Heat source device

Patent metadata

Field	Value
Publication number	US-9605893-B2
Application number	US-201113881281-A
Country	US
Kind code	B2
Filing date	Oct 27, 2011
Priority date	Oct 29, 2010
Publication date	Mar 28, 2017
Grant date	Mar 28, 2017

Abstract

A heat source device is provided with a differential pressure sensor that measures the differential pressure between an inlet pressure and an outlet pressure for the chilled water in an evaporator and with a control device. The control device possesses the coefficient of loss for the evaporator and is provided with a chilled-water flow-rate computing portion that calculates a chilled-water flow rate at the evaporator on the basis of the coefficient of loss and the differential pressure output from the differential pressure sensor; a control-command computing portion that generates a control command by using a specification heating-medium flow rate that is set in advance; and a control-command correcting portion that corrects the control command generated by the control-command computing portion.

First claim

The invention claimed is:

1. A heat source device comprising:
a first heat exchanger that cools or heats a heating medium that flows in from an external load;
a second heat exchanger that performs heat exchange with external air or cooling water;
a refrigerant circulating channel that circulates refrigerant between the first heat exchanger and the second heat exchanger;
a centrifugal compressor provided in the refrigerant circulating channel;
a differential-pressure measuring unit that measures a differential pressure between an inlet pressure and an outlet pressure of the heating medium in the first heat exchanger; and
a controlling unit,
wherein the controlling unit comprises:
a flow-rate computing unit that calculates a flow rate of the heating medium in the first heat exchanger on the basis of the coefficient of loss for the first heat exchanger and the differential pressure output from the differential-pressure measuring unit;
a control-command computing unit that generates a control command by using a specification heating-medium flow rate that is set in advance; and
a control-command correcting unit that corrects the control command generated by the control-command computing unit on the basis of the difference between the heating-medium flow rate calculated by the flow-rate computing unit and the specification heating-medium flow rate;
wherein the controlling unit is configured to control at least the centrifugal compressor using the control command corrected by the control-command correcting unit.

2. The heat source device according to claim 1 , wherein the controlling unit further comprises:
a fault judging unit that judges whether or not the difference between the heating-medium flow rate calculated by the flow-rate computing unit and the specification heating-medium flow rate is equal to or greater than a predetermined threshold, which is set in advance, and for issuing an alarm, if the difference is equal to or greater than the threshold, to a monitoring device connected thereto via a communication line.

3. The heat source device according to claim 2 , wherein the flow-rate computing unit comprises:
a first computing unit that computes the heating-medium flow rate by using sampling data from the differential-pressure measuring unit; and
a second computing unit that applies smoothing processing on the sampling data from the differential-pressure measuring unit and for computing the heating-medium flow rate by using the smoothed sampling data,
wherein the fault judging unit performs fault judgment by using the heating-medium flow rate calculated by the first computing unit, and the control-command correcting unit corrects the control command by using the heating-medium flow rate calculated by the second computing unit.

4. The heat source device according to claim 1 , wherein, when the differential-pressure measuring unit has failed or a detection limit of the differential-pressure measuring unit has been exceeded, the controlling unit calculates an amount of heat exchanged at the first heat exchanger by substituting current power consumption at the centrifugal compressor and the amount of heat exchanged at the second heat exchanger into a relational expression that expresses the relationship between the power consumption at the centrifugal compressor, the amount of heat exchanged at the first heat exchanger, and the amount of heat exchanged at the second heat exchanger, and calculates the heating-medium flow rate on the basis of the calculated amount of heat exchanged at the first heat exchanger.

5. The heat source device according to claim 1 , wherein
the controlling unit includes a relational expression in which the relationship between the heating-medium flow rate and the performance of the heat exchanger is expressed and includes unit of determining the performance of the heat exchanger for the heating-medium flow rate calculated by the flow-rate computing unit on the basis of the relational expression and for detecting a performance deterioration of the heat exchanger.

6. The heat source device according to claim 2 , wherein, when the differential-pressure measuring unit has failed or a detection limit of the differential-pressure measuring unit has been exceeded, the controlling unit calculates an amount of heat exchanged at the first heat exchanger by substituting current power consumption at the centrifugal compressor and the amount of heat exchanged at the second heat exchanger into a relational expression that expresses the relationship between the power consumption at the centrifugal compressor, the amount of heat exchanged at the first heat exchanger, and the amount of heat exchanged at the second heat exchanger, and calculates the heating-medium flow rate on the basis of the calculated amount of heat exchanged at the first heat exchanger.

7. The heat source device according to claim 3 , wherein, when the differential-pressure measuring unit has failed or a detection limit of the differential-pressure measuring unit has been exceeded, the controlling unit calculates an amount of heat exchanged at the first heat exchanger by substituting current power consumption at the centrifugal compressor and the amount of heat exchanged at the second heat exchanger into a relational expression that expresses the relationship between the power consumption at the centrifugal compressor, the amount of heat exchanged at the first heat exchanger, and the amount of heat exchanged at the second heat exchanger, and calculates the heating-medium flow rate on the basis of the calculated amount of heat exchanged at the first heat exchanger.

8. The heat source device according to claim 2 , wherein
the controlling unit includes a relational expression in which the relationship between the heating-medium flow rate and the performance of the heat exchanger is expressed and includes unit of determining the performance of the heat exchanger for the heating-medium flow rate calculated by the flow-rate computing unit on the basis of the relational expression and for detecting a performance deterioration of the heat exchanger.

9. The heat source device according to claim 3 , wherein
the controlling unit includes a relational expression in which the relationship between the heating-medium flow rate and the performance of the heat exchanger is expressed and includes unit of determining the performance of the heat exchanger for the heating-medium flow rate calculated by the flow-rate computing unit on the basis of the relational expression and for detecting a performance deterioration of the heat exchanger.

10. The heat source device according to claim 4 , wherein
the controlling unit includes a relational expression in which the relationship between the heating-medium flow rate and the performance of the heat exchanger is expressed and includes unit of determining the performance of the heat exchanger for the heating-medium flow rate calculated by the flow-rate computing unit on the basis of the relational expression and for detecting a performance deterioration of the heat exchanger.

11. The heat source device according to claim 1 , wherein the flow-rate computing unit calculates the flow rate of the heating medium in the first exchanger on the basis of the coefficient of loss for the first heat exchanger, the differential pressure output from the differential-pressure measuring unit, and a correction term on the basis of the amount of liquid held in the first exchanger.

12. The heat source device according to claim 1 , wherein the controlling unit is configured to control the heat source device, and
wherein the control-command computing unit generates the control command fo

Assignees

• Wajima Kazuki
• Ueda Kenji
• Nitta Masaharu
• Mitsubishi Heavy Ind Ltd

Inventors

• Wajima Kazuki
• Ueda Kenji
• Nitta Masaharu

Classifications

• F25B2400/13

  Economisers · CPC title

• F25B2400/23

  Separators · CPC title

• F25B2700/21173

  at the outlet · CPC title

• F25B49/02

  for compression type machines, plants or systems · CPC title

• F25D17/02

  for circulating liquids, e.g. brine · CPC title