Note: Descriptions are shown in the official language in which they were submitted.
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GAS-FIRED WATER HEATER WITH SEPARABLE HEAT EXCHANGER
OR DETACHABLY CONNECTED EXTERNAL WATER HEATER
TECHNICAL FIELD
The present invention relates to water heaters, particularly but not
exclusively, to domestic hot water heaters to which is integrated a modular
heat
exchanger or a hot water containing tank having an external water heater and
wherein
the two are easily separable from one another for service, repair or
interchange.
BACKGROUND ART
It is known to integrate heat pumps with domestic hot water heaters
wherein the hot gases are used in heat exchange with water circulated from the
hot
water heater to provide an added heat source to heat water and this usually
results in
complex devices integrated together in a single unit. A disadvantage of such
integrated
devices is that because domestic hot water heaters utilize glass-lined casings
whose
life span is usually short, and when such becomes defective it is necessary to
effect
expensive modifications or to change the entire integrated device unit instead
of only
the hot water tank. Also, maintenance of integrated systems can be expensive
depending on its structure. Accordingly, there is added fabrication costs and
service
cost when using integrated hot water systems and this cost can sometimes
obviate the
projected economical advantages of such systems. Such advantages include lower
electrical energy consumption as it is less expensive to operate a compressor
of a heat
exchanger than the electrical resistive elements of water heaters. However,
the
refrigeration system provides cool air conditioning.
With gas-fired hot water heaters there is also considerable heat loss to
the environment through the exhaust flue. There is also a need to considerably
reduce
such heat loss.
Because water tanks of domestic water heaters have a relatively short
life, it would also be beneficial to heat the water exteriorly of the tank
whereby tank
replacement would be less costly. Also, the water heater could be serviced
independently.
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SUMMARY OF INVENTION
It is a feature of the present invention to provide a water heater device
with an integrated modular heat exchanger which substantially overcomes the
above-
mentioned disadvantages of the prior art.
Another feature of the present invention is to provide a water heater
device with an integrated modular heat exchanger and wherein the water heater
and
heat exchanger are interconnected by detachable coupling means to disconnect
the
modular heat exchanger from the water heater for replacement or servicing of
the water
heater or the modular heat exchanger.
Another feature of the present invention is to provide a two-portion water
heater device, one portion being the insulated water tank and the other an
integrated
modular heat exchanger with a modulating gas power burner to heat the water
and
which is more efficient and less costly to operate than stand-alone hot water
heaters
having resistive heating elements.
Another feature of the present invention is to provide a domestic hot
water heater having an air-to-air heat exchange modular apparatus mounted on
the top
wall of the heater by detachable support means for recovering heat form the
exhaust
flue to heat the air in the environment.
Another feature of the present invention is that because the water tank
and modular heater are separable, replacement of the tank or heater can be
effected
more quickly and requiring less expenditure and inconvenience to the owner.
According to a broad aspect of the present invention there is provided a
gas-fired water heater with an integrated modular air-to-air heat exchange
apparatus.
The water heater has an insulated tank for storing water to be heated. A
combustion
chamber is provided under a lower portion of the tank and has a gas burner
therein. A
flue passageway is provided in the tank and has an outlet end exiting a top
wall of an
enclosure of the tank. The air-to-air heat exchanger is connected to the
outlet end and
constructed to communicate hot flue gases exiting the outlet end with heat
conductive
elements in contact with ambient air whereby to extract heat from the hot flue
gases
and release the heat to the ambient air. The air-to-air heat exchanger is
comprised of a
flue gas diverting assembly having an inlet chamber with a flue connecting
inlet. A
plurality of conduits are sealingly secured between the inlet chamber and an
outlet
chamber. A flue connecting outlet is secured to the outlet chamber. A
plurality of heat
sink elements are secured to the plurality of conduits to extract heat
therefrom. The
inlet chamber is a bottom chamber and the flue connecting inlet is located in
a bottom
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2A
wall thereof. The conduits are connected in a top wall of the bottom chamber
and
extend vertically thereabove. The outlet chamber is spaced above the bottom
chamber.
The flue connecting outlet is in a top wall of the outlet chamber.
According to a still further broad aspect of the present invention, there is
provided a water heater comprised of a water tank for the containment of
heated water
and an external modular water heater detachably connected to the tank to heat
water
therein. The tank has a water inlet. A hot water outlet is provided in a top
portion of the
tank. A water supply connecting means and a heated water return connecting
means is
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provided in a top portion of the water tank. The water supply connecting means
has a
water supply conduit extending to a predetermined location in the water tank.
The
heated water return connecting means has a hot water return conduit. The
modular
water heater has a gas-fired burner for heating a fluid circulated in a heat
exchanger for
heat transfer communication with cooler water circulating between the water
supply
connecting means and the heated water return connecting means.
According to a still further broad aspect of the present invention there is
provided a water heater comprised of a water tank for the containment of
heated water
and an external modular water heater detachably connected to the tank to heat
water
therein.
According to a still further broad aspect of the present invention there is
provided a water heater comprised of a water tank for the containment of
heated water
and an external modular water heater detachably connected to the tank to heat
water
therein. The modular water heater has a gas-fired burner for heating a fluid
circulated
therein in a closed conduit loop. The closed conduit loop has a portion
thereof
connected in a heat exchanger for heating water circulated in an exterior
conduit loop
having a water intake end in communication with water in a bottom region of
the tank
and a water outlet end in an upper region of the tank.
BRIEF DESCRIPTION OF DRAWINGS
A preferred embodiment of the present invention will now be described
with reference to the accompanying drawings in which:
FIG. 1 is a schematic diagram showing an integrated water
heater
device and modular heat pump constructed in accordance with the present
invention;
FIG. 2A is a perspective view, partly fragmented, of a gas-fired water
heater having an integrated modular air-to-air heat exchanger secured over a
top wall
of the water heater;
FIG. 2B is a further perspective view showing the water heater with a
fan connected to the casing of the heat exchanger to circulate the air through
the heat
exchanger and exhausted into the ambient air;
FIG. 3A is a further fragmented perspective view similar to Figure 1,
but showing a differently constructed air-to-air heat exchanger secured over
the top wall
of a conventional domestic water heater and wherein a fan is disposed in a top
wall of
the casing thereof to release heated air into the ambient air in the vicinity
of the water
heater;
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FIG. 3B is a top view showing the construction of the air-to-air heat
exchanger;
FIG. 4A is a longitudinal fragmented side view showing the
construction of a water heater comprised of a water tank for the containment
of heated
water and external modular heater detachably connected to the tank and
supported
over a top wall thereof and concealed within a casing extending co-linear with
the
housing of the domestic water heater;
FIG. 4B is a cross-section showing a heat exchanger comprised of a
concentric tube arrangement wherein hot gas or liquid within a conductive loop
is in
heat exchange with water circulated thereabout in an external conduit loop;
and
FIG. 4C is a transverse cross-section of Figure 4B.
DESCRIPTION OF PREFERRED EMBODIMENTS
Referring now to the drawings, and more particularly to Figure 1, there is
generally shown at 10 a water heater device, herein a domestic hot water
heater
device. A modular heat exchange apparatus, herein a heat pump 11 is
hereinshown
detachably mounted on the top wall 12 of the hot water heater 10 by detachable
supports 13. The supports 13 are provided with suitable detachable fastening
means
13' in a lower part thereof.
The domestic hot water heater 10 has an insulated glass lined or
stainless steel lined inner casing 14. Water is introduced in the casing by a
domestic
cold water inlet conduit 15 and released through a dip tube 16 connected
thereto in a
lower portion 17 of the inner casing 14. Hot water is extracted from the upper
portion
18 of the inner casing, where the water is the hottest, by a hot water outlet
conduit 19.
Resistive heating elements 20 and 20' are used to heat water in the upper and
lower
portion of the inner casing. The inner casing is also insulated by an
insulating foam
material (not shown) introduced in the space surrounding the inner casing and
the outer
shell 21. All of this structure is well known in the art.
As hereinshown, the modular heat pump 11 is provided with a
refrigeration system including a condensation coil 26 which has a
refrigeration conduit
26' in which is circulated a compressible gas, such as Freon. The
refrigeration conduit
26' is in contact with a water circulation conduit 27 in which cold water from
the inner
casing 14 is fed by a pump 28 which is secured to a supply conduit 29
connected to a
dip tube 30 whereby to extract cooler water from the lower portion 17 of the
inner
casing of the hot water heater 10. This supply conduit 29 is secured to the
dip tube 30
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by a detachable coupling means, such as a quick-connect coupling 31. As the
cold
water circulates through the water circulation conduit 27, it is in heat
exchange
relationship with the hot gas of the hot refrigerant in the conduit 26' and is
heated
thereby while cooling the gas. The refrigeration conduit 26' and the
circulation conduit
27 may be concentrically mounted, as for example, for heat exchange.
The heated water from the water circulation conduit 27 exits the
condensation coil 26 through a hot water supply conduit 32 and is fed to a
further dip
tube 33 which terminates inside the inner casing 14 at approximately two-
thirds (2/3)
distance down from the upper end of the inner casing 14 in a region where
water is at
an intermediate temperature whereby to introduce hot water from the heat pump.
The
hotter water propagates towards the top of the casing. The conduit 32 is
secured to the
dip tube 33 through another detachable coupling 34. Also, the cold water
conduit 15 is
secured to the dip tube 16 through a further similar detachable coupling 35
and the hot
water outlet conduit 19 is also connected to the top portion of the inner
casing by a
similar detachable coupling 36 over the top wall 12 of the outer shell 21. It
is pointed
out that the detachable couplings 31, 34, 35 and 36 are connectors capable of
being
disconnected and reconnected by a trade person whereby to easily disconnect
the
modular heat pump from the water heater for the replacement or servicing of
the water
heater or the modular heat pump, if there is a need to disconnect them. The
connectors 31, 34, 35 and 36 may be screw-type or quick connect type
connectors or
connectors that are soldered to the conduits 15, 19, 29 and 32, if such
conduits are
made of copper. Any suitable connection means is contemplated for detachment.
Because of the separable connections of both the hot water heater and
the heat pump, if the inner casing 14 becomes defective, a new hot water
heater 10
with its inner tank is replaced by the disconnection and re-connection of the
quick
connectors and the heat exchanger is secured on a new hot water heater. This
can be
done in a short time not to inconvenience the home resident. The previous hot
water
heater can then be recycled as only the inner casing needs to be changed and
the heat
pump can still be used.
As hereinshown, only basic elements of the integrated modular heat
pump 11 are illustrated. The refrigeration system includes a compressor 40 and
an
evaporator coil 41 through which ambient air is pushed through by or drawn by
a fan 25
whereby cooled dehumidified air 42 is expelled in the space where the heat
pump is
located or in conduits to convey it to other spaces in a building. The
refrigeration
system also uses an expansion valve 43 feeding the condensation coil 36. Such
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refrigeration systems are well known in the art and only the basic components
are
shown in a general fashion.
It is also foreseen that the supply conduit 30 may be located exteriorly of
the hot water heater such as illustrated by phantom lines 30' and easily
disconnected
from the hot water heater 10 by a suitable fitting (not shown) but obvious to
a person
skilled in the art.
A controller module 50 is also provided to monitor water temperature
from temperature sensors 51 and 52 located at predetermined locations inside
the tank
or inner casing 14 to monitor water temperature therein. Such is required to
control the
operation of the modular heat pump and the resistive heating elements 20 and
20' of
the inner casing 14 to satisfy user settings. A control pad 53 interfaces with
the
controller and permits a user or service person to set the desired temperature
of the
water and the mode of operation of the system.
Although the integrated heat exchange apparatus is herein described as
a modular heat pump, it is to be understood that other heat exchange apparatus
may
be coupled to the hot water device, such as a water-to-water heat exchange
apparatus
having a coil with warm circulation water therein and disposed like the
condensation coil
26 in Figure 1 for conduit 27. Such water-to-water heat exchange apparatus may
be
from chiller application, i.e., large air-conditioning systems with cooling
towers as found
in high-rise buildings.
Referring now to Figures 2A to 3A, there will be described two examples
of a gas-fired water heater 55 and 55' both of which have an integrated
modular air-to-
air heat exchange apparatus 56 ad 56'. As hereinshown, the water heater is
comprised
of an insulated water containment tank 57 and 57' for the storage of water to
be heated.
An outer skin or casing 58 and 58' surrounds the tank 57 and 57' and spaced
therefrom
wherein an insulating foam material (not shown) is disposed surrounding the
water tank
57 and 57'. The tank as hereinshown has a bottom wall 59 and 59' under which
there
is located a combustion chamber 60 and 60'. A burner assembly 61 and 61' is
located
in the combustion chamber as is well known in the art. A flue passageway 61"
and
61" extends centrally in the tank and is in communication with water contained
within
the tank to heat the water therein. The passageway has an outlet end 62 and
62' which
exits a top wall 63 of the tank and protrudes to the top wall of the outer
skin or casing
58.
As shown in Figures 2A and 2B, the air-to-air heat exchanger 56 is
connected to the outlet end 62 of the flue passageway 61 and is constructed to
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communicate hot flue gases exiting the outlet end 62 with heat conductive
elements 64
in contact with the ambient air, herein indicated by arrows 65 whereby to
extract heat
from the hot flue gases and release the heat in the ambient air by the use of
a fan 66 as
shown in Figure 2B. The air-to-air heat exchanger of Figures 3A and 3B is of
similar
construction and reference to like parts will be described simultaneously
hereinbelow.
As hereinshown, the air-to-air heat exchangers 56 and 56' are concealed in an
outer
casing housing 67 and 67'. Openings 68 are provided on one side of the outer
casing
housing 67 and 67' opposite to the fan 66 whereby the fan displaces the
ambient air 65
across the heat exchanger. The outer casing housing 67, 67' is of cylindrical
shape
and substantially of identical size as the enclosure or outer skin 58 of the
hot water
tank.
The air-to-air heat exchanger 56, as shown in Figure 2A, has a flue gas
diverting assembly 69 which has an inlet chamber 70 with a flue connecting
inlet 71. A
plurality of conduits 72 are sealingly secured between the inlet chamber 70
and an
outlet chamber 73 secured spaced thereabove. A flue connecting outlet 74 is
secured
to the outlet chamber 73. A plurality of horizontally extending heat sink
elements 75 are
secured spaced-apart to the plurality of conduits 72 to extract heat
therefrom. These
heat sink elements 75 are heat conducting plates or fins usually constructed
of
aluminum which is a good heat conductor.
As hereinshown, the inlet chamber is a bottom horizontal chamber with
the flue connecting inlet 71 being located centrally in a bottom wall 76
thereof. The
conduits 72 are connected in a top wall 77 of the bottom chamber and extend
vertically
thereabove. The outlet chamber 73 is spaced above the bottom chamber and the
flue
connecting outlet 74 is formed centrally with the top wall 78 of the outlet
chamber. As
hereinshown, the flue connecting inlet 71 is also formed with the bottom wall
76 of the
bottom chamber and extends centrally thereof for close fit sealing retention
about the
outlet end of the flue passageway and supports the air-to-air heat exchanger
thereabove and spaced from the top wall of the outer casing 58 of the tank
enclosure.
As shown in Figure 2A, a blower 79 is secured to the flue conduit outlet
74 to draw hot combustion gases from the combustion chamber through the flue
passageway and direct them through the heat exchanger and then exhaust them
through conduits 80 to the outdoors.
As shown in phantom line in Figure 2B, a conduit 81 can also be secured
about the fan 66 to direct the warm air extracted from the flue gas into a
remote
location. Often the hot water tanks are installed in garages and the conduit
81 can
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direct their recovered heat in a living space of a building. The conduit 81
can also be
connected to the ducting of a furnace where the fan of the furnace can direct
the warm
air released from the flue gases into the building structure. As also shown in
Figure 2A,
a condensate collecting conduit 82 is connected to a pan (not shown) but
obvious to a
person skilled in the art to collect condensate from the flue gases as they
are cooled by
the air-to-air heat exchanger and directed the condensate to a drain (not
shown).
Referring now to Figures 3A and 3B, the air-to-air heat exchanger
apparatus 65' is constructed slightly differently and has vertically disposed
spaced-apart
inlet and outlet chambers 85 and 86 as better illustrated in Figure 3B and
interconnected by the horizontally disposed plurality of conduits 87 secured
between
the inlet and outlet chambers and extend between opposed vertical side walls
85' and
86' thereof. The flue connecting inlet 88 is secured to the inlet chamber 85.
The flue
connecting outlet 89 is connected to the outlet chamber 86. Accordingly, the
hot flue
gases exit the flue passageway 61 and into the inlet chamber 85 and then pass
through
the conduits 87 into the outlet chamber 86 and out through the flue connecting
outlet
conduit 89 to exhaust outside of the building structure.
As shown in Figure 3A, a fan 90 is secured in an opening 91 formed in a
top wall 92 of the outer casing housing 67' for pulling ambient air 65'
through the
openings 68' formed in the base of the outer casing housing under the stack of
heat
exchange fins 93 secured in a spaced-apart arrangement around the conduits 87
to
extract heat therefrom and release them into the environment by the fan 90.
Heat is
also extracted from the chambers 85 and 86 and all component parts in the air
flow.
Referring now to Figure 4A, there is shown the construction of a further
modular water heater 100 which is comprised of a water tank 57" secured in an
outer
casing 58". Insulation material 101 disposed between the tank and the outer
casing
58".
Cold domestic water under pressure is fed to the bottom of the tank by
inlet conduit 15 which connects to the diptube 16 and releases cold water in
the bottom
portion of the water tank 57". Hot water is extracted from the top portion of
the water
tank by outlet conduit 19 as previously described.
As shown in Figure 4A, an external modular water heater assembly 102
is detachably connected to the top portion of the water tank and outer casing
top wall
103 by a suitable support frame 104 which is connected to the top wall 103 at
a bottom
end thereof by support legs 105 for disconnect from the top wall 103 of the
tank. Other
attachments are also contemplated as is obvious to a person skilled in the
art. An outer
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casing housing 67" surrounds the modular water heater assembly to conceal the
components of the assembly therein. There are two pipe couplings, namely a
water
supply coupling 106 and a heated water return coupling 107 connected to the
top wall
of the tank and exiting the top wall 103 of the outer casing for connection to
the
modular water heater. The water supply connecting coupling 106 is secured to a
water
supply conduit 106' which extends to a predetermined location in the water
tank, herein
to a lower region of the water tank to extract cooler water therefrom. The
heated water
connecting coupling 107 is connected to a hot water return conduit 107' which
extends
in a substantially central region of the water tank 57" to return hot water
therein.
The modular water heater assembly 102 has a gas-fired burner 108 of a
type well known in the art for heating a fluid circulated in a heat exchanger
109 for heat
transfer communication with the cooler water circulating in a coil conduit
loop 110
connected across the connectors 106 and 107. A pump 111 circulates the cold
water
from the bottom region of the water tank through the coil conduction loop 110.
The fluid
heated in the gas-fired burner 108 circulates through a further conduit loop
119 wherein
heat from the hot fluid gas is extracted from the loop by a heat sink 112 and
transferred
to the coil conduit loop 110 to heat the cooler water therein. A pump 113
circulates the
fluid within the conduit loop 114 and through the gas-fired burner 108. Heat
from the
gas-fired burner 108 is evacuated to the outdoors by an exhaust flue 115. The
heat
sink as hereinshown is formed by a stack of metal conducting fins 112' but the
coupling
means may be done by other heat transfer means such as shown in Figures 4B and
4C
where a concentric arrangement of part of the conduit loops 110 and 114
wherein the
conduit loop 114 has a larger diameter than the conduit loop 110 as shown in
Figure 4B
whereby heat from the conduit 115 is surrounded by the cooler water pumped
from the
water supply conduit 106' whereby a large volume of water surrounds the
conduit 115
containing the hot fluid therein to extract heat.
The external modular water heater 102 is a low pressure modulating gas
power burner. A controller device 116 is connected to a temperature probe 117
to
monitor the temperature of the water in the tank and operates the gas power
burner to
maintain a desired hot water temperature setting. The high efficiency design
of the
heat exchanger (90% +) allows combustion gases to condensate and this
condensate
is evacuated from the heat exchanger through a drain line not shown in Figure
4A, but
obvious to a person skilled in the art. The input modulation is accomplished
using a
variable speed premix combustion blower 120, a venturi (not shown) and a gas
valve
119. The heat transfer fluid from the gas-fired burner could be a mixture of
glycol and
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water or any other type of heat transfer fluid. It is also pointed out that
the water supply
conduit 106' may be an exterior conduit such as shown in phantom lines at 106"
which
is secured to the bottom region of the tank.
Broadly stated, the water heater combo as shown and described in
Figure 4A comprise essentially a water tank 57" for the containment of heated
water
and an external modular water heater 108 detachably connected to the tank to
heat
water therein. As herein described, the modular water heater has a gas-fired
burner for
heating a heat transfer fluid circulated therein in a closed conduit loop 114.
The closed
conduit loop has a portion thereof connected in a heat exchanger arrangement
with a
conduit loop circulating cold water from the bottom region of the tank and
returning it to
a mid-region of the tank after extracting heat from the conduit loop 114.
Therefore, if
there is a need to change the tank after its useful life, it is simply
disconnected from the
gas-fired burner assembly and a new tank reconnected by disconnecting four
pipe
couplings and support feet of a support frame for the burner assembly.
Suitably, the
gas-fired burner can be disconnected for service or replacement.
It is within the ambit of the present invention to cover any obvious
modifications of the water heater device integrated modular designs as
illustrated and
described herein. For example, although the modular heat exchanger or heater
assembly is hereinshown resting on the top wall of the hot water heater by
disconnectable supports 13, it is also foreseen for certain of the embodiments
disclosed
herein that the modular heat exchanger or heater assembly can be suspended
from a
ceiling or attached to an adjoining wall adjacent the water tank or water
heater 10.
Also, all of the conduits may be flexible conduits as now commonly utilized in
plumbing
and provided with appropriate quick disconnect connectors to connect to the
hot water
heater 10. Although the hot water heater 10 of Figure 1 is shown with two
resistive
elements, a third or more resistive elements could be incorporated inside the
inner
casing depending on the performance required for the supply of hot water. The
hot
water device may be constructed for commercial applications and wherein the
hot water
reservoir may be of a larger capacity than domestic water heaters.
