JP5201183B2 - Air conditioner and method of operating refrigerator - Google Patents

Description

  The present invention relates to an air conditioner and a method for operating a refrigerator, and more specifically, to an operation method for a refrigerator that can be operated at a maximum efficiency point that matches the characteristics of a heat source device, and an air conditioner.

  The coefficient of performance (hereinafter abbreviated as “COP”), which is a measure of the performance of a refrigerator, is the ratio between the amount of heat drawn from the low temperature side and the work done from the outside to carry the heat, and per 1 kW of power consumption It is the value showing the cooling and heating ability of COP is widely used as an index indicating the performance of the rated condition of the cooling device.

  The maximum efficiency point of the refrigerator is not necessarily the same as the rated design point, but varies depending on the cooling water temperature, the outside air temperature, the heat medium (cold water, brine, etc.) temperature, and the load factor. In refrigerators capable of variable flow operation, the heat transfer rate of the heat medium pump is reduced by changing the heat medium flow rate according to the partial load. It is greatly influenced by.

Various operating methods of the refrigerator are disclosed in Patent Documents 1-6.
Ordinary refrigerators employ a constant flow rate method, and operate in accordance with load fluctuations. For this reason, the COP of the refrigerator varies depending on the load according to the load. Moreover, in the case of the heat storage tank system which connects and operates a refrigerator with a heat storage tank, generally inlet temperature or compressor output (input current) was controlled so that it might become 100% load. For this reason, if the load factor is reduced focusing only on the COP, the conveyance power is wasted.

  In general, the refrigerator is often operated in a closed circuit. For this reason, if the bleed-in and variable flow rate control is controlled not for the secondary water amount request but for the refrigerator efficiency, the required water amount and the differential pressure cannot be ensured.

  For the above reasons, it has not been done so far to reduce the load factor by focusing only on the COP of the refrigerator.

JP 2002-22245 A JP-A-2005-114205 JP 2005-214608 A JP-A-2005-257116 JP 2006-242480 A JP 2008-70004 A

  An object of the present invention is to provide a refrigerator operating method and an air conditioner that can be operated with a desired coefficient of performance that matches the characteristics of the heat source machine, for example, with the highest coefficient of performance.

The present invention is based on the following findings (1) to (4).
(1) By installing a heat medium storage tank in the refrigerator and realizing a constant load operation based on the temperature of the heat medium storage tank, the heat source characteristics of the refrigerator under these operating conditions are not affected by the characteristics of the refrigerator. It is possible to operate with the desired coefficient of performance, for example, with the highest coefficient of performance, enabling energy-saving operation.

(2) By using a variable flow rate (with an inverter) for the cold water (hot water) pump, the conveyance power can be reduced according to the load.
(3) Even when there is cooling water such as a normal water cooler, it is possible to cope with variable flow rate in recent years, so that the power of the cooling water pump can be reduced according to the load.

  (4) In the heat storage tank method (cold water / hot water storage tank), there is a buffer called a storage tank, and the inlet temperature of the refrigerator can be controlled at all times, and since the transfer power is used effectively (generally at a constant speed), In order to ensure the amount of heat storage, it is common to perform refrigerator rated operation.

The present invention includes a heat source facility and a secondary side facility that is air-conditioned by the heat source facility, and the heat source facility stores a refrigerator and a heat medium that circulates through the refrigerator and the secondary side facility. Having a tank, the refrigerator inlet temperature of the heating medium supplied to the refrigerator from the heating medium storage tank, and the flow rate of the heating medium are respectively controlled to predetermined values ,
The refrigerator has the following characteristics between the load factor and the coefficient of performance:
[Characteristic]
A low load factor region that gives a coefficient of performance distribution less than a predetermined critical value, and a high load factor region that is continuous to the low load region factor and gives a coefficient of performance distribution that is greater than or equal to the predetermined critical value and has the highest value And depending on the outside air conditions of the secondary equipment, and
The air conditioner is characterized in that the flow rate of the heat medium is a flow rate corresponding to a load factor with the coefficient of performance of the refrigerator as the maximum value according to the outside air condition .

From another point of view, the present invention relates to a refrigerator that circulates a heat medium between a heat source facility including a refrigerator, a secondary-side facility that is air-conditioned by the heat source facility, and a heat medium storage tank that constitutes the heat source facility. When operating the refrigerator, the refrigerator inlet temperature of the heating medium supplied from the heating medium storage tank to the refrigerator and the flow rate of the heating medium are controlled to predetermined values, respectively, to operate the refrigerator with a desired coefficient of performance. The refrigerator has the following characteristics between the load factor and the coefficient of performance:
[Characteristic]
A low load factor region that gives a coefficient of performance distribution less than a predetermined critical value, and a high load factor region that is continuous to the low load region factor and gives a coefficient of performance distribution that is greater than or equal to the predetermined critical value and has the highest value And the flow rate of the heating medium commensurate with the load factor corresponding to the outside air condition and having the coefficient of performance of the refrigerator as the maximum value. It is the operating method of the refrigerator characterized by the flow rate .

In these invention, start-stop of the refrigerator is carried out by the temperature condition of the heat medium storage tank, the operating point of the refrigerator is controlled by the refrigerant pump flow rate, and by the refrigerator inlet temperature of the heating medium.

  According to the present invention, since the heat medium storage tank is installed in the heat source device, the refrigerator with a desired coefficient of performance, for example, the highest coefficient of performance, without depending on the characteristics of the refrigerator, for example, Can be operated.

FIG. 1 is an explanatory diagram schematically showing a cold water piping system of the air conditioner according to the first embodiment. FIG. 2 is a graph showing the relationship between the load factor of the refrigerator 4 and the coefficient of performance. FIG. 3 is an explanatory diagram schematically showing a cold water piping system of the air conditioner according to the second embodiment. Drawing 4 is an explanatory view showing typically the cold water piping system of air-conditioner 1 of an example.

[Embodiment 1]
DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described with reference to the accompanying drawings.
FIG. 1 is an explanatory view schematically showing a cold water piping system of an air conditioner 1 of the present invention.

  As shown in the figure, the air conditioner 1 includes a heat source facility (load) 2 and a secondary side facility (load) 3. In addition, the code | symbol 10 in FIG. 1 shows an air conditioner.

[Heat source equipment 2]
The heat source facility 2 includes a refrigerator 4, a heat medium storage tank 5, and a heat exchanger 6.

FIG. 2 is a graph showing the relationship between the load factor of the refrigerator 4 and the coefficient of performance.
As shown in FIG. 2, this characteristic is a low load factor region that gives a coefficient of performance distribution less than a predetermined critical value according to the outside air condition of the secondary side equipment 3 (load factor of less than 40% in the graph shown in FIG. 2). And a high load factor region (shown in FIG. 2) that is continuous with this low load factor and gives a coefficient of performance distribution that is equal to or higher than a predetermined critical value according to the outside air condition of the secondary equipment 3 and has the highest value. In the graph, it is desirable that the load factor is 40% or more. The reason for this will be explained.

  In the case of a refrigerator having a characteristic that the coefficient of performance deteriorates when it falls to the right from the rating, there is no merit of performing the control of the present invention, but in recent years the COP characteristic tends to be flat as shown in FIG. In addition, many refrigerators have a characteristic curve in which the coefficient of performance rapidly decreases when the load factor is less than 50%. In such a case as well, depending on the setting of the capacity of the heat medium storage tank 5, the actual load is 20%, but it can be used as a buffer, such as operating at about 50%, and efficient operation can be achieved. This is because the operation with a desired coefficient of performance matched to the characteristics of the heat source machine is possible, and the effect of the present invention becomes clear.

The heat medium storage tank 5 stores a heat medium that circulates through the refrigerator 4 and the secondary side equipment 3 described later.
In the present invention, the refrigerator inlet temperature of the heating medium supplied from the heating medium storage tank 5 to the refrigerator 4 and the flow rate of the heating medium are controlled to predetermined values, respectively. Thus, the refrigerator 4 is operated with a desired coefficient of performance.

In particular, when the flow rate of the heat medium is a flow rate corresponding to the load factor with the highest coefficient of performance of the refrigerator 4 according to the outside air conditions, the refrigerator 4 is operated with the highest coefficient of performance.
The start and stop of the refrigerator 4 is performed according to the temperature condition of the heat medium storage tank 5, and the operating point of the refrigerator 4 is controlled by the flow rate of the heat medium pump and the temperature of the heat medium refrigerator.

In the heat source facility 2, the refrigerator 4 is normally operated with the outlet temperature t 0 constant control (Δt = constant) by detecting the inlet temperature te, regardless of the type, for producing air-conditioning cold water.
In the present invention, the heat medium storage tank 5 is installed to make up for the difference between the secondary load 3 and the heat source load 2, but the heat exchanger 6 may not be installed.

[Secondary equipment 3]
The secondary side equipment 3 is air-conditioned by the heat source equipment. The secondary side (demand side) facility 3 normally blows air with variable flow rate control with a constant air temperature of the air conditioner in accordance with the total load demand in each room (= secondary side load).

  In general, in the heat storage system, heat is stored at full load (100% load) with inexpensive late-night power at night, and necessary water is sent to the secondary side during the day. On the other hand, in the present invention, the refrigerator 4 is basically operated with the heat source load that provides the highest efficiency under the outside air temperature condition regardless of the secondary side load.

On the other hand, in this invention, the effect listed below can be acquired compared with the conventional driving | running method.
(A) The refrigerator 4 is operated at the highest efficiency point not depending on the secondary load by arranging the heat medium storage tank 5. In the present invention, it is possible to construct a system in which the heat medium storage tank 5 is a heat storage tank. In general, in a system in which the heat medium storage tank 5 is considered as a cushion tank, the storage tank has a water amount of about 0.5 to 2 hours of operation of the refrigerator. It will be a storage tank with a volume of water that can be operated.

(B) By setting the heat medium pump to a variable flow rate (inverter), the conveyance power can be reduced according to the load.
(C) The most recent specific example is an air-cooled HP, so there is no cooling water pump, but even a normal water-cooling machine can cope with a variable cooling water flow rate in recent years. Or it can be operated according to the load.

[Embodiment 2]
Embodiment 2 will be described.
FIG. 3 is an explanatory view schematically showing a cold water piping system of the air conditioner 1-1 of the second embodiment.

The first embodiment is a case where the heat medium storage tank 5 is installed in the underground or the like, whereas the present embodiment is a case where the heat medium storage tank 5 is installed on the roof or the like.
In the present embodiment, headers 7 and 8 are arranged in place of the heat exchanger 6 in the first embodiment. By installing the headers 7 and 8, when the heat medium storage tank 5 is installed on the rooftop, etc., the air-conditioning piping system that directly connects the heat source equipment side 1 and the secondary equipment (load side) with piping Can do.

  According to the present embodiment, even when the heat medium storage tank 5 is installed on the rooftop or the like, the same effect as in the first embodiment can be obtained.

Drawing 4 is an explanatory view showing typically the cold water piping system of air-conditioner 1 of an example.
In the figure, reference numeral 1 is an air conditioner 1, reference numeral 2 is a heat source facility (load), reference numeral 3 is a secondary equipment (load), reference numeral 4 is a refrigerator, and reference numeral 5 is a heat medium storage. It is a tank.

  Reference sign INV is an inverter, reference sign SCP is a heat source pump, reference sign FC is a flow rate adjusting valve, and reference sign CP1 is a transport pump to the secondary side. Furthermore, the arrows in the figure indicate the flow of cold water.

The refrigerator 4 has a relationship as shown in FIG. 2 with the outside air temperature as a variable between the COP and the load factor.
In FIG. 4, the flow rate of the refrigerator 4 is controlled by the inverter and the FCV so that the load factor of the refrigerator 4 becomes the highest efficiency point. If the flow rate of CP1 (secondary-side required flow rate) <the flow rate of SCP, the heat medium water is stored in the heat medium storage tank 5. If the flow rate of CP1 (secondary side required flow rate) <the flow rate of SCP, the heat transfer water stored in the heat transfer medium storage tank 5 is released.

  In this way, according to the present invention, the refrigerator can be operated with a desired coefficient of performance, for example, the highest coefficient of performance, without depending on the characteristics of the refrigerator. .

1, 1-1 Air conditioner 2 Heat source equipment (load)
3 Secondary equipment (load)
4 Refrigerator 5 Heat storage tank 6 Heat exchanger 7, 8 Header

Claims (2)

A heat source facility and a secondary side air-conditioned by the heat source facility,
The heat source facility includes a refrigerator, and a heat medium storage tank that stores a heat medium circulating through the refrigerator and the secondary facility,
The refrigerator inlet temperature of the heating medium supplied from the heating medium storage tank to the refrigerator, and the flow rate of the heating medium are respectively controlled to predetermined values ;
The refrigerator has the following characteristics between the load factor and the coefficient of performance:
[Characteristic]
A low load factor region that gives a coefficient of performance distribution less than a predetermined critical value, and a high load factor region that is continuous to the low load region factor and gives a coefficient of performance distribution that is greater than or equal to the predetermined critical value and has the highest value And depending on the outside air conditions of the secondary equipment, and
The air conditioner according to claim 1, wherein the flow rate of the heat medium is a flow rate corresponding to a load factor with the coefficient of performance of the refrigerator as the maximum value according to the outside air condition . When operating the refrigerator while circulating a heat medium between a heat source facility provided with a refrigerator, a secondary-side facility air-conditioned by the heat source facility, and a heat medium storage tank constituting the heat source facility, Operating the refrigerator with a desired coefficient of performance by controlling the refrigerator inlet temperature of the heating medium supplied from the medium storage tank to the refrigerator and the flow rate of the heating medium to predetermined values, respectively , The machine shall have the following characteristics between the load factor and the coefficient of performance:
[Characteristic]
A low load factor region that gives a coefficient of performance distribution less than a predetermined critical value, and a high load factor region that is continuous to the low load region factor and gives a coefficient of performance distribution that is greater than or equal to the predetermined critical value and has the highest value And the flow rate of the heating medium commensurate with the load factor corresponding to the outside air condition and having the coefficient of performance of the refrigerator as the maximum value. A method of operating a refrigerator characterized by a flow rate .