CN205373189U - Low temperature heat pump system and air conditioner - Google Patents

Abstract

The utility model relates to the technical field of air conditioning, and in particular discloses a low-temperature heat pump system, which includes a main circuit composed of a compressor, a four-way valve, a condenser, an evaporator and an economizer, and an air injection enthalpy increasing circuit. The economizer has a second The inlet and outlet of the first refrigerant pipe and the inlet and outlet of the second refrigerant pipe, the inlet of the first refrigerant pipe is connected with the condenser through the refrigerant pipe, the outlet of the first refrigerant pipe is respectively connected with the evaporator, the inlet of the second refrigerant pipe and the air supply port of the compressor through the refrigerant pipe The outlet of the second refrigerant pipe communicates with the air supply port of the compressor through the refrigerant pipe. Meanwhile, an air conditioner with a low-temperature heat pump system is disclosed. Compared with the existing low-temperature heat pump system in which the refrigerant is directly injected from the economizer into the medium-pressure chamber of the compressor, the utility model further improves the displacement of the compressor, increases the input power of the compressor, and reduces the compression capacity. Ratio, which improves the operating reliability of the system in low temperature environment.

Description

Low temperature heat pump system and air conditioner

technical field

The utility model relates to the technical field of air conditioning, in particular to a low-temperature heat pump system and an air conditioner with the low-temperature heat pump system.

Background technique

At present, when the existing conventional heat pump water heater encounters low temperature conditions, the evaporation temperature of the system decreases, that is, the low pressure decreases, causing the compression ratio of the compressor to exceed the reliable range, which easily causes damage to important components such as the compressor. In order to ensure the reliability of the unit, generally choose not to start, or only heat the cold water to a lower temperature (that is, at the edge of the operating range of the compressor), and then replace it with electric auxiliary heating. In other words, the conventional heat pump system has low energy efficiency and consumes electricity at low temperatures, and it is difficult to guarantee the stability and reliability of the system.

Based on the above description, there is an urgent need for a low-temperature heat pump system and an air conditioner with the low-temperature heat pump system to solve the problems of poor stability and reliability of the existing heat pump system operating in a low-temperature environment and a large compression ratio of the compressor.

Utility model content

One of the purposes of the present utility model is to propose a low-temperature heat pump system to solve the problems of poor stability and reliability of the existing heat pump system in low-temperature environment and high compression ratio of the compressor.

The second purpose of the utility model is to provide an air conditioner with the above-mentioned low-temperature heat pump system.

For this purpose, the utility model adopts the following technical solutions:

The utility model proposes a low-temperature heat pump system, which includes a main circuit composed of a compressor, a four-way valve, a condenser, an evaporator and an economizer, and an air injection enthalpy increasing circuit. The economizer has a first refrigerant pipe inlet and outlet and The inlet and outlet of the second refrigerant pipe, the inlet of the first refrigerant pipe communicate with the condenser through the refrigerant pipe, the outlet of the first refrigerant pipe respectively communicates with the evaporator, the inlet of the second refrigerant pipe and the air supply port of the compressor through the refrigerant pipe, and the second refrigerant pipe The outlet communicates with the air supply port of the compressor through the refrigerant pipeline.

As a preferred solution of the low-temperature heat pump system, a first expansion valve is arranged on the refrigerant pipe connecting the outlet of the first refrigerant pipe and the evaporator.

As a preferred solution of the low-temperature heat pump system, the refrigerant pipe connecting the outlet of the first refrigerant pipe and the inlet of the second refrigerant pipe is provided with a first solenoid valve and a second expansion valve.

As a preferred solution of the low-temperature heat pump system, the second solenoid valve and the third expansion valve are arranged on the refrigerant pipe connecting the outlet of the first refrigerant pipe and the air supply port of the compressor.

As a preferred solution of the low-temperature heat pump system, the first expansion valve is an electronic expansion valve or a thermal expansion valve.

As a preferred solution of the low-temperature heat pump system, the second expansion valve is a thermal expansion valve or an electronic expansion valve.

As a preferred solution of the low-temperature heat pump system, the third expansion valve is a capillary or thermal expansion valve or an electronic expansion valve.

The utility model also proposes an air conditioner, including the above-mentioned low-temperature heat pump system.

The beneficial effects of the utility model are:

The utility model discloses a low-temperature heat pump system and an air conditioner. After passing through the economizer, the refrigerant returns to the economizer for heat absorption and evaporation, and then sprays into the medium-pressure chamber of the compressor. Compared with the medium-pressure cavity form of the direct injection into the compressor, the displacement of the compressor is increased, the input power of the compressor is increased, the compression ratio is reduced, and the operating reliability of the system in a low-temperature environment is improved. .

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings that need to be used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings in the following description are only the illustrations of the present invention. For some embodiments, those of ordinary skill in the art can also obtain other drawings according to the content of the embodiments of the present invention and these drawings without any creative effort.

Fig. 1 is a schematic structural diagram of a low-temperature heat pump system provided by Embodiment 1 of the present invention;

Fig. 2 is a flow chart of the control method of the low-temperature heat pump system provided by Embodiment 1 of the present invention.

1. Compressor; 2. Condenser; 3. First expansion valve; 4. Evaporator; 5. Economizer; 6. First solenoid valve; 7. Second expansion valve; 8. Four-way valve; 9. Second Two solenoid valves; 10. The third expansion valve;

detailed description

In order to make the technical problem solved by the utility model, the technical scheme adopted and the technical effect achieved clearer, the technical scheme of the embodiment of the utility model will be further described in detail below in conjunction with the accompanying drawings. Obviously, the described embodiment is only Some embodiments of the utility model, but not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without making creative efforts belong to the protection scope of the present utility model.

Preferred embodiment one

Fig. 1 is a schematic structural diagram of a low-temperature heat pump system provided in this embodiment. As shown in Figure 1, the low temperature control system proposed in this embodiment includes a main circuit and a gas injection enthalpy increasing circuit composed of a compressor 1, a four-way valve 8, a condenser 2, an evaporator 4 and an economizer 5, and the economizer 5 has The inlet and outlet of the first refrigerant pipe and the inlet and outlet of the second refrigerant pipe, the inlet of the first refrigerant pipe is connected with the condenser 2 through the refrigerant pipe, and the outlet of the first refrigerant pipe is respectively connected with the evaporator 4, the inlet of the second refrigerant pipe and the compressor through the refrigerant pipe The gas supply port of 1 is connected, and the outlet of the second refrigerant pipe is connected with the gas supply port of compressor 1 through the refrigerant pipeline.

Wherein, the compressor 1 is a low-temperature air injection enthalpy increasing compressor. A first expansion valve 3 is arranged on the refrigerant pipe connecting the outlet of the first refrigerant pipe and the evaporator 4 . A first solenoid valve 6 and a second expansion valve 7 are arranged on the refrigerant pipeline connecting the outlet of the first refrigerant pipe and the inlet of the second refrigerant pipe. A second solenoid valve 9 and a third expansion valve 10 are arranged on the refrigerant pipeline connecting the outlet of the first refrigerant pipeline and the air supply port of the compressor 1 . The first expansion valve 3 is an electronic expansion valve or a thermal expansion valve, and the second expansion valve 7 is a thermal expansion valve or an electronic expansion valve. In this embodiment, the first expansion valve 3 is preferably an electronic expansion valve, and the second expansion valve 7 is preferably a thermal expansion valve, which can ensure a certain degree of superheat of the refrigerant gas by adjusting the flow rate of the refrigerant. Considering the cost issue, the third expansion valve 10 is preferably a low-cost capillary tube. Of course, a thermal expansion valve or an electronic expansion valve can also be selected to achieve the throttling effect of the capillary tube.

When the low-temperature heat pump system is running normally, the refrigerant flows in the main circuit, and its flow path is: compressor 1-four-way valve 8-condenser 2-economizer 5-first expansion valve 3-evaporator 4-four-way valve 8 - Compressor 1. When the ambient temperature is low, the first solenoid valve 6 is opened, and the refrigerant flows in two paths, respectively the main loop path: compressor 1-four-way valve 8-condenser 2-economizer 5-first expansion valve 3- Evaporator 4-four-way valve 8-compressor 1 and gas injection enthalpy increasing circuit path: compressor 1-four-way valve 8-condenser 2-economizer 5-first solenoid valve 6-second expansion valve 7-economizer 5-compressor 1, wherein, after passing through the economizer 5, the refrigerant is throttled by the second expansion valve 7 and then returns to the economizer 5 for heat absorption and evaporation, and then injected into the medium-pressure chamber of the compressor 1, which is different from the existing The refrigerant of the low-temperature heat pump system is directly injected from the economizer 5 into the medium-pressure chamber of the compressor 1. Compared with the form, the displacement of the compressor 1 is increased, the input power of the compressor 1 is increased, and the compression ratio is reduced. The operating reliability of the system in a low temperature environment is improved, and at the same time, the utilization of the economizer 5 greatly improves the energy efficiency ratio of the system.

This embodiment proposes a control method for the above-mentioned low-temperature heat pump system, as shown in FIG. 2 , the control method for the low-temperature heat pump system in this embodiment includes the following steps:

A. Check whether the power-on conditions are met, and if so, enter step B, otherwise continue testing.

B. Turn on the compressor 1, run the main circuit for _t1 time until the refrigerant in the main circuit is almost in a steady state, open the first solenoid valve 6 and the second expansion valve 7, and run the gas injection enthalpy increasing circuit.

If the first solenoid valve 6 is opened when the system starts to operate the main circuit, then at this time the expansion valves of the main circuit and the gas injection enthalpy increasing circuit are adjusted at the same time, and the first expansion valve 3 of the main circuit is opened larger, the refrigerant in the main circuit The resistance is small and the refrigerant circulation is large, so the amount of refrigerant in the air injection enthalpy increasing circuit is small. At this time, when the pressure detection port and temperature sensing bag of the second expansion valve 7 of the air injection enthalpy increasing circuit detect that the amount of refrigerant is too small, The valve body will be mechanically opened to obtain the amount of refrigerant for the default superheat of the valve body. In this way, when the operation of the refrigerant in the main circuit is not stable, it will also involve the adjustment of the refrigerant in the air injection enthalpy circuit. It will lead to a longer period of refrigerant snatching.

Generally speaking, for a heat pump system using a suitable thermal expansion valve, it takes about _t1 time (generally 3-10 minutes) to achieve a relatively stable system during operation. The main circuit is operated at t1 time, so that the refrigerant in the main circuit runs close to a steady state, and then the first solenoid valve 6 of the air injection enthalpy increase circuit is opened, and a certain amount of refrigerant is allocated from the almost steady state main circuit to participate in the air injection increase. The refrigerant circulation of the enthalpy circuit plays the role of increasing enthalpy by gas injection.

C. Determine whether the exhaust gas temperature T _row is greater than the preset maximum exhaust gas temperature T _{row max} during the heating process, if yes, perform step D, otherwise, perform step F.

D. Open the second solenoid valve 9 and the third expansion valve 10, spray the supercooled refrigerant liquid directly into the medium-pressure chamber of the compressor 1, and reduce the discharge temperature T _row .

During the heating process, if the distribution of refrigerant in the main circuit is too small or the water temperature is heated to a certain temperature, it may cause the discharge temperature T _row to be greater than the preset maximum discharge temperature T _{row max} . At this time, the second solenoid valve is turned on. The valve 9 allows the condensed liquid to pass through the third expansion valve 10, and sprays the supercooled liquid directly into the medium-pressure chamber of the compressor 1 to reduce the discharge temperature and ensure the reliability of the compressor 1. After spraying liquid to compressor 1, go to step E.

E. Determine whether the exhaust gas temperature T _row is greater than the preset maximum exhaust temperature T _{row max} - the return difference ΔT _row of exhaust temperature drop, if yes, execute step D, otherwise, execute step F.

In this embodiment, the range of return difference ΔT _row for exhaust gas temperature drop is 3-15°C.

F. Heat the heat pump system to the set temperature and exit.

The low-temperature air injection enthalpy-increasing heat pump system adopting this control method will reach the required low-temperature operation state within t ₁ +(3-5)min.

The control method of the low-temperature heat pump system in this embodiment first ensures that the main circuit runs for _t1 time until the refrigerant in the main circuit is close to a steady state, and then operates the air injection enthalpy increase circuit, thereby avoiding the expansion valve of the main circuit and the air injection enthalpy increase circuit in the refrigerant During the snatching process, the adjustment range is too large or too small, which causes the two-way system to fail to reach a steady state for a long time, resulting in the problem that the heating capacity and heating efficiency are not significantly improved, thereby improving the reliability of the compressor.

This embodiment also proposes an air conditioner, which includes the above-mentioned low-temperature heat pump system.

Note that the above are only preferred embodiments of the present invention and the applied technical principles. Those skilled in the art will understand that the utility model is not limited to the specific embodiments described here, and various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the protection scope of the utility model. Therefore, although the utility model has been described in detail through the above embodiments, the utility model is not limited to the above embodiments, and can also include more other equivalent embodiments without departing from the concept of the utility model. The scope of the present invention is determined by the appended claims.

Claims (8)

1. A low-temperature heat pump system comprising a main circuit and an air injection enthalpy increasing circuit composed of a compressor (1), a four-way valve (8), a condenser (2), an evaporator (4) and an economizer (5), It is characterized in that the economizer (5) has the inlet and outlet of the first refrigerant pipe and the inlet and outlet of the second refrigerant pipe, the inlet of the first refrigerant pipe communicates with the condenser (2) through the refrigerant pipe, and the outlet of the first refrigerant pipe passes through the refrigerant pipe They are respectively connected with the evaporator (4), the inlet of the second refrigerant pipe and the air supply port of the compressor (1), and the outlet of the second refrigerant pipe is communicated with the air supply port of the compressor (1) through the refrigerant pipe. 2. The low-temperature heat pump system according to claim 1, characterized in that a first expansion valve (3) is arranged on the refrigerant pipe connecting the outlet of the first refrigerant pipe and the evaporator (4). 3. The low temperature heat pump system according to claim 2, characterized in that the refrigerant pipe connecting the outlet of the first refrigerant pipe and the inlet of the second refrigerant pipe is provided with a first solenoid valve (6) and a second expansion valve (7) . 4. The low-temperature heat pump system according to claim 1, characterized in that the second solenoid valve (9) and the third expansion valve are arranged on the refrigerant pipe connecting the outlet of the first refrigerant pipe and the air supply port of the compressor (1) (10). 5. The low temperature heat pump system according to claim 2 or 3, characterized in that the first expansion valve (3) is an electronic expansion valve or a thermal expansion valve. 6. The low-temperature heat pump system according to claim 3, characterized in that, the second expansion valve (7) is a thermal expansion valve or an electronic expansion valve. 7. The low-temperature heat pump system according to claim 4, characterized in that, the third expansion valve (10) is a capillary or thermal expansion valve or an electronic expansion valve. 8. An air conditioner, characterized by comprising the low-temperature heat pump system according to any one of claims 1-7.