JP2006329453A - Radiation cooling system and control method thereof - Google Patents

Abstract

A radiant cooling system capable of preventing condensation of a radiant panel and a method for controlling the radiant panel when cooling the room by supplying cold water from a refrigeration apparatus to the radiant panel.
A radiation cooling system includes an air temperature measurement device that measures the air temperature of a space to be air-conditioned, a water temperature measurement device that measures the temperature of cold water supplied from a water chiller 50, and a control unit 60. The control unit 60 determines the dew point temperature of the space to be air-conditioned from the measured temperature assuming that the humidity of the space 11 to be air-conditioned is a predetermined humidity (for example, relative humidity is 95% RH). A determination unit 61, a threshold determination unit 62 that determines a temperature that is higher than the determined dew point temperature by a predetermined temperature (for example, 1 ° C. to 3 ° C.) as a threshold, and the determined threshold and the temperature of the cold water are compared. A chiller control signal generation unit 30 that generates a control signal to the chiller 50 based on the comparison result of the comparison unit 63 is provided.
[Selection] Figure 1

Description

  The present invention relates to a radiant cooling system that supplies cold water flowing from a refrigeration apparatus to a radiant panel disposed in a room where air conditioning is to be performed, and cools the room with cold heat radiated from the radiant panel.

The term “radiation panel” used in the following sentences is explained.
A radiant panel refers to a panel provided on the ceiling and floor in order to give hot or cold heat to the room, and is referred to as a “radiant panel” because the hot or cold heat is supplied in the form of “radiation”.
Radiant panels have the following advantages.
(1) In the case of cooling, cooling is possible even if the temperature of the chilled water is somewhat high. Specifically, cooling is possible even when the chilled water temperature is about 13 ° C. (normally the chilled water temperature is 7 ° C.).
(2) Since it is a panel, a large area can be cooled or heated simultaneously.

  In an air conditioner that performs radiant cooling by installing a radiant panel on the ceiling, wall, floor, etc. of a room and flowing a heat medium such as cold water through the radiant panel, condensation occurs if the surface of the radiant panel is too cold. Occurs and causes problems such as getting wet in the room.

  In an air conditioner that performs radiant cooling by placing radiant panels on the floor and ceiling, and flowing cold water through a tube embedded in the radiant panel, it does not cause condensation while detecting room temperature, room humidity, and panel surface temperature. In addition, a technique for controlling the panel surface temperature has been proposed (see, for example, Patent Document 1).

In such a technique, the absolute humidity (moisture content [gr] / air mass [gr]) in the room is obtained based on the room temperature and the room humidity, and the relative humidity (water vapor amount) of the air is also obtained near the floor surface. The bed temperature is controlled so that (saturated water vapor amount) does not exceed A%.
Here, the relative humidity A% is a threshold value, but is a numerical value including a safety factor, and can be selected from 60 to 95%.

However, with such a technique, it is difficult to accurately detect the panel surface temperature and the room humidity over a long period of time, regardless of the room temperature.
That is, the panel surface temperature is not uniform, and it is difficult to measure the minimum temperature in the surface because it is not known where the minimum temperature is on the panel, and humidity sensors that measure indoor humidity generally have a lifetime. Is not suitable for use in air conditioners that are assumed to be used for more than 10 years.
JP 2001-355894 A

  The present invention has been proposed in view of the above-described problems of the prior art, and it is possible to prevent condensation of the radiant panel when cooling the room to be air-conditioned by supplying cold water from the refrigeration apparatus to the radiant panel. It aims at providing the radiation cooling system which can be performed, and its control method.

  The radiant cooling system of the present invention includes a radiant panel (12, 13) arranged in a space to be air-conditioned (for example, a living room 11), a refrigeration apparatus (chiller 500) that generates cold water, and a radiant panel (floor). 12 and ceiling 13) and a chilled water line (Lw) for circulating chilled water between the refrigeration apparatus (500), and the above (air conditioning is performed by the cold heat radiated from the radiation panels (12, 13). In a radiant cooling system that cools the space (11), the temperature measuring device (Str) that measures the temperature of the space to be air-conditioned, and the temperature of the cold water supplied from the refrigeration system (chiller 500) (panel inlet temperature) ) And a control device (control unit 60), and the control device (control unit 60) sets the humidity of the space (11) to be air-conditioned to a predetermined level. A dew point temperature determining unit (61) for determining the dew point temperature of the space to be air-conditioned from the air temperature measured by the temperature measuring device (Str) assuming humidity (for example, relative humidity is 95% RH). Measured by a threshold value determination unit (62) that determines a temperature higher than the dew point temperature by a predetermined temperature (α: for example, 1 ° C. to 3 ° C.) as a threshold value, and the determined threshold value and the water temperature measurement device (Stw). The comparison unit (63) for comparing the temperature of the cold water supplied from the refrigeration apparatus (chiller 500) (panel inlet temperature) and the refrigeration apparatus (chiller 50) based on the comparison result of the comparison unit (63). The refrigeration apparatus control signal generation unit (chiller control signal generation unit 65) that generates the control signal is provided (FIGS. 1 to 3).

  The control method of the radiant cooling system of the present invention for controlling the radiant cooling system (FIGS. 1 to 3) includes an air temperature measuring step (S1) for measuring the temperature of the space (11) to be air-conditioned, Water temperature measurement step (S2) for measuring the temperature of the cold water supplied from the machine 50) (panel inlet temperature), and the humidity of the space (11) to be air-conditioned is a predetermined humidity (for example, relative humidity is 95% RH) A dew point temperature determining step (S3) for determining the dew point temperature of the space (11) to be air-conditioned from the measured air temperature, and a predetermined temperature (α: for example, 1 ° C. to 3 ° C.) from the determined dew point temperature A threshold value determination step (S4) for determining a temperature higher by [° C.] as a threshold value, and the temperature of the cold water supplied from the refrigeration apparatus (chiller 500) measured by the determined threshold value and the water temperature measuring device (Stw) (panel) Compare with inlet temperature) And a control signal to the refrigeration system (chiller 500) is generated (S7) based on the comparison result of the comparison step (S5) (FIG. 1 to FIG. 1). 3).

  In the radiant cooling system of the present invention, the temperature difference (β: eg, 5 ° C. to 10 ° C.) between the water temperature of the cold water flowing into the radiant panel (12, 13) and the surface temperature of the radiant panel (12, 13) is preliminarily determined. If it is known, the threshold value calculation unit (62) determines the temperature from a temperature higher than the dew point temperature determined by the dew point temperature determination unit (61) by a predetermined temperature (α: for example, 1 ° C. to 3 ° C.). It is preferable that the temperature is determined by subtracting the temperature difference (temperature difference β between the temperature of the cold water flowing into the radiation panels 12 and 13 and the surface temperature of the radiation panel) as a threshold (FIG. 4).

  In the control method of such a radiation cooling system (FIG. 4), in the threshold value determination step (S14), a predetermined temperature (α: for example, 1 ° C. to 3 ° C.) than the dew point temperature determined by the dew point temperature determination unit (61). The temperature obtained by subtracting the temperature difference (β) between the temperature of the cold water flowing into the radiation panel (12, 13) and the surface temperature of the radiation panel (12, 13) from the temperature higher by [° C.] is preferably determined as the threshold value. (FIG. 4).

  In carrying out the present invention, a heat pump system using carbon dioxide as a refrigerant, a chilled / hot water line (Lw) communicating with the cooling / heating load side, a hot water storage tank (1) for storing hot water, and carbon dioxide as a refrigerant circulate. A circulation system (heat source unit 50) that compresses the low-pressure gas-phase refrigerant and discharges it as a high-pressure refrigerant in a supercritical state, and a compressor (2 A first heat exchanger (water-cooled gas cooler 3, cooling device) for exchanging heat between the supercritical high-pressure refrigerant discharged from the tank and water flowing through a line (Lt) communicating with the hot water storage tank (1); The third heat exchange that exchanges heat between the second heat exchanger (air-cooled gas cooler 4) that exchanges heat between the refrigerant and the atmosphere and the cold and hot water flowing through the refrigerant and the cold and hot water line (Lw). (Cooling evaporator 5) and second heat exchange 4th heat exchanger which performs heat exchange between the refrigerant | coolant which went to the 3rd heat exchanger (5) from a heat exchanger (4), and the refrigerant | coolant after heat-exchanged by the 3rd heat exchanger (5) (Auxiliary gas cooler 6), the discharge port (2o) of the compressor (2) and the first heat exchanger (3) communicate with each other, and the fourth heat exchanger (6) passes through the second heat exchanger (6). The second heat exchanger (4) and the third heat exchanger (5) communicate with each other, and the third heat exchanger (5) and the compressor (2 through the fourth heat exchanger (6)). ) Branched from a refrigerant line (Lc2) communicating with the suction port (2i) and a refrigerant line (Lc2) communicating between the discharge port (2o) of the compressor (2) and the first heat exchanger (3). A first bypass line (Lb1) that bypasses the second heat exchanger (4) (and merges with the refrigerant line that connects the second heat exchanger 4 and the third heat exchanger 5). The second heat exchanger (4) The refrigerant is branched from the refrigerant line (Lc6) communicating with the third heat exchanger (5), and bypasses the fourth heat exchanger (6) (the second heat exchanger 4 and the third heat exchanger). And a second bypass line (Lb2) that joins the refrigerant line Lc9 that communicates with the refrigerant line Lc9, and the cold / hot water line (Lw) is a hot water storage tank (1) or a third heat exchanger (5). It is preferably used in combination with a heat pump system that is configured to selectively communicate with the heat pump system (FIG. 5).

  Alternatively, it is a heat pump system using carbon dioxide as a refrigerant, a chilled / hot water line (Lw) communicating with the heating / cooling load side, a hot water storage tank (1) for storing hot water, and a circulation system in which carbon dioxide as a refrigerant circulates ( A heat source unit 50), and the circulation system (50) compresses the low-pressure gas-phase refrigerant and discharges it as a high-pressure refrigerant in a supercritical state, and the super-system discharged from the compressor (2). A first heat exchanger (water-cooled gas cooler 3, cooling device) that exchanges heat between the high-pressure refrigerant in a critical state and water flowing through a line (Lt) communicating with the hot water storage tank (1), and the refrigerant and the atmosphere A third heat exchanger (cooling evaporator 5) that performs heat exchange between the second heat exchanger (air-cooled gas cooler 4) that performs heat exchange between the refrigerant and the cold / hot water flowing through the refrigerant and the cold / hot water line (Lw). ) And the third heat exchange from the second heat exchanger (4) A fourth heat exchanger (auxiliary gas cooler 6) that performs heat exchange between the refrigerant directed to (5) and the cold / hot water flowing through the cold / hot water line (Lw), and the discharge port ( 2o) and the first heat exchanger (3), and the second heat exchanger (4) and the third heat exchanger (5) via the fourth heat exchanger (6). The refrigerant line (Lc12) which communicates the third heat exchanger (5) and the suction port (2i) of the compressor (2), the discharge port (2o) of the compressor (2) and the first The heat exchanger (the refrigerant line (Lc2) communicating with 3 is branched and the second heat exchanger (4) is bypassed (the second heat exchanger 4 and the third heat exchanger 5 are From the first bypass line (Lb1) that joins the refrigerant line Lc6 that communicates with the refrigerant line (Lc6) that communicates the second heat exchanger (4) and the third heat exchanger (5). The second bypass line (Lb2) bypassing the fourth heat exchanger (6) and joining the refrigerant line Lc9 that connects the second heat exchanger 4 and the third heat exchanger 5 The cold / hot water line (Lw) selectively communicates with the hot water storage tank (1) or the third heat exchanger (5) and the return line Lw7 is the fourth heat exchanger (6). ) Is preferably used in combination with a heat pump system arranged so as to communicate with the third heat exchanger (5) (FIG. 6).

  Here, in the heat pump system described above, the circulation system (heat source unit 50) includes a bypass line (Lb4) that bypasses the first heat exchanger (water-cooled gas cooler 3) through a bypass valve (Vb2). The third heat exchanger (cooling evaporator 5) and the fourth heat exchanger (auxiliary gas cooler 6) (in addition to that) are bypassed (Vb3 (FIG. 7), Vb4 (FIG. 8)). It is preferable to have a bypass line (Lb5 (FIG. 7), Lb6 (FIG. 8)) that bypasses the liquid receiver 8 and the cooling expansion valve 9) (FIGS. 7 and 8).

  Alternatively, the fourth heat exchanger (auxiliary gas cooler 6) exchanges heat with the refrigerant from the second heat exchanger (4) to the third heat exchanger (5) and the third heat exchanger (5). In the above-described heat pump system (FIG. 5) using carbon dioxide as a refrigerant for exchanging heat with the refrigerant after being performed, the first bypass line (Lb1) and the second bypass line (Lb2) are omitted. Instead, the third heat exchanger (cooling evaporator 5) and the fourth heat exchanger (auxiliary gas cooler 6) (in addition to the receiver 8 and the bypass valve (Vb3)) are sent. A fourth bypass line (Lb5) that bypasses the cooling expansion valve 9) is provided, and is branched from the refrigerant line (Lc10) that communicates the third heat exchanger (5) and the fourth heat exchanger (6). Bypass the fourth heat exchanger (6), and with the fourth heat exchanger (6) Inlet of compressor (2) (2i) and preferably provided with a line that communicates (Lc11) Fifth bypass line merges with the (LB10) (Figure 9).

According to the present invention having the above-described configuration, the temperature of the chilled water (panel inlet temperature) supplied from the refrigeration apparatus (chiller 500) is higher than the threshold value, that is, the dew point temperature determined from the temperature of the space to be conditioned. The temperature difference (β: radiation) from a temperature that is higher by a predetermined temperature (α: 1 ° C. to 3 ° C.) or higher than a determined dew point temperature by a predetermined temperature (α: 1 ° C. to 3 ° C.), for example. If the temperature is lower than the temperature obtained by subtracting the temperature of the cold water flowing into the panel and the surface temperature of the radiant panel (12, 13), the surface of the radiant panel (12, 13) may condense. The water temperature (panel inlet temperature) supplied from the refrigeration apparatus (chiller 500) is increased.
As a result, the surface temperature of the radiant panel (12, 13) becomes higher than the dew point temperature, and the risk of condensation is eliminated.

According to the radiation cooling system of the present invention, it is possible to prevent condensation on the radiation panels (12, 13) without using a humidity sensor.
That is, sensors used for dew condensation prevention control can be substituted by the indoor air temperature sensor (Str) and the water temperature sensor (Stw). The indoor air temperature sensor (Str) can be built in the remote controller (70) of the air conditioner, and the water temperature sensor (Stw) can be built in the chilled water machine 500. Thus, there is no need to arrange the sensor or route the lead wire of the sensor.
That is, in the prior art, it was necessary to attach the panel surface temperature sensor to the panel surface at the construction site and route the lead wire to the microcomputer in the chiller. However, according to the radiant cooling system of the present invention, such a complicated operation is required. Free from hard work.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

First, based on FIG. 1, the structure of the radiation cooling system of embodiment is demonstrated.
In FIG. 1, the radiant cooling system according to the embodiment of the present invention can circulate a cooling load 40, a refrigeration apparatus (a chiller; hereinafter referred to as a chiller) 500, a cooling load 40 and a chiller 500. And a cold water line Lw through which cold water flows.

  The cooling load side 40 includes a floor radiation panel 12, a ceiling radiation panel 13, an indoor temperature sensor Str, and a system operation remote controller 70 installed in the room 11 of the house 10. In the illustrated example, the indoor temperature sensor Str is built in the remote controller 70, and is connected to a control unit 60, which will be described later, through a signal line Li1.

  The chiller 500 includes a refrigeration cycle unit 80, a control unit 60, and a water temperature sensor Stw for measuring the temperature of the chilled water outlet, which is interposed in the vicinity of the refrigeration cycle unit 80 outlet of the chilled water line Lw.

The refrigeration cycle unit 80 includes a heat source unit 50, a hot water storage tank 1, and a hot water storage line Lt in an apparatus represented by a heat pump system using carbon dioxide as a refrigerant, which will be described later, for example (FIGS. 5 to 8). reference).

The chilled water line Lw includes chilled water pipes Lw31 and Lw32 that connect the gathering portion Bw on the forward path side (cold water going) and an inflow port (not shown) of the floor radiant panel 12 and an inflow port (not shown) of the ceiling radiant panel 13; There are provided cold water pipes Lw41 and Lw42 that connect the gathering portion Gw of (cold water return) and a discharge port (not shown) of the floor radiation panel 12 and a discharge port (not shown) of the ceiling radiation panel 13.

In the chilled water line Lw, one end of the (returned) chilled water pipe Lw5 is connected to the refrigeration cycle unit 80 side of the return path side gathering part Gw, and the other end of the chilled water pipe Lw5 is, for example, the refrigeration cycle unit 80 (not shown). It is connected to the inlet side of the refrigerant evaporator (see FIG. 5).
On the other hand, one end of a chilled water pipe Lw2 through which chilled water cooled by the refrigerant evaporator flows is connected to the refrigeration cycle unit 80 side of the gathering part Bw on the forward path side, and the other end of the chilled water pipe Lw2 is connected to the refrigeration cycle. It is connected to the unit 80 (the outlet side of the refrigerant evaporator (not shown)).

In the chilled water line Lw, a water temperature gauge Stw is interposed in the vicinity of the outlet side of the refrigeration cycle unit 80 of the (forward) chilled water pipe Lw2, and the temperature of the chilled water flowing through the pipe is constantly measured, and the information is obtained. The signal is transmitted to the control unit 60 through the signal line Si2.
Although not shown, the (returned) cold / hot water pipe Lw5 is provided with a cold water circulation pump that circulates cold water, which is omitted in FIG.

On-off valves V31 and V32 are interposed in the cold water pipes Lw31 and Lw32, respectively.

Next, the configuration of the control unit 60 will be described with reference to FIG.
In FIG. 2, the control unit 60 includes a dew point temperature determination unit 61, a threshold value calculation unit 62, a comparison unit 63, a determination unit 64, and a chiller control signal generation unit 65.

  The dew point temperature determination unit 61 calculates the dew point temperature when the relative humidity is 95% based on the information from the room temperature sensor Str.

The threshold value calculation unit 62 is
A value obtained by adding a constant α to the dew point temperature determined by the dew point temperature determination unit 61 is determined as a threshold value.
That is,
Threshold = dew point temperature + α
Or
A value obtained by adding a constant α to the dew point temperature and further subtracting a predetermined value β therefrom is determined as a threshold value.
That is,
Threshold = dew point temperature + α-β
Here, specific values of α and β will be described in detail in the description of the control method described later.

The comparison unit 63 determines whether or not the “panel inlet water temperature” is equal to or higher than the “threshold value”, that is, “dew point temperature + α” or “dew point temperature + α−β” based on the measurement result of the water temperature sensor Stw. To compare.

The determination unit 64 determines how to operate the chilled water machine 50 (dehumidify or not dehumidify) based on the comparison result output by the comparison unit 63.

The chiller control signal generation unit 65 starts a control signal (dehumidify, not dehumidify) to the chiller 50 side according to the determination made by the determination unit.

Next, the control method of the cold water machine in the embodiment will be described based on FIG.
First, the room temperature is measured by the room temperature sensor Str installed in the living room 11 (step S1), the water temperature at the panel entrance is measured by the water temperature sensor Stw (step S2), and then the dew point temperature determination unit 61 determines the dew point temperature. (Step S3).

Here, the dew point temperature is calculated on the assumption that the humidity is 95%, which is so-called “worst assumption” (95% is the same humidity as “the back of the cocoon in June”).
Usually, such high humidity does not occur. Computation of the dew point temperature at a high humidity of 95% is regarded as a kind of “safety factor” (the actual indoor humidity is lower, so no condensation occurs even at a dew point temperature of 95% humidity).

When the location where the temperature is measured is separated from the surface of the radiation panel, the temperature at the location and the panel surface temperature may be different. By calculating the dew point temperature at a high humidity of 95%, it corresponds to the case where such a problem (problem that the temperature at the measurement location is different from the panel surface temperature) occurs. That is, if the dew point temperature is calculated at a high humidity of 95% (high humidity that is not possible in an actual room), the calculated dew point temperature is higher than the actual dew point temperature. Even if the temperature is higher than the panel surface temperature (by calculating the dew point temperature to be higher than the actual temperature), it is canceled out, and there is no problem in the determination described later.

There is no place in the panel surface where the temperature is lower than the panel inlet water temperature. Therefore, if the panel entrance temperature is lower than the dew point temperature, no dew condensation occurs on the panel surface.

In the next step S4, the threshold value calculation unit 62 calculates a threshold value, that is, “dew point temperature + α”.
Here, α is a kind of safety coefficient, for example, 1 ° C. to 3 ° C. is used.
Even if α is zero, there is almost no possibility of condensation for the following reasons.
Reason: The panel surface temperature is 5 ° C. to 10 ° C. higher than the panel inlet water temperature (β; this β range is used in the modification example of the embodiment), so the panel surface is higher than the dew point temperature even when α is zero. Will be 5-10 degreeC high.

In addition to this, the panel is prevented from dew condensation during cooling use by allowing for safety of only α (1 ° C. to 3 ° C.).

In the next step S5, the determination unit 64 determines whether or not the panel inlet water temperature is equal to or higher than a threshold value, that is, whether or not the dew point temperature is equal to or higher than α.
If the panel inlet water temperature is equal to or higher than the dew point temperature + α (YES in step S5), there is no need for dew condensation, so the cooling is continued as it is (no dehumidification; step S6), and then the process proceeds to step S8.

On the other hand, when the panel inlet water temperature is lower than the dew point temperature + α (NO in step S5), it is determined that there is a possibility of condensation, and dehumidification is performed so that the panel inlet temperature becomes the dew point temperature + α or more. In order to make the function work, the chiller side is controlled (step S7), and the process proceeds to step S8.

  In step S8, the control unit 60 determines whether or not to end the control. If the control unit 60 is to end (YES in step S8), the control unit 60 ends as it is, and if the operation is continued, the control unit 60 returns to step S1. Step S1 and subsequent steps are repeated again.

Next, FIG. 4 shows a modification of the embodiment (in other words, FIG. 4 is a flowchart showing the control of the modification in the embodiment described in FIGS. 1 to 3).
The control shown in FIG. 3 shows the control when the temperature difference β between the water temperature flowing into the panel and the panel surface temperature is unknown.

If the temperature difference β between the water temperature flowing into the panel and the panel surface temperature is known, condensation does not occur unless the water temperature flowing into the panel is lower than the indoor dew point temperature by β.
That is,
Panel inlet water temperature = dew point temperature + α-β
here,
β is, for example, 5 ° C. to 10 ° C.
The control flow chart of FIG. 4 shows a method for controlling the operation when dehumidification is necessary / unnecessary and when dehumidification is necessary under such conditions.
That is, the only difference between the control in FIG. 3 and the control in FIG. 4 is whether the threshold is regarded as “dew point temperature + α” or “dew point temperature + α−β”.
The water temperature flowing into the panel is expected to be slightly higher than the panel inlet water temperature, but the temperature difference (temperature difference between the water temperature flowing into the panel and the panel inlet water temperature) also causes condensation. It becomes a kind of safety factor for not.

  In the present invention, the refrigeration apparatus is preferably used in combination with, for example, a heat pump system using carbon dioxide as a refrigerant.

An example of such a heat pump system is the system shown in FIG. In FIG. 5, lines Lw and Ld connecting the respective units including the portion 50 (heat source unit), the hot water tank 1, and the radiation panels 12 and 13 are the refrigeration apparatus (cold water machine; reference numeral 500 in FIG. 1). It corresponds to.
Hereinafter, an example of a heat pump system using carbon dioxide as a refrigerant will be described with reference to FIG.

In FIG. 5, the carbon dioxide heat pump air conditioning system (CO2 heat pump air conditioning system) includes an air conditioning load side 40, a circulation system (heat source unit: hereinafter referred to as a heat source unit) 50, and a hot water storage tank 1 as large units. It consists of and.

For example, the air conditioning load side 40 has a floor radiation panel 12 stretched on the floor of the living room 11 of the house 10 and a ceiling radiation panel 13 stretched on the ceiling. . Water temperature sensors St <b> 1 and St <b> 2 are interposed on the inlet side of the cold / hot water line Lw described later of the floor radiation panel 12 and the ceiling radiation panel 13.
Here, the radiant panel refers to a panel provided on the ceiling and floor in order to give heat or cold to the room, and is referred to as a “radiant panel” because the heat or cold is input in the form of “radiation”.
The radiation panel has the following advantages.
In the case of cooling, cooling is possible even if the temperature of the chilled water is somewhat high. Specifically, cooling is possible even when the chilled water temperature is about 13 ° C. (normally the chilled water temperature is 7 ° C.).
Since it is a panel, a large area can be cooled or heated simultaneously.

The heat source unit 50 includes a compressor 2, a first heat exchanger (water-cooled gas cooler: hereinafter, the first heat exchanger is referred to as a water-cooled gas cooler) 3, and a second heat exchanger (air-cooled gas cooler: hereinafter, the first 2 is called an air-cooled gas cooler) 4, a third heat exchanger (cooling evaporator: hereinafter, the third heat exchanger is called cooling evaporator) 5, and a fourth heat exchanger ( Auxiliary gas cooler: hereinafter, the fourth heat exchanger is referred to as an auxiliary gas cooler) 6, and these units are connected to be circulated, and a refrigerant line Lc in which carbon dioxide (CO 2) as a refrigerant circulates is formed. ing. Here, the air-cooled gas cooler 4 may function as an air-cooled gas cooler or may function as an evaporator.

The refrigerant line Lc is configured by the following piping. The outlet 2o of the compressor 2 and the water-cooled gas cooler 3 are connected by a refrigerant pipe Lc1. The water-cooled gas cooler 3 and the air-cooled gas cooler 4 are connected from the water-cooled gas cooler side to the refrigerant pipe Lc2, the first three-way valve Vc1, the refrigerant pipe Lc3, the first branch point B1, the refrigerant pipe Lc4, the second branch point B2, and the refrigerant pipe Lc5. It communicates with.

An expansion valve 7 is interposed in the refrigerant pipe Lc4. Further, the first and second branch points B1 and B2 are communicated with each other by a bypass Lb3 having an on-off valve Vb1 interposed therebetween.

The air-cooled gas cooler 4 and the refrigerant evaporator 5 pass through the auxiliary gas cooler 6 between them, and from the air-cooled gas cooler 4 side, the refrigerant pipe Lc5, the third branch point B3, the refrigerant pipe Lc6, the second three-way valve Vc2, and the refrigerant The pipe Lc7, the auxiliary gas cooler 6, the refrigerant pipe Lc8, the fourth branch point B4, and the refrigerant pipe Lc9 communicate with each other.

The first three-way valve Vc1 and the third branch point B3 are connected by a first bypass Lb1 so as to bypass the air-cooled gas cooler 4.
The second three-way valve Vb2 and the fourth branch point B4 are connected by a second bypass Lb2 so as to bypass the auxiliary gas cooler 6.

The pipe Lc9 includes a liquid receiver (receiver tank configured to ensure that the liquid-phase refrigerant reaches the expansion valve 9) 8 and the expansion valve 9 from the fourth branch point B4 toward the refrigerant evaporator 5. It is intervened.

The refrigerant evaporator 5 and the auxiliary gas cooler 6 are connected by a pipe Lc10. The auxiliary gas cooler 6 and the inlet 2i of the compressor 2 are connected by a pipe Lc11.
Thus, each unit communicates with the pipings Lc1 to Lc11 so as to be circulated.

The refrigerant evaporator 5 of the heat source unit 50 communicates with the floor radiant panel 12 and the ceiling radiant panel 13 on the air conditioning load side 40 so that cold / hot water can be circulated by the cold / hot water line Lw, and flows through the refrigerant line Lc. It is configured to exchange heat with the excess refrigerant (high-pressure CO2).

Although the description of the cold / hot water line Lw partially overlaps, the hot / cold water pipes Lw31 and Lw32 connecting the gathering part Bw and the inlet (not shown) of the floor radiant panel 12 and the inlet (not shown) of the ceiling radiant panel 13 are gathered. It has the part Gw and the cold / hot water pipes Lw41 and Lw42 which connect the discharge port (not shown) of the radiation panel 12 for floors, and the discharge port (not shown) of the radiation panel 13 for ceiling. A cold / hot water pipe Lw5 interposing a cold / hot water pump P2 is connected to the gathering part Gw, and the refrigerant evaporator 5 of the heat source unit 50 is reached via the three-way valve Vw1 and the cold / hot water pipe Lw6. Then, after exchanging heat with the refrigerant (CO2) circulating in the circulatory system Lc, the refrigerant is connected to the collecting part Bw via the cold / hot water pipe Lw1, the three-way valve Vw2, and the cold / hot water pipe Lw2.

On-off valves V31 and V32 are interposed in the cold / hot water pipes Lw31 and Lw32, respectively.

The hot water storage tank 1 is connected so that water (or hot water) can be circulated by a hot water storage line Lt composed of a water-cooled gas cooler 3 of the heat source unit 50, a return hot water pipe Lt1, and a hot water storage pipe Lt2 interposed with a hot water storage pump P1. Has been.

A hot water (tap water) line La1 is connected to the bottom of the hot water storage tank 1, and a hot water supply line La2 is connected to the upper part of the hot water storage tank 1.

The hot / cold water line Lw and the hot water storage tank 1 are connected by a hot water line Ld so that hot water can circulate between the cold / hot water line Lw and the hot water storage tank 1. That is, the first connection port 1a of the hot water storage tank 1 and the three-way valve Vw1 on the cold / hot water line Lw side are connected by the hot water pipe Ld1 of the hot water line Ld, and the second connection port 1b of the hot water storage tank 1 and the cold / hot water line Lw side. The three-way valve Vw2 is connected by a hot water pipe Ld2 of the hot water line Ld.

In the refrigerant line Lc, in the water-cooled gas cooler 3 which is the first heat exchanger, the supercritical high-pressure refrigerant (CO2) discharged from the compressor 2 and the water flowing through the line Lt communicating with the hot water storage tank 1 are used. Then, in the air-cooled gas cooler 4 that is the second heat exchanger, heat is exchanged between the refrigerant (CO2) and the atmosphere, and further, the cooling evaporator 5 that is the third heat exchanger. , Heat exchange is performed between the refrigerant and the cold / hot water flowing through the cold / hot water line Lw.

The refrigerant that has exited the cooling evaporator 5 exchanges heat with the refrigerant from the air-cooled gas cooler 4 toward the cooling evaporator 5 in the auxiliary gas cooler 6 that is the fourth heat exchanger, and then is returned to the compressor 2.

The cold / hot water line Lw is configured to selectively communicate with the hot water storage tank 1 or the cooling evaporator 5.
The air-conditioning apparatus of FIG. 1 is configured as described above, and switches the on-off valve (electromagnetic valve) Vb1 or the three-way valves Vc1 and Vc2 as appropriate, and is connected to the hot water storage tank 1, the cold / hot water line Lw, and the cold / hot water line Lw. By combining with the cold / hot water circulation pump P2, the three-way valves Vw1 and Vw2 and the radiation panels 12 and 13 provided as air conditioning loads as appropriate, “cooling single operation”, “only hot water operation”, “cooling and hot water storage operation” "," Heating and hot water storage operation "can be switched freely.

In such a heat pump system, the hot water storage pump P1 is stopped to stop the flow of water in the line Lt communicating with the hot water storage tank 1, and the high-pressure refrigerant discharged from the compressor 2 is supplied to the air-cooled gas cooler 4 by the outside air. After cooling and the refrigerant cooled by the air-cooled gas cooler 4 is further cooled by the auxiliary gas cooler 6, the cooling evaporator 5 may exchange heat with cold water.
By stopping the flow of water in the line Lt communicating with the hot water storage tank 1, the high-pressure refrigerant passes through the water-cooled gas cooler 3, so that the amount of heat held by the high-pressure refrigerant in the water-cooled gas cooler 3 is transferred to the hot water storage tank 1 side. It will never be thrown in. As a result, it is possible to prevent a situation where the hot water supply operation is performed even though there is no hot water supply demand.

  The high-pressure refrigerant discharged from the compressor 2 is cooled by the outside air in the air-cooled gas cooler 4, and the refrigerant cooled in the air-cooled gas cooler 4 is further cooled by the auxiliary gas cooler 6, and then the cooling evaporator 5 is used. Even when the temperature exceeds 31.1 ° C. and the refrigerant has not been cooled to the liquid phase completely in the air-cooled gas cooler 4, after the heat exchange is performed in the cooling evaporator 5 by the auxiliary gas cooler 6. Since the cooling is further performed using the refrigerant, the refrigerant is in a liquid phase when the auxiliary gas cooler 6 is discharged. As a result, even when the outside air temperature exceeds 31.1 ° C., a sufficient cooling capacity can be obtained without performing a hot water supply operation.

  Alternatively, as the refrigeration apparatus used in the present invention, a heat pump system as shown in FIG. 6 is also preferable.

The carbon dioxide heat pump air-conditioning system (CO2 heat pump air-conditioning system) in FIG. 6 has a communication relationship between the refrigerant circulating line Lc and the cold / hot water line Lw in the auxiliary gas cooler 6 and the evaporator 5 with respect to the system in FIG. Is changing.
That is, in FIG. 6, the cold / hot water return line communicates with the auxiliary gas cooler 6 and then returns to the evaporator 5. The refrigerant line Lc communicates directly from the evaporator 5 to the suction side 2 i of the compressor 2.

That is, in the cold / hot water line Lw, after the return side three-way valve Vw1, the cold / hot water pipe Lw7 communicates directly with the auxiliary gas cooler 6, and then returns to the evaporator 5 via the cold / hot water pipe Lw8.

On the other hand, after leaving the evaporator 5, the refrigerant line Lc communicates directly with the suction side 2 i of the compressor 2 through the pipe Lc 12.
Others are the same as the system of FIG.

Also in the system of FIG. 6, as in FIG. 5, “cooling single operation”, “only hot water operation”, “cooling and hot water storage operation”, and “heating and hot water storage operation” can be freely switched.

  In such a heat pump system, the flow of water in the line Lt communicating with the hot water storage tank 1 is stopped, and the high-pressure refrigerant discharged from the compressor 2 is “passed through” the water-cooled gas cooler 3 and then supplied to the air-cooled gas cooler 4. Then, after cooling with the outside air and further cooling the refrigerant cooled by the air cooling gas cooler 4 with the auxiliary gas cooler 6, the cooling evaporator 5 can exchange heat with the cold water, whereby the cooling only operation can be performed.

If the hot water storage pump P1 is stopped to stop the flow of water in the line Lt communicating with the hot water storage tank 1, the amount of heat held by the high-pressure refrigerant will not be input to the hot water storage tank 1 side by the water-cooled gas cooler 3, and hot water supply demand It is possible to prevent a situation in which the hot water supply operation is performed even though there is not.
Even when the outside air temperature exceeds 31.1 ° C. and the refrigerant is not cooled to the extent that it is completely in the liquid phase in the air-cooled gas cooler 4, the auxiliary gas cooler 6 opens the return line Lw 7 of the cold / hot water line Lw. Since it is further cooled using the flowing cold water, the refrigerant cooled by the air-cooled gas cooler 4 becomes a liquid phase at the stage where heat exchange with the cold water is completed by the auxiliary gas cooler 6, and sufficient cooling capacity can be obtained.

  Here, in each of the two types of heat pump systems described above, the cold / hot water circulation pump P2 is stopped to stop the cold / hot water circulation in the cold / hot water line Lw, and the refrigerant makes the refrigerant evaporator 5 and the auxiliary gas cooler 6 “ If it is configured to “pass through,” only hot water storage can be performed.

  In addition, the cold / hot water line Lw is connected to the refrigerant evaporator 5 side, and the refrigerant that has passed through the water-cooled gas cooler 3 is caused to flow down to the first bypass line Lb1 and the second bypass line Lb2, and the air-cooled gas cooler 4 and the auxiliary gas cooler. If 6 is bypassed and communicated with the refrigerant evaporator 5, hot water storage and cooling operations are performed.

  Furthermore, when performing hot water storage and heating operation in the two heat pump systems described above, the hot / cold water line Lw is connected to the hot water storage tank 1 side from the state of operation of only the hot water storage described above, and the hot water in the hot water storage tank 1 is cooled / cooled. What is necessary is just to circulate in the water line Lw and to supply to the heating load side 40.

  In the two heat pump systems described above, for example, as shown in FIGS. 7 and 8, a bypass line Lb4 through which a bypass valve Vb2 is passed to bypass the water-cooled gas cooler 3, and bypass valves (Vb3 (FIG. 7), Vb4 ( FIG. 8)) is bypassed and bypass lines (Lb5 (FIG. 7), Lb6 (FIG. 8)) bypassing the cooling evaporator 5 and the auxiliary gas cooler 6 (in addition, the receiver 8 and the cooling expansion valve 9). And may be provided.

  Alternatively, as a second modification of the heat pump system shown in FIG. 5, the heat pump system of FIG. 5, that is, the auxiliary gas cooler 6 (fourth heat exchanger) is changed from the second heat exchanger 4 to the third heat exchanger 5. In the heat pump system for exchanging heat between the refrigerant facing the refrigerant and the refrigerant after the heat exchange with the third heat exchanger 5, the first bypass line Lb1 and the second bypass line Lb2 are omitted, Instead, a fourth bypass line Lb5 and a fifth bypass line Lb10 may be provided.

Here, a bypass valve Vb3 is sent to the fourth bypass line Lb5, and the cooling evaporator 5 (third heat exchanger) and the auxiliary gas cooler 6 (fourth heat exchanger) (in addition to them) The liquid receiver 8 and the cooling expansion valve 9) are bypassed.
Further, the fifth bypass line Lb10 branches from the refrigerant line Lc10 that communicates the third heat exchanger 5 and the fourth heat exchanger 6, bypasses the fourth heat exchanger 6, and It merges with Lc11. The line Lc11 communicates the fourth heat exchanger 6 and the suction port 2i of the compressor 2.

In the heat pump system of FIG. 9, similarly to the system of FIG. 5, “cooling single operation”, “only hot water operation”, “cooling and hot water storage operation”, and “heating and hot water storage operation” can be freely switched.
In other words, if the flow of water in the line Lt communicating with the hot water storage tank 1 is stopped and the fourth bypass line Lb5 and the fifth bypass line Lb10 are closed, the high-pressure refrigerant discharged from the compressor 2 causes the water-cooled gas cooler 3 to flow. After being “passed through”, it is cooled by the outside air in the air-cooled gas cooler 4 and further cooled by the auxiliary gas cooler 6, and is then heat-exchanged with cold water by the cooling evaporator 5, so that the cooling single operation can be performed.

The pump P1 is operated to flow water to the line Lt communicating with the hot water storage tank 1, the cold / hot water circulation pump P2 is stopped, the cold / hot water circulation in the cold / hot water line Lw is stopped, and the bypass valve Vb3 is opened. If the refrigerant evaporator 5 and the auxiliary gas cooler 6 are bypassed by the bypass line Lb5, the operation of only hot water storage can be performed.
And if the cold / hot water line Lw is connected to the hot water storage tank 1 via lines Ld1 and Ld2, heating and hot water storage operation are possible.

  And if the port connected to the auxiliary gas cooler 6 of the three-way valve Vc10 is closed, the bypass line Lb10 is opened, and the bypass valve Vb3 is closed, hot water storage and cooling operation are performed.

  It should be noted that the illustrated embodiment is merely an example and is not intended to limit the technical scope of the present invention.

The block diagram which showed the structure of the carbon dioxide heat pump air conditioning system of embodiment of this invention. The block diagram which showed the structure of the control unit in embodiment. The control flowchart which showed the control method in embodiment. The control flowchart which showed the control method at the time of changing a threshold value with respect to the flowchart of FIG. The block diagram of the heat pump system which uses a carbon dioxide as a refrigerant | coolant for demonstrating the structure of the 1st Example of the freezing apparatus (cold water machine) used in combination with embodiment of this invention. The block diagram of the heat pump system which uses a carbon dioxide as a refrigerant | coolant for demonstrating the structure of the 2nd Example of the freezing apparatus (cold water machine) used in combination with embodiment of this invention. The block diagram which showed the modification of the heat pump system of FIG. The block diagram which showed the modification of the heat pump system of FIG. The block diagram which showed the 2nd modification of the heat pump system of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Hot water tank 2 ... Compressor 3 ... 1st heat exchanger / water-cooled gas cooler 4 ... 2nd heat exchanger / air-cooled heat exchanger 5 ... 3rd heat exchanger / Cooling evaporator 6 ... fourth heat exchanger / auxiliary gas coolers 7, 9 ... expansion valve 8 ... receiver 40 ... air conditioning load 50 ... circulation system / heat source unit 60 ... Control unit 61 ... dew point temperature determination unit 62 ... threshold calculation unit 63 ... comparison unit 64 ... judgment unit 65 ... chiller control signal generation unit 500 ... refrigeration system / chiller Ld ... Hot water line Lt ... Hot water storage line Lw ... Cold and hot water line P1 ... Hot water storage pump P2 ... Circulation pump Str ... Indoor temperature sensor Stw ... Water temperature sensor Vb1 ... On-off valve Vc1 , Vc2 ... three-way valve Vw1, Vw2 ... three Valve

Claims (4)

  A radiant panel arranged in a space to be air-conditioned, a refrigeration apparatus that generates cold water, and a chilled water line for circulating the chilled water between the radiant panel and the refrigeration apparatus, and radiated cold heat from the radiant panel In the radiant cooling system for cooling the space, the air temperature measuring device for measuring the temperature of the space to be air-conditioned, the water temperature measuring device for measuring the temperature of the cold water supplied from the refrigeration device, and a control device, The control device includes a dew point temperature determination unit that determines the dew point temperature of the space to be air-conditioned from the air temperature measured by the temperature measuring device assuming a predetermined humidity as the humidity of the space to be air-conditioned, and the determined dew point A threshold value determination unit that determines a temperature higher than the temperature by a predetermined temperature as a threshold value, and the determined threshold value and the water temperature of the cold water supplied from the refrigeration apparatus measured by the water temperature measurement device. A comparing unit for compare, radiant cooling system characterized in that it has a refrigerating apparatus control signal generating unit for generating a control signal to the refrigerating apparatus on the basis of a comparison result of the comparison unit.   The threshold value calculation unit uses, as a threshold value, a temperature obtained by subtracting a temperature difference between the temperature of the cold water flowing into the radiant panel and the surface temperature of the radiant panel from a temperature higher than the dew point temperature determined by the dew point temperature determining unit by a predetermined temperature. The radiant cooling system of claim 1, configured to determine.   The control method for controlling the radiation cooling system according to claim 1, wherein an air temperature measurement step for measuring an air temperature of a space to be air-conditioned, a water temperature measurement step for measuring a water temperature of cold water supplied from the refrigeration apparatus, and air conditioning should be performed. A dew point temperature determining step for determining the dew point temperature of the space to be air-conditioned from the air temperature measured assuming the predetermined humidity, and a threshold temperature that is higher than the determined dew point temperature by a predetermined temperature A threshold value determination step, and a comparison step of comparing the determined threshold value with the temperature of the cold water supplied from the refrigeration device measured by the water temperature measurement device, and to the refrigeration device based on the comparison result of the comparison step A control method for a radiant cooling system, characterized in that a control signal is generated.   In the threshold value determining step, a temperature obtained by subtracting a temperature difference between the temperature of the cold water flowing into the radiant panel and the surface temperature of the radiant panel from a temperature higher than the dew point temperature determined by the dew point temperature determining unit by a predetermined temperature is used as a threshold value. The method of controlling a radiation cooling system according to claim 3, wherein the control method is determined.

Images