CN210663453U

CN210663453U - Dual-purpose switching type heat pump unit for preventing freezing pipe

Info

Publication number: CN210663453U
Application number: CN201921789162.2U
Authority: CN
Inventors: 刘小江
Original assignee: Individual
Current assignee: Individual
Priority date: 2019-10-23
Filing date: 2019-10-23
Publication date: 2020-06-02
Anticipated expiration: 2029-10-23

Abstract

The utility model provides a dual-purpose switching heat pump unit for preventing freezing pipes, which comprises a first heat exchanger, a second heat exchanger, a first throttling device, a first compressor and two first switching valves, wherein the first throttling device is connected with the first heat exchanger and the second heat exchanger, the first ends of the two first switching valves are both communicated with the first compressor, and the second ends and the third ends of the two first switching valves are respectively connected with the first heat exchanger and the second heat exchanger; the first switching valve is used for switching the working states of the first heat exchanger and the second heat exchanger to realize; the first heat exchanger absorbs heat of the interaction medium in the heat exchange tower, and the second heat exchanger releases the heat to the end of a user; alternatively, the first heat exchanger releases heat to the interaction medium in the heat exchange column and the second heat exchanger absorbs heat from the user end. The utility model provides a prevent to freeze dual-purpose switching formula heat pump set of pipe switches the replacement water route through the valve and switches to avoid the water route to switch the adverse effect that brings.

Description

Dual-purpose switching type heat pump unit for preventing freezing pipe

Technical Field

The utility model relates to a refrigeration heat pump air conditioner technical field especially relates to a prevent to freeze dual-purpose switching formula heat pump set of pipe.

Background

Along with the economic development, the consumption of fossil mineral energy by human beings is further increased, the corresponding emission of carbon dioxide is also increased, the greenhouse effect is increasingly shown, the current environment is increasingly worsened, the sea level is continuously increased, the fact that glaciers melt is not contended, the fact that the activity of human beings is intensified and mineral fossil energy is excessively consumed is related, the search for new alternative energy becomes increasingly important, the energy-saving and emission-reducing tasks are repeated at random, the continuous innovation and the adoption of new technologies to realize low-energy-consumption and high-efficiency heating meet a technical obstacle, particularly, most of centralized heating still adopts the traditional boiler heating mode to meet the requirements of people, which violates the current energy-saving and emission-reducing trend, a series of relevant policies are made by parties and governments, the coal power is vigorously promoted to be changed to reduce the emission of greenhouse gas, the aim of alleviating the gradual environmental deterioration is achieved, and the heat source tower related technologies appear more than, many related technologists overcome the difficulty for solving the problems, but still have difficulty in realizing large-scale commercial operation even solving the related problems, and the problems of corrosion resistance are not completely solved, the problems of solution loss and frozen pipes caused by the fact that the freezing point temperature of the solution moves upwards are not solved ideally to different degrees, so that the commercial operation cost and the investment cost restrict the rapid popularization of the related technology of the current heat source tower.

In order to solve the problem, the utility model discloses several aspects combination formula innovations have been made at central air conditioning system to reach and satisfy central air conditioning unit summer both can refrigerate, winter also can last high-efficient stable heating, it is much higher to compare current air-cooled heat pump set energy efficiency ratio, the highest energy efficiency ratio of general air-cooled heat pump set is at 2.8 times, and adopt its energy efficiency ratio of liquid heat source tower unit of preventing frostbite and can reach 5.8 times the most, this is that air-cooled heat pump set is high one time, moreover air-cooled heat pump exists the defrosting problem. The existing water source heat pump can be realized only by geographical conditions, the water source heat pump has relatively high cost, and the scale is very painful. The heat source tower has no defrosting trouble, and particularly, the technology can thoroughly solve the great problem that the user experience is influenced by defrosting. The air contains abundant latent heat of water vapor and sensible heat of the air, and how to convert the latent heat of the water vapor in the air into heat energy which can be utilized by people to benefit human beings is a difficult task in front of science and technology workers. The fossil energy is used for heating and belongs to energy conversion (chemical energy is converted into heat energy), the energy conversion cannot be realized by 100%, energy is lost in the conversion process, but a heat pump is different, the heat pump belongs to energy transfer, the energy transfer can reach the efficiency of more than 500%, the refrigerant is subjected to phase change through a compressor, and the low-temperature heat is transferred to the higher temperature through heat exchange, so that the energy conversion and the energy transfer have quite different effects.

The air energy heat pump in cold winter is afraid of too large water vapor content in air, and when the relative humidity in air is high, the normal operation of a heat pump unit is obstructed, the evaporator is frosted frequently, so that an air duct is blocked, a heat source is reduced greatly, the air conditioning effect is reduced greatly, much electric energy is consumed to defrost, much time is spent to defrost, heating operation is stopped during defrosting, heat is required to be taken from a room to defrost, and a user is uncomfortable. Therefore the utility model discloses just for become the harmful to the benefit, adopt the antifreeze to come direct and air to carry out heat exchange, still absorb the latent heat of a large amount of in the air steam when absorbing air sensible heat process, lead to in the air moisture enter into the antifreeze to constantly dilute the concentration of antifreeze, will freeze when the antifreeze is diluted to freezing point temperature, and then can expand the copper pipe of evaporimeter bad, consequently the utility model discloses a for the system has configured the relevant enrichment facility of rare antifreeze to produced steam passes through heat energy feedback system again and absorbs the heat that is used for increasing the heating in the system to the latent heat of steam in the system, outside arranging the system to the comdenstion water again, realizes the concentration of negative pressure evaporation heat energy feedback. More importantly the utility model discloses a calcium chloride antifreeze is as exchanging thermal medium with the air, and calcium chloride solution has very strong corrosive action to the metal, if calcium chloride adds the corrosion inhibitor, then the calcium chloride that adds the corrosion inhibitor is very weak (belong to normal life scope) to the metal corrosivity below 25 ℃, and can not the scale deposit yet, have very strong economic use value, not only the running cost is low and investment cost is also cheap, and it is wide to be suitable for the low temperature range, there is not too big influence to the environment, if dispose antifreeze enrichment facility, then it has just not a bit influence to the environment.

It is known that a four-way valve is commonly adopted by a household air conditioner to switch heating and cooling functions, and defrosting depends on the four-way valve to realize reverse operation defrosting; the large and medium central air conditioner can not adopt the four-way valve to switch the functions of the central air conditioner, because the larger four-way valve is difficult to ensure the processing precision requirement to prevent the series leakage between high pressure and low pressure, if the series leakage of refrigerant between high pressure and low pressure is caused, the effect is influenced and the energy is wasted, and the installation of the larger four-way valve is also a great problem, welding is necessary to achieve the higher air tightness requirement, the volume of components in the welding process is too large, the heat dissipation is fast, the oxygen welding temperature requirement can not be met, if a method of increasing heat is adopted, the four-way valve is easy to deform in the heating process, so that the normal operation of a heat pump set can not be realized, the large screw unit can not adopt the four-way valve to realize the switching of the refrigeration and heating functions, but adopts the switching of a water path, which has a completely different effect with the, the latter worrys about the concentration of the antifreeze solution diffusing into the condenser with higher temperature, because the valve adopted for water path switching is difficult to completely close completely at one percent without leakage at all, the heat pump unit operates in winter, even one thousandth of the concentration of the antifreeze solution can cause huge corrosion to the condenser, and as the corrosivity of the calcium chloride antifreeze solution appears under the condition of higher temperature and the scaling problem is serious, the calcium chloride is used as the antifreeze solution, and the service life of the heat source tower heat pump unit adopting the water path switching is about two years, so that the calcium chloride is used as the antifreeze solution and the water path switching mode is inevitably failed to end up, and therefore, people in the industry consistently deny that the calcium chloride can be used as the antifreeze solution of the heat source tower, which is a matter impossible, which is a conclusion that scientific basis is lacked. The utility model discloses a just broken the function switching that the conventional adoption gas tightness is very strong and be fit for large-scale central air conditioning unit refrigeration and heat, changed traditional water route switching thinking, solved simultaneously can't and calcium chloride of big cross valve be heat source tower antifreeze fluid can.

The most critical factor for the success is the selection of the function switching technology, because it is difficult to completely close a large valve, especially when the fluid contains metal rust, the situation is always inexhaustible, and the phenomenon of fluid leakage occurs, the calcium chloride solution can diffuse from high concentration to low concentration solution through a tiny gap where the valve is not completely closed, and then the calcium chloride solution enters a condenser with higher temperature, the corrosion action of the calcium chloride solution on the metal is accelerated when the temperature of the calcium chloride solution exceeds 40 ℃, the temperature of the condenser generally exceeds 40 ℃, copper pipes and steel plates are easily corroded by the calcium chloride solution when the temperature of the condenser is higher, while the metal in the case of a low-temperature evaporator is completely different and is a corrosion rate which is hundreds times higher than that of the evaporator, which is very plausible, and vicious circle is generated inevitably, so that the valve is difficult to close, and the valve core leaks water and splashes to the surface of other equipment, so that the motor and the pipeline related to the machine room are corroded.

The water-free cooling and heating integrated central air conditioner with the help of the boiler for heating can realize heating in winter and cooling in summer by using a module unit taking water as a cooling and heating carrier at present, but defrosting is still performed according to a traditional reverse operation mode, so that the user experience can be seriously influenced, and energy is wasted due to the fact that high-low pressure leakage of a four-way valve is caused by frequent switching of reverse operation of the four-way valve. The multi-connected air-cooling unit is not related to a water-cooling and heating dual-purpose air-conditioning unit, the refrigerating and heating energy efficiency ratio of the multi-connected air-cooling unit is very low, the most important point is that the multi-connected air-cooling unit also uses a compressor as a conveying pump for conveying cold or heat, the compressor cannot be used as the cold or heat conveying pump, the cold and heat transfer can be realized by using the compressor to carry out refrigerant phase change, so that the multi-connected air-cooling unit is economical and labor-saving, the gas-phase fluid has the density far lower than that of the liquid fluid, the carried cold and heat are relatively limited, but the pressure of the gas-phase fluid is not inferior to the resistance brought by the pressure of the liquid fluid, the energy consumption is larger by overcoming the resistance of a pipeline and the pressure difference to convey a gas-phase refrigerant. Therefore, the purpose of heat transfer is achieved by adopting a compressor to form pressure difference on a refrigerant at a short distance and realizing phase change through heat dissipation, then cold or heat is exchanged to liquid water in a heat exchange mode, and the liquid water carrying the cold or heat is remotely conveyed to the tail end of a user by a pump, so that the most economic technical scheme is achieved, and the central air conditioner saves energy compared with a household air conditioner. According to the principle, the technical scheme is that water is used as the heat-carrying and cold-carrying fluid to realize the utilization of clean air conditioning and high-efficiency air energy.

The user has been confused for a long time to the traditional mode of defrosting, must adopt the comfort level requirement that traditional boiler heating could satisfy the user only, still need to get heat from the room when the air-cooled heat pump defrosts and be used for defrosting, and it is longer to change the frost time, the power consumption is also many, especially under the lower great condition of humidity of ambient temperature, it is more to change the frost time, the corresponding reduction of heating time is many, form vicious circle like this, it stops heating to change the frost, still need to ask for heat from the room to change the frost, so the user can't endure this kind of jiong condition, only need to adopt the boiler heating mode to satisfy oneself comfort level requirement with sacrificing the environment as the cost. The northern air energy heat pump unit in high latitude has extremely poor operation condition, even if the northern air energy heat pump unit can be operated, the northern air energy heat pump unit is very low in energy efficiency ratio, and is not as economical and economical as boiler heating. Therefore, some scientific and technological workers adopt a gas-supplementing enthalpy-increasing technical method to solve the problem of poor operation condition of a heat pump in a low-temperature environment, also adopt a multi-stage compression mode to solve the problem, and also adopt a cascade heat pump unit to solve the heating problem under the condition of extremely low temperature, which can increase a lot of cost of equipment investment, and in order to meet the requirement of heating in winter, the surplus of equipment capacity during cooling in summer is inevitably overlarge. These problems need to be solved, the utility model discloses a new method is but has adopted very low-priced technical scheme, can solve this type of problem well, this is the same with tonifying qi enthalpy increase technical principle, the compression ratio that is close to the compressor limit is very low to its energy efficiency ratio, can adopt the method that reduces condenser pressure or improve evaporator pressure to reach the purpose that reduces the compression ratio, finally reach heat pump set can normal operating under low temperature environment, and the energy efficiency ratio can reach more ideal state, we know that when the compression ratio is higher, the gas delivery volume will reduce, and compressor outlet temperature can be very high, this is because the gas delivery pressure forms high temperature gaseous phase insufficient and is detained in the exit of compressor, and high temperature gas backward flow is in a new dynamic balance state with advancing, its backward flow trend just increases when the compression ratio increases, there is not more refrigerant fluid that moves ahead can take away the heat the reason, in the past, the motor of the compressor is burnt, the refrigerant oil is gasified, and the sealing of the compressor is more difficult, so that the vicious circle is increased continuously. Along with the principle, people can find that the current air supply enthalpy increase mode does not adopt a high-low pressure short circuit mode to increase the air output of the compressor and increase the enthalpy value of the compressor, take away the heat at the outlet of the retained compressor, increase the pressure of the evaporator to reduce the compression ratio, thereby restraining the occurrence of vicious cycle of the heat pump unit and returning the heat pump unit to a normal operation state. In fact, the complex air-supplying enthalpy-increasing technology is not needed to be adopted along the reason, the technical scheme is simple, feasible and reliable, the effect is better, and the user does not need to spend more money and invest in redundant equipment capacity. The liquid fluid displacement device is added in front of the evaporator, an electric heating rod is arranged in the device, the device is simple and practical, the device can be used for maintaining the normal operation of the heat pump in a low-temperature environment and improving the energy efficiency ratio, the installation of the electric heating rod can improve the enthalpy value of the refrigerant of the evaporator, so that the compression ratio of the heat pump unit is reduced, and finally the energy efficiency ratio is improved. The power of the electric heating rod can be adjusted steplessly, heat capacity increase in extremely low temperature periods in winter is achieved, and initial investment cost of users is reduced.

The larger the compression ratio, the lower the energy efficiency ratio, because the compressor needs to overcome the pressure of a larger refrigerant to complete the compression work, the compressor has a limit pressure difference, the limit compression ratio is different for different compressor types, generally difficult to exceed 10 times, the piston compressor as a volume compression type is 8 times compression ratio at the maximum when compressing ammonia gas, 10 times compression ratio at the maximum when compressing Freon, and is difficult to exceed 4 times for a turbine centrifugal compressor, and the power consumption of the compressor is larger as the compressor approaches the limit compression ratio, the limit compression ratio is the asymptote of the power consumption curve of the compressor, the power consumption is larger as the compressor approaches the asymptote, and the power consumption is smaller as the compressor approaches the asymptote. Therefore, the multi-stage compression and cascade heat pump unit achieves the purposes of energy conservation and stable work of the extremely low temperature heat source heat pump according to the principle. Therefore the utility model discloses an adopted evaporative condenser to realize that the stable high-efficient operation of low temperature heat source heat pump is the most critical part as heat transfer device in the middle of two compressors, this heat exchanger part both can regard as the endless condenser of one-level heat pump, can regard as the endless evaporimeter of second grade heat pump simultaneously again.

In view of above-mentioned technical background and the desideratum to environmental protection to based on the not enough of the all kinds of heat pumps of reality, the utility model discloses a to six technical key points innovation and combination formula innovation: firstly, waterway switching is changed into a refrigerant switching mode, and switching is realized in a three-way valve mode with high air tightness and reliability, so that leakage between high pressure and low pressure of a refrigerant can be completely avoided; secondly, a reliable technology is adopted to prevent the possibility that the evaporator of the heat pump unit is frozen, and three available technical schemes are adopted, wherein one is a pycnometer photosensitive antifreeze near-freezing temperature control principle, the second is a pycnometer contact type antifreeze near-freezing temperature control principle, and the third is to control alarm and emergency shutdown when the temperature is near the freezing temperature according to the change of the light refraction angle caused by the concentration change of the antifreeze; thirdly, based on the improvement of the two technical key points, calcium chloride antifreeze is adopted as a medium for heat exchange between a heat source tower and air; fourthly, in order to prevent the loss of the antifreeze solution from causing the pollution to the environment and avoiding the need of increasing the operation cost, the heat source tower is provided with a negative pressure low temperature heat pump type solution concentration device, and the utility model patent number of the concentration device are respectively: 201910781092.4, respectively; 201921374643.7, respectively; five, adopted and can prevent that the rainwater from wafting into "dual-purpose tower" of system, can also prevent simultaneously that elegant of solution is to the pollution of all ring edge borders, this "dual-purpose tower" utility model patent and utility model patent number do respectively: 201910453244.8, 201920783489.2; six, in order to be more to be fit for high latitude low temperature environment down the high-efficient steady operation of heat pump, the utility model discloses an adopted two kinds of schemes, one kind is that increase enthalpy drop compression ratio technique, just connect a liquid refrigerant volume before going into the evaporimeter, be provided with electric heater unit in this volume, this is only fit for single compressor structural style, can adopt medium temperature refrigerant cycle system and low temperature refrigerant cycle system serial-type circulation structural style to two compressor structural styles, only dispose an intermediate heat exchanger between two circulation systems, this intermediate heat exchanger is evaporative condenser, evaporative condenser can regard as the evaporimeter of medium temperature circulation system, can regard as low temperature circulation system's condenser simultaneously again. The six points have innovation on a single point and also have innovation contents combined with each other.

SUMMERY OF THE UTILITY MODEL

The utility model provides a technical problem provide a prevent to freeze dual-purpose switching formula heat pump set of pipe to solve the technical problem that heat pump set relies on the water route to switch among the prior art.

In order to solve the technical problem, the utility model provides a dual-purpose switching heat pump unit of pipe prevents freezing, including first heat exchanger, second heat exchanger, first throttling arrangement, first compressor and two first switching valves, first throttling arrangement connects first heat exchanger with the second heat exchanger, two first switching valve's first end all with the first compressor intercommunication, two first switching valve's second end and third end respectively with the first heat exchanger with the second heat exchanger is connected; the first switching valve is used for switching the working states of the first heat exchanger and the second heat exchanger to realize;

the first heat exchanger absorbs heat of an interaction medium in the heat exchange tower, and the second heat exchanger releases the heat to a user terminal;

alternatively, the first heat exchanger releases heat to the interaction media in the heat exchange column and the second heat exchanger absorbs heat from the user terminal.

Preferably, the heat pump unit further comprises an enthalpy increasing and compression reducing ratio device, and the first throttling device is connected with the second heat exchanger through the enthalpy increasing and compression reducing ratio device.

Preferably, the heat pump unit further comprises a second throttling device, a second compressor and two second switching valves, wherein the second throttling device is connected with the first heat exchanger and the second heat exchanger;

first ends of the two second switching valves are communicated with the second compressor, and second ends and third ends of the two second switching valves are respectively connected with the first heat exchanger and the second heat exchanger;

the first heat exchanger, the second heat exchanger, the first throttling device, the first compressor and the first switching valve form a refrigerant circulating system; the first heat exchanger, the second throttling device, the second compressor and the second switching valve form another refrigerant circulation system.

Preferably, the heat pump unit further comprises a third heat exchanger, a third throttling device, a third compressor and two third switching valves, wherein the third throttling device is connected with the second heat exchanger and the third heat exchanger;

first ends of the two third switching valves are communicated with the third compressor, and second ends and third ends of the two third switching valves are respectively connected with the second heat exchanger and the third heat exchanger;

the first heat exchanger, the second heat exchanger, the first throttling device, the first compressor and the first switching valve form a refrigerant circulating system; the second heat exchanger, the third throttling device, the third compressor and the third switching valve form another refrigerant circulation system.

Preferably, the heat pump unit further comprises an antifreeze alarm and control device, and when the concentration of the antifreeze drops to a preset concentration value, the antifreeze alarm and control device alarms or stops the operation of the heat pump unit.

Preferably, the first switching valve comprises a valve body shell, a first pipeline, a second pipeline, a third pipeline, a first sliding rod, a sliding valve core, two auxiliary shafts, a convex sealing element, a circular sealing gasket and a control coil;

the first pipeline, the second pipeline and the third pipeline are respectively positioned at a first end, a second end and a third end of the valve body outer shell; the two auxiliary shafts are respectively arranged in the second pipeline and the third pipeline, one convex sealing element is arranged on one auxiliary shaft, the circular sealing gasket is arranged around the convex sealing element, the first sliding rod is suspended in the valve body shell, two ends of the first sliding rod are respectively connected with the two convex sealing elements, and the sliding valve core is in sliding connection with the first sliding rod;

the sliding valve core is a metal valve core, and the control coil is used for controlling the sliding valve core to move along the extension direction of the first sliding rod so as to seal the second pipeline or the third pipeline.

Preferably, the first switching valve comprises a valve body shell, a first pipeline, a second pipeline, a third pipeline, a control coil, two sealing rings, a sealing ring auxiliary shaft, a spring auxiliary shaft, a compression valve core, a compression spring, a second sliding rod and a flange;

the first pipeline, the second pipeline and the third pipeline are respectively positioned at a first end, a second end and a third end of the valve body outer shell;

the two sealing rings are arranged at two ends of the valve body shell, the two sealing rings are respectively adjacent to the second pipeline and the third pipeline, and a passage port is formed in each sealing ring; the sealing ring auxiliary shaft is positioned in the valve body shell and connected with the sealing ring, and the flange is arranged on the sealing ring auxiliary shaft; the two spring auxiliary shafts are respectively arranged in the second pipeline and the third pipeline, the compression spring is elastically connected with the compression valve core and the spring auxiliary shaft, and the second sliding rod penetrates through the flange and the sealing ring auxiliary shaft and then is connected with the compression valve core;

the compression valve core is a metal valve core, and the control coil is used for controlling one compression valve core to move along the extension direction of the second sliding rod so as to seal a passage port of the sealing ring.

Preferably, the antifreeze alarming and controlling device is a photoelectric monitor, a specific gravity monitor or a monitor combining photoelectricity and specific gravity.

In the dual-purpose switching heat pump unit for preventing freezing pipes, the first switching valve is used for switching the working states of the first heat exchanger and the second heat exchanger so as to realize that the first heat exchanger absorbs the heat of an interactive medium in a heat exchange tower, and the second heat exchanger releases the heat to the end of a user; or the first heat exchanger releases heat to the interaction medium in the heat exchange tower, and the second heat exchanger absorbs heat from the user terminal; therefore, the function of waterway switching in the prior art is replaced by the switching function of the first switching valve; the calcium chloride solution can be prevented from diffusing to the side of the fluid with higher temperature due to the switching of the water path, and the equipment can be prevented from being corroded.

Drawings

FIG. 1 is a schematic design diagram of a first embodiment of a dual-purpose switching heat pump unit for preventing freezing pipes according to the present invention;

FIG. 2 is a schematic diagram of a second embodiment of the dual-purpose switching heat pump unit for preventing freezing of tubes according to the present invention;

FIG. 3 is a schematic diagram of a design of a dual-purpose switching heat pump unit for preventing freezing pipes according to a third embodiment of the present invention;

FIG. 4 is a schematic diagram of a design of a fourth embodiment of the dual-purpose switching heat pump unit for preventing freezing;

FIG. 5 is a schematic diagram of a first switching valve of the dual-purpose switching heat pump unit for preventing freezing;

FIG. 6 is a schematic diagram of another preferred embodiment of a first switching valve of the dual-purpose switching heat pump unit for preventing freezing;

FIG. 7 is a schematic diagram of an antifreeze solution alarm and control device of the dual-purpose switching heat pump unit for preventing freezing;

FIG. 8 is a structural diagram of another preferred embodiment of an antifreeze alarming and controlling device of a dual-purpose switching heat pump unit for preventing freezing pipes according to the present invention;

FIG. 9 is a block diagram of still another preferred embodiment of the antifreeze solution alarming and controlling apparatus of the dual-purpose switching heat pump unit for preventing freezing of the tube.

The reference numbers illustrate:

1-a heat exchange tower, 4-a user terminal, 9-a first circulating pump and 10-a second circulating pump;

6-a first heat exchanger, 3-a second heat exchanger and 5-1 a first throttling device;

2-1-a first compressor, 7-1 a first switching valve;

2-2-second compressor, 7-2-second switching valve; 5-2 a second throttling device;

2-3-a third compressor, 7-3-a third switching valve; 6-1-a third heat exchanger; 5-3-a third throttling device;

8-1-enthalpy increasing and compression ratio reducing device and 8-antifreeze liquid alarming and controlling device;

23-valve body shell, 22-first pipeline, 14-second pipeline, 21-third pipeline, 15-auxiliary shaft, 16-convex sealing element, 17-control coil, 18-first slide bar, 19-slide valve core and 20-circular sealing pad;

32-sealing ring, 27-sealing ring auxiliary shaft, 35-spring auxiliary shaft, 26-compression valve core, 33-compression spring, 29-second sliding rod and 31-flange;

37-a liquid level box, 38-a liquid inlet pipe, 41-an overflow pipe, 36-a light beam device, 42-a first photosensitive element, 39-a specific gravity meter, 40-an antifreeze and 43-a black body;

45-first contact potential, 44-second contact potential, 43-conductive film;

46-light beam generating device, 48-light transmitting tube, 50-second photosensitive element and 47-light beam.

The objects, features and advantages of the present invention will be further described with reference to the accompanying drawings.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.

It should be noted that all the directional indicators (such as upper, lower, left, right, front and rear … …) in the embodiment of the present invention are only used to explain the relative position relationship between the components, the motion situation, etc. in a specific posture (as shown in the drawings), and if the specific posture is changed, the directional indicator is changed accordingly.

The utility model provides a prevent to freeze dual-purpose switching formula heat pump set of pipe.

First embodiment

Referring to fig. 1, the dual-purpose switching heat pump unit for preventing freezing pipes includes a first heat exchanger 6, a second heat exchanger 3, a first throttling device 5-1, a first compressor 2-1 and two first switching valves 7-1, wherein the first throttling device 5-1 is connected with the first heat exchanger 6 and the second heat exchanger 3, first ends of the two first switching valves 7-1 are both communicated with the first compressor 2-1, and second ends and third ends of the two first switching valves 7-1 are respectively connected with the first heat exchanger 6 and the second heat exchanger 3; the first switching valve 7-1 is used for switching the working states of the first heat exchanger 6 and the second heat exchanger 3 to realize;

the first heat exchanger 6 absorbs heat of the interaction medium in the heat exchange tower 1, and the second heat exchanger 3 releases heat to the user terminal 4;

alternatively, the first heat exchanger 6 gives off heat to the interaction medium in the heat exchange column 1 and the second heat exchanger 3 absorbs heat from the user terminal 4.

In winter, the heat exchange tower 1 may be a heat source tower, the exchange medium may be calcium chloride antifreeze, and the exchange medium may also be other types of antifreeze;

the first switching valve 7-1 is used for switching the working states of the first heat exchanger 6 and the second heat exchanger 3, so that the first heat exchanger 6 is an evaporator and the second heat exchanger 3 is a condenser;

the working principle of the heat pump unit is as follows:

the refrigerant is compressed into the condenser by the operation of the first compressor 2-1, and the refrigerant releases latent heat to warm medium water circulating at the other side of the condenser through phase change to increase the temperature of the refrigerant;

the raised heating medium water is brought to the user tail end 4 by the second circulating pump 10 to realize heating;

after releasing latent heat, the refrigerant is condensed into liquid refrigerant, and then the liquid refrigerant flows into the evaporator through the first throttling device 5-1 to absorb the latent heat of the anti-freezing solution on the other side of the evaporator to be evaporated; and is pressed into the condenser by the first compressor 2-1 again to realize the phase-change circulation process of the refrigerant;

after the temperature of the antifreeze releasing latent heat is reduced by about 5 ℃, the antifreeze is injected into the heat source tower by the first circulating pump 9 for spraying and exchanging heat with air;

the sensible heat of the air and the latent heat of the water vapor in the air are absorbed through spraying, the temperature of the air is increased, then the air is pumped into the evaporator by the first circulating pump 9, the latent heat is released to the refrigerant on the other side of the evaporator, and the circulation process of the anti-freezing solution is achieved.

In summer, the heat exchange tower 1 can be a cooling tower, and the exchange medium can be cooling water; the first switching valve 7-1 is used for switching the working states of the first heat exchanger 6 and the second heat exchanger 3, so that the second heat exchanger 3 is an evaporator, and the first heat exchanger 6 is a condenser;

the working principle is similar to that in winter, and the difference is that the warm medium water driven by the second circulating pump 10 takes away cold rather than heat.

The heat pump unit also comprises an antifreeze alarming and controlling device 8, and when the concentration of the antifreeze is reduced to a preset concentration value, the antifreeze alarming and controlling device 8 alarms or stops the heat pump unit.

Second embodiment

Please refer to fig. 2, based on the dual-purpose switching heat pump unit of the first embodiment of the present invention, the second embodiment of the present invention provides another dual-purpose switching heat pump unit of the anti-freezing pipe, which is different in that:

the heat pump unit also comprises an enthalpy increasing and compression reducing device 8-1, and the first throttling device 5-1 is connected with the second heat exchanger 3 through the enthalpy increasing and compression reducing device 8-1.

The enthalpy-increasing compression-reducing ratio device 8-1 comprises a liquid refrigerant volume, an electric auxiliary heating device and two electronic valves; one of said electrovalves connecting said first throttling means 5-1 with said second heat exchanger 3, one end of said volume of liquid refrigerant being connected with said second heat exchanger 3, the other end of said volume of liquid refrigerant being connected with the first throttling means 5-1 through the other electrovalve; and an electric auxiliary heating device is arranged in the volume of the liquid refrigerant and is used for realizing heating in a low-temperature environment.

In winter or in a low-temperature environment, the heat exchange tower 1 may be a heat source tower, the exchange medium may be calcium chloride antifreeze, and the exchange medium may also be other types of antifreeze;

increasing a volume of liquid refrigerant before the liquid refrigerant enters the evaporator; a set of electric heating device is arranged in the volume, and the electric heating device is started to play a role in increasing enthalpy and reducing compression ratio, so that the heat pump unit can normally and stably run in a low-temperature environment;

the electronic valve connected with the first throttling device 5-1 in series is closed, meanwhile, the other electronic valve is opened, so that liquid refrigerant can enter the volume of the liquid refrigerant, the temperature of the liquid refrigerant is raised through the electric heating device, the pressure of the refrigerant entering the evaporator is correspondingly raised, the gas transmission quantity is raised finally, the compression ratio is reduced, and the electric auxiliary heating enthalpy increasing technical mode is also suitable for the structural form of the double-screw compressor.

Third embodiment

Referring to fig. 3, based on the dual-purpose switching heat pump unit for preventing freezing pipes provided by the first embodiment of the present invention, the third embodiment of the present invention provides another dual-purpose switching heat pump unit for preventing freezing pipes, which is different from the first embodiment in that:

the heat pump unit also comprises a second throttling device 5-2, a second compressor 2-1 and two second switching valves 7-2, wherein the second throttling device 5-2 is connected with the first heat exchanger 6 and the second heat exchanger 3;

first ends of the two second switching valves 7-2 are both communicated with the second compressor 2-1, and second ends and third ends of the two second switching valves 7-2 are respectively connected with the first heat exchanger 6 and the second heat exchanger 3;

the first heat exchanger 6, the second heat exchanger 3, the first throttling device 5-1, the first compressor 2-1 and the first switching valve 7-1 form a refrigerant circulating system; the first heat exchanger 6, the second heat exchanger 3, the second throttling device 5-2, the second compressor 2-1, and the second switching valve 7-2 form another refrigerant circulation system.

In this embodiment, one of the first compressor 2-1 and the second compressor 2-1 is a fixed frequency compressor, and the other is an inverter compressor. The second switching valve 7-2 has the same function as the first switching valve 7-1.

In winter, the heat exchange tower 1 can be a heat source tower, and the exchange medium can be calcium chloride antifreeze solution; the first switching valve 7-1 and the second switching valve 7-2 are used for switching the working states of the first heat exchanger 6 and the second heat exchanger 3, so that the first heat exchanger 6 is an evaporator shared by the first compressor 2-1 and the second compressor 2-1, and the second heat exchanger 3 is a condenser shared by the first compressor 2-1 and the second compressor 2-1;

the working principle is as follows:

the sensible heat of the air and the latent heat of the vapor in the air are sprayed and absorbed in the heat source tower through the antifreeze liquid, so that the temperature of the antifreeze liquid is raised by about 5 ℃, and then the antifreeze liquid is pumped into the shared evaporator by the first circulating pump 9 to release the latent heat to the refrigerant on the other side of the shared evaporator so as to evaporate the refrigerant;

refrigerant evaporated by the shared evaporator is pressed into the shared condenser by the first compressor 2-1 and the second compressor 2-1 to release latent heat to warm water on the other side of the shared condenser, and then is condensed into liquid refrigerant; then flows into the shared evaporator again through the first throttling device 5-1 and the second throttling device 5-2;

meanwhile, the gas refrigerant in the shared evaporator is pressed into the shared condenser by the first compressor 2-1 and the second compressor 2-1 to release latent heat to warm medium water on the other side of the shared condenser, and then is condensed into liquid refrigerant;

then the refrigerant flows into the shared evaporator again through the first throttling device 5-1 and the second throttling device 5-2 to complete the circulation of the refrigerant, and the heating medium water in the shared condenser obtains the latent heat of the refrigerant and then is pumped into the user terminal 4 by the second circulating pump 10 to achieve the purpose of heating.

In summer, the heat exchange tower 1 can be a cooling tower, and the exchange medium can be cooling water; the first switching valve 7-1 and the second switching valve 7-2 are used for switching the working states of the first heat exchanger 6 and the second heat exchanger 3, so that the first heat exchanger 6 is a condenser shared by the first compressor 2-1 and the second compressor 2-1, and the second heat exchanger 3 is an evaporator shared by the first compressor 2-1 and the second compressor 2-1;

the working principle is similar to that in winter, except that the second circulation pump 10 delivers warm mordant water to the user terminals 4 as cold rather than as heat.

Referring to fig. 3 again, the so-called shared condenser is different from the conventional condenser in structure and is divided into two sections, the front section is the first compressor 2-1 and the combination, the rear section is the second compressor 2-1 and the two sections share the heat exchange fluid (refrigerant) on the other side, with the difference between the front and the rear.

The shared evaporator is divided into two halves, one half is combined with the first compressor 2-1, the other half is combined with the second compressor 2-1, and refrigerants in the two halves can exchange heat with antifreeze on the other common side.

Fourth embodiment

Referring to fig. 4, a fourth embodiment of the present invention provides another dual-purpose switching heat pump unit for preventing freezing based on the dual-purpose switching heat pump unit for preventing freezing provided by the first embodiment of the present invention, which is different from the first embodiment of the present invention,

the heat pump unit also comprises a third heat exchanger 6-1, a third throttling device 5-3, a third compressor 2-3 and two third switching valves 7-3, wherein the third throttling device 5-3 is connected with the second heat exchanger 3 and the third heat exchanger 6-1;

first ends of the two third switching valves 7-3 are both communicated with the third compressor 2-3, and second ends and third ends of the two third switching valves 7-3 are respectively connected with the second heat exchanger 3 and the third heat exchanger 6-1;

the first heat exchanger 6, the second heat exchanger 3, the first throttling device 5-1, the first compressor 2-1 and the first switching valve 7-1 form a refrigerant circulating system (low temperature); the second heat exchanger 3, the third heat exchanger 6-1, the third throttling device 5-3, the third compressor 2-3, and the third switching valve 7-3 form another refrigerant circulation system (medium temperature).

In this embodiment, the second heat exchanger 3 is used as an intermediate heat exchanger of two compressors and can be used as an evaporator and a condenser at the same time; the method has the advantages that the compression ratio of each cycle is low, the energy efficiency ratio is correspondingly high, and the total energy efficiency ratio after superposition is higher than that of a single-cycle heat pump system or a parallel-type cycle heat pump system.

The first heat exchanger 6, the second heat exchanger 3, the first throttling device 5-1, the first compressor 2-1 and the first switching valve 7-1 form a refrigerant circulating system; namely, a low-temperature refrigerant cycle system is formed.

The second heat exchanger 3, the third heat exchanger 6-1, the third throttling device 5-3, the third compressor 2-3 and the third switching valve 7-3 form another refrigerant circulating system; namely, a medium temperature refrigerant cycle system is formed.

In winter, the heat exchange tower 1 can be a heat source tower, and the exchange medium can be calcium chloride antifreeze solution; the first switching valve 7-1 is used for switching the working states of the first heat exchanger 6 and the second heat exchanger 3, so that the first heat exchanger 6 is an evaporator, and a section of the second heat exchanger 3 close to the first heat exchanger 6 is a condenser;

the third switching valve 7-3 is used for switching the working states of the second heat exchanger 3 and the third heat exchanger 6-1, and a section of the second heat exchanger 3 close to the third heat exchanger 6-1 is an evaporator; so that the third heat exchanger 6-1 is a condenser;

the working principle is as follows:

when the first circulating pump 9 pumps the antifreeze into the heat source tower for spraying and fully performing heat exchange with air, sensible heat in the air is absorbed, and latent heat of water vapor in the air is also absorbed, so that the temperature of the antifreeze can be increased by 3-5 ℃ and then the antifreeze enters the first heat exchanger 6 (evaporator); to release latent heat to the low temperature refrigerant on the other side of the first heat exchanger 6 (evaporator),

the liquid low-temperature refrigerant at the side is evaporated, the evaporated low-temperature refrigerant is pressed into the second heat exchanger 3 by the first compressor 2-1 and condensed by the medium-temperature refrigerant at the other side, and latent heat is released to the medium-temperature refrigerant to be changed into the liquid low-temperature refrigerant;

and enters the first heat exchanger 6 (evaporator) again through the first throttling device 5-1 to obtain the heat of the anti-freezing solution for evaporation, so that the circulation process of the low-temperature refrigerant is realized.

The medium-temperature refrigerant acquires latent heat of the low-temperature refrigerant, and the evaporated medium-temperature refrigerant is pressed into a third heat exchanger 6-1 (a condenser) by a third compressor 2-3 to release the latent heat to the warming medium water on the other side of the condenser;

after obtaining heat, the heating medium water is pumped into each user terminal 4 by the second circulating pump 10 to realize heating and heat dissipation;

meanwhile, the medium-temperature refrigerant is condensed into liquid medium-temperature refrigerant after releasing latent heat, and then enters the second heat exchanger 3 through the third throttling device 5-3, so that the circulation process of the medium-temperature refrigerant is realized.

The low-temperature refrigerant is in a first-stage circulation, directly performs heat exchange with the antifreeze under the low-temperature environment, and the antifreeze performs heat exchange on air and then transfers heat into the second heat exchanger 3; further transferring heat from the low temperature to the user terminal 4 by means of pump heat;

this process must be accomplished through a medium temperature refrigerant cycle, so the low temperature heat is achieved by two warm-up transfer processes.

Of course, the medium temperature refrigerant in the two serial circulation processes also has to pass through the two third switching valves 7-3; and the low-temperature refrigerant cycle must pass through two first switching valves 7-1, and the four three-way valves form a key refrigerant switching part.

In summer; the heat exchange tower 1 can be a cooling tower, and the exchange medium can be cooling water; the first switching valve 7-1 is used for switching the working states of the first heat exchanger 6 and the second heat exchanger 3, so that the first heat exchanger 6 is a condenser, and one side of the second heat exchanger 3, which is close to the first heat exchanger 6, is an evaporator;

the third switching valve 7-3 is used for switching the working states of the second heat exchanger 3 and the third heat exchanger 6-1, and a condenser is arranged on one side of the second heat exchanger 3 close to the third heat exchanger 6-1; so that the third heat exchanger 6-1 is an evaporator.

The working principle is similar to that in winter, except that the warm medium water delivered by the second circulation pump 10 is cold rather than heat for the user terminal 4.

The dual-purpose switching heat pump unit for preventing the freezing pipe provided by the embodiment; the heat pump type air conditioner is suitable for the operation of a heat pump in a low-temperature environment, and particularly can reduce the power output through a compressor variable-frequency operation mode of secondary medium-temperature refrigerant circulation under the condition of large difference between summer capacity and winter heating heat.

The utility model also provides a first switching valve 7-1.

Referring to fig. 5, in an implementation of the first switching valve 7-1 according to the present invention, the first switching valve 7-1 includes a valve body housing 23, a first pipe 22, a second pipe 14, a third pipe 21, a first sliding rod 18, a sliding valve core 19, two auxiliary shafts 15, a convex sealing member 16, a circular sealing gasket 20, and a control coil 17;

the first pipeline 22, the second pipeline 14 and the third pipeline 21 are respectively positioned at the first end, the second end and the third end of the valve body shell 23; the two auxiliary shafts 15 are respectively arranged in the second pipeline 14 and the third pipeline 21, one convex sealing element 16 is mounted on one auxiliary shaft 15, the circular sealing gasket 20 is arranged around the convex sealing element 16, the first sliding rod 18 is suspended in the valve body shell 23, two ends of the first sliding rod 18 are respectively connected with the two convex sealing elements 16, and the sliding valve core 19 is in sliding connection with the first sliding rod 18;

the spool 19 is a metal spool, and the control coil 17 is used to control the spool 19 to move along the extending direction of the first slide bar 18 to close the second pipe 14 or the third pipe 21.

In this embodiment, the first slide bar 18 may penetrate the spool 19, and the bump seal 16 has a bump that can be sealed, because the first slide bar 18 penetrates the gap formed by the spool 19.

It will be appreciated that the first conduit 22 is in communication with the first compressor 2-1, and the second conduit 14 and the third conduit 21 are in communication with the first heat exchanger 6 and the second heat exchanger 3, respectively. The auxiliary shaft 15 and the convex sealing member 16 are both formed with flow passages, and the sliding valve core 19 closes the flow passages when closing the second pipe 14 or the third pipe 21.

Two control coils 17 can be arranged at two ends in the valve body shell 23, and the power-on condition of the control coils 17 is controlled to attract and drive the sliding valve core 19 to move.

Referring to fig. 6, in another embodiment of the first switching valve 7-1 according to the present invention, the first switching valve 7-1 includes a valve body housing 23, a first pipe 22, a second pipe 14, a third pipe 21, a control coil 17, two sealing rings 32, a sealing ring auxiliary shaft 27, a spring auxiliary shaft 35, a compression valve core 26, a compression spring 33, a second sliding rod 29, and a flange 31;

the first pipeline 22, the second pipeline 14 and the third pipeline 21 are respectively positioned at the first end, the second end and the third end of the valve body shell 23;

the two sealing rings 32 are arranged at two ends of the valve body shell 23, the two sealing rings 32 are respectively arranged adjacent to the second pipeline 14 and the third pipeline 21, and a passage opening is formed in each sealing ring 32; the sealing ring auxiliary shaft 27 is positioned in the valve body shell 23 and is connected with the sealing ring 32, and the flange 31 is arranged on the sealing ring auxiliary shaft 27; the two spring auxiliary shafts 35 are respectively installed in the second pipeline 14 and the third pipeline 21, the compression spring 33 elastically connects the compression valve core 26 and the spring auxiliary shaft 35, and the second sliding rod 29 penetrates through the flange 31 and the seal ring auxiliary shaft 27 and then is connected with the compression valve core 26;

the compression valve core 26 is a metal valve core, and the control coil 17 is used for controlling one compression valve core 26 to move along the extending direction of the second sliding rod 29 so as to close a passage port of the sealing ring 32.

It will be appreciated that the first conduit 22 is in communication with the first compressor 2-1, and the second conduit 14 and the third conduit 21 are in communication with the first heat exchanger 6 and the second heat exchanger 3, respectively. The seal ring auxiliary shaft 27 and the spring auxiliary shaft 35 are both formed with flow passages, and when the compression valve core 26 closes the passage opening of the seal ring 32, the corresponding flow passages are also closed.

Two control coils 17 may be respectively disposed outside the second pipe 14 and the third pipe 21 and around the compression spool 26; the two control coils 17 may also be respectively disposed in the second pipe 14 and the third pipe 21, and disposed around the compression valve core 26;

the compression valve core 26 is driven to move in an attraction manner by controlling the electrification condition of the control coil 17.

In the present invention, the second switching valve 7-2 is identical to the third switching valve 7-3 in structure.

The utility model provides an antifreeze is reported to police and controlling means 8. And when the concentration of the antifreeze is reduced to a preset concentration value, the antifreeze alarming and controlling device 8 is used for alarming or stopping the work of the heat pump unit.

The antifreeze alarming and controlling device 8 is a photoelectric monitor, a specific gravity monitor or a monitor combining photoelectricity and specific gravity.

Referring to fig. 7, when the antifreeze alarming and controlling device 8 is a photoelectric monitor.

The antifreeze alarming and controlling device 8 comprises a monitor, a light beam generating device 46, a light transmitting tube 48 and a second photosensitive element 50; the light beam generating device 46 and the second photosensitive element 50 are respectively arranged at two sides of the light-transmitting tube 48, and the antifreeze 40 passes through the light-transmitting tube 48;

when the concentration of the antifreeze liquid 40 is greater than a preset concentration value; the light beam 47 emitted from the light beam generator 46 passes through the light-transmitting tube 48 and the antifreeze 40 and is irradiated on the second photosensitive element 50.

When the concentration of the antifreeze solution 40 is reduced to a preset concentration value, the light beam 47 emitted by the light beam generator 46 is refracted after passing through the light-transmitting tube 48 and the antifreeze solution 40, and is no longer irradiated on the second photosensitive element 50; when the monitor detects the situation, the monitor gives an alarm or stops the work of the heat pump unit.

Referring to fig. 8, when the antifreeze alarming and controlling apparatus 8 is a specific gravity monitor.

The antifreeze alarming and controlling device 8 comprises a monitor, a liquid level box 37, a liquid inlet pipe 38, an overflow pipe 41, a hydrometer 39, a first contact potential 45, a second contact potential 44 and a conductive film 43, wherein the liquid inlet pipe 38 and the overflow pipe 41 are respectively arranged at the bottom end and the top end of the liquid level box 37; after the antifreeze 40 flows into the liquid level tank 37 from the liquid inlet pipe 38, it flows out of the liquid level tank 37 from the overflow pipe 41;

one end of the specific gravity gauge 39 is suspended in the liquid level box 37, and the other end of the specific gravity gauge 39 extends into the top end of the liquid level box 37; the conductive film 43 is disposed at the other end of the hydrometer 39, and the first contact potential 45 and the second contact potential 44 are respectively located at two sides of the top end of the liquid level box 37;

when the concentration of the antifreeze liquid 40 is greater than a preset concentration value; the conductive film 43 is suspended above the first contact potential 45 and the second contact potential 44.

When the concentration of the antifreeze 40 drops to a predetermined concentration value, the conductive film 43 sinks following the specific gravity gauge 39, so that the conductive film 43 communicates the first contact potential 45 with the second contact potential 44.

When the monitor detects the situation, the monitor gives an alarm or stops the work of the heat pump unit.

Referring to fig. 9, the antifreeze alarming and controlling apparatus 8 is a monitor combining photoelectric and specific gravity.

The anti-freezing liquid alarming and controlling device 8 comprises a liquid level box 37, a liquid inlet pipe 38, an overflow pipe 41, a light beam device 36, a first photosensitive element 42, a specific gravity meter 39 and a black body 43. The liquid inlet pipe 38 and the overflow pipe 41 are respectively arranged at the bottom end and the top end of the liquid level box 37; after the antifreeze 40 flows into the liquid level tank 37 from the liquid inlet pipe 38, it flows out of the liquid level tank 37 from the overflow pipe 41;

one end of the specific gravity gauge 39 is suspended in the liquid level box 37, and the other end of the specific gravity gauge 39 extends into the top end of the liquid level box 37; the black body 43 is arranged at the other end of the hydrometer 39, and the emission beam device 36 and the first photosensitive element 42 are respectively positioned at two sides of the top end of the liquid level box 37;

when the concentration of the antifreeze 40 is greater than a preset concentration value; the black body 43 is located above the emission beam device 36, and the beam 47 emitted by the emission beam device 36 irradiates the first photosensitive element 42.

When the concentration of the antifreeze solution 40 drops to a preset concentration value, the black body 43 sinks following the specific gravity meter 39, so that the light beam 47 emitted by the light beam device 36 is blocked; no longer irradiates the first photosensitive element 42;

The above is only the preferred embodiment of the present invention, not limiting the scope of the present invention, all of which are under the concept of the present invention, the equivalent structure transformation made by the contents of the specification and the drawings is utilized, or the direct/indirect application in other related technical fields is included in the patent protection scope of the present invention.

Claims

1. A dual-purpose switching heat pump unit for preventing freezing pipes is characterized by comprising a first heat exchanger, a second heat exchanger, a first throttling device, a first compressor and two first switching valves, wherein the first throttling device is connected with the first heat exchanger and the second heat exchanger, the first ends of the two first switching valves are communicated with the first compressor, and the second ends and the third ends of the two first switching valves are respectively connected with the first heat exchanger and the second heat exchanger; the first switching valve is used for switching the working states of the first heat exchanger and the second heat exchanger to realize;

2. A heat pump unit according to claim 1, wherein said heat pump unit further comprises an enthalpy increasing compression reducing ratio means, said first throttle means being connected to said second heat exchanger through said enthalpy increasing compression reducing ratio means.

3. The heat pump unit of claim 1, wherein the heat pump unit further comprises a second throttling device, a second compressor and two second switching valves, wherein the second throttling device connects the first heat exchanger and the second heat exchanger;

4. The heat pump unit of claim 1, further comprising a third heat exchanger, a third throttling device, a third compressor and two third switching valves, wherein the third throttling device connects the second heat exchanger and the third heat exchanger;

5. The heat pump unit of any one of claims 1-4, further comprising an antifreeze alarm and control device for alarming or stopping the operation of the heat pump unit when the antifreeze concentration drops to a predetermined concentration value.

6. The heat pump unit according to any one of claims 1-4, wherein the first switching valve comprises a valve body shell, a first pipeline, a second pipeline, a third pipeline, a first sliding rod, a sliding valve core, two auxiliary shafts, a raised sealing element, a circular sealing gasket and a control coil;

7. The heat pump unit according to any one of claims 1-4, wherein the first switching valve comprises a valve body shell, a first pipeline, a second pipeline, a third pipeline, a control coil, two sealing rings, a sealing ring auxiliary shaft, a spring auxiliary shaft, a compression valve core, a compression spring, a second sliding rod and a flange;

the first pipeline, the second pipeline and the third pipeline are respectively positioned at a first end, a second end and a third end of the valve body shell;

8. A heat pump unit according to claim 5, characterised in that the antifreeze solution alarming and controlling means is a photoelectric monitor, a specific gravity monitor or a monitor combining photoelectric and specific gravity.