U.S. patent application number 14/892607 was filed with the patent office on 2016-06-16 for fluid temperature modification apparatus.
This patent application is currently assigned to UNIVERSITY OF WAIKATO. The applicant listed for this patent is UNIVERSITY OF WAIKATO. Invention is credited to Alythwela Domingo Vithanage Nihal KULARATNA.
Application Number | 20160169557 14/892607 |
Document ID | / |
Family ID | 51933838 |
Filed Date | 2016-06-16 |
United States Patent
Application |
20160169557 |
Kind Code |
A1 |
KULARATNA; Alythwela Domingo
Vithanage Nihal |
June 16, 2016 |
FLUID TEMPERATURE MODIFICATION APPARATUS
Abstract
In one aspect the invention provides a fluid temperature
modification apparatus which includes at least one temperature
modification element s associated with a fluid conduit. This
temperature modification element or elements are located adjacent
to an outlet of the fluid conduit. The apparatus also includes at
least one energy storage capacitor, and at least one trigger switch
which when operated connects one or more energy storage capacitors
to a temperature modification element. The operation of a trigger
switch at least partially discharges at least one energy storage
capacitor to energise a temperature modification element which
modifies the temperature of fluid in the conduit adjacent to the
outlet port of the conduit.
Inventors: |
KULARATNA; Alythwela Domingo
Vithanage Nihal; (Hamilton, NZ) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
UNIVERSITY OF WAIKATO |
Hamilton |
|
NZ |
|
|
Assignee: |
UNIVERSITY OF WAIKATO
Hamilton
NZ
|
Family ID: |
51933838 |
Appl. No.: |
14/892607 |
Filed: |
May 21, 2014 |
PCT Filed: |
May 21, 2014 |
PCT NO: |
PCT/NZ2014/000092 |
371 Date: |
November 20, 2015 |
Current U.S.
Class: |
392/486 ;
219/491 |
Current CPC
Class: |
F24H 1/102 20130101;
F24H 1/103 20130101; F24D 19/1051 20130101; F24D 2200/08 20130101;
H05B 1/0244 20130101; E03C 1/044 20130101; F24D 17/0026 20130101;
F24D 17/0089 20130101; F24H 9/2028 20130101 |
International
Class: |
F24H 9/20 20060101
F24H009/20; F24H 1/10 20060101 F24H001/10 |
Foreign Application Data
Date |
Code |
Application Number |
May 21, 2013 |
NZ |
610789 |
Claims
1-25. (canceled)
26. A fluid temperature modification apparatus which includes at
least one temperature modification element formed from an
electrically energised heating element sited inside a fluid conduit
associated with a fluid conduit, said temperature modification
element being located adjacent to an outlet of said fluid conduit,
and two or more banks of energy storage capacitors, and a plurality
of trigger switches, two or more of said trigger switches each
being connected to a separate bank of energy storage capacitors,
wherein the operation of a trigger switch connects one or more
energy storage capacitors to a temperature modification element,
wherein the operation of a trigger switch at least partially
discharges at least one energy storage capacitor bank to energise a
temperature modification element which modifies the temperature of
fluid in the conduit adjacent to the outlet port of the
conduit.
27. A fluid temperature modification apparatus as claimed in claim
26 which includes a plurality of temperature modification elements,
with one of the plurality of trigger switches being associated with
each temperature modification element.
28. A fluid temperature modification apparatus as claimed in claim
26 which includes an activation sensor adapted to issue a signal
which indicates when the outlet of the conduit has been opened.
29. A fluid temperature modification apparatus as claimed in claim
28 which includes an activation sensor formed from a flow rate
sensor.
30. A fluid temperature modification apparatus as claimed in claim
28 which includes a controller arranged to receive said indicative
activation signal from the activation sensor and to issue at least
one control signal to at least one trigger switch to operate said
trigger switch or switches based on the received activation
signal.
31. A fluid temperature modification apparatus as claimed in claim
26 wherein said at least one temperature modification element is
located in contact with a section of water plumbing conduit which
terminates in a hot water outlet.
32. A fluid temperature modification apparatus as claimed in claim
31 wherein the water plumbing conduit terminates in a hot water
outlet tap.
33. A fluid temperature modification apparatus as claimed in claim
26 wherein a temperature modification element is formed a
thermo-electronic cooling device which incorporates at least one
Peltier junction.
34. A fluid temperature modification apparatus as claimed in claim
26 which includes a capacitor recharge circuit configured to
recharge one or more at least partially discharged capacitors banks
at the same time as one or more charged capacitor banks are being
discharged.
35. A fluid temperature modification apparatus as claimed in claim
26 wherein a temperature modification element is energised by two
or more banks of capacitors.
36. A fluid temperature modification apparatus as claimed in claim
26 which includes a fast discharge capacitor bank and a high
storage capacitor bank, each of the fast discharge and high storage
capacitor banks being connected to a separate trigger switch.
37. A fluid temperature modification apparatus as claimed in claim
36 wherein the trigger switch connected to the fast discharge
capacitor bank is closed to energise a temperature modification
element once the opening of the outlet of the conduit has been
detected.
38. A fluid temperature modification apparatus as claimed in claim
37 wherein the trigger switch connected to the high storage
capacitor bank is closed to energise a temperature modification
element after the at least partial depletion of the fast discharge
capacitor bank.
39. A fluid temperature modification apparatus as claimed in claim
26 wherein an energy storage capacitor is provided by electrical
double layer capacitor.
40. A fluid temperature modification apparatus as claimed in claim
26 wherein a trigger switch is implemented using a solid state
semiconductor switch submerged in the fluid held by a conduit.
41. A fluid temperature modification apparatus as claimed in claim
26 wherein said at least one temperature modification element is
energised by a transformer isolated power converter and associated
electronic sub-systems providing a supply of DC electrical energy
from an AC source.
42. A fluid temperature modification apparatus as claimed in claim
41 wherein DC electrical energy supplied by the transformer
isolated power converter is used to re-charge the one or more
energy storage capacitors.
43. A fluid temperature modification apparatus as claimed in claim
41 wherein the trigger switch associated with the transformer
isolated power converter is closed to energise a temperature
modification element at substantially the same time as said one or
more energy storage capacitors are used to energise a temperature
modification element.
44. A fluid temperature modification apparatus as claimed in claim
26 wherein said at least one temperature modification element is
energised by a battery providing a supply of DC electrical
energy.
45. A fluid temperature modification apparatus as claimed in claim
44 wherein the trigger switch associated with the battery is closed
to energise a temperature modification element at substantially the
same time as said one or more energy storage capacitors are used to
energise a temperature modification element.
Description
FIELD OF THE INVENTION
[0001] This invention relates to a fluid temperature modification
apparatus. In a preferred embodiment the invention may be arranged
to deliver hot water from a hot water supply tap without a user
having to wait for cold water to be flushed out of a hot water
supply line.
BACKGROUND OF THE INVENTION
[0002] Plumbing and fluid conduit based systems have been developed
to allow fluid to be distributed to various points inside a
structure. These systems can be used to distribute a range of
fluids from a supply reservoir or a connection to a utility supply
network. In a variety of instances the temperature of these fluids
may need to be adjusted before they can be used in a desired
application.
[0003] Central fluid heating or cooling systems plumbed into supply
lines can adjust the temperature of a fluid prior to delivery.
However these systems will leave sections of supply line between
outlet ports and the temperature treatment system holding fluid,
and the fluid within ultimately ends up at the ambient
environmental temperature. The fluid within these sections of
supply line will need to be flushed out before fluid at a desirable
temperature is available at an outlet.
[0004] This approach will result in the fluid at ambient
temperature being wasted, with wastage accumulating to significant
volumes both over time and within supply networks having multiple
fluid outlets serviced by a single temperature treatment
system.
[0005] For example, in houses and apartment blocks hot water can be
delivered to multiple outlet taps from a central tank of heated
water. Water users who turn on hot water delivery taps will
typically have to run the tap for 5-40 seconds to flush out water
at the ambient temperature. The entire volume of water trapped in
the plumbing between the tap and central hot water tank will need
to be flushed out and is generally allowed to run down a drain.
[0006] This wastage of water is a concern to both householders and
water supply utilities. Furthermore, householders find it
inconvenient to have to wait for cold water to be flushed out of a
tap before they have hot water delivered.
[0007] To combat this problem it would be possible to install
additional heating or cooling systems adjacent to an outlet port or
tap. However, in these buildings electrical energy is generally
delivered by alternating current ("AC"). These AC systems generally
run at either 230V at 50 Hz or 110-120V at 60 Hz. Having AC power
supplied to electrical components in the vicinity of fluids such as
water can create safety issues, and these problems are normally
addressed by using a transformer isolated power converter to
provide galvanic isolation and convert the available AC power into
a direct current supply.
[0008] Although transformer isolated technology and associated
circuitry can allow AC or DC current to be supplied safely the
vicinity of a fluid outlet tap, the internal construction of the
transformer places significant restrictions on how quickly
energising current can be supplied to an associated heating coil.
In particular, transformers are not able to supply a high enough
energising current quickly enough for users wishing to have
immediate access to hot water.
[0009] A similar situation is applicable with heating or cooling
systems powered by existing electrical battery technology. The
relatively high internal resistance of existing batteries limits
their capacity to supply instantaneous high power, with the
internal resistance of the battery also increasing as it is
discharged. Additionally, battery lifetime will be limited by the
requirement for repeated high power discharge cycles.
[0010] It would therefore be of advantage to have an improved fluid
temperature modification apparatus which addressed any or all of
the above issues, or at least provided the public with an
alternative choice. In particular it would be of advantage to have
an apparatus which could modify the temperature of fluid stored in
the supply line prior to the fluid reaching the delivery outlet
from a central temperature treatment system. An additional
advantage would be the ease of installation of such a device,
enabling plumbers to retrofit into existing fluid supply lines. It
would also be of advantage in domestic applications to have an
apparatus which could almost instantly deliver hot water from a hot
water tap without a user having to wait for cold water to be
flushed out of a hot water supply line.
DISCLOSURE OF THE INVENTION
[0011] According to one aspect of the present invention there is
provided a fluid temperature modification apparatus which includes
[0012] at least one temperature modification element associated
with a fluid conduit, said temperature modification element being
located adjacent to an outlet of said fluid conduit, and [0013] at
least one energy storage capacitor, and [0014] at least one trigger
switch which when operated connects one or more energy storage
capacitors to a temperature modification element, wherein the
operation of a trigger switch at least partially discharges at
least one energy storage capacitor to energise a temperature
modification element which modifies the temperature of fluid in the
conduit adjacent to the outlet port of the conduit.
[0015] According to a further aspect of the present invention there
is provided a fluid temperature modification apparatus
substantially as described above wherein a trigger switch is
associated with a bank of energy storage capacitors and a
temperature modification element.
[0016] According to a further aspect of the present invention there
is provided a fluid temperature modification apparatus
substantially as described above which includes a plurality of
trigger switches, two or more of said trigger switches each being
connected to a separate bank of energy storage capacitors.
[0017] According to yet another aspect of the present invention
there is provided a fluid temperature modification apparatus
substantially as described above
[0018] which includes a plurality of temperature modification
elements, with one of a plurality of trigger switches being
associated with each temperature modification element.
[0019] According to a further aspect of the present invention there
is provided a fluid temperature modification apparatus
substantially as described above wherein said at least one
temperature modification element is energised by a transformer
isolated power converter and associated electronic sub-systems
providing a supply of direct current (DC) electrical energy from an
alternating current (AC) source.
[0020] According to another aspect of the present invention there
is provided a fluid temperature modification apparatus
substantially as described above which includes an activation
sensor adapted to issue a signal which indicates when the outlet of
the conduit has been opened.
[0021] Preferably an activation sensor can be formed from a flow
rate sensor.
[0022] According to a further aspect of the present invention there
is provided a fluid temperature modification apparatus
substantially as described above which includes a controller
arranged to receive said indicative activation signal from the
activation sensor and to issue at least one control signal to at
least one trigger switch to operate said trigger switch or switches
based on the received activation signal.
[0023] According to a yet further aspect of the present invention
there is provided a fluid temperature modification apparatus
substantially as described above which also includes
[0024] an inlet temperature sensor arranged to provide a signal
indicative of the temperature of fluid entering the fluid conduit,
and
[0025] a controller arranged to receive said indicative temperature
signal from an inlet temperature sensor and to issue at least one
control signal to at least one trigger switch to operate said
trigger switch or switches
[0026] According to yet another aspect of the present invention
there is provided a fluid temperature modification apparatus
substantially as described above which also includes
[0027] an inlet temperature sensor arranged to measure the stored
fluid temperature, and
[0028] an output temperature sensor arranged to provide a signal
indicative of the temperature of fluid leaving a fluid conduit
outlet, and
[0029] a controller arranged to receive said indicative temperature
signal from the temperature sensors and to issue at least one
control signal to at least one trigger switch to operate said
trigger switch or switches based on at least in part the received
indicative temperature signals.
[0030] Preferably the controller is arranged to issue at least one
control signal to operate said trigger switch or switches based on
a combination of an indication of conduit fluid flow rate provided
by an activation sensor and the received indicative temperature
signals received from the inlet and outlet temperature sensors.
[0031] The present invention is arranged to provide a temperature
modification apparatus used in conjunction with a fluid conduit.
The invention is to be located adjacent to an outlet of this fluid
conduit and is to be used to modify the temperature of fluid stored
in the supply conduit to facilitate prompt delivery of fluid at or
near a desired temperature.
[0032] Those skilled in the art will appreciate that conduits have
a significantly greater length than diameter and are usually closed
by a terminating valve or similar component. The conduits with
which the present invention are employed will therefore immediately
allow for the delivery of fluids once a user has made a demand for
these fluids.
[0033] In a preferred embodiment the invention may be used in a
domestic hot water heating application. In this application the
fluid to be modified is water at ambient temperatures which is
located in a section of plumbing conduit which runs between a
central hot water supply system and an outlet hot water tap. In
such embodiments the invention includes at least one temperature
modification element located in contact or association with a
section of plumbing conduit which extends from a wall or similar
structure and which terminates in a hot water outlet such as a hot
water tap.
[0034] In other embodiments the invention may be used to heat or
cool other types of fluids in a variety of applications. For
example in alternate applications the invention may be used to heat
raw material fluids which are employed in a production process and
are delivered via conduit from a main reservoir. In yet other
embodiments the invention may--for example--be used to cool
beverages delivered via supply lines in public bars.
[0035] Reference throughout this specification will in the main be
made to the invention being used to heat water in a domestic hot
water supply application. However those skilled in the art will
obviously appreciate that the invention may be used in other
applications and reference to the above should in no way be seen as
limiting.
[0036] The invention includes at least one temperature modification
element which -when energised- is arranged to heat or cool fluid
contained within a conduit. As referenced above, in a preferred
embodiment a temperature modification element may be arranged to
heat water in a section of conduit adjacent to a hot water tap.
[0037] In such preferred embodiments a temperature modification
element may be formed by an electrically energised heating coil
sited inside a conduit and in direct contact with water or other
fluid to be heated. A heating coil can be supplied with an
electrical current so that the coils electrical resistance will
result in the heating of water in the conduit.
[0038] In other embodiments however a temperature modification
element may be arranged to cool fluid within a conduit. For
example, in one alternative embodiment the invention may implement
temperature modification elements in the form of thermo-electronic
cooling devices which incorporate at least one Peltier
junction.
[0039] Reference throughout this specification will however be made
to a temperature modification element being formed from a heating
coil, although those skilled in the art will appreciate that other
components may be employed in various alternative embodiments.
[0040] In a preferred embodiment the invention includes a plurality
of temperature modification elements. Each temperature modification
element may be energised by at least one capacitor, and in
preferable embodiments energised by a bank of capacitors.
[0041] In some embodiments a temperature modification element may
be energised by two or more banks of capacitors. For example, in
one potential embodiment the invention may include a fast discharge
capacitor bank and a high storage capacitor bank, each of the fast
discharge and high storage capacitor banks being connected to a
separate trigger switch.
[0042] Preferably in such embodiments the trigger switch connected
to the fast discharge capacitor bank is closed to energise a
temperature modification element once the opening of the outlet of
the conduit has been detected. In such embodiments the trigger
switch connected to the high storage capacitor bank can be closed
to energise a temperature modification element after the at least
partial depletion of the fast discharge capacitor bank.
[0043] In yet other embodiments a temperature modification element
may be energised by a transformer isolated power converter and
associated electronic sub-systems providing a supply of DC
electrical energy from an AC source. In such embodiments the
trigger switch can be closed to energise a temperature modification
element at substantially the same time as said one or more energy
storage capacitors are used to energise a temperature modification
element.
[0044] Reference throughout this speciation has also been made to
the invention employing a transformer isolated power converter and
associated electronic sub-systems in various roles in a number of
embodiments. Those skilled in the art will appreciate that this
component may take a range of forms from a traditional large
stand-alone transformer through to small integral high frequency
ferrite or similar components which can perform in the same
function.
[0045] Furthermore, in one particular embodiment the invention may
be implemented by a combination of three separate heating
coils--each energised respectively by a fast discharge capacitor
bank, a high storage capacity capacitor bank, and a transformer
isolated power converter providing a supply of DC electrical energy
from an AC source.
[0046] The invention employs at least one energy storage capacitor
which is at least partially discharged to energise at least one
temperature modification element.
[0047] In a preferred embodiment the invention may employ large
capacitors provided by electrical double layer capacitors. These
EDL or electrical double layer capacitors are also known as super
capacitors, ultra-capacitors, pseudo capacitors or
cap-batteries.
[0048] EDL capacitors have a high capacitance giving these
components and their associated circuitry high relative time
constants. Due to the nature of their construction and size, EDL
capacitors have relatively large energy storage capacity and can be
discharged at a high rate of power.
[0049] Reference throughout this specification will also be made to
the invention employing large capacitors formed from or provided by
EDL capacitors. However those skilled in the art will appreciate
that the present invention may also be implemented through other
forms of suitable capacitors.
[0050] According to one aspect of the invention there is provided a
trigger switch used to connect a temperature modification element
to a source of energy such as a capacitor bank, or a DC current
supply provided by a transformer isolated power converter. Trigger
switches associated with either or both of an energy source or
temperature modification element can allow a variety of energy
supply configurations to be developed.
[0051] For example in embodiments where the invention is used to
implement a fast discharge capacitor bank and a high-capacity
capacitor bank, the fast discharge bank can be discharged to a
heating coil as soon as the opening of the conduit outlet is
confirmed. A temperature sensor provided by the invention can
determine whether the fluid leaving the outlet has been heated
enough. After a threshold time since opening of the outlet, if the
fluid leaving the outlet requires further heating a trigger switch
associated with a high-capacity capacitor bank may be
activated.
[0052] As indicated above in various embodiments the invention may
provide a temperature modification element energised by an AC or DC
supply derived from a transformer isolated power converter. The
temperature modification element energised by the power converter
may also be connected to a trigger switch. The energisation of this
temperature modification element can then be triggered at the same
time as the outlet opens and in parallel with the temperature
modification element energised by a fast discharge capacitor bank
or high-capacity capacitor bank.
[0053] In a variety of embodiments a trigger switch may be deployed
or located within a fluid conduit and adjacent to a temperature
modification element. This arrangement of the invention also allows
any waste heat generated by the operation of the switch to be
delivered to fluid present in the conduit. In a number of such
embodiments trigger switches may be implemented using solid state
transistor or similar semiconductor based switches which can be
submerged in the fluid held by a conduit and still function
effectively.
[0054] Preferably in embodiments where the invention provides a
temperature modification element energised by a DC supply derived
from a transformer isolated power converter, these same energy
supply connections can be used to recharge the capacitor or
capacitors used by the invention. In some embodiments of the
invention at least one temperature modification element may be
energised by a battery providing a supply of DC electrical energy.
Batteries can provide an alternative source of electrical energy
which can complement the energy discharge characteristics of the
capacitors used with the invention.
[0055] Preferably in such embodiments the trigger switch associated
with the battery is closed to energise a temperature modification
element at substantially the same time as said one or more energy
storage capacitors are used to energise a temperature modification
element. This approach caters for the limited power capability of
battery systems, allowing capacitors to energise a temperature
modification element immediately, with a battery providing a
further energy source prior to the capacitors being fully
discharged.
[0056] In some embodiments the trigger switch associated with a
battery can be closed in a periodic or repeating fashion to
establish a duty cycle for the battery connection in some
circumstances. For example in some cases a pulse width modulation
connection scheme may be employed in conjunction with a battery
trigger switch to vary the heating or cooling contribution provided
by the battery. The effective duty cycle of this triggering signal
may for example be modified depending on the predicted energy
demands currently being placed on the invention.
[0057] In a preferred embodiment the invention may include a
capacitor recharge circuit configured to recharge one or more at
least partially discharged capacitor banks at the same time as one
or more charged capacitor banks are being discharged. This
capacitor recharge circuit can therefore allow different members of
the same bank of capacitors to be recharged while other members of
an alternative charged bank are being discharged.
[0058] In a preferred embodiment the invention may also include a
controller. This controller may be implemented through any
appropriate programmable device, but in a preferred embodiment may
be provided by a programmable microprocessor.
[0059] The controller may be connected to at least one temperature
sensor--referred to as an outlet temperature sensor--which is
capable of providing an indication of the temperature of fluid
leaving the outlet of the conduit. In additional embodiments the
controller may be connected to a further temperature
sensor--referred to as an inlet temperature sensor--which is
capable of providing an indication of the temperature of fluid
stored in a supply conduit.
[0060] In a further preferred embodiment the invention may also
incorporate an activation sensor capable of confirming that the
outlet of the conduit has been opened. For example, in one
embodiment this activation sensor may be formed by a fluid pressure
or flow sensor capable of signalling to the controller that the
outlet has been opened.
[0061] In a preferred embodiment an activation sensor may be
implemented by a flow rate sensor arranged to measure or indicate
the rate at which fluid is moving through the conduit associated
with the invention. In addition to detecting when the conduit has
been opened, these flow rate measurements -in combination with a
measurement of inlet and outlet fluid temperature-may be used to
calculate the energy demand currently required of the
invention.
[0062] The controller may also be programmed to issue activation
signals to trigger switches. The controller may be programmed to
monitor the performance of the invention and modify the connections
of the trigger switches accordingly. As indicated above in some
embodiments the controller may be able to calculate or estimate the
energy demands currently required of the invention. The controller
may control the selection of particular trigger switches and the
activation times for these trigger switches based on these energy
demands.
[0063] In addition in some embodiments this controller may also use
the signals or information provided by an outlet and/or inlet
temperature sensor(s) to modify the behaviour of the invention. In
particular the temperature of water provided by the outlet may be
monitored by the controller for safety reasons to ensure that the
temperature of the water supplied does not exceed a safe
temperature value.
[0064] In yet other instances the temperature reading provided by
an inlet temperature sensor can give an indication of the
temperature of fluid travelling through the conduit and towards the
remaining components of the invention. If the temperature sensed by
the inlet temperature sensor meet that required from the operation
of the invention, the invention may be deactivated.
[0065] Those skilled in the art will also appreciate that a
controller provided in conjunction with the invention may also
receive input signals from sensors other than just flow rate or
temperature sensors. Depending on the application in which the
invention is employed additional sensor input derived control
parameters may be considered by the controller in determining a
switching program for the invention's trigger switch or
switches.
[0066] The present invention may therefore provide many potential
advantages over the prior art, or in the least providing the public
with an alternative choice.
[0067] The invention may be used to almost immediately raise or
lower the temperature of a fluid leaving a conduit.
[0068] In a preferred embodiment this is achieved by activating a
set of heating coils powered by a combination of large capacitor
banks and an AC or DC current supply from a transformer isolated
power converter or a derived DC power supply. The discharge
characteristics of the capacitors used can rapidly supply
significant energy to a heating coil by suitably adjusting the
heating coil characteristics combined with capacitor bank
characteristics.
[0069] Different configurations of capacitor banks may also be
employed in situations where heating or cooling needs to be
conducted over longer periods of time. In these instances a
high-capacity capacitor bank may be used to energise a heating coil
after a fast discharge capacitor bank has been significantly
discharged.
[0070] In various embodiments the controller may allow for the
independent automatic operation and intelligent control of the
temperature modification apparatus provided. Manual user inputs are
not required to adjust the activation and behaviour of the
invention for it to function effectively and efficiently. The
invention can also perform to promptly heat or cool fluids where
the energy demands placed on it vary significantly and
unpredictably. For example, in the case of domestic hot water
supply applications the invention can perform effectively
irrespective of whether hot water is required for a 10 section
period, or for the duration of a shower. In embodiments where
multiple trigger switches and energy sources are provided the
controller may determine and execute a switching program which
allows for the prompt and preferably immediate delivery of fluids
at the correct temperature.
[0071] In addition in embodiments where inlet temperature values
are sensed a controller provided with the invention may disable its
operation if it determines that fluid at the correct temperature is
currently being delivered through the conduit involved. In
embodiments where the temperature of fluid provided at the outlet
of the conduit is monitored, the operation of the invention may
also be disabled if the sensed temperature is outside of a safe
operational range.
BRIEF DESCRIPTION OF THE DRAWING
[0072] Additional and further aspects of the present invention will
be apparent to the reader from the following descriptive embodiment
with reference to the accompanying drawing in which:
[0073] FIGS 1a and 1b provide a representative sketch of a fluid
temperature modification apparatus 1 as provided in a preferred
embodiment, and
[0074] FIG. 2 shows the steps executed within a switching control
algorithm executed by the controller used in accordance with a
further embodiment of the invention.
[0075] Further aspects of the invention will become apparent from
the following description of the invention which is given by way of
example only of a particular embodiment.
BEST MODES FOR CARRYING OUT THE INVENTION
[0076] FIGS 1a and 1b provide a representative sketch of a fluid
temperature modification apparatus 1 as provided in a preferred
embodiment. FIG 1a shows the elements of the invention associated
with a conduit, and FIG 1b illustrates the inputs and outputs of a
controller as used in the embodiment shown.
[0077] The apparatus 1 includes three temperature modification
elements implemented by heating coils 2.
[0078] These heating coils are located in the interior of a
conduit, which is provided in this embodiment by a domestic hot
water supply line 3.
[0079] The hot water supply line 3 is supplied with hot water
originating from a boiler tank 4. The boiler tank 4 is centrally
located within the building housing the apparatus and is arranged
to feed a large number of hot water supply lines.
[0080] Without the operation of the invention hot water could not
be rapidly delivered to a user operating a hot water outlet tap 5
connected to the hot water supply line 3. The user of the tap 5
will need to wait for the hot water from the boiler 4 to flush out
the intervening ambient temperature water currently held in the hot
water line 3.
[0081] Each of the heating coils 2 are connected to an energy
supply system in the form of either a fast discharge large
capacitor bank 6, a high-capacity large capacitor bank 7, or a
transformer isolated power converter 8. In other embodiments the AC
powered isolation transformer many alternatively be provided by, or
combined with a battery based energy supply system.
[0082] In this embodiment the fast discharge bank 6 will have an
energy storage capacity lower than the high capacity bank 7, but
will take much less time to recharge back to a full charge.
[0083] Each of the fast discharge 6, high-capacity 7 or transformer
isolated power converter 8 energy sources are connected to its own
dedicated heating coil 2.
[0084] Interrupting the connection of the energy source of each
heating coil 2 is a trigger switch 9. The operation of the trigger
switch is controlled by a microprocessor 13 (as shown in FIG 1b)
provided with inlet and outlet fluid temperature readings from
inlet and outlet temperature sensors 10, which are sited in
combination with a fluid pressure/flow sensor 11. These sensors can
detect whether the hot water tap 5 has been opened from a measured
flow rate value, the temperature of the water leaving the hot water
tap, and the temperature of the water travelling from a remote hot
water supply tank.
[0085] The controller is also capable of sending a similar form of
control signal to recharging connections 12 made between the
capacitor banks 6, 7 and the isolation transformer 8. These
connections are used to recharge each capacitor bank from the AC
power source associated with the transformer isolated power
converter 8 in periods with low demand for hot water.
[0086] The temperature and pressure/flow sensors 10, 11 provide
performance information to the controller which can adjust the
connections made by each capacitor bank trigger switch 9a or
inductor trigger switch 9b. The controller can implement various
combinations of capacitor bank and transformer energy supply
connections to raise the outlet water temperature above a threshold
temperature in the minimum period of time required to achieve
this.
[0087] For example, after a period of low demand for hot water, the
first use of the invention will result in hot water being present
in the conduit, where this water has a temperature above or near a
threshold temperature.
[0088] Subsequent openings of the tap in the short term will only
need this water to be heated slightly.
[0089] In this environment of increased frequency of demand the
fast capacitor bank will re-charge quickly in the periods available
between tap openings.
[0090] The high capacity bank may not need to be connected to its
heating coil in these circumstances, allowing it to recharge
un-interrupted from the transformer isolated power converter 8.
[0091] The input information provided to the controller can also be
used to modify the behaviour of the invention in a number of
additional way. For example in the embodiment shown, if a signal
provided by the flow sensor indicated the fluid flow rate has
dropped to zero with the hot water tap being closed, all the
trigger switches 9a, 9a, 9b can be opened by the controller.
Furthermore, if the inlet temperature sensor 11 indicates that hot
water from the hot water supply tank has now reached the hot water
tap, again all the trigger switches 9a, 9a, 9b can be opened by the
controller.
[0092] The tables below summarise the key variables that the
electronic control unit or controller used in the embodiment of
FIG. 1 independently assesses to quantify the energy to be
delivered. Table 1 and 2 are specific to the prompt delivery of hot
water to taps in domestic households, while Table 3 considers
energy requirements in alternative applications.
TABLE-US-00001 TABLE 1 Key dependencies Variable Notes Required
outlet Likely to be fixed between 40.degree. C. and 55.degree. C.
temperature Inlet temperature Dependent on season (i.e. could be
1.degree. C. in winter vs. 18.degree. C. in summer in New Zealand)
Flow rate Variable across households; however, likely to be between
5 and 8 L/min Volume to be heated Dependent on length of pipe run
between main water heater and outlet; however, likely to be between
2 and 4 L
TABLE-US-00002 TABLE 2 Potential use cases within the domestic
delayed hot water application Req. Outlet Inlet Flow Energy Temp.
Temp Rate Volume Power Required (.degree. C.) (.degree. C.) (L/min)
(L) (kW) (Wh) Scenario 1 40 18 5 2 7.5 50 Scenario 2 55 1 8 4 30
250
TABLE-US-00003 TABLE 3 Potential future water heating applications
Req. Outlet Inlet Flow Energy Temp. Temp Rate Volume Power Required
Application (.degree. C.) (.degree. C.) (L/min) (L) (kW) (Wh)
Alternative to 45 10 6 10 14.5 400 gas califont Alternative to 45
10 6 25 14.5 1000 under-sink tank Alternative to 100 10 6 25 37.5
2600 boiling tank Alternative to 45 10 6 120 14.5 4850 gas/electric
main water heating system
[0093] As indicated above Table 2 illustrates how the inlet water
temperature and measured water flow rate is assessed to determine
the energy required to deliver hot water promptly in this
application. This determination of specific on-demand energy
expenditure is used as an input parameter to a switching control
algorithm executed by the controller.
[0094] FIG. 2 shows the steps executed within a switching control
algorithm executed by the controller used in accordance with a
further embodiment of the invention. In this embodiment the
invention is provided with an equivalent implementation to the
embodiment discussed with respect to FIGS 1a, 1b, other than being
provided with an additional energy source in the form of a
battery.
[0095] At step A of this algorithm a test is made of the measured
flow rate of water travelling through a hot water supply conduit.
If no water flow is detected the controller deems that the hot
water tap terminating the conduit is closed, causing the algorithm
to wait until water flow is detected.
[0096] Step B is executed once water flows is detected to test
whether the temperature of water sensed by a water inlet
temperature sensor is less than a target temperature to be
delivered. If the temperature of the water in the conduit is at or
higher than the target temperature the algorithm loops back to step
A. Step C is executed if the inlet water temperature is below the
target temperature.
[0097] At step C the controller closes the trigger switch of a fast
discharge capacitor bank and closes the trigger switch of the
transformer isolated power converter. The controller then waits for
a period of five seconds before moving on to step D.
[0098] At step D the controller again tests for water flow in the
conduit, at step E tests the inlet water temperature, and at step F
tests the outlet water temperature. If there is no water flowing in
the conduit, if the inlet water temperature is up to the target
temperature, or if the outlet water temperature is up to the target
temperature then step G is executed. At step G all open trigger
switches are closed and the algorithm loops back to step A.
[0099] If none of these conditions are met then step H is executed.
At step H the trigger switch of the fast discharge capacitor bank
is opened and this capacitor bank is connected to a recharge
circuit. Also at step H the trigger switch of a high-capacity
capacitor bank is closed, and the trigger switch of a battery based
energy supply is activated with a low duty cycle pulse width
modulated trigger signal. The controller then waits for a period of
five seconds before executing step I.
[0100] At step I the controller again tests for water flow in the
conduit, at step J tests the inlet water temperature, and at step K
tests the outlet water temperature. If there is no water flowing in
the conduit, if the inlet water temperature is up to the target
temperature, or if the outlet water temperature is up to the target
temperature then step L is executed. At step L all open trigger
switches are closed and the algorithm loops back to step A.
[0101] If none of these conditions are met then step M is executed.
At step M the trigger switch of the battery based energy supply is
activated with a high duty cycle pulse width modulated trigger
signal. The controller then waits for a period of five seconds
before executing step N.
[0102] At step N the controller again tests for water flow in the
conduit, at step 0 tests the inlet water temperature, and at step P
tests the outlet water temperature. If there is no water flowing in
the conduit, if the inlet water temperature is up to the target
temperature, or if the outlet water temperature is up to the target
temperature then step Q is executed. At step Q all open trigger
switches are closed and the algorithm loops back to step A.
[0103] If none of these conditions are met then step R is executed.
At step R the trigger switch of high-capacity capacitor bank is
opened and this capacitor bank is connected to a recharge circuit.
The battery is then connected continuously, and the outlet
temperature is tested until it reaches the target temperature. Once
this occurs the closed battery and transformer isolated power
converter trigger switches are opened, the battery is connected to
a recharging circuit, and the algorithm loops back to step A.
[0104] In the preceding description and the following claims the
word "comprise" or equivalent variations thereof is used in an
inclusive sense to specify the presence of the stated feature or
features. This term does not preclude the presence or addition of
further features in various embodiments.
[0105] It is to be understood that the present invention is not
limited to the embodiments described herein and further and
additional embodiments within the spirit and scope of the invention
will be apparent to the skilled reader from the examples
illustrated with reference to the drawings. In particular, the
invention may reside in any combination of features described
herein, or may reside in alternative embodiments or combinations of
these features with known equivalents to given features.
Modifications and variations of the example embodiments of the
invention discussed above will be apparent to those skilled in the
art and may be made without departure of the scope of the invention
as defined in the appended claims.
* * * * *