Note: Descriptions are shown in the official language in which they were submitted.
CA 02685787 2009-11-18
SYSTEM AND METHOD FOR ON DEMAND HOT WATER DISTRIBUTION
BACKGROUND
Related Applications
[001] The present application claims priority from U.S. Provisional
Application Serial No.
61/115,931 filed November 18, 2008, which is incorporated herein by reference
in its entirety for
all purposes.
Field
[002] The embodiments of the invention relates generally to systems and
methods for hot
water distribution and more particularly to systems and methods for on demand
hot water
distribution to one or more specified fixtures.
Background
[003] In conventional residential hot water systems, a cold water supply line
is provided to the
inlet of the water heater and a hot water distribution line exits from the
outlet of the water heater.
The hot and cold water distribution lines are then plumbed throughout building
to the various
fixtures located throughout the house.
[004] While conventional systems operate well to distribute water,
conventional systems are
not energy efficient and such systems result in a tremendous waste of water.
In a conventional
system, after each use the water in the hot water distribution line cools off,
consequently, when
a faucet is turned on, the water is usually cooler than desired and the user
allows the water to
run until the cooled off hot water is purged from the line and hot water
arrives at the fixture.
Waiting for the hot water to arrive is irritating to the user, and it
increases water consumption
resulting in an increase in the user's water bill.
[005] A number of systems have been developed in an attempt to solve this
problem. For
example, there are systems that circulate hot water continuously through the
hot water
distribution piping, and back to the water heater through a dedicated return
line. These types of
systems provide nearly instant hot water and eliminate water waste, but such
systems waste
significant energy. These systems result in hot water being circulated
throughout the
distribution system even if there is no demand for hot water. Keeping the
piping full of water
that is higher in temperature than the ambient temperature causes a large loss
of heat energy,
in order to keep the temperature up, more energy is used which increases the
user's energy bill
and greenhouse gas emissions.
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[006] In an attempt to curtail the energy use described in the constant
circulating hot water
systems, many users put such systems on a timer so that the system runs only
during hours of
normal use. This creates an inconvenience when hot water is desired during off
hours, and still
is very costly and wastes energy. Another problem with this type of system is
that if the home
was not plumbed with a hot water return line, it can be very expensive to add
plumbing to an
existing home. Moreover, this type of system will not work with a tankless
water heater.
[007] In an alternative to a designated hot water return line, some
conventional circulating
systems use the cold water distribution line as the hot water return line. One
such system is
described in U.S. Patent No. 5,829,467. The system discloses a pump located at
the water
heater and special temperature sensing cross over valves at the fixtures. The
pump runs
continuously, but can only make water flow if one or more of the cross-over
valves at the
fixtures is open. The valves are open if the water passing through them is
cold, and when the
water reaches a preset temperature the valve closes. This keeps warm water
near the fixtures
and thus reduces the wait for hot water.
[008] However, disadvantageously, this type of system results in the hot water
distribution
piping being full of above ambient temperature water all the time and much if
not all of the cold
water distribution lines are also above ambient temperatures. Consequently,
there is a huge
amount of energy wasted, greenhouse gas emissions are increased and it is very
costly to
operate. This type of system also does not work with tankless water heaters.
[009] The reason these systems will not work with tankless water heaters is
because tankless
water heaters are turned on when water flows through them and activates a flow
switch. These
types of circulating systems do not produce enough flow to turn on a tankless
water heater.
Excess water flow voids the warranty on tankless systems.
[0010] Furthermore, many homeowners don't like the above described systems
because
lukewarm water as opposed to cold water is distributed when a cold fixture is
opened. These
systems require the line to be purged in order to get cold water, resulting in
a waste of energy
and water.
[0011 ] Another type of system, for example the Laing System, uses a small
pump and valve at
a fixture. The pump runs periodically to keep the water at the fixture above
ambient
temperature. When the water at the fixture cools to a preset temperature the
pump turns on
and when the water reaches another preset elevated temperature the pump turns
off. Like the
above described systems this system results in the hot water piping and much
of the cold water
piping to be at above ambient temperatures and thus wastes energy. In
addition, this system
only serves the site where the pump and valve are located and any fixtures
directly between the
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pump/fixture and the water heater. As with the previous system cold water is
harder to obtain,
and the Laing systems do not work with tankless water heaters.
[0012] Yet another type of system that uses the cold water line as a hot water
return line is a
demand type system. With this type of system the user needs to "demand" hot
water by
pressing a button or otherwise activating the pump. The pump (and valve) is
located at the
fixture where the user desires fast hot water. When the user wants hot water
he activates the
pump, which begins pumping hot water from the water heater to the fixture.
When a sensor in
the pump detects an increase in temperature it shuts the pump off so that no
warm water enters
the cold water line. When the user turns on the faucet he only has to wait for
a few seconds for
hot water (not warm). This system results in less water running down the drain
unused while
waiting for hot water than other types of non-demand systems. By using a
powerful pump, the
water can be delivered very rapidly.
[0013] Another advantage of demand type systems is that they can be used with
tankless water
heaters. In fact, because it takes longer to get hot water with a tankless
water heater than with
a storage type water heater, demand systems are particularly useful for
tankless installations.
[0014] However, with most installations a demand system provides hot water to
only one or two
fixtures. To cover all of the fixtures requires multiple pumps. Even in
instances where one
pump can provide water to more than one fixture, it is not ideal situation
because it results in
filling more of the distribution piping with hot water than is needed to
provide the hot water to a
particular fixture.
[0015] An optimally efficient system only fills the piping between the water
heater and the fixture
being used with hot water, none of the systems currently available have this
advantage.
Embodiments of the present invention provide novel systems and methods of
efficiently
delivering hot water to any fixture in a home without running water down the
drain, and without
wasting energy. Furthermore embodiments of the present invention eliminate the
need for
multiple pumps, and provide novel systems that can be easily and inexpensively
retro-fitted to
existing homes, even homes with tankless water heaters.
SUMMARY
[0016] Embodiments of the present invention disclose systems and methods for
distributing hot
water on demand or on a specified schedule.
[0017] Further embodiments disclose a method of distributing hot water using a
distribution
system which includes a water heater, a pump with an electronic pump
controller, one or more
crossover valves with controllers, a cold water conduit, a hot water conduit,
one or more hot and
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cold water outlets, with the cold water conduit being coupled to the water
heater inlet, a source
of cold water, any cold water outlets at the fixtures, and the outlets of any
crossover valves, the
hot water conduit being coupled to the water heater outlet, any hot water
outlets at the fixtures,
the inlets of any crossover valves, and comprising the steps of: the user
activates a valve
controller at a particular fixture the valve controller checks the water
temperature at the valve,
and if the water temperature is above a specified value, the valve controller
does nothing if the
temperature is not above the value, the valve controller at that fixture opens
the valve and
sends a start signal to the pump controller the pump controller turns on the
pump the pump
controller optionally looks for a turn off signal when the valve controller
detects an increase in
temperature and sends a turn off signal to the pump controller, shutting the
pump off. If the
pump controller does not receive a turn off signal within a specified time
period the pump shuts
off anyway.
[0018] Still other embodiments provide a method of distributing hot water
wherein the user
activates a valve controller at a particular fixture The valve controller
checks the water
temperature at the valve, and if the water temperature is above a specified
value, the valve
controller and optionally emits a sound or signal to indicate to the user that
hot water is
available. If the water temperature is not above a designated temperature,
i.e., the water is not
hot, the valve controller at that fixture opens the valve, sends a start
signal to the pump
controller, and emits a sound to indicate hot water is on the way. The pump
controller then
turns on the pump and the pump operates to dispense hot water through the
distribution system
until an increase in temperature is detected. When the valve controller
detects an increase in
temperature it shuts off the valve, and optionally sends a stop signal to the
pump controller, and
emits a sound or signal to indicate to the user that the hot water has
arrived. The pump
controller shuts off the pump.
[0019] In an alternative embodiment, if the pump controller does not receive a
shut off signal
within a specified time period, such that hot water continues to flow through
the distribution
system, the pump automatically shuts off when the specified period of time has
elapsed.
However, if the none of the valves are open, the valve will automatically shut
down as there is
be no water flowing in the system.
[0020] In yet another embodiment, a system for distributing hot water includes
a water heater, a
pump with an electronic pump controller, one or more crossover valves with
controllers, a cold
water conduit, a hot water conduit, one or more hot and cold water outlets
where the cold water
conduit is coupled to the water heater inlet, a cold water source, at least
one cold water outlet at
the fixtures, and the outlets of any crossover valves, the hot water conduit
being coupled to the
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water heater outlet, at least one hot water outlet at the fixtures, and the
inlets of any crossover
valves. I
[0021] Embodiments of the present invention also provide a method for
distributing hot water
including a user activating a valve controller at a particular fixture, the
valve controller or
automatic device sending a pump controller a function code, the controller
receiving the code
and implementing a software program identified by the function code, Upon
completion of the
program the pump controller returning to the default program and awaits
further instructions.
[0022] In an alternative embodiment, an automatic device or sensor activates a
valve controller
at a specified fixture.
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BRIEF DESCRIPTION OF THE DRAWINGS
[0023] FIG. 1 depicts an embodiment of a system for hot water distribution;
[0024] FIG. 2 depicts an embodiment of a basic system for hot water
distribution; and
[0025] FIG. 3 depicts an embodiment of a basic system for hot water
distribution when
implemented with a dedicated return line.
DETAILED DESCRIPTION OF
PREFERRED EMBODIMENTS OF THE INVENTION
[0026] Various embodiments of the invention are described hereinafter with
reference to the
figures. It should also be noted that the figures are only intended to
facilitate the description of
specific embodiments of the invention. The embodiments are not intended as an
exhaustive
description of the invention or as a limitation on the scope of the invention.
In addition, an
aspect described in conjunction with a particular embodiment of the invention
is not necessarily
limited to that embodiment and can be practiced in any other embodiment of the
invention.
[0027] Throughout the specification and claims, the following terms take the
meanings explicitly
associated herein, unless the context clearly dictates otherwise. The phrase
"in one
embodiment" as used herein does not necessarily refer to the same embodiment,
though it may.
Furthermore, the phrase "in another embodiment" as used herein does not
necessarily refer to a
different embodiment, although it may. Thus, as described below, various
embodiments of the
invention may be readily combined, without departing from the scope or spirit
of the invention.
[0028] In addition, as used herein, the term "or" is an inclusive "or"
operator, and is equivalent
to the term "and/or," unless the context clearly dictates otherwise. The term
"based on" is not
exclusive and allows for being based on additional factors not described,
unless the context
clearly dictates otherwise. In addition, throughout the specification, the
meaning of "a," "an,"
and "the" include plural references. The meaning of "in" includes "in" and
"on." The term
"coupled" implies that the elements may be directly connected together or may
be coupled
through one or more intervening elements.
[0029] The present invention discloses embodiments of systems and methods for
distributing
hot water to a specified fixture. As will be appreciated by one of skill in
the art, the systems and
methods disclosed are equally applicable to residential, commercial and
industrial applications.
The purpose of the embodiments is to minimize the waste of water or energy in
distributing hot
water.
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[0030] As depicted in FIG. 1, embodiments of systems of the present invention
include a pump
3, a pump controller 4, a source of cold water 1, a water heater 2 with an
inlet and outlet 2B, 2A,
one or more fixtures 8, 12, 16 with hot and cold water outlets a cross over
valve 5, 11, 15 and
controller 6, 13, 17, at each fixture 8, 12, 16, a conduit in fluid
communication with the source of
cold water 9, the cold water outlets at the fixtures, the outlets of the cross
over valves 9A, 9B,
9C, and the water heater inlet 2B, a conduit in fluid communication with the
outlet 2A of the
water heater 10, the hot water outlets at the fixtures 8, 12, 16 and the
inlets of the cross over
valves 9D, 9E, 9F. Embodiments of the present invention further include a pump
activation
means comprising at least one of a number of possible devices such as but not
limited to
buttons, motion detectors, clock timers, and other mechanical and electronic
sensors.
[0031] When hot water is desired at a specified fixture, a pump activation
means communicates
with pump controller conveying to the controller at the outlet of the hot
water heater that hot
water is desired. The valve controller checks the water temperature at the
cross over valve to
make sure hot water is not already supplied to the specified fixture. If hot
water is not present at
the specified fixture, the valve controller sends the pump controller a start
signal and a function
code that selects the software program to be implemented by the pump
controller.
[0032] The pump controller obtains a function code. The function code is sent
to the pump
controller as a result of an initiating action at a select fixture. The
function code operates to
select the software program to be run by the pump controller. For example, the
function code
may direct the pump controller to run a program such that hot water is sent to
a single fixture, it
could direct the pump controller to run a program for freeze protection, or
any other pre-
established program for operating the hot water distribution system.
[0033] If for example the device is a simple button to obtain hot water from a
fixture, the valve
controller will first check the temperature of the water at that location. If
the temperature is
already high, the controller will beep twice which tells the user the water is
already hot. If the
temperature is not too hot, the controller beeps the activation device once
telling the user that
the hot water is on the way, and sends a signal to the pump controller
requesting service and
providing a function code. The valve turns on if the water is not already hot
when the button
was pressed.
[0034] The pump controller reads the function code and uses that to determine
which program
to run. If it is the function to obtain hot water, the pump turns on and pumps
until it receives a
stop signal or if no stop signal is received in a specified amount of time it
shuts off. If it is a
function to enter one of the other modes of operation then it does so.
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[0035] When a sensor in the valve senses an increase in temperature the valve
controller shuts
the valve, communicates with the pump controller telling it to shut off, then
beeps to let the user
know that hot water has arrived at the fixture.
[0036] If the activating device is an outdoor freeze protection temperature
monitor, the pump
controller would open all of the valves; turn on the pump, and then when the
last valve has
closed shuts the pump off, with the cycle repeating at regular intervals until
the danger is over.
[0037] A clock/timer device could be used to activate the system. The pump
controller and
valve controllers would receive a function code telling them to duplicate a
temperature
controlled type circulating system at one or more specified locations that
could be programmed
into the clock/timer device. This mode could last for a period programmed into
the clock/timer
device.
[0038] The activation devices can be manually operated buttons, motion
detectors, proximity
detectors, timers, clocks etc.
[0039] Turning now to the figure. FIG. 1 depicts a piping diagram of a system
for distributing hot
water. The distribution system includes: a pump, a pump controller, a source
of cold water, a
water heater with an inlet and outlet, one or more fixtures with hot and cold
water outlets, a
cross over valve and controller at each fixture, a conduit in fluid
communication with the source
of cold water, the cold water outlets at the fixtures, the outlets of the
cross over valves, and the
water heater inlet, a conduit in fluid communication with the outlet of the
water heater, the hot
water outlets at the fixtures and the inlets of the cross over valves.
Embodiments of the present
invention further include a pump activation means comprising at least one of a
number of
possible devices such as but not limited to buttons, motion detectors, clock
timers, and other
mechanical and electronic sensors.
[0040] When hot water is desired at a sink 8, a user presses a button 7. The
user initiates the
delivery process by pushing a button or activating a sensor in some way. The
button, motion
sensor, light beam, or whatever method is being employed to activate the
demand system as
described below to turn the pump on and open the valve associated with the
fixture in question.
The button 7 is wired to a controller 6 for a valve 5 at the sink 8. When the
button 7 is
depressed a program is initiated in the valve controller at the sink 8. The
controller 6 begins by
sampling the water temperature using a temperature sensor that is integral
with the valve and
the controller 5. Although described as integral with the valve and
controller, it is contemplated
within the scope of the embodiments of the present invention that the
temperature sensor could
be a separate device, could be integral with the fixture, ideally located at
the junction of the
fixture and the hot water inlet to the fixture, or positioned in any such way
that the temperature
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could be measured before dispensing the water through the fixture. If the
temperature is below
a critical value (i.e., a specified pre-designated temperature), the
controller 6 opens the valve 5,
and turns on a pump 3. An audible or visual signal is emitted to advise that a
request for hot
water has been made. The temperature sensor monitors the temperature at the
valve 5. When
the temperature sensor detects an increase in temperature of the water ,
preferably in the
range of 6 to 12 degrees, this range is not intended to be a limitation on the
embodiments of
present the invention, it sends a signal to the controller 6 to shut the valve
5 and pump 3 off. An
alternate sound or signal is emitted to indicate to the user that the hot
water has arrived.
[0041] If when the button 7 is pushed, the temperature sensor 6 senses an
already elevated
temperature, then it may not open the valve 5 or start the pump 3, but just
emitted an alternate
sound or signal to indicate that the water is already hot. Alternatively, if
an elevated
temperature is measured but the temperature is not within the specified
temperature range, the
valve 5 may be opened and the pump 3 run for a shorter period of time to
result in hot water at
the desired temperature at the fixture.
[0042] The valve controller 6 may automatically, without user intervention,
send a shut-down
signal to the pump controller 4 after a specified time period elapses, i.e.
three minutes, so that
hot water ceases to be pumped through the distribution system.
[0043] In another alternative embodiment, a motion detector could activate the
demand feature
as a user enters a bathroom or the kitchen, in this embodiment, similarly an
audible or visual
signal is emitted to signal hot water is on the way.
[0044] FIG. 1 also depicts the hot water distribution system operating as a
freeze protection
system for the potable water system. When operating as a freeze protection
system the
systems is initiated when the temperature outside of the house drops to
freezing or below.
When the external temperature drops, the external temperature activation
device 19 sends a
function code to the pump 3 which then sends commands to specified valves
located throughout
the distribution system 5, 11, 15 directing the various valves to open and
emitting a sound or
signal to alert potential users that the freeze protection mode has been
activated. When the
outside temperature rises above freezing or the system is not in danger of
freezing, the
activation device 19 communicates to pump controller 4 and the freeze
protection system is
deactivated. The system then returns to its demand mode of operation.
[0045] In an alternate embodiment, a signal from a clock timer activation
device 20 instructs the
pump controller 4 and designated valve controllers 5, 11, 15 to enter a
temperature controlled
circulating system mode. After a pre-programmed period of time, the clock
timer 20 sends a
signal to the pump controller 4 to return to demand system mode. When
operating in this mode,
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the system operates like a conventional demand system, but affording the
ability for hot water to
be available at all fixtures in the system. The clock timer activation device
20 can be user
programmed to provide hot water to one or more specified fixtures or even all
fixtures at once.
The clock timer device 20 also provides for user programming for any specified
period of time
that the system remains in a timer/temperature mode.
[0046] In the systems described, the pump and valve controllers are micro-
controller based.
The pump and valve controllers are controlled with software programming with
minimal interface
programs as is known to one of skill in the art. The pump may be any suitable
pump with the
capability to be electrically controlled. The more powerful the pump employed,
the more quickly
the hot water will arrive at the selected fixture. Similarly, any suitable
electrically controlled
valve or combination of valves may be used in the above described embodiments.
[0047] In various embodiments the pump controller, valves, and activation
devices
communicate with each other via hardwiring, through power line signals, or via
radio frequency
links. The valves and activation devices obtain power through the house wiring
alternatively, if
the system is a retrofit battery power or alternate power may be utilized. The
utilization of
battery power makes the system very easy to install even in retrofit
applications.
[0048] The pump controller, valve controllers, and activation devices may
employ
microcontrollers and associated circuitry to provide the various functions.
[0049] By using a large powerful pump and high flow valves the system may also
be
implemented in apartment buildings with central water heaters and other
commercial and
industrial applications.
[0050] In another embodiment, the on demand system is initiated without user
interaction when
a dishwasher is turned on, and the motor operates to open the drain valve, the
drain valve is
wired to a controller for a valve at the water inlet line. When the valve
opens a program is
initiated in the valve controller at the water inlet line. The controller
begins by sampling the water
temperature using a temperature sensor that is integral with the valve and the
controller.
Although described as integral with the valve and controller, it is
contemplated within the scope
of the embodiments of the present invention that the temperature sensor could
be a separate
device, could be integral with the dishwasher, ideally located at the water
inlet of the dishwasher
or positioned in any such way that the temperature could be measured before
dispensing the
water into the dishwasher. If the temperature is below a critical value (i.e.,
a specified pre-
designated temperature), the controller opens the valve, and turns on a pump.
In this
embodiment, it is not essential that an audible or visual signal is emitted to
advise that a request
for hot water has been made as the user is not waiting for hot water. The
temperature sensor
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monitors the temperature at the valve. When the temperature sensor detects an
increase in
temperature of the water, preferably in the range of 6 to 12 degrees, this
range is not intended
to be a limitation on the embodiments of the present the invention, it sends a
signal to the
controller to shut the valve and pump off. Optionally an alternate sound or
signal is emitted to
indicate to the user that the hot water has arrived.
[0051] In yet another embodiment, a user may initiate a signal for hot water
to be delivered to
the water inlet of the dishwasher by depressing button in communication with
the water inlet line
to the dishwasher in a manner similar as that described in conjunction with
hot water delivery at
a faucet.
[0052] In still another embodiment, the dishwasher may initiate a signal for
hot water when the
motor commences operation regardless of whether or not the drain valve opens.
[0053] In another embodiment, the high efficiency hot water delivery system is
simplified such
that the pump controller need not know which valve is turned it on. This
embodiment comprises
of a pump with controller at the water heater and a valve with controller
under the sink. The
pump is coupled to the water heater between the cold water supply and the
water heater inlet,
with the cold water distribution plumbing connection on the inlet side of the
pump.
[0054] A valve with integral temperature sensing means is coupled between the
hot and cold
supply lines at the fixture, and the valve controller has terminals for a
start button.
[0055] Pressing or otherwise engaging the start button causes the valve
controller to check the
water temperature. If the water is not already hot, the valve controller opens
the valve and
sends a start command to the pump controller which starts the pump. When hot
water reaches
the valve it closes, preventing heated water from entering the cold water
piping.
[0056] When the pump controller receives the start command from the valve
controller it turns
on the pump for a pre-determined and adjustable amount of time. The
predetermined amount
of time is preferably 3 minutes. However, it may be a longer or shorter period
of time, preferably
is it between 1 minute and 5 minutes.
[0057] Because the valve closes when the hot water reaches it, the pump can
keep running
with no adverse effects, because with the valve closed no flow will occur.
[0058] Pressing or otherwise engaging the button on any valve starts the pump
and sends the
hot water to the fixture for with the button was engaged and only that
fixture. If multiple valves
are activated at the same time then hot water will flow to each of the
fixtures and only those
fixtures where valves were activated.
[0059] The system also includes scald protection as there is the chance that a
user might
activate a valve while another user is taking a shower in another location.
Such activity could
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result in the pump causing a difference in pressure between the hot and cold
distribution
conduits resulting in the possibility of a scalding accident.
[0060] To prevent scalding, the pump controller may be connected to a flow
switch inserted into
the cold water conduit or otherwise placed to control flow. If water is
flowing into the house
plumbing, the controller will not allow the pump to turn on. If the pump is
already running it
shuts off. This eliminates the possibility of scalding.
[0061] In another embodiment, the system may be operated using a wireless or
other remote
system for activations. In such an embodiment the valve controller is mounted
under the sink
and has terminals to connect a start button. Alternatively it could also have
a built in RF
receiver allowing it to be activated wirelessly. the latter configuration
allows for convenient
night-stand placement of switches etc.
[0062] In another embodiment, the hot water flow may be activated without
specific user
intervention, i.e., proactively making a request by depressing a button or
taking other overt
action. In this configuration, the valve controller utilizes pressure or flow
sensing means for
activation. For example; briefly turning on the hot water faucet could be used
for activation
eliminating unsightly buttons.
[0063] In another embodiment, the hot water is activated by appliance use.
Utilizing flow
switches or current sensors, appliances such as dishwashers and washing
machines could
activate the valve controllers.
[0064] In still another embodiment, freeze protection is provided. An outdoor
temperature
sensor sends the valves a turn-on signal when the outside temperature drops
below freezing. It
then periodically activates the valve/controllers until the outdoor
temperature reaches a safe
level. The periodic circulation keeps the piping warm and protected from
freezing. In the case
of tankless water heaters this would also protect the heat exchanger from
freezing as well.
[0065] The various hot water distribution systems may also comprise timer
control. The
valve/controllers can respond to start commands from automatic timers or
clocks via the start
button terminals or via other communication methods.
[0066] The systems may also comprise a dedicated return line. When the system
is used to
replace a dedicated return line system a flow switch is located at the water
heater inlet or outlet
to sense hot water usage. When the flow switch detects hot water usage it
turns on the pump
for a fixed time period. The fixed period of time may be randomly set,
alternatively it may be
established or calculated based on the size of the system or the length of
pipe runs. For
example, it may be set to 2 minutes for a system with 100 feet of pipe, or 4
minutes with a
house with 200 feet of pipe. These examples are however non-limiting and the
time period could
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be adjusted as necessary to ensure proper delivery of the hot water. In
addition, the fixed
period of time may be preset and may vary depending on the time of day and day
of the week.
In addition the controller can differentiate between a very short usage of hot
water and a longer
run, turning on the pump only if the hot water is used very briefly. For
example, if the hot water
is turned on for 1 second or less the pump would start, but over one second
the pump would do
nothing.
[0067] In another embodiment the pump shuts off when it senses the arrival of
hot water at the
pump, and if hot water never arrives, the pump shut offs after a pre-set time
period, for example
but not limited to 3 to 5 minutes
[0068] Other and further embodiments of systems of the present invention
include a pump, a
pump controller, a source of cold water, a water heater with an inlet and
outlet, one or more
fixtures with hot and cold water outlets a cross over valve and controller at
each fixture, a
conduit in fluid communication with the source of cold water, the cold water
outlets at the
fixtures, the outlets of the cross over valves, and the water heater inlet, a
conduit in fluid
communication with the outlet of the water heater the hot water outlets at the
fixtures and the
inlets of the cross over valves.
[0069] Optionally embodiments of the system may include flow sensing/detection
means,
including but not limited to paddle type flow switches, and turbine type flow
sensors, connected
between the cold water source and the pump inlet and in communication with the
pump
controller, flow sensing means connected between the water heater outlet and
the hot water
distribution conduit and in communication with the pump controller, and flow
sensing means
connected between the hot water distribution conduit and the hot water faucet
and in
communication with the valve controller.
[0070] Embodiments of the present invention may further include valve
controller activation
means including but not limited to motion detectors, current sensors, photo
electric beams,
manual switches, and proximity switches, comprising at least one of a number
of possible
devices such as but not limited to buttons, motion detectors, clock timers,
flow sensors, current
sensors and other mechanical and electronic sensors.
[0071] When hot water is desired at a specified fixture, the valve controller
at that location is
activated causing the valve controller to check the water temperature, and if
the water
temperature is below a set point, the controller opens the valve and sends a
start command to
the pump which runs until the fixed run time has elapsed. When the valve
controller senses an
increase in temperature it closes the valve.
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CA 02685787 2009-11-18
[0072] In another embodiment, FIG. 2 depicts an embodiment of a basic system
for hot water
distribution 200. The system 200 includes a flow control means, i.e., a first
flow switch 210, to
detect the consumption of water. The flow switch 210 prevents a pump 220 from
starting or if
the pump 220 is already running a pump controller 230 shuts it off, preventing
the possibility of a
scalding injury.
[0073] As also shown in FIG. 2, a flow sensing means, i.e., a second flow
switch 240 (a...n) , is
located between a hot water distribution conduit 250 and a hot water fixture
260 (a...n). There
may be multiple flow sensing means in a single system such that a second flow
switch 240
(a...n) is located at each hot water fixture. When the flow sensing means
senses flow it
activates a valve controller 270 (a...n) initiating the circulation of hot
water.
[0074] Another embodiment of the system includes flow sensing means or current
sensing
means, such as series resistor sensing circuits, transformer type current
sensing circuits, and
clamp on current detectors in communication with the valve controller for
activation when an
external appliance such as a washing machine or a dishwasher begins operation.
[0075] Yet another embodiment of the system includes temperature sensing
means, including
but not limited to thermisters, thermocouples, bi-metallic contact sensors,
and integrated circuit
sensors located outdoors and in communication with the valve controllers to
activate the valve
controllers when the outdoor temperature drops below freezing.
[0076] In another embodiment, FIG. 3 depicts a basic system 300 for hot water
distribution
when implemented with a dedicated return line 310. The dedicated return line
employs a flow
sensing means 320, i.e., a flow sensor, between a water heater outlet 330 and
a hot water
distribution conduit 340 to activate a pump controller 350, which manages a
pump 360.
[0077] As depicted, the dedicated return line 310 is used to circulate unused
water back to a
water heater inlet 370. This system employs a temperature sensing means 380 in
communication with the pump controller 350 and shuts off the pump 360 when a
temperature
increase is detected. If no increase is detected the pump 360 shuts off after
a pre-set fixed time
period, for example but not limited to 3 to 5 minutes.
[0078] In the systems described above, the pump and valve controllers are
micro-controller
based. The pump and valve controllers are controlled with software programming
with minimal
interface programs as known to one of skill in the art. The pump may be any
suitable pump with
the capability to be electrically controlled. The more powerful the pump
employed, the more
quickly the hot water will arrive at the selected fixture. Similarly, any
suitable electrically
controlled valve or combination of valves may be implemented in the above
described
embodiments.
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CA 02685787 2009-11-18
[0079] In various embodiments the pump controller, valves, and activation
devices
communicate with each other via hardwiring, through power line signals, or via
radio frequency
links or any other system that enable communication. The valves and activation
devices may
obtain power through the house wiring. Alternatively, if the system is a
retrofit, battery power or
alternate power may be utilized. The utilization of battery power makes the
system very easy to
install even in retrofit applications.
[0080] Although the systems described above include a pump, any pumping means,
including
but not limited to centrifugal pumps, gear pumps, diaphragm pumps, piston
pumps, and turbine
pumps, are contemplated within the scope of the embodiments of the present
invention.
[0081] Although described in conjunction with a single use or single unit
application, such
description is not so limited and further expansions and implementations are
contemplated
within the scope of the embodiments of the present invention. The system is
equally applicable
for large scale or multi-unit use. By using a large powerful pump and high
flow valves the
system may be implemented in apartment buildings with central water heaters
and other
commercial and industrial applications.
[0089] As noted previously the forgoing descriptions of the specific
embodiments are presented
for purposes of illustration and description. They are not intended to be
exhaustive or to limit
the embodiments of the invention to the precise forms disclosed and obviously
many
modifications and variations are possible in view of the above teachings. The
embodiments
were chosen and described in order to explain the principles of the
embodiments of the
invention and its practical applications, to thereby enable those skilled in
the art to best utilize
the invention and various embodiments thereof as suited to the particular use
contemplated. It
is intended that the scope of the invention and embodiments thereof be defined
by the claims
and their equivalents.
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