CN110793230A - Large-temperature span high-temperature heat pump system - Google Patents

Abstract

A large temperature span high temperature heat pump system, including a low pressure stage compression subsystem, a first high pressure stage condensation temperature system and a second high pressure stage condensation temperature system, the low pressure stage compression subsystem includes a first compressor, a gas-liquid separator, a first Throttle component, evaporator, first regenerator, third regenerator, second regenerator, first high pressure stage condensing temperature system including second compressor, first condenser, third regenerator and first Two throttling components, the second high-pressure stage condensing temperature system includes a third compressor, a second condenser, a second regenerator and a third throttling component. The high and low pressure two-stage compression method is used to solve the problem that the single-stage compression ratio of the high-temperature heat pump is too large, which leads to the low heating efficiency. The heating performance of the heat pump system achieves the purpose of saving high-grade electric energy. Combined with the regenerative technology, the system makes full use of low-grade heat energy and reduces the energy consumption of the compressor.

Description

A large temperature span high temperature heat pump system

technical field

The invention belongs to the technical field of heat pumps, and in particular relates to a large temperature span high temperature heat pump system.

Background technique

High-temperature heat pump technology is a technology that converts low-grade thermal energy such as solar energy, industrial waste heat, or groundwater sources into high-temperature hot water or steam at around 120°C. Due to the high condensing temperature and the large temperature difference between the condensing temperature and the evaporating temperature, the traditional single-stage compression heat pump cycle has the characteristics of high compressor compression ratio, low compressor volume efficiency and low unit performance. In the two-stage compression intermediate incomplete cooling cycle, the low-pressure refrigerant vapor generated in the evaporator is first sucked into the low-pressure compressor for adiabatic compression to the intermediate pressure of the system, and then the refrigerant vapor is further compressed to the condensing pressure. The use of two-stage compression heat pump cycle further reduces the compression ratio of the low-pressure stage compressor and the high-pressure stage compressor, and further improves the volumetric efficiency of the compressor itself. high, the performance of the unit has been improved. However, with the application of high temperature heat pump technology, the condensation temperature required for production continues to increase, the heat transfer temperature difference in the condensation process continues to increase, and the cycle performance decreases, which severely limits the development of the high temperature heat pump field. In recent years, in order to improve the system performance of high temperature heat pump cycle, researchers have done a lot of work in refrigerant replacement, improvement of refrigeration cycle system and so on.

High-temperature heat pump technology is a method of using low-grade solar energy or other waste heat and waste heat, relying on compressors to adiabatically compress low-temperature and low-pressure refrigerant vapor to high-temperature and high-pressure refrigerant at the required condensing temperature to produce high-temperature hot water or steam. technology. The high-temperature heat pump technology is generally realized by using the compression heat pump cycle. It is generally believed that the exhaust temperature of the compressor does not exceed 70 °C. The density is reduced, and the working efficiency of the unit is reduced. When the compression ratio of the compressor reaches a certain value, it will cause the compressor to stop running, so the compression ratio of the compressor cannot be too high.

In order to reduce the compression ratio of the compressor and obtain a higher condensing temperature, the two-stage compression cycle was invented. When the high temperature hot water or steam is left and right, due to the large heat transfer temperature difference and the high compression ratio of the two-stage compressor, the performance of the system is also reduced, so that the two-stage compression heat pump cannot break through the higher heating temperature. The prior art discloses a piston-type high-temperature heat pump device for waste heat recovery, which improves the working efficiency of the unit, but this high-temperature heat pump cycle still does not solve the problem of excessive heat transfer temperature difference on the condenser side and excessive compression ratio of the compressor. The performance of the unit still needs to be improved.

In view of the above, how to use high temperature heat pump technology to produce high temperature hot water or steam, while reducing the compressor compression ratio, reducing the system heat transfer temperature difference, and improving the system heat pump cycle efficiency, has become a technical problem that the industry is concerned about and expects to solve.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a large temperature span high temperature heat pump system, the system uses the high and low pressure two-stage compression method to solve the problem that the compression ratio of the single-stage compression in the high temperature heat pump is too large and causes the heating efficiency to be low. The double condensing temperature solves the heating problem of large temperature span, and the heating performance of the heat pump system is improved by constructing the cascade heating heat pump cycle to achieve the purpose of saving high-grade electric energy. Combined with the regenerative technology, the system makes full use of low-grade heat energy. At the same time, the energy consumption of the compressor is reduced. The invention provides a cascade heating large temperature span high temperature heat pump system, which achieves the purpose of improving the energy efficiency of the unit, saving energy and protecting the environment, and meeting the demand for high temperature hot water or steam in life or production.

The technical scheme of the present invention is: a large temperature span high temperature heat pump system, comprising a low pressure stage compression subsystem, a first high pressure stage condensation temperature system and a second high pressure stage condensation temperature system, wherein the low pressure stage compression subsystem includes serially connected The first compressor, the gas-liquid separator, the first throttling component, the evaporator, the first regenerator, the third regenerator, and the second regenerator, the first high-pressure stage condensing temperature system includes serially connected A second compressor, a first condenser, a third regenerator and a second throttling component, the second high pressure stage condensing temperature system includes a third compressor, a second condenser, a second regenerator and a third a throttling component, the second throttling component and the third throttling component are connected in parallel with the gas-liquid separator;

The saturated refrigerant vapor generated after the external medium enters the evaporator enters the first regenerator for superheating and is divided into two paths, one of which flows into the second regenerator for secondary superheating, and then passes through the third regenerator. The throttling part enters the gas-liquid separator, and the other way flows into the third regenerator for secondary superheating, and the refrigerant vapor after secondary superheating is mixed and sucked by the first compressor; the gas-liquid separator The refrigerant wet vapor inside is divided into two parts, one part is generated as saturated refrigerant vapor mixed with the superheated refrigerant vapor generated by the first compressor and flows out, and the other part is generated as saturated refrigerant liquid and flows into the first regenerator to be passed through. After being subcooled, it enters the first throttling component for adiabatic throttling, and then flows into the evaporator, where heat exchange occurs with the low-grade and low-temperature heat source, and the wet refrigerant vapor evaporates and absorbs heat to become saturated refrigerant vapor.

Further optimization, the refrigerant wet vapor in the gas-liquid separator and the superheated refrigerant vapor generated by the first compressor are divided into two paths when they flow out, one of which is sucked by the second compressor, and the first condenser passes through the second compressor. The third regenerator is supercooled and enters the second throttling member for adiabatic throttling, and the other path is sucked in by the third compressor, is supercooled by the second regenerator, and enters the third throttling member for adiabatic throttling.

Further optimization, the second compressor and the third compressor are connected in parallel with the top gas outlet of the gas-liquid separator and the intersection of the outlet of the first compressor.

Further optimization, the low-grade low-temperature heat source is one or more mixed forms of energy such as solar energy, waste heat generated by factories, and groundwater source heat energy.

Further optimization, the heat exchangers such as the first condenser, the second condenser, the evaporator, the first regenerator, the second regenerator, and the third regenerator are plate heat exchangers, casing heat exchangers Heater or Shell and Tube Heater.

Further optimization, the working medium of the low pressure stage compression subsystem, the first high pressure stage condensation temperature system and the second high pressure stage condensation temperature system are all R245fa, R1234yf, R1234ze, R152a, R236fa, R600a, R600, R227ea, R236ea or R245ca One or a mixture of both, the working medium of the low-grade low-temperature heat source is water or industrial waste heat.

The beneficial effects of the present invention are:

The invention uses the high and low pressure two-stage compression method to solve the problem that the single-stage compression ratio of the high-temperature heat pump is too large, which leads to the low heating efficiency. The heating heat pump cycle improves the heating performance of the heat pump system to save high-grade electric energy, and combined with the regenerative technology, the system makes full use of low-grade heat energy and reduces the energy consumption of the compressor. The invention provides a cascade heating large temperature span high temperature heat pump system, which achieves the purpose of improving the energy efficiency of the unit, saving energy and protecting the environment, and meeting the demand for high temperature hot water or steam in life or production.

Description of drawings

Fig. 1 is the structural representation of the present invention;

Reference numerals: 201, the first compressor, 202, the gas-liquid separator, 203, the second compressor, 204, the first condenser, 205, the third regenerator, 206, the second throttle member, 207, The third compressor, 208, the second condenser, 209, the second regenerator, 210, the third throttle element, 211, the first regenerator, 212, the first throttle element, 213, the evaporator.

Detailed ways

The present invention will be specifically described below in conjunction with the embodiments. It is necessary to point out that this embodiment is only used to further explain the present invention, and should not be construed as a limitation on the protection scope of the present invention. Those skilled in the art can make Some non-essential improvements and adjustments.

The specific embodiment of the present invention is:

A large temperature span high temperature heat pump system includes a low pressure stage compression subsystem, a first high pressure stage condensing temperature system and a second high pressure stage condensing temperature system, wherein the low pressure stage compression subsystem includes a first compressor 201, a gas Liquid separator 202, first throttling member 212, evaporator 213, first regenerator 211, third regenerator 205, second regenerator 209, the first high-pressure stage condensing temperature system includes serially connected The second compressor 203, the first condenser 204, the third regenerator 205 and the second throttling component 206, the second high-pressure stage condensing temperature system includes a third compressor 207, a second condenser 208, a second The regenerator 209 and the third throttling part 210, the second throttling part 206 and the third throttling part 210 are connected in parallel with the gas-liquid separator 202;

The superheated refrigerant vapor generated by the first compressor 201 and the saturated refrigerant vapor generated by the gas-liquid separator 202 are mixed and divided into two paths, one path is sucked into the second compressor 203, and the first condenser 204 first passes through the refrigerant. The third regenerator 205 is supercooled, and then enters the second throttling member 206 for adiabatic throttling; the other path is sucked into the third compressor 207, condensed and released through the second condenser 208, and passed through the second regenerator 209. The cold and third throttle member 210 throttles adiabatically.

The saturated refrigerant vapor generated after the external medium enters the evaporator 213 enters the first regenerator 211 for superheating and is divided into two paths, one of which flows into the second regenerator 209 for secondary superheating, and then It enters the gas-liquid separator 202 through the third throttling member 210 , and the other way flows into the third regenerator 205 for secondary superheating. After the secondary superheated refrigerant vapor is mixed, it is sucked into the first compressor 201 The refrigerant wet vapor in the gas-liquid separator 202 is divided into two parts, one part is generated as saturated refrigerant vapor mixed with the superheated refrigerant vapor generated by the first compressor 201 and flows out, and the other part generates saturated refrigerant liquid flow After entering the first regenerator 211, it is sub-cooled, and after being sub-cooled, it enters the first throttling member 212 for adiabatic throttling, and then flows into the evaporator 213, where heat exchange occurs with the low-grade and low-temperature heat source, and the wet vapor of the refrigerant evaporates. It absorbs heat and becomes saturated refrigerant vapor.

The high-temperature and high-pressure refrigerant vapor generated by the first compressor 201 and the saturated refrigerant vapor generated in the gas-liquid separator 202 are divided into two paths when they flow out, one of which enters the second compressor 203, and the superheated The refrigerant vapor is compressed to the first condensing pressure P _k1 , the superheated refrigerant vapor in the first condenser 204 exchanges heat with the external working medium at 20-30°C, and the superheated refrigerant vapor condenses and releases heat to become the first condensing pressure The saturated refrigerant liquid under P _k1 , the saturated refrigerant liquid first enters the third regenerator 205 and merges with the first regenerator 211 and then is divided into two paths, and the superheated refrigerant vapor entering the third regenerator 205 generates heat Exchange, after heat exchange, the saturated refrigerant liquid in the third regenerator 205 is supercooled, and then enters the second throttling component 206 for adiabatic throttling; the other way enters the third compressor 207, and the third compressor 207 The superheated refrigerant vapor is compressed to the second condensing pressure P _k2 , and the superheated refrigerant vapor in the second condenser 208 exchanges heat with the medium-temperature medium heated to 70-80° C. from the first condenser 204 . The superheated refrigerant vapor in 208 condenses and releases heat into saturated refrigerant liquid at the second condensing pressure P _k2 , and the saturated refrigerant liquid enters the second regenerator 209 and is divided into two parts after coming from the first regenerator 211. The refrigerant entering the second regenerator 209 all the way to heat exchange, and then the refrigerant entering the second regenerator 209 is subcooled, and the subcooled refrigerant enters the third throttling member 210 and is adiabatically throttled.

The specific working process is as follows: the refrigerant wet vapor absorbs the low-grade waste heat from the outside in the evaporator 213 and becomes a saturated refrigerant vapor, which enters the first regenerator 211 and the saturated refrigerant liquid flowing out from the gas-liquid separator 202. For heat exchange, the superheated refrigerant vapor is divided into two paths, one of which enters the second regenerator 209, exchanges heat with the saturated refrigerant liquid from the second condenser 208 and is overheated again, and the other enters the second regenerator 209. In the third regenerator 205, it exchanges heat with the saturated refrigerant liquid from the first condenser 204 and is superheated again. The two refrigerant vapors that have been superheated again are merged and then enter the first compressor 201 for adiabatic compression. After being compressed to the condensation pressure at the intermediate temperature, it is mixed with the saturated refrigerant gas from the gas-liquid separator 202 . The mixed superheated refrigerant vapor enters the second compressor 203 and is adiabatically compressed to the condensing pressure at the first condensing temperature, and then enters the first condenser 204 for heat exchange with the external low-temperature working medium, and the condensation heat release is: The saturated refrigerant liquid enters the third regenerator 205 again to exchange heat with the superheated refrigerant from the first regenerator 211 , and the refrigerant in the first condenser 204 is subcooled and then enters the second throttling member 206 Adiabatic throttling and depressurization to the condensing pressure at the intermediate temperature; the other route enters the third compressor 207 and is adiabatically compressed to the condensing pressure at the second condensing temperature, enters the second condenser 208, and is connected with the condensing pressure from the first condenser 204. The heated working medium undergoes heat exchange again, and the temperature of the working medium rises to a predetermined temperature again. The refrigerant in the second condenser 208 condenses and releases heat to become saturated refrigerant liquid, enters the second regenerator 209, exchanges heat with the refrigerant from the first regenerator 211, and is cooled by the pre-cooled subcooling The refrigerant liquid enters the third throttling part 210 and is adiabatically throttled to the condensation pressure at the intermediate temperature, and then mixed with the adiabatic throttling working medium of the second throttling part 206 and then enters the gas-liquid separator 202 together. The wet vapor of the refrigerant entering the gas-liquid separator 202 undergoes gas-liquid separation, and a part becomes saturated refrigerant and is sucked by the second compressor 203 and the third compressor 207; the other part becomes a saturated refrigerant liquid and flows to the first heat recovery. inside the device 211. The saturated refrigerant liquid flowing to the first regenerator 211 is adiabatically throttled to the evaporation pressure at the evaporation temperature by the first throttling member 212, and then enters the evaporator 213 again to evaporate and absorb heat with the external low-grade waste heat and waste heat. a cycle.

The foregoing has shown and described the main features of the present invention, methods of use, basic principles, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above-mentioned embodiments. The above-mentioned embodiments and the description in the specification are only the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will also be based on There are various changes and modifications in practice which fall within the scope of the claimed invention. The claimed scope of the present invention is defined by the appended claims and their equivalents.

Claims (6)

1. A large temperature and high temperature heat pump system, characterized in that it comprises a low pressure stage compression subsystem, a first high pressure stage condensing temperature system and a second high pressure stage condensing temperature system, wherein the low pressure stage compression subsystem comprises a serially connected a compressor (201), a gas-liquid separator (202), a first throttling component (212), an evaporator (213), a first regenerator (211), a third regenerator (205), a second A regenerator (209), the first high-pressure stage condensing temperature system includes a second compressor (203), a first condenser (204), a third regenerator (205) and a second throttling component sequentially connected in series (206), the second high-pressure stage condensing temperature system includes a third compressor (207), a second condenser (208), a second regenerator (209) and a third throttling component (210), the The second throttling component (206) and the third throttling component (210) are connected in parallel with the gas-liquid separator (202); The saturated refrigerant vapor generated after the external medium enters the evaporator (213) enters the first regenerator (211) to be superheated and is divided into two paths, one of which flows into the second regenerator (209) After secondary superheating, it enters the gas-liquid separator (202) through the third throttling component (210), and the other way flows into the third regenerator (205) for secondary superheating, and the secondary superheated refrigerant The vapor is mixed and sucked by the first compressor (201); the refrigerant wet vapor in the gas-liquid separator (202) is divided into two parts, and one part is generated as saturated refrigerant vapor and the first compressor (201) The generated superheated refrigerant vapor mixes and flows out, and another part of the saturated refrigerant liquid flows into the first regenerator (211) to be supercooled, and after being supercooled, enters the first throttling component (212) for adiabatic throttling , and then flows into the evaporator (213) to exchange heat with the low-grade and low-temperature heat source, and the wet refrigerant vapor evaporates and absorbs heat to become saturated refrigerant vapor. 2. The large temperature span high temperature heat pump system according to claim 1, characterized in that, the refrigerant wet vapor in the gas-liquid separator (202) and the superheated refrigerant generated by the first compressor (201) When the steam flows out, it is divided into two paths, one of which is inhaled by the second compressor (203), supercooled by the first condenser (204) through the third regenerator (205), and enters the second throttling component (206) Adiabatic throttling, the other path is sucked by the third compressor (207), supercooled by the second regenerator (208), and enters the third throttling component (210) for adiabatic throttling. 3. The large temperature span high temperature heat pump system according to claim 1, wherein the second compressor (203) and the third compressor (207) are connected in parallel with the gas-liquid separator (202) after being connected in parallel. The top gas outlet and the outlet of the first compressor (201) are connected at the intersection. 4 . The high temperature and high temperature heat pump system according to claim 1 , wherein the low-grade low-temperature heat source is one or more mixed forms of energy such as solar energy, waste heat generated by factories, and groundwater source heat energy. 5 . 5. The large temperature span high temperature heat pump system according to claim 1, wherein the first condenser (204), the second condenser (208), the evaporator (213), the first heat recovery The heat exchangers such as the regenerator (211), the second regenerator (209), and the third regenerator (205) are plate heat exchangers, casing heat exchangers or shell-and-tube heat exchangers. 6. A large temperature span high temperature heat pump system according to claim 1, wherein the working medium of the low pressure stage compression subsystem, the first high pressure stage condensing temperature system and the second high pressure stage condensing temperature system are One or a mixture of R245fa, R1234yf, R1234ze, R152a, R236fa, R600a, R600, R227ea, R236ea or R245ca, the working medium of the low-grade low-temperature heat source is water or industrial waste heat.

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