CN109945292A - Dual heat source two-stage compression heat pump hot water system and method with auxiliary compressor - Google Patents

Abstract

The present disclosure proposes double heat source two stages of compression heat pump hot-water systems and method with auxiliary compressor, double heat source evaporators include air-source evaporator and soil source evaporator；The refrigerant of the air-source evaporator outlet reaches soil source evaporating pressure after the boosting of low-pressure stage compressor, and mixes with the refrigerant of soil source evaporator outlet, enters high pressure stage compressor together later；Hot water heating process is completed in the heat release in gas cooler of the compressed refrigerant of high pressure stage compressor, and refrigerant is flowed out from gas cooler enters gas-liquid separator after throttling；The vapor phase refrigerant of the gas-liquid separator outlet is directly over auxiliary compressor and is compressed to gas cooler pressure, and liquid phase refrigerant enters evaporator link, absorbs heat from air and soil respectively, recycles so as to form one.

Description

Dual heat source two-stage compression heat pump hot water system and method with auxiliary compressor

technical field

The present disclosure relates to the technical field of refrigeration, in particular to a dual heat source two-stage compression heat pump hot water system and method with an auxiliary compressor.

Background technique

In today's era, with the increasing improvement of people's living standards and the intensification of energy crisis, the rational and effective utilization of energy is the theme of today's world. In the residential and industrial and commercial fields, heat pump water heaters are the focus of application and research at this stage due to their advantages of good energy saving and mature technology. The heat pump system can convert low-grade energy in air or soil into water on the basis of consuming less high-grade energy, realizing the effective use of natural resources or waste heat, and is an effective method to reduce energy waste and improve energy utilization efficiency.

At present, the widely used heat pump systems are mostly air source heat pumps and soil source heat pumps. Air source heat pump is currently a hotspot due to its simple structure and convenient installation.

The inventor found in practical work that when the ambient temperature is low in winter, it is difficult for the air source heat pump to meet the large heat supply demand of commercial water heaters, for example. The ground source heat pump can provide a large heat supply, and the heating capacity is relatively stable. However, the installation and maintenance of ground source heat pumps are difficult, the economic investment is large, and there are high standards and restrictions on the construction of heat pump systems, which also add obstacles to its large-scale use.

To sum up, the traditional heat pump system is not efficient and has obvious shortcomings. Although it has a certain energy saving effect compared with traditional electric heating equipment, there is still a large room for improvement. When the heat pump system works at a lower ambient temperature, due to the high working pressure, the large throttling loss and the low energy efficiency, it is necessary to propose improvement measures. Therefore, optimizing and upgrading the heat pump system is the focus of current research.

SUMMARY OF THE INVENTION

One of the objectives of the embodiments of the present specification is to provide a dual heat source two-stage compression heat pump hot water system with an auxiliary compressor, which can absorb heat from air and soil at the same time, increasing the environmental adaptability of the system, and with auxiliary compression The system construction method of the two-stage compression and intercooling of the machine can greatly improve the energy efficiency ratio of the system and improve the energy utilization rate.

The embodiments of this specification provide a dual heat source two-stage compression heat pump hot water system with an auxiliary compressor, wherein the dual heat source evaporator includes an air source evaporator and a soil source evaporator;

The refrigerant at the outlet of the air source evaporator reaches the soil source evaporation pressure after being boosted by the low pressure stage compressor, and is mixed with the refrigerant at the outlet of the soil source evaporator, and then enters the high pressure stage compressor together;

The refrigerant compressed by the high-pressure stage compressor releases heat in the gas cooler to complete the hot water heating process, and the refrigerant flows out of the gas cooler and enters the gas-liquid separator after being throttled;

The gas-phase refrigerant at the outlet of the gas-liquid separator is directly compressed to the pressure of the gas cooler through the auxiliary compressor, and the liquid-phase refrigerant enters the evaporator link to absorb heat from the air and soil respectively, thereby forming a cycle.

The embodiments of this specification also provide a working method of a dual heat source two-stage compression heat pump hot water system with an auxiliary compressor, including:

The refrigerant at the outlet of the air source evaporator is boosted by the low pressure stage compressor to reach the soil source evaporation pressure, and mixed with the refrigerant at the outlet of the soil source evaporator, and then enters the high pressure stage compressor together;

The refrigerant compressed by the high-pressure stage compressor releases heat in the gas cooler to complete the hot water heating process, and the refrigerant flows out of the gas cooler and enters the gas-liquid separator after being throttled;

The gas-phase refrigerant at the outlet of the gas-liquid separator is directly compressed to the pressure of the gas cooler through the auxiliary compressor, and the liquid-phase refrigerant enters the evaporator link to absorb heat from the air and soil respectively, thus forming a cycle.

Compared with the prior art, the beneficial effects of the present disclosure are:

The gas entering the gas-liquid separator after being throttled for the first time in the technical solution of the present disclosure is separated and compressed to the pressure of the air cooler by the auxiliary compressor. The auxiliary compressor can achieve a high-efficiency compression process and improve the system efficiency.

The two-stage compression of the technical solution of the present disclosure can reduce the pressure ratio of each stage, so that each stage can achieve high-efficiency compression.

The dual heat source of the technical solution of the present disclosure can realize the stable operation of the system. For example, when the temperature is low in winter, more heat from the soil can be used, and when the temperature is high in summer, more heat from the air source can be used.

Description of drawings

The accompanying drawings that constitute a part of the present disclosure are used to provide further understanding of the present disclosure, and the exemplary embodiments of the present disclosure and their descriptions are used to explain the present disclosure and do not constitute an improper limitation of the present disclosure.

FIG. 1 is a system structure connection diagram of an embodiment of the present disclosure;

2 is a system pressure-enthalpy diagram of an embodiment of the disclosure;

In the figure, 1, air source evaporator; 2, low pressure stage compressor; 3, high pressure stage compressor; 4, gas cooler; 5, first throttle valve; 7, second throttle valve; 10, third Throttle valve; 6. Gas-liquid separator; 8. Soil source evaporator; 9. Internal heat exchanger; 11. Auxiliary compressor.

Detailed ways

It should be noted that the following detailed description is exemplary and intended to provide further explanation of the present disclosure. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

It should be noted that the terminology used herein is for the purpose of describing specific embodiments only, and is not intended to limit the exemplary embodiments according to the present disclosure. As used herein, unless the context clearly dictates otherwise, the singular is intended to include the plural as well, furthermore, it is to be understood that when the terms "comprising" and/or "including" are used in this specification, it indicates that There are features, steps, operations, devices, components and/or combinations thereof.

Example 1

This embodiment discloses a dual heat source two-stage compression heat pump hot water system with auxiliary compressor, including: soil source evaporator, air source evaporator, low pressure compressor, high pressure compressor, auxiliary compressor, internal heat exchanger, air source Liquid separators and gas coolers, etc. Air source and soil source evaporators can absorb heat from air source and soil source, respectively. The refrigerant at the outlet of the air source evaporator is boosted by the low pressure stage compressor to reach the evaporation pressure of the soil source, mixed with the refrigerant at the outlet of the soil source evaporator, and then enters the high pressure stage compressor together. The refrigerant _CO2 releases heat in the gas cooler to complete the hot water heating process. The refrigerant flows out of the gas cooler and enters the gas-liquid separator after being throttled. The gas-phase refrigerant at the outlet of the gas-liquid separator is directly compressed to the pressure of the gas cooler through the auxiliary compressor, and the liquid-phase refrigerant enters the evaporator link to absorb heat from the air and soil respectively, thus forming a cycle.

Dual-source evaporators are rarely used in small household heat pump water heaters, and are mostly single-source heat pumps. Because the dual evaporator system is more complex, the investment cost is higher. However, as the heating load of the system increases and the ambient temperature decreases, the dual-source heat pump can exert its good low temperature adaptability. Currently, the commonly used dual-source evaporator systems are mostly cascade systems of dual heat pump systems. The combination of the dual-source system and the two-stage compression system in the embodiments of the present disclosure can not only improve environmental adaptability, but also effectively improve the system energy efficiency ratio.

In this embodiment, as shown in FIG. 1 , the soil source evaporator 8 is a medium temperature evaporator, and the air source evaporator 1 is a low temperature evaporator. The saturated liquid refrigerant at the outlet of the low-temperature evaporator becomes superheated after absorbing heat through the internal heat exchanger 9, and then enters the low-pressure stage compressor 2 to be compressed to the evaporation pressure corresponding to the evaporation temperature of the soil source, and then matches with the outlet of the medium-temperature evaporator. The saturated refrigerant is mixed, and then enters the high-pressure stage compressor 3 to be compressed to the air cooler pressure, the refrigerant at the outlet of the high-pressure compressor is mixed with the refrigerant at the outlet of the auxiliary compressor 11, and enters the gas cooler 4 to release heat, to generate the required heat. The refrigerant at the outlet of the air cooler is throttled to the intermediate pressure through the throttling valve 5, and then enters the gas-liquid separator 6. The gas at the outlet of the gas-liquid separator directly enters the auxiliary compressor and is boosted to the air-cooler pressure.

In this embodiment, the soil source evaporator 8 is a medium temperature evaporator, and the air source evaporator 1 is a low temperature evaporator, because in a winter environment, the soil source temperature will be significantly higher than the air source temperature. A dual heat source heat pump system can be combined with a two-stage compression system at different evaporation pressures.

The saturated liquid refrigerant at the outlet of the low-temperature evaporator becomes superheated after absorbing heat through the internal heat exchanger 9, and then enters the low-pressure stage compressor 2 and is compressed to the evaporation pressure corresponding to the evaporation temperature of the soil source, so that the outlet of the low-pressure stage compressor is compressed. The pressure is the same as the evaporation pressure corresponding to the soil source temperature, which can satisfy the isobaric mixing of the two fluids. And the thermodynamic process of two-stage compression and intermediate cooling can be realized after mixing.

Since the system is in transcritical operation, the air cooler pressure is a pressure range above the critical pressure of carbon dioxide, and as the pressure increases, the temperature of the refrigerant at the compressor outlet also increases. In actual operation, the optimization analysis should be carried out according to the operating conditions.

Because the state of the refrigerant at the outlet of the air cooler is supercritical, it becomes a two-phase state after being throttled by the throttle valve, and then part of it enters the auxiliary compressor after passing through the gas-liquid separator, and part flows into the evaporator.

After throttling, the pressure of the refrigerant decreases and the temperature decreases, which can then reach the evaporation pressure corresponding to the soil source or air source evaporator, and has enough cooling capacity to absorb heat from the outside to complete the entire cycle process.

In this embodiment, as shown in FIG. 2 , the liquid at the outlet of the gas-liquid separator is divided into two parts, and one part enters the soil source evaporator to absorb heat after being enthalpy throttling to the medium temperature evaporation pressure through the throttle valve 7 The temperature is raised to a saturated gaseous state; the other part, the temperature is reduced to a subcooled state after the heat is released by the internal heat exchanger 9, and then the enthalpy is throttled to the low-temperature evaporation pressure through the throttle valve 10, and then enters the low-temperature evaporator to absorb heat to saturation gaseous. After the above process, a complete cycle is formed. When the external ambient temperature is high, more refrigerant can enter the air source evaporator 1 to absorb heat, and when the temperature is low in winter, more refrigerant can enter the soil source evaporator 8 to absorb heat, thereby achieving system stability. Efficient operation.

The system consists of a dual evaporator system combined with a two-stage compression system, with the addition of an auxiliary compressor. The two evaporators in this system can absorb heat from the air source and the soil source respectively, because the temperature of the air source and the soil source are different, so the two evaporators in the system can work at different evaporation pressures respectively, which provides conditions under which the system can be combined with a two-stage compression system. The dual heat source system can improve the environmental adaptability and stability of the system, and the two-stage compression system can effectively improve the energy efficiency ratio of the system. In addition, the auxiliary compressor added to the system can effectively share the power consumption of the high-pressure compressor with the highest load, increase the life of the compressor, and further improve the performance of the system.

In the above embodiment, the refrigerant may be CO ₂ medium, but it is not limited to this medium, and other mediums are also within the protection scope of the present disclosure as long as they can operate in the system.

Example 2

This embodiment discloses a working method of a dual heat source two-stage compression heat pump hot water system with an auxiliary compressor, including:

The low-temperature evaporator starts to work, and the saturated liquid refrigerant at the outlet of the low-temperature evaporator becomes superheated after absorbing heat through the internal heat exchanger 9;

Then the superheated refrigerant enters the low-pressure stage compressor 2, controls the operation of the low-pressure stage compressor, compresses the superheated refrigerant to the evaporation pressure corresponding to the evaporation temperature of the soil source, and then compresses the refrigerant to the required pressure with the soil. The saturated refrigerant at the outlet of the source evaporator 8 is mixed;

The mixed refrigerant then enters the high-pressure stage compressor, controls the high-pressure stage compressor 3 to work, compresses the mixed refrigerant, and compresses it to the working pressure of the gas cooler;

The refrigerant at the outlet of the high pressure compressor is mixed with the refrigerant at the outlet of the auxiliary compressor 11 and enters the gas cooler 4 where heat is released to generate the required heat. The refrigerant at the outlet of the gas cooler 4 is throttled to the intermediate pressure through the throttle valve 5 with constant enthalpy, and then enters the gas-liquid separator 6 .

The gas at the outlet of the gas-liquid separator directly enters the auxiliary compressor and is boosted to the air-cooler pressure. The liquid at the outlet of the gas-liquid separator is divided into two parts. One part is throttled to the medium temperature evaporation pressure by the throttle valve 7, and then enters the soil source evaporator to absorb heat and heat up to a saturated gas state; the other part passes through the internal heat exchanger. 9. After the heat is released, the temperature is reduced to a supercooled state, and then the throttle valve 10 is enthalpy throttling to the low-temperature evaporation pressure, and then enters the low-temperature evaporator to absorb heat to a saturated gas state. After the above process, a complete cycle is formed.

Example three

This embodiment discloses a control system for a dual heat source two-stage compression heat pump hot water system with an auxiliary compressor. The control system includes a controller, which is respectively connected with the air source evaporator, the low-pressure stage compressor, and the high-pressure stage compressor. , gas cooler, first throttle valve 5, second throttle valve 7, third throttle valve 10, gas-liquid separator, soil source evaporator, internal heat exchanger 9, auxiliary compressor are connected to control The working status of the connected device.

With the different operating conditions of the system, the air cooler pressure and intermediate throttle pressure in the system will also change constantly. When the pressure of the air cooler increases, the ability to prepare high-temperature hot water will also increase, but the COP of the system will decrease, so it is necessary to find the optimal pressure value according to the working conditions.

In addition, when the air temperature changes, the refrigerant flow ratio into the soil source and air source evaporator should also change. For example, when the air temperature is too low, the soil source evaporator should be used to a greater extent to meet the corresponding heat load demand. However, when the air temperature rises so that it is greater than the soil source temperature, because the actual installation capacity of the soil source evaporator is limited and the maintenance cost is high, all the refrigerants should enter the air source evaporator at this time, and increase the system performance.

In application, the dual heat source two-stage compression heat pump hot water system with auxiliary compressor is applied in the field of commercial water heaters.

It is to be understood that, in the description of this specification, referring to the description of the terms "an embodiment", "another embodiment", "other embodiment", or "the first embodiment to the Nth embodiment" etc. means A particular feature, structure, material, or characteristic described in connection with this embodiment or example is included in at least one embodiment or example of the present disclosure. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials and characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The above descriptions are only preferred embodiments of the present disclosure, and are not intended to limit the present disclosure. For those skilled in the art, the present disclosure may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present disclosure shall be included within the protection scope of the present disclosure.

Claims (10)

1. the dual heat source two-stage compression heat pump hot water system with auxiliary compressor, it is characterized in that, described dual heat source evaporator comprises air source evaporator and soil source evaporator; The refrigerant at the outlet of the air source evaporator reaches the soil source evaporation pressure after being boosted by the low pressure stage compressor, and is mixed with the refrigerant at the outlet of the soil source evaporator, and then enters the high pressure stage compressor together; The refrigerant compressed by the high-pressure stage compressor releases heat in the gas cooler to complete the hot water heating process, and the refrigerant flows out of the gas cooler and enters the gas-liquid separator after being throttled; The gas-phase refrigerant at the outlet of the gas-liquid separator is directly compressed to the pressure of the gas cooler through the auxiliary compressor, and the liquid-phase refrigerant enters the evaporator link to absorb heat from the air and soil respectively, thereby forming a cycle. 2. The dual heat source two-stage compression heat pump hot water system with auxiliary compressor as claimed in claim 1, wherein the saturated liquid refrigerant at the outlet of the air source evaporator becomes superheated after absorbing heat through the internal heat exchanger , and then into the low-pressure stage compressor. 3. The dual heat source two-stage compression heat pump hot water system with an auxiliary compressor according to claim 1, wherein an auxiliary compressor is arranged on the pipeline between the gas-liquid separator and the gas cooler, and the high-pressure compression The refrigerant at the outlet of the compressor mixes with the refrigerant at the outlet of the auxiliary compressor and enters the gas cooler to release heat. 4. The dual heat source two-stage compression heat pump hot water system with auxiliary compressor as claimed in claim 1, wherein the liquid-phase refrigerant enters the evaporator link, and a part is throttled to the middle temperature evaporation pressure through the throttling valve etc. After that, it enters the soil source evaporator to absorb heat and heat up to the saturated gas state; the other part, after the heat is released by the internal heat exchanger, the temperature is reduced to the supercooled state, and then the enthalpy is throttled to the low temperature evaporation pressure through another throttle valve, and then Enter into the low temperature evaporator, absorb heat to a saturated gas state. 5. The working method of the dual heat source two-stage compression heat pump hot water system with auxiliary compressor is characterized in that, comprising: The refrigerant at the outlet of the air source evaporator is boosted by the low pressure stage compressor to reach the soil source evaporation pressure, and mixed with the refrigerant at the outlet of the soil source evaporator, and then enters the high pressure stage compressor together; The refrigerant compressed by the high-pressure stage compressor releases heat in the gas cooler to complete the hot water heating process, and the refrigerant flows out of the gas cooler and enters the gas-liquid separator after being throttled; The gas-phase refrigerant at the outlet of the gas-liquid separator is directly compressed to the pressure of the gas cooler through the auxiliary compressor, and the liquid-phase refrigerant enters the evaporator link to absorb heat from the air and soil respectively, thus forming a cycle. 6. The working method of the dual heat source two-stage compression heat pump hot water system with auxiliary compressor according to claim 5, wherein the saturated gaseous refrigerant at the outlet of the controlled air source evaporator enters the internal heat exchanger to absorb heat and After absorbing heat, it becomes superheated, and then enters the superheated refrigerant to be sent to the low-pressure stage compressor. 7. The dual heat source two-stage compression heat pump hot water system with auxiliary compressor as claimed in claim 5, wherein the refrigerant at the outlet of the high pressure compressor is mixed with the refrigerant at the outlet of the auxiliary compressor, and enters the gas Heat is released in the cooler. 8. The working method of the dual heat source two-stage compression heat pump hot water system with auxiliary compressor as claimed in claim 5, characterized in that, before the liquid-phase refrigerant enters the evaporator link, a part of it passes through the throttling valve and other enthalpy throttling. After reaching the medium temperature evaporating pressure, it enters the soil source evaporator to absorb heat and heat up to a saturated gas state; the other part, after the heat is released by the internal heat exchanger, the temperature is reduced to a supercooled state, and then it is enthalpy throttled to a low temperature through another throttle valve. Evaporation pressure, and then into a low temperature evaporator, absorbing heat to a saturated gas state. 9. The working method of the dual heat source two-stage compression heat pump hot water system with auxiliary compressor as claimed in claim 5, characterized in that, when the external ambient temperature is higher, relatively more refrigerant enters the air source evaporator Absorb heat, and when the temperature is low in winter, relatively more refrigerant enters the soil source evaporator to absorb heat. 10. A control system based on the dual heat source two-stage compression heat pump hot water system with auxiliary compressor according to any one of claims 1-4, the control system comprises a controller, the controller is respectively connected with the air source evaporator, the low pressure Stage compressor, high pressure stage compressor, gas cooler, throttle valve, gas-liquid separator, soil source evaporator, internal heat exchanger, auxiliary compressor are connected to control the working state of the connected equipment.