Hot water supply apparatus and control method thereof

Patent metadata

Field	Value
Publication number	US-9507354-B2
Application number	US-201414149690-A
Country	US
Kind code	B2
Filing date	Jan 7, 2014
Priority date	Jan 18, 2013
Publication date	Nov 29, 2016
Grant date	Nov 29, 2016

Abstract

A conversion factor learning unit successively updates a temperature conversion factor by learning a performance ratio of an output heat quantity with respect to an input scale number corresponding to a requested heat quantity generation to a hot water supply apparatus. The temperature conversion factor learned by the conversion factor learning unit is reflected in arithmetic operation of an FF scale number by a feedforward control unit and arithmetic operation of the FB scale number by the feedback control unit. An integral control in the feedback control unit is preferably turned off.

First claim

What is claimed is:

1. A hot water supply apparatus comprising:
a heat exchanger configured to heat passing water by means of a heat quantity generated by a heat source mechanism;
a first temperature detector arranged on an upstream side of said heat exchanger;
a second temperature detector arranged on a downstream side of said heat exchanger;
a flow rate detector for detecting a passing flow rate through said heat exchanger; and
a control apparatus for setting a requested heat quantity generation to said heat source mechanism for each predetermined control cycle based on an inflow water temperature detected by said first temperature detector, a tapping temperature detected by said second temperature detector, a set temperature of said tapping temperature, and a flow rate detected by said flow rate detector,
said control apparatus including:
a learning unit for learning a conversion factor between a temperature and a heat quantity based on a performance ratio of an output heat quantity based on a temperature difference between said inflow water temperature and said tapping temperature and said flow rate with respect to said requested heat quantity generation to said heat source mechanism;
a feedforward control unit for calculating a first requested heat quantity generation based on a temperature difference between said set temperature and said inflow water temperature, said flow rate, and said conversion factor learned by said learning unit;
a feedback control unit for calculating a second requested heat quantity generation based on a temperature deviation of said tapping temperature with respect to said set temperature, said flow rate, a control gain, and said conversion factor learned by said learning unit; and
an addition unit for setting a requested heat quantity generation to said heat source mechanism by addition of said first requested heat quantity generation, and said second requested heat quantity generation.

2. The hot water supply apparatus according to claim 1 , wherein said learning unit is configured to raise a learning speed of reflecting said performance ratio to a learning value of said conversion factor when said flow rate is high, and to lower the learning speed when said flow rate is low.

3. The hot water supply apparatus according to claim 1 , wherein said control apparatus is configured to detect an abnormality of said hot water supply apparatus based on a value of said conversion factor learned by said learning unit.

4. The hot water supply apparatus according to claim 1 , wherein said control apparatus further includes an initial setting unit for setting said conversion factor at least as a function of said flow rate during an initial combustion period from starting of combustion by means of said heat source mechanism to a timing at which a shortage temperature of said tapping temperature with respect to said set temperature becomes smaller than a predetermined threshold value, and
said learning unit does not execute the learning of said conversion factor during said initial combustion period.

5. The hot water supply apparatus according to claim 4 , wherein said control apparatus is configured to set a learning initial value of said conversion factor by means of said learning unit in accordance with said conversion factor set by said initial setting unit at a time of termination of said initial combustion period.

6. The hot water supply apparatus according to claim 4 , wherein said control apparatus further includes a high temperature abnormality detecting unit for detecting occurrence of a high temperature abnormality when an excessive temperature of said tapping temperature with respect to said set temperature becomes higher than a predetermined threshold value, and
said initial setting unit is configured to set said conversion factor further based on occurrence times of said high temperature abnormality detected by said high temperature abnormality detecting unit so that said requested heat quantity generation is lowered as said occurrence times become greater with respect to the same said flow rate.

7. The hot water supply apparatus according to claim 6 , wherein said control apparatus is configured to reduce occurrence times of said high temperature abnormality based on a value of said conversion factor learned by said learning unit.

8. The hot water supply apparatus according to claim 1 , wherein said feedback control unit has a proportional feedback unit for calculating said second requested heat quantity generation by dividing a product of said temperature deviation, a proportional control gain, and said flow rate by said conversion factor.

9. The hot water supply apparatus according to claim 8 , wherein said learning unit is configured to raise a learning speed reflecting said performance ratio in a learning value of said conversion factor when said flow rate is high, and to lower the learning speed when said flow rate is low.

10. The hot water supply apparatus according to claim 8 , wherein said control apparatus is configured to detect an abnormality of said hot water supply apparatus based on a value of said conversion factor learned by said learning unit.

11. The hot water supply apparatus according to claim 8 , wherein said control apparatus further includes an initial setting unit for setting said conversion factor at least as a function of said flow rate during an initial combustion period from starting of combustion by means of said heat source mechanism to a timing at which a shortage temperature of said tapping temperature with respect to said set temperature becomes smaller than a predetermined threshold value, wherein
said learning unit does not execute the learning of said conversion factor during said initial combustion period.

12. The hot water supply apparatus according to claim 11 , wherein said control apparatus is configured to set a learning initial value of said conversion factor by said learning unit in accordance with said conversion factor set by said initial setting unit at a time of termination of said initial combustion period.

13. The hot water supply apparatus according to claim 11 , wherein said control apparatus further includes a high temperature abnormality detecting unit for detecting occurrence of a high temperature abnormality when an excessive temperature of said tapping temperature with respect to said set temperature becomes higher than a predetermined threshold value, and
said initial setting unit is configured to set said conversion factor further based on occurrence times of said high temperature abnormality detected by said high temperature abnormality detecting unit so that said requested heat quantity generation is lowered as said occurrence times become greater with respect to the same said flow rate.

14. The hot water supply apparatus according to claim 2 , wherein said feedback control unit does not execute an integration feedback based on an integration value of said temperature deviation and an integral control gain.

15. The hot water supply apparatus according to claim 14 , wherein said learning unit is configured to raise a learning speed of reflecting said performance ratio to a learning value of said conversion factor when said flow rate is high, and to lower the learning speed when said flow rate is low.

16. The hot water supply apparatus according to claim 14 , wherein said control apparatus is configured to detect an abnormality of said hot water apparatus based on a value of said conversion factor learned by said learning unit.

17. The hot water supply apparatus according to claim 1

Assignees

• Noritz Corp

Inventors

• Kusachi Rena
• Nakayama Kenichi
• Nabeshima Hiroki
• Maeshima Yuki

Classifications

• F23N2225/18

  feedwater temperature · CPC title

• F23N2225/19

  outlet temperature water heat-exchanger · CPC title

• G05D23/1917 Primary

  using digital means · CPC title

• F23N5/022

  using electronic means (F23N5/04 - F23N5/14 take precedence) · CPC title

• F23N1/082

  using electronic means · CPC title