KR100484870B1 - Driving control method for a heat pump system - Google Patents

Abstract

The present invention relates to an operation control method of a heat pump system, and in particular, a first step of operating at least one or more of the plurality of compressors so that the capacity varies according to the cooling / heating load, and the compressor is operated in the first step In the case where the current superheat degree T is measured during the set time t and the current superheat degree error, which is a difference between the current superheat degree T measured in the second step and the target target superheat degree To, The third step of adjusting the opening value of the electromagnetic expansion valve to the target opening value Po set according to Te and the capacity of the compressor to be operated is performed. By adjusting the opening value of the electronic expansion valve so that the current superheat is kept constant, the heat pump system can be operated stably to increase cooling or heating efficiency.

Description

Operation control method for heat pump system {Driving control method for a heat pump system}

The present invention relates to an operation control method of a heat pump system including a plurality of compressors, and in particular, by adjusting the opening value of the electronic expansion valve to adjust the flow rate of the refrigerant circulated as the capacity of the operated compressor is changed, the current superheat degree. It is related to the operation control method of the heat pump system to maintain a constant so that the heat pump system to operate stably to increase the cooling or heating efficiency.

In general, the heat pump system has a refrigerant circulated along the compressor, the condenser, the expansion device, and the evaporator, and the outdoor heat exchanger and the indoor heat exchanger respectively installed on the outdoor side and the indoor side during cooling function as the condenser and the evaporator, respectively. During the heating, the outdoor heat exchanger and the indoor heat exchanger each serve as an evaporator and a condenser.

1 is a configuration diagram showing a state of cooling of the heat pump system according to the prior art.

In the conventional heat pump system, as illustrated in FIG. 1, the compressor 2 compresses the refrigerant into a gas refrigerant having a high temperature and high pressure, and the refrigerant compressed by the compressor 2 has a medium temperature and high pressure. An outdoor heat exchanger (4) for condensing with liquid refrigerant, an electromagnetic expansion valve (6) for reducing the refrigerant condensed in the outdoor heat exchanger (4) with a low temperature low pressure refrigerant, and a pressure reduction in the electromagnetic expansion valve (6) Indoor heat exchanger (8) for evaporating refrigerant to low-temperature low-pressure gas refrigerant, the accumulator (10) installed at the front end of the compressor (2) to filter the liquid refrigerant and the rear end of the compressor (2) during cooling / heating It consists of a four-way valve 12 for switching the flow of the refrigerant, the operation of the heat pump system is controlled by a microcomputer (not shown).

When the heat pump system is cooled and operated as described above, the refrigerant is circulated along the compressor 2, the outdoor heat exchanger 4, the electromagnetic expansion valve 6, the indoor heat exchanger 8, and the outdoor heat exchanger 4. And the indoor heat exchanger 8 serve as condensers and evaporators, respectively.

However, when the refrigerant flow is switched by the four-way valve 12 to heat the heat pump system, the refrigerant is a compressor (2), an indoor heat exchanger (8), an electronic expansion valve (6), an outdoor heat exchanger (4). The indoor heat exchanger 8 and the outdoor heat exchanger 4 serve as condensers and evaporators, respectively.

At this time, the electronic expansion valve 6 is usually adjusted to the opening value in the range of 0 to 500 pulse or 0 to 1000 pulse to adjust the flow rate of the refrigerant in accordance with the cooling or heating load, the opening degree is the current superheat ( T) is adjusted to be the target degree of superheat To.

Here, the current superheat degree (T) is a difference value between the piping temperature of the suction side of the compressor 2 and the piping temperature of the indoor heat exchanger 4 when cooling, and the suction of the compressor 2 when heating. The difference between the side pipe temperature and the outdoor heat exchanger 8 side pipe temperature is measured and calculated every set time, and the target superheat degree To is input to the microcomputer in advance in consideration of the capacity of the compressor 2. have.

As described above, in the heat pump system of the related art, since only one compressor is applied, the opening value of the electromagnetic expansion valve is adjusted such that the current superheat degree is set to a target superheat degree considering the capacity of the compressor.

However, recently, as the heat pump system is enlarged, a plurality of compressors are applied, and the capacity of the compressor in which at least one compressor is selectively operated and operated is changed according to the cooling or heating load of the plurality of compressors. If the opening value of the electronic expansion valve is adjusted without considering the capacity change of the compressor, there is a limit in quickly eliminating the cooling / heating load and there is a problem in that the compressor is overheated.

The present invention has been made to solve the above-mentioned problems of the prior art, and when the at least one compressor is operated during cooling or heating operation, the opening value of the electronic expansion valve is set according to the current superheat error and the capacity of the compressor to be operated. The purpose of the present invention is to provide a method of controlling the operation of a heat pump system capable of quickly eliminating cooling / heating loads by adjusting to a target opening value and preventing overheating of the compressor.

The operation control method of the heat pump system according to the present invention for solving the above problems is the first step of operating at least one or more of the plurality of compressors to vary the capacity according to the cooling / heating load, and in the first step When the compressor is operated, the second step in which the current superheat degree T is measured during the set time t, and the difference between the current superheat degree T measured in the second step and the target target superheat degree To, A third step of adjusting the opening value of the electromagnetic expansion valve to the target opening value Po set according to the current superheat degree error Te and the capacity of the compressor operating, wherein the first step is the first, At least one compressor of the two compressors is operated, and in the second step, the set time t is a time at which the current superheat degree T is measured more than once.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a configuration diagram showing a cooling state of the heat pump system according to the present invention, Figure 3 is a flow chart showing the operation control method of the heat pump system according to the present invention.

When the heat pump system according to the present invention is described with reference to the cooling time as shown in Figure 2, a plurality of compressors (52a, 52b) for compressing, condensing, expanding, evaporating the refrigerant, and the outdoor heat exchanger (54) And an accumulator 60 and a plurality of compressors 52a and 52b installed at the tip of the electromagnetic expansion valve 56, the indoor heat exchanger 58, and the plurality of compressors 52a and 52b to filter the liquid refrigerant. Four-way valve 62 is installed at the rear end to switch the flow of the refrigerant during cooling or heating is installed to be connected to each other by the refrigerant pipe, the heat pump system is controlled by a microcomputer (not shown), the operation The microcomputer adjusts the opening value of the electronic expansion valve 56 to a target opening value Po set according to the current superheat error and the capacity of the compressor operated during cooling or heating operation.

When the heat pump system is cooled, the refrigerant is circulated along the plurality of compressors 52a and 52b, the outdoor heat exchanger 54, the electronic expansion valve 56, and the indoor heat exchanger 58. While the heat exchanger 54 and the indoor heat exchanger 58 serve as condensers and evaporators, respectively, when the refrigerant flow is switched by the four-way valve 62 so that the heat pump system is heated, the refrigerant may be a plurality of compressors. 52a, 52b, indoor heat exchanger 58, electronic expansion valve 56, and outdoor heat exchanger 54 are circulated along the heat exchanger 58 and the outdoor heat exchanger 54, respectively, the condenser and the evaporator Play a role.

In particular, the plurality of compressors (52a, 52b) is composed of first and second compressors (52a, 52b) having different capacities, the first compressor (52a) is more capacity than the second compressor (52b). The first and second compressors 52a and 52b are operated simultaneously when the cooling / heating load is relatively large, and the first and second compressors 52a and 52b are simultaneously operated when the cooling / heating load is relatively small. Only the compressor is running.

Because, when only one compressor is operated, the second compressor 52b is operated during cooling, while the first compressor 52a is operated during heating, which means that the user's sensation level due to the temperature change during heating is greater than that of cooling. Because it is sensitive.

Next, the electronic expansion valve 56 may control the opening and closing degree of the flow path so as to not only reduce the pressure of the refrigerant but also adjust the flow rate of the refrigerant, and this opening value is operated by the current superheat degree error Te in the microcomputer. The target opening value Po calculated by the capacity of the compressor is adjusted.

Specifically, the target opening value Po is selected according to the current superheat error Te calculated in the state in which the heat pump system is operated and the capacity of the operated compressor, and the opening degree increase / decrease value is selected. (Pe) is applied to a general control formula and calculated.

Here, the current superheat degree error Te is a difference value between the current superheat degree T and the target superheat degree To, and the current superheat degree T is the first and second compressors 52a and 52b during cooling. Is the temperature difference between the suction side pipe temperature and the indoor heat exchanger 54 side pipe temperature, and when heating, the suction side pipe temperature of the first and second compressors 52a and 52b and the outdoor heat exchanger 58 side pipe. The temperature difference value is measured and calculated for each set time, and the target superheat degree To is previously input to the microcomputer in consideration of the capacities of the compressors 52a and 52b.

The opening degree increase / decrease value Pe is selected from a table previously input to the microcomputer, and the target opening value Po is calculated by being applied to a control formula common to the microcomputer.

Operation control method of the heat pump system according to the present invention configured as described above with reference to Figure 3, the first step is the cooling / heating mode is selected by the user, at least one compressor according to the cooling / heating load (See S1, S2)

Here, when the heat pump system is cooled, the refrigerant is circulated along the plurality of compressors 52a and 52b, the outdoor heat exchanger 54, the electromagnetic expansion valve 56, and the indoor heat exchanger 58, and the heating operation is performed. Refrigerant is circulated along the plurality of compressors (52a, 52b), indoor heat exchanger (58), electronic expansion valve (56), outdoor heat exchanger (54).

In the second stage, the current superheat degree T is measured two times in succession during the set time t while the compressor is operated in the first stage, and each of the current superheat degree T and the target superheat degree To The first and second current superheat errors Te ₁ and Te ₂ , which are difference values, are calculated (see S3 and S4).

At this time, the set time (t) is a time taken while the current superheat degree T is measured twice. Usually, the current superheat degree T is measured once every 30 seconds.

In the third step, the _first and second degree increase and decrease values Pe ₁ and Pe ₂ are selected according to the _first and second current superheat errors Te ₁ and Te ₂ calculated in the second step and the capacity of the operated compressor. (See S5).

In detail, the first and second degree increase / decrease values Pe ₁ and Pe ₂ are _first calculated when the plurality of compressors are composed of the first and second compressors 52a and 52b which occupy 60% and 40% of the total capacity. According to the current superheat error (Te ₁ , Te ₂ ), it is selected from the following [Table 1] and [Table 2] when cooling / heating.

TABLE 1

Current superheat error (Te) Opening degree increase / decrease value (Pe) First and second compressor operation Second compressor operation 4 <Te 5 3 3 <Te ≤4 4 2 2 <Te ≤3 3 One 1 <Te ≤2 2 One 0.5 <Te ≤1 One 0 -0.5 <Te ≤0.5 0 0 -1 <Te ≤-0.5 -One 0 -2 <Te ≤-1 -2 -One -3 <Te ≤-2 -3 -One -4 <Te ≤-3 -4 -2 -7 <Te ≤-4 -5 -3 Te ≤-7 -15 -10

TABLE 2

Current superheat error (Te) Opening degree increase / decrease value (Pe) First and second compressor operation 1st compressor operation 4 <Te 5 3 3 <Te ≤4 4 2 2 <Te ≤3 3 One 1 <Te ≤2 2 One 0.5 <Te ≤1 One 0 -0.5 <Te ≤0.5 0 0 -1 <Te ≤-0.5 -One 0 -2 <Te ≤-1 -2 -One -3 <Te ≤-2 -3 -One -4 <Te ≤-3 -4 -2 -7 <Te ≤-4 -5 -3 Te ≤-7 -15 -10

As shown in [Table 1] and [Table 2] as described above, it is understood that the opening degree increase / decrease value Pe is set to be larger as the current superheat error Te is greater, and the capacity of the operated compressor is larger. Can be.

In the fourth step, the target opening value Po is calculated based on the _first and second opening and closing values Pe ₁ and Pe ₂ selected in the third step (see S6).

Here, the target opening degree value Po is calculated by applying the _first and second degree increase and decrease values Pe ₁ and Pe ₂ to Equation 1 below.

At this time, the Kp and Kd is a constant determined by the capacity of the compressor to operate and whether the cooling / heating.

In the fifth step, the opening value of the electromagnetic expansion valve 56 is adjusted to be the target opening value Po calculated in the fourth step (see S7).

Accordingly, the opening value of the electromagnetic expansion valve 56 is set according to the current superheat degree error Te, which is a difference between the current superheat degree T and the target superheat degree To, and the capacity of the compressor operated. Since the refrigerant flow rate can be adjusted according to the Po), the refrigerant flow rate can be appropriately responded to the cooling or heating load, and the refrigerant flow rate is less than the capacity of the operated compressor, thereby preventing the compressor from overheating.

In the operation control method of the heat pump system according to the present invention configured as described above, when at least one compressor is operated during cooling or heating operation, the opening degree is increased or decreased according to the current superheat degree error and the capacity of the operated compressor. After the target opening value is calculated according to the opening and closing value, the opening value of the solenoid expansion valve is adjusted to the target opening value, so that the cooling and heating load can be quickly responded to, thus providing a comfortable cooling and heating. Since it is possible to prevent overheating in advance, there is an advantage that can ensure the reliability of the compressor operation.

1 is a configuration diagram showing a state of cooling of the heat pump system according to the prior art,

2 is a configuration diagram showing a state of cooling of the heat pump system according to the present invention,

3 is a flowchart illustrating an operation control method of a heat pump system according to the present invention.

<Explanation of symbols on main parts of the drawings>

52a, 52b: first and second compressors 56: electromagnetic expansion valve

Claims (5)

A first step in which at least one of the plurality of compressors is operated so that the capacity varies according to the cooling / heating load; A second step in which a current superheat degree T is measured during a set time t when the compressor is operated in the first step; Electronic expansion with a target opening value Po set according to the current superheat degree error Te, which is a difference between the current superheat degree T measured in the second step and the set target superheat degree To, and the capacity of the compressor operating. The third step of adjusting the opening value of the valve, In the first step, at least one or more compressors of the first and second compressors having different capacities are operated. In the second step, the set time (t) is an operation control method of the heat pump system, characterized in that the current superheat degree (T) is measured more than once. delete delete The method of claim 1, The third step may include a first process of calculating a current superheat error Te that is a difference between a current superheat degree T measured in the second step and a target target superheat degree To; A second process of selecting an opening degree increase / decrease value Pe according to a current superheat error Te calculated in the first process and a capacity of an operated compressor; And a third process of calculating a target opening value Po according to the opening degree increase / decrease value Pe selected in the second process. The method of claim 4, wherein In the second process, the opening degree increase / decrease value Pe is selected from a table in which the opening degree increase / decrease value is stored according to the current superheat degree error Te and the capacity of the operated compressor.