Heat pump water heater

Patent metadata

Field	Value
Publication number	US-9482446-B2
Application number	US-201314425652-A
Country	US
Kind code	B2
Filing date	Jul 23, 2013
Priority date	Sep 25, 2012
Publication date	Nov 1, 2016
Grant date	Nov 1, 2016

Abstract

A heat pump water heater includes: a compressor; a first water-refrigerant heat exchanger; a second water-refrigerant heat exchanger; refrigerant paths capable of forming a refrigerant circuit; and water channels including a flow channel, the flow channel leading hot water that has passed through the second water-refrigerant heat exchanger to the first water-refrigerant heat exchanger. The heat pump water heater is able to perform a heating operation. In the heating operation, the hot water heated in the second water-refrigerant heat exchanger is fed to the first water-refrigerant heat exchanger and the hot water further heated in the first water-refrigerant heat exchanger is supplied to a downstream side of the water channels. The first water-refrigerant heat exchanger is able to be replaced without replacing the second water-refrigerant heat exchanger.

First claim

The invention claimed is:

1. A heat pump water heater comprising:
a compressor configured to compress a refrigerant;
a first water-refrigerant heat exchanger configured to exchange heat between the refrigerant and water;
a second water-refrigerant heat exchanger configured to exchange heat between the refrigerant and water;
refrigerant paths capable of forming a refrigerant circuit, the refrigerant circuit supplying the refrigerant compressed by the compressor to the first water-refrigerant heat exchanger, the refrigerant circuit supplying the refrigerant that has passed through the first water-refrigerant heat exchanger to the second water-refrigerant heat exchanger; and
water channels including a flow channel, the flow channel leading hot water that has passed through the second water-refrigerant heat exchanger to the first water-refrigerant heat exchanger,
the heat pump water heater being able to perform a heating operation, the hot water heated in the second water-refrigerant heat exchanger being fed to the first water-refrigerant heat exchanger in the heating operation, the hot water further heated in the first water-refrigerant heat exchanger being supplied to a downstream side of the water channels in the heating operation,
the first water-refrigerant heat exchanger being able to be replaced without replacing the second water-refrigerant heat exchanger,
the compressor including a first inlet from which the refrigerant is drawn in, a first outlet from which the refrigerant drawn in from the first inlet is discharged, a second inlet from which the refrigerant is drawn in, and a second outlet from which the refrigerant drawn in from the second inlet is discharged,
the refrigerant paths including a path that leads the refrigerant discharged from the first outlet to the first water-refrigerant heat exchanger, a path that leads the refrigerant that has passed through the first water-refrigerant heat exchanger to the second inlet, and a path that leads the refrigerant discharged from the second outlet to the second water-refrigerant heat exchanger.

2. The heat pump water heater according to claim 1 , wherein the first water-refrigerant heat exchanger is small compared to the second water-refrigerant heat exchanger.

3. The heat pump water heater according to claim 1 , wherein an exit water temperature in the second water-refrigerant heat exchanger during the heating operation is 80° C. or less.

4. The heat pump water heater according to claim 1 , wherein an exit water temperature in the second water-refrigerant heat exchanger during the heating operation is 65° C. or more.

5. The heat pump water heater according to claim 1 , wherein, in the heating operation, a percentage of a heating power of the first water-refrigerant heat exchanger to a sum of the heating power of the first water-refrigerant heat exchanger and a heating power of the second water-refrigerant heat exchanger is 12% to 18%.

6. The heat pump water heater according to claim 1 , wherein the first water-refrigerant heat exchanger and the second water-refrigerant heat exchanger have the same design of a heat-transfer part and have different lengths of an interior flow path; and
wherein a ratio between a length of the flow path in the first water-refrigerant heat exchanger and a length of the flow path in the second water-refrigerant heat exchanger is 0.2:0.8 to 0.05:0.95.

7. The heat pump water heater according to claim 1 , wherein a ratio between an entire heat-transfer area in the first water-refrigerant heat exchanger and an entire heat-transfer area in the second water-refrigerant heat exchanger is 0.2:0.8 to 0.05:0.95.

8. The heat pump water heater according to claim 1 ,
wherein the compressor includes, in a sealed container, a compression element configured to compress the refrigerant, and a motor element configured to drive the compression element;
wherein the refrigerant drawn in from the first inlet is compressed by the compression element and then discharged from the first outlet; and
wherein the refrigerant drawn in from the second inlet cools the motor element and is then discharged from the second outlet.

9. The heat pump water heater according to any one of claim 1 , wherein the first water-refrigerant heat exchanger is disposed inside a chamber in which the compressor is disposed.

10. The heat pump water heater according to claim 1 , wherein the second water-refrigerant heat exchanger is disposed inside a chamber in which an evaporator configured to evaporate the refrigerant is disposed.

11. The heat pump water heater according to claim 1 , comprising:
a flow path narrowing detector to detect that flow path narrowing by a deposit precipitated from the hot water occurs in the first water-refrigerant heat exchanger; and
a user interface, if it is detected that the flow path narrowing occurs, to inform about an abnormality.

12. The heat pump water heater according to claim 1 , comprising:
a flow path narrowing detector to detect that flow path narrowing by a deposit precipitated from the hot water occurs in the first water-refrigerant heat exchanger; and
a controller, if it is detected that the flow path narrowing occurs, to decrease a temperature of the hot water supplied to the downstream side in the heating operation, compared to a case where the flow path narrowing is not detected.

13. The heat pump water heater according to claim 1 , comprising:
a flow path narrowing detector to detect that flow path narrowing by a deposit precipitated from the hot water occurs in the first water-refrigerant heat exchanger; and
a controller, if it is detected that the flow path narrowing occurs, to decrease a temperature of the refrigerant discharged from the compressor compared to a case where the flow path narrowing is not detected.

14. The heat pump water heater according to claim 1 , wherein a pressure on a high-pressure side of the refrigerant is a pressure exceeding a critical pressure.

15. A heat pump water heater comprising:
a compressor configured to compress a refrigerant;
a first water-refrigerant heat exchanger configured to exchange heat between the refrigerant and water;
a second water-refrigerant heat exchanger configured to exchange heat between the refrigerant and water;
refrigerant paths capable of forming a refrigerant circuit, the refrigerant circuit supplying the refrigerant compressed by the compressor to the first water-refrigerant heat exchanger, the refrigerant circuit supplying the refrigerant that has passed through the first water-refrigerant heat exchanger to the second water-refrigerant heat exchanger;
water channels including a flow channel, the flow channel leading hot water that has passed through the second water-refrigerant heat exchanger to the first water-refrigerant heat exchanger; and
a plurality of chambers,
the heat pump water heater being able to perform a heating operation, the hot water heated in the second water-refrigerant heat exchanger being fed to the first water-refrigerant heat exchanger in the heating operation, the hot water further heated in the first water-refrigerant heat exchanger being supplied to a downstream side of the water channels in the heating operation,
the first water-refrigerant heat exchanger being able to be replaced without replacing the second water-refrigerant heat exchanger,
the first water-refrigerant heat exchanger and the second water-refrigerant heat exchanger being disposed in different ones of the chambers.

16. The heat pump water heater according to claim 15 , wherein the first water-refrigerant heat exchanger is small comp

Assignees

• Mitsubishi Electric Corp

Inventors

• Nomoto So
• Hatanaka Kensaku
• Takayama Keisuke

Classifications

• F25B6/04

  arranged in series · CPC title

• F25B40/00

  Subcoolers, desuperheaters or superheaters · CPC title

• F25B2339/047

  Water-cooled condensers · CPC title

• F24D19/0092

  Devices for preventing or removing corrosion, slime or scale · CPC title

• F24H4/04 Primary

  Storage heaters · CPC title