JP7614383B2 - Heating and Cooling Systems - Google Patents

Description

This disclosure relates to heating and cooling systems.

Heating and cooling systems equipped with solar water heaters are known. For example, in the system of Patent Document 1, hot water heated by the solar water heater is used during heating operation, and cooling water cooled by a cooling tower is used during cooling operation.

JP 2009-236441 A

In Patent Document 1, when the air conditioning system is in cooling operation, hot water at 70 to 95°C is supplied from the hot water tank to the absorption chiller. The temperature of the hot water supplied to the absorption chiller is detected by a temperature sensor. The cooling tower operates only when the hot water temperature detected by the temperature sensor is higher than 70°C. In other words, the cooling tower operates only during the day when the air conditioning system is in cooling operation. The cooling tower does not operate at night, so the cooling water cannot be cooled sufficiently. As a result, the efficiency of cooling operation is low.

Therefore, the present disclosure provides a heating and cooling system with highly efficient cooling operation.

The air conditioning system of the present disclosure includes a cooling tower that cools heat source water, a plurality of water-source heat pump units each performing a cooling operation for cooling a space to be air-conditioned or a heating operation for heating the space to be air-conditioned, a heat source water pump for supplying heat source water from a heat source water tank to the plurality of water-source heat pump units, a first motor-operated valve disposed between the heat source water outlets of the plurality of water-source heat pump units and the heat source water inlet of the cooling tower, a second motor-operated valve disposed between the heat source water outlets of the plurality of water-source heat pump units and the heat source water inlet of the solar water heater, and a third motor-operated valve disposed between the heat source water outlets of the plurality of water-source heat pump units and the inlet of the heat source water tank. The heat source water outlet of the cooling tower is connected to the inlet of the heat source water tank. The heat source water outlet of the solar water heater is connected to the inlet of the heat source water tank. The heating and cooling system of the present disclosure includes a control device that controls a first motor-operated valve, a second motor-operated valve, and a third motor-operated valve.

The heating and cooling system disclosed herein can perform cooling operation with high efficiency.

FIG. 1 is a diagram showing the configuration of a heating and cooling system of a first reference example. 1 is a diagram showing the configuration of a heating and cooling system according to a first embodiment. 1 is a diagram showing the configuration of a water heat source heat pump unit 1 according to a first embodiment. 11 is a diagram showing the states of a first motor-operated valve V1, a second motor-operated valve V2, and a third motor-operated valve V3, and the flow of heat-source water. FIG. 4 is a diagram for explaining the relationship between the operation of the water-source heat pump unit 1 and the temperature of the heat source water. FIG. 11 is a diagram showing the flow of heat source water when the amount of solar radiation in winter is less than the reference amount of solar radiation. FIG. 11 is a diagram showing the flow of heat source water when the amount of solar radiation in winter is equal to or greater than the reference amount of solar radiation. FIG. 13 is a diagram showing the flow of heat source water in summer and intermediate seasons. 4 is a flowchart showing a control procedure of the heating and cooling system in winter in the first embodiment. 4 is a flowchart showing a control procedure of the heating and cooling system during the day in summer and intermediate seasons in the first embodiment. 4 is a flowchart showing a control procedure of the heating and cooling system during nighttime in summer and intermediate seasons in the first embodiment. FIG. 13 is a diagram showing the configuration of a heating and cooling system of a reference example 2. FIG. 11 is a diagram showing the configuration of a heating and cooling system according to a second embodiment. FIG. 11 is a diagram showing the configuration of a water heat source heat pump unit 1 according to a second embodiment.

Hereinafter, an embodiment will be described with reference to the drawings.
Embodiment 1.
FIG. 1 is a diagram showing the configuration of a cooling and heating system according to a first embodiment.

The heating and cooling system of Reference Example 1 comprises an auxiliary boiler 7 for heating heat source water, an expansion tank 3, a cooling tower 2 for cooling the heat source water, electric valves 5 and 6, a pressure regulating valve 4, and multiple water source heat pump units 1.

In summer and intermediate seasons, the water-source heat pump units 1 only perform cooling operation. In this case, the temperature of the heat source water rises, so the heating and cooling system operates the cooling tower 2 to suppress the rise in the temperature of the heat source water.

In winter, there is a mixture of water-source heat pump units 1 performing cooling operation and water-source heat pump units 1 performing heating operation. When the heating heat load is greater than the cooling heat load, the temperature of the heat source water drops, so the heating and cooling system uses the auxiliary boiler 7 to suppress the drop in the temperature of the heat source water. When the cooling heat load is greater than the heating heat load, the temperature of the heat source water rises, so the heating and cooling system operates the cooling tower 2 to suppress the rise in the temperature of the heat source water.

The cooling and heating system of Reference Example 1 has the following problems.
In winter, when the heating heat load is larger than the cooling heat load, it is necessary to operate the auxiliary boiler 7. At this time, the heat source water flows into the cooling tower 2, so that the heat source water is radiated by the cooling tower 2.

Cooling tower 2 only operates during daytime air conditioning operation, so it remains stopped at night when the wet-bulb temperature of the outside air is low, improving the cooling capacity of cooling tower 2.

FIG. 2 is a diagram showing the configuration of the cooling and heating system according to the first embodiment.
This heating and cooling system includes a plurality of water-source heat pump units 1, a heat-source water pump 8, a heat-source water tank 9, a cooling tower 2, a solar water heater 10, a pyranometer 11, a first motor-operated valve V1, a second motor-operated valve V2, a third motor-operated valve V3, and a pressure regulating valve 4.

The heat source water tank 9 is installed on the lowest floor. The cooling tower 2, solar water heater 10, and pyranometer 11 are installed on the roof.

The water-source heat pump unit 1 performs cooling operation to cool the space to be air-conditioned, or heating operation to heat the space. When the water-source heat pump unit 1 performs cooling operation, the heat source water is heated by the water-source heat pump unit 1. When the water-source heat pump unit 1 performs heating operation, the heat source water is cooled by the water-source heat pump unit 1.

The heat source water pump 8 is arranged in the heat source water supply pipe 61. The heat source water pump 8 supplies the heat source water stored in the heat source water tank 9 to the water source heat pump unit 1.

The heat source water tank 9 stores heat source water. The outlet of the heat source water tank 9 is connected to a heat source water supply pipe 61. The inlet of the heat source water tank 9 is connected to a heat source water return pipe 62. By installing the heat source water tank 9, the capacity of the cooling tower 2 can be reduced.

The cooling tower 2 is equipped with a fan that supplies outside air to the inside. The cooling tower 2 cools the heat source water by bringing the heat source water into contact with the outside air. The operation of the fan is controlled according to commands from the control device 12.

The solar water heater 10 generates hot water using solar heat. The solar water heater 10 heats the water flowing out of the water heat source heat pump unit 1. In this embodiment, the solar water heater 10 is used instead of the auxiliary boiler 7, thereby achieving energy savings.

The actinometer 11 is positioned near the solar hot water heater 10. The actinometer 11 measures the amount of solar radiation.

The first motor-operated valve V1 is disposed between the heat source water outlet of the multiple water-source heat pump units 1 and the heat source water inlet of the cooling tower 2. The heat source water outlet of the cooling tower 2 is connected to the inlet of the heat source water tank 9.

The second motor-operated valve V2 is disposed between the heat source water outlet of the multiple water-source heat pump units 1 and the heat source water inlet of the solar water heater 10. The heat source water outlet of the solar water heater 10 is connected to the inlet of the heat source water tank 9.

The third electric valve V3 is arranged between the heat source water outlets of the multiple water source heat pump units 1 and the heat source water inlet of the heat source water tank 9.

The heat source water tank 9 and the inlet of the water heat source heat pump unit 1 are connected through a heat source water supply pipe 61, a branch pipe 61a, and a branch pipe 61b. The outlet of the water heat source heat pump unit 1 and the branch point N1 are connected through a branch pipe 62b, a branch pipe 62a, and a heat source water return pipe 62.

Branch point N1 and connection point N2 are connected by branch pipe 63. A second motor-operated valve V2 and a solar water heater 10 are arranged in branch pipe 63. Branch point N1 and connection point N3 are connected by branch pipe 64. A third motor-operated valve V3 is arranged in branch pipe 64.

The heat source water return pipe 62 is connected to the heat source water tank 9 via a branch point N1, a connection point N2, and a connection point N3. A first motor-operated valve V1 and a cooling tower 2 are arranged between the branch point N1 and the connection point N2.

The branch point N4 of the heat source water supply pipe 61 and the branch point N5 of the heat source water return pipe 62 are connected by a bypass pipe 65. A pressure regulating valve 4 is disposed in the bypass pipe 65. By controlling the opening degree of the pressure regulating valve 4, the amount of heat source water flowing through the bypass pipe 65 is adjusted.

The control device 12 controls the first electric valve V1, the second electric valve V2, and the third electric valve V3.

FIG. 3 is a diagram showing the configuration of the water-source heat pump unit 1 according to the first embodiment.
The water-source heat pump unit 1 comprises a compressor 40, an intake side piping 41, a discharge side piping 42, an air-conditioning heat exchanger (coil) 50, an expansion valve (capillary tube) 51, a heat-source water-side heat exchanger 52, an air supply fan 55, and a filter 57.

The compressor 40 is connected to a suction side pipe 41 through which the heat medium is fed into the compressor 40, and a discharge side pipe 42 through which the heat medium is discharged from the compressor 40. The compressor 40 is configured to have a variable frequency by inverter control.

The suction side pipe 41 and the discharge side pipe 42 are connected to the first end side 44a and the second end side 44b of the heat medium circulation path 44 via a four-way valve 43. The four-way valve 43 switches the heat medium circulation path between the cooling operation state and the heating operation state.

An alternative fluorocarbon refrigerant such as HFC flows as a heat medium between the air conditioning heat exchanger 50, the expansion valve 51, the heat source water side heat exchanger 52 and the compressor 40 to form a refrigeration cycle.

The supply air fan 55 supplies the supply air SA, which has been heat exchanged with a heat medium in the air conditioning heat exchanger 50 and brought to the desired temperature, to the space to be air-conditioned.

When the supply air fan 55 is operated, the return air RA drawn into the water-source heat pump unit 1 from within each air-conditioned space is mixed with the outside air OA supplied to the ceiling space of each air-conditioned space by an exhaust fan (not shown), and then the mixture is brought to the desired temperature in the air-conditioning heat exchanger 50 and supplied to each air-conditioned space as supply air SA.

The heat source water is circulated and supplied to the heat source water side heat exchanger 52 by connecting a branch pipe 61b leading to a branch pipe 61a of the heat source water supply pipe 61 and a branch pipe 62b leading to a branch pipe 62a of the heat source water return pipe 62. The heat medium circulation path 44 passes through the heat source water side heat exchanger 52. More specifically, the heat medium circulation path 44 is provided as the inner pipe of a meandering double pipe, and the heat medium moving in the heat medium circulation path 44 is heated or cooled by thermal contact with the heat source water via the heat transfer surface when passing through the heat source water side heat exchanger 52.

The operating state of the water source heat pump unit 1 can be appropriately switched between cooling operation, fan operation or heating operation.

When performing cooling operation, the four-way valve 43 is switched to connect the suction side pipe 41 to the second end 44b of the heat medium circulation path 44, and the discharge side pipe 42 to the first end 44a of the heat medium circulation path 44. As a result, the heat medium supplied from the compressor 40 through the discharge side pipe 42 passes through the heat source water side heat exchanger 52, the expansion valve 51, and the air conditioning heat exchanger 50 in that order in the heat medium circulation path 44, and is returned to the compressor 40 again from the suction side pipe 41. As a result, the high-pressure gas heat medium supplied from the compressor 40 through the discharge side pipe 42 is converted into a high-pressure liquid heat medium by dissipating heat to the heat source water in the heat source water side heat exchanger 52, and is depressurized by the expansion valve 51. When the depressurized liquid heat medium evaporates in the air conditioning heat exchanger 50, it can cool the air to be conditioned, and the low-pressure gas heat medium that leaves the air conditioning heat exchanger 50 is returned to the compressor 40.

By making the air conditioning heat exchanger 50 function as an evaporator, the air to be conditioned (return air RA and outdoor air OA) that has been passed through the air conditioning heat exchanger 50 by operating the supply air fan 55 is cooled and supplied to each air conditioned space as supply air SA.

When performing heating operation, the four-way valve 43 is switched to connect the suction side pipe 41 to the first end 44a of the heat medium circulation path 44, and the discharge side pipe 42 to the second end 44b of the heat medium circulation path 44. As a result, the heat medium supplied from the compressor 40 through the discharge side pipe 42 passes through the air conditioning heat exchanger 50, the expansion valve 51, and the heat source water side heat exchanger 52 in that order in the heat medium circulation path 44, and is returned to the compressor 40 again from the suction side pipe 41. As a result, the high-pressure gas heat medium supplied from the compressor 40 through the discharge side pipe 42 can heat the air to be conditioned when condensed in the air conditioning heat exchanger 50, and the high-pressure liquid heat medium that leaves the air conditioning heat exchanger 50 is decompressed by the expansion valve 51, absorbs heat from the heat source water in the heat source water side heat exchanger 52, becomes a low-pressure gas heat medium, and is returned to the compressor 40.

By making the air conditioning heat exchanger 50 function as a condenser, the air to be conditioned (return air RA and outdoor air OA) that has been passed through the air conditioning heat exchanger 50 by operating the supply air fan 55 is heated and supplied to each air conditioned space as supply air SA.

When performing the air blowing operation, the operation of the compressor 40 is stopped, and the circulation of the heat medium in the heat medium circulation path 44 is stopped. In this way, the air to be conditioned (return air RA and outdoor air OA) that has been passed through the air-conditioning heat exchanger 50 by the operation of the supply air fan 55 is supplied to the space to be conditioned as supply air SA without heat exchange, thereby performing the ventilation operation.

Figure 4 is a diagram showing the states of the first motor-operated valve V1, the second motor-operated valve V2, and the third motor-operated valve V3, and the flow of heat source water.

When the first electric valve V1 is open, the second electric valve V2 is closed, and the third electric valve V3 is closed, the heat source water flowing out of the water source heat pump unit 1 flows into the cooling tower 2 and then returns to the heat source water tank 9.

When the first electric valve V1 is closed, the second electric valve V2 is open, and the third electric valve V3 is closed, the heat source water flowing out of the water source heat pump unit 1 flows into the solar water heater 10 and then returns to the heat source water tank 9.

When the first electric valve V1 is closed, the second electric valve V2 is closed, and the third electric valve V3 is open, the heat source water flowing out of the water-source heat pump unit 1 passes through (i.e., does not flow through any heat-absorbing or heat-releasing equipment) and returns to the heat source water tank 9.

In the following description, it is assumed that the periods of the year corresponding to winter, summer, and intermediate seasons are determined in advance. For example, winter can be December to March, summer can be June to September, and intermediate seasons can be April to May and October to November. It is assumed that the times of the day corresponding to daytime and nighttime are determined in advance. For example, nighttime can be 8 p.m. to 6 a.m., and daytime can be 6 a.m. to 8 p.m.

In winter, the water source heat pump unit 1 operates in heating or cooling mode. Therefore, among the multiple water source heat pump units 1, some operate in cooling mode and some operate in heating mode. In summer and intermediate seasons, the water source heat pump unit 1 operates only in cooling mode.

Figure 5 is a diagram illustrating the relationship between the operation of the water source heat pump unit 1 and the temperature of the heat source water.

The temperature of the heat source water at which the water source heat pump unit 1 can operate in heating mode is 5°C or higher and 45°C or lower. The temperature of the heat source water at which the water source heat pump unit 1 can operate in cooling mode is 7°C or higher and 45°C or lower.

Figure 6 shows the flow of heat source water when the amount of solar radiation in winter is less than the standard amount of solar radiation.

When the temperature Tt of the heat source water in the heat source water tank 9 is below the lower limit temperature Ttl (20°C), the heat source water flowing out of the water source heat pump unit 1 passes through directly.

When the temperature Tt of the heat source water in the heat source water tank 9 exceeds the upper limit temperature Tth (30°C), the heat source water flowing out of the water source heat pump unit 1 flows into the cooling tower 2.

When the temperature Tt of the heat source water in the heat source water tank 9 is equal to or higher than the lower limit temperature Ttl (20°C) and equal to or lower than the upper limit temperature Tth (30°C), the flow of the heat source water flowing out of the water heat source heat pump unit 1 does not change. In other words, if the heat source water is flowing into the cooling tower 2, it continues to flow into the cooling tower 2, and if the heat source water is passing through, it continues to pass through.

Figure 7 shows the flow of heat source water when the amount of solar radiation in winter is greater than or equal to the standard amount of solar radiation.

In the initial state, when the heat source water flowing out of the water source heat pump unit 1 passes through directly, it operates as follows.

When the temperature Tt of the heat source water in the heat source water tank 9 is below the lower limit temperature Ttl (20°C), the heat source water flowing out from the water source heat pump unit 1 flows into the solar water heater 10. When the temperature Tt of the heat source water in the heat source water tank 9 exceeds the upper limit temperature Tth (30°C), the heat source water flowing out from the water source heat pump unit 1 flows into the cooling tower 2. When the temperature Tt of the heat source water in the heat source water tank 9 is equal to or higher than the lower limit temperature Ttl (20°C) and equal to or lower than the upper limit temperature Tth (30°C), the heat source water flowing out from the water source heat pump unit 1 continues to pass through.

When the temperature Tt of the heat source water in the heat source water tank 9 is below the lower limit temperature Ttl (20°C), the heat source water flowing out of the water source heat pump unit 1 flows into the solar water heater 10.

When the temperature Tt of the heat source water in the heat source water tank 9 exceeds the upper limit temperature Tth (30°C), the heat source water flowing out of the water source heat pump unit 1 flows into the cooling tower 2.

When the temperature Tt of the heat source water in the heat source water tank 9 is equal to or higher than the lower limit temperature Ttl (20°C) and equal to or lower than the upper limit temperature Tth (30°C), the flow of the heat source water flowing out of the water heat source heat pump unit 1 does not change. In other words, if the heat source water is flowing to the cooling tower 2, it continues to flow to the cooling tower 2, and if the heat source water is flowing to the solar water heater 10, it continues to flow to the solar water heater 10.

In Figures 6 and 7, the lower limit temperature Ttl is set to 20°C and the upper limit temperature Tth is set to 30°C because, within this range, the water source heat pump unit 1 is capable of cooling operation and heating operation, and multiple water source heat pump units 1 can be operated efficiently.

FIG. 8 is a diagram showing the flow of heat source water in summer and intermediate seasons.
When the temperature Tt of the heat source water in the heat source water tank 9 exceeds the first threshold temperature (the lower limit of the cooling water temperature of the water source heat pump unit (7°C)), the heat source water flowing out of the water source heat pump unit 1 flows into the cooling tower 2.

When the temperature of the heat source water in the heat source water tank 9 exceeds the first threshold temperature during the night in summer and the intermediate season, the control device 12 opens the first motor valve V1 and closes the second motor valve V2 and the third motor valve V3. This causes the heat source water to flow into the cooling tower 2, so that the heat source water can be cooled by the cooling tower 2. Therefore, by operating the cooling tower 2 and the heat source water pump 8 during the night when the wet bulb temperature of the outside air is low, the temperature of the heat source water in the heat source water tank 9 can be lowered, thereby improving the efficiency of the cooling operation of the water source heat pump unit 1 during the day.

During the nighttime hours of summer and intermediate seasons, the control device 12 stops the heat source water pump 8 and stops the fan of the cooling tower 2 when the temperature of the heat source water in the heat source water tank 9 is below a first threshold temperature.

In winter, when the amount of solar radiation is less than a first reference value (reference solar radiation) and the temperature of the heat source water in the heat source water tank 9 is less than a second threshold temperature (lower limit temperature Ttl (20°C)), the control device 12 opens the third motor valve V3 and closes the first motor valve V1 and the second motor valve V2. As a result, the heat source water returns to the heat source water tank 9 without flowing to the cooling tower 2 or the solar water heater 10. This prevents the heat source water from being heated or cooled. Therefore, on days with a large heating heat load, it is possible to prevent the heat source water from radiating heat in the cooling tower 2.

In winter, when the amount of solar radiation is less than a first reference value (reference amount of solar radiation) and the temperature of the heat source water in the heat source water tank 9 exceeds a third threshold temperature (upper limit temperature Tth (30°C)), the control device 12 opens the first motor-operated valve V1 and closes the second motor-operated valve V2 and the third motor-operated valve V3. This allows the heat source water to flow into the cooling tower 2, so that the heat source water can be cooled by the cooling tower 2.

In winter, when the amount of solar radiation is less than a first reference value (reference amount of solar radiation) and the temperature of the heat source water in the heat source water tank 9 is equal to or higher than a second threshold temperature (lower limit temperature Ttl (20°C)) and equal to or lower than a third threshold temperature (upper limit temperature Tth (30°C)), the control device 12 maintains the states of the first motor-operated valve V1, the second motor-operated valve V2, and the third motor-operated valve V3. This makes it possible to maintain a state in which the heat source water is heated, cooled, or neither heated nor cooled.

In winter, when the amount of solar radiation is equal to or greater than the first reference (reference amount of solar radiation) value and the temperature of the heat source water in the heat source water tank 9 is less than the second threshold temperature (lower limit temperature Ttl (20°C)), the control device 12 opens the second motor valve V2 and closes the first motor valve V1 and the third motor valve V3. As a result, the heat source water flows into the solar water heater 10, so that the heat source water can be heated by the solar water heater 10. Therefore, on sunny days in winter, the temperature of the heat source water in the heat source water tank 9 can be raised (heat storage) by using the solar water heater 10 in combination with the heat source water tank 9, and it is possible to prepare for subsequent days when the heating load increases due to cloudy or rainy weather.

In winter, when the amount of solar radiation is equal to or greater than a first reference value (reference amount of solar radiation) and the temperature of the heat source water in the heat source water tank 9 exceeds a third threshold temperature (upper limit temperature Tth (30°C)), the control device 12 opens the first motor-operated valve V1 and closes the second motor-operated valve V2 and the third motor-operated valve V3. This allows the heat source water to flow into the cooling tower 2, so that the heat source water can be cooled by the cooling tower 2.

In winter, when the amount of solar radiation is equal to or greater than a first reference value (reference amount of solar radiation) and the temperature of the heat source water in the heat source water tank 9 is equal to or greater than a second threshold temperature (lower limit temperature Ttl (20°C)) and equal to or less than a third threshold temperature (upper limit temperature Tth (30°C)), the control device 12 maintains the states of the first motor-operated valve V1, the second motor-operated valve V2, and the third motor-operated valve V3. This makes it possible to maintain a state in which the heat source water is heated, cooled, or neither heated nor cooled.

During daytime hours in summer and intermediate seasons, when the temperature of the heat source water in the heat source water tank 9 exceeds a first threshold temperature, the control device 12 opens the first motor-operated valve V1 and closes the second motor-operated valve V2 and the third motor-operated valve V3. This allows the heat source water to flow into the cooling tower 2, so that the heat source water can be cooled by the cooling tower 2.

During daytime hours in summer and intermediate seasons, when the temperature of the heat source water in the heat source water tank 9 is equal to or lower than the first threshold temperature (7°C), the control device 12 opens the third motor valve V3 and closes the first motor valve V1 and the second motor valve V2. As a result, the heat source water returns to the heat source water tank 9 without flowing to the cooling tower 2 or the solar water heater 10. This prevents the heat source water from being heated or cooled. It also prevents the heat source water from falling below the lower limit of the cooling water temperature (7°C).

Figure 9 is a flowchart showing the control procedure for the heating and cooling system in winter in embodiment 1.

In step S101, the control device 12 operates the heat source water pump 8 and opens only the third motor-operated valve V3. This allows the heat source water flowing out of the water-source heat pump unit 1 to pass through.

In step S102, each of the multiple water source heat pump units 1 is optionally in heating operation, cooling operation, or stopped.

In step S103, when the amount of solar radiation Sq detected by the actinometer 11 is less than the reference amount of solar radiation Sq0, the process proceeds to step S104, and when the amount of solar radiation Sq detected by the actinometer 11 is equal to or greater than the reference amount of solar radiation Sq0, the process proceeds to step S107.

In step S104, if the temperature Tt of the heat source water in the heat source water tank 9 is less than the lower limit temperature Ttl (20°C), the process proceeds to step S105, and if the temperature Tt of the heat source water in the heat source water tank 9 exceeds the upper limit temperature Tth (30°C), the process proceeds to step S106.

In step S105, the control device 12 opens only the third motor-operated valve V3. This allows the heat source water flowing out of the water-source heat pump unit 1 to pass through. The process then returns to step S103.

In step S106, the control device 12 opens only the first motor-operated valve V1. This causes the heat source water flowing out of the water-source heat pump unit 1 to flow into the cooling tower 2. At this time, the control device 12 operates the fan of the cooling tower 2. The process then returns to step S103.

In step S104, when the temperature Tt of the heat source water in the heat source water tank 9 is equal to or higher than the lower limit temperature Ttl (20°C) and equal to or lower than the upper limit temperature Tth (30°C), the process returns to step S103. As a result, the states of the first motor-operated valve V1, the second motor-operated valve V2, and the third motor-operated valve V3 do not change. Therefore, the destination of the heat source water flowing out of the water-source heat pump unit 1 does not change.

In step S107, if the temperature Tt of the heat source water in the heat source water tank 9 is less than the lower limit temperature Ttl (20°C), the process proceeds to step S108, and if the temperature Tt of the heat source water in the heat source water tank 9 exceeds the upper limit temperature Tth (30°C), the process proceeds to step S109.

In step S108, the control device 12 opens only the second motor-operated valve V2. This causes the heat source water flowing out of the water-source heat pump unit 1 to flow to the solar water heater 10. The process then returns to step S103.

In step S109, the control device 12 opens only the first motor-operated valve V1. This causes the heat source water flowing out of the water-source heat pump unit 1 to flow into the cooling tower 2. At this time, the control device 12 operates the fan of the cooling tower 2. The process then returns to step S103.

In step S107, when the temperature Tt of the heat source water in the heat source water tank 9 is equal to or higher than the lower limit temperature Ttl (20°C) and equal to or lower than the upper limit temperature Tth (30°C), the process returns to step S103. As a result, the states of the first motor-operated valve V1, the second motor-operated valve V2, and the third motor-operated valve V3 do not change. Therefore, the destination of the heat source water flowing out of the water-source heat pump unit 1 does not change.

Figure 10 is a flowchart showing the control procedure for the heating and cooling system during the day in summer and intermediate seasons in embodiment 1.

In step S201, the control device 12 operates the heat source water pump 8. The control device 12 operates the fan of the cooling tower 2. The control device 12 opens only the first motor-operated valve V1. As a result, the heat source water flowing out from the water-source heat pump unit 1 flows into the cooling tower 2.

In step S202, each of the multiple water source heat pump units 1 is optionally operated in cooling mode or stopped.

In step S203, if the temperature Tt of the heat source water in the heat source water tank 9 is equal to or lower than the first threshold temperature (7°C), the process proceeds to step S204, and if the temperature Tt of the heat source water in the heat source water tank 9 exceeds the first threshold temperature (7°C), the process proceeds to step S205.

In step S204, the control device 12 opens only the third motor-operated valve V3. This allows the heat source water flowing out of the water-source heat pump unit 1 to pass through. The process then returns to step S203.

In step S205, the control device 12 opens only the first motor-operated valve V1. This causes the heat source water flowing out of the water-source heat pump unit 1 to flow into the cooling tower 2. The process then returns to step S203.

Figure 11 is a flowchart showing the control procedure for the heating and cooling system during summer and intermediate season nights in embodiment 1.

In step S301, the control device 12 operates the heat source water pump 8. The control device 12 opens only the first motor-operated valve V1. This causes the heat source water flowing out of the water-source heat pump unit 1 to flow into the cooling tower 2.

In step S302, the control device 12 operates the fan of the cooling tower 2.
In step S303, if the temperature Tt of the heat source water in the heat source water tank 9 is below the first threshold temperature (7°C), the processing proceeds to step S304, and if the temperature Tt of the heat source water in the heat source water tank 9 exceeds the first threshold temperature (7°C), the processing proceeds to step S305.

In step S304, the control device 12 stops the heat source water pump 8. The control device 12 stops the fan of the cooling tower 2. Then, the processing ends.

In step S305, the control device 12 opens only the first motor-operated valve V1. This causes the heat source water flowing out of the water-source heat pump unit 1 to flow into the cooling tower 2. The process then returns to step S303.

Embodiment 2.
FIG. 12 is a diagram showing the configuration of a cooling and heating system according to the second embodiment.

The difference between the heating and cooling system of Reference Example 2 and the heating and cooling system of Reference Example 1 is the configuration of the water source heat pump unit 1.

The heating and cooling system of Reference Example 2 has the following problems, similar to those of the heating and cooling system of Reference Example 1.

In winter, when the heating heat load is greater than the cooling heat load, the auxiliary boiler 7 must be operated. At this time, the heat source water flows into the cooling tower 2, and the heat of the heat source water is released by the cooling tower 2.

Cooling tower 2 only operates during daytime air conditioning operation, so it remains stopped at night when the wet-bulb temperature of the outside air is low, improving the cooling capacity of cooling tower 2.

FIG. 13 is a diagram showing the configuration of a cooling and heating system according to the second embodiment.
The heating and cooling system of the second embodiment differs from the heating and cooling system of the first embodiment in the configuration of the water-source heat pump unit 1.

The heat source water tank 9 and the inlet of the water heat source heat pump unit 1 are connected via a heat source water supply pipe 61 and a branch pipe 61a. The outlet of the water heat source heat pump unit 1 and the branch point N1 are connected via a branch pipe 62a and a heat source water return pipe 62.

The control device 12 controls the first electric valve V1, the second electric valve V2, and the third electric valve V3, as in embodiment 1.

FIG. 14 is a diagram showing the configuration of a water-source heat pump unit 1 according to the second embodiment.
The water-source heat pump unit 1 includes a heat source unit 20, a diversion controller 21, and a plurality of indoor units 22. The heat source unit 20, the diversion controller 21, and the plurality of indoor units 22 configure a water-cooled multi-air conditioner for a building.

The heat source unit 20 absorbs or releases heat by using the heat source water flowing through the branch pipe 61a.
The flow division controller 21 forms a flow path for supplying gaseous refrigerant to the indoor unit 22 performing heating and liquid refrigerant to the indoor unit 22 performing cooling. One or more indoor units 22 are installed for each room. The indoor units 22 supply cold air or warm air to the room in which they are installed. The operation mode and room temperature setting of the indoor units 22 can be set individually.

The heat source unit 20 includes a compressor 91 and a flow path switching device 92 through which the refrigerant flows, and a water-cooled condenser 94 through which the refrigerant and heat source water flow. The water-cooled condenser 94 is of a double-pipe type, with the heat source water flowing on the inside and the refrigerant flowing on the outside.

The indoor unit 22 includes an indoor heat exchanger 93 through which a refrigerant flows, and a blower 96 .
The operation of the water-source heat pump unit 1 when the operation mode is cooling will be described below. In Fig. 14, the flow direction of the refrigerant during heating is indicated by solid arrows.

The flow path of the flow path switching device 92 is switched so that the refrigerant discharged from the compressor 91 flows into the indoor heat exchanger 93. The low-temperature, low-pressure refrigerant is compressed by the compressor 91, and a high-temperature, high-pressure gas refrigerant is discharged from the compressor 91. The gas refrigerant discharged from the compressor 91 flows into the indoor heat exchanger 93 via the flow path switching device 92. The refrigerant that flows into the indoor heat exchanger 93 condenses by exchanging heat with the air in the indoor heat exchanger 93, becoming a low-temperature, high-pressure liquid refrigerant that flows out of the indoor heat exchanger 93. The liquid refrigerant that flows out of the indoor heat exchanger 93 is turned into a low-temperature, low-pressure liquid refrigerant by the water-cooled condenser 94. The low-temperature, low-pressure liquid refrigerant flows into the compressor 91 via the flow path switching device 92.

The heat source water flowing out of the water-cooled condenser 94 flows into the heat source water return pipe 62 via the branch pipe 62 a.
The operation of the water-source heat pump unit 1 when the operation mode is heating will be described below. In Fig. 14, the flow direction of the refrigerant during cooling is indicated by dashed arrows.

When low-temperature, low-pressure refrigerant is compressed by the compressor 91, high-temperature, high-pressure gas refrigerant is discharged from the compressor 91. The high-temperature, high-pressure gas refrigerant discharged from the compressor 91 flows through the flow path switching device 92 to the water-cooled condenser 94. The gas refrigerant becomes low-temperature, low-pressure liquid refrigerant by the water-cooled condenser 94 and flows into the indoor heat exchanger 93. The refrigerant that flows into the indoor heat exchanger 93 evaporates by exchanging heat with the air in the indoor heat exchanger 93, and flows out of the indoor heat exchanger 93 as low-temperature, low-pressure gas refrigerant. The refrigerant that flows out of the indoor heat exchanger 93 flows into the compressor 91 through the flow path switching device 92.

The heat source water flowing out of the water-cooled condenser 94 flows into the heat source water return pipe 62 via the branch pipe 62 a.
The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present disclosure is defined by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims.

1 Water source heat pump unit, 2 Cooling tower, 3 Expansion tank, 4 Pressure regulating valve, 5, 6 Motor valve, 7 Auxiliary boiler, 8 Heat source water pump, 9 Heat source water tank, 10 Solar water heater, 11 Pyranometer, 12 Control device, 20 Heat source unit, 21 Diversion controller, 22 Indoor unit, 40, 91 Compressor, 41 Suction side piping, 42 Discharge side piping, 43 Four-way valve, 44 Heat medium circulation path, 44a First end side, 44b Second end side, 50 Air conditioning heat exchanger, 51 Expansion valve, 52 Heat source water side heat exchanger, 55 Supply air fan, 57 Filter, 61 Heat source water supply pipe, 61a, 62a Branch pipe, 61b, 62b Branch pipe, 62 Heat source water return pipe, 63, 64 Branch pipe, 65 Bypass pipe, 92 A flow path switching device, 93 an indoor heat exchanger, 94 a water-cooled condenser, V1 a first motor-operated valve, V2 a second motor-operated valve, and V3 a third motor-operated valve.

Claims (14)

1. A heating and cooling system, comprising:
A cooling tower that cools the heat source water;
A solar water heater that heats the heat source water;
A plurality of water source heat pump units each performing a cooling operation for cooling a space to be air-conditioned or a heating operation for heating the space;
a heat source water pump for supplying the heat source water stored in a heat source water tank to the plurality of water heat source heat pump units;
A first motor-operated valve disposed between a heat source water outlet of the plurality of water heat source heat pump units and a heat source water inlet of the cooling tower;
a second motor-operated valve disposed between the heat source water outlets of the plurality of water heat source heat pump units and the heat source water inlet of the solar water heater;
a third motor-operated valve disposed between the heat source water outlets of the plurality of water heat source heat pump units and the heat source water inlet of the heat source water tank;
The heat source water outlet of the cooling tower is connected to the inlet of the heat source water tank, and the heat source water outlet of the solar water heater is connected to the inlet of the heat source water tank,
The heating and cooling system further comprises:
A heating and cooling system comprising a control device that controls the first motor-operated valve, the second motor-operated valve, and the third motor-operated valve. The cooling and heating system of claim 1, wherein the control device opens the first motor-operated valve and closes the second motor-operated valve and the third motor-operated valve when the temperature of the heat source water in the heat source water tank exceeds a first threshold temperature during the summer and intermediate seasons at night. The cooling and heating system of claim 2, wherein the control device stops the heat source water pump and stops the cooling tower fan when the temperature of the heat source water in the heat source water tank is equal to or lower than the first threshold temperature during nighttime hours in summer and intermediate seasons. The heating and cooling system of claim 1, wherein the control device opens the third motor-operated valve and closes the first motor-operated valve and the second motor-operated valve when the amount of solar radiation is less than a first reference value and the temperature of the heat source water in the heat source water tank is less than a second threshold temperature in winter. The cooling and heating system of claim 4, wherein the control device opens the first motor-operated valve and closes the second motor-operated valve and the third motor-operated valve when the amount of solar radiation is less than the first reference value and the temperature of the heat source water in the heat source water tank exceeds a third threshold temperature in winter. The heating and cooling system of claim 5, wherein the control device maintains the states of the first motor-operated valve, the second motor-operated valve, and the third motor-operated valve during winter when the amount of solar radiation is less than the first reference value and the temperature of the heat source water in the heat source water tank is equal to or greater than the second threshold temperature and equal to or less than the third threshold temperature. The heating and cooling system of claim 1, wherein the control device opens the second motor-operated valve and closes the first motor-operated valve and the third motor-operated valve when the amount of solar radiation is equal to or greater than a first reference value and the temperature of the heat source water in the heat source water tank is less than a second threshold temperature in winter. The heating and cooling system of claim 7, wherein the control device opens the first motor-operated valve and closes the second motor-operated valve and the third motor-operated valve when the amount of solar radiation is equal to or greater than the first reference value and the temperature of the heat source water in the heat source water tank exceeds a third threshold temperature in winter. The heating and cooling system of claim 8, wherein the control device maintains the states of the first motor-operated valve, the second motor-operated valve, and the third motor-operated valve during winter when the amount of solar radiation is equal to or greater than the first reference value and the temperature of the heat source water in the heat source water tank is equal to or greater than the second threshold temperature and equal to or less than the third threshold temperature. The cooling and heating system of claim 1, wherein the control device opens the first motor-operated valve and closes the second motor-operated valve and the third motor-operated valve when the temperature of the heat source water in the heat source water tank exceeds a first threshold temperature during daytime hours in summer and intermediate seasons. The cooling and heating system of claim 10, wherein the control device opens the third motor-operated valve and closes the first motor-operated valve and the second motor-operated valve during daytime hours in summer and intermediate seasons when the temperature of the heat source water in the heat source water tank is equal to or lower than the first threshold temperature. The heating and cooling system according to any one of claims 2, 3, 10, and 11, wherein the first threshold temperature is a lower limit of the water temperature at which the water source heat pump unit can perform cooling. The heating and cooling system according to any one of claims 4, 6, 7, and 9, wherein the second threshold temperature is 20°C when the heating water temperature of the water source heat pump unit is 5°C or higher and 45°C or lower, and the cooling water temperature of the water source heat pump unit is 7°C or higher and 45°C or lower. The heating and cooling system according to any one of claims 5, 6, 8, and 9, wherein the third threshold temperature is 30°C when the heating water temperature of the water source heat pump unit is 5°C or higher and 45°C or lower, and the cooling water temperature of the water source heat pump unit is 7°C or higher and 45°C or lower.

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