Commercial Hot Water Control Systems

Abstract

A commercial hot water system includes a hot water source, and a hot water delivery line connected between the hot water source and at least one plumbing fixture. A pump, enables circulation of hot water to and from the fixtures. A controller provides for turning on the pump in conjunction with an external signal, and a detector, preferably a temperature sensor, in conjunction with the controller, is effective in stopping the pump to prevent heated water from being circulated.

Description

This application is a continuation-in-part of U.S. Patent application Ser. No. 12/641,236, filed Dec. 17, 2009, which is hereby incorporated by reference herein in its entirety.

The present invention is generally directed to plumbing systems and more particularly directed to commercial plumbing systems with energy saving recirculation of water.

In large buildings, such as, for example, apartment buildings, hotels, motels, and other commercial buildings, the boiler, or hot water supply, is disposed remotely to the point of use of hot water. Accordingly, if the water in the piping system has cooled, a user may have to run the water for an extended period of time in order to get hot water to a fixture.

In this case, water is wasted because the cooled water in the pipes is typically discharged into a drain during a period of time waiting for the arrival of hot water. Energy is also wasted because the discharged water was heated previously by the boiler.

This problem of both water waste and inconvenience has been solved by providing hot water recirculation systems which are installed in commercial buildings. Continuous circulation of hot water around the loop is quickly available at various points of use throughout the building. Most often, an electrically driven pump is installed at an end of a return line which draws hot water from the supply side of the boiler and returns it to the cold water inlet of the hot water supply.

This type of system enables quick access to hot water and, in fact, saves water; however, it is wasteful from an energy conservation point of view.

Even when insulated, recirculation pipes have a high heat loss. Accordingly, the heat loss from a continuously operating recirculation system can be quite high.

In order to conserve energy, systems may be configured to turn off the recirculation pump at specific times. This may be affected through a time clock which operates recirculation pump during the day and turns the pipe off at night.

While this system will reduce the heat loss at night, it has a severe drawback because recirculation is actually needed most during the evening. That is, during the day in an apartment building or hotel/motel, people will often use hot water at a number of fixtures throughout the building. This water draw keeps water in the distribution system thereby providing hot water quickly.

However, at night, very little hot water use occurs. When a person uses hot water at night, without operation of the recirculation pump a long time may be necessary for hot water to arrive at a remote fixture.

Accordingly, a system is desirable which enables the continuous, or sporadic, use of recirculation to maximize efficiency of this system, depending on the users' requirements. The present invention solves that problem.

SUMMARY OF THE INVENTION

A hot water delivery system in accordance with the present invention generally includes a boiler having a storage tank interconnected therewith and hot water delivery lines connected between the storage tank and at least one plumbing fixture. A cold water delivery line is provided and connected between the plumbing fixture and a cold water source and the boiler for delivering cold water thereto.

A pump is provided which is interconnected between the boiler and the storage tank, for circulation of the water from the storage tank to the fixture and return to the storage tank. A controller causes the pump to circulate water.

A temperature sensor, connected to the control system, is provided for causing the controller to stop the pump to prevent heated water from being circulated; a timer may be connected to the controller to turn on the pump. Alternatively, the pump may be turned on by the controller using any of various ways, such as through use of a switch or button, or automatically by use of, for example, a flow detector installed in the hot water line, or opening a hot water faucet.

BRIEF DESCRIPTION OF THE DRAWINGS

The advantages and features of the present invention will appear from the following description when considered in conjunction with the accompanying drawing, in which:

FIG. 1 is a flow diagram of a plumbing system 10 in accordance with the present invention for a commercial establishment, such as an apartment building, generally showing a boiler and conduits, in communication with at least one plumbing fixture, along with a pump, flow switch, controller, and timer.

DETAILED DESCRIPTION OF THE DRAWINGS

Referring to FIG. 1, there is shown a hot water recovery system 10 for a building 14 which generally includes a boiler 18, connected to a storage tank 22, and supplied by a feed line 24. A hot water delivery line 28 connecting the tank 22 with a plurality of plumbing fixtures 32 that are dispersed throughout the building 14. Also provided is a cold water delivery line 36 interconnecting the fixtures 32 with a cold water line 36 which is also interconnected with the boiler 18.

A pump 46 is connected between the boiler 18 and storage tank 22 for circulation of water to and from the fixture 32 in order to provide “instant” hot water at the fixtures and a controller 50 provides for switching electrical current from an outlet 52 to the pump 46 in order to cause the pump 46 to circulate water from the storage tank 22 to the fixture 32.

A detector, such as a temperature sensor, sound detection sensor, or flow detector, 56 may be disposed in a line 54 interconnecting the pump 46 with the storage tank 22 and causes the controller 50 to stop the pump 46 to prevent heated water from being circulated. Preferably the detector 56 is a temperature sensor, which may be a thermistor type of detector strapped to the outside of the line 54.

If the detector is a temperature sensor 56 is preferably configured for use with the controller for detecting a temperature increase, or gradient in the line over a relatively short preset period of time, for example, over a time value from about 5 seconds to about 15 minutes. The temperature increase may also be preset to detect a change during the preset time period of, for example, one or two degrees or more, and in response thereto causing the control system 52 to stop the pump 46. Thus, no matter what the actual temperature of the water in the line 54 is, an increase of, for example, one or two degrees will cause the pump 46 to stop. The pump may be turned on by the controller using any of various ways, such as through use of a switch or button, a flow sensor or temperature drop, sound detection sensor, or opening a hot water fitting. Preferably, a timer 64 may be incorporated into the controller 50 for causing the controller 50 to turn on the pump 46 at preset times. Preferably, the pump is stopped by the controller 50 receiving information through the temperature sensor 56.

Although the timer 64 is shown incorporated into the controller 50 if present it may be disposed anywhere in the system.

Although there has been hereinabove described a specific commercial hot water system in accordance with the present invention for the purpose of illustrating the manner in which the invention may be used to advantage, it should be appreciated that the invention is not limited thereto. That is, the present invention may suitably comprise, consist of, or consist essentially of the recited elements. Further, the invention illustratively disclosed herein suitably may be practiced in the absence of any element which is not specifically disclosed herein. Accordingly, any and all modifications, variations or equivalent arrangements which may occur to those skilled in the art, should be considered to be within the scope of the present invention as defined in the appended claims.

Claims

1. A hot water recovery system comprising:

a) a feed line supplying cold water to a boiler;

b) a hot water delivery line circulating hot water directly or indirectly from said boiler to one or more plumbing fixture dispersed throughout a building, and returning unused water;

c) a pump circulating water in a closed loop directly or indirectly from said boiler to said plumbing fixture and returning unused water from said fixture;

d) a controller, for turning on the pump in accordance with an external signal, and turning off the pump in accordance with information received from a detector, connected thereto and disposed in a water line, indicating a decreased use of hot water.

2. The hot water recovery system of claim 1 wherein said detector is a temperature sensor, and said temperature sensor and controller are configured to detect a selected temperature increase and in response thereto cause the controller to turn off the pump to prevent heated water from being circulated.

3. The hot water recovery system of claim 1 wherein said temperature increase is from about one to about two degrees F.

4. The hot water recovery system of claim 1 comprising a hot water storage tank fluidly connected between said boiler and said at least one plumbing fixture.

5. The hot water system of claim 2 wherein a timer, connected to said controller, causes said controller to turn on said pump at a present time.

6. A method of controlling the circulation of hot water in a building comprising:

a) receiving cold water from a cold water source through a feed line;

b) heating said hot water;

c) circulating said hot water through a hot water line in a closed loop to and from one or more plumbing fixture using a pump;

d) turning the pump on or off using a controller according to hot water demand;

wherein said controller is connected to a detector disposed in said hot water line and turns off said pump when it receives a first signal from said detector indicating a lack of hot water demand, said pump is turned on when said controller receives a second signal indicating a demand for hot water.

7. The method of claim 6 wherein said heating step comprises directing water into a boiler.

8. The method of claim 6 wherein said second signal is generated by a timer connected to said controller.

9. The method of claim 6 wherein said first signal is received from a detector disposed in said hot water line.

10. The method of claim 7 wherein said detector is a temperature sensor and said controller shuts down the pump when a temperature increase in said hot water line is detected.

11. The method of claim 10 wherein said temperature increase is from about 1 to about 2 degrees F.

12. The method of claim 8 wherein said first signal is received from a detector disposed in said hot water line.

13. The method of claim 7 wherein said detector is a temperature sensor and said controller shuts down the pump when a temperature increase in said hot water line is detected.

14. The method of claim 12 wherein said temperature increase is from about 1 to about 2 degrees F.