CN103292513B - Driven by Solar Energy list economic benefits and social benefits coupled mode lithium bromide refrigerator - Google Patents

Abstract

The invention provides a solar-driven single and double-effect coupled lithium bromide refrigerator, including a solar medium-temperature heat collector, a gas boiler, a hot water storage tank, a heat collection circulation pump, a high-temperature heat exchanger, a low-temperature heat exchanger, and a lithium bromide solution pump , absorber, refrigerant water circulation pump, evaporator, heat exchange terminal, air-conditioned room, expansion valve, cooling water circulation pump, cooling tower, condenser, low pressure generator, high pressure generator, hot water circulation pump, first valve, second The second valve, the third valve, the fourth valve, the fifth valve, the sixth valve, the seventh valve, and the eighth valve. According to the characteristics of the solar heat collection system, the invention can fully and efficiently utilize solar energy by switching between single-effect and double-effect systems, reduce the consumption of primary energy by conventional gas-driven lithium bromide refrigerators, and is environmentally friendly.

Description

Solar-driven single-effect coupled lithium bromide refrigerator

technical field

The invention relates to the technical field of solar energy utilization and air conditioning, in particular to a solar-driven single-effect coupled lithium bromide refrigerator.

Background technique

Solar energy is a widely distributed and clean renewable energy, which is expected to play a more important role in the energy structure of the future society. Among them, using solar energy for heating, heating and cooling is an important way to realize large-scale and low-cost utilization of solar energy. In particular, with the large-scale application of solar heat collection and heating systems in recent years, the phenomenon of excess solar heat in summer is very prominent. Scholars from all over the world are actively looking for effective ways to use solar energy for air conditioning and cooling in summer, with the purpose of improving solar energy collection. On the other hand, it can open up a new technical way to use solar energy to solve the cooling demand of air conditioners. The biggest advantage of solar air conditioning and refrigeration is that it has good seasonal matching. The hotter the weather and the more cooling is needed, the better the solar radiation conditions and the greater the cooling capacity of the solar refrigeration system.

Since solar collectors are mainly used in hot water systems at present, and the heat collection temperature is usually below 90°C, the research and application of solar air conditioners in the past focused on the solar air conditioner technology that matches ordinary solar collectors, especially those with relatively mature production technologies. Single-effect absorption refrigeration units are widely used. However, solar air conditioners combined with low-temperature solar heat collection technology also have some problems. On the one hand, due to the low temperature of the heat source (60-90°C), the matching absorption or adsorption refrigeration unit generally has a cooling thermal power COP of 0.4-0.7. On the other hand, in order to ensure the continuity of solar air-conditioning, gas or oil-fired boilers are generally used as auxiliary heat sources. For solar air-conditioning systems with low solar guarantee rate, they often lose their due advantages due to low thermal COP (compared with conventional air-conditioning systems). To match the lithium bromide absorption air conditioner, you can choose a double-effect product with a refrigeration thermal COP of 1.2, but it requires a heat source of 150°C. The conventional direct-fired lithium bromide absorption refrigerator is a lithium bromide absorption double-effect refrigeration driven by a fuel or gas boiler. machine. If it is driven by solar energy, the system needs to match the corresponding medium temperature collector.

In addition, for solar collectors, limited by the level of solar radiation, the heating temperature of the collector is lower in the morning and evening during the day, and reaches the highest around noon. For solar air-conditioning systems driven by medium-temperature collectors, the collector temperature can meet the requirements of double-effect cooling operation generally near noon, and can only meet the operating conditions of single-effect cooling in the morning and part of the afternoon. Therefore, to prolong the cooling time of the solar air-conditioning and refrigeration system, the best way is to adopt the operation mode of single-effect/double-effect automatic switching, and automatically switch between single-effect and double-effect modes according to the temperature change of the solar collector heating during the day. Switch to meet high-efficiency, long-term cooling needs.

Through the retrieval of prior art documents, it is found that the Chinese patent application publication number is: CN101886854A, and the invention name is: single-double-effect absorption refrigerator. A single-effect and double-effect switching refrigerator is proposed, and the focus is on how to control the operation capacity of the intermediate dilute solution pump according to the change of refrigeration load. From a structural point of view, it adds a generator and a condenser for single-effect operation on the basis of the original direct-fired double-effect absorption refrigerator, and the generator for single-effect operation requires other heat source water for supply. And when the single effect is running, the high and low pressure generators and condensers of the original direct-fired double effect unit do not work, and the utilization rate of system components is low.

The Chinese patent application publication number is: CN101231043A, and the title of the invention is: single and double effect absorption refrigerator and its operation control method. The structure of the proposed single and double effect refrigerator is similar to the single and double effect absorption refrigerator in CN10188854A, and additional generators and condensers for single effect operation are also added. Moreover, the double-effect operation only relies on the gas boiler as the heat source, and does not involve the utilization of solar energy, so the primary energy consumption is large.

The Chinese patent application publication number is: CN101526283A, and the title of the invention is: flue gas hot water single and double effect compound lithium bromide absorption chiller, chiller and hot water unit. The main difference between the proposed flue gas hot water single and double-effect compound lithium bromide absorption chiller and hot water unit and the technical solutions disclosed by the above-mentioned publication numbers CN101231043A and CN101886854A is that it only adds a single-effect unit to the original double-effect unit. The running hot water generator has a simpler structure than the above two. The main difference between it and the present invention is that the heat source of its double-effect operation uses other devices to generate high-temperature flue gas, which belongs to the field of waste heat utilization, while the heat source of the double-effect operation in the present invention is provided by a solar medium-temperature heat collector, which is a new energy and In the field of renewable resource utilization, and due to the different forms of heat sources of the two generators, their structural forms will also have significant differences. And it adds an additional solution pump during single-effect operation, but in the present invention, the function is realized only by the switching of pipeline valves.

Contents of the invention

The present invention aims at the above problems and deficiencies in the prior art, and proposes a solar-driven single-effect coupled lithium bromide absorption refrigerator. By adding a single-effect hot water heat exchanger to the low-pressure generator and controlling the opening and closing of related valves, the switching between the single-effect and double-effect working conditions of the refrigeration unit under different water temperatures is realized. It can make full use of the grade of hot water in the solar thermal collection system at different time periods, realize automatic switching between single and double effects, efficiently use solar energy for cooling, and solve the problem of excess heat in the solar system in summer, and the solar thermal collection system can also provide domestic hot water at the same time Can be used for heating. When the solar radiation is insufficient but there is a cooling demand, the gas boiler is used to drive the double-effect cooling operation.

The solar-driven single and double-effect coupled lithium bromide refrigerator provided by the present invention includes a solar medium-temperature heat collector 1, a gas boiler 3, a hot water storage tank 6, a heat collecting circulation pump 7, a high-temperature heat exchanger 9, and a low-temperature heat exchanger 10 , lithium bromide solution pump 13, absorber 14, refrigerant water circulation pump 15, evaporator 16, heat exchange terminal 17, air conditioning room 18, expansion valve 19, cooling water circulation pump 20, cooling tower 21, condenser 22, low pressure generator 23 , high pressure generator 24, hot water circulation pump 26, first valve 2, second valve 4, third valve 5, fourth valve 8, fifth valve 11, sixth valve 12, seventh valve 25, eighth valve 27, wherein: the solar medium-temperature heat collector 1 is connected with the hot water storage tank 6 and the heat collection circulation pump 7 to form a heat collection loop; the high-pressure generator 24 is connected to the low-pressure generator 23, and the low-pressure generator 23 is connected to the condenser 22, and the 22 is connected to the evaporator 16 through the expansion valve 19, the evaporator 16 is connected to the absorber 14, the absorber 14 is connected to the high temperature heat exchanger 9 and the low temperature heat exchanger 10 respectively through the lithium bromide solution pump 13, and the high temperature heat exchanger 9 is connected to the high pressure generator 24 connected, the low-temperature heat exchanger 10 is connected with the low-pressure generator 23 to form a single and double-effect lithium bromide refrigerator; the cooling tower 21 is connected with the absorber 14 and the condenser 22 through the cooling water circulation pump 20 to form a cooling water loop; The terminal 17 is placed in the air-conditioned room 18, and the heat exchange terminal 17 is connected to the evaporator 16 to form a terminal circulation loop; the first valve (2) is respectively connected to the solar medium temperature heat collector 1 and the hot water storage tank 6; the second valve 4 is respectively Connect the gas boiler 3 and the high pressure generator 24; the third valve 5 connects the gas boiler 3 and the high pressure generator 24 respectively; the fourth valve 8 connects the hot water storage tank 6 and the high pressure generator 24 respectively; the fifth valve 11 connects the lithium bromide solution respectively The pump 13 and the high-temperature heat exchanger 9; the sixth valve 12 is respectively connected to the lithium bromide solution pump 13 and the low-temperature heat exchanger 10; the seventh valve 25 is respectively connected to the hot water circulation pump 26 and the low-pressure generator 23; the eighth valve 27 is respectively connected to the high-pressure The generator 24 and the solar medium temperature heat collector 1; both ends of the refrigerant water circulation pump 15 are connected to the evaporator 16, and both ends of the lithium bromide solution pump 13 are connected to the absorber 14.

Preferably, two sets of heat exchangers are arranged in the low-pressure generator 23, one set is a steam heat exchanger 2307, and the other set is a hot water heat exchanger 2304, wherein: the steam heat exchanger 2307 exchanges heat with hot water The generators 2304 are placed in the low-pressure generator 23, the steam heat exchanger 2307 is respectively connected to the high-pressure generator 24 and the condenser 22, and the hot water heat exchanger 2304 is connected to the hot water storage tank 6 through the hot water circulation pump 26.

Preferably, there are three different modes of operation:

In the first mode, the solar energy drives the single and double effect coupled lithium bromide refrigerator to operate in double effect: the hot water generated by the solar medium temperature collector 1 directly enters the high pressure generator 24;

In the second mode, the single-effect operation of the single-effect coupled lithium bromide refrigerator driven by solar energy: the hot water generated by the solar medium temperature collector 1 enters the hot water generator in the low-pressure generator 23;

In the third mode, the gas boiler drives the double-effect coupled lithium bromide refrigerator for double-effect operation: the hot water generated by the gas boiler 3 enters the high-pressure generator 24 .

Preferably, the corresponding operating mode is automatically selected according to the outlet temperature of the solar medium-temperature heat collector 1, and the switch of the relevant water pump valve is controlled.

Preferably, the hot water generated by the solar medium-temperature heat collector 1 is used as the main heat source, and the gas-fired boiler 3 is used as a supplement when the irradiation conditions are not good.

Compared with the prior art, the present invention can use the single-effect and double-effect switching of the system according to the characteristics of the solar heat collection system, fully and efficiently utilize the solar energy, reduce the consumption of primary energy by conventional gas-driven lithium bromide refrigerators, and be environmentally friendly.

Description of drawings

Other characteristics, objects and advantages of the present invention will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings:

Fig. 1 is a schematic flow sheet of a solar-driven single-effect coupling type lithium bromide refrigerator of the present invention;

Fig. 2 is the detailed diagram of medium and low pressure generator of the present invention;

Fig. 3 is a control logic diagram of switching between single and double effects in the present invention.

Detailed ways

The present invention will be described in detail below in conjunction with specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2 . Fig. 1 is a flow diagram of the present invention, the solar-driven single-double-effect coupled lithium bromide refrigerator includes: a solar medium-temperature heat collector 1, a gas-fired boiler 3, a hot water storage tank 6, a heat-collecting circulation pump 7, and a high-temperature heat exchanger 9. Low temperature heat exchanger 10, lithium bromide solution pump 13, absorber 14, refrigerant water circulation pump 15, evaporator 16, heat exchange terminal 17, air conditioning room 18, expansion valve 19, cooling water circulation pump 20, cooling tower 21, condensation Device 22, low pressure generator 23, high pressure generator 24, hot water circulation pump 26, first valve 2, second valve 4, third valve 5, fourth valve 8, fifth valve 11, sixth valve 12, first valve Seven valves 25, eighth valves 27. In the following, the present invention will be elaborated on various operating modes in conjunction with the accompanying drawings. Fig. 2 shows dilute solution spray port 2301, heat source hot water inlet 2302, heat source hot water outlet 2303, hot water heat exchanger 2304, concentrated solution outlet port 2305, high pressure generator steam outlet 2306, steam heat exchanger 2307, High pressure generator steam inlet 2308, steam outlet 2309.

1. The refrigerator is driven by solar energy, the second valve 4 and the third valve 5 are closed:

(1) The water temperature at the outlet of solar medium temperature collector 1 satisfies double-effect operation: the fourth valve 8 is opened, the fifth valve 11 is opened, the sixth valve 12 is opened, the eighth valve 27 is opened, the first valve 2 is closed, and the seventh valve 25 closure. The hot water at the outlet of the solar medium-temperature heat collector 1 enters the high-pressure generator 24, and the lithium bromide solution in the high-pressure generator 24 is heated to generate high-temperature water vapor, and its concentration increases. The high-temperature water vapor produced by the high-pressure generator 24 enters the low-pressure generator 23 connected to it through the pipeline, and the lithium bromide solution in the low-pressure generator 23 is heated again and enters the condenser 22 to be condensed into liquid water. The water vapor produced after the lithium bromide solution in the low-pressure generator 23 is heated also enters the condenser 22 and is condensed into liquid water. The liquid water in the condenser 22 enters the evaporator 16 with lower pressure after being throttled and depressurized by the expansion valve 19, evaporates and absorbs the heat from the heat exchange terminal 17 in the air-conditioned room 18, reduces the temperature of the medium therein, and passes through the cooling Agent water circulation pump 15 realizes continuous refrigeration. The low-pressure steam evaporated in the evaporator 16 enters the absorber 14 connected thereto, and is absorbed by the lithium bromide concentrated solution from the high-pressure generator 24 and the low-pressure generator 23, so that the concentrated solution entering the absorber 14 is diluted into a dilute solution, And sent to high temperature heat exchanger 9 and low temperature heat exchanger 10 by lithium bromide solution pump 13. The lithium bromide solution in the high-pressure generator 24 releases water vapor and its concentration increases, and enters the high-temperature heat exchanger 9 through the pipeline, and enters the absorber 14 after completing heat exchange with the dilute solution from the absorber 14 . The dilute solution in the absorber 14 passes through the high-temperature heat exchanger 9 and enters the high-pressure generator 24 to continue the process. Similarly, the lithium bromide solution in the low-pressure generator 23 releases water vapor and its concentration increases, and enters the low-temperature heat exchanger 10 through a pipeline, and enters the absorber 14 after completing heat exchange with the dilute solution from the absorber 14 . The dilute solution in the absorber 14 passes through the low-temperature heat exchanger 10 and enters the low-pressure generator 23 to continue the process. The hot water coming out of the high pressure generator 24 enters the hot water storage tank 6 . The heat collection circulation pump 7 sends the water in the hot water storage tank 6 into the solar medium temperature heat collector 1 for reheating to complete the heat collection cycle. The cooling water circulation pump 20 sends the cooling water in the cooling tower 21 to the absorber 14 and the condenser 22 to complete the heat exchange, and then enters the cooling tower 21 again for evaporative cooling to complete the cooling water cycle.

(2) The water temperature at the outlet of solar medium temperature collector 1 satisfies single-effect operation: the first valve 2 is opened, the sixth valve 12 is opened, the seventh valve 25 is opened, the fourth valve 8 is closed, the fifth valve 11 is closed, and the eighth valve 27 closure. The hot water at the outlet of the solar medium-temperature heat collector 1 enters the hot water storage tank 6 . The hot water in the hot water storage tank 6 is sent to the low-pressure generator 23 by the hot water circulation pump 26, where the lithium bromide solution is heated, and then returned to the hot water storage tank 6 through the pipeline. The water vapor generated after the lithium bromide solution in the low-pressure generator 23 is heated enters the condenser 22 and is condensed into liquid water. The liquid water in the condenser 22 enters the evaporator 16 with lower pressure after being throttled and depressurized by the expansion valve 19, evaporates and absorbs the heat from the heat exchange terminal 17 in the air-conditioned room 18, reduces the temperature of the medium therein, and passes through the cooling Agent water circulation pump 15 realizes continuous refrigeration. The low-pressure water vapor evaporated in the evaporator 16 enters the absorber 14 connected to it, and is absorbed by the lithium bromide concentrated solution from the low-pressure generator 23, so that the concentrated solution entering the absorber 14 is diluted into a dilute solution, and is pumped by the lithium bromide solution pump 13 sent to the low temperature heat exchanger 10. The lithium bromide solution in the low-pressure generator 23 releases water vapor and its concentration increases, and enters the low-temperature heat exchanger 10 through a pipeline, and enters the absorber 14 after completing heat exchange with the dilute solution from the absorber 14 . The dilute solution in the absorber 14 passes through the low-temperature heat exchanger 10 and enters the low-pressure generator 23 to continue the process. The heat collection circulation pump 7 sends the water in the hot water storage tank 6 into the solar medium temperature heat collector 1 for reheating to complete the heat collection cycle. The cooling water circulation pump 20 sends the cooling water in the cooling tower 21 to the absorber 14 and the condenser 22 to complete the heat exchange, and then enters the cooling tower again for evaporative cooling, thus completing the cooling water cycle.

2. When the solar radiation is not enough to drive the refrigerator, it is driven by the gas boiler 3: the second valve 4 is opened, the third valve 5 is opened, the fourth valve 8 is closed, the seventh valve 25 is closed, and the eighth valve 27 is closed. The high-temperature hot water generated by the gas boiler 3 directly enters the high-pressure generator 24 for double-effect refrigeration. The operation of other components is the same as that of the solar-driven double-effect operation, and the heat source is switched to the boiler. The solar collector cycle can operate as usual to supply domestic hot water. This mode is only used as an auxiliary mode in rainy days when the sun is insufficient or at night.

Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art may make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention.

Claims (4)

1. A solar-driven single-effect coupled lithium bromide refrigerator, characterized in that it comprises a solar medium-temperature heat collector (1), a gas boiler (3), a hot water storage tank (6), and a heat-collecting circulation pump (7) , high temperature heat exchanger (9), low temperature heat exchanger (10), lithium bromide solution pump (13), absorber (14), refrigerant water circulation pump (15), evaporator (16), heat exchange terminal (17) , air-conditioned room (18), expansion valve (19), cooling water circulation pump (20), cooling tower (21), condenser (22), low pressure generator (23), high pressure generator (24), hot water circulation pump (26), the first valve (2), the second valve (4), the third valve (5), the fourth valve (8), the fifth valve (11), the sixth valve (12), the seventh valve ( 25), the eighth valve (27), wherein: the solar medium temperature heat collector (1) is connected with the hot water storage tank (6) and the heat collection circulation pump (7) to form a heat collection loop; the high pressure generator (24) is connected to The low-pressure generator (23), the low-pressure generator (23) is connected to the condenser (22), the condenser (22) is connected to the evaporator (16) through the expansion valve (19), and the evaporator (16) is connected to the absorber (14), The absorber (14) is connected to the high-temperature heat exchanger (9) and the low-temperature heat exchanger (10) respectively through the lithium bromide solution pump (13), and the high-temperature heat exchanger (9) is connected to the high-pressure generator (24). The device (10) is connected with the low-pressure generator (23) to form a single- and double-effect lithium bromide refrigerator; the cooling tower (21) is connected to the absorber (14) and the condenser (22) respectively through the cooling water circulation pump (20) to form a cooling Water loop; the heat exchange terminal (17) is placed in the air-conditioned room (18), and the heat exchange terminal (17) is connected with the evaporator (16) to form a terminal circulation loop; the first valve (2) is respectively connected to the solar medium temperature heat collector (1) and the hot water storage tank (6); the second valve (4) is respectively connected to the gas boiler (3) and the high pressure generator (24); the third valve (5) is respectively connected to the gas boiler (3) and the high pressure generator device (24); the fourth valve (8) is respectively connected to the hot water storage tank (6) and the high pressure generator (24); the fifth valve (11) is respectively connected to the lithium bromide solution pump (13) and the high temperature heat exchanger (9) ; The sixth valve (12) is respectively connected to the lithium bromide solution pump (13) and the low-temperature heat exchanger (10); the seventh valve (25) is connected to the hot water circulation pump (26) and the low-pressure generator (23) respectively; the eighth valve (27) respectively connect the high-voltage generator (24) and the solar heat collector (1); both ends of the refrigerant water circulation pump (15) are connected to the evaporator (16), and both ends of the lithium bromide solution pump (13) are connected to the absorber (14); The low-pressure generator (23) is provided with two sets of heat exchangers, one set is a steam heat exchanger (2307), and the other set is a hot water heat exchanger (2304), wherein: the steam heat exchanger (2307) and the hot water heat exchanger (2304) are placed in the low-pressure generator (23), the steam heat exchanger (2307) is respectively connected to the high-pressure generator (24) and the condenser (22), and the hot water heat exchanger (2304) Link to each other with hot water storage tank (6) through hot water circulation pump (26). 2. The solar-powered single and double-effect coupled lithium bromide refrigerator according to claim 1, characterized in that it has three different operating modes: In the first mode, the solar energy drives the single and double effect coupled lithium bromide refrigerator to operate in double effect: the hot water generated by the solar medium temperature collector (1) directly enters the high pressure generator (24); In the second mode, the single-effect operation of the single-effect coupled lithium bromide refrigerator driven by solar energy: the hot water produced by the solar medium-temperature heat collector (1) enters the hot water generator in the low-pressure generator (23); In the third mode, the gas boiler drives the double-effect coupled lithium bromide refrigerator for double-effect operation: the hot water generated by the gas boiler (3) enters the high-pressure generator (24). 3. The solar-driven single and double-effect coupled lithium bromide refrigerator according to claim 2, characterized in that the corresponding operating mode is automatically selected according to the outlet temperature of the solar medium-temperature heat collector (1), and the switch of the relevant water pump valve is controlled. 4. The solar-driven single and double-effect coupling type lithium bromide refrigerator according to claim 1 is characterized in that, the hot water produced by the solar medium temperature collector (1) is used as the main heat source, and the gas is used when the irradiation condition is not good. The boiler (3) serves as a supplement.