U.S. patent application number 16/289045 was filed with the patent office on 2020-09-03 for system and method of hot water recirculation using a bi-directional cold-water supply line.
The applicant listed for this patent is Rinnai America Corporation. Invention is credited to Ansley Houston, Rohan Scafe.
Application Number | 20200277760 16/289045 |
Document ID | / |
Family ID | 1000004081656 |
Filed Date | 2020-09-03 |
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United States Patent
Application |
20200277760 |
Kind Code |
A1 |
Scafe; Rohan ; et
al. |
September 3, 2020 |
SYSTEM AND METHOD OF HOT WATER RECIRCULATION USING A BI-DIRECTIONAL
COLD-WATER SUPPLY LINE
Abstract
A recirculation pump system provides the ability to recirculate
water from a water heater outlet, back into a water heater inlet
through a cold-water supply line. The recirculation pump system
pumps heated water, which may have cooled to a sub-optimal
temperature, into a water heater. The recirculation pump system
provides the ability to use a plumbing network that does not
contain a dedicated recirculation line. The recirculation pump
system uses a water pump to circulate water, a temperature sensor
to control system activation based on water temperature, and a
check valve to control the direction of fluid flow. This
recirculation pump system provides a minimally invasive way to
install a recirculation system into a plumbing network that
otherwise would not be able to accommodate recirculation functions,
and service modern plumbing fixtures efficiently.
Inventors: |
Scafe; Rohan; (Peachtree
City, GA) ; Houston; Ansley; (Peachtree City,
GA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Rinnai America Corporation |
Peachtree City |
GA |
US |
|
|
Family ID: |
1000004081656 |
Appl. No.: |
16/289045 |
Filed: |
February 28, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F24H 1/101 20130101;
E03B 7/045 20130101; F04B 49/02 20130101; F24D 17/0078 20130101;
F04B 49/10 20130101; E03B 1/048 20130101 |
International
Class: |
E03B 1/04 20060101
E03B001/04; F04B 49/02 20060101 F04B049/02; F04B 49/10 20060101
F04B049/10; F24D 17/00 20060101 F24D017/00; E03B 7/04 20060101
E03B007/04; F24H 1/10 20060101 F24H001/10 |
Claims
1. A recirculation pump system comprising: an inlet adapted to be
fluidically connected to a hot-water supply line; an outlet adapted
to be fluidically connected to a cold-water supply line; a
temperature sensor configured to sense a temperature at the inlet;
a water pump configured to pump water from the inlet to the outlet
upon the temperature sensor detecting a lower threshold
temperature; and a check valve configured to prevent water flow
from the outlet to the inlet.
2. The recirculation pump system of claim 1 wherein the water pump
is further configured to stop pumping water from the inlet to the
outlet upon the temperature sensor detecting an upper threshold
temperature.
3. The recirculation pump system of claim 1, wherein the upper
threshold temperature is adjustable and may be set at 120 degrees
Fahrenheit.
4. The recirculation pump system of claim 1, wherein the lower
threshold temperature is adjustable and may be set at 110 degrees
Fahrenheit.
5. The recirculation pump system of claim 1, wherein the check
valve is configured to be positioned between the water pump and the
outlet.
6. A water recirculation system comprising: a heat engine, having a
cold-water inlet and a hot-water outlet, a hot-water supply line
adapted to be fluidically connected to the hot-water outlet; an
inlet adapted to be fluidically connected to the hot-water supply
line; an outlet adapted to be fluidically connected to a cold-water
supply line; the cold-water supply line adapted to be fluidically
connected to the cold-water inlet; a temperature sensor configured
to sense a temperature in the hot-water supply line; a water pump
configured to pump water from the hot-water supply line to the
cold-water supply line upon the temperature sensor detecting a
lower threshold temperature; and a check valve configured to
prevent water flow from the cold-water supply line to the water
pump.
7. The water recirculation system of claim 6, wherein the water
pump is further configured to stop pumping water in from the inlet
to the outlet upon the temperature sensor detecting an upper
threshold temperature.
8. The water recirculation system of claim 6, wherein the upper
threshold temperature is adjustable and may be set at 120 degrees
Fahrenheit.
9. The water recirculation system of claim 6, wherein the lower
threshold temperature is adjustable and may be set at 110 degrees
Fahrenheit.
10. The water recirculation system of claim 6, wherein the water
pump is configured to circulate water from the hot-water supply
line through the cold-water supply line to the cold-water inlet of
the heat engine.
11. The water recirculation system of claim 6, wherein at least one
or more plumbing fixtures are fluidically connected to the
hot-water supply line and the cold-water supply line.
12. The water recirculation system of claim 6, wherein the water
pump is coupled across the hot-water supply line, and the
cold-water supply line at a furthest plumbing fixture from the
hot-water outlet.
13. The water recirculation system of claim 11, wherein one or more
plumbing fixtures are fluidically connected between the furthest
plumbing fixture and the heat engine.
14. The water recirculation system of claim 10, wherein one or more
of the plumbing fixtures are configured to operate on a cycle that
draws an amount of water from the hot-water supply line that is
less than an amount of water in the hot-water supply line between
the hot-water outlet and the one or more of the plumbing
fixtures.
15. The water recirculation system of claim 6, wherein the heat
engine is a tankless water heater.
16. A method of recirculating hot water comprising: activating a
water pump in a water recirculation system; circulating, by the
water pump, water from a hot-water supply line through a cold-water
supply line to a cold-water inlet of a heat engine inlet;
circulating, by the water pump, water from a hot-water outlet of
the heat engine to the hot-water supply line; measuring a
temperature of the water in the hot-water supply line; deactivating
the water pump when the water reaches an upper threshold
temperature.
17. The method of recirculating hot water of claim 16, further
comprising: reactivating the water pump when the water in the
hot-water supply line falls below a lower threshold
temperature.
18. The method of recirculating hot water of claim 16, wherein the
upper threshold temperature is adjustable and may be set at 120
degrees Fahrenheit.
19. The method of recirculating hot water of claim 17, wherein the
lower threshold temperature is adjustable and may be set at 110
degrees Fahrenheit.
20. The method of recirculating hot water of claim 16, wherein the
heat engine is a tankless water heater.
Description
BACKGROUND
[0001] The need for heated fluids, and heated water, has long been
recognized. Conventionally, water has been heated by water heaters
containing heating elements. These water heaters are conventionally
heated either electrically or with gas burners, where the heated
water may be stored in a tank or reservoir. Additionally, such
water heaters may be tankless, circulating hot water into a
plumbing system without storing the water in a tank or reservoir.
Water heaters are often used in private and commercial plumbing
networks. Plumbing networks often require water to be continuously
circulated into a heater to maintain a desired water temperature in
hot-water supply lines.
[0002] Many modern businesses, such as Quick Service Restaurants
(QSRs) for example, use existing water plumbing networks that are
not particularly configured for hot-water recirculation. As such,
these water plumbing networks often do not have a dedicated
hot-water recirculation line to reheat lukewarm water that may sit
in the plumbing network. But, many businesses use modern appliances
and plumbing fixtures, which may require hot water at a set
temperature. This set temperature may be necessary to meet safety
requirements. For example, some businesses use automatic dish
washers that use heated water to disinfect dirty dishes. Plumbing
fixtures in such applications often require a small amount of water
to operate, while drawing water from an extensive plumbing
network.
[0003] As water sits in an extensive plumbing network, the water
cools due to heat loss in the network's pipes, if the water is not
recirculated. A plumbing network may contain a large amount of
water, such as five gallons for example, between a water heater and
a plumbing fixture. In some applications, a plumbing fixture may
draw one to one and a half gallons of water in an operational
cycle, causing it to only draw lukewarm water. As such, there is a
need for a hot-water recirculation system that can operate in a
water circulation network that does not contain a dedicated
hot-water recirculation line.
SUMMARY
[0004] A first aspect of the disclosure provides a recirculation
pump system. The recirculation pump system comprises an inlet
adapted to be fluidically connected to a hot-water supply line. The
recirculation pump system comprises an outlet adapted to be
fluidically connected to a cold-water supply line. The
recirculation pump system comprises a temperature sensor configured
to sense a temperature at the inlet. The recirculation pump system
comprises a water pump configured to pump water from the inlet to
the outlet upon the temperature sensor detecting a lower threshold
temperature. The recirculation system comprises a check valve
configured to prevent water flow from the outlet to the inlet.
[0005] In some implementations of the first aspect of the
disclosure, the water pump is further configured to stop pumping
water from the inlet to the outlet upon the temperature sensor
detecting an upper threshold temperature.
[0006] In some implementations of the first aspect of the
disclosure, the upper threshold temperature is adjustable and may
be set at 120 degrees Fahrenheit.
[0007] In some implementations of the first aspect of the
disclosure, the lower threshold temperature is adjustable and may
be set at 110 degrees Fahrenheit.
[0008] In some implementations of the first aspect of the
disclosure, the check valve is configured to be positioned between
the water pump and the outlet.
[0009] A second aspect of the disclosure describes a water
recirculation system comprising a heat engine, having a cold-water
inlet and a hot-water outlet. The water recirculation system
comprises a hot-water supply line adapted to be fluidically
connected to the hot-water outlet. The hot water recirculation
system comprises an inlet adapted to be fluidically connected to
the hot-water supply line. The hot water recirculation system
comprises an outlet adapted to be fluidically connected to a
cold-water supply line. The cold-water supply line is adapted to be
fluidically connected to the cold-water inlet. The water
recirculation system comprises a temperature sensor configured to
sense a temperature in the hot-water supply line. The water
recirculation system comprises a water pump configured to pump
water from the hot-water supply line to the cold-water supply line
upon the temperature sensor detecting a lower threshold
temperature. The water recirculation system comprises a check valve
configured to prevent water flow from the cold-water supply line to
the water pump.
[0010] In some implementations of the second aspect of the
disclosure, the water pump is further configured to stop pumping
water in from the inlet to the outlet upon the temperature sensor
detecting an upper threshold temperature.
[0011] In some implementations of the second aspect of the
disclosure, the upper threshold temperature is adjustable and may
be set at 120 degrees Fahrenheit.
[0012] In some implementations of the second aspect of the
disclosure, the lower threshold temperature is adjustable and may
be set at 110 degrees Fahrenheit.
[0013] In some implementations of the second aspect of the
disclosure, the water pump is configured to circulate water from
the hot-water supply line through the cold-water supply line to the
cold-water inlet of the heat engine.
[0014] In some implementations of the second aspect of the
disclosure, at least one or more plumbing fixtures are fluidically
connected to the hot-water supply line and the cold-water supply
line.
[0015] In some implementations of the second aspect of the
disclosure, the water pump is coupled across the hot-water supply
line, and the cold-water supply line at a furthest plumbing fixture
from the hot-water outlet.
[0016] In some implementations of the second aspect of the
disclosure, one or more plumbing fixtures are fluidically connected
between the furthest plumbing fixture and the heat engine.
[0017] In some implementations of the second aspect of the
disclosure, one or more of the plumbing fixtures are configured to
operate on a cycle that draws an amount of water from the hot-water
supply line that is less than an amount of water in the hot-water
supply line between the hot-water outlet and the one or more of the
plumbing fixtures.
[0018] In some implementations of the second aspect of the
disclosure, the heat engine is a tankless water heater.
[0019] A third aspect of the disclosure describes a method of
recirculating hot water comprising activating a water pump in a
water recirculation system. The method of recirculating hot water
comprises circulating, by the water pump, water from a hot-water
supply line through a cold-water supply line to a cold-water inlet
of a heat engine inlet. The method of recirculating water comprises
circulating, by the water pump, water from a hot-water outlet of
the heat engine to the hot-water supply line. The method of
recirculating water comprises measuring a temperature of the water
in the hot-water supply line. The method of recirculating water
comprises deactivating the water pump when the water reaches an
upper threshold temperature.
[0020] In some implementations of the third aspect of the
disclosure, the method of recirculating water further comprises
reactivating the water pump when the water in the hot-water supply
line falls below a lower threshold temperature.
[0021] In some implementations of the third aspect of the
disclosure, the upper threshold temperature is adjustable and may
be set at 120 degrees Fahrenheit.
[0022] In some implementations of the third aspect of the
disclosure, the lower threshold temperature is adjustable and may
be set at 110 degrees Fahrenheit.
[0023] In some implementations of the third aspect of the
disclosure, the heat engine is a tankless water heater.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] For a more complete understanding of the present disclosure,
reference is now made to the following brief description, taken in
connection with the accompanying drawings and detailed description,
wherein like reference numerals represent like parts.
[0025] FIG. 1 illustrates a recirculation pump system diagram,
showing individual components.
[0026] FIG. 2 illustrates a water recirculation system diagram.
[0027] FIG. 3 illustrates a water recirculation system flow
chart.
DETAILED DESCRIPTION
[0028] It should be understood at the outset that although
illustrative implementations of one or more embodiments are
illustrated below, the disclosed systems and methods may be
implemented using any number of techniques, whether currently known
or in existence. Like numbers represent like parts throughout the
various figures, the description of which is not repeated for each
figure. The disclosure should in no way be limited to the
illustrative implementations, drawings, and techniques illustrated
below, but may be modified within the scope of the appended claims
along with their full scope of equivalents. Use of the phrase
"and/or" indicates that any one or any combination of a list of
options can be used. For example, "A, B, and/or C" means "A", or
"B", or "C", or "A and B", or "A and C", or "B and C", or "A and B
and C".
[0029] A recirculation pump system that comprises a temperature
sensor, a water pump and a check valve provides the ability to
recirculate water from a hot-water heater outlet, back into a water
heater inlet through a cold-water supply line. Such hot-water
bypass systems are particularly beneficial where a plumbing fixture
requires hot water at a set temperature, such as an automatic
dishwasher for example, is installed in an existing plumbing
network.
[0030] In such systems, the existing plumbing network often does
not contain a dedicated hot-water recirculation return line. A
temperature sensor may connect to a hot-water supply line that
contains heated water at a given time. The temperature sensor may
sense when water temperature falls below a certain preset
temperature. The temperature sensor may activate a water pump that
is fluidically networked to circulate water up a cold-water supply
line to a cold-water inlet on a water heater. A water circulation
system may utilize the water pump at a furthest fixture from the
water heater. When the water pump circulates the water, the water
heater may activate and heat the circulating water to replenish the
hot-water supply line with hot water at a heater set point
temperature.
[0031] The temperature sensor may also sense an upper threshold
water temperature and deactivate the water pump. This ensures that
water hotter than the upper threshold water temperature is not
circulated through the cold-water supply line in the water
circulation system. When the water cools again to the preset
temperature, due to heat loss in the plumbing network, the
temperature sensor may activate the water pump again.
[0032] The preset temperature and the upper threshold temperature
may be adjusted by a user. This allows a user to manage the
temperature of hot-water entering the cold-water supply line and
plumbing fixtures. As such, the adjustable preset temperature and
the upper threshold temperature allows the hot-water recirculation
system to provide hot water to fixtures at a desired temperature
while preventing excess hot water from overwhelming the cold-water
supply line. The temperature sensor further allows the hot-water
recirculation system to maximize energy efficiency by only
operating when necessary. The recirculation pump system may provide
a minimally invasive way to install a hot-water recirculation
system in a plumbing network that does into contain a hot-water
recirculation line. This is important in applications where modern
appliances may be installed in previously existing plumbing
networks, which are not designed to otherwise accommodate such
modern appliances and their heating requirements.
[0033] FIG. 1 illustrates a recirculation pump system 100, having a
hot-water line 102. The hot-water line 102 being fluidically
connected to a water pump 104 at a water pump inlet 104a. The water
pump 104 also having an outlet 104b. The water pump outlet 104b may
be fluidically connected to a check valve 106. The check valve 106
may be a spring check valve, such as a 3/4-inch spring check valve
for example. The check valve 106 may be configured to limit the
flow of water through the check valve 106 to a single direction--a
direction from the hot-water line 102 to a cold-water supply line
108, as shown. The check valve 106 may have an inlet 106a and an
outlet 106b wherein the check valve inlet 106a is fluidically
connected to the water pump outlet 104b and the check valve outlet
106b is fluidically connected to the cold-water supply line 108.
The cold-water supply line 108 may be configured to be fluidically
connected to a cold-water source (shown in FIG. 2) and a heat
engine cold-water inlet (shown in FIG. 2). In embodiments, the
check valve 106 may be located between the water pump, 110 and the
cold-water supply line 108 to restrict fluid flow to circulate out
of and away from the water pump outlet 104b, such that no cold
water may flow into the water pump outlet 104b.
[0034] The recirculation pump system 100 may be configured such
that the recirculation pump system 100 is controlled by a
temperature sensor 110. In embodiments, the temperature sensor 110
may be disposed about the hot-water line 102. The temperature
sensor 110 may comprise a sensing element, such as a copper sensing
element, that may sense the temperature of the hot-water line 102
through heat transfer through the hot water line 102. In some
implementations, the temperature sensor 110 may also sense the
water temperature by using a temperature probe to contact the water
directly. Other variations of the temperature sensor 110 are
contemplated by this disclosure.
[0035] The temperature sensor 110 may be programmable and may be
electrically connected to the water pump 104, such that the water
pump 104 may be activated when the temperature sensor 110 senses
that the water has reached a lower threshold temperature. In
embodiments, the lower threshold temperature of the water may be
110 degrees Fahrenheit. The temperature sensor 110 may also be
configured to deactivate the water pump 104 when the temperature
sensor 110 senses an upper threshold temperature. In embodiments,
the upper threshold temperature may be 120 degrees Fahrenheit or
greater. The temperature sensor may be a HONEYWELL AQUASTAT L6006C,
for example. The upper threshold temperature and/or the lower
threshold temperature may be programmatically adjusted on the
temperature sensor 110 to ensure that hot water at a desired
temperature is provided to fixtures at a desired temperature while
preventing excess hot water from overwhelming the cold-water supply
line.
[0036] FIG. 2 illustrates a water recirculation system 200 which is
configured to integrate the recirculation pump system 100 (shown in
FIG. 1) into a plumbing network. The recirculation pump system 100
has an inlet point 202 and an outlet point 204. The recirculation
pump system inlet point 202 is fluidically connected to the
hot-water line 102 and the recirculation pump system outlet point
204 is fluidically connected to the cold-water supply line 108. The
cold-water supply line 108 is fluidically connected to at least one
heat engine 206, at a water heater cold-water inlet 208. The at
least one heat engine 206 may also have a heat engine hot-water
outlet 210. The heat engine hot-water outlet 210 being fluidically
connected to the hot-water line 102. The hot-water line 102 and the
cold-water supply line 108 may each also be fluidically connected
to at least one plumbing fixture 212a-f. The hot-water line 102 may
route hot water from the at least one water heater 206 to the at
least one plumbing fixture 212a-f. The cold-water supply line 108
may also route cold water to the at least one plumbing fixture
212a-f. The cold-water supply line 108 may also be fluidically
connected to a cold-water source 214, such as a municipal water
supply, that may provide cold water to the at least one plumbing
fixture 212a-f and the heat engine cold-water inlet 208.
[0037] The recirculation pump system 100 may be disposed within the
water recirculation system 200. When the temperature sensor 110
senses a water temperature in the hot-water line 102 that is below
the lower threshold temperature, the water pump 104 may circulate
water from the hot-water line 102 into the cold-water supply line
108 and through the heat engine 204. As such, the recirculated hot
water may be fluidically connected to the cold-water source and the
at least one heat engine 204. Therefore, the water recirculation
system 200 uses the cold-water supply line 108 as a recirculation
path for the hot water as well as a cold-water supply path. In
embodiments, the at least one heat engine 204 may be a tankless
water heater, or multiple tankless water heaters, each fluidically
connected to the hot-water line 102 and the cold-water supply line
108. The at least one heat engine 204 may also be a tank water
heater, that heats water and stores it in a hot-water storage tank
(not shown).
[0038] FIG. 3 illustrates a flow diagram showing a process 300 for
recirculating hot water through a water recirculation system with
the water pump 104. At 302, the water pump 104 may be activated
remotely or locally. A user may activate the water pump 104 at the
time of desired operation, or a user may set a timer that activates
the water pump 104 automatically at a set time. The water pump 104
may also be electronically connected to a temperature sensor 110,
which may activate the water pump when it senses a certain
temperature, or range of temperatures. In some embodiments the
temperature sensor 110 may activate the water pump 104 upon sensing
a lower threshold temperature. The lower threshold temperature is
an adjustable temperature that may be a predetermined temperature
set by a user or otherwise programmed into the temperature sensor
110.
[0039] The water pump 104 may circulate the water from the
hot-water line 102 through the cold-water supply line 108 and into
the at least one heat engine 204. The at least one heat engine 204
may heat the water circulating therethrough 304. The at least one
heat engine 204 may be a water heater. In embodiments, the at least
one heat engine 204 may be a tankless water heater. The at least
one heat engine 204 may transfer heat to the water that is
circulating through it by conduction, or some other form of heat
transfer such as convection or radiation. The hot water may then be
circulated out of the at least one heat engine 204 into the
hot-water line 102 at a set point temperature.
[0040] A temperature sensor 110 may sense the temperature of the
hot water 306, by using a sensing element to take the temperature
of a surface of the hot-water line 102. In embodiments, the
temperature sensor may also take the temperature of the water in
the hot-water line 102 directly, using a probe disposed within
hot-water line 102. In embodiments, the temperature sensor may
deactivate the water pump 104 when the temperature sensor 110
senses an upper threshold temperature 306. The upper threshold
temperature is an adjustable temperature that may be a
predetermined temperature set by a user or otherwise programmed
into the temperature sensor 110. The temperature sensor 110 may be
electronically connected to the water pump 104, such that the
temperature sensor 110 signals the water pump 104 to deactivate
when it senses the upper threshold temperature.
[0041] The temperature sensor 110 may sense a lower threshold
temperature 308. In embodiments the temperature sensor 110 may
activate the water pump 104 upon sensing a lower threshold
temperature. The temperature sensor 110 may reactivate the water
pump as shown at 302. The water recirculation system 200 may
continue this cycle as long as a user intends to maintain hot water
in the water recirculation system 200.
[0042] While several embodiments have been provided in the present
disclosure, it should be understood that the disclosed systems and
methods may be embodied in many other specific forms without
departing from the spirit or scope of the present disclosure. The
present examples are to be considered as illustrative and not
restrictive, and the intention is not to be limited to the details
given herein. For example, the various elements or components may
be combined or integrated in another system or certain features may
be omitted or not implemented.
[0043] Also, techniques, systems, subsystems, and methods described
and illustrated in the various embodiments as discrete or separate
may be combined or integrated with other systems, modules,
techniques, or methods without departing from the scope of the
present disclosure. Other items shown or discussed as directly
coupled or communicating with each other may be indirectly coupled
or communicating through some interface, device, or intermediate
component, whether electrically, mechanically, or otherwise. Other
examples of changes, substitutions, and alterations are
ascertainable by one skilled in the art and could be made without
departing from the spirit and scope disclosed herein.
* * * * *