U.S. patent application number 12/812094 was filed with the patent office on 2011-12-15 for water heating system and a method of operating same.
Invention is credited to Patrick Pussell.
Application Number | 20110305444 12/812094 |
Document ID | / |
Family ID | 42242232 |
Filed Date | 2011-12-15 |
United States Patent
Application |
20110305444 |
Kind Code |
A1 |
Pussell; Patrick |
December 15, 2011 |
WATER HEATING SYSTEM AND A METHOD OF OPERATING SAME
Abstract
A hot water system (10) comprising a water storage tank (14) and
an instantaneous-type water heater (12). The water storage tank
(14) has an inlet (22) and outlet (24). The instantaneous-type
water heater (12) has an inlet (18), in fluid communication with a
mains water supply (26), and an outlet (20), in fluid communication
with the inlet (22) of the tank (14). The water heater (12)
energises in response to a flow of water through the water heater
(12).
Inventors: |
Pussell; Patrick; (New South
Wales, AU) |
Family ID: |
42242232 |
Appl. No.: |
12/812094 |
Filed: |
November 3, 2009 |
PCT Filed: |
November 3, 2009 |
PCT NO: |
PCT/AU2009/001432 |
371 Date: |
June 21, 2011 |
Current U.S.
Class: |
392/308 ;
392/465; 392/471 |
Current CPC
Class: |
F24H 9/2028 20130101;
F24D 2220/042 20130101; F24D 2240/26 20130101; F24H 1/122 20130101;
F24D 19/1051 20130101; F24D 17/0031 20130101; F24H 9/2021
20130101 |
Class at
Publication: |
392/308 ;
392/465; 392/471 |
International
Class: |
F24H 1/10 20060101
F24H001/10 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 9, 2008 |
AU |
2008906352 |
Claims
1-21. (canceled)
22. A hot water system comprising: a water storage tank having an
inlet and outlet; and an instantaneous-type water heater having an
inlet, in fluid communication with a mains water supply, and an
outlet, in fluid communication with the inlet of the tank, the
water heater being adapted to energise in response to a flow of
water through the water heater; and a diverter valve having: an
inlet in fluid communication with the mains water supply; a first
outlet in fluid communication with the inlet of the water heater;
and a second outlet in fluid communication with the inlet of the
tank; and a controller adapted to: receive signals indicative of
the temperature of the water in the tank; and issue control signals
to the valve, wherein, when the valve is actuated, the controller
is adapted to control the diverter valve to direct water to the
first outlet in response in response to the temperature signal
indicating that the temperature of the water in the tank is
substantially equal to or below a predetermined value, and to
direct water to the second outlet in response to the temperature
signal indicating that the temperature of the water in the tank is
substantially equal to or above the predetermined value.
23. The hot water system as claimed in claim 22, wherein the first
predetermined temperature value is about 55 Degrees C.
24. The hot water system as claimed in claim 22, wherein the second
predetermined temperature value is preferably about 75 Degrees
C.
25. The hot water system as claimed in claim 22, wherein the hot
water system includes a first temperature sensor at or near the top
of the tank and a second temperature at or neat the bottom of the
tank and, when the valve is actuated, the controller is adapted to
control the diverter valve to direct water to the first outlet in
response in response to the second temperature sensor indicating a
temperature substantially equal to or below a predetermined value,
and to direct water to the second outlet in response to the first
temperature sensor indicating a temperature substantially equal to
or above the predetermined value.
26. The hot water system as claimed in claim 25, wherein the
controller is also adapted to issue control signals to the water
heater which vary the amount of energy applied to the water therein
and thus the temperature of the water leaving the water heater.
27. A method of operating a hot water system, the method
comprising: supplying mains water to an inlet of an
instantaneous-type water heater or an inlet of a water storage
tank; directing the water from an outlet of the tank to a user
controlled outlet; monitoring the temperature of the water in the
tank; and directing the mains water to the inlet of the
instantaneous-type water heater in response in response to the
temperature of the water in the tank being substantially equal to
or below a predetermined value, and directing the mains water to
the inlet of the water storage tank in response to the temperature
of the water in the tank being substantially equal to or above the
predetermined value.
28. A hot water system comprising: a water storage tank having an
inlet and outlet; an instantaneous-type water heater having an
inlet, in fluid communication with a mains water supply, and an
outlet, in fluid communication with the inlet of the tank, the
water heater being adapted to energise in response to a flow of
water through the water heater; and a first pump having an inlet,
in fluid communication with an additional outlet of the tank, and
an outlet, in fluid communication with the inlet of the water
heater; and a controller adapted, upon user instruction, to
energise the pump and cause water to direct water from the outlet
of the water heater to the inlet of the tank and from the second
outlet of the tank to the inlet of the water heater, in order to
heat the water in the tank.
29. The hot water system as claimed in claim 28, wherein the
controller is adapted to vary the speed of the pump, so as to vary
the dwell time of the water passing through the heater and thus the
temperature of the water at the outlet of the heater.
30. The hot water system as claimed in claim 28, wherein the
additional outlet of the tank is at or near the top of the tank and
the second inlet of the tank is at or near the bottom of the
tank.
31. The hot water system as claimed in claim 28, wherein the
additional outlet of the tank is at near the top of the tank and
the tank inlet is at or near the middle of the tank.
32. A method of operating a hot water system, the method
comprising: energising a pump to direct water from into the inlet
of an instantaneous-type water heater; energising the
instantaneous-type water heater in response to water flow
therethrough; directing the heated water from the outlet of the
instantaneous-type water heater to the inlet of a water storage
tank; and directing the water from an outlet of the tank to the
inlet of the instantaneous-type water heater, whereby the water in
the tank can, upon user instruction, be circulated through the
instantaneous-type water heater to heat the water in the tank.
33. The method as claimed in claim 32, wherein the method also
comprises varying the speed of the pump, so as to vary the dwell
time of the water passing through the heater and thus the
temperature of the heated water at the outlet of the heater.
34. A hot water system comprising: a water storage tank having
first and second inlets and first, second and third outlets; an
instantaneous-type water heater having an inlet, in fluid
communication with the first outlet of the tank, and an outlet, the
water heater being adapted to energise in response to a flow of
water through the water heater; a first pump having an inlet, in
fluid communication with the outlet of the water heater, and an
outlet, in fluid communication with the first inlet of the tank; a
second pump having an inlet, in fluid communication with the mains
water supply and the second outlet of the tank, and an outlet; at
least one solar panel having an inlet, in fluid communication with
the outlet of the second pump, and an inlet, in fluid communication
the second inlet of the tank; and a controller selectively adapted
to energise the first and/or the second pump and cause water to
circulate between the water heater and the tank and/or between the
at least one solar panel and the tank respectively.
35. The hot water system as claimed in claim 34, wherein the first
outlet of the tank is at or near the top of the tank.
36. The hot water system as claimed in claim 34, wherein the second
outlet of the tank is at or near the bottom of the tank.
37. The hot water system as claimed in claim 34, wherein the third
outlet of the tank is at or near the top of the tank.
38. The hot water system as claimed in claim 34, wherein the first
inlet of the tank is at or near the middle of the tank.
39. The hot water system as claimed in claim 34, wherein the second
inlet of the tank is at or near the middle of the tank.
40. A method of operating a hot water system, the method
comprising: energising a first pump to direct water from into the
inlet of an instantaneous-type water heater; energising the
instantaneous-type water heater in response to water flow
therethrough; directing the heated water from the outlet of the
instantaneous-type water heater to the inlet of a water storage
tank; directing the water from an outlet of the tank to the inlet
of the instantaneous-type water heater; energising a second pump to
direct water into the inlet of at least one solar panel; directing
the heated water from an outlet of the at least one solar panel to
an inlet of a water storage tank; directing the water from an
outlet of the tank to the inlet of the at least one solar panel,
whereby the water in the tank can be circulated through the
instantaneous-type water heater and/or the at least one solar panel
to heat the water in the tank when required.
41. A hot water system comprising: a water storage tank having
first and second inlets and first and second outlets; an
instantaneous-type water heater having an inlet and an outlet, in
fluid communication with the first inlet of the tank, the water
heater being adapted to energise in response to a flow of water
through the water heater; a pump having an inlet, in fluid
communication with the first outlet of the tank and with a mains
water supply, and an outlet; a diverter valve having: an inlet in
fluid communication with the outlet of the pump; a first outlet in
fluid communication with the inlet of the water heater; and a
second outlet; at least one solar panel having an inlet, in fluid
communication with the second outlet of the diverter valve, and an
outlet, in fluid communication the second inlet of the tank; and a
controller adapted to selectively energise the second pump and to
control the diverter valve to direct water to the first outlet to
circulate water between the water heater and the tank or to direct
water to the second outlet to circulate water between the at least
one solar panel and the tank.
42. The hot water system as claimed in claim 41, wherein the
diverter valve includes a third outlet in fluid communication with
atmosphere.
43. The hot water system as claimed in claim 41, wherein the first
outlet of the tank is at or near the top of the tank.
44. The hot water system as claimed in claim 41, wherein the second
outlet of the tank is at or near the bottom of the tank.
45. The hot water system as claimed in claim 41, wherein the first
inlet of the tank is at or near the top of the tank.
46. The hot water system as claimed in claim 41, wherein the second
inlet of the tank is at or near the middle of the tank.
47. A method of operating a hot water system, the method
comprising: energising a pump; directing water from an outlet of
the pump into: (1) an inlet of an instantaneous-type water heater;
energising the instantaneous-type water heater in response to a
flow of water through the heater; directing the heated water from
the outlet of the instantaneous-type water heater to the inlet of a
water storage tank; and/or (2) directing the water from the outlet
of the pump to an inlet at least one solar panel; directing the
heated water from an outlet of the at least one solar panel to an
inlet of a water storage tank; and directing the water from an
outlet of the tank to the inlet of the at least one solar panel,
whereby the water in the tank can be circulated through the
instantaneous-type water heater and/or the at least one solar panel
to heat the water in the tank when required.
48. The hot water system as claimed in claim 5, wherein the system
includes at least one water tank temperature sensor in signal
communication with the controller.
49. The hot water system as claimed in claim 48, wherein the system
includes a first water tank temperature sensor near the top of the
tank and a second water tank temperature sensor near the bottom of
the tank.
50. The hot water system as claimed in claim 49, wherein the system
also includes a third water tank temperature sensor near the middle
of the tank.
51. The hot water system as claimed in claim 49, wherein the
controller is adapted to determine a temperature gradient across
the height of the tank using at least two of the first, second and
third temperature sensors.
52. The hot water system as claimed in claim 49, wherein the
controller is adapted to determine a temperature gradient across
the height of the tank using all of the first, second and third
temperature sensors.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a water heating system and
a method of operating same.
[0002] The present invention has been primarily developed for use
with gas instantaneous type water heaters and will be described
hereinafter with reference to that application. However, the
invention is not limited in this particular field of use and can
also be used with electrical instantaneous-type heaters. In the
United States of America, instantaneous-type water heaters are
known as tank-less heaters.
BACKGROUND OF THE INVENTION
[0003] Known instantaneous type heaters have an inlet, connected to
a mains water supply, and an outlet connected to, for example, a
tap. The flow of water through the heater automatically energises
the gas burners or electrical elements therein. This known
arrangement has two disadvantages.
[0004] The first disadvantage relates to water wastage. When a user
activates a hot water tap, the user must wait for the mains
supplied water to be heated, and for all the unheated water in the
pipes between the heater outlet and the tap to be purged, before
receiving the heated water at the tap. The Australian Federal
Government departments concerned with water conservation estimate
that usage of this type in an average household occurs about 19
times a day and wastes up to 90 litres of water a day.
[0005] The second disadvantage relates to two types of gas wastage.
The first type of gas wastage occurs because, as mentioned above,
known instantaneous type heaters ignite their burners upon sensing
flow of water through the heater, caused by opening a hot water
tap. In the case of a shower, the heater takes some time to come up
to temperature and the cool-to-warm water delivered in the
intervening heating period is often dumped to waste by the
householder. The second type of gas wastage occurs because many
users only turn on the hot tap when washing their hands, wash in
the initial cold-to-lukewarm water, and then simply turn off the
tap. In that situation, gas is used to solely go through a start up
phase and heated water is left in the pipes, which then cools and
is thus wasted.
[0006] It is an object of the present invention to reduce water and
gas wastage in water heating systems utilizing an
instantaneous-type water heater.
SUMMARY OF THE INVENTION
[0007] Accordingly, in a first aspect, the present invention
provides a hot water system comprising:
[0008] a water storage tank having an inlet and outlet; and
[0009] an instantaneous-type-water heater having an inlet, in fluid
communication with a mains water supply, and an outlet, in fluid
communication with the inlet of the tank,
[0010] wherein the water heater energises in response to a flow of
water through the water heater.
[0011] The tank is preferably insulated.
[0012] The tank outlet is preferably in fluid communication with a
user controlled valve, such as a tap.
[0013] In a second aspect, the present invention provides method of
operating a hot water system, the method comprising:
[0014] supplying mains water to an inlet of an instantaneous-type
water heater;
[0015] energising the instantaneous-type water heater in response
to the water being supplied thereto;
[0016] directing the heated water from an outlet of the
instantaneous-type water heater to an inlet of a water storage
tank; and
[0017] directing the heated water from an outlet of the tank to a
user controlled outlet.
[0018] In a third aspect, the present invention provides a hot
water system comprising:
[0019] a water storage tank having an inlet and outlet;
[0020] an instantaneous-type water heater having an inlet, in fluid
communication with a mains water supply, and an outlet, in fluid
communication with the inlet of the tank; and
[0021] a controller adapted to: receive a signal indicative of the
temperature of the water in the tank; and issue a control signal to
the water heater,
[0022] wherein the controller is adapted to energise the water
heater in response to the temperature signal indicating that the
temperature of the water in the tank is substantially equal to or
below a first predetermined value.
[0023] The controller is preferably also adapted to not energise,
or de-energise, the water heater in response to the temperature
signal indicating that the temperature of the water in the tank is
substantially equal to or above a second predetermined value.
[0024] The controller is preferably also adapted to not energise,
or de-energise, the water heater in response to the temperature
signal indicating that the temperature of the water in the tank is
substantially equal to or above the first predetermined value and
substantially equal to or below the second predetermined value.
[0025] The controller is preferably also adapted to issue control
signals to the water heater which vary the amount of energy applied
to the water therein and thus the temperature of the water leaving
the water heater.
[0026] The first predetermined temperature value is preferably
about 55 Degrees C. The second predetermined temperature value is
preferably about 75 Degrees C.
[0027] In one form, the hot water system includes a first
temperature sensor at or near the middle of the tank.
[0028] In another form, the hot water system includes a first
temperature sensor at or near the top of the tank and a second
temperature sensor at or near the bottom of the tank and the
controller is adapted to energise the water heater in response to
the second temperature sensor indicating a temperature
substantially equal to or below the first predetermined value. The
controller is preferably also adapted to not energise, or
de-energise, the water heater in response to the first temperature
sensor indicating a temperature substantially equal to or above the
second predetermined value. The controller is preferably also
adapted to not energise, or de-energise, the water heater in
response to the second temperature sensor indicating a temperature
substantially equal to or above the first predetermined value and
the first temperature sensor indicating a temperature substantially
equal to or below the second predetermined value.
[0029] The controller is preferably also adapted to issue control
signals to the water heater which vary the amount of energy applied
to the water therein and thus the temperature of the water leaving
the water heater.
[0030] In a fourth aspect, the present invention provides a method
of operating a hot water system, the method comprising:
[0031] supplying mains water to an inlet of an instantaneous-type
water heater;
[0032] directing the water from an outlet of the instantaneous-type
water heater to an inlet of a water storage tank;
[0033] directing the water from an outlet of the tank to a user
controlled outlet;
[0034] monitoring the temperature of the water in the tank; and
[0035] energising the instantaneous-type water heater in response
heater in response to the temperature signal indicating that the
temperature of the water in the tank is substantially equal to or
below a first predetermined value.
[0036] The method preferably includes not energising, or
de-energising, the water heater in response to the temperature
signal indicating that the temperature of the water in the tank is
substantially equal to or above a second predetermined value.
[0037] The method preferably includes not energising, or
de-energising, the water heater in response to the temperature
signal indicating that the temperature of the water in the tank is
substantially equal to or above the first predetermined value and
substantially equal to or below the second predetermined value.
[0038] The first predetermined temperature value is preferably
about 55 Degrees C. The second predetermined temperature value is
preferably about 75 Degrees C.
[0039] The method preferably also comprises varying the amount of
energy applied to the water by the instantaneous-type water heater
to vary the temperature of the water leaving the water heater.
[0040] In a fifth aspect, the present invention provides a hot
water system comprising:
[0041] a water storage tank having an inlet and outlet;
[0042] an instantaneous-type water heater having an inlet, in fluid
communication with a mains water supply, and an outlet, in fluid
communication with the inlet of the tank, the water heater being
adapted to energise in response to a flow of water through the
water heater; and
[0043] a diverter valve having:
[0044] an inlet in fluid communication with the mains water supply;
a first outlet in fluid communication with the inlet of the water
heater; and a second outlet in fluid communication with the inlet
of the tank; and
[0045] a controller adapted to: receive signals indicative of the
temperature of the water in the tank; and issue control signals to
the valve,
[0046] wherein, when the valve is actuated, the controller is
adapted to control the diverter valve to direct water to the first
outlet in response in response to the temperature signal indicating
that the temperature of the water in the tank is substantially
equal to or below a predetermined value, and to direct water to the
second outlet in response to the temperature signal indicating that
the temperature of the water in the tank is substantially equal to
or above the predetermined value.
[0047] The first predetermined temperature value is preferably
about 55 Degrees C. The second predetermined temperature value is
preferably about 75 Degrees C.
[0048] In one form, the hot water system includes a first
temperature sensor at or near the top of the tank and a second
temperature at or neat the bottom of the tank and, when the valve
is actuated, the controller is adapted to control the diverter
valve to direct water to the first outlet in response in response
to the second temperature sensor indicating a temperature
substantially equal to or below a predetermined value, and to
direct water to the second outlet in response to the first
temperature sensor indicating a temperature substantially equal to
or above the predetermined value.
[0049] The controller is preferably also adapted to issue control
signals to the water heater which vary the amount of energy applied
to the water therein and thus the temperature of the water leaving
the water heater.
[0050] In a sixth aspect, the present invention provides a method
of operating a hot water system, the method comprising:
[0051] supplying mains water to an inlet of an instantaneous-type
water heater or an inlet of a water storage tank;
[0052] directing the water from an outlet of the tank to a user
controlled outlet;
[0053] monitoring the temperature of the water in the tank; and
[0054] directing the mains water to the inlet of the
instantaneous-type water heater in response in response to the
temperature of the water in the tank being substantially equal to
or below a predetermined value, and directing the mains water to
the inlet of the water storage tank in response to the temperature
of the water in the tank being substantially equal to or above the
predetermined value.
[0055] In a seventh aspect, the present invention provides a hot
water system comprising:
[0056] a water storage tank having an inlet and outlet; and
[0057] an instantaneous-type water heater having an inlet, in fluid
communication with a mains water supply, and an outlet, in fluid
communication with the inlet of the tank, the water heater being
adapted to energise in response to a flow of water through the
water heater; and
[0058] a first pump having an inlet, in fluid communication with an
additional outlet of the tank, and an outlet, in fluid
communication with the inlet of the water heater; and
[0059] a controller adapted, upon user instruction, to energise the
pump and cause water to direct water from the outlet of the water
heater to the inlet of the tank and from the second outlet of the
tank to the inlet of the water heater, in order to heat the water
in the tank.
[0060] Preferably, the controller is adapted to vary the speed of
the pump, so as to vary the dwell time of the water passing through
the heater and thus the temperature of the water at the outlet of
the heater.
[0061] The additional outlet of the tank is preferably at or near
the top of the tank and the second inlet of the tank is preferably
at or near the bottom of the tank.
[0062] In a variation of this embodiment, the additional outlet of
the tank is at near the top of the tank and the tank inlet is at or
near the middle of the tank.
[0063] In an eight aspect, the present invention provides a method
of operating a hot water system, the method comprising:
[0064] energising a pump to direct water from into the inlet of an
instantaneous-type water heater;
[0065] energising the instantaneous-type water heater in response
to water flow therethrough;
[0066] directing the heated water from the outlet of the
instantaneous-type water heater to the inlet of a water storage
tank; and
[0067] directing the water from an outlet of the tank to the inlet
of the instantaneous-type water heater,
[0068] whereby the water in the tank can, upon user instruction, be
circulated through the instantaneous-type water heater to heat the
water in the tank.
[0069] The method preferably also comprises varying the speed of
the pump, so as to vary the dwell time of the water passing through
the heater and thus the temperature of the heated water at the
outlet of the heater.
[0070] In a ninth aspect, the present invention provides a hot
water system comprising:
[0071] a water storage tank having first and second inlets and
first, second and third outlets;
[0072] an instantaneous-type water heater having an inlet, in fluid
communication with the first outlet of the tank, and an outlet, the
water heater being adapted to energise in response to a flow of
water through the water heater;
[0073] a first pump having an inlet, in fluid communication with
the outlet of the water heater, and an outlet, in fluid
communication with the first inlet of the tank;
[0074] a second pump having an inlet, in fluid communication with
the mains water supply and the second outlet of the tank, and an
outlet;
[0075] at least one solar panel having an inlet, in fluid
communication with the outlet of the second pump, and an inlet, in
fluid communication the second inlet of the tank; and
[0076] a controller selectively adapted to energise the first
and/or the second pump and cause water to circulate between the
water heater and the tank and/or between the at least one solar
panel and the tank respectively.
[0077] The first outlet of the tank is preferably at or near the
top of the tank. The second outlet of the tank is preferably at or
near the bottom of the tank. The third outlet of the tank is
preferably at or near the top of the tank. The first inlet of the
tank is preferably at or near the middle of the tank. The second
inlet of the tank is preferably at or near the middle of the
tank.
[0078] In a tenth aspect, the present invention provides a method
of operating a hot water system, the method comprising:
[0079] energising a first pump to direct water from into the inlet
of an instantaneous-type water heater;
[0080] energising the instantaneous-type water heater in response
to water flow therethrough;
[0081] directing the heated water from the outlet of the
instantaneous-type water heater to the inlet of a water storage
tank;
[0082] directing the water from an outlet of the tank to the inlet
of the instantaneous-type water heater;
[0083] energising a second pump to direct water into the inlet of
at least one solar panel;
[0084] directing the heated water from an outlet of the at least
one solar panel to an inlet of a water storage tank; and
[0085] directing the water from an outlet of the tank to the inlet
of the at least one solar panel,
[0086] whereby the water in the tank can be circulated through the
instantaneous-type water heater and/or the at least one solar panel
to heat the water in the tank when required.
[0087] In an eleventh aspect, the present invention provides a hot
water system comprising:
[0088] a water storage tank having first and second inlets and
first and second outlets;
[0089] an instantaneous-type water heater having an inlet and an
outlet, in fluid communication with the first inlet of the tank,
the water heater being adapted to energise in response to a flow of
water through the water heater;
[0090] a pump having an inlet, in fluid communication with the
first outlet of the tank and with a mains water supply, and an
outlet;
[0091] a diverter valve having: an inlet in fluid communication
with the outlet of the pump; a first outlet in fluid communication
with the inlet of the water heater; and a second outlet;
[0092] at least one solar panel having an inlet, in fluid
communication with the second outlet of the diverter valve, and an
outlet, in fluid communication the second inlet of the tank;
and
[0093] a controller adapted to selectively energise the second pump
and to control the diverter valve to direct water to the first
outlet to circulate water between the water heater and the tank or
to direct water to the second outlet to circulate water between the
at least one solar panel and the tank.
[0094] The diverter valve preferably includes a third outlet in
fluid communication with atmosphere.
[0095] The first outlet of the tank is preferably at or near the
top of the tank. The second outlet of the tank is preferably at or
near the bottom of the tank. The first inlet of the tank is
preferably at or near the top of the tank. The second inlet of the
tank is preferably at or near the middle of the tank.
[0096] In a twelfth aspect, the present invention provides a method
of operating a hot water system, the method comprising:
[0097] energising a pump;
[0098] directing water from an outlet of the pump into: [0099] (1)
an inlet of an instantaneous-type water heater; [0100] energising
the instantaneous-type water heater in response to a flow of water
through the heater; [0101] directing the heated water from the
outlet of the instantaneous-type water heater to the inlet of a
water storage tank; and/or [0102] (2) directing the water from the
outlet of the pump to an inlet at least one solar panel; [0103]
directing the heated water from an outlet of the at least one solar
panel to an inlet of a water storage tank; and [0104] directing the
water from an outlet of the tank to the inlet of the at least one
solar panel,
[0105] whereby the water in the tank can be circulated through the
instantaneous-type water heater and/or the at least one solar panel
to heat the water in the tank when required.
[0106] The systems according to the second to twelfth aspects
preferably include at least one water tank temperature sensor in
signal communication with the controller. In one form, the system
includes a first water tank temperature sensor near the top of the
tank and a second water tank temperature sensor near the bottom of
the tank. In another form, the system also includes a third water
tank temperature sensor near the middle of the tank. The controller
is preferably adapted to determine a temperature gradient across
the height of the tank using at least two, more preferably three,
of the first, second and third temperature sensors.
BRIEF DESCRIPTION OF THE DRAWINGS
[0107] Preferred embodiments of the invention will now be
described, by way of examples only, with reference to the
accompanying drawings in which:
[0108] FIG. 1 is a schematic view of a first embodiment of a water
heating system;
[0109] FIG. 2a is a schematic view of a first version of a second
embodiment of a water heating system;
[0110] FIG. 2b is a schematic view of a second version of the
second embodiment of a water heating system;
[0111] FIG. 3 is a schematic view of a third embodiment of a water
heating system;
[0112] FIG. 4 is a schematic view of a fourth embodiment of a water
heating system;
[0113] FIG. 5 is a schematic view of a fifth embodiment of a water
heating system;
[0114] FIG. 6 is a schematic view of a sixth embodiment of a water
heating system; and
[0115] FIG. 7 is a schematic view of a seventh embodiment of a
water heating system.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0116] FIG. 1 shows a first embodiment of a water heating system 10
comprising a gas instantaneous-type water heater 12, preferably of
4, 5 or 6-Star rating. The burners in the heater 12 are
automatically energised upon sensing flow of water through the
heater 12. The system 10 also includes a (buffer) water storage
tank 14, preferably 4-50 litres in volume. The tank 14 is encased
in insulation 16. The heater 12 has an inlet 18 and an outlet 20.
The tank 14 has an inlet 22 and an outlet 24. The inlet 18 of the
heater 12 is connected to a mains water supply pipe 26. The outlet
of the heater 12 is connected to the inlet 22 of the tank 14 by a
pipe 28. The outlet 24 of the tank 14 is connected to a
user-controlled outlet device, such as a hot tap (not shown), by a
pipe 30.
[0117] When the tap is initially actuated by a user, water flows
from the mains supply pipe 26 into the heater 12 and is heated by
the gas burners therein. The heated water then flows through pipe
28 into the tank 14 and, after the tank 14 is filled, through the
pipe 30 to the user. Thereafter, when the user actuates the hot
water supply, it can be drawn from the volume of heated water
residing in the tank 14. This advantageously means that, whilst the
water in the tank 14 remains sufficiently heated, the user does not
have to wait for cold water to be heated and then supplied to them.
The system 10 thus provides heated water to the user more quickly
than the existing system described previously, thereby reducing the
amount of water that is otherwise wasted whilst the user waits for
heated water to reach the tap. The system 10 also avoids wasting of
the gas used that would have been used whilst the user is waiting.
This effect can be optimized by positioning the tank (or multiple
tanks) near the user-controlled outlets (or outlets). Whilst the
tank 14 does not require the insulation 16, the insulation 16
improves the retention of the energy supplied to the heated water
in the tank 14. It should also be noted that the flow rate of the
water leaving the tank 14 is limited by the capacity of the heater
12 to pass water under mains pressure.
[0118] A first version 40a of a second embodiment of water heating
system is shown in FIG. 2a. The water heating system 40a is similar
to the water heating system 10 shown in FIG. 1 and like features
have been indicated with like reference numerals. However, the
water heating system 40a also includes a controller 42. The
controller 42 receives signals indicative of water temperature in
the (4-50 litre) tank 14 from a sensor 44 which is positioned near
the middle of the tank 14. The controller 42 is also connected to
the heater 12 and is able to control whether or not the heater 12
is energised in response to water flow. As the heater 12 does not
energise automatically in response to water flow, it can be
simplified and is thus less expensive.
[0119] If the sensor 44 indicates to the controller 42 a water
temperature of about 55 Degrees C. or less, then the controller 42
will energise the heater 12. If the sensor 44 indicates to the
controller 42 a water temperature between about 55 Degrees C. and
about 75 Degrees C., then the controller 42 will not energise the
heater 12 or, if operating, de-energise the heater 12.
[0120] A second version 40b of the second embodiment of water
heating system is shown in FIG. 2b, which is better suited for tank
volumes of 50-400 litres. The water heating system 40b is similar
to the water heating system 40a shown in FIG. 2 and like features
have been indicated with like reference numerals. However, in the
water heating system 40b, the controller receives signals
indicative of water temperature in the tank 14 from first and
second sensors 44a and 44b, which are positioned near the top and
bottom of the tank 14 respectively.
[0121] If the second/bottom sensor 44b indicates to the controller
42 a water temperature of about 55 Degrees C. or less, then the
controller 42 will energise the heater 12. If the first/top sensor
44a indicates to the controller 42 a water temperature of about 75
Degrees C. or more, then the controller 42 will not energise the
heater 12 or, if operating, de-energise the heater 12. If the
second/bottom sensor 44b indicates to the controller 42 a water
temperature of about 55 Degrees C. or more and the first/top sensor
44a indicates to the controller 42 a water temperature of about 75
Degrees C. or less, then the controller 42 will not energise the
heater 12 or, if operating, de-energise the heater 12. The dual
sensors 44a and 44b increase the sensitivity and accuracy of the
control of the water heater 40b.
[0122] The systems 40a and 40b reduce water wastage in the same
manner as was described with reference to the water heating system
10. The systems 40a and 40b also reduces gas wastage as gas is not
supplied to the heater 12 during the conditions described above,
which could otherwise be wasted as previously described.
[0123] FIG. 3 shows a third embodiment of a water heating system
50. The water heating system 50 is similar to the water heating
systems 40a and 40b shown in FIG. 2a and FIG. 2b and like features
have been indicated with like reference numerals. However, in the
water heating system 50, the controller 42 is also connected to a
pump 52. The tank 14 also includes an additional outlet 54 which is
connected to an inlet 56 of the pump 52 by a pipe 58. An outlet 60
of the pump 52 is connected to the mains water supply pipe 26 by a
pipe 62.
[0124] If the second/bottom sensor 44b indicates to the controller
42 a water temperature of about 55 Degrees C. or less, then the
controller 42 will energise the heater 12. If the first/top sensor
44a indicates to the controller 42 a water temperature of about 75
Degrees C. or more, then the controller 42 will not energise the
heater 12 or, if operating, de-energise the heater 12. If the
second/bottom sensor 44b indicates to the controller 42 a water
temperature of about 55 Degrees C. or more and the first/top sensor
44a indicates to the controller 42 a water temperature of about 75
Degrees C. or less, then the controller 42 will not energise the
heater 12 or, if operating, de-energise the heater 12. In addition,
the controller 42 can, in response to a user instruction, energise
the heater 12 and the pump 52 and cause water to circulate between
the tank 14 and the heater 12 in order to pre-heat the volume of
the tank 14. This is a particularly desirable feature for tanks 14
having relatively large storage volumes, such as 50-400 litres.
[0125] In this embodiment, the controller 42 determines if the
water in the tank 14 has cooled, either due to usage or due to heat
loss, and advantageously reacts accordingly. This embodiment also
allows the entire volume of the tank 14 to be pre-heated on demand
(for example, to stabilize water temperature in the tank 14) and
then supplied at mains supply flow rates (for example, to fill a
bath). This is advantageous in many situations as mains supply flow
rates are higher than those of instantaneous-type heaters.
[0126] The speed of the pump 52 is dependant on the desired outlet
temperature of the heater 12. The desired heater outlet temperature
is dependent on the design of the heater 12 and incoming water
temperature. For example, and generally speaking, for a given
outlet temperature of say 70 Degrees C. and incoming mains water
supply of 10 Degrees, the pump speed is set relatively slow to
increase the dwell time of the water and maximize the efficiency of
the heat transfer rates in the heater 12. However, if the incoming
mains water temperature was 30 Degrees C., the speed of the pump 52
would be increased to maximize heat transfer in the heater 12.
Ambient air temperature will also affect pump speed, but to a
lesser degree.
[0127] The controller 42 can also vary the speed of the pump 52 in
order to vary and control the dwell time of the water passing
through the heater 12 and thus its resultant temperature. In
addition, controlling the speed of the pump 52 can be used to
influence the amount of mixing (stratification) and temperature
degradation of the water in the tank 14. For example, generally
speaking, a very high flow rate, such as 12 litres per minute, will
cause the heated water entering the tank 14 to mix with the water
already in the tank 14. However, a relatively slow flow rate, such
as 5 litres per minute, results in the heated water not
substantially mixing with the water already in the tank 14 and
instead forming stratifications or layers within the tank 14. In
these layers, the hottest water in the tank 14 is advantageously
nearest to the outlet 24, and thus the user.
[0128] Controlling the water temperature by simply controlling the
pump speed allows the cost of the water heating system 50 to be
reduced as the relatively expensive control electronics required
to, for example, regulate water heating by varying gas flow, flame
intensity and/or flame size are no longer required. The heater 12
can instead be run at a constant (high efficiency) heat level and
merely be switched on or off.
[0129] A fourth embodiment of a water heating system 70 is shown in
FIG. 4. The water heating system 70 is similar to the water heating
systems 40a and 40b shown in FIG. 2a and FIG. 2b except the
controller 42 is connected to a diverter valve 72. The valve 72
includes an inlet 72a connected to the mains water supply pipe 26,
a first outlet 72b, connected to the inlet 18 of the water heater
12 by pipe 74, and a second outlet 72c, connected to the pipe 28
and thus to the inlet 22 of the pump 14 by a pipe 76. The
controller 42 can control the valve 72 to direct water from the
mains supply pipe 26 from the inlet 72a to either the first outlet
72b or to the second outlet 72c. In this embodiment, the heater 12
automatically energises upon sensing a flow of water
therethrough.
[0130] If the second/bottom sensor 44b indicates to the controller
42 a water temperature of 55 Degrees C. or less, then the
controller 42 will control the valve 72 to divert water from the
main supply 76 to the first outlet 72b and so to the inlet 18 of
the water heater 12. As stated above, the heater 12 automatically
energises upon sensing a flow of water therethrough caused by, for
example, a user opening a hot water tap.
[0131] If the second/bottom sensor 44b indicates to the controller
42 a water temperature of 55 Degrees C. or more and the first/top
sensor 44a indicates to the controller 42 a water temperature of
about 75 Degrees C. or less, then the controller 42 controls the
valve 72 to direct water from the mains supply 26 to the second
outlet 72c and thereby directly to the inlet 22 of the tank 14.
[0132] As with the heater 40, when the controller 42 senses that
the water in the tank 14 is sufficiently heated, it controls the
valve 72 to direct water from the mains supply 26 to the second
outlet 72c and thereby to the inlet 22 of the tank 14. As a result,
these water volumes do not pass through the water heater 12 which
is therefore not energised and gas usage is reduced.
[0133] Water usage is also reduced in the same manner as was
described in relation to the water heating systems 40a and 40b.
[0134] In addition to the gas and water savings previously
described, the water heater 70 also has the additional advantage
that a very simple and inexpensive heater 12 can be utilized,
without control components, as it simply automatically energises
and operates at full capacity upon sensing a flow of water
therethrough.
[0135] A fifth embodiment of a water heating system 80 is shown in
FIG. 5. The water heating system 80 has components in common with
the water heating system shown in earlier embodiments and like
features have again been indicated with like reference numerals.
The water heating system 80 has a gas (instantaneous-type) water
heating circuit, indicated generally by the reference numeral 82,
and a solar water heating circuit, indicated generally by the
reference numeral 84. The gas circuit 82 includes a pump 84 having
an inlet 86, connected to the outlet 20 of the water heater 12 by
pipe 88, and an outlet 90, connected to an inlet 92 at about the
middle of the tank 14. The tank 14 also includes an additional
outlet 94 connected to the inlet 18 of the heater 12 by pipe 96.
The solar circuit 84 includes a solar panel 98 and a pump 100. The
outlet 102 of the pump 100 is connected to an inlet 104 of the
solar panel 98 by a pipe 106. The solar panel 98 also has an outlet
108 connected to an additional inlet 110 of the tank 14 by pipe
112. The pump 100 also has an inlet 114 connected to an outlet 116
by pipe 118. The mains water supply pipe 26 is Tee'd into the pipe
118. The system 80 also includes a third temperature sensor 44c
near the middle of the tank 14 and a fourth temperature sensor 44d
at the outlet of the solar panel 98. Both of the sensors 44c and
44d are connected to the controller 42.
[0136] When the controller energises the first pump 84, water is
circulated between the upper portion of the tank 14 and the water
heater 12 in order to pre-heat same. When the controller 42
energises the second pump 100, and sufficient solar energy is
available, water is circulated between the bottom portion of the
tank 14 and the solar panel 98 in order to pre-heat same.
[0137] Generally speaking, the controller 42 determines when one or
both of the pumps 84 and 100 are activated in order to best suit
different expected demands. The controller 42 will always to
attempt to heat the water using solar energy over gas energy. More
particularly, if the temperature at the sensor 44d is more than
about 4 Degrees C. than the temperature at the sensor 44c, then the
controller 42 will energise the second pump 100 (of the solar
circuit 84). The controller 42 will keep the second pump 102
energised unless there is less than about a 4 Degree C. difference
between the sensor 44d and the sensor 44b or if the sensor 44a
indicates a water temperature of 80 Degrees C. or more. A
temperature of 80 Degrees C. is acceptable in the lower part of the
tank 14 as the heat will redistribute into the upper half of the
tank if hot water is not being used.
[0138] If the third/middle sensor 44c indicates to the controller
42 a water temperature of 55 Degrees C. or less, then the
controller 42 will energise the pump 90 (of the gas circuit 82).
The controller 42 will de-energise the pump 90 if the first/top
sensor 44a indicates a water temperature of about 75 Degrees C. or
more. If the third/middle sensor 44c indicates to the controller 42
a water temperature of 55 Degrees C. or more and the first/top
sensor 44a indicates a water temperature of about 75 Degrees C. or
less, then the controller will not energise, or de-energise, the
pump 90.
[0139] If the sensor 44a indicates a water temperature of about 80
Degrees C. or more, then both the first pump 90 and the second pump
102 are de-energised, to prevent over-heating.
[0140] In addition, the controller 42 can, in response to a user
instruction, energise the heater 12 and the pump 90 and cause water
to circulate between the tank 14 and the heater 12 in order to
pre-heat or stabilize the volume of the tank 14. This is a
particularly desirable feature for tanks 14 having relatively large
storage volumes, such as 50-400 litres.
[0141] A sixth embodiment of a water heating system 120 is shown in
FIG. 6. The water heating system 120 is similar to the water
heating system 80 shown in FIG. 5 and like components are indicated
with like reference numerals. However, the water heating system 120
includes only a single pump 122 and a diverter valve 124 which has
an inlet 126, a first outlet 128 and a second outlet 130.
[0142] When the controller 42 determines that water should be
circulated through the gas circuit 82, the pump 122 is energized
and the diverter valve 124 is controlled to divert water from the
inlet 126 to the first outlet 128 and so to the inlet 18 of the
water heater 12 by pipe 132. The heated water leaves the outlet 20
of the heater 12 and is supplied to an inlet 134 of the tank 14 by
pipe 136. Water is drawn from an outlet 138 of the tank through
pipe 140 into an inlet 142 of the pump 122. The pump also has an
outlet 144 connected to the inlet 126 of the diverter valve 124 by
pipe 146.
[0143] When the controller 42 determines that water should be
circulated through the solar circuit 84, the pump 122 is energized
and the diverter valve 124 is controlled to divert water from the
inlet 126 to the second outlet 130. The second outlet 130 is
connected to the inlet 104 of the solar panel 98 by pipe 148. The
outlet 108 of the solar panel 98 is connected to an inlet 150 of
the tank 14 by pipe 152.
[0144] The controller 42 will always to attempt to heat the water
using solar energy over gas energy. More particularly, if the
temperature at the sensor 44d is more than about 4 Degrees C. than
the temperature at the sensor 44c, then the controller 42 will
divert water through the solar circuit 84. The controller 42 will
keep water flowing through the solar circuit 84 unless there is
less that about a 4 Degree C. difference between the sensor 44d and
the sensor 44b or if the sensor 44a indicates a water temperature
of 85 Degrees C. or more. A temperature of 85 Degrees C. is
acceptable in the lower part of the tank 14 as the heat will
redistribute into the upper half of the tank if hot water is not
being used.
[0145] If the third/middle sensor 44c indicates to the controller
42 a water temperature of 55 Degrees C or less, then the controller
42 will divert water through the gas circuit. The controller 42
will de-energise the pump 122 if the first/top sensor 44a indicates
a water temperature of about 75 Degrees C. or more. If the
third/middle sensor 44c indicates to the controller 42 a water
temperature of 55 Degrees C. or more and the first/top sensor 44a
indicates a water temperature of about 75 Degrees C. or less, then
the controller will divert water through the solar circuit 84.
[0146] In addition, the controller 42 can, in response to a user
instruction, energise the heater 12 and the pump 122 and cause
water to circulate between the tank 14 and the heater 12 in order
to pre-heat or stabilize the volume of the tank 14. This is a
particularly desirable feature for tanks 14 having relatively large
storage volumes, such as 50-400 litres. It can also be desirable,
because of regulations, to sterilise the tank 14 from time to time
(e.g. for legionella control). For some authorities, this can be
performed using the gas circuit 82 until the top and middle sensors
44a and 44c indicate 60 degrees C. or more. Alternatively, for
other authorities, this can be performed using the gas circuit 82
until the top and bottom sensors 44a and 44b (ie. the whole of the
tank 14) indicate 60 degrees C.
[0147] FIG. 7 shows a seventh embodiment of a water heating system
160. The system 160 is similar to the system 120 shown in FIG. 6
and like components have been indicated with like reference
numerals. However, in the system 160, the diverter valve 124 also
has a third outlet 162 which is connected to a pipe 164 which can
drain to atmosphere, or for collection for re-use. If the
controller 42 determines that the ambient temperature is cold
enough to freeze water in the solar panel 98 and damage same, then
the diverter valve 124 is controlled to direct water from the inlet
126 to the third outlet 162. This causes the water in the solar
panel 98 to empty through pipe 164. Draining can also be performed
to prevent over-heating of the solar panel 98. These draining
operations are described in the Applicant's International PCT
Patent Application No. PCT/AU2008/001476 filed 3 Oct. 2008, the
relevant contents of which are incorporated herein by cross
reference.
[0148] Although the invention has been described with reference to
specific examples, it will be appreciated by a person skilled in
the art that the invention can be embodied in many other forms. For
example, the gas instantaneous water heaters can be replaced with
electric instantaneous water heaters which results in electrical
energy being saved instead of gas being saved.
* * * * *