JPH0228068B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a heat pump type air conditioner having both an air conditioning function and a hot water supply function, and particularly relates to an improvement in a method for controlling the rotation speed of a compressor thereof.

[Technical background of the invention and its problems]

Air conditioners with heating and cooling functions are often used in living rooms and dining rooms, and heat pump heating with an automatic timer is particularly comfortable for heating during breakfast during the coldest months.

On the other hand, many households in Japan have gas instantaneous water heaters installed, but it is necessary to change the system so that the hot water supplied by the gas instantaneous water heaters can be supplied from an air conditioner installed in the living room. For example, it leads to energy savings, which has great benefits for users.

Figures 1 to 3 show a conventional air conditioner equipped with a hot water storage tank in place of a gas instantaneous water heater. Figure 1 is for cooling, Figure 2 is for heating, and Figure 3 is for heating. Each indicates the time of hot water storage.

1 to 3, a pipe line 2 equipped with a compressor 1, a pipe line 6 equipped with an outdoor heat exchanger 3, a capillary tube 4, and an indoor heat exchanger 5 connect a four-way valve 7. connected via. A check valve 8 and a liquid tank 9 are interposed in the pipe line 6a between the outdoor heat exchanger 3 and the capillary tube 4, and the liquid tank 9 includes the outdoor heat exchanger 3 and the check valve 8. A bypass pipe 11 equipped with an expansion valve 10 and communicating with the pipe 6a between them is connected.

This air conditioner also includes a hot water storage tank 12 that stores hot water to be supplied to the kitchen, etc. Inside the hot water storage tank 12, there are a pair of hot water storage heat exchangers 13 and 14.
is provided. One of the hot water storage heat exchangers 13 is connected to a bypass pipe 15 whose both ends communicate with the four-way valve 7 and the pipe 6b of the outdoor heat exchanger 3, and is connected to the pipe 6b. A three-way valve 1 is provided at one end of the bypass pipe 15 communicating with the
6 is interposed. In addition, the other hot water storage heat exchanger 14 includes pipe lines 6c before and after the indoor heat exchanger 5,
6b and other bypass pipes 19 communicating with each other via three-way valves 17 and 18, respectively.

Next, the operation of the conventional device described above will be explained.

Figure 1 shows the state during cooling, where the four-way valve 7 and the three-way valves 16, 17, and 18 are regulated to the positions shown, so that the refrigerant flows through the pipes shown in bold lines as shown by the arrows. . Then, hot water tank 12
Since the high temperature and high pressure gas refrigerant discharged from the compressor 1 flows through the hot water storage heat exchanger 13 in the hot water storage tank 12, the water stored in the hot water storage tank 12 is heated by exchanging heat with the refrigerant. .

Figure 2 shows the state during heating, where the refrigerant flows through the pipes shown in thick lines as shown by the arrows.
Refrigerant does not flow into the hot water storage tank 12. Therefore, during this heating, the water stored in the hot water storage tank 12 is not heated, so if you want to warm the water in the hot water storage tank 12, it is necessary to switch to the hot water storage mode shown in FIG. 3.

Figure 3 shows this state during hot water storage.
The refrigerant flows through the pipe line shown by the thick line as shown by the arrow.
The high temperature and high pressure gas refrigerant discharged from the compressor 1 is
The bypass pipe 1 does not flow to the indoor heat exchanger 5.
9 and flows through the hot water storage heat exchanger 14 in the hot water storage tank 12. Therefore, the water stored in the hot water storage tank 12 is heated by exchanging heat with the refrigerant.

However, the conventional system described above has two bypass pipes 15, 19 to the hot water storage tank 12 and three three-way valves 16, 17, 18 provided in both bypass pipes 15, 19. This makes the circuit complicated, making it unsuitable for household use in terms of cost and reliability.
Since the refrigerant remains in the refrigerant 9, a stable refrigeration cycle cannot be maintained, and furthermore, as mentioned above, water cannot be heated during heating, which has various drawbacks.

An air conditioner shown in FIGS. 4 and 5 which eliminates the drawbacks of the conventional air conditioner has already been proposed by the applicant of the present invention in U.S. Pat.

This air conditioner will be explained below with reference to FIGS. 4 and 5. In addition, the same reference numerals are used in the drawings to refer to the same configuration as the conventional one described above.
The explanation will be omitted.

FIG. 4 shows the cooling mode, and FIG. 5 shows the heating mode. A hot water supply heat exchanger 20 is installed in the discharge side pipe 6e of the compressor 1 between the compressor 1 and the four-way valve 7. A water pipe 21 is inserted through this heat exchanger 20 for hot water supply. Also, this water pipe 2
1 is equipped with an on-off valve 22 to prevent cold water from flowing out even if a hot water faucet (not shown) is opened when the hot water heat exchanger 20 is not sufficiently warmed up.

According to such a configuration, the high temperature gas refrigerant discharged from the compressor 1 is supplied into the hot water heat exchanger 20 during the cooling operation shown in FIG. 4 and during the heating operation shown in FIG. The water in the pipe 21 is rapidly heated, and hot water is supplied when a faucet (not shown) is opened. By the way, since the on-off valve 22 is closed when the temperature of the hot water is low, a situation in which cold water is supplied when the faucet is opened does not occur.

However, when performing hot water supply operation in the above-described systems shown in FIGS. 4 and 5, if the compressor 1 is operated at a constant speed, as shown in FIG.
The lower the outdoor temperature is, and the lower the water temperature (inlet water temperature) in the water pipe 21 at the inlet of the hot water heat exchanger 20, the lower the hot water temperature. Therefore, sufficient hot water cannot be obtained in cold regions.
Also, when performing heating operation and hot water supply operation at the same time,
Furthermore, the capacity will be insufficient and the hot water temperature will drop.

For this reason, in the case of FIGS. 4 and 5, the capacity variable type compressor 1
The rotation speed of the compressor 1 is controlled according to the difference between the water temperature in the water pipe 21 at the outlet of the hot water supply heat exchanger 20 (hot water supply water temperature) and the set water temperature.

However, even with this arrangement, stable control cannot be achieved because it takes time for the outlet water temperature to change after the rotation speed of the compressor 1 changes.

[Purpose of the invention]

In view of the above-mentioned points, an object of the present invention is to provide a method for controlling the rotation speed of a compressor in an air conditioner, which makes it possible to supply hot water at a stable water temperature.

[Summary of the invention]

The above-mentioned purpose is to connect a hot water supply heat exchanger to the discharge side pipe of the compressor of a refrigeration cycle equipped with a variable capacity compressor, and to connect a continuous water pipe inside the hot water supply heat exchanger. In an air conditioner in which the water flowing through the water pipe is inserted into the water supply heat exchanger and is heated by the water supply heat exchanger, water flowing through the water pipe and flowing into the water supply heat exchanger is heated. This is achieved by measuring the inlet temperature of the water and the outside air temperature, and controlling the rotation speed of the compressor based on the difference between the preset temperature and the inlet temperature and the outside air temperature.

[Embodiments of the invention]

The present invention will be explained below with reference to embodiments shown in the drawings.

In this embodiment, the compressor 1 is equipped with a frequency variable device 23, as shown in FIG. 7, so that the rotation speed of the compressor 1 can be changed. This frequency variable device 23 is connected to a control device 24 for controlling the rotation speed of the compressor 1, and this control device 24 has external temperature,
The inlet temperature of water flowing through the water pipe 21 and flowing into the hot water supply heat exchanger 20, and the water pipe 21
Temperature sensors 25, 26, and 27 are respectively provided to individually detect the outlet temperature of water flowing inside the hot water supply heat exchanger 20 and flowing out to the outside.

The rotation speed of the compressor 1 is controlled via the control device 24 based on the set water temperature input in advance to the control device 24, the outside temperature detected by the temperature sensor 25, and the water inlet temperature detected by the temperature sensor 26. In this way, hot water at the desired set water temperature can be obtained.

That is, curves A, B, and C in FIG. 6 show the relationship between the outside air temperature and the hot water temperature when the rotational speed of the compressor 1 is N, 2N, and 3N, respectively, and the curves C and D are as follows.
It shows the relationship between outside air temperature and hot water supply temperature when the inlet water temperature is 0°C and 10°C, respectively.

As is clear from this figure, the lower the outside temperature is, and the larger the difference between the set temperature and the inlet temperature, the more the rotation speed of the compressor 1 must be increased in order to obtain hot water at the desired set temperature. I know I need to raise it.

Therefore, the data shown in FIG. 6 is input into the control device 24 in advance, and this data is compared with the outside air temperature, as well as the difference between the set temperature and the inlet temperature. , Also, the larger the difference between the set temperature and the inlet temperature, the higher the rotation speed of the compressor 1 based on the data, and thereby,
The system is designed to provide hot water at the desired set water temperature.

As a result, the high-temperature gas refrigerant discharged from the compressor 1 is supplied to the hot water heat exchanger 20 during both cooling as shown in FIG. 4 and heating as shown in FIG. The water flowing through the 21 is rapidly heated, and hot water is supplied when you open the faucet.
At this time, as mentioned above, the rotation speed of the compressor 1 is rapidly increased according to the outside air temperature and the difference between the set temperature and the inlet temperature, shortening the time until the outlet water temperature changes and making it stable. can be controlled.

Note that this control requires a large capacity at the start of hot water supply, so it is desirable to operate the compressor 1 at the maximum rotation speed and perform this control after a predetermined period of time has elapsed.

Further, in this embodiment, a temperature sensor 27 for detecting the outlet temperature is provided, which compares the outlet temperature with a set temperature by switching it with a switch or the like, for example. This is to enable the rotation speed of the compressor 1 to be controlled in accordance with this temperature difference.

〔Effect of the invention〕

As described above, the present invention measures the inlet temperature and outside air temperature of water flowing through a water pipe and flowing into a hot water supply heat exchanger, and measures the difference between a preset set temperature and the inlet temperature. Since the rotation speed of the compressor of the air conditioner is controlled based on the above-mentioned outside air temperature, stable control is achieved by shortening the time from when the rotation speed of the compressor changes until the outlet temperature changes. As a result, the water flowing through the water pipes, heated by the hot water supply heat exchanger, and flowing out of the water pipe faucet is kept at a temperature close to the set temperature and at a stable water temperature. It has the effect of being able to do this.

[Brief explanation of drawings]

Figures 1, 2, and 3 are circuit diagrams showing conventional air conditioners in different modes, and Figures 4 and 5 are circuit diagrams showing existing air conditioners in different modes. , FIG. 6 is a graph showing the relationship between outside air temperature and hot water supply temperature, and FIG. 7 is an explanatory diagram showing the main part of the present invention. 1...Compressor, 3...Outdoor heat exchanger, 4...
Capillary tube, 5... Indoor heat exchanger, 7
... Four-way valve, 8 ... Check valve, 9 ... Liquid tank, 10 ... Expansion valve, 12 ... Hot water tank, 13,1
4... Heat exchanger for hot water storage, 15, 19... Bypass pipe line, 16, 17, 18... Three-way valve, 20... Heat exchanger for hot water supply, 21... Water pipe, 22... Open/close valve, 23 ... Frequency variable device, 24 ... Control device, 25, 26, 27 ... Temperature sensor.

Claims (1)

[Claims] 1. A hot water supply heat exchanger is connected to the discharge side pipe of the compressor of a refrigeration cycle equipped with a variable capacity compressor, a continuous water pipe is inserted into the inside of the hot water supply heat exchanger, and the above-mentioned In an air conditioner in which water flowing through a water pipe located inside the hot water supply heat exchanger is heated, the inlet temperature of the water flowing through the water pipe and flowing into the hot water supply heat exchanger. and an outside air temperature, and the rotation speed of the compressor is controlled based on the difference between a preset temperature and the inlet temperature, and the outside air temperature. Number control method.