Fuel gas auxiliary heating type flue gas heat exchange frost suppression type heat pump air conditioning system

Abstract

The embodiment of the invention provides a fuel gas auxiliary heating type flue gas heat exchange frost restraining type heat pump air conditioning system. The fuel gas auxiliary heating type flue gas heat exchange frost restraining type heat pump air conditioning system comprises a compressor, a condensation heat exchanger, an evaporator, a vacuum heat exchanger and an air preheater. A vacuum heat exchanger is additionally arranged between a condensation heat exchanger and a heat using tail end, direct combustion heat compensation is conducted on flowing hot water through a fuel gas heat compensation unit of the vacuum heat exchanger, and the water supply temperature of the system under the heating working condition in winter is ensured. High-temperature flue gas exhausted during heat compensation can enter the air preheater to exchange heat with introduced low-temperature air, and the preheated air is blown to the evaporator, so that frosting of the heat pump can be effectively inhibited, the starting time prolonged due to defrosting in extreme weather is shortened, and the heating efficiency of the heat pump is improved; when the air conditioner is started in extreme weather in winter, hot water of the air conditioner can be preheated through the fuel gas heat compensation unit, and frost on the surface of the evaporator is removed through flue gas heat exchange, so that the defrosting time of the heat pump is effectively shortened, the supply speed of the hot water is increased, and the power consumption required by defrosting is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of building air conditioning systems, and in particular to a gas-assisted heat-exchange, flue gas heat-exchange, and frost-suppression heat pump air conditioning system. Background Art

[0002] The urbanization level in hot summer and cold winter areas is high, and the heating demand for production, office, and life and the demand for domestic hot water have increased sharply, and the energy consumption of buildings remains high. At present, the air-conditioning systems of large buildings in hot summer and cold winter areas mostly use water system central air-conditioning. The summer cold source of water system central air-conditioning mostly uses electric refrigeration chillers, and the winter heat source mostly uses gas boilers. The pressure of ensuring power supply and gas supply in the region in winter is relatively large, and the gas cost is also rising year by year. Therefore, it has become a new trend to use air-cooled heat pump units to replace gas boilers.

[0003] The winter supply and return water temperature of traditional air-cooled heat pump air conditioners is generally 45 / 40℃, and the rated heating capacity on its nameplate is for operating conditions when the outdoor ambient temperature is 7℃. When the outdoor temperature is below 7℃, the heating capacity will decay. When the outdoor temperature is below 0℃, the heating capacity of conventional air-cooled heat pump units will decay more seriously. At present, extreme weather is becoming more and more frequent, and improving the winter heating efficiency of air-cooled heat pump units has become an important issue in the heat pump field. Summary of the invention

[0004] In view of this, an embodiment of the present invention provides a gas-assisted flue gas heat exchange and frost suppression type heat pump air-conditioning system to solve the technical problems that the existing air-cooled heat pump units have a decreased heating efficiency in low temperature environments in winter, poor heating effects in extreme weather conditions, and high heating energy consumption.

[0005] A gas-assisted flue gas heat exchange and frost suppression heat pump air conditioning system provided in an embodiment of the present invention comprises a compressor, a condensing heat exchanger, an evaporator, a vacuum heat exchanger and an air preheater; the refrigerant outlet of the compressor is connected to the refrigerant inlet of the condensing heat exchanger through a four-way reversing valve, the refrigerant outlet of the condensing heat exchanger is connected to the refrigerant inlet of the evaporator through an expansion valve, and the refrigerant outlet of the evaporator is connected to the refrigerant inlet of the compressor through the four-way reversing valve;

[0006] The water outlet of the condensing heat exchanger is connected to the water inlet of the vacuum heat exchanger through a first electric three-way valve, the water outlet of the vacuum heat exchanger is connected to the water inlet of the heat-using end, the water outlet of the heat-using end is connected to the water inlet of the condensing heat exchanger through a second electric three-way valve, and the first electric three-way valve is connected to the second electric three-way valve; the vacuum heat exchanger is provided with a gas heating unit for auxiliary heating of the hot water flowing through the vacuum heat exchanger;

[0007] The air preheater is provided with an air passage and a flue gas passage for exchanging heat with the air passage; the flue gas inlet of the flue gas passage is connected to the flue gas exhaust port of the gas supplementary heating unit, and the flue gas outlet of the flue gas passage is connected to a flue gas exhaust pipe; the air outlet of the air passage is connected to the air inlet of the evaporator, and the air inlet of the air passage is provided with a fan for blowing the preheated air to the evaporator.

[0008] Furthermore, in winter heating conditions, the refrigerant absorbs external heat through the evaporator, enters the condensing heat exchanger for heat exchange after being compressed by the compressor, and then passes through the expansion valve and enters the evaporator for refrigerant circulation after being cooled by heat exchange;

[0009] At this time, the hot water discharged from the condensing heat exchanger enters the vacuum heat exchanger through the first electric three-way valve, and enters the heat-using end through the vacuum heat exchanger. After the hot water is cooled by heat exchange at the heat-using end, it re-enters the condensing heat exchanger through the second electric three-way valve for hot water circulation.

[0010] Furthermore, a first temperature sensor is provided between the water outlet of the condensing heat exchanger and the first electric three-way valve; when the temperature of the hot water discharged from the condensing heat exchanger is lower than a preset value, the gas heating unit automatically operates to auxiliary heat the hot water flowing through the vacuum heat exchanger; when the gas heating unit is in operation, the high-temperature flue gas discharged enters the air preheater to exchange heat with the low-temperature air introduced, and the preheated air is blown to the evaporator by the fan.

[0011] Furthermore, a second temperature sensor is provided between the water outlet of the vacuum heat exchanger and the water inlet of the heat-using end.

[0012] Furthermore, the gas heating unit is equipped with a third temperature sensor for real-time monitoring of the outdoor ambient temperature; when the outdoor ambient temperature is lower than a preset value and the compressor is initially started, the four-way reversing valve is reversed to allow the refrigerant to circulate in reverse; at this time, the water outlet of the heat-using end is connected to the water inlet of the vacuum heat exchanger through the second electric three-way valve and the first electric three-way valve, and the hot water is cooled by heat exchange at the heat-using end, and then enters the vacuum heat exchanger through the second electric three-way valve and the first electric three-way valve, and then enters the heat-using end for hot water circulation after being heated by the vacuum heat exchanger; the gas heating unit automatically operates to assist in heating the hot water flowing through the vacuum heat exchanger; the high-temperature flue gas discharged during the operation of the gas heating unit enters the air preheater to exchange heat with the low-temperature air introduced, and the preheated air is blown to the evaporator by the fan.

[0013] Furthermore, a fourth temperature sensor is provided between the water outlet of the heat-using end and the second electric three-way valve; and a fifth temperature sensor is provided between the second electric three-way valve and the water inlet of the condensing heat exchanger.

[0014] Furthermore, the air preheater adopts a BxB plate heat exchanger.

[0015] The embodiments of the present invention have the following beneficial effects:

[0016] 1. Add a vacuum heat exchanger between the condensing heat exchanger and the heat-using end (heat user) of the original air-cooled heat pump air-conditioning system, and directly burn the hot water flowing through it through the gas heating unit of the vacuum heat exchanger to ensure the water supply temperature of the system under winter heating conditions; at the same time, the high-temperature flue gas discharged during heating can enter the air preheater to exchange heat with the incoming low-temperature air, and the preheated air is blown to the evaporator, which can effectively inhibit the frosting of the heat pump, reduce the start-up time extended by defrosting in extreme weather, improve the heating efficiency of the heat pump, make full use of the waste heat of the gas, and solve the problem of "white smoke" in winter heating by gas boilers.

[0017] 2. When the system is started in extreme winter weather, the air-conditioning hot water can be preheated through the gas heating unit of the vacuum heat exchanger, and the frost on the surface of the evaporator can be removed by flue gas heat exchange, which effectively shortens the defrosting time of the heat pump, speeds up the supply of hot water, and reduces the power consumption required for defrosting. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0019] Figure 1 is a system flow chart of an embodiment of the present invention;

[0020] The numbers in the figure represent:

[0021] 1. Compressor; 2. Condensing heat exchanger; 3. Evaporator; 4. Vacuum heat exchanger; 5. Air preheater; 6. Four-way reversing valve; 7. Expansion valve; 8. First electric three-way valve; 9. Heat terminal; 10. Second electric three-way valve; 11. Gas heating unit; 12. Smoke exhaust pipe; 13. Fan; 14. First temperature sensor; 15. Second temperature sensor; 16. Third temperature sensor; 17. Fourth temperature sensor; 18. Fifth temperature sensor. DETAILED DESCRIPTION

[0022] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present invention. In addition, it should be understood that the specific implementation methods described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention. In the present invention, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Thus, the features defined as "first", "second", etc. may explicitly or implicitly include one or more features.

[0023] See also Figure 1 As shown, an embodiment of the present invention provides a gas-assisted flue gas heat exchange frost suppression type heat pump air conditioning system, comprising a compressor 1, a condensing heat exchanger 2, an evaporator 3, a vacuum heat exchanger 4 and an air preheater 5. The refrigerant outlet of the compressor 1 is connected to the refrigerant inlet of the condensing heat exchanger 2 through a four-way reversing valve 6, the refrigerant outlet of the condensing heat exchanger 2 is connected to the refrigerant inlet of the evaporator 3 through an expansion valve 7, and the refrigerant outlet of the evaporator 3 is connected to the refrigerant inlet of the compressor 1 through a four-way reversing valve 6.

[0024] The water outlet of the condensing heat exchanger 2 is connected to the water inlet of the vacuum heat exchanger 4 through the first electric three-way valve 8, and the water outlet of the vacuum heat exchanger 4 is connected to the water inlet of the heat-using terminal 9 (heat user), and the water outlet of the heat-using terminal 9 is connected to the water inlet of the condensing heat exchanger 2 through the second electric three-way valve 10, and the first electric three-way valve 8 is connected to the second electric three-way valve 10. The vacuum heat exchanger 4 is provided with a gas heating unit 11, which can assist in heating the hot water flowing through the vacuum heat exchanger 4.

[0025] An air passage and a flue gas passage for heat exchange with the air passage are provided in the air preheater 5. The flue gas inlet of the flue gas passage is connected to the exhaust port of the gas heating unit 11, and the flue gas outlet of the flue gas passage is connected to the exhaust pipe 12. The air outlet of the air passage is connected to the air inlet of the evaporator 3, and the air inlet of the air passage is provided with a fan 13, which can blow the preheated air to the evaporator 3. For reference, the air preheater 5 can adopt a BxB plate heat exchanger, which has a compact structure and high heat exchange efficiency, and can effectively recover the waste heat in the flue gas.

[0026] Under winter heating conditions, the refrigerant absorbs external heat through the evaporator 3, is compressed by the compressor 1, and enters the condensing heat exchanger 2 for heat exchange. After the refrigerant is cooled by heat exchange, it passes through the expansion valve 7 and then enters the evaporator 3 for refrigerant circulation.

[0027] At this time, the hot water discharged from the condensing heat exchanger 2 enters the vacuum heat exchanger 4 through the first electric three-way valve 8, and enters the heat-using end 9 through the vacuum heat exchanger 4. After the hot water is cooled by heat exchange at the heat-using end 9, it re-enters the condensing heat exchanger 2 through the second electric three-way valve 10 for hot water circulation.

[0028] A first temperature sensor 14 is provided between the water outlet of the condensing heat exchanger 2 and the first electric three-way valve 8. When the first temperature sensor 14 detects that the temperature of the hot water discharged from the condensing heat exchanger 2 is not lower than a preset value (e.g., 50°C), the gas heating unit 11 does not start, and the hot water directly passes through the vacuum heat exchanger 4 and enters the heat-using end 9. When the first temperature sensor 14 detects that the temperature of the hot water discharged from the condensing heat exchanger 2 is lower than the preset value, the gas heating unit 11 automatically operates to perform auxiliary heating on the hot water flowing through the vacuum heat exchanger 4 to ensure the heating effect of the heat-using end 9. At the same time, the high-temperature flue gas discharged from the gas heating unit 11 during operation enters the air preheater 5 to exchange heat with the low-temperature air introduced, and the low-temperature flue gas after heat exchange is discharged through the exhaust pipe 12, and the preheated air is blown to the evaporator 3 by the fan 13, thereby effectively suppressing the frosting of the heat pump, reducing the start-up time extended by defrosting in extreme weather, and improving the heating efficiency of the heat pump.

[0029] Furthermore, a second temperature sensor 15 is provided between the water outlet of the vacuum heat exchanger 4 and the water inlet of the heat-using end 9 , and the second temperature sensor 15 can detect the temperature of the hot water flowing out of the vacuum heat exchanger 4 so as to adjust the gas heating unit 11 in linkage.

[0030] The gas heating unit 11 is equipped with a third temperature sensor 16 for real-time monitoring of the outdoor ambient temperature. When the compressor 1 is initially started, if the third temperature sensor 16 detects that the outdoor ambient temperature is lower than a preset value (e.g., 0°C), the four-way reversing valve 6 is reversed to allow the refrigerant to circulate in reverse to increase the surface temperature of the evaporator 3 and dissipate heat and defrost. At this time, the water outlet of the heat-using end 9 is connected to the water inlet of the vacuum heat exchanger 4 through the second electric three-way valve 10 and the first electric three-way valve 8. After the hot water is cooled by heat exchange at the heat-using end 9, it enters the vacuum heat exchanger 4 through the second electric three-way valve 10 and the first electric three-way valve 8, and then enters the heat-using end 9 for hot water circulation after being supplemented by the vacuum heat exchanger 4; the gas supplementary heating unit 11 automatically operates to auxiliary heat the hot water flowing through the vacuum heat exchanger 4, and the high-temperature flue gas discharged during operation enters the air preheater 5 to exchange heat with the low-temperature air introduced, and the preheated air is blown to the evaporator 3 by the fan 13 to defrost the evaporator 3, which effectively shortens the defrosting time of the heat pump, speeds up the supply speed of hot water, and reduces the power consumption required for defrosting. When the evaporator 3 is defrosted, the four-way reversing valve 6 switches the refrigerant back to the heating cycle, the passage between the second electric three-way valve 10 and the first electric three-way valve 8 is closed, the water outlet of the condensing heat exchanger 2 is connected to the water inlet of the vacuum heat exchanger 4 through the first electric three-way valve 8, and the water outlet of the heat terminal 9 is connected to the water inlet of the condensing heat exchanger 2 through the second electric three-way valve 10.

[0031] Furthermore, a fourth temperature sensor 17 is provided between the water outlet of the heat terminal 9 and the second electric three-way valve 10, and a fifth temperature sensor 18 is provided between the second electric three-way valve 10 and the water inlet of the condensing heat exchanger 2, for monitoring the temperature of the hot water discharged after heat exchange at the heat terminal 9.

[0032] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the technical solutions and core ideas of the present invention. Ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some of the technical features therein with equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A gas-assisted flue gas heat exchange and frost suppression heat pump air conditioning system, characterized in that: It includes a compressor, a condensing heat exchanger, an evaporator, a vacuum heat exchanger and an air preheater; the refrigerant outlet of the compressor is connected to the refrigerant inlet of the condensing heat exchanger through a four-way reversing valve, the refrigerant outlet of the condensing heat exchanger is connected to the refrigerant inlet of the evaporator through an expansion valve, and the refrigerant outlet of the evaporator is connected to the refrigerant inlet of the compressor through the four-way reversing valve; The water outlet of the condensing heat exchanger is connected to the water inlet of the vacuum heat exchanger through a first electric three-way valve, the water outlet of the vacuum heat exchanger is connected to the water inlet of the heat-using end, the water outlet of the heat-using end is connected to the water inlet of the condensing heat exchanger through a second electric three-way valve, and the first electric three-way valve is connected to the second electric three-way valve; the vacuum heat exchanger is provided with a gas heating unit for auxiliary heating of the hot water flowing through the vacuum heat exchanger; The air preheater is provided with an air passage and a flue gas passage for exchanging heat with the air passage; the flue gas inlet of the flue gas passage is connected to the flue gas exhaust port of the gas supplementary heating unit, and the flue gas outlet of the flue gas passage is connected to a flue gas exhaust pipe; the air outlet of the air passage is connected to the air inlet of the evaporator, and the air inlet of the air passage is provided with a fan for blowing the preheated air to the evaporator.

2. A gas-assisted flue gas heat exchange and frost suppression heat pump air conditioning system according to claim 1, characterized in that: Under winter heating conditions, the refrigerant absorbs external heat through the evaporator, enters the condensing heat exchanger for heat exchange after being compressed by the compressor, and after the refrigerant is cooled by heat exchange, enters the evaporator again through the expansion valve for refrigerant circulation; At this time, the hot water discharged from the condensing heat exchanger enters the vacuum heat exchanger through the first electric three-way valve, and enters the heat-using end through the vacuum heat exchanger. After the hot water is cooled by heat exchange at the heat-using end, it re-enters the condensing heat exchanger through the second electric three-way valve for hot water circulation.

3. A gas-assisted flue gas heat exchange and frost suppression heat pump air conditioning system according to claim 2, characterized in that: A first temperature sensor is provided between the water outlet of the condensing heat exchanger and the first electric three-way valve; when the temperature of the hot water discharged from the condensing heat exchanger is lower than a preset value, the gas heating unit automatically operates to auxiliary heat the hot water flowing through the vacuum heat exchanger; when the gas heating unit is in operation, the high-temperature flue gas discharged enters the air preheater to exchange heat with the low-temperature air introduced, and the preheated air is blown to the evaporator by the fan.

4. A gas-assisted flue gas heat exchange and frost suppression heat pump air conditioning system according to claim 3, characterized in that: A second temperature sensor is provided between the water outlet of the vacuum heat exchanger and the water inlet of the heat-using end.

5. A gas-assisted flue gas heat exchange and frost suppression heat pump air conditioning system according to claim 4, characterized in that: The gas heating unit is equipped with a third temperature sensor for real-time monitoring of the outdoor ambient temperature; when the outdoor ambient temperature is lower than a preset value and the compressor is initially started, the four-way reversing valve is reversed to allow the refrigerant to circulate in reverse; at this time, the water outlet of the heat-using end is connected to the water inlet of the vacuum heat exchanger through the second electric three-way valve and the first electric three-way valve, and the hot water enters the vacuum heat exchanger through the second electric three-way valve and the first electric three-way valve after heat exchange and cooling at the heat-using end, and then enters the heat-using end for hot water circulation after heat supplementation in the vacuum heat exchanger; the gas heating unit automatically operates to assist in heating the hot water flowing through the vacuum heat exchanger; the high-temperature flue gas discharged during the operation of the gas heating unit enters the air preheater to exchange heat with the low-temperature air introduced, and the preheated air is blown to the evaporator by the fan.

6. A gas-assisted flue gas heat exchange and frost suppression heat pump air conditioning system according to claim 5, characterized in that: A fourth temperature sensor is provided between the water outlet of the heat-using end and the second electric three-way valve; a fifth temperature sensor is provided between the second electric three-way valve and the water inlet of the condensing heat exchanger.

7. The gas-assisted flue gas heat exchange and frost suppression heat pump air conditioning system according to claim 1, characterized in that: The air preheater adopts a BxB plate heat exchanger.

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