Water heater and control method therefor

• US 9,182,159 B2
• Filed: 10/14/2010
• Issued: 11/10/2015
• Est. Priority Date: 10/14/2010
• Status: Active Grant

• Current Assignee: Purpose Co., Ltd.
• Original Assignee: Purpose Co., Ltd.
• Inventors: Hatada, Yasutaka, Nakagawa, Kazuhiko, Naitoh, Katumi
• Primary Examiner(s): Huson, Gregory
• Assistant Examiner(s): NAMAY, DANIEL ELLIOT
• Application Number:
  US12/904,262
• Publication Number:
  US 20120090341A1
• Time in Patent Office: 1,853 Days
• Field of Search: 237/8.A, 237/8.C, 237/12, 237/2.A, 237/19, 237/57, 237/59, 237/62, 237/63, 237/81, 122/31.1, 122/32, 122/15.1, 122/18.1, 236/20.R, 236/25.R
• US Class Current: 1/1
• CPC Class Codes: B01B 1/00 Boiling; Boiling apparatus for physical or chemical purposes ; Evaporation in general
• CPC Class Codes: F24D 17/0026 with conventional heating means F24D17/0036 takes precedence
• CPC Class Codes: F24D 17/0078 Recirculation systems
• CPC Class Codes: F24D 17/02 using heat pumps
• CPC Class Codes: F24D 19/1051 for domestic hot water
• CPC Class Codes: F24D 2200/043 More than one gas or oil fired boiler
• CPC Class Codes: F24D 2200/12 Heat pump
• CPC Class Codes: F24D 3/08 in combination with systems for domestic hot-water supply
• CPC Class Codes: F24H 15/136 Defrosting or de-icing; Preventing freezing
• CPC Class Codes: F24H 15/175 where the difference between the measured temperature and a set temperature is kept under a predetermined value
• CPC Class Codes: F24H 15/215 before heating
• CPC Class Codes: F24H 15/219 after heating
• CPC Class Codes: F24H 15/238 Flow rate
• CPC Class Codes: F24H 15/25 Temperature of the heat-generating means in the heater
• CPC Class Codes: F24H 15/258 Outdoor temperature
• CPC Class Codes: F24H 15/269 Time, e.g. hour or date
• CPC Class Codes: F24H 15/281 Input from user
• CPC Class Codes: F24H 15/31 of valves having only one inlet port and one outlet port, e.g. flow rate regulating valves
• CPC Class Codes: F24H 15/325 of by-pass valves
• CPC Class Codes: F24H 15/335 Control of pumps, e.g. on-off control control of compressors of heat pumps F24H15/38
• CPC Class Codes: F24H 15/345 : Control of fans, e.g. on-off control control of fans of heat pump units F24H15/375
• CPC Class Codes: F24H 15/36 : of burners
• CPC Class Codes: F24H 15/395 : Information to users, e.g. alarms
• CPC Class Codes: F24H 15/421 : using pre-stored data
• CPC Class Codes: F24H 15/45 : remotely accessible
• CPC Class Codes: F24H 15/486 : using timers
• CPC Class Codes: F24H 8/00 : Fluid heaters characterised by means for extracting latent heat from flue gases by means of condensation
• CPC Class Codes: F25B 27/00 : Machines, plants or systems, using particular sources of energy F25B30/06 takes precedence
• CPC Class Codes: Y02B 30/00 : Energy efficient heating, ventilation or air conditioning [HVAC]

Abstract

A water heater includes one or a plurality of heat pumps that heat tap water or return water from a hot water supply part, a circulation line that supplies hot water heated in the heat pumps to the hot water supply part, and introduces the return water from the hot water supply part to the heat pumps, an incoming water pipe that joins to between the hot water supply part in the circulation line and the heat pumps and supplies the tap water, a circulation pump that returns the return water to the heat pumps and circulates the return water through the circulation line, and a control unit that controls operation or stop of the circulation pump according to driving operation time or elapsed stop time by linking a combustion process of the heat pumps.

Claims

1. A water heater comprising:

one or a plurality of heat exchangers that heat tap water or return water with combustion heat generated by combustion of a burner, the return water being from a hot water supply part;

a circulation line that supplies the tap water or the return water, which is heated by the heat exchangers, to the hot water supply part, and circulates the return water from the hot water supply part through the heat exchangers;

an incoming water pipe that joins the circulation line between the hot water supply part and the heat exchangers, and supplies the tap water to the circulation line;

a circulation pump that circulates the return water through the circulation line; and

a control unit that links the combustion of the burner to operation of the circulation pump, calculates a flow rate for supplying the hot water required for a thermal process after a predetermined time has passed since hot water supply had been ended by shut-off of an opening and shutting faucet that is set on the circulation line, starts the operation of the circulation pump and the combustion of the burner, the combustion corresponding to a quantity of heat for making the return water, which flows at the flow rate, a predetermined temperature, and stops the operation of the circulation pump and the combustion of the burner when a predetermined time of the thermal process has passed.

2. The water heater of claim 1, further comprising:

a temperature sensor that detects temperature of the tap water and/or the return water at an inlet part of the heat exchangers; and

a flow rate sensor that detects flow rates of the tap water and/or the return water for the heat exchangers in the circulation line,

wherein the control unit calculates required quantity of heat based on an incoming flow rate for the heat exchangers and temperature detected by the temperature sensor, stops combustion of the heat exchangers based on the required quantity of heat, and stops the circulation pump.

3. The water heater of claim 1, wherein the control unit further causes the circulation pump to operate when the flow rate in the circulation line is a predetermined value or over or when the required quantity of heat of the tap water and/or the return water is a predetermined value or over, during the stop of the circulation pump.

4. The water heater of claim 1,

wherein the circulation line includes

a hot water supply pipe that supplies hot water from the heat exchangers to the hot water supply part;

a return pipe that returns the return water from the hot water supply part to the heat exchangers; and

a branch that joins the incoming water pipe to the return pipe, and makes the tap water join the return pipe, and

wherein the circulation pump is disposed on the return pipe.

5. The water heater of claim 4, wherein a check valve that prevents a back flow of the tap water or the return water is provided on the incoming water pipe and the return pipe.

6. The water heater of claim 1, wherein the control unit causes the circulation pump to move to freezing prevention operation when hot water temperature in the circulation line is predetermined value or below.

7. The water heater of claim 6, wherein the control unit includes a control switch for controlling operation for the circulation pump, and causes the circulation pump to execute the freezing prevention operation according to setting of the control switch.

8. A water heating control method, comprising:

heating tap water or return water by one or a plurality of heat exchangers with combustion heat generated by combustion of a burner, the return water being from a hot water supply part;

supplying the tap water or the return water, which is heated by the heat exchangers, to the hot water supply part, and circulating the return water from the hot water supply part through the heat exchangers via a circulation line by a circulation pump;

supplying the tap water to the circulation line by joining the tap water to the circulation line between the hot water supply part and the heat exchangers; and

linking the combustion of the burner to operation of the circulation pump, calculating a flow rate for supplying the hot water required for a thermal process after a predetermined time has passed since hot water supply had been ended by shut-off of an opening and shutting faucet that is set on the circulation line, starting the operation of the circulation pump and the combustion of the burner, the combustion corresponding to a quantity of heat for making the return water, which flows at the flow rate, a predetermined temperature, and stopping the operation of the circulation pump and the combustion of the burner when a predetermined time of the thermal process has passed.

9. The water heating control method of claim 8, further comprising:

detecting temperature of the tap water and/or the return water at an inlet part of the heat exchangers;

detecting flow rates of the tap water and/or the return water for the heat exchangers in the circulation line; and

calculating required quantity of heat based on an incoming flow rate for the heat exchangers and the detected temperature, stopping combustion of the heat exchangers based on the required quantity of heat, and stopping the circulation pump.

10. The water heating control method of claim 8, further comprising operating the circulation pump when the flow rate in the circulation line is a predetermined value or over or when the required quantity of heat of the tap water and/or the return water is a predetermined value or over, during the stop of the circulation pump.

11. The water heating control method of claim 8, further comprising moving the circulation pump to freezing prevention operation when hot water temperature in the circulation line is a predetermined value or below.