JPH11193966A - Gas heat pump apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas heat pump apparatus for dealing with a low load operation of an indoor side without lowering an operating efficiency by regulating a capacity of an outdoor unit corresponding to a volume change of the indoor side. SOLUTION: The gas heat pump apparatus comprises a large volume compressor 1, a small volume compressor 11, a condenser 13, an expansion valve 15, an evaporator 17 and a piping for connecting them. A driving force of a gas engine 2 is transmitted to the compressors 1, 11 via an output shaft 2a, electromagnetic clutches 12, 19 and the like. The clutches 12, 19 decide whether a driving force from the engine 2 is transmitted to the compressors 1, 11 or not. Since the capacities of the two compressors 1, 11 are set to large and small capacities and the compressors 1, 11 can be selectively operated by the clutches 12, 19, it can deal with a low load operation of the indoor side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas heat pump (hereinafter, also referred to as GHP) having an engine using city gas or the like as fuel. In particular, the present invention relates to a gas heat pump device improved so as to be able to increase the efficiency at the time of low load operation.

[0002]

2. Description of the Related Art First, a basic configuration of a general GHP will be described. FIG. 3 is a system diagram showing a configuration of a GHP including a compressor driven by a gas engine. This GHP100
Comprises a compressor 101, a condenser 113, an expansion valve 115, an evaporator 117, and a pipe connecting them.

[0003] A compressor 101 is driven by a gas engine 102 (motor). The gas engine 102 is a reciprocating engine (or turbine) that receives supply of city gas from a gas supply pipe 103 and uses the gas as fuel.
The speed (output) of the gas engine 102 is controlled by a gas flow control valve 104 of a gas supply pipe 103. The compressor 101 sucks the refrigerant from the suction port 101a, compresses the refrigerant, and discharges the refrigerant from the discharge port 101b.

[0004] The compressed refrigerant is cooled and condensed in the condenser 113 by receiving external air from the fan 114. The condensed refrigerant is sent to an indoor air conditioner or the like, and is expanded by the expansion valve 115 and the evaporator 117.
A large amount of heat is taken from the air sucked in 18 to cool the room. The refrigerant returns from the evaporator 117 to the compressor 101 again, and thereafter circulates similarly.

[0005] Among them, the gas engine 102, the compressor 1
01, a condenser 113, a fan 114 and the like are unitized as an outdoor unit, and an expansion valve 115, an evaporator 11
7 and a fan 118 are unitized as an indoor unit. In the conventional GHP, the outdoor unit operates the engine at a high rotational speed when the load on the indoor unit is large, and operates the engine at a low rotational speed when the load on the indoor unit is small. In response to fluctuations.

[0006] The rotation speed range of a gas engine of an outdoor unit used for a general conventional GHP is such that the ratio of the maximum rotation speed to the minimum rotation speed (the maximum rotation speed: the minimum rotation speed) is about "3: 1". Has become. For example, the rated capacity of the outdoor unit is equivalent to 10 horsepower, and the rotation speed range of the gas engine is 1000 to 250.
Assuming 0 rpm, the rated capacity of the outdoor unit is usually
It is exhibited when the gas engine is driven at the maximum speed,
The capacity of the outdoor unit and the rotation speed of the gas engine are in a proportional relationship.

FIG. 4 is a graph showing the relationship between the capacity of the outdoor unit and the number of revolutions of the gas engine. As shown in FIG. 4, the minimum capacity of the outdoor unit is 100 rpm.
4 horsepower at 0 rpm (10/2500 × 1000)
It turns out that. For this reason, the minimum capacity (capacity) of the connected indoor unit is limited to 4 horsepower. In order to reduce the capacity of the indoor unit to 4 hp or less, some means have been conventionally taken.

FIG. 5 is a system diagram showing the configuration of a conventional GHP having a refrigerant bypass path. GH shown in FIG.
P120, in the configuration of the GHP 100 shown in FIG. 3, branches the refrigerant bypass path 121 from the middle of the refrigerant discharge pipe between the compressor 101 and the condenser 113, and connects the refrigerant bypass path 121 to the evaporator 117. Compressor 10
1 is connected in the middle of the refrigerant suction pipe. A refrigerant flow control valve 122 is provided in the refrigerant bypass passage 121 so that the flow rate of the refrigerant bypassed from the refrigerant discharge pipe to the refrigerant suction pipe can be adjusted.

In the configuration of the GHP 120, an arbitrary amount of refrigerant can be returned to the suction side of the compressor 101 through the bypass path 121 by adjusting the refrigerant flow control valve 122, and the refrigerant flowing into the indoor unit can be cooled. The amount can be adjusted. By such means, the capacity of the indoor unit can be limited to 4 horsepower or less.

Next, other conventional GHPs which can be used with the capacity of the indoor unit reduced to 4 horsepower or less will be described below.
FIG. 6 is a system diagram showing a configuration of a GHP having two compressors of the same capacity. The GHP 50 includes two compressors 51 of the same capacity, a condenser 43, an expansion valve 45, and an evaporator 4.
7 and a pipe connecting them.

Each compressor 51 has a gas engine 5
2 (motor), the driving force of the gas engine 52 is output by the output shaft 52a, the belt pulley 55, the belt 5
6, the belt pulley 58, and the electromagnetic clutch 42 in this order are transmitted to the respective compressors 51. Each compressor 51 sucks the refrigerant from each suction port 51a, compresses the refrigerant, and discharges the refrigerant from the discharge port 51b.

The refrigerant compressed by the two compressors 51 joins in the discharge-side refrigerant pipe, is sent to the condenser 43, is cooled by the outside air from the fan 44, and is condensed. The condensed refrigerant is sent to an indoor air conditioner or the like, and expanded by an expansion valve 45 and an evaporator 47. At this time, a large amount of heat is taken from air sucked by a fan 48 to cool the room. The refrigerant is
The evaporator 47 returns to the two compressors 51 again, and thereafter circulates similarly.

Here, the electromagnetic clutch 42 plays a role of a changeover switch for determining whether or not the driving force from the gas engine 52 is finally transmitted to the compressor 51.
Here, the gas engine 52 is a reciprocating engine (or turbine) that receives supply of city gas from the gas supply pipe 53 and uses the gas as fuel. The speed (output) of the gas engine 52 is controlled by the gas flow control valve 54 of the gas supply pipe 53.
Is controlled by Therefore, the capacity of the outdoor unit is determined by the driving force output from the gas engine 52 and the switching operation of the electromagnetic clutch 42.

The rotational speed range of the gas engine of the outdoor unit used in the above-mentioned conventional GHP 50 is such that the ratio of the maximum rotational speed to the minimum rotational speed (maximum rotational speed: minimum rotational speed) is about "3: 1". ing. For example, assuming that the rated capacity of the two compressors 51 of the outdoor unit is equivalent to 10 horsepower and the rotation speed range of the gas engine 52 is 1000 to 2500 rpm, the electromagnetic clutch 42 is switched within the rotation speed range. It is possible to obtain the capacity of the outdoor unit when only one compressor 51 is used and the capacity of the outdoor unit when two compressors 51 are used.

FIG. 7 is a graph showing the relationship between the capacity of the outdoor unit and the number of revolutions of the gas engine. From FIG. 7, the minimum capacity of this outdoor unit is 2 when the compressor 51 is used only and the rotation speed of the gas engine is 1000 rpm.
It is understood that the horsepower is (10/2500 × 1000/2). Therefore, according to this GHP, the minimum capacity (capacity) of the connected indoor unit can be reduced to 2 horsepower.

[0016]

However, according to the conventional refrigerant bypass type GHP as shown in FIG.
Since a part of the refrigerant compressed by the compressor is returned to the compressor as it is, there is a problem that the efficiency of the entire apparatus is reduced.

According to the conventional GHP using two compressors having the same capacity as shown in FIG. 6, the minimum capacity of the indoor unit that can be handled is, for example, 2 when the capacity of the outdoor unit is 10 horsepower. The horsepower was the limit, and it was not possible to perform low-load operation on the indoor side smaller than 2 horsepower.

The present invention has been made in view of such a problem, and an object of the present invention is to provide a gas heat pump device capable of coping with a low load operation on the indoor side without lowering the efficiency. .

[0019]

In order to solve the above-mentioned problems, a gas heat pump apparatus according to the present invention comprises: an engine using gas as fuel; two compressors driven by the engine; A gas heat pump apparatus including: a clutch for switching whether or not to transmit power between the compressors; wherein the capacity of the two compressors is made large and small. Since the capacity of the two compressors can be made large and small and only the small capacity compressor can be operated by the clutch, it is possible to solve the problem related to the low load operation on the indoor side.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a gas heat pump device according to the present invention will be described in detail with reference to the drawings. FIG.
Is a G of the present invention having two compressors with different capacities.
FIG. 2 is a system diagram illustrating a configuration example of an HP. The gas heat pump device 10 of the present invention includes a large-capacity compressor 1, a small-capacity compressor 11, a condenser 13, an expansion valve 15, an evaporator 17, and a pipe connecting them.

The large capacity compressor 1 is driven by a gas engine 2 (motor), and the driving force of the gas engine 2 is as follows.
The power is transmitted to the large-capacity compressor 1 via the output shaft 2a, the belt pulley 5, the belt 6, the belt pulley 8, and the electromagnetic clutch 12 in this order. Similarly, the small capacity compressor 11 is also driven by the gas engine 2 (motor), and the driving force of the gas engine 2 is the output shaft 2a, the belt pulley 5, the belt 7, the belt pulley 9, and the electromagnetic clutch. The information is sequentially transmitted to the small-capacity compressor 11 through 19. Each of the compressors 1 and 11 draws in refrigerant from the respective suction ports 1a and 11a, compresses the refrigerant, and discharges the refrigerant from the discharge ports 1b and 11b.

The refrigerant compressed by the two compressors 1 and 11 joins in the discharge side refrigerant pipe, is sent to the condenser 13, is cooled by the outside air from the fan 14, and is condensed. The condensed refrigerant is sent to an indoor air conditioner or the like, and expanded by the expansion valve 15 and the evaporator 17. At this time, a large amount of heat is taken from the air sucked by the fan 18 to cool the room.
The refrigerant returns from the evaporator 17 to the two compressors 1 and 11 again, and thereafter circulates similarly.

Here, the electromagnetic clutch 12 functions as a changeover switch for determining whether or not the driving force from the gas engine 2 is finally transmitted to the large capacity compressor 1. Similarly, the electromagnetic clutch 19 is used for the gas engine 2.
And serves as a changeover switch for deciding whether or not to transmit the final driving force to the small capacity compressor 11. Here, the gas engine 2 is a reciprocating engine (or turbine) that receives supply of city gas from the gas supply pipe 3 and uses the gas as fuel. The speed (output) of the gas engine 2 is controlled by a gas flow control valve 4 of a gas supply pipe 3. Therefore, the capacity of the outdoor unit of the GHP 10 of the present invention is determined by the driving force output from the gas engine 2, the switching operation of the electromagnetic clutches 12 and 19, and
Will be determined by the capacity of one compressor.

In the above-described GHP 10 of the present invention, the relationship between the large-capacity compressor 1 and the small-capacity compressor 11 is that the outdoor unit when the large-capacity compressor 1 is driven at the minimum rotation speed of the gas engine 2. (C1) is smaller than the capacity (C11) of the outdoor unit when the small capacity compressor 11 is driven at the maximum rotational speed of the gas engine 2 (C1 ≦ C11). desirable. For example, the range of the number of revolutions of the gas engine 2 is defined as the ratio of the maximum number of revolutions to the minimum number
1000 to 250 with a minimum rotation speed of “2.5: 1”
0 rpm, the rated capacity of the two outdoor compressors 1 and 11 is equivalent to 10 hp, the rated capacity of the large capacity compressor 1 is equivalent to 7 hp, and the rated capacity of the small capacity compressor 11 is equivalent to 3 hp. I do. At this time, by switching the electromagnetic clutches 12 and 19 within the range of the number of revolutions of the gas engine of 1000 to 2500 rpm, the capacity of the outdoor unit when only the small capacity compressor 11 is used, and the capacity of the large capacity compressor 1 The capacity of the outdoor unit when only the compressor is used and the capacity of the outdoor unit when the two compressors 1 and 11 are used can be obtained.

FIG. 2 is a graph showing the relationship between the capacity of the outdoor unit and the number of revolutions of the gas engine. From FIG. 2, the minimum capacity of this outdoor unit is 1.2 horsepower (10/2500 × 1000 × 3/10) when only the small capacity compressor 11 is used and the rotation speed of the gas engine is 1000 rpm. I understand. Therefore, according to the GHP 10 of the present invention, the minimum capacity (capacity) of the connected indoor unit can be reduced to 1.2 horsepower.

In FIG. 2, the capacity (C1) of the outdoor unit when the large capacity compressor 1 is driven at a minimum rotation speed of 1000 rpm of the gas engine 2 is 2.8 horsepower, and the small capacity compression Machine 11 has a maximum revolution of 250 of gas engine 2
The capacity (C11) of the outdoor unit when driven at 0 rpm is
Since it is 3 horsepower, the relationship of C1 ≦ C11 is satisfied. Further, the capacity (C1-11) of the outdoor unit when the two compressors 1 and 11 are driven at the minimum rotation speed of 1000 rpm of the gas engine 2 is 4 hp, and the large capacity compressor 1
Since the capacity (C1) of the outdoor unit when the gas engine 2 was driven at the maximum rotation speed of 2500 rpm is 7 horsepower,
The relationship of C1-11 ≦ C1 is satisfied. Therefore, by switching the electromagnetic clutches 12 and 19, 1.2 to 1
The capacity of the outdoor unit of 0 hp can be arbitrarily selected.
That is, the outdoor functional force can be adjusted within a range of 1.2 to 10 hp in response to the capacity fluctuation on the indoor unit side.

Although the embodiment of the gas heat pump apparatus of the present invention has been described above, it is sufficient that the capacity of each compressor is different, and optimally, the relationship of the above-mentioned condition C1 ≦ C11 is satisfied, and It is desirable that the rated capacity of the large capacity compressor is 40 to 60% of the rated capacity of the large capacity compressor.
The number of compressors used is not limited to two, and may be three or more. Further, the driving force from the gas engine may be varied by a clutch.

[0028]

As described above, according to the gas heat pump apparatus of the present invention, two compressors having different capacities are used, and the compressor used by the clutch can be selected. The capacity of the outdoor unit can be adjusted in response to fluctuations, and in particular, only a small-capacity compressor can be operated by means of a clutch, thus supporting low load operation on the indoor unit side without reducing efficiency. You can now.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an embodiment of a gas heat pump device according to the present invention.

FIG. 2 is a graph showing a relationship between an engine speed and an outdoor functional force by the gas heat pump device of the present invention.

FIG. 3 is a system diagram showing a configuration of a conventional general gas heat pump device.

FIG. 4 is a graph showing a relationship between an engine speed and an outdoor functional force by the gas heat pump device shown in FIG. 3;

FIG. 5 is a system diagram showing a configuration of a conventional gas heat pump device having a refrigerant bypass function.

FIG. 6 is a system diagram showing a configuration of a conventional gas heat pump device having two compressors of the same capacity.

FIG. 7 is a graph showing a relationship between an engine speed and an outdoor functional force by the gas heat pump device shown in FIG. 6;

[Explanation of symbols]

1, 11, 51, 101 Compressor 1a, 11a, 51a, 101a Suction port 1b, 11b, 51b, 101b Discharge port 2, 52, 102 Gas engine (motor) 2a, 52a Output shaft 3, 53, 1
03 Gas supply pipes 4, 54, 104 Gas flow control valves 5, 8, 9, 55, 58 Belt pulleys 6, 7, 56 Belts 12, 19, 4
2 Electromagnetic clutch 10, 50, 100, 120 Gas heat cycle 13, 43, 113 Condenser 14, 18, 44, 48, 114, 118 Fan 15, 45, 115 Expansion valve 17, 47,
117 Evaporator

Claims (3)

[Claims] 1. A gas including an engine using gas as a fuel, two compressors driven by the engine, and a clutch for switching whether or not to transmit power between the engine and each compressor. In the heat pump device;
A gas heat pump device, wherein the compressors have large and small capacities. 2. The capacity when the large capacity compressor is driven at the lowest speed of the engine is smaller than the capacity when the small capacity compressor is driven at the highest speed of the engine. The gas heat pump device according to claim 1, wherein: 3. The gas heat pump device according to claim 1, wherein the rated capacity of the small capacity compressor is 40 to 60% of the rated capacity of the large capacity compressor.