JP2019078501A - Air conditioning system - Google Patents

Abstract

To provide an air conditioning system capable of achieving freezing prevention of a heating medium.SOLUTION: An air conditioning system 1 includes: a first circulation path 5 for allowing a first heating medium to circulate between a first heat source device 3 capable of increasing the temperature of the first heating medium and an outdoor unit 2; a second circulation path 6 for allowing a second heating medium to circulate between a second heat source device 4 capable of decreasing the temperature of the second heating medium and the outdoor unit 2; a second heating medium temperature measurement sensor 37 for measuring the temperature of the second heating medium; an outgoing first heating medium and return second heating medium bypass pipe 25 and an outgoing second heating medium and return first heating medium bypass pipe 35 connected between the first circulation path 5 and the second circulation path 6; a first valve 26 for opening/closing the outgoing first heating medium and the return second heating medium bypass pipe 25; and a second valve 36 for opening/closing the outgoing second heating medium and return first heating medium bypass pipe 35. In the case where the temperature of the second heating medium measured by the second heating medium temperature measurement sensor 37 is equal to or lower than a specific temperature, the first valve 26 and the second valve 36 are brought into an open state.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an air conditioning system that includes an air conditioning heat source that produces cold or heat by using water as a heat medium, and an external conditioner on the air conditioning secondary side.

  Conventionally, in large-scale buildings such as general office buildings, factories, and accommodation facilities, outside air is introduced to ventilate the inside space of the building, and the temperature of the outside air is supplied before the outside air taken in is supplied to the inside space of the building. An external air conditioner that is an outside air conditioner specialized in adjusting the temperature of the interior space of the building or adjusting the humidity of the outside air introduced to bring the interior space of the building closer to a desired humidity. It may be provided on the side. In this air conditioning system having an external air conditioner on the secondary side of the air conditioning, the heat load that must be treated to provide a comfortable environment in the building, such as building load, internal load and outside air load, affects the weather etc. An external unit that specializes in the most fluctuating external air load, and only the ventilation air amount to reduce the overall air conditioning fluctuation factor, and an internal control that circulates the air in the building interior space to process the building load and internal load It is also an air conditioning system that distributes the air of the place where temperature and humidity are different by air conditioning, resulting in energy saving as a whole.

  In the case of the above-mentioned large-scale building, an air conditioning system having high temperature and humidity control performance of the conditioned air is often provided by using an air conditioning heat source which produces cold or warm heat by using water as a heat medium. In large-scale buildings, if the external wall load, which is a building load, is temperature-controlled with a perimeter specialized air conditioner, the internal load is large even in winter and cold heat is often required, and cold heat source and air conditioning heat source using water as a heat medium are required. In many cases, a heat source is required at the same time. Of course, in the external air conditioner, the heat source is required to be cold heat which is cooled or dehumidified according to the outside air temperature and humidity, and heat which is warmed. Since the required cold energy and the required temperature heat fluctuate depending on the season, it may be advantageous in the simplicity of the equipment to adopt an air-cooled heat pump chiller that can easily switch between the cold heat source and the heat source with one device. is there.

  From these things, as an air conditioning system which comprises an external air conditioner, the 1st heat source device (thermal heat source) comprised by air-cooled heat pump chiller etc., the 2nd heat source device (cold heat source), and the 1st heat source A second circulation path for circulating a first heat medium (hot water) between the device and the external air conditioner, and a second heat medium (cold water) for circulation between the second heat source device and the external air conditioner And a second heat medium flow path for circulating a first heat medium for circulating each heat medium between the internal conditioner and each heat source device in parallel with the first circulation path and the second circulation path. A configuration having a flow path is set as a target this time. Then, the first heat medium heated by the first heat source device contributes to the temperature rise of the outside air taken in by the external air conditioner, and the second heat medium cooled by the second heat source device is outside air taken in by the external air machine It is configured to contribute to temperature reduction or dehumidification.

  Furthermore, by increasing the flow rate of the heat medium to be circulated between the external air conditioner and the heat source device, the effect of the heat source device contributing to the temperature change of the heat medium is increased. If the temperature of the air supplied to the interior space of the building is equal to or higher than the ambient air supply temperature set temperature (if it is sufficiently warm), the flow rate of the heat medium in the first circulation path is reduced to In the case (if it is sufficiently cold) or below the set point temperature of the outside air supply (if it is sufficiently dry), the flow rate of the heat medium in the second circulation path will be reduced.

  By the way, for example, when the air conditioning system is operated in a situation where the outside air temperature is low temperature close to the freezing point, the flow rate of the second heat medium circulating in the second circulation path is decreased, or In the external air conditioner, the second heat medium of the second circulation path and the external air conditioner are taken in, despite the situation in which the heat medium circulation is stopped and the second heat medium is likely to freeze. Heat exchange is performed with the outside air via the second heat medium coil in the external air conditioner to further cool the second heat medium. As a result, there is a concern that the second heat medium may freeze in the second circulation path or the second heat medium coil in the external air conditioner, and in some cases, in the external air conditioner having a thin pipe connected to the second circulation path. There is a possibility that the second heat medium coil may be broken.

  On the other hand, the external heat pump is provided with a bypass pipe capable of circulating the second heat medium without passing through the second heat source device with respect to the second heat medium coil in the air conditioner. Technology that forcibly circulates the rated amount of the second heat medium coil in the external air conditioner by the bypass pump in the bypass circuit including the machine (the external heat exchanger in the second heat medium coil) and the bypass pipe (See, for example, Patent Document 1).

Unexamined-Japanese-Patent No. 2004-28476

  However, when the outside temperature is considerably low, it is impossible to catch up with the calorific value of the bypass pump only by forcibly circulating the second heat medium, and the second heat medium is cooled by the outside air and stagnated in the pipe. It is feared that it starts to freeze as a core of ice and it can not prevent freezing of the second heat medium.

  Further, for example, although it is conceivable to separately provide a heater for preventing freezing of the second heat medium in the external air conditioner, it is also possible to install the heater etc. due to the restriction of the installation place etc. is there. When priority is given to the control of the outside air temperature and humidity, it may not be possible to install the outside heat exchanger first heat medium coil inside the outside air upstream side of the outside air conditioner second heat medium coil to preheat outside air.

  The present invention has been made to solve the above-mentioned problems, and an object thereof is to provide an air conditioning system capable of preventing the heat medium from freezing.

  In the following, each means suitable for solving the above object and the like will be described by item. In addition, specific effects and the like are added to the corresponding means as needed.

Means 1. An external air conditioner that takes in the outside air, adjusts temperature and humidity, and supplies it to the space in the building or the internal air conditioner,
An internal air conditioner that circulates air in a space in the building to control the temperature, a first heat source device, and a second heat source device;
A first circulation path enabling circulation of a first heat medium between the first heat source device and the external air conditioner;
A second circulation path enabling circulation of a second heat medium between the second heat source device and the external air conditioner;
A first circulation pump that causes the first heat medium in the first circulation path to flow and circulate in the first circulation path;
And a second circulation pump that causes the second heat medium in the second circulation path to flow and circulate in the second circulation path.
The first heat source apparatus is configured to be capable of raising the temperature of the first heat medium, and the second heat source apparatus is configured to be capable of lowering the temperature of the second heat medium.
In the air conditioning system, the first heat medium contributes to the temperature rise of the outside air taken in the outside air conditioner, and the second heat medium contributes to the temperature decrease of the outside air taken in the outside air machine,
A second heat medium temperature measurement unit that measures the temperature of the second heat medium at the inlet of the second heat source device in the second circulation path;
A first heat medium and a returning second heat medium bypass pipe connected between the first circulation path and the second circulation path, and a second heat medium and a return first heat medium bypass pipe,
A first valve for opening and closing the first heat medium and the second heat medium bypass pipe;
A second valve for opening and closing the forward second heat medium and the return first heat medium bypass pipe;
And a temperature control unit that performs opening / closing control of the first valve and the second valve.
The temperature control means is
The first valve is opened when the temperature of the second heat medium measured by the second heat medium temperature measurement unit is equal to or lower than a specific temperature.
When the first valve is in the open state, the second valve is also in the open state,
When the first valve is in the open state, the first heat medium in the first circulation path flows through the second heat medium bypass pipe and the second heat medium bypass pipe. Flow into the path,
When the second valve is brought into the open state, the second heat medium in the second circulation path passes through the first heat medium bypass pipe and the second heat medium that passes through the second heat medium and the first circulation. An air conditioning system characterized by flowing into a route.

  According to the means 1, when the second heat source device inlet temperature of the second heat medium circulating in the second circulation path is made equal to or lower than the specific temperature, the first valve is opened to thereby perform the first circulation. The relatively high temperature first heat medium circulating in the path flows into the second circulation path and mixes with the second heat medium. Thereby, it is possible to suppress a decrease in the temperature of the second heat medium or to raise the temperature of the second heat medium. For example, in a situation where the outside air temperature is below the freezing point, the second circulation path It is possible to prevent the heat medium from freezing. Therefore, it becomes difficult to perform suitable temperature and humidity control by freezing the second heat medium in the second heat medium coil in the external air conditioner to which the second circulation path or the second circulation path is connected. It is possible to avoid a situation in which the second heat medium coil which is frozen or expanded expands and the second heat medium coil in the external conditioner or the second circulation path is broken.

  Furthermore, for example, the configuration is such that heat exchange is performed without mixing the first heat medium and the second heat medium between the first heat medium of the first circulation path and the second heat medium of the second circulation path. By opening the first valve, it is possible to quickly raise the temperature of the second heat medium compared to the above, and it is possible to cope with relatively rapid temperature changes, as well as performing fine temperature control. Can. In addition, as compared with the case where a heater for preventing freezing of the second heat medium in the second heat medium coil in the external air conditioner is provided in the external air machine, the external air conditioner can be made compact. While being able to do, reduction of the cost concerning freeze prevention of the 2nd heat carrier can be aimed at. Furthermore, it is possible to configure the air conditioning system of the present means by using the existing external air conditioner without the heater as it is, and to prevent the second heat medium from freezing.

  Further, by closing the first valve, heat exchange between the first heat medium and the second heat medium can be avoided, and the first heat medium of the first circulation path, And while preventing the fall of the thermal efficiency of the 2nd heat carrier of the 2nd circulation route, temperature control of each of the 1st heat carrier of the 1st circulation route and the 2nd heat carrier of the 2nd circulation route (temperature management) Can be done relatively easily. Furthermore, since the second valve is also opened when the first valve is opened, the first heat medium of the first circulation path and the second circulation path, and the second heat medium And the first heat medium can flow relatively smoothly into the second circulation path. In particular, for example, the opening degree of the second valve may be the flow rate of the first heat medium in the first heat medium and the returning second heat medium bypass pipe, and the second heat medium bypass pipe in the returning second heat medium and the second heat medium bypass pipe. When the flow rate of the heat medium is adjusted in accordance with the opening degree of the first valve so as to be the same or substantially the same, such an effect is more significantly exerted.

  In addition, as an air conditioning system, for example, even if it is not necessary to cool the outside air taken into the air conditioner, the freezing of the second heat medium is prevented when the outside air temperature is made lower than the specified outside air temperature. In order to achieve this, it is conceivable to provide a function of driving the second circulation pump to forcibly circulate the second heat medium. Furthermore, the low-temperature second heat medium flows into the second heat source apparatus, and the second heat medium is frozen in the heat exchanger (evaporator) of the second heat source apparatus connected to the second circulation path. If the temperature of the second heat medium measured by the second heat medium temperature measuring means falls below the heat source freezing avoidance temperature in order to avoid a situation such as a second heat pump, the second circulation pump by the safety circuit of the second heat source device It is conceivable that the function of protecting the heat exchanger of the second heat source apparatus is activated by stopping the In this case, since the second heat medium can not be circulated even though the temperature of the second heat medium is equal to or lower than the heat source freeze avoidance temperature, the second heat medium is on the outside air conditioner side of the second circulation path. The risk of freezing will increase.

  In this respect, the measurement temperature of the second heat medium temperature measuring means becomes equal to or less than the heat source freezing avoidance temperature by setting the specific temperature at which the first valve is opened as a trigger temperature higher than the heat source freezing avoidance temperature. It is possible to prevent the second circulation pump from being stopped by the heat exchanger protection circuit of the second heat source device. Therefore, it is possible to prevent the second circulation pump from being brought into the stop state, and the second heat medium can not be circulated. Also, even if the second heat medium falls below the heat source freezing avoidance temperature and the second circulation pump is stopped, the first valve is opened to prevent the first circulation path from being opened. The first heat pump can be circulated by the first circulation pump that circulates the heat medium, and the second heat medium mixed with the first heat medium can be circulated. Therefore, by setting the first valve in the open state, the temperature of the second heat medium in the second circulation path becomes equal to or higher than the heat source freeze avoidance temperature and further to the specific temperature or more from the state below the heat source freeze avoidance temperature. It will be possible to raise it by Therefore, the antifreeze effect of the second heat medium is more reliably achieved. Note that “the opening degree of the first valve and the second valve may be proportionally controlled in accordance with the measurement temperature of the second heat medium temperature measurement unit”. In this case, the specific temperature may be set as the center set temperature of the proportional band or may be set as the upper limit value of the proportional band.

Means 2. In the first circulation path, heat exchange is performed between the first outward path for supplying the first heat medium temperature-controlled by the first heat source device to the external air conditioner, and the external air in the external air conditioner And a first return path for supplying the first heat medium to the first heat source device,
In the second circulation path, heat exchange is performed between the second outward path for supplying the second heat medium temperature-controlled by the second heat source device to the external air conditioner, and the external air in the external air conditioner And a second return path for supplying the second heat medium to the second heat source device,
The second heat medium temperature measurement means is provided to be able to measure the temperature of the second heat medium in the second return path,
The forward first heat medium and the returning second heat medium bypass pipe are connected between the first outward path and the second return path,
The forward second heat medium and the return first heat medium bypass pipe are connected between the second outward path and the first return path,
When the first valve is brought into the open state, the first heat medium of the first forward path is transferred to the second return path via the first heat medium and the returning second heat medium bypass pipe. Flow in,
When the second valve is brought into the open state, the second heat medium in the second outward path travels to the first return path via the forward second heat medium and the returning first heat medium bypass pipe. An air conditioning system according to the means 1, characterized in that it flows in.

  According to the means 2, by opening the first valve, the first heat medium of the first forward path flows into the second return path. Therefore, it is possible to mix the first heat medium having a relatively high temperature before heat exchange with the external air conditioner into the second heat medium before flowing into the second heat source apparatus. Therefore, the temperature rise of the second heat medium in the second circulation path can be more reliably achieved, and the low-temperature second heat medium flows into the second heat source device, and the second circulation path of the second heat source device In the above, the second heat medium can be more reliably prevented from freezing. Further, by opening the second valve, the first heat medium of the second forward path flows into the first return path. Therefore, for example, the situation where the temperature of the first heat medium supplied to the external air conditioner is lowered due to the second heat medium of the second circulation path flowing into the first outward path is avoided. Can. In addition, for example, one inlet side of the first heat medium and return second heat medium bypass pipe, and the other inlet side of the second heat medium bypass and return first heat medium bypass pipe connected on the downstream side are connected As in the case where the first heat transfer medium is used, the effect of raising the temperature of the second heat transfer medium using the first heat transfer medium as described above does not work well (for example, the first heat transfer medium and return second Immediately thereafter, a portion of the first heat medium that has flowed into the second circulation path via the heat medium bypass pipe is returned to the first circulation path via the second heat medium and the returning first heat medium bypass pipe. Etc.) can be avoided.

  Further, the first circulation path and the second circulation path in the external air conditioner are connected to the first heat medium coil (heating coil) in the external air conditioner of the external air machine, and the second heat medium in the external air machine Since the water pressure of the first heat medium and the second heat medium is increased by the coil (cooling coil), the first heat medium and the returning second heat medium bypass pipe, the second heat medium and the second heat medium, and the second heat medium By connecting the first return heat medium bypass pipe relatively simply, each of the first heat transfer medium and the second return heat medium bypass pipe, and the second heat transfer medium and the first return heat medium bypass pipe are separately connected. Even if the pump and the like are not installed, only by opening the first valve and the second valve (by the difference in the pressure difference between the inlet and the outlet, it flows more than the heating coil and cooling coil of the external air conditioner Easy) forward first heat medium and return second heat medium bypass And forward to the second heat medium and went back the first heat medium bypass pipe, a first heat medium, and can be circulated through the second heat medium. Accordingly, the configuration can be simplified, the control can be simplified, and the cost can be reduced.

Means 3. The plurality of first heat source devices and the plurality of second heat source devices respectively installed are air-cooled or water-cooled heat pump chillers, and the first heat source is controlled by controlling the number of heat sources when the cooling load requirement of the second heat medium increases. A part of the heat source apparatus is switched to the second heat source apparatus, and the switched heat source apparatus changes the connection from the first circulation path to the second circulation path by switching the valve,
When the thermal load demand of the first heat medium increases, a part of the second heat source apparatus is switched to the first heat source apparatus by heat source number control, and the switched heat source apparatus is switched from the second circulation path to the second circulation path. The air conditioning system according to the means 1 or 2, wherein the connection is changed to the first circulation path.

  According to means 3, in the air-cooled heat pump chiller or the water-cooled heat pump chiller, two heat exchangers are respectively evaporated by switching the flow of the evaporator, the condenser, the compressor and the expansion valve of the refrigeration cycle with a four-way valve It is possible to switch from the condenser to the condenser, to the evaporator, and to switch cold heat and heat, making full use of the device characteristics to reduce initial costs by reducing the number compared to the heat source for cold heat and heat source for heat only. In the present invention, the heat source device can be effectively used in that the heat source dedicated to cold energy and the heat source dedicated to thermal energy are stopped and idle in the middle period.

Means 4. It has an outside air temperature measurement means capable of measuring the outside air temperature taken into the outside air conditioner,
When the outside air temperature measured by the outside air temperature measurement means is lower than or equal to the specified outside air temperature, the second heat medium circulation pump built in one of the plurality of second heat source devices is driven at the rated flow rate Forced circulation control for forcedly circulating the second heat medium as
The specified outside air temperature is set to a temperature at which the forced circulation control is started prior to the heat medium mixing control in which the first valve is brought into the open state. 3. An air conditioning system according to any one of 3. to 3.

  According to the means 4, in the stage where the heat medium mixing control is started, the forced circulation control has already been performed, and the second heat medium which is still hot in the second heat medium coil in the external conditioner is forcedly circulated. It is in a state of Therefore, for example, when the measurement temperature of the second heat medium temperature measurement unit is made equal to or lower than the specific temperature, the second heat medium in the second circulation path must be circulated only by the first circulation pump. In comparison, the second heat medium that is mixed with the first heat medium that has flowed into the second circulation path via the first heat medium and the second heat medium bypass pipe that is returned and heated up is relatively smooth in the second circulation path. Can be circulated. Therefore, the situation where the second heat medium freezes in the second circulation path can be prevented more reliably. The “second heat medium circulation pump” may be the “second circulation pump”.

It is an explanatory view showing a schematic structure of an air-conditioning system. It is explanatory drawing which shows the relationship of the temperature of the 2nd heat medium measured by the 2nd heat medium measurement sensor, and the opening degree of a 1st valve by the concept of a proportional zone. It is explanatory drawing which shows the structure regarding the connection between the heat-source apparatus of the air conditioning system in another embodiment, and a 1st circulation path and a 2nd circulation path.

  Hereinafter, an embodiment will be described with reference to the drawings. As shown in FIG. 1, an air conditioning system 1 provided in a building such as a building takes in outside air, adjusts temperature and humidity, and supplies an external air conditioner 2 to a space in the building or an internal air conditioner (not shown). , The first heat source device 3, the second heat source device 4, the first heat source device 3, and the external air conditioner 2, and the first circulation path 5 enabling circulation of the first heat medium, and the second heat source The apparatus 4 and the second circulation path 6 enabling circulation of the second heat medium between the external air conditioner 2 are provided. Further, the first heat source device 3 includes a first circulation pump 7 that causes the first heat medium in the first circulation path 5 to flow and circulate the first heat medium in the first circulation path 5. The second heat source device 4 has a second circulation path A second circulation pump 8 is provided to cause the second heat medium 6 to flow and circulate in the second circulation path 6. Furthermore, the first heat source device 3 is configured to be capable of raising the temperature of the first heat medium, and the second heat source device 4 is configured to be capable of lowering the temperature of the second heat medium. Accordingly, the first heat medium contributes to the temperature rise of the outside air taken in the external air conditioner 2, and the second heat medium causes the temperature decrease of the outside air taken in the external air machine 2, or the surface air condensation of the heat exchanger It is configured to contribute to dehumidification. As the first heat medium and the second heat medium, heat mediums having the same components as each other are used.

  In addition, the first heat source device 3 and the second heat source device 4 of the present embodiment are each configured by an air-cooling heat pump chiller and installed on the roof of a building. A water-cooled heat pump chiller may be used in which a condenser (evaporator) is connected to a cooling water piping system (not shown). Furthermore, in the present embodiment, six air-cooled heat pump chillers are provided, three of which (the three on the right in FIG. 1) are used as the first heat source device 3, and the remaining three (the left of FIG. 1). 3) are used as the second heat source device 4. As the second heat source device 4, the number of heat pumps to be used as the first heat source device 3 among the six heat pumps by changing the direction of the circulation cycle of the refrigerant in the heat pump according to the change of the season etc. It is also possible to change the ratio of the number used as appropriate.

  Moreover, although illustration is abbreviate | omitted, the 1st heat source apparatus 3 and the 2nd heat source apparatus 4 are air heat exchangers which perform heat exchange between a refrigerant | coolant and external air, in the case of an air-cooled heat pump chiller, and said 1st A water heat exchanger that performs heat exchange between a heat medium or the second heat medium and a refrigerant, a compressor, an expansion valve, an air heat exchanger, a compressor, a water heat exchanger, and And a refrigerant circulation path for circulating the refrigerant to the expansion valve. The water heat exchanger is a shell and tube type, for example, a tube connected to the first circulation path 5 or the second circulation path 6 to flow the first heat medium or the second heat medium, and a part of the refrigerant circulation path Inside the shell which comprises, heat exchange is performed between the 1st heat carrier of a tube, or the 2nd heat carrier, and the refrigerant in a shell. The water heat exchanger may be a plate heat exchanger but is similar.

  The external air conditioner 2 includes an external air intake 11 for taking in external air, a filter (not shown) for preventing the entry of foreign matter, and a cooling coil 12 connected to the second circulation path 6 (external heat generator second heat medium coil) , The heating coil 13 (the first heat medium coil in the external air conditioner) connected to the first circulation path 5, the vapor spray 14 capable of humidifying the taken-in external air, and the external air taken in the external air conditioner 2 And a fan 15 for generating an air flow for supplying the taken outside air to the space inside the building.

  The cooling coil 12 is disposed closer to the outside air intake 11 than the heating coil 13. For example, when operating the air conditioning system 1 in a state where the humidity of the outside air is high, the outside air taken into the outside air conditioner 2 is first cooled by the cooling coil 12, and the water vapor in the outside air is condensed. As a result, dehumidification of the taken-in outside air is performed, and then the outside air cooled to below the set temperature for dehumidification is heated by the heating coil 13 to the set temperature or a temperature close thereto, and the building It is supplied to the inner space side.

  The first circulation path 5 is connected between the water heat exchanger (condenser) outlet of the first heat source device 3 and the inlet of the heating coil 13 of the external air conditioner 2 and temperature-controlled by the first heat source device 3 It is connected between the first forward path 21 for supplying the first heat medium to the air conditioner 2, the outlet of the heating coil 13 of the air conditioner 2, and the water heat exchanger inlet of the first heat source device 3, And a first return path 22 for supplying to the first heat source device 3 the first heat medium of which heat exchange has been performed with the outside air. Further, the first return path 22 is provided with a first expansion tank 23.

  The second circulation path 6 is connected between the outlet of the water heat exchanger (evaporator) of the second heat source device 4 and the inlet of the cooling coil 12 (the second heat medium coil in the external air conditioner) of the external air conditioner 2, The second outward path 31 for supplying the second heat medium temperature-controlled by the second heat source device 4 to the air conditioner 2, the outlet of the cooling coil 12 of the air conditioner 2, and the water heat exchanger inlet of the second heat source device 4 And a second return path 32 for supplying to the second heat source device 4 a second heat medium of which heat exchange has been carried out with the outside air in the external air conditioner 2. Further, a second expansion tank 33 is provided in the second return path 32.

  The air conditioning system 1 according to the present embodiment includes the first and second heat medium bypass pipes 25 connected between the first outward path 21 and the second return path 32, and the second outward path 31; A forward second heat medium and return first heat medium bypass pipe 35 connected between the first return path 22 and a first valve 26 for opening and closing the first heat medium and return second heat medium bypass pipe 25. , And a second valve 36 for opening and closing the second heat medium and return first heat medium bypass pipe 35. Then, when the first valve 26 is opened, the first heat medium in the first forward path 21 flows into the second return path 32 via the first heat medium and the second heat medium bypass pipe 25. When the second valve 36 is opened, the second heat medium in the second forward path 31 flows into the first return path 22 via the second heat medium bypass and the first heat medium bypass pipe 35. It is configured to In FIG. 1, for convenience, the second circulation path 6 and the first heat medium and return second heat medium bypass pipe 25 are connected to the first circulation path 5 and the second heat medium and return second time. The first circulation medium 6 is basically the same in diameter as the first circulation passage 5, and the first heat medium and the return second heat medium bypass pipe 25 are illustrated. The diameter is the same as that of the forward second heat medium and return first heat medium bypass pipe 35. Here, although depending on the number division of the first heat source device 3 and the second heat source device 4, the respective flow rates of the first heat medium and the second heat medium flowing through the first circulation path 5 and the second circulation path 6 are approximately The flow of up to about 30% determines the relationship between the first heat medium and return second heat medium bypass pipe 25 and the second heat medium and return first heat medium bypass pipe 35, and the first valve 26 and the second valve are determined. If the flow rate of 36 is determined, it becomes possible to suppress unnecessary fluctuation of the temperatures of the first circulation path 5 and the second circulation path 6 each having an expansion tank and to keep the pressure at a certain level.

  Furthermore, the air conditioning system 1 includes a second heat medium temperature measurement sensor 37 as a second heat medium temperature measurement unit that measures the temperature of the second heat medium in the second return path 32. In the present embodiment, the second heat medium temperature measurement sensor 37 is a second heat medium at a portion of the second return path 32 downstream of the connection portion with the first heat medium and the returning second heat medium bypass pipe 25. The temperature of the medium can be measured.

  Further, in the present embodiment, the temperature controller 41 is provided as a temperature control unit that performs the opening and closing control of the first valve 26 and the second valve 36 based on the temperature measured by the second heat medium temperature measurement sensor 37. There is. The temperature controller 41 monitors the measured temperature of the second heat medium temperature measurement sensor 37, and opens the first valve 26 when the measured temperature of the second heat medium temperature measurement sensor 37 is made equal to or less than the "specific temperature". It is comprised so that execution of the heat-medium mixing control made into a state is possible. In the present embodiment, the heat medium mixing control is performed such that the temperature of the second heat medium supplied to the second heat source device 4 is 7 degrees (Centigrade; the same applies hereinafter) or more. More specifically, as shown in FIG. 2, "10 degrees" is set as the "specific temperature", from which the minute opening signal is sent to the first valve 26 and the second valve 36, and further, the second heat The “proportional band” is set so that the opening degree of the first valve 26 is maximized when the measured temperature of the medium temperature measurement sensor 37 is set to “0 degrees or less”, and the second heat medium temperature measurement sensor 37 The opening degree of the first valve 26 is proportionally controlled according to the rise and fall of the measured temperature.

  Further, the second valve 36 is constituted by a valve having the same shape as the first valve 26, and is controlled by the temperature controller 41 so that the opening degree of the second valve 36 is always the same as the first valve 26. The air conditioning system 1 is configured to be capable of switching on / off of the antifreeze mode in which the heat medium mixing control is performed. For example, in a situation where the outside air temperature is relatively high and there is no fear of freezing of the second heat medium etc., the heat medium mixing control is not performed even if the temperature of the second heat medium becomes lower than the specified temperature (10 degrees or less) Thus, the setting for turning off the antifreeze mode is performed.

  Furthermore, the air conditioning system 1 is installed between the outside air intake 11 of the outside air conditioner 2 and the cooling coil 12, and measures the outside air temperature as an outside air temperature measuring means capable of measuring the outside air temperature taken into the outside air conditioner 2. A sensor 42 is provided. Further, in the present embodiment, when the measured temperature of the outside air temperature measurement sensor 42 is equal to or less than the “specified outside air temperature”, it is incorporated in one of the plurality of second heat source devices 4 located at the leftmost in FIG. The forced circulation control is performed such that the second heat pump is forcedly circulated with the second circulation pump 8 being driven at the rated flow rate and driven.

  In the present embodiment, “four degrees” is set as the “specified outside air temperature”. That is, in general, since the outside air temperature in the vicinity of the external air conditioner 2 becomes 4 degrees or less before the second heat medium of the second circulation path 6 becomes 10 degrees or less, forced control is performed before heat medium mixing control. The circulation control is started (in the stage where the heat medium mixing control is performed, the forced circulation control is already performed).

  Further, in the air conditioning system 1 of the present embodiment, the second heat medium of low temperature flows into the second heat source apparatus 4, and the second heat medium is frozen in the water heat exchanger tube in the second heat source apparatus 4. And the second heat medium temperature measurement in order to avoid a situation in which the refrigerant can not evaporate in the shell of the water heat exchanger in the second heat source device 4 and liquid backs up to the compressor at the latter stage of the refrigeration cycle to break the compressor. The second circulation pump 8 for circulating the second heat medium of the second circulation path 6 when the temperature of the second heat medium measured by the sensor 37 is equal to or lower than the preset “heat source freeze avoidance temperature” is set. It has a function to maintain it as a stopped state. In the present embodiment, “7 degrees” is set as the “heat source freeze avoidance temperature”. That is, as described above, when the measurement temperature of the second heat medium temperature measurement sensor 37 is 10 degrees or less, the heat medium mixing control is started, and the second heat medium supplied to the second heat source device 4 Since the temperature of the second pump is adjusted to be 7 degrees or more, basically, the second circulation pump 8 is prevented from being forcibly stopped.

  As described above in detail, in the present embodiment, when the temperature of the second heat medium circulating in the second circulation path 6 is equal to or lower than the specific temperature (10 degrees in this example), the first valve 26 By being in the open state, the relatively high temperature first heat medium circulating in the first circulation path 5 flows into the second circulation path 6 and mixes with the second heat medium. Thereby, it is possible to suppress a decrease in the temperature of the second heat medium or to raise the temperature of the second heat medium. For example, in the situation where the outside air temperature is below the freezing point, it is taken into the air conditioner 2 It is possible to prevent a situation in which the second heat medium is frozen in the cooling coil 12 and the second circulation path 6 of the external conditioner 2 where heat exchange is performed with the outside air. Accordingly, freezing of the second heat medium in the cooling coil 12 and the second circulation path 6 makes it difficult to perform suitable temperature and humidity control, or the frozen second heat medium expands and cools down. It is possible to avoid a situation in which the coil 12 and the second circulation path 6 are damaged.

  Furthermore, for example, heat exchange is performed between the first heat medium of the first circulation path 5 and the second heat medium of the second circulation path 6 without mixing the first heat medium and the second heat medium. Compared with the above configuration, by opening the first valve 26, it is possible to quickly raise the temperature of the second heat medium, and it is also possible to cope with relatively rapid temperature changes, as well as for fine temperature control. Can also do. In addition, for example, as compared with the case where a heater for preventing freezing of the second heat medium of the cooling coil 12 is provided inside the external air conditioner 2, the external air conditioner 2 can be made compact, and (2) It is possible to reduce the cost required to prevent the heat medium from freezing. Furthermore, it is also possible to configure the air conditioning system 1 of the present embodiment by using the existing external air conditioner without the heater as it is, and to prevent the second heat medium from freezing.

  In addition, by closing the first valve 26, it is possible to avoid heat exchange between the first heat medium and the second heat medium, and the first heat of the first circulation path 5 can be prevented. The heat efficiency of the medium and the second heat medium of the second circulation path 6 is prevented from being reduced, and the temperatures of the first heat medium of the first circulation path 5 and the second heat medium of the second circulation path 6 Adjustment (temperature control) can be performed relatively easily. Further, the second valve 36 is controlled to have the same degree of opening as the first valve 26, and the first heat medium and return second heat medium bypass pipe 25 and the second heat medium and return first heat medium are returned. Since the flow rates of the medium bypass pipe 35 are substantially the same, the pressures of the first heat medium and the second heat medium of the first circulation path 5 and the second circulation path 6 can be suitably maintained. The first heat medium can flow into the second circulation path 6 relatively smoothly.

  Further, by opening the first valve 26, the first heat medium of the first forward path 21 flows into the second return path 32. Therefore, the first heat medium having a relatively high temperature before being heat-exchanged by the external air conditioner 2 can be mixed into the second heat medium before flowing into the second heat source device 4. Therefore, the temperature rise of the second heat medium in the second return path 32 can be more reliably achieved, and the low-temperature second heat medium flows into the second heat source device 4, and the second heat source device 4 It is possible to prevent more reliably the situation in which the second heat medium is frozen in the circulation path 6. Further, by opening the second valve 36, the first heat medium of the second outward path 31 flows into the first return path 22. Therefore, for example, when the second heat medium in the second circulation path 6 flows into the first outward path 21, the temperature of the first heat medium supplied to the external air conditioner 2 is lowered. It can be avoided. In addition, for example, the first inlet / outlet second heat carrier bypass pipe 25 and the second inlet / outlet first heat carrier bypass pipe 35 are directly connected to the outlet of the other inlet. As in the case where the sides are connected, the effect of raising the temperature of the second heat medium using the first heat medium as described above can not be achieved well (for example, the first heat medium and return Immediately after that, a portion of the first heat medium that has flowed into the second circulation path 6 via the second heat medium bypass pipe 25 passes the first heat medium bypass pipe 35 and the second heat medium bypass pipe 35, It is possible to avoid a situation such as being returned to the circulation route 5).

  Further, the destination connected to the first circulation path 5 and the second circulation path 6 in the external air conditioner 2 is constituted by the heating coil 13 and the cooling coil 12 of the external air conditioner 2, and a first heat medium, Since the water pressure of the second heat medium is high, the first heat medium and return second heat medium bypass pipe 25 and the second heat medium and return first heat medium bypass pipe 35 are relatively simple. By connecting to the first heat medium and return second heat medium bypass pipe 25 and the second heat medium and return first heat medium bypass pipe 35 going forward, even if a separate pump or the like is not installed, Only when the first valve 26 and the second valve 36 are opened (the flow tends to flow more easily than the heating coil 13 and the cooling coil 12 of the air conditioner 2 due to the difference in pressure difference between the inlet and the outlet) Heat medium and return second heat medium bypass pipe 25 And, the forward second heat medium and went back the first heat medium bypass pipe 35, the first heat medium, and can be circulated through the second heat medium. Accordingly, the configuration can be simplified, the control can be simplified, and the cost can be reduced.

  Furthermore, the temperature of the second heat medium temperature sensor 37 is the temperature of the second heat medium in the portion of the second return path 32 downstream of the connection portion with the first heat medium and the returning second heat medium bypass pipe 25. It is provided to be able to measure. Therefore, it is possible to measure the temperature of the second heat medium after being mixed with the first heat medium that flows forward through the first heat medium and the returning second heat medium bypass pipe 25. Therefore, when the temperature measured by the second heat medium temperature measurement sensor 37 shifts from a state below the specific temperature to a state exceeding the specific temperature, the first valve 26 and the second valve 36 can be immediately closed. It is possible to prevent the situation where the first heat medium heated to a sufficient temperature by the first heat source device 3 is supplied to the second circulation path 6 more than necessary.

  In addition, even if it is not necessary to cool the outside air taken into the air conditioner 2, the measurement temperature of the air temperature measuring sensor 42 capable of measuring the outside air temperature taken into the air conditioner 2 is a specified outside air temperature ( In this example, if it is 4 degrees or less, it is incorporated in one of the plurality of second heat source devices 4 among the plurality of second heat source devices 4, for example, at the leftmost position in FIG. The forced circulation control is performed to forcibly drive the second circulation pump 8 at the rated flow rate and forcibly circulate the second heat medium in the second circulation path 6. By performing forced circulation control, it is suppressed that the second heat medium is retained and easily crystallized, and the heat generated by the drive of the second circulation pump 8 is added to the second heat medium. It is possible to suppress freezing of the heat medium.

  In addition, the measured temperature (specific external temperature) of the outside air temperature measurement sensor 42, which is the trigger of the start of forced circulation control, causes the first valve 26 and the second valve 36 to be opened, and the first heat medium and the second The temperature of the second heat medium in the second return path 32 which is triggered to start the heat medium mixture control is earlier than the specific temperature (10 degrees in this example) prior to the heat medium mixture control of mixing with the heat medium The temperature at which forced circulation control will be started (4 degrees in this example; in general, the outside air temperature will be 4 degrees or less before the second heat medium becomes 10 degrees or less) It is set to. That is, at the stage where the heat medium mixing control is started, the forced circulation control has already been performed, and the second heat medium is in a state of being forcedly circulated in the second circulation path 6. For this reason, when the measured temperature of the second heat medium temperature measurement sensor 37 is set to a specific temperature (10 degrees in this example) or less, for example, the second heat path in the second circulation path 6 with only the first circulation pump 7 Compared with a configuration in which the medium has to be circulated, the temperature is mixed with the first heat medium that has flowed into the second circulation path 6 via the first heat medium and the second heat medium bypass pipe 25 that comes back. The second heat medium can be circulated relatively smoothly to the second circulation path 6. Therefore, the situation where the second heat medium is frozen in the second circulation path 6 can be more reliably prevented.

  Further, in the air conditioning system 1 of the present embodiment, when the measured temperature of the second heat medium temperature measurement sensor 37 is equal to or lower than the heat source freeze avoidance temperature (7 degrees in this example), the water heat exchange in the second heat source device 4 The circulation of the second heat medium in the second circulation path 6 is stopped in order to avoid a situation such as the second heat medium freezing in the tube of the vessel.

  In this respect, according to the present embodiment, the specific temperature (10 degrees in this example) at which the first valve 26 is opened is set higher than the heat source freeze avoidance temperature (7 degrees in this example) By doing this, it is possible to control the heat source inlet temperature precisely while suppressing the measured temperature of the second heat medium temperature measuring sensor 37 from becoming the heat source freeze avoidance temperature or less. Therefore, it is possible to prevent the second circulation pump 8 from being brought into the stopped state, and the second heat medium can not be circulated. In addition, even if the second heat medium falls below the heat source freeze avoidance temperature and the second circulation pump 8 is in the stop state, the first valve 26 is opened so that the first circulation path is opened. The first heat pump can be caused to flow into the second circulation path 6 by the first circulation pump 7 that circulates the first heat medium 5, and the second heat medium mixed with the first heat medium can be circulated. Therefore, by setting the first valve 26 in the open state, the temperature of the second heat medium in the second circulation path 6 is not less than the heat source freeze avoidance temperature, the heat source freeze avoidance temperature or more, and further, the specific temperature or more It is possible to raise it by Therefore, the antifreeze effect of the second heat medium is more reliably achieved.

  In addition, it is not limited to the description content of the said embodiment, For example, you may implement as follows. Of course, other applications and modifications not illustrated below are naturally possible.

  (A) In the above embodiment, the first heat medium and return second heat medium bypass pipe 25 are connected between the first forward path 21 and the second return path 32, and the second heat medium return and return first path are connected. The heat medium bypass pipe 35 is connected between the second outward path 31 and the first return path 22, but the first heat medium and the return second one for the first circulation path 5 and the second circulation path 6. It is also possible to change the connection points of the heat medium bypass pipe 25 and the second heat medium and return first heat medium bypass pipe 35 going forward. However, if the outlet of the second heat medium and the return first heat medium bypass pipe 35 is connected to the first way 21, the temperature of the first heat medium supplied to the heating coil 13 of the external air conditioner 2 is compared And there is a concern that the temperature of the outside air taken in the external air conditioner 2 can not be suitably increased, and the second heat medium and the return first heat medium bypass pipe 35 are Since it becomes necessary to separately install a pump or the like for causing the second heat medium of the second circulation path 6 to flow into the first forward path 21 via the second circulation path 6, the second heat medium bypass and the first heat medium bypass pipe 35 are It is desirable to be connected between the second outward path 31 and the first return path 22.

  Further, the first heat medium having a relatively high temperature before heat exchange with the external air conditioner 2 can be supplied to the second circulation path 6, and the first heat medium and the returning second heat medium bypass pipe 25 can be used. Via the first heat medium and the returning second heat medium bypass pipe 25 so that it is not necessary to separately install a pump or the like for causing the first heat medium of the first circulation path 5 to flow into the second circulation path 6. Is preferably connected between the first outward path 21 and the second return path 32. Furthermore, regarding the second heat medium temperature measurement sensor 37, the temperature of the second heat medium mixed with the first heat medium that has flowed into the second circulation path 6 via the first heat medium and the returning second heat medium bypass pipe 25 It is desirable to be provided at a location downstream of the outlets of the first heat medium and the return second heat medium bypass pipe 25 in the second return path 32 in order to measure the In order to measure the temperature of the second heat medium more accurately, it is desirable that the second return path 32 be provided in the vicinity of the second heat source device 4.

  (B) Further, in the above embodiment, the adjustment of the opening degree of the first valve 26 and the second valve 36 is configured to be adjustable steplessly according to the measurement temperature of the second heat medium temperature measurement sensor 37 It may be configured to be changed stepwise according to the measurement temperature of the second heat medium temperature measurement sensor 37. The shapes and sizes of the first valve 26 and the second valve 36 may be different, and the flow rate of the first heat medium in the first valve 26 when the first valve 26 is opened. The opening degree of the second valve 36 may be adjusted so that the flow rate of the second heat medium in the second valve 36 becomes approximately the same.

  (C) In the above embodiment, regarding the adjustment of the flow rates of the first heat medium and the second heat medium in the first circulation path 5 and the second circulation path 6, the first circulation pump 7 and the second circulation The configuration may be performed by switching only the pump 8 on and off, or the number of revolutions per minute of the motor of the circulation pumps 7 and 8 can be changed, or the first circulation path 5 and the second circulation path 6 Alternatively, the flow rates of the first heat medium and the second heat medium may be appropriately changed by providing a control valve capable of adjusting the opening degree.

  In addition, the trigger of the start of forced circulation control for forcibly driving the second circulation pump 8 is not "making the measured temperature of the outside air temperature measuring sensor 42 fall below the specified outside air temperature", but "the second heat medium temperature" The temperature measured by the measurement sensor 37 may be set to be equal to or lower than the forced circulation start temperature higher than the specific temperature. In the above embodiment, the first circulation path 5 and the second circulation path 5 are provided by the first circulation pump 7 built in the first heat source device 3 and the second circulation pump 8 built in the second heat source device 4. The first heat medium and the second heat medium are circulated in the circulation path 6, but instead of or in addition to such a configuration, the first heat medium in the first circulation path 5 and the second heat path 6 A circulation pump may be provided to circulate the medium and the second heat medium.

  (D) Although not mentioned in detail in the above embodiment, as shown in FIG. 3, the first heat source device 3 and the second heat source device 4 each configured by the air-cooled heat pump chiller 51 are the second heat medium When the demand for cold heat load increases, part of the first heat source apparatus 3 is switched to the second heat source apparatus 4 by the heat source number control, and switching of the heat source apparatus 3 switches the valve 52 to the second circulation path from the first circulation path 5 The connection is changed to 6, and when the thermal load demand of the first heat medium increases, the second heat source device 4 is switched to the first heat source device 3 by heat source number control, and switching of the valve 52 to the switched heat source device The connection may be changed from the second circulation path 6 to the first circulation path 5.

  In this case, two heat exchangers are respectively evaporated from the evaporator to the condenser and evaporated from the condenser by switching the flow of the evaporator, the condenser, the compressor, and the expansion valve of the refrigeration cycle of the air-cooled heat pump chiller 51 with a four-way valve. It is possible to reduce the initial cost by reducing the number of units that can be switched to the unit and to switch cold heat and thermal heat, and to reduce the number of heat sources compared to the cold heat dedicated heat source and thermal heat dedicated heat source. The heat source device can be effectively used by adopting this configuration, since a part of the heat source dedicated to heat is stopped and idles.

  The number of first heat source devices 3 and the number of second heat source devices 4 are not particularly limited either, and can be changed as appropriate. In addition, as the first heat source device 3 and the second heat source device 4, a water-cooled heat pump chiller may be adopted. Furthermore, the number of external air conditioners 2 is not particularly limited, and a plurality of external air conditioners 2 that can commonly use the first heat source device 3 and the second heat source device 4 may be provided. . In addition, in the configuration having a plurality of external air conditioners 2, the flow rates and the like of the first heat medium and the second heat medium to each external air conditioner 2 may be separately controllable, or collectively It may be configured to control.

  (E) An air conditioning heat source that produces cold or heat using water as the heat medium, and an air conditioning system equipped with an external air conditioner on the air conditioning secondary side are often installed in parallel in the vicinity of the external air conditioner If tapping is arranged at the time of new construction in each of the first outward path 21 and the first return path 22 of the first circulation path 5 and the second outward path 31 and the second return path 32 of the second circulation path 6 It is easy to install the first heat medium and return second heat medium bypass pipe 25 and the second heat medium and return first heat medium bypass pipe 35 after construction with a little instrumentation work. Can be added to

  DESCRIPTION OF SYMBOLS 1 ... Air conditioning system, 2 ... Outside air conditioner, 3 ... 1st heat source device, 4 ... 2nd heat source device, 5 ... 1st circulation path, 6 ... 2nd circulation path, 7 ... 1st circulation pump, 8 ... 2nd Circulating pump 12 Cooling coil 13 Heating coil 21 First forward path 22 First return path 25 First heat medium and return second heat medium bypass pipe 26 First valve 31st 31st 2 outward path, 32: second return path, 35: forward second heat medium and return first heat medium bypass pipe, 36: second valve, 37: second heat medium temperature measurement sensor, 41: temperature controller, 42: outside Temperature measurement sensor.

Claims (4)

An external air conditioner that takes in the outside air, adjusts temperature and humidity, and supplies it to the space in the building or the internal air conditioner,
An internal air conditioner that circulates air in a space in the building to control the temperature, a first heat source device, and a second heat source device;
A first circulation path enabling circulation of a first heat medium between the first heat source device and the external air conditioner;
A second circulation path enabling circulation of a second heat medium between the second heat source device and the external air conditioner;
A first circulation pump that causes the first heat medium in the first circulation path to flow and circulate in the first circulation path;
And a second circulation pump that causes the second heat medium in the second circulation path to flow and circulate in the second circulation path.
The first heat source apparatus is configured to be capable of raising the temperature of the first heat medium, and the second heat source apparatus is configured to be capable of lowering the temperature of the second heat medium.
In the air conditioning system, the first heat medium contributes to the temperature rise of the outside air taken in the outside air conditioner, and the second heat medium contributes to the temperature decrease of the outside air taken in the outside air machine,
Second heat medium temperature measurement means for measuring the temperature of the second heat medium at the inlet of the second heat source device in the second circulation path;
A first heat medium and a returning second heat medium bypass pipe connected between the first circulation path and the second circulation path, and a second heat medium and a return first heat medium bypass pipe,
A first valve for opening and closing the first heat medium and the second heat medium bypass pipe;
A second valve for opening and closing the forward second heat medium and the return first heat medium bypass pipe;
And a temperature control unit that performs opening / closing control of the first valve and the second valve.
The temperature control means is
The first valve is opened when the temperature of the second heat medium measured by the second heat medium temperature measurement unit is equal to or lower than a specific temperature.
When the first valve is in the open state, the second valve is also in the open state,
When the first valve is in the open state, the first heat medium in the first circulation path flows through the second heat medium bypass pipe and the second heat medium bypass pipe. Flow into the path,
When the second valve is brought into the open state, the second heat medium in the second circulation path passes through the first heat medium bypass pipe and the second heat medium that passes through the second heat medium and the first circulation. An air conditioning system characterized by flowing into a route. In the first circulation path, heat exchange is performed between the first outward path for supplying the first heat medium temperature-controlled by the first heat source device to the external air conditioner, and the external air in the external air conditioner And a first return path for supplying the first heat medium to the first heat source device,
In the second circulation path, heat exchange is performed between the second outward path for supplying the second heat medium temperature-controlled by the second heat source device to the external air conditioner, and the external air in the external air conditioner And a second return path for supplying the second heat medium to the second heat source device,
The second heat medium temperature measurement means is provided to be able to measure the temperature of the second heat medium in the second return path,
The forward first heat medium and the returning second heat medium bypass pipe are connected between the first outward path and the second return path,
The forward second heat medium and the return first heat medium bypass pipe are connected between the second outward path and the first return path,
When the first valve is brought into the open state, the first heat medium of the first forward path is transferred to the second return path via the first heat medium and the returning second heat medium bypass pipe. Flow in,
When the second valve is brought into the open state, the second heat medium in the second outward path travels to the first return path via the forward second heat medium and the returning first heat medium bypass pipe. The air conditioning system according to claim 1, wherein the air flow is introduced. The plurality of first heat source devices and the plurality of second heat source devices respectively installed are air-cooled or water-cooled heat pump chillers, and the first heat source is controlled by controlling the number of heat sources when the cooling load requirement of the second heat medium increases. A part of the heat source apparatus is switched to the second heat source apparatus, and the switched heat source apparatus changes the connection from the first circulation path to the second circulation path by switching the valve,
When the thermal load demand of the first heat medium increases, a part of the second heat source apparatus is switched to the first heat source apparatus by heat source number control, and the switched heat source apparatus is switched from the second circulation path to the second circulation path. The air conditioning system according to claim 1 or 2, wherein the connection is changed to the first circulation path. It has an outside air temperature measurement means capable of measuring the outside air temperature taken into the outside air conditioner,
When the outside air temperature measured by the outside air temperature measurement means is lower than or equal to the specified outside air temperature, the second heat medium circulation pump built in one of the plurality of second heat source devices is driven at the rated flow rate Forced circulation control for forcedly circulating the second heat medium is performed,
The specified external air temperature is set to a temperature at which the forced circulation control is started prior to the heat medium mixing control in which the first valve is in the open state. The air conditioning system according to any one of 1 to 3.

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