Combined cooling and heating power plant air conditioning system

Abstract

The utility model discloses a cold and heat combined supply type power plant air conditioning system which comprises an air-cooled heat pump type cold / hot water unit, a steam-water heat exchanger, a chilled water circulating pump, a hot water circulating pump, a chilled water distributor, a chilled water collector, a hot water distributor, a hot water collector, electric switch valves F1-F5, a chilled water pipeline and a hot water pipeline. One part of the air-cooled heat pump type cold / hot water units are connected with a chilled water distributor, a chilled water collector and a chilled water circulating pump through chilled water pipelines, and the other part of the air-cooled heat pump type cold / hot water units are connected with a hot water distributor, a hot water collector and a hot water circulating pump through hot water pipelines; the steam-water heat exchanger is connected to the air-cooled heat pump type cold / hot water unit in parallel; the electric switch valves F1-F5 are arranged on the water supply side of the air-cooled heat pump type cold / hot water unit and the water supply side of the steam-water heat exchanger respectively. The working mechanism of parallel cooling and heating of the air-conditioning system is realized, the initial investment and the operation cost of the air-conditioning system are reduced, and the comprehensive energy efficiency of the air-conditioning system is improved.

Description

Technical Field

[0001] This utility model relates to the field of air conditioning technology, and more specifically to a combined cooling and heating power plant air conditioning system. Background Technology

[0002] The power industry is a fundamental energy sector of the national economy, and thermal power generation remains the primary mode of power generation in my country, with ample room for future development. The safe, stable, and efficient operation of the air conditioning system is crucial for ensuring the proper temperature and humidity environment for critical equipment in power plants. Power plants have numerous equipment rooms, some of which generate significant heat and require year-round cooling; while the plant area also contains many office areas for personnel, whose temperature and humidity requirements differ from those of the equipment rooms.

[0003] Traditional two-pipe air conditioning systems, which combine chiller units and heat pump units, can only meet single cooling or heating requirements and are difficult to meet the air conditioning needs of buildings with both cooling and heating loads at the same time, thus having significant limitations in application. Utility Model Content

[0004] This utility model provides an energy-efficient, safe, and reliable combined cooling and heating power plant air conditioning system that simultaneously meets the needs of cooling and heating, which can solve at least one of the above-mentioned technical problems.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] A combined cooling and heating power plant air conditioning system includes an air-cooled heat pump type chiller / hot water unit, a steam-water heat exchanger, a chilled water circulating pump, a hot water circulating pump, a chilled water distributor, a chilled water collector, a hot water distributor and a hot water collector, and also includes electric on / off valves F1 to F5, as well as chilled water pipelines and hot water pipelines.

[0007] The air-cooled heat pump type chilled / hot water unit has multiple units, which are connected in parallel to the chilled water pipeline or the hot water pipeline. A portion of the air-cooled heat pump type chilled / hot water unit is connected to the chilled water distributor, the chilled water collector and the chilled water circulation pump via the chilled water pipeline. Another portion of the air-cooled heat pump type chilled / hot water unit is connected to the hot water distributor, the hot water collector and the hot water circulation pump via the hot water pipeline.

[0008] The steam-water heat exchanger is connected in parallel to the air-cooled heat pump type chiller / hot water unit for use as a backup heat source;

[0009] The electric switching valves F1 to F5 are respectively installed on the water supply side of the air-cooled heat pump chiller / hot water unit and the steam-water heat exchanger, and are used to switch the operating mode of the system.

[0010] Furthermore, both the chilled water pipeline and the hot water pipeline are arranged in a four-pipe configuration. The chilled water pipeline includes at least a chilled water supply header and a chilled water return header, and the hot water pipeline includes at least a hot water supply header and a hot water return header.

[0011] Furthermore, the chilled water dewatering unit and the chilled water collector are respectively located at the cooling user end. The chilled water dewatering unit is connected to the air-cooled heat pump type chilled / hot water unit via the chilled water supply header. The air-cooled heat pump type chilled / hot water unit is connected to the chilled water collector via the chilled water return header. There are multiple chilled water circulation pumps, each corresponding to one of the air-cooled heat pump type chilled / hot water units, and they are connected in parallel on the chilled water return header.

[0012] Furthermore, the hot water distributor and the hot water collector are respectively located at the heating user end. The hot water distributor is connected to the air-cooled heat pump type chiller / hot water unit via the hot water supply header. The air-cooled heat pump type chiller / hot water unit is connected to the hot water collector via the hot water return header. There are multiple hot water circulation pumps, each corresponding to one of the air-cooled heat pump type chiller / hot water units connected in parallel to the hot water supply header, and also connected in parallel to the hot water return header.

[0013] Furthermore, it also includes a fully automatic water filter, which has two sets, respectively installed on the chilled water return main pipe and the hot water return main pipe. The fully automatic water filter installed on the chilled water return main pipe is connected between the chilled water collector and the chilled water circulation pump, and the fully automatic water filter installed on the hot water return main pipe is connected between the hot water collector and the hot water circulation pump.

[0014] Furthermore, it also includes an automatic constant pressure water supply unit, which has two sets. One set is connected to the chilled water return main pipe and is connected between the fully automatic water filter and the chilled water collector. The other set is connected to the hot water return main pipe and is connected between the fully automatic water filter and the hot water collector.

[0015] Furthermore, it also includes a first temperature sensor and a second temperature sensor. The first temperature sensor is installed on the chilled water return main pipe of the chilled water collector to monitor the chilled water return temperature in real time. The second temperature sensor is installed on the hot water return main pipe of the hot water collector to monitor the hot water return temperature in real time.

[0016] Furthermore, the steam-water heat exchanger is used as a backup heat source when the outdoor temperature is too low or the air-cooled heat pump type chiller / hot water unit cannot provide normal heating. The heat source of the steam-water heat exchanger is the power plant steam heat source, which is connected through a steam pipeline. The condensate generated after heat exchange by the steam-water heat exchanger is discharged to the power plant's recycled water system through a condensate pipeline.

[0017] Furthermore, it includes four operating modes:

[0018] Operating Mode 1: Under the operating mode 1 condition, the air-cooled heat pump chiller / hot water unit only supplies cooling;

[0019] Operating Mode 2: Under the operating mode 2 condition, the air-cooled heat pump chiller / hot water unit only provides heating;

[0020] Operating Mode 3: Under the operating mode 3 condition, the air-cooled heat pump chiller / hot water unit provides both cooling and heating simultaneously;

[0021] Operating Mode 4: Under the operating mode described above, the steam-water heat exchanger provides heat independently.

[0022] Furthermore, in the first operating mode, the air-cooled heat pump chiller / hot water unit and the chilled water circulation pump are in operation, the electric switching valves F1, F2 and F4 are open, and the electric switching valves F3 and F5 are closed;

[0023] In the second operating mode, the air-cooled heat pump chiller / hot water unit connected in parallel with the hot water supply main pipe and the hot water circulation pump are in operation, the electric switch valves F3 and F4 are open, and the electric switch valves F1, F2 and F5 are closed.

[0024] In the third operating mode, the air-cooled heat pump chiller / hot water unit, the chilled water circulation pump and the hot water circulation pump are in operation, the electric switch valves F1 and F4 are open, the electric switch valve F5 is closed, and the electric switch valves F2 and F3 are open or closed.

[0025] In the fourth operating mode, the steam-water heat exchanger and the hot water circulation pump are running, the electric switch valve F5 is open, and the electric switch valves F1, F2, F3 and F4 are closed.

[0026] The beneficial effects of this utility model are reflected in:

[0027] 1. By utilizing air-cooled heat pump chiller / hot water unit with a four-pipe layout, the air conditioning system can achieve a simple and efficient parallel cooling and heating operation mechanism, reducing the initial investment and operating costs of the air conditioning system and improving the overall energy efficiency of the air conditioning system.

[0028] 2. When the outdoor temperature is too low or the air-cooled heat pump type chiller / hot water unit cannot provide normal heating, the steam-water heat exchanger is used as a backup heat source. The heat source of the steam-water heat exchanger is the power plant steam heat source. The condensate produced after heat exchange is discharged to the power plant recovery water system through the condensate pipeline to ensure the stable and reliable operation of the heating system.

[0029] 3. By using a four-pipe layout and multiple electrically controlled valves for switching, the system can freely switch between four operating modes, improving the flexibility and reliability of the air conditioning system. Attached Figure Description

[0030] The accompanying drawings, which are provided to further illustrate this application and form part of this application, illustrate exemplary embodiments of this application and are used to explain this application, but do not constitute an undue limitation of this application.

[0031] Figure 1 This is a schematic diagram of the overall structure of the air conditioning system according to an embodiment of the present utility model.

[0032] The components in the attached diagram are labeled as follows: 1. Air-cooled heat pump type chiller / hot water unit; 2. Steam-water heat exchanger; 3. Chilled water circulation pump; 4. Hot water circulation pump; 5. Automatic constant pressure water supply unit; 6. Fully automatic water filter; 7. Chilled water distributor; 8. Chilled water collector; 9. Hot water distributor; 10. Hot water collector; 11. First temperature sensor; 12. Second temperature sensor. Detailed Implementation

[0033] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present utility model, and not all of them. Unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present utility model.

[0034] It should be noted that if the embodiments of this utility model involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Furthermore, the meaning of "and / or" throughout the text includes three parallel solutions; for example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied. Additionally, "multiple" refers to two or more.

[0035] It should be noted that those skilled in the art will understand that all or part of the steps implemented in the embodiments of this utility model can be implemented entirely or partially by software, hardware, firmware, or any combination thereof. When implemented in hardware, it can be implemented entirely or partially by purchasing standard parts or modified parts. When implemented in software, it can be implemented entirely or partially in the form of a computer program product.

[0036] See Figure 1 This utility model provides a combined cooling and heating power plant air conditioning system, including an air-cooled heat pump type chiller / hot water unit 1, a steam-water heat exchanger 2, a chilled water circulation pump 3, a hot water circulation pump 4, a chilled water distributor 7, a chilled water collector 8, a hot water distributor 9, and a hot water collector 10, and also includes electric switching valves F1 to F5, as well as chilled water pipelines and hot water pipelines;

[0037] The air-cooled heat pump type chiller / hot water unit 1 has multiple units, which are respectively connected in parallel to the chilled water pipeline or the hot water pipeline. A portion of the air-cooled heat pump type chiller / hot water unit 1 is connected to the chilled water distributor 7, the chilled water collector 8 and the chilled water circulation pump 3 via the chilled water pipeline. Another portion of the air-cooled heat pump type chiller / hot water unit 1 is connected to the hot water distributor 9, the hot water collector 10 and the hot water circulation pump 4 via the hot water pipeline.

[0038] The steam-water heat exchanger 2 is connected in parallel to the air-cooled heat pump type chiller / hot water unit 1 for use as a backup heat source;

[0039] The electric switching valves F1 to F5 are respectively installed on the water supply side of the air-cooled heat pump type chiller / hot water unit 1 and the steam-water heat exchanger 2, and are used to switch the operating mode of the system.

[0040] See Figure 1 In this embodiment, both the chilled water pipeline and the hot water pipeline are arranged in a four-pipe configuration. The chilled water pipeline includes at least a chilled water supply header and a chilled water return header, and the hot water pipeline includes at least a hot water supply header and a hot water return header.

[0041] Four-pipe system refers to an air conditioning unit that is equipped with both cooling coils and heating coils. Each set of coils has one inlet and one outlet, for a total of four pipes, hence the name "four-pipe system." The two sets of water pipes are connected to cold water and hot water respectively, meaning that cooling and heating can be switched at any time of year, allowing some rooms to be heated while others are cooled.

[0042] See Figure 1In this embodiment, the chilled water dewatering unit 7 and the chilled water collector 8 are respectively located at the cooling user end. The chilled water dewatering unit 7 is connected to the air-cooled heat pump type chilled / hot water unit 1 via the chilled water supply header. The air-cooled heat pump type chilled / hot water unit 1 is connected to the chilled water collector 8 via the chilled water return header. There are multiple chilled water circulation pumps 3, each corresponding to one of the air-cooled heat pump type chilled / hot water units 1, and connected in parallel on the chilled water return header.

[0043] See Figure 1 In this embodiment, the hot water distributor 9 and the hot water collector 10 are respectively located at the heating user end. The hot water distributor 9 is connected to the air-cooled heat pump type chiller / hot water unit 1 via the hot water supply header. The air-cooled heat pump type chiller / hot water unit 1 is connected to the hot water collector 10 via the hot water return header. There are multiple hot water circulation pumps 4, each corresponding to one of the air-cooled heat pump type chiller / hot water units 1 connected in parallel to the hot water supply header, and connected in parallel to the hot water return header.

[0044] See Figure 1 In this embodiment, a fully automatic water filter 6 is also included. Two sets of the fully automatic water filter 6 are respectively installed on the chilled water return main pipe and the hot water return main pipe. The fully automatic water filter 6 installed on the chilled water return main pipe is connected between the chilled water collector 8 and the chilled water circulation pump 3. The fully automatic water filter 6 installed on the hot water return main pipe is connected between the hot water collector 10 and the hot water circulation pump 4. The fully automatic water filter 6 is used to filter the water, ensuring the water quality in the air conditioning system's supply and return water circulation.

[0045] See Figure 1 In this embodiment, an automatic constant pressure water supply unit 5 is also included. The automatic constant pressure water supply unit 5 has two sets. One set is connected to the chilled water return main pipe and is connected between the fully automatic water filter 6 and the chilled water collector 8. The other set is connected to the hot water return main pipe and is connected between the fully automatic water filter 6 and the hot water collector 10.

[0046] The automatic constant-pressure water supply unit 5 is connected to a domestic water source. It uses a constant-pressure device to regulate the volume expansion and contraction of the water system, ensuring the pressure setpoint remains constant. Water in a circulating system expands and contracts with temperature changes, while the total volume of water within the system remains essentially constant. This fluctuation affects the system pressure and may impact its normal operation. By using a constant-pressure device, such as the automatic constant-pressure water supply unit 5, the effects of temperature changes can be eliminated.

[0047] See Figure 1In this embodiment, a first temperature sensor 11 and a second temperature sensor 12 are also included. The first temperature sensor 11 is installed on the chilled water return main pipe of the chilled water collector 8 and is used to monitor the chilled water return temperature in real time. The second temperature sensor 12 is installed on the hot water return main pipe of the hot water collector 10 and is used to monitor the hot water return temperature in real time.

[0048] Based on the return water temperature monitored by the first temperature sensor 11 or the second temperature sensor 12, the cooling / heating / simultaneous cooling and heating operation modes of the air-cooled heat pump chiller / hot water unit 1 connected to the chilled water pipeline or hot water pipeline are switched to adjust the cooling and heating capacity of the air conditioning system.

[0049] See Figure 1 In this embodiment, the steam-water heat exchanger 2 serves as a backup heat source when the outdoor temperature is too low or the air-cooled heat pump chiller / hot water unit 1 cannot provide normal heating. The heat source for the steam-water heat exchanger 2 is power plant steam, connected via a steam pipeline. The condensate produced after heat exchange in the steam-water heat exchanger 2 is discharged to the power plant's recycled water system via a condensate pipeline. Utilizing power plant steam as an emergency backup heat source ensures stable and reliable operation of the heating system, making the heating operation mode more flexible.

[0050] See Figure 1 In this embodiment, four operating modes are included:

[0051] Operating Mode 1: Under the operating mode 1 condition, the air-cooled heat pump chiller / hot water unit 1 only supplies cooling;

[0052] Operating Mode 2: Under the operating mode 2 condition, the air-cooled heat pump chiller / hot water unit 1 only provides heating;

[0053] Operating Mode 3: Under the operating mode 3 condition, the air-cooled heat pump type chiller / hot water unit 1 provides both cooling and heating simultaneously;

[0054] Operating Mode 4: Under the operating mode described above, the steam-water heat exchanger 2 provides heat independently.

[0055] See Figure 1 In this embodiment, in the first operating mode, the air-cooled heat pump chiller / hot water unit 1 and the chilled water circulation pump 3 are in operation. The electric switching valves F1, F2 and F4 are open, and the electric switching valves F3 and F5 are closed. The chilled water return from the cooling user end returns to the chilled water collector 8, is treated by the fully automatic water filter 6, and then returns to the air-cooled heat pump chiller / hot water unit 1 for heat exchange under the action of the chilled water circulation pump 3. Finally, it is supplied as chilled water through the chilled water separator 7.

[0056] In the second operating mode, the air-cooled heat pump chiller / hot water unit 1 and the hot water circulation pump 4, which are connected in parallel with the hot water supply main pipe, are in operation. The electric switch valves F3 and F4 are open, and the electric switch valves F1, F2 and F5 are closed. Similarly, the hot water return from the heating user end returns to the hot water collector 10, is treated by the fully automatic water filter 6, and then returns to the air-cooled heat pump chiller / hot water unit 1 for heat exchange under the action of the hot water circulation pump 4. Finally, it is supplied as hot water through the hot water distributor 9.

[0057] In the third operating mode, the air-cooled heat pump chiller / hot water unit 1, the chilled water circulation pump 3, and the hot water circulation pump 4 are in operation. The electric switching valves F1 and F4 are open, the electric switching valve F5 is closed, and the electric switching valves F2 and F3 are either open or closed. The opening and closing of the electric switching valves F2 and F3 are determined based on the chilled water return temperature monitored by the first temperature sensor 11 and the hot water return temperature monitored by the second temperature sensor 12. When the electric switching valve F2 is open, the corresponding air-cooled heat pump chiller / hot water unit 1 provides cooling; when the electric switching valve F3 is open, the corresponding air-cooled heat pump chiller / hot water unit 1 provides heating.

[0058] In the fourth operating mode, the steam-water heat exchanger 2 and the hot water circulation pump 4 are running, the electric switch valve F5 is open, and the electric switch valves F1, F2, F3 and F4 are closed.

[0059] The opening and closing states of the electric switching valves F1 to F5 under the four operating modes are shown in Table 1 below:

[0060] Table 1. Opening and closing status of electric on / off valves F1 to F5 in four operating modes.

[0061] Operating Mode 1 Operating Mode 2 Operating Mode 3 Operating Mode 4 F1 open close open close F2 open close switch close F3 close switch Close / Open close F4 open open open close F5 close close close open

[0062] In summary, this utility model, based on the air conditioning load characteristics within a power plant, achieves a parallel cooling and heating working mechanism for the air conditioning system by employing a heat pump-type air conditioning unit combined with a four-pipe layout. This reduces redundant configurations while ensuring the safe operation of the air conditioning system, lowers the initial investment and operating costs of the air conditioning system, and improves the overall energy efficiency of the air conditioning system. It has broad application prospects in thermal power plants.

[0063] It should be understood that the examples and embodiments described herein are for illustrative purposes only and are not intended to limit the present invention. Those skilled in the art can make various modifications or changes based on them. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A combined cooling and heating power plant air conditioning system, characterized in that, It includes air-cooled heat pump type chiller / hot water unit (1), steam-water heat exchanger (2), chilled water circulation pump (3), hot water circulation pump (4), chilled water distributor (7), chilled water collector (8), hot water distributor (9) and hot water collector (10), as well as electric switch valves F1 to F5 and chilled water pipelines and hot water pipelines; The air-cooled heat pump type chilled / hot water unit (1) has multiple units, which are connected in parallel to the chilled water pipeline or the hot water pipeline. A portion of the air-cooled heat pump type chilled / hot water unit (1) is connected to the chilled water distributor (7), the chilled water collector (8) and the chilled water circulation pump (3) via the chilled water pipeline. Another portion of the air-cooled heat pump type chilled / hot water unit (1) is connected to the hot water distributor (9), the hot water collector (10) and the hot water circulation pump (4) via the hot water pipeline. The steam-water heat exchanger (2) is connected in parallel to the air-cooled heat pump type chiller / hot water unit (1) for use as a backup heat source; The electric switching valves F1 to F5 are respectively installed on the water supply side of the air-cooled heat pump type chiller / hot water unit (1) and the steam-water heat exchanger (2) to switch the operating mode of the system.

2. The combined cooling and heating power plant air conditioning system as described in claim 1, characterized in that, Both the chilled water pipeline and the hot water pipeline are arranged in a four-pipe configuration. The chilled water pipeline includes at least a chilled water supply header and a chilled water return header, and the hot water pipeline includes at least a hot water supply header and a hot water return header.

3. The combined cooling and heating power plant air conditioning system as described in claim 2, characterized in that, The chilled water dewatering unit (7) and the chilled water collector (8) are respectively located at the cooling user end. The chilled water dewatering unit (7) is connected to the air-cooled heat pump type chilled / hot water unit (1) via the chilled water supply header. The air-cooled heat pump type chilled / hot water unit (1) is connected to the chilled water collector (8) via the chilled water return header. There are multiple chilled water circulation pumps (3), each corresponding to one of the air-cooled heat pump type chilled / hot water units (1), and they are connected in parallel on the chilled water return header.

4. The combined cooling and heating power plant air conditioning system as described in claim 2, characterized in that, The hot water distributor (9) and the hot water collector (10) are respectively located at the heating user end. The hot water distributor (9) is connected to the air-cooled heat pump type chilled / hot water unit (1) via the hot water supply header. The air-cooled heat pump type chilled / hot water unit (1) is connected to the hot water collector (10) via the hot water return header. There are multiple hot water circulation pumps (4), which correspond one-to-one with the air-cooled heat pump type chilled / hot water unit (1) connected in parallel to the hot water supply header, and are connected in parallel to the hot water return header.

5. The combined cooling and heating power plant air conditioning system as described in claim 2, characterized in that, It also includes a fully automatic water filter (6), which has two sets, respectively installed on the chilled water return main pipe and the hot water return main pipe. The fully automatic water filter (6) installed on the chilled water return main pipe is connected between the chilled water collector (8) and the chilled water circulation pump (3), and the fully automatic water filter (6) installed on the hot water return main pipe is connected between the hot water collector (10) and the hot water circulation pump (4).

6. The combined cooling and heating power plant air conditioning system as described in claim 5, characterized in that, It also includes an automatic constant pressure water supply unit (5), which has two sets. One set is connected to the chilled water return main pipe and is connected between the fully automatic water filter (6) and the chilled water collector (8). The other set is connected to the hot water return main pipe and is connected between the fully automatic water filter (6) and the hot water collector (10).

7. The combined cooling and heating power plant air conditioning system as described in claim 2, characterized in that, It also includes a first temperature sensor (11) and a second temperature sensor (12). The first temperature sensor (11) is installed on the chilled water return main pipe of the chilled water collector (8) for real-time monitoring of the chilled water return temperature. The second temperature sensor (12) is installed on the hot water return main pipe of the hot water collector (10) for real-time monitoring of the hot water return temperature.

8. The combined cooling and heating power plant air conditioning system as described in claim 1, characterized in that, The steam-water heat exchanger (2) is used as a backup heat source when the outdoor temperature is too low or the air-cooled heat pump type chiller / hot water unit (1) cannot provide normal heating. The heat source of the steam-water heat exchanger (2) is the power plant steam heat source, which is connected through a steam pipeline. The condensate generated after the heat exchange of the steam-water heat exchanger (2) is discharged to the power plant's recycled water system through the condensate pipeline.

9. The combined cooling and heating power plant air conditioning system as described in claim 1, characterized in that, Includes four operating modes: Operating mode 1: Under the operating mode 1 condition, the air-cooled heat pump chiller / hot water unit (1) only supplies cooling; Operating mode 2: Under the operating mode 2 condition, the air-cooled heat pump type chiller / hot water unit (1) only provides heating; Operating mode 3: Under the operating mode 3 condition, the air-cooled heat pump type chiller / hot water unit (1) provides both cooling and heating simultaneously; Operating mode four: Under the operating mode four conditions, the steam-water heat exchanger (2) provides heat independently.

10. The combined cooling and heating power plant air conditioning system as described in claim 9, characterized in that, In the first operating mode, the air-cooled heat pump chiller / hot water unit (1) and the chilled water circulation pump (3) are in operation, the electric switch valves F1, F2 and F4 are open, and the electric switch valves F3 and F5 are closed. In the second operating mode, the air-cooled heat pump type chiller / hot water unit (1) and the hot water circulation pump (4) connected in parallel with the hot water supply main pipe are in operation, the electric switch valves F3 and F4 are open, and the electric switch valves F1, F2 and F5 are closed. In the third operating mode, the air-cooled heat pump chiller / hot water unit (1), the chilled water circulation pump (3) and the hot water circulation pump (4) are running, the electric switch valves F1 and F4 are open, the electric switch valve F5 is closed, and the electric switch valves F2 and F3 are open or closed. In the fourth operating mode, the steam-water heat exchanger (2) and the hot water circulation pump (4) are running, the electric switch valve F5 is open, and the electric switch valves F1, F2, F3 and F4 are closed.

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