to the second heat exchanger;

wherein water from the at least one of the conduit outlet and the water supply flows to the second tank prior to flowing to the fourth heat exchanger inlet; and

wherein water from the fourth heat exchanger outlet flows to the second tank prior to flowing to the first tank.

13. The water heating system of claim 12, further comprising a pump fluidly connected between the second tank and the fourth heat exchanger inlet to pump water from the second tank to the second heat exchanger.

14. The water heating system of claim 10, wherein the first and second heat exchangers are plate heat exchangers.

15. The water heating system of claim 1 , wherein the one of hot water and steam being supplied by the boiler is steam; and

further comprising a condensate tank fluidly connected between the first heat exchanger outlet and the boiler inlet, such that water flows to the condensate tank from the first heat exchanger outlet prior to flowing to the boiler.

16. The water heating system of claim 15, further comprising a valve selectively fluidly connecting the second heat exchanger outlet with the condensate tank, the valve fluidly connecting the second heat exchanger outlet with the condensate tank to supply water from the second heat exchanger outlet to the condensate tank when a level of water in the condensate tank is below a predetermined level.

17. The water heating system of claim 15, further comprising a valve selectively fluidly connecting the boiler outlet with the condensate tank, the valve fluidly connecting the boiler outlet with the condensate tank to supply steam from the boiler outlet to the condensate tank when a temperature of water in the condensate tank is below a predetermined temperature.

18. The water heating system of claim 15, wherein the heat exchanger is a first heat exchanger; and

further comprising a second heat exchanger having a third heat exchanger inlet, a third heat exchanger outlet, a fourth heat exchanger inlet, and a fourth heat exchanger outlet,

the third heat exchanger inlet being fluidly connected to the condensate tank, the third heat exchanger outlet being fluidly connected to the condensate tank, the fourth heat exchanger inlet being fluidly connected to the tank, and the fourth heat exchanger outlet being fluidly connected to the second heat exchanger inlet,

water in the condensate tank flowing from the condensate tank to the third heat exchanger inlet, through the second heat exchanger to the third heat exchanger outlet, and back to the condensate tank,

water in the tank flowing to the fourth heat exchanger inlet, through the second heat exchanger to the fourth heat exchanger outlet, and to the second heat exchanger inlet such that heat from the water being supplied by the condensate tank and flowing through the second heat exchanger is transferred to the water.

19. The water heating system of claim 18, further comprising:

a first pump fluidly connected between the tank and the fourth heat exchanger inlet to pump water from the tank to the second and first heat exchangers; and

a second pump fluidly connected between the condensate tank and the third heat exchanger inlet to pump water from the condensate tank to the second heat exchanger.

20. The water heating system of claim 18, wherein the first and second heat exchangers are plate heat exchangers.

21. The water heating system of claim 18, wherein the water from the condensate tank flows through the second heat exchanger in a direction opposite to a direction of flow of water from the tank through the second heat exchanger.

22. The water heating system of claim 15, wherein the condensate tank is fluidly connected between the first heat exchanger inlet and the first heat exchanger outlet; wherein water flows from the condensate tank to the first heat exchanger inlet, through the heat exchanger to the first heat exchanger outlet and back to the condensate tank when steam is not supplied to the first heat exchanger inlet.

23. The water heating system of claim 22, further comprising:

a first pump fluidly connected between the tank and the second heat exchanger inlet to pump water from the tank to the heat exchanger; and a second pump fluidly connected between the condensate tank and the first heat exchanger inlet to pump water from the condensate tank to the first heat exchanger inlet.

24. The water heating system of claim 1 , wherein the boiler has a gas supply line and an air intake to supply gas and air, respectively, to be combusted by the boiler in order to heat water in the boiler; and

wherein at least one of the gas supply line and the air intake is subjected to a magnetic field.

25. The water heating system of claim 24, wherein both the gas supply line and the air intake are subjected to magnetic fields.

26. The water heating system of claim 24, further comprising a plurality of magnets disposed near the air intake.

27. The water heating system of claim 24, further comprising a plurality of permanent magnets disposed adjacent a portion of the gas line.

28. The water heating system of claim 27, further comprising a housing surrounding the plurality of permanent magnets and the portion of the gas line.

29. The water heating system of claim 28, wherein the housing is made of nonmagnetic material.

30. The water heating system of claim 29, wherein the non-magnetic material is aluminum.

31. The water heating system of claim 28, further comprising a core material disposed between the housing and the portion of the gas line, the core material defining a plurality of chambers receiving the plurality of permanent magnets.

32. The water heating system of claim 31 , wherein the core material is a polymer.

33. The water heating system of claim 31 , further comprising a plurality of plugs disposed in the core material and being in contact with the plurality of permanent magnets to help maintain the plurality of permanent magnets in place.

34. The water heating system of claim 27, wherein at least one permanent magnet is disposed on a first side of the portion of the gas line and at least one permanent magnet is disposed on a second side of the portion of the gas line diametrically opposite the first side.

35. The water heating system of claim 34, wherein the polarity of the at least one permanent magnet disposed on the first side is the same as the polarity of the at least one permanent magnet of the second side.

36. The water heating system of claim 35, wherein the at least one permanent magnet on the first side is two longitudinally aligned permanent magnets being arranged with ends of opposite polarities facing each other;

wherein the at least one permanent magnet on the second side is two longitudinally aligned permanent magnets being arranged with ends of opposite polarities facing each other.