JPH0227580B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is an engine-driven heat pump used as a heat source device for water heaters, air-conditioning equipment, etc. Regarding an engine-driven heat pump.

In such an engine-driven heat pump, by changing the number of operating compressors in accordance with changes in load, it is possible to always demonstrate sufficient heating capacity in response to the load. In a heat pump that is equipped with multiple compressors in parallel, the order of operation of the compressors is determined in advance, and if the number of compressors required to operate is one, the one compressor in the rank 1 is operated, and if the number of required operation is 2. The conventional system which adopted an operation order system in which the two compressors of rank 1 and rank 2 were operated in parallel in two cases had the following drawbacks.

In other words, when changing capacity, a compressor with an operating order of 1 is always operated, and compressors with a lower operating order are used more frequently, so there is a large variation in the lifespan (durability) of each compressor. Although it is equipped with multiple compressors in parallel, each compressor reaches its life limit at different times, making it necessary to replace each compressor, and the operating density of a particular compressor is high. Therefore, the compressor, which has a high operating density, has the disadvantage that it reaches its life limit faster than the original rate of life decline.

There are also systems in which the operating time of each compressor is accumulated and the compressor with the smallest accumulated value is operated preferentially based on the comparison result of the accumulated values. The compressor is driven by an engine, and the heating capacity for the load is adjusted by changing the compressor's rotation speed. The number of rotations during that time is different, so although it is possible to average out the life of each compressor somewhat compared to the conventional case described above, it is not enough and the compressor must be replaced frequently. There are drawbacks that require work.

The present invention has an object to overcome such conventional drawbacks.

Incidentally, although reference numerals are written in the claims section for convenient comparison with the drawings, the present invention is not limited to the structure shown in the accompanying drawings.

In order to achieve the above object, the present invention includes a device that individually integrates the rotation speed of each compressor, and a compressor that has the smallest integrated value based on a comparison result of the integrated values by this integrating device. It is equipped with an operation priority judgment mechanism that activates the system.

Therefore, according to the present invention, the following effects can be obtained.

B The priority of operation is determined based on the cumulative value of the compressor rotation speed, which is closely related to the life of the compressor, and the compressor with the lowest cumulative value is operated first, so control is based on the cumulative time. Compared to conventional technology, the lifespan of each compressor can be averaged with high precision, preventing undue stress from being applied to only a specific compressor, and enabling stable operation over a long period of time.

(b) According to the engine-driven heat pump of the present invention, all the compressors reach their life limits at the same time or almost simultaneously due to the highly accurate averaging of the lifespans, and the replacement timing of these compressors is concentrated. This has the effect of making maintenance work more efficient.

Embodiments of the present invention will be described below based on the drawings.

This is an engine-driven heat pump that is used as a heat source device for hot water supply equipment and air conditioning equipment A (hereinafter collectively referred to as load equipment).
The compressed refrigerant and the heated fluid of the heated fluid circulation circuit 4 of the load device A are heated to a refrigerant circuit 3 formed by two refrigerant compressors 2A, 2B connected in parallel, each driven by an engine 1A, 1B. A condenser 5 to be replaced, an expansion valve 6, and an air heat exchange type evaporator 7 are interposed, and the temperature of the fluid to be heated (that is,
A mechanism is provided to automatically control the number of operating compressors 2A, 2B and the rotational speed of the compressors 2A, 2B based on the load.

The automatic control mechanism includes a sensor 8 that detects the temperature (load) of the fluid to be heated, and based on the temperature detected by this sensor 8, controls the operating points of the compressors 2A and 2B and the A controller 9 that controls the rotation speed, that is, controls the speed governors 1a and 1b of each engine 1A and 1B, and a device 10A and 10B that integrates the rotation of each compressor 2A and 2B, that is, the engine 1A and 1B. and an operation priority determination mechanism 11 that preferentially operates the compressor (engine) with the smallest integrated value based on the integrated values of these integrating devices 10A and 10B.

As shown in Fig. 2, the heating capacity P of the heat pump varies between the first value P1 and the rotation speed of one compressor 2A or 2B in proportion to the change between the minimum value Na and the maximum value Nb _. The third value P3 and the _fourth value change in proportion to the change between the minimum value Na and the maximum value Nb of the rotation speed of the two compressors _2A and 2B. _P4
It changes between.

According to the configuration of the above embodiment, both compressors 2A and 2B operate at the beginning of operation when the temperature of the fluid to be heated is low, so that the load is small and only one compressor is required to operate. When it gets tired, the compressor 2A or 2 with the larger integrated rotational speed value
B stops operating, only the compressor 2B or 2A with the smaller cumulative rotational speed operates, and both compressors 2A, 2
The lifespan of engine B is averaged, and the lifespans of both engines 1A and 1B are averaged.

Note that the controller 9 includes one compressor 2A or 2B.
When the compressor 2A is in operation, during the operation, the compressor 2A
Alternatively, even if the integrated rotational speed value of compressor 2B becomes larger than the integrated rotational speed value of the other compressor 2B or 2A, the operation is stopped. Alternatively, one compressor 2A or 2B may be turned on until both compressors 2A, 2B are operated.
B or the cumulative rotation speed of one compressor 2A or 2B is
It is provided with a function of switching the compressor to be operated when one compressor 2A or 2B rotates at a set rotation speed after the rotation speed has become higher than the integrated value of rotation speed of B or 2A.

FIG. 3 shows another embodiment, in which two compressors 2A, 2B are connected to one engine 1A via clutches 12A, 12B, and the clutch 1
Compressor 2A, 2B by turning on/off 2A, 12B
It is configured to change the number of actuated units.
Since the other structures are the same as those in the embodiment, the same reference numerals are given and the explanation of the structures will be omitted.

In addition, in the embodiment, a heat pump equipped with two compressors 2A, 2B was shown, but it goes without saying that the present invention can be applied to a heat pump equipped with three or more compressors 2A, 2B, 2C, etc. .

[Brief explanation of drawings]

Figures 1 and 2 show examples, Figure 1 is a piping system diagram, Figure 2 is a graph showing the relationship between the rotation speed of the compressor and heating capacity, and Figure 3 is another example. It is a piping system diagram showing. 2A, 2B... Refrigerant compressor, 10A, 10B...
...integration device, 11...operation priority judgment mechanism.

Claims (1)

[Claims] 1 Multiple engine-driven refrigerant compressors 2A, 2B
In an engine-driven heat pump configured to be able to change the number of operating compressors according to fluctuations in heat load, the engine-driven heat pump includes devices 10A and 10B that individually integrate the rotational speed of each of the compressors 2A and 2B, and this integrating device 10.
An engine-driven heat pump characterized in that an operation priority determination mechanism 11 is provided that preferentially operates the compressor 2A or 2B with the smallest integrated value based on the comparison result of the integrated values by A and 10B.