U.S. patent application number 12/107824 was filed with the patent office on 2008-10-30 for tankless water heater hot water return system.
Invention is credited to Rich Grimes.
Application Number | 20080265046 12/107824 |
Document ID | / |
Family ID | 39885799 |
Filed Date | 2008-10-30 |
United States Patent
Application |
20080265046 |
Kind Code |
A1 |
Grimes; Rich |
October 30, 2008 |
TANKLESS WATER HEATER HOT WATER RETURN SYSTEM
Abstract
A tankless return hot water return system to facilitate
whole-house or whole-building hot water return recirculation used
in conjunction with tankless water heaters. The system is designed
to compensate for tankless head losses and to protect the tankless
heat exchanger. The system has a hot water return by-pass for heat
exchanger protection. The invention utilizes the tankless water
heater as the heating source for the hot water return and
eliminates the need and use of tank-type water heaters for tankless
hot water return recirculation. The system is self-contained with
built-in temperature sensing and does not require any auxiliary
controls, sensors, switches, timing mechanisms or remote
activation. The system is energy efficient and water
conservative.
Inventors: |
Grimes; Rich; (Orlando,
FL) |
Correspondence
Address: |
DONALD W. MEEKER
924 EAST OCEAN FRONT, # E
NEWPORT BEACH
CA
92661
US
|
Family ID: |
39885799 |
Appl. No.: |
12/107824 |
Filed: |
April 23, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60913998 |
Apr 25, 2007 |
|
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|
60914001 |
Apr 25, 2007 |
|
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Current U.S.
Class: |
237/19 |
Current CPC
Class: |
F24D 17/0078 20130101;
F24D 19/1051 20130101 |
Class at
Publication: |
237/19 |
International
Class: |
F24D 3/08 20060101
F24D003/08 |
Claims
1. A tankless hot water return recirculation system integrated into
a tankless hot water distribution heater and pipe array, the system
comprising: a hot water return recirculation system alternately
connected to and isolated from a tankless hot water heater having a
cold water feed pipe and a hot water distribution pipeline, the hot
water return recirculation system comprising a recirculation
pipeline connecting between the hot water distribution pipeline and
the tankless hot water heater for pumping previously heated warm
water from the hot water distribution pipeline back through the
recirculation pipeline to the tankless hot water heater for
reheating the warm water in the hot water heater to send the
reheated water back through the hot water distribution pipeline for
use; means for opening and closing a pipeline connection between
the hot water distribution pipeline and the water recirculation
pipeline; means for opening and closing a pipeline connection
between the recirculation system and the tankless hot water heater
cooperating with means for opening and closing the return water
feed pipeline connection to the tankless hot water heater; an
inline water recirculation pump to pump the warm water from the hot
water distribution pipeline to the tankless water heater; a
temperature sensor in the hot water distribution pipeline; and a
two stage electronic temperature control communicating with the
temperature sensor, the recirculation pump, and the means for
opening and closing the pipeline connections to activate the
recirculation pump to activate a flow of warm water from the hot
water distribution pipeline to the tankless hot water heater for
heating the warm water when the warm water in the hot water
distribution pipeline reaches a low set temperature and to
deactivate the recirculation pump and switch back the means for
opening and closing pipeline connections when the water temperature
reaches a set high temperature to isolate the hot water return
recirculation system from the tankless hot water heater and the hot
water distribution pipeline.
2. The system of claim 1 wherein the means for opening and closing
the pipeline connection between the hot water distribution pipeline
and the water recirculation pipeline comprises a normally closed
solenoid valve in the recirculation pipeline which opens to admit
heated water from the hot water distribution pipeline into the
water recirculation pipeline or closes to bypass the heater.
3. The system of claim 2 further comprising a normally partially
open recirculation pump valve in the recirculation pipeline for
water prime to the recirculation pump and to serve as a secondary
by-pass line in the event of the solenoid valve failure.
4. The system of claim 1 wherein the hot water pipelines further
comprise an outer layer of thermal insulation to minimize radiation
heat loss therefrom.
5. The system of claim 1 wherein the recirculation pump of the
present invention is structured to function in accordance with the
tankless water heater requirements, flow rates and hot water
heating modulation.
6. The system of claim 1 wherein the hot water return recirculation
system is configured for whole house hot water recirculation with
modulating tankless water heaters.
7. The system of claim 1 wherein the hot water return recirculation
system protects the tankless water heater from direct recirculation
from the hot water distribution pipeline.
8. The system of claim 1 wherein the hot water return recirculation
system is configured to operate with a continuous hot water return
pump.
9. The system of claim 1 wherein the hot water return recirculation
system is configured to operate with an intermittent hot water
return pump.
10. The system of claim 1 wherein the hot water return
recirculation system is connected to the modulating burner of the
tankless water heater for use of the tankless water heater as a hot
water return heat source.
11. The system of claim 1 further comprising a hot water return
check valve located on a lower by-pass pipe of the hot water
distribution pipeline to insure that flow can only be directed in
one direction, away from the tankless heater and directed toward
the hot water return and supply loop.
12. The system of claim 1 wherein the hot water return
recirculation system is connected to a tankless water heater with
traditional hot water return.
13. The system of claim 1 wherein the hot water return
recirculation system compensates for the head losses of the
tankless heater to allow for whole-house and whole-building hot
water return.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present utility patent application claims the advantage
of provisional applications #60/914001 and #60/913998 both filed
Apr. 25, 2007.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] Not Applicable.
THE NAMES OF THE PARTIES TO A JOINT RESEARCH OR DEVELOPMENT
[0003] Not Applicable.
BACKGROUND OF THE INVENTION
[0004] 1. Field of the Invention
[0005] The present invention relates to plumbing systems and
particularly to a tankless water heating hot water return system
which comprises a plumbing system having a hot water recirculating
line which brings unused cooled "hot" water from the hot water
supply lines back to the hot water heater so that it may be
reheated and redirected to the hot water outlet, thereby conserving
water.
[0006] 2. Description of Related Art Including Information
Disclosed Under 37 CFR 1.97 and 1.98
[0007] Various hot water recirculating systems have been previously
designed, some for boiler-tank systems as documented in U.S. Pat.
No. 1,780,379 by Durdin, Jr. and also for use with tank-type water
heaters such as documented in U.S. Pat. No. 4,201,518 by
Stevenson.
[0008] Two of the biggest concerns we face today are escalating
energy costs and water conservation. Domestic hot water systems for
both commercial and residential applications consume energy for
heating and can contribute to waste of fresh water. Hot water
systems experience heat losses, increasing energy usage. Systems
that are not recirculated require running water down the drain
until hot water arrives.
[0009] Tankless water heaters are becoming a trend in domestic
water heating. They are displacing tank-type water heaters due to
their size, efficiency and due to the fact that they do not
experience the stand-by losses of tank-type water heater
technology. However, tankless water heaters do not accommodate
simple, whole-house hot water return like a tank-type heater does.
There are several methods for hot water return that are commonly
used with tankless water heaters. These methods were originally
designed for tank-type technology and have many drawbacks when
applied to tankless systems.
[0010] The design of a tankless water heater uses a copper heat
exchanger to transfer heat into the flowing water. The burner
transfers heat into the flowing water through the copper heat
exchanger. The heat exchanger has a very high head loss and this
complicates simple hot water recirculation. Attempts have been made
to come up with a method to resolve these drawbacks. These methods
either use enormous amounts of energy, flow directly into the
tankless heater and reduce or void its warranty, or service a
single fixture group.
[0011] The first method has been to directly recirculate back into
the water heater. This method, originally designed for a tank-type
water heater, is documented in U.S. Pat. No. 5,735,291 by Kaonohi.
This method is extremely stressful to the copper heat exchanger of
the tankless heater. It is not designed to withstand direct
circulation. This method of recirculation has been deemed by
tankless manufacturers as detrimental to their heat exchangers. As
a result, tankless manufacturers either greatly reduce or void
their heat exchanger warranties if they are installed with Direct
Recirculation.
[0012] The next method commonly used is to employ a tank-type water
heater to facilitate hot water return. The tank-type water heater
allows hot water to recirculate and functions as a buffer. The
tank-type heater does not have the head losses associated with
tankless heaters, so it can accept circulation. This method does
protect the tankless heater's heat exchanger, but it has
astronomical energy consumption. The tank-type water heater method
totally defeats the purpose of "Tankless" water heating and will
add back stand-by losses to the system. The KW input of an electric
tank-type water heater is not enough to efficiently heat the return
line. The electric element remains on any time the return pump is
active. This method actually uses more energy than a standard
tank-type water heater being used as the only water heating source.
This method also does not maintain system temperatures due to the
fact that the low-input tank-type water heater is trying to heat
the return line, not the Tankless heater.
[0013] The last method that is commonly used is to employ a
under-sink recirculation system. These systems draw hot water from
the hot water pipe and circulate the flowing water into the cold
water supply. These systems were originally designed for use with
tank-type water heaters but can be applied to tankless heaters.
[0014] Several of these prior art systems are documented, such as
U.S. Pat. No. 5,323,803 by Blumenauer, U.S. Pat. No. 5,277,219 by
Lund, U.S. Pat. No. 5,941,275 by Laing and U.S. Pat. No. 5,829,475
by Acker. These systems can deliver hot water, but only to a
specific fixture group. They do not address whole-house
recirculation and require activation. The systems are either
activated by flow, temperature, manual push button or motion
sensors. These systems can over-heat the cold water supply
resulting in increased energy costs. They can be useful in systems
that cannot accommodate a dedicated hot water return line.
[0015] Many gallons of water are wasted by turning on hot water
taps and showers and waiting until the cold water standing in the
hot water pipes passes through the tap. Without a recovery system
the water has simply been allowed to run down the drain thus not
only wasting good water but overburdening waste water treatment
plant with additional volumes of water.
[0016] Currently the prior art systems must have a storage tank or
electric storage heater to properly operate a recirculation system
with tankless water heaters.
[0017] U.S. Patent Application #20060022062, published Feb. 2, 2006
by Morris, is for an on-cue hot-water circulator consisting of an
electronic control module, a manifold containing a check valve
and/or a normally closed solenoid valve, a flow switch, and a
high-performance pump (not a typical circulation pump), that is
also designed or selected for its ability to allow water to pass
through it with little or no restriction, when not operating. In a
retrofit installation, the cold-water supply line is used for
returning purged water to the water heater.
Prior Art System with Basic HWR with Timer, Flow Switch--use of
Cold Water Line
[0018] U.S. Patent Application #20030089399, published May 15, 2003
by Acker, provides a smart demand hot water recirculation system
includes a hot water source and at least one plumbing fixture
having a hot water inlet. A pump is provided to circulate water to
and from the fixture and a controller, responsive to a plurality of
a generated control signals, based on fixture use, activates the
pump based on a statistical analysis of control signal timing.
Demand Type System Requiring External Controls/Basic HWR System
[0019] U.S. Patent Application #20050006402, published Jan. 13,
2005 by Acker, shows a method of operating a plumbing system and a
hot water recirculation system. The system generally comprises a
hot water source, for example a water heater, such as for example,
a gas, oil, solar or electric tanks or tankless heater,
interconnected by means of pipes with plumbing fixtures, said pipes
providing conduit means for enabling circulation of hot water from
said hot water source to each plumbing fixture and return to the
hot water source. The pipes are thus in fluid communication with
the hot water source and the plumbing fixtures in such a way as to
establish a hot water loop. This is mainly for a Pump Controller
that creates its own operating pattern
[0020] U.S. Patent Application #20060230772, published Oct. 19,
2006 by Wacknov, claims a system and method for efficient and
expedient delivery of hot water which detects and anticipates fluid
flow in a pipe utilizing a sensor, a processor, and a time base. In
an alternate system, a recirculation extension is included in
system, wherein an additional plumbing line attaches at a point of
the hot water plumbing system. The point of attachment is selected
to include as much of the hot water distribution system as possible
between hot water heater and the point of attachment. The
recirculation plumbing extends from the point of attachment and
returns to hot water heater at a second point. The hot water return
is shown as a separate conduit into the hot water heater. A pump is
often included to move water. The pump may run continuously or be
regulated by a number of control schemes.
Another Processor Pump Controller/Timing Sensitive
[0021] U.S. Pat. No. 5,277,219, issued Jan. 11, 1994 to Lund, is
for a hot water demand system suitable for retrofit. A control
system causes the pump to circulate water from the hot water line
into the cold water line and back to the hot water source when a
hot water valve on said plumbing fixture is turned on. A
temperature sensor stops the pump, via the control system, to
prevent heated water from being circulated through the cold water
delivery lines.
Basic Demand System for Single Fixture Requiring Activation, Remote
Sensors and Utilizing the Cold Water Piping.
[0022] U.S. Pat. No. 4,201,518, issued May 6, 1980 to Stevenson,
shows a recirculating hot water system which includes a hot water
supply pipe and a hot water return pipe connected in a loop between
a hot water outlet of a hot water tank and a return inlet to that
tank. An electrically controlled recirculating pump is placed in
the return pipe between the inlet to the hot water tank and the
supply pipe, which has hot water taps located at various points
along it.
Basic HWR for Tank-Type Heaters Requiring Manual Activation
[0023] U.S. Patent No. 5,572,985, issued Nov. 12, 1996 to Benham,
claims a recirculating system with a by-pass valve. The
recirculating hot water system comprises a boiler for heating a
continuous supply of hot water, a recirculating water line
comprising a supply line connected to an outlet of the boiler for
conveying water from the boiler to at least one use station and a
return line for returning water not consumed at the station to the
boiler, a circulating pump in the return line for continuously
circulating water in the water line, a by-pass circuit for
by-passing the recirculating line connected at an outlet of the
pump and an inlet to the pump, and a by-pass valve in the
recirculating line at the by-pass line for directing water at a
predetermined temperature through the by-pass line. For continuous
circulation only/Special Valve that regulates a variable flow
rate/By-Pass is for regulation of temperature
[0024] U.S. Pat. No. 4,606,325, issued Aug. 19, 1986 to Lujan, Jr.,
describes a water conservation system for use in residential
dwellings or other buildings having a hot water distribution
system. The system conserves water which is typically wasted by
users while waiting for warm water to flow from a hot water faucet.
The system provides a recirculating cooled hot water supply line
from the cooled-off end of a hot water line back to the hot water
heater of the hot water distribution system. The system is provided
with a plurality of control means to electrically energize the
system's recirculating pump so long as a pressure switch detects
that the main water supply is providing sufficient water pressure
to the system. In operation the recirculating pump opens a check
valve in the recirculating line and closes the check valve in the
main water supply line and recirculates the cooled hot water back
to the hot water heater for ultimate use. If the main water supply
has insufficient pressure, the recirculating cooled hot water
system is non-functional.
Basic HWR with a Pressure Switch Required to Activate, Based on
Incoming Water Pressure.
[0025] U.S. Pat. No. 5,829,475, issued Nov. 3, 1998 to Acker,
discloses an on-demand zone valve recirculation system. The zone
valve hot water recirculation system generally includes a hot water
source, such as an electric or gas water heater, a conduit for
enabling circulation of hot water from hot water source to one or
more plumbing fixtures and recovery of water to the hot water
source, a pump for accelerating delivery of hot water to the
fixtures and, importantly, a zone valve for preventing flow of
water into the hot water source during standby periods of the hot
water source. A controller, which may include an electronic timer,
is provided for causing the zone valve to open and close and the
pump to start and stop.
Demand Type System that Functions as an Inlet Booster Pushing Water
Towards the Fixture. It also Closes and Controls the HWR Line.
[0026] U.S. Pat. No. 4,750,472, issued Jun. 14, 1988 to Fazekas,
indicates a control means and process for domestic hot water
re-circulating system having a hot water supply pipe and a hot
water return pipe connected in a loop between a hot water outlet of
a hot water tank and a return inlet to that tank, and having an
electrically controlled recirculating pump in the loop, for keeping
sufficient circulation in the loop as to assure substantially
instant dispensing of water of a desirably high temperature. The
control governs the operability of the recirculating pump, causing
it to operate for a pre-established time period as determined by
the amount of time required to bring the supply pipe portion of the
recirculation loop up to desired maximum operating temperature.
After the supply pipe portion of the recirculation loop is brought
up to the desired maximum operating temperature, the control
switches off the recirculating pump for a pre-established time
period determined by the heat-holding capability of the supply side
of the recirculating loop, and the minimum desired operating
temperature of the supply portion of the recirculating loop.
Tank-Type HWR Based on Timing, NOT Temperature.
[0027] U.S. Pat. No. 1,780,379, issued Nov. 4, 1930 to Durdin, Jr.,
puts forth an automatically controlled hot water circulating
system. The hot water is supplied from the hot water tank or
reservoir through a supply pipe to the hot water faucets and then
is returned by way of a return pipe through a pump back to the hot
water reservoir. The pump is operated to circulate water from the
top or hot water side of the storage reservoir back to the bottom,
so that hot water is continuously available throughout the length
of the supply pipe.
Basic HWR with Boiler and Storage Tank. Does not Apply to Tankless
HWR.
[0028] U.S. Pat. No. 7,036,520, issued May 2, 2006 to Pearson, Jr.,
concerns a hot water heater recirculation system and method. The
hot water recirculation system includes a source of hot water, a
fixture, a fluid circuit, a fluid pump, and an electrical circuit
sensor. The fixture is remote from the source of hot water and is
configured to dispense hot water. The fluid circuit extends from
the source to the fixture for delivering hot water to the fixture.
The fluid circuit returns to the source for recirculating hot water
in the fluid circuit back to the source for reheating. The fluid
pump is configured for recirculating hot water through the fluid
circuit. The electrical circuit sensor is configured to detect
operation of an electrical circuit proximate the fixture and
associated with a user operating the fixture. The electrical
circuit sensor is further configured to initiate operation of the
fluid pump responsive to detected operation of the electrical
circuit to initiate hot water recirculation.
Tank Type HWR with Remote Activation Required (Motion Sensing)
[0029] U.S. Pat. No. 4,945,942, issued Aug. 7, 1990 to Lund,
illustrates an accelerated hot water delivery system for providing
hot water to a plurality of plumbing fixtures from a hot water
source. Flow switch means are provided to enable a pump to
circulate hot water to the plumbing fixtures in response to water
being withdrawn from a plumbing fixture. In addition, the hot water
source may include a hot water recovery apparatus for withdrawing
hot water from circulation pipes subsequent to cessation of water
flow from a plumbing fixture.
Flow Activated--Booster Type System
[0030] U.S. Pat. No. 4,936,289, issued Jun. 26, 1990 to Peterson,
is for a usage responsive hot water recirculation system. The
energy conservation apparatus controls the operation of a
recirculating hot water distribution system which comprises of a
hot water heater having an outlet and an inlet; a return pipe
interconnecting the end of the supply pipe back to a tee on the
makeup water inlet to form a loop; and an electrically operated
recirculating pump in the loop, usually on the return pipe, that
circulates the hot water around the loop. Thus hot water is
available anywhere in the system without having to first discharge
any cooled hot water that has been standing in the piping. The
invention consists of a sensitive flow sensor or usage detection
device located on the unheated makeup water supply and connected to
a controller. The controller turns on the recirculating pump only
when hot water is draw from any of the usage points. The invention
saves energy by reducing the heat loss from the hot water
distribution system. Options are available to prevent false
activation due to system leakage, to prevent activation on very
short usages, to turn off or prevent the activation of the system
if the distribution system is already hot, to run the pump for a
preset minimum time and/or to monitor leakage or sensor problems in
the system.
Not Basic HWR--Activated by Flow and Turns Off when CW Stops.
Demand/Booster Type
[0031] U.S. Pat. No. 4,628,902, issued Dec. 16, 1986 to Comber,
provides a hot water distribution system for providing almost
instantaneous supply of hot water at a hot water usage outlet. The
system of the invention comprises a closed loop and a pump
circulating hot water in the closed loop from a supply of hot water
and back to the supply of hot water. One or more usage outlets are
connected to the closed loop each by a relatively short length of
pipe. A one-way check valve prevents drawing water from the return
line of the closed loop. Heat insulation of the closed loop is
provided to prevent unnecessary heat losses, and a thermally
operated switch may be used to control the operation of the closed
loop circulation pump to maintain the water in the closed loop at a
predetermined temperature.
Basic Tank-Type HWR
[0032] U.S. Pat. No. 7,000,626, issued Feb. 21, 2006 to Cress,
shows an instantaneous and constant fluid delivery system and a
method and means for maintaining a constant supply of a fluid with
specific characteristics within a fluid supply conduit from a
supply source of the fluid with specific characteristics at a point
of service of the fluid with specific characteristics in which a
first open end of a recirculation conduit is located within the
fluid with specific characteristics supply conduit adjacent the
point of service. A second end of the recirculation conduit is
connected to pump means in such manner that a portion of the fluid
with specific characteristics within the fluid with specific
characteristics supply conduit adjacent the point of service is
constantly circulated back. In an alternate embodiment a similar
recirculation conduit is utilized in a manner to prevent freezing
of conduits in a total fluid supply line which includes portions in
relatively warm areas and in areas subject to freezing.
Domestic Pipe-In-Pipe Tempering System
[0033] U.S. Pat. No. 4,917,142, issued Apr. 17, 1990 to Laing,
claims a secondary circulation device for effecting secondary
circulation of water into a hot water tank not having a return
opening. The arms of a T-fitting are place in series with the
distribution line near the outlet port of the water tank. A return
line, continuous at one end with the distal portion of the
distribution line, is continuous at the other end with a relatively
small internal line which lies within the leg of the T-fitting, one
arm of the T-fitting, and extending through the outlet port into
the water tank. A relatively low power pump and a sinking-ball
valve are placed in series with the return line to cause the flow
of water in the secondary circulation system to flow in one
direction only.
Tank-Type HWR with Special Diverter Fitting
[0034] U.S. Pat. No. 5,735,291, issued Apr. 7, 1998 to Kaonohi,
describes a hot water re-circulating system for a building
comprising a water pump connected between an auxiliary water return
line extending from a hot water faucet to a remote hot water
heater. The water pump is controlled by a timer/switch located at
the hot water faucet, so that when the hot water faucet is opened,
hot water will come out therefrom. In a second embodiment, two
water pumps are each connected between two auxiliary water return
lines extending from two hot water faucets to a remote hot water
heater. Each water pump is controlled by a timer/switch located at
the hot water faucets, so that when the hot water faucets are
opened, hot water wall come out therefrom.
Direct Recirculation--Basic HWR with Remote Activation
Required.
[0035] U.S. Pat. No. 6,997,200, issued Feb. 14, 2006 to King,
discloses a water conservation system which recirculates and/or
recycles fluids normally lost down the drain during the time it
takes for a desired temperature to be attained for usage of the hot
fluids. A recirculating/recycling valve, through which hot fluids
may flow, has an additional port fitted to the valve body, which by
positioning the handle in a singularly unique position, fluids not
at the desired temperature are sent back to the source from which
they came, to a recycling toilet tank system or to a recycling
standpipe at atmospheric pressure.
This is a Hot and Cold Water Conservation System. Does not Apply to
Tankless HWR
[0036] U.S. Pat. No. 5,829,475, issued Nov. 3, 1998 to Acker,
indicates an on-demand zone valve recirculation system. The zone
valve hot water recirculation system generally includes a hot water
source, such as an electric or gas water heater, a conduit for
enabling circulation of hot water from hot water source to one or
more plumbing fixtures and recovery of water to the hot water
source, a pump for accelerating delivery of hot water to the
fixtures and, importantly, a zone valve for preventing flow of
water into the hot water source during standby periods of the hot
water source. A controller, which may include an electronic timer,
is provided for causing the zone valve to open and close and the
pump to start and stop.
Tank-Type Basic HWR with Zone Valve that Opens and Closes HWR to
Heat Source. Cannot be Used for Continuous Operation.
[0037] U.S. Pat. No. 7,077,155, issued Jul. 18, 2006 to Giammaria,
puts forth a hot water circulating system which provides instant
hot water including a hot water source connected to one or more
fixtures and a hot water return line from the fixture to the hot
water source including a check valve and a continuous circulation
pump in the return line.
Standard Tank-Type HWR
[0038] U.S. Pat. No. 5,941,275, issued Aug. 24, 1999 to Laing,
concerns a pump for periodic conveyance of the cooled-down water
content of a hot water distribution line. The hot water
distribution system incorporates a pump positioned close to, and
between each set of hot and cold water taps to which periodically
move the cooled-down water content of the hot water distribution
line through the cold water distribution line back to the hot water
tank until the total content of the hot water line has a
predetermined temperature. The pump is provided with a valve
responsive to pump-generated pressure to prevent backflow when the
pump is not in use and the pressure in the cold water distribution
line is lower than the pressure in the hot water distribution line,
such as when water is drawn through a cold water tap.
Demand Type System--Single Fixture--Hot/Cold Cross Connection
[0039] U.S. Pat. No. 4,142,515, issued Mar. 6, 1979 to Skaats,
illustrates a timed water recirculation system and apparatus for
effecting a timed recirculation of the hot water in a water
distribution network such as for an apartment complex. A
recirculating pump is responsive to a drop in pressure in the hot
water output line of a water heater and provides recirculation of
the water in the hot water lines from the remote apartment
locations for a timed interval. After the timed interval, and after
the system has returned to the starting pressure, the recirculating
pump is again ready for operation at the time of the next use of
the hot water in the system.
Timer Based and Pressure Sensitive HWR
[0040] U.S. Pat. No. 4,450,829, issued May 29, 1984 to Morita, is
for a water-saving hot water distribution system for a dwelling or
other building designed to avoid the waste of water incident to
letting the water run until hot water reaches an open hot water
faucet or valve. Adjacent each hot water outlet valve there is a
control unit having an inlet connected to a hot water supply line
from the water heater, a supply outlet connected to the hot water
faucet or valve and a return outlet connected by a return line to
an inlet of the water heater. Between the inlet and the supply
outlet of the control unit there is a normally closed valve which
is thermostatically controlled so as to open only when water in the
control unit is at or above a predetermined temperature. When a hot
water faucet or valve is opened and water in the hot water supply
line has cooled to a temperature below a predetermined value, the
control valve remains closed and water in the hot water supply line
is returned to the water heater by a circulating pump. When hot
water reaches the control unit, the control valve is
thermostatically opened so as to supply a full flow of hot water to
the faucet or outlet valve. The water circulating pump is then
turned off, thereby avoiding a waste of energy that would be
incident to continuous operation of the pump. Standard Tank-Type
HWR requiring control valve at each fixture.
[0041] Most of the prior art systems are very similar to each
other. Most are standard tank-type hot water recirculation systems.
Only a couple could be applied to tankless, but they are demand
type systems that predominately serve a single fixture or have
special controls or valves. Some of these require remote activation
or sensors. Some of these systems have similar components and
piping arrangements.
[0042] What is needed is the system of the present invention which
is engineered and designed to address the complications associated
with tankless water heaters and efficient hot water return. The
present invention utilizes the modulating burner of a tankless
heater to effectively and efficiently heat the return line, avoid
stand-by losses associated with tank-type water heaters and protect
the heat exchanger of the tankless heater. Furthermore, the present
invention is designed to operate without the use of auxiliary
sensors, activation and associated wiring. The invention is
designed to conserve water and fuel while providing instantaneous
hot water to every fixture group in conjunction with tankless water
heater installations. The present invention allows the use of
traditional hot water return, pump sizing and piping for tankless
water heating applications.
BRIEF SUMMARY OF THE INVENTION
[0043] The objective of the invention is to facilitate traditional
hot water return in tankless water heating systems and eliminate
the use of water storage tanks in potable domestic hot water
recirculation systems. This eliminates the need for additional
storage equipment in non storage applications, specifically
designed to operate with various flow and pressure sensitive
heating products such as tankless water heaters.
[0044] In brief, a tankless water heater hot water return system
allows the use of traditional hot water return, pump sizing and
piping methodology for tankless water heating applications. As
water circulates through the unit's hot water recirculation line,
the device senses that the system loop has fallen below the set
point. The device then allows water to pass though the device and
into the heat source heat exchanger. Once the system set point has
been satisfied, the device will turn off until another demand for
heating cycle. This is an energy efficient device due to low power
consumption, electronic start and stop, low heating requirements
and conservation of water.
[0045] The present invention is engineered to specifically
facilitate Hot Water Recirculation (HWR) in conjunction with
Tankless Water Heaters. The present system has been designed,
tested and is moving towards third Party Approval and
Manufacturing. The present system is a simple piping arrangement
with a Pump, Solenoid Valve and Electronic Temperature Control. An
alternate embodiment does not employ the Solenoid Valve.
[0046] The present invention is designed to facilitate hot water
recirculation in conjunction with tankless water heaters,
specifically addressing the major issues related to tankless hot
water return recirculation. The present invention inherently lends
itself to energy efficiency and water conservation.
[0047] The present invention differs from all prior art inventions
in several distinct ways: [0048] 1) The present system is
specifically designed to facilitate Whole House Hot Water
Recirculation with Modulating Tankless Waters Heaters. All other
systems have been designed around Tank-Type heaters and some have
been adapted for use with tankless heaters. [0049] 2) The system
pump of the present invention has been sized in accordance with
tankless heater requirements, flow rates and burner modulation.
[0050] 3) The system of the present invention protects the tankless
heater from direct recirculation HWR, which most of the prior art
systems employ. Direct recirculation in prior art systems reduces
and/or voids tankless heater warranties. [0051] 4) The system of
the present invention was designed to replace tank-type heaters
that are being used for tankless HWR. The tank-type units do not
reduce tankless warranties, but they have enormous energy costs
associated with their operation. [0052] 5) The system of the
present invention is temperature based and does not require any
external sensors, motion detectors, remote switches and associated
wiring. The system of the present invention is totally self
contained and pre-wired. [0053] 6) The system of the present
invention does not require timing controls, processors or pattern
trending. It is temperature based with a fully adjustable
differential for maximum energy efficiency. [0054] 7) The system of
the present invention is designed to operate with either continuous
or intermittent HWR Pump. [0055] 8) The system of the present
invention is a true, traditional HWR system that does not waste
energy by heating the cold water supply. Some of these other
systems utilize the cold water line, in lieu of a separate HWR
line. This method is unnecessarily heating the cold water supply
and wasting energy.
[0056] The Tankless Return Solution Hot Water Return System of the
present invention is design engineered to address and to correct
tankless water heating systems utilizing hot water recirculation.
The invention addresses all of the outstanding issues that result
from piping tankless water heaters with hot water
recirculation.
[0057] The present invention allows the user the ability to pipe
tankless water heaters with traditional recirculation. It
eliminates the head losses associated with tankless heat exchangers
and allows the user to utilize a small, fractional horsepower pump,
further saving energy during operation.
[0058] The present invention utilizes the modulating burner of the
tankless heater to only use the amount of fuel necessary to heat
the return line.
[0059] The present invention forces circulation through the
tankless heater only when heat is required. The present invention
by-passes the tankless heater when not heating the return line.
This prevents reduction of warranty as constant or direct
circulation is not employed.
[0060] The present invention uses built-in temperature sensing with
adjustable differential to maximize efficiency. The invention does
not require any external sensors or activation. The invention works
in conjunction with a timer to reduce wasted energy in non-use
periods.
[0061] The present invention eliminates the use of tank-type water
heaters as the recirculation heat source. A typical hot water
return line in a residential application requires approximately
5,000 BTU per hour to maintain a 10.degree. F. temperature
differential. Small electric tank-type water heaters only have an
input of 5118 BTU per hour at 1.5 KW. This means that as long as
there is circulation, the electric water heater element will be on,
trying to maintain temperature. The present invention efficiently
and effectively heats the hot water return line with the tankless
heater which has much greater input (199,999 BTU per hour). The
invention also eliminates the stand-by losses associated with
tank-type water heaters.
[0062] The present invention is designed to operate a whole-house
or whole-building recirculation. It services all fixture groups
within a building, not just a single fixture group. The invention
provides instantaneous hot water at every fixture. Many state
building codes such as the Florida Building Code require hot water
recirculation on any piping system exceeding 100 feet in length.
The invention allows users of tankless water heaters to efficiently
employ hot water recirculation without the negative impacts of
wasted energy, reduced warranties and single fixture, point of use
recirculation. The invention returns heated water back to the
tankless heater instead of dumping it into the cold water line,
where it will be utilized, rather than creating more heat loss by
injecting heated water into uninsulated cold water piping.
[0063] The present invention is designed to use the least possible
amount of electricity to operate. The invention uses only 175 watts
of energy in full operation and less than 100 milliamps of power in
stand-by mode. Electrical energy is more expensive to operate than
natural or LP gas.
[0064] The present invention uses the quick recovery of the gas
fired tankless heater to conserve energy and to effectively heat
the return line.
[0065] Heat losses through circulation and radiation can be
controlled by avoiding constant circulation and through insulation
of hot water piping. As mentioned above, many state building codes
also require hot water lines to be insulated if they exceed 100
feet in length. It is good practice to insulate all hot water lines
to avoid heat loss. The use of timers on recirculation systems is
always recommended to maximize energy savings. The invention is
designed to provide cost-effective and energy efficient hot water
recirculation for tankless water heaters.
[0066] Water conservation is an extremely important issue today.
Millions of gallons of fresh water are wasted each year by systems
that do not employ some type of hot water recirculation. The US DOE
estimates that an average family of four can yearly waste over
10,000 gallons of water down the drain just waiting for hot water
to arrive at the point of use. The energy consumed by maintaining a
recirculation system is easily offset by water and sewer charges.
But this only is true if an energy efficient system such as the
presented invention is employed. A tank-type water heater used for
recirculation with a tankless heater has energy costs greater than
a tank-type water heater operating stand-alone.
[0067] The present invention resolves complications that are
experienced when utilizing hot water return recirculation in
conjunction with tankless water heaters. These issues specifically
addressed by the invention are: Reduction of tankless warranties
due to Direct Recirculation, Use of Tank-Type Storage Water Heaters
for Tankless Hot Water Return and Single Fixture Group
Recirculation requiring activation, associated sensors, switches
and wiring.
[0068] The present invention exclusively resolves each and every
issue currently affecting tankless hot water return systems. There
are various methods that have been adapted to assist tankless hot
water return, but these methods and systems do not resolve each and
every outstanding issue.
[0069] The present invention provides a design engineered, packaged
piping system comprising: [0070] Copper or CPVC Tubing [0071]
Non-Ferrous Fittings [0072] Check Valves [0073] Solenoid Valve(s)
[0074] Bronze Heating Pump(s) [0075] Electronic Temperature Control
[0076] Piping By-Pass for heater protection [0077] Built-In
Temperature Sensing
[0078] The present invention provides system sizing of the heating
pump and solenoid valve to provide an acceptable flow rate during
heating cycles.
[0079] The present invention incorporates the following
features:
[0080] By-Pass of all return water flow away from the tankless
heater in stand-by (off) mode.
[0081] Utilization of the modulating burner of the tankless heater
and use of the tankless heater as the hot water return heat
source.
[0082] Compensation for tankless heat exchanger head losses to
provide traditional whole-house and whole-building hot water return
recirculation for tankless water heaters.
[0083] Built-In Temperature Control and Sensing that does not
require external controls, switches, sensors, timing mechanisms or
remote activation.
[0084] Pump Delay Relay for controlling the system hot water return
pump.
[0085] Energy Efficient design to use a minimal amount of energy to
operate.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0086] These and other details of my invention will be described in
connection with the accompanying drawings, which are furnished only
by way of illustration and not in limitation of the invention, and
in which drawings:
[0087] FIG. 1 is a diagrammatic plan view of the layout of the
piping arrangement and location of each component of the present
invention showing how the present invention is configured with
specific fittings and component locations;
[0088] FIG. 2 is a diagrammatic piping diagram and an explanation
of how the invention operates in full heating mode. This mode is
active when the system is calling for heat in the hot water return
line. This drawing indicates how the invention is piped into the
tankless heater and system hot water supply and return;
[0089] FIG. 3 is a piping diagram and an explanation of how the
invention operates in the stand-by mode, when there is no call for
heat in the hot water return line. This drawing indicates how the
invention is piped into the tankless heater and system hot water
supply and return;
[0090] FIG. 4 is a Sequence of Operation and corresponding wiring
diagram for the invention. This written sequence of operation
explains exactly how the invention operates electrically and
mechanically from the time that power applied until the system
temperature is satisfied. The sequence of operation describes how
the Electronic Temperature Control switches power to turn the
system on and off.
DETAILED DESCRIPTION OF THE INVENTION
[0091] In FIGS. 1-4, a tankless hot water return recirculation
system 20 (indicated by dashed rectangle in FIGS. 1-3) is
integrated into a tankless hot water distribution heater 30 and
pipe array.
[0092] The hot water return recirculation system 20 is alternately
connected to and isolated from the tankless hot water heater 30
having a cold water feed pipe 16 and a hot water distribution
pipeline 5. The hot water return recirculation system 20 comprises
a recirculation pipeline 15 connecting between the hot water
distribution pipeline 5 and the tankless hot water heater 30 for
pumping previously heated warm water from the hot water
distribution pipeline 5 back through the recirculation pipeline 15
to the tankless hot water heater 30 for reheating the warm water in
the hot water heater to send the reheated water back through the
hot water distribution pipeline for use. Means for opening and
closing a pipeline connection between the hot water distribution
pipeline and the water recirculation pipeline, which may comprise a
normally closed solenoid valve 9 in the recirculation pipeline
which opens to admit heated water from the hot water distribution
pipeline 5 into the water recirculation pipeline 15 or closes to
bypass the heater 30. Means for opening and closing a pipeline
connection between the recirculation system and the tankless hot
water heater, which may comprise a recirculation to heater by-pass
valve 11 cooperating with means for opening and closing the return
water feed pipeline connection to the tankless hot water heater. An
inline water recirculation pump 10 pumps the warm water from the
hot water distribution pipeline 5 to the tankless water heater
30.
[0093] A temperature sensor 3 with a temperature indicator 2 is
positioned in a brass dry well 4 in the hot water distribution
pipeline 5. A two stage electronic temperature control 2
communicates with the temperature sensor 3, the recirculation pump
10, and the means for opening and closing the pipeline connections
9 and 11 to activate the recirculation pump 10 to activate a flow
of warm water from the hot water distribution pipeline 5 to the
tankless hot water heater 30 for heating the warm water when the
warm water in the hot water distribution pipeline reaches a low set
temperature and to deactivate the recirculation pump 10 and switch
back the means for opening and closing pipeline connections 9 and
11 when the water temperature reaches a set high temperature to
isolate the hot water return recirculation system 15 from the
tankless hot water heater 30 and the hot water distribution
pipeline 5.
[0094] A normally partially open recirculation pump valve 12 in the
recirculation pipeline 15 acts as a water prime to the
recirculation pump 10 and serves as a secondary by-pass line in the
event of the solenoid valve 9 failure.
[0095] A normally open cold water supply pipe 33 feeds the tankless
hot water heater 30.
[0096] The hot water pipelines 5 and 15 preferably further comprise
an outer layer of thermal insulation to minimize radiation heat
loss therefrom.
[0097] The recirculation pump 10 of the present invention is
structured to function in accordance with the tankless water heater
30 requirements, flow rates and hot water heating modulation.
[0098] The hot water return recirculation system 20 is configured
for whole house hot water recirculation with modulating tankless
water heaters 30. The hot water return recirculation system 20
protects the tankless water heater 30 from direct recirculation
from the hot water distribution pipeline 5.
[0099] The hot water return recirculation system 20 is configured
to operate with either a continuous hot water return pump or an
intermittent hot water return pump.
[0100] The hot water return recirculation system 20 is connected to
the modulating burner of the tankless water heater 30 for use of
the tankless water heater as a hot water return heat source.
[0101] The hot water return recirculation system 20 is connected to
a tankless water heater 30 with a traditional hot water return. The
hot water return recirculation system 20 of the present invention
compensates for the head losses of the tankless heater to allow for
whole-house and whole-building hot water return.
[0102] In use in FIG. 1, the drawing depicts the invention's layout
of components and their respective locations. The hot water return
recirculation system of the present invention is a piping
arrangement constructed of CPVC or Copper Tubing with elbow and tee
fittings as shown on the FIG. 1 drawing.
[0103] The system comprises a 120 Volt Pug-In Cord 1 and an
Electronic Temperature Control 2 with two stages of control. The
first stage controls the hot water return recirculation system of
the present invention and the second stage controls an external hot
water return pump in the tankless water heater hot water
distribution pipeline. The Electronic Temperature control 2 has a
remote temperature sensor wire and sensing bulb 3. The Sensing Bulb
3 is in located in Brass Dry Well 4. The Brass Dry Well 4 is
immersed in the Lower By-Pass Pipe 5 of the hot water distribution
pipeline to sense system return temperature.
[0104] A lower hot water return by-pass valve 6 is located on the
lower by-pass pipe 5 of the hot water distribution pipeline for
servicing of the invention. A hot water return check valve 7 is
located on the lower by-pass pipe 5 to insure that flow can only be
directed in one direction, away from the hot water return
recirculation system and the tankless heater.
[0105] A system check valve 8 allows for flow from a tankless
heating source in one direction, to mix flow with the return water
that is flowing through the lower by-pass pipe 5. In a stand-by
(off) mode there is no other flow through the invention.
[0106] Upon a call for heating of the return line, as sensed by the
sensing bulb 3 of the electronic temperature control 2, the
invention is activated for heating of the hot water return line.
The electronic temperature control 2 switches power to the Solenoid
Valve 9 and to the Heating Pump 10 simultaneously. The system check
valve 11 only allows flow towards the tankless heating source and
prevents any backflow of cold water.
[0107] The Upper Heating Pump Fill Valve 12 is provided for water
prime to the Heating Pump 10 and also functions as a secondary
by-pass line in the event of Solenoid Valve 9 failure.
[0108] An Aquastat Relay two stage electronic temperature control 2
is preferably provided to allow for starting and stopping the
system hot water return pump based on return temperature.
[0109] In reference to FIG. 2, the drawing is a piping diagram and
an explanation of how the invention operates in full heating mode.
This mode is active when the system is calling for heat in the hot
water return line. This drawing indicates how the invention is
piped into the tankless heater and system hot water supply and
return.
[0110] Power is applied through 120 Volt Pug-In Cord 1. Electronic
Temperature Control 2 and Temperature Sensor 3 senses hot water
return temperature. The system Hot Water Return Pump 10 is
circulating water from the system supply to the system return
piping either continuously or intermittently.
[0111] If the hot water return temperature is 10.degree. F. below
the Electronic Temperature Control 2 setpoint, the invention is
activated for heating of the hot water supply and return piping.
The electronic temperature control 2 is accurate to .+-.1.degree.
F. The electronic temperature control 2 switches power to activate
the Solenoid Valve 9 and the Heating Pump 10. The Solenoid Valve 9
opens and the Heating Pump 10 begins to circulate water towards the
inlet of the tankless heater 30.
[0112] The tankless heater 30 begins to heat the flowing water and
discharges the heated water back into the system supply pipe 5. The
heated water is recirculated from the farthest fixture group 35
back to the hot water return connection of the invention 15. The
system hot water return pump 31 continues to circulate the heated
water around the hot water loop 5. The hot water return check valve
7 and the system check valves 8 and 11 only allow flow in one
direction, preventing stray flow or backflow from the cold water
inlet piping 33.
[0113] The Lower By-Pass Valve 6 is normally in the full open
position and is provided for servicing of the invention.
[0114] The Upper Heating Pump Fill Valve 12 is normally partially
open to provide water prime to the Heating Pump 10. The upper
heating pump fill valve 12 also functions as a full by-pass in the
event of Solenoid Valve 9 failure.
[0115] In reference to FIG. 3, the drawing is a piping diagram and
an explanation of how the invention operates in By-Pass or Off
Mode. This mode is active when the system has satisfied the call
for heat in the hot water return line. This drawing indicates how
the invention is piped into the tankless heater and system hot
water supply and return.
[0116] Power is applied through 120 Volt Pug-In Cord 1. Electronic
Temperature Control 2 and Temperature Sensor 3 senses hot water
return temperature. The system Hot Water Return Pump 31 is
circulating water from the system supply to the system return
piping either continuously or intermittently.
[0117] If the hot water return temperature is within 10.degree. F.
of the Electronic Temperature Control 2 set point, the invention is
deactivated for heating of the hot water supply and return piping.
The electronic temperature control 2 is accurate to .+-.1.degree.
F. The electronic temperature control 2 disconnects power to the
Solenoid Valve 9 and the Heating Pump 10. The Solenoid Valve 9
closes and the Heating Pump 10 turns off to stop circulation water
towards the inlet of the tankless heater 30.
[0118] The heated water is recirculated from the farthest fixture
group 35 back to the hot water return connection of the invention
15. The system hot water return pump 31 continues to circulate the
heated water around the hot water loop 5. The hot water return
check valve 7 and the system check valves 8 and 11 will only allow
flow in one direction, preventing stray flow or backflow from the
cold water inlet piping 33.
[0119] The Lower By-Pass Valve 6 is normally in the full open
position and is provided for servicing of the invention.
[0120] The Upper Heating Pump Fill Valve 12 is normally partially
open to provide water prime to the Heating Pump 10. The upper
heating pump fill valve 12 also functions as a full by-pass in the
event of Solenoid Valve 9 failure.
[0121] In reference to FIG. 4, the drawing is a Sequence of
Operation and corresponding wiring diagram for the invention. This
written sequence of operation explains exactly how the invention
operates electrically and mechanically from the time that power
applied until the system temperature is satisfied. The sequence of
operation describes how the Electronic Temperature Control switches
power to turn the system on and off.
[0122] The system Hot Water Return Pump 1 is On for continuous
operation or Off for Pump Delay Relay.
[0123] 120 Volt Power is applied through Plug-In Cord 2.
[0124] Electronic Temperature Control Sensor 3 reads a low return
water temperature of 105.degree. F. or less.
[0125] Electronic Temperature Control 2 energizes NO Contact on
Stage 2 at 105.degree. F. to start System Hot Water Return Pump
10.
[0126] For Pump Delay Interlock, Stage 2 of the electronic
temperature control 2 switches external incoming 120 Volt Hot
Supply from C.
[0127] Contact to NO Contact to power external Hot Water Return
Pump 10.
[0128] Electronic Temperature Control Sensor 2 reads a low return
water temperature of 100.degree. F. or less.
[0129] Electronic Temperature Control 2 switches 120 Volt power
from C Contact to NO Contact on Stage 1.
[0130] Electronic Temperature Control 2 switches power to start
Heating Pump 10 and Solenoid Valve 9.
[0131] Electronic Temperature Control 2 senses high return water
temperature of 110.degree. F. or higher.
[0132] Electronic Temperature Control 2 disconnects power at Stage
2 at 110.degree. F.
[0133] Heating Pump 10 and Solenoid Valve 9 are de-energized and
close off flow through the tankless heater.
[0134] Electronic Temperature Control 2 senses a high return water
temperature of 115.degree. F. or higher.
[0135] Electronic Temperature Control 2 de-energizes NO Contact on
Stage 2 at 115.degree. F.
[0136] Hot Water Return Pump 10 is deactivated.
[0137] Hot Water Return Pump Cycle repeats when temperature falls
to 105.degree. F.
[0138] Heating Cycle of hot water return line repeats when
temperature falls to 100.degree. F.
[0139] In use, the premium Tankless Water Heater Hot Water Return
System 20 of the present invention allows the use of traditional
hot water return, pump sizing and piping methodology for tankless
water heating applications. The system senses the temperature of
recirculated water in the system loop, allowing for operation of
the tankless or heat source when system loop falls below a certain
set point.
[0140] The premium tankless water heater hot water return system of
the present invention is fabricated of a pre-piped, enclosed
assembly containing: [0141] Solenoid Control Valve 9; [0142] Piping
15; [0143] Water pump 10; [0144] Operator and Hot Water Return
Aquastat 2; [0145] Valves 9, 11, 12; [0146] Fittings.
[0147] The components work together accordingly: As the aquastat
senses the loop temperature falling, it drives a water pump to
allow water to reach and activate the heating source. Once the heat
source has satisfied the demand for hot water, the aquastat senses
the set point and de-energizes the device. The unit will not allow
system loop water to continue through the heating source.
[0148] The device may be structured so that the addition or
elimination of certain parts may achieve similar results.
[0149] The invention may be used in either domestic or commercial
application of potable or non potable water, utilizing many heat
sources.
[0150] An ECONOMY Tankless Water Heater Hot Water Return System
allows the use of traditional hot water return, pump sizing and
piping methodology for tankless water heating applications. The
system senses the temperature of recirculated water in the system
loop, allowing for operation of the tankless or heat source when
system loop falls below a certain set point.
[0151] The ECONOMY tankless water heater hot water return system of
the present invention is fabricated of a pre-piped, enclosed
assembly containing: [0152] Piping 15; [0153] Water pump 10; [0154]
Operator and Hot Water Return Aquastat 2; [0155] Valves 9, 11, 12;
[0156] Fittings.
[0157] The components work together accordingly: As the aquastat
senses the loop temperature falling, it drives a water pump to
allow water to reach and activate the heating source. Once the heat
source has satisfied the demand for hot water, the aquastat senses
the set point and de-energizes the device. The unit will not allow
system loop water to continue through the heating source.
[0158] The device may be structured so that the addition or
elimination of certain parts may achieve similar results.
[0159] The invention may be used in either domestic or commercial
application of potable or non potable water, utilizing many heat
sources.
[0160] The invention presented specifically addresses the use of
Traditional Hot Water Return Recirculation with Tankless Water
Heaters. Its use is not limited to Tankless Hot Water Return as its
design lends itself to various heating circulating uses. These uses
include, but are not limited to: Solar, Hydro Heating, Combination
Heating, Indirect Storage Heaters and various other applications
that require heat exchange.
[0161] Furthermore, the present invention creates a new method to
correctly pipe tankless water heaters with a hot water return
system. The present invention may be capable of achieving similar
results with the addition or elimination of certain components. Any
and all modifications or variations of this method or system should
be viewed as within the scope of the presented invention.
[0162] It is understood that the preceding description is given
merely by way of illustration and not in limitation of the
invention and that various modifications may be made thereto
without departing from the spirit of the invention as claimed.
* * * * *