Hot-water supply system

• US 6,627,858 B2
• Filed: 11/28/2001
• Issued: 09/30/2003
• Est. Priority Date: 12/01/2000
• Status: Expired due to Term

• Current Assignee: Central Research Institute of Electric Power Industry, DENSO Corporation, Tokyo Electric Power Company Holdings, Incorporated (Nuclear Damage Compensation Decommissioning Facilitation Corp.)
• Original Assignee: Central Research Institute of Electric Power Industry, DENSO Corporation, Tokyo Electric Power Company
• Inventors: Takahashi, Eiji, Yoshimi, Tomohisa, Nomura, Satoshi, Sakakibara, Hisayoshi, Kusakari, Kazutoshi, Saikawa, Michiyuki, Kobayakawa, Tomoaki
• Primary Examiner(s): Hoang, Tu Ba
• Application Number:
  US09/996,447
• Publication Number:
  US 20020125242A1
• Time in Patent Office: 671 Days
• Field of Search: 219/482, 219/483, 219/485, 219/486, 219/492, 219/487, 219/490, 219/497, 219/494, 219/501, 219/506, 219/508, 392/454, 392/463, 392/498, 392/449, 236/12.12, 236/20.R, 236/46.R, 236/78.D, 236/25.R, 122/14.22, 122/13.3, 237/8.R, 237/8.C, 237/12.3 B, 621/85, 624/34
• US Class Current: 219/492
• CPC Class Codes: F24D 19/1054 the system uses a heat pump

Abstract

In a control unit of a hot-water supply system, a boiling time period is estimated based on a hot-water amount stored in a tank at a time of 23:00, a boiling start time is adjusted so that boiling operation is finished at a time immediately before 7:00. For example, when the hot water amount stored in the tank is smaller at the time of 23:00, the boiling time period is made longer and the boiling start time is made earlier. On the other hand, when the hot water amount stored in the tank is larger at the time of 23:00, the boiling time period is made shorter and the boiling start time is made later.

Claims

1. A hot-water supply system comprising:

a tank having a water inlet side to which water from a water supply source is supplied, and a hot-water storing side for storing heated hot water for a supply;

a water-heating unit for heating water introduced from the water inlet side of the tank, and for sending heated hot water to the hot-water storing side of the tank, the water-heating unit being disposed to be electrically operated; and

a control unit for controlling operation of the water-heating unit, wherein,

the control unit includes

use heat-quantity calculating means for calculating a heat quantity used in a predetermined time period based on a hot-water supply amount from the tank in the predetermined time period, and for learning the heat quantity used in the predetermined time period,

target heat-quantity calculating means for calculating a target heat quantity for boiling, based on the learned heat quantity in the use heat-quantity calculating means,

target temperature calculating means for calculating a target boiling temperature of water, based on the target heat quantity calculated by the target heat-quantity calculating means, and

boiling means for performing boiling operation of the water-heating unit by a necessary boiling amount, based on the target boiling temperature calculated from the target temperature calculating means.

2. The hot-water supply system according to claim 1, wherein the control unit further includes

time-zone heat-quantity calculating means for calculating and learning a heat quantity used in each time zone, based on each hot-water supply amount during a plurality of time zones in which power rate are different from each other,

present heat-quantity calculating means for calculating a heat quantity stored in hot water within the tank at the present time,

shortage estimating means for estimating a shortage of the heat quantity stored in hot water within the tank, based on the heat quantity from the time-zone heat quantity calculating means and the heat quantity from the present heat quantity calculating means, and

compulsory-boiling means for additionaly performing the boiling operation in accordance with a shortage amount of the heat quantity when the shortage is estimated by the shortage estimating means.

3. The hot-water supply system according to claim 2, wherein:

the time zones includes an evening time zone in which a using amount of hot water is greatly increased than the other time zones;

the control unit performs operations of the time-zone heat-quantity calculating means, the present heat-quantity calculating means, the shortage estimating means and the compulsory-boiling means, at least before the evening time zone.

4. The hot-water supply system according to claim 1, wherein:

the predetermined time period is the last seven days; and

the target heat quantity for boiling is a maximum using heat quantity for the last seven days.

5. The hot-water supply system according to claim 1, wherein,

when the target boiling temperature calculated by the target temperature calculating means is higher than a predetermined temperature, the boiling means performs the boiling operation even in a time zone except for a midnight time zone which is cheapest in power rate.

6. The hot-water supply system according to claim 5, wherein the control unit includes compulsory-boiling time calculating means for calculating a compulsory-boiling time based on the target boiling temperature and a heat quantity of hot water stored in the tank, when the boiling means performs the boiling operation in the time zone except for the midnight time zone.

7. The hot-water supply system according to claim 1, wherein the boiling means includes

boiling time calculating means for calculating a necessary boiling time period for which the boiling operation is performed and the tank is filled with hot water, and

boiling-start time calculating means for calculating a boiling-start time based on the necessary boiling time period in such a manner that the boiling operation is finished at a time immediately before a finish time of a midnight time zone which is cheapest in power rate.

8. The hot-water supply system according to claim 7, wherein the boiling time calculating means calculates a water flow amount by using at least one of a standard boiling capacity, the target boiling temperature and a standard water temperature, to calculate the necessary boiling time period.

9. The hot-water supply system according to claim 7, wherein the boiling time calculating means calculates a water flow amount by using at least one of a standard boiling capacity, the target boiling temperature, a standard water temperature and an estimate heat quantity used for hot water supplied during the boiling operation, to calculate the necessary boiling time period.

10. The hot-water supply system according to claim 9, wherein the estimate heat quantity is a maximum heat quantity used for hot water supplied in the boiling operation during the last seven days.

11. The hot-water supply system according to claim 10, wherein the boiling means performs the boiling operation when a heat quantity stored in hot water within the tank at the present time is lower than the target heat quantity for boiling.

12. A hot-water supply system comprising:

a tank having a water inlet side to which water from a water supply source is supplied, and a hot-water storing side for storing heated hot water for a supply;

a water-heating unit for heating water introduced from the water inlet side of the tank, and for sending heated hot water to the hot-water storing side of the tank, the water-heating unit being disposed to be electrically operated; and

a control unit for controlling operation of the water-heating unit, wherein,

the control unit includes

use heat-quantity calculating means for calculating a heat quantity used in a predetermined time period based on a hot-water supply amount from the tank in the predetermined time period, and for learning the heat quantity used in the predetermined time period,

target heat-quantity calculating means for calculating a target heat quantity for boiling, based on the learned heat quantity in the use heat-quantity calculating means,

first boiling means for performing boiling operation of the water-heating unit based on the target heat quality for boiling, in a midnight time zone which is cheapest in power rate,

first boiling time calculating means for calculating a first boiling time period for which the boiling operation is performed and the tank is filled with hot water in the midnight time zone, and

boiling-start time calculating means for calculating a boiling-start time in the midnight time zone based on the first boiling time period in such a manner that the boiling operation is finished at a time immediately before a finish time of the midnight time zone.

13. The hot-water supply system according to claim 12, wherein the control unit further includes

time-zone heat-quantity calculating means for calculating and learning a heat quantity used in each time zone, based on each hot-water supply amount during a plurality of time zones in which power rate are different from each other,

present heat quantity calculating means for calculating a heat quantity stored in hot water within the tank at the present time,

shortage estimating means for estimating a shortage of the heat quantity stored in hot water within the tank, based on the heat quantity from the time-zone heat quantity calculating means and the heat quantity from the present heat quantity calculating means, and

second boiling means for additionally performing the boiling operation in accordance with a shortage amount of the heat quantity when the shortage is estimated by the shortage estimating means.

14. The hot-water supply system according to claim 13, wherein:

the time zones includes an evening time zone in which a using amount of hot water is greatly increased than the other time zones; and

second boiling means performs the boiling operation at least before the evening time zone.

15. The hot-water supply system according to claim 13, wherein the control unit includes a second boiling time calculating means for calculating a second boiling time period for which the boiling operation is performed in a time zone except for the midnight time zone, when the heat quantity of hot water stored in the tank is smaller than a first predetermined value.

16. The hot-water supply system according to claim 15, wherein the second boiling means performs the boiling operation for the second boiling time period until the heat quantity of hot water stored in the tank is increased to a second predetermined value that is smaller than a filled value where the tank is filled with hot water.

17. The hot-water supply system according to claim 12, wherein:

the control unit includes hot-water amount detecting means for detecting a hot-water amount stored in the tank;

as the hot-water amount stored in the tank at a start time of the midnight time zone is smaller, the first boiling time period is set longer and the first boiling start time is set earlier.

18. The hot-water supply system according to claim 12, wherein:

the control unit includes hot-water amount detecting means for detecting a hot-water amount stored in the tank;

as the hot-water amount stored in the tank at a start time of the midnight time zone is larger, the first boiling time period is set shorter and the first boiling start time is set later.