PH12016000166B1

PH12016000166B1 - Air conditioning system

Info

Publication number: PH12016000166B1
Application number: PH12016000166A
Authority: PH
Inventors: Masahiro Odane
Original assignee: Mitsubishi Electric Building Techno Service Co Ltd
Priority date: 2015-05-13
Filing date: 2016-04-27
Publication date: 2017-12-18
Also published as: PH12016000166A1; CN106152320A; JP6250589B2; JP2016211825A

Abstract

An air conditioning system includes a fan coil unit (10), which includes a coil (11), a fan (12) , a control valve (13), a thermal medium supply pipe (14) , a thermal medium discharge pipe (15), a temperature sensor (17), and a controller (18) for operating the control valve (13), a thermal medium supply apparatus (20), a hot thermal medium feed pipe (22), a hot thermal medium recovery pipe (23), a cold thermal medium feed pipe (26), a cold thermal medium recovery pipe (27), first to fourth shutoff valves 31 to 24, and a control unit (40). When a room temperature TR is lower than a room air temperature set value TS2, the first and second shutoff valves (31, 32) are opened, and the third and fourth shutoff valves (33, 34) are closed. When the room temperature TR is higher than a room air temperature set value TR1, the third and fourth shutoff valves (33, 34) are opened, and the first and second shutoff valves (31, 32) are closed. In this way, the air conditioning system can separately perform cooling or heating based on temperatures for rooms or zones with a simple method.

Description

DESCRIPTION OF THE EMBODIMENTS

In the following, embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, an air conditioning system 100 according to an embodiment of this invention includes a two pipe fan coil unit 10 equipped with a thermal medium supply pipe 14 and a thermal medium discharge pipe 15, a control unit 40 connected through a data bus 41 to a controller 18 in the fan coil unit 10, and a thermal medium supply apparatus 20 composed of a boiler 21 and a freezer 25and configured to supply a hot thermal medium or a cold thermal medium. Although the embodiment in FIG. 1 shows only one fan coil unit 10 installed in each room or each zone, two or more fan coil units 10 may be installed in each room or each zone as in a case of another embodiment described further below.

The thermal medium supply apparatus 20 and the fan coil unit 10 are connected to each other through a hot ; thermal medium feed pipe 22 for feeding a hot thermal medium from the boiler 21 in the thermal medium supply apparatus 20 to the thermal medium supply pipe 14, a hot thermal medium recovery pipe 23 for recovering the hot thermal medium from the thermal medium discharge pipe 15 to the boiler 21 in the thermal medium supply apparatus 20, a cold thermal medium feed pipe 26 for feeding a cold thermal medium from the freezer 25 in the thermal medium supply apparatus 20 to the thermal medium supply pipe 14, and a cold thermal medium recovery pipe 27 for recovering the cold thermal medium

EERE ERE ————— ————————————————————————————————————————peep eg eee eee from the thermal medium discharge pipe 15 to the freezer 25 in the thermal medium supply apparatus 20.

Further, first to fourth shutoff valves 31 to 34 are respectively inserted in the hot thermal medium feed pipe 22, the hot thermal medium recovery pipe 23, the cold thermal medium feed pipe 26, and the cold thermal medium recovery pipe 27. The shutoff valves 31 to 34 are motor-operated valves that are opened and closed by the control unit 40.

As shown in FIG. 1, the fan coil unit 10 includes a coil 11 through which the hot thermal medium whose temperature is higher than a temperature of room air or the cold thermal medium whose temperature is lower than the temperature of room air is made to flow, to exchange heat with room air that is made to flow outside the coil 11, a fan 12 for directing room air to flow outside the coil 11, a control valve 13 for controlling a flow rate of the hot thermal medium or the cold thermal medium flowing through the coil 11, the thermal medium supply pipe 14 for supplying the hot or cold thermal medium into the coil 11, the thermal medium discharge pipe 15 for discharging the hot or cold thermal medium from the coil 11, a temperature sensor 17 for detecting a room air temperature, and the controller 18. The control valve 13 and the fan 12 are connected to the controller 18 and operated in accordance with a command from the controller 18. The temperature sensor 17 is connected to the controller 18, and configured to input data of the detected room temperature into the controller 18. The controller 18 is connected via the data bus 41 to the control unit 40, to allow mutual transmission and receipt of an information value of a room temperature TR detected by the temperature sensor 17 and room temperature set values TS1 and TS2 supplied from a not-illustrated separate apparatus.

The controller 18 has a cooling mode and a heating mode in which the control valve 13 is operated as shown in FIGS. 2 and 3 based on both the room temperature TR detected by the temperature sensor 17 and the room temperature set values TS1l, TS2 received from the control unit 40.

In the cooling mode as shown in FIG. 2, when the room temperature TR detected by the temperature sensor 17 is increased to or above the room temperature set value TS1 (a set value for cooling) received from the control unit 40 (TR 2 TS1l), a valve opening is changed from 0% (fully closed position) to 100% (fully open position) in proportion to the room temperature TR while the room temperature TR lies between the room temperature set value TS1 and a temperature Tl, and is then maintained at 100% (fully open position) after the room temperature TR reaches or exceeds the temperature

Tl. When the room temperature TR detected by the temperature sensor 17 is lower than the room temperature set value TS1 (TR < TS1l), the valve opening is maintained at 0% (fully closed position). In the heating mode as shown in FIG. 3, when the room temperature TR detected by the temperature sensor 17 is decreased to or below the room temperature set value

TS2 (a set value for heating) received from the control unit 40 (TR £ TS2), the valve opening is changed from 0% (fully closed position) to 100% (fully open position) in proportion to the room temperature TR while the room temperature TR lies between the room temperature set value TS2 and a temperature T2, and is then maintained at 100% (fully open position) after the room temperature TR matches or falls below the temperature T2. Meanwhile, when the room temperature

TR detected by the temperature sensor 17 is higher than the room temperature set value TS2 (TR > TS2), the valve opening is maintained at 0% (fully closed position). It should be noted that although any values may be arbitrarily specified to the room temperature set values TS1 and TS2, a temperature differential ATS should be present between the room temperature set value TS1 (the set value for cooling) and the room temperature set value TS2 (the set value for heating) to prevent operation mode hunting. In a range of the temperature differential ATS, the opening of the control valve 13 is maintained at 0% regardless of the operation modes.

Operation of the air conditioning system 100 structured as described above will be explained below.

As described above, the room temperature set values TR1 and TR2 have been input from the not-illustrated separate apparatus into the control unit 40. The room temperature set values TR1 and TR2also have been input through the data bus 41 into the controller 18 of the fan coil unit 10. The room temperature TR detected by the temperature sensor 17 is input into the controller 18, and an information value of the room temperature TR (a room temperature information value) is input through the data bus 41 into the control unit 40.

Here, in a case where a specified room temperature set value is the room temperature set value TS1 (the set value for cooling) shown in FIG. 2, and the room temperature TR detected by the temperature sensor 17 matches or exceeds the room temperature set value TS1 (TR 2 RS1), the control unit 40 causes the controller 18 to operate in the cooling mode. In addition, the control unit 40 closes the first and second shutoff valves 31, 32 and opens the third and fourth shutoff valves 33, 34. This directs the cold thermal medium (cold water) from the freezer 25 to flow in the order of "freezer 25 -> cold thermal medium feed pipe 26 -> third shutoff valve 33 -> thermal medium supply pipe 14 -> control valve 13 -> coil 11 => thermal medium discharge pipe 15 -> fourth shutoff valve 34 -> cold thermal medium recovery pipe 27 -> freezer 25", which cools down the air made to flow outside the coil 11 by the fan 12, and accordingly carries out cooling of the room. Then, the opening of the control valve 13 is increased as the room temperature TR detected by the temperature sensor 17 becomes higher. On the other hand, when the room temperature TR detected by the temperature sensor 17 is decreased to or below the room temperature set value TS1 (the set value for cooling), the control unit 40 keeps the controller 18 operating in the cooling mode.

Then, after the room temperature TR is further decreased to or below the temperature set value TS2 (the set value for heating) (TR £ TS2) shown in FIG. 3, the control unit 40 switches the controller 18 from the cooling mode to the heating mode. In addition, the control unit 40 opens the first and second shutoff valves 31, 32 and closes the third and fourth shutoff valves 33, 34. This directs the hot thermal medium

(hot water) from the boiler 21 to flow in the order of "boiler 21 -> hot thermal medium feed pipe 22 -> first shutoff valve 31 -> thermal medium supply pipe 14 -> control valve 13 -> coil 11 -> thermal medium discharge pipe 15 -> second shutoff valve 32 -> hot thermal medium recovery pipe 23 -> boiler 21", which heats the air made to flow outside the coil 11 by the fan 12, and accordingly carries out heating of the room.

Subsequent to this, the opening of the control valve 13 is increased as the room temperature TR detected by the temperature sensor 17 becomes lower.

Thus, in the air conditioning system 100 according to this embodiment, when the room temperature TR detected by the temperature sensor 17 reaches or exceeds the room temperature set value TS1l (the set value for cooling), the control unit 40 performs control operations of switching the controller 18 to the cooling mode, closing the first and second shutoff valves 31, 32, and opening the third and fourth shutoff valves 33, 34, to thereby direct the cold thermal medium into the coil 11. On the other hand, when the room temperature TR detected by the temperature sensor 17 falls down to the room temperature set value TS2 (the set value for heating) or below, the control unit 40 performs control operations of switching the controller 18 to the heating mode, opening the first and second shutoff valves 31, 32, and closing the third and fourth shutoff valves 33, 34, to thereby direct the hot thermal medium into the coil 11. With this operation of the air conditioning system 100, the operation mode of the controller 18 can be matched with selection of the thermal media to be made to flow into the air conditioning system 100, which can, in turn, facilitate smooth changeover between cooling and heating operations.

In the above, only the operation performed when the room temperature TR is decreasing has been described. Operation performed in a case where the room temperature TR is increasing 1s identical to the above-described operation other than that the heating and cooling modes are replaced with each other, and description related to this case is therefore not repeated.

In the air conditioning system 100 according to the above-described embodiment, operation of the controller 18 is switched between the cooling mode and the heating mode depending on the room temperature detected by the temperature sensor 17, and the thermal medium supplied to the coil 11 is changed between the cold thermal medium and the hot thermal medium by opening and closing the first to fourth shutoff valves 31 to 34, which provides an advantageous effect that cooling or heating can be automatically and separately carried out based on the temperature in a room or a zone.

Further, the controller 18 and the control unit 40, which are explained as separate control apparatuses in the above-described embodiment, may be integrated into one control apparatus as long as the one control apparatus is able to perform the same functions as those of the controller 18 and the control unit 40.

Next, an air conditioning system 200 according to another embodiment of this invention will be described below. In this embodiment, two fan coil units 10a and dd ,, 10b are installed in one room or in one zone. A suffix of "a" is added to reference numerals for components in the fan coil unit 10a, while a suffix of "b" is added to reference numerals for components in the fan coil unit 10b. In addition, the same components as those of the embodiment described with reference to FIGS. 1 to 3 are designated by the same reference numerals as those of the above embodiment, and the descriptions related to those components will not be repeated.

As shown in FIG. 4, the fan coil units 10a and 10b include temperature sensors 17a and 17b, controllers 18a and 18b, and control valves 13a and 13b, respectively. Further, the controllers 18a and 18b are connected to each other through the data bus 41, and also connected to the control unit 40. The hot thermal medium feed pipe 22 is connected to both thermal medium supply pipes 14a and 14b in the fan coil units 10a and 10b, while the hot thermal medium recovery pipe 23 is connected to both thermal medium discharge pipes 15a and 15b in the fan coil units 10a and 10b. Similarly to this, the cold thermal medium feed pipe 26 is connected to both of the thermal medium supply pipes 14a and 14b in the fan coil units 10a and 10b, while the cold thermal medium recovery pipe 27 is connected to both of the thermal medium discharge pipes 15a and 15b in the fan coil units 10a and 10b.

Operation of the air conditioning system 200 structured as described above is described below. As described above, the room temperature set values TS1,

TS2 have been input from the not-illustrated separate device into the control unit 40. The room temperature set values TS1, TS2 have also been input through the ee _———— data bus 41 into each of the controllers 18a, 18b of the fan coil units 10a, 10b. Meanwhile, the room temperatures TRa, TRb detected by the temperature sensors 17a, 17b are respectively input into their controllers 18a, 18b, and information values of the room temperatures TRa, TRb are both input through the data bus 41 into the control unit 40.

As shown in FIG. 4, because the air conditioning system 200 in this embodiment has a common section of the hot thermal medium feed pipe 22, the hot thermal medium recovery pipe 23, the cold thermal medium feed pipe 26, the cold thermal medium recovery pipe 27,and the first to fourth shutoff valves 31 to 34 shared by the two fan coil units 10a and 10b, the two fan coil units 10a and 10b cannot receive different thermal media respectively at the same time. In other words, it is not possible for the cold thermal medium to be made to flow into one fan coil unitl0a, while the hot thermal medium is simultaneously made to flow into the other fan coil unit 10b. For this reason, when there is a difference between the room temperatures TRa and

TRb detected by the temperature sensors 17a and 17b, the control unit 40 causes the controllers 18a, 18b and the shutoff valves 31 to 34 to operate as described

Dbelow.

First, when both of the room temperatures TRa and

TRb match or exceed the room temperature set value TS1 (the set value for cooling) (TRa 2 TS1 and TRb 2 TS1), the control unit 40 causes both of the controllers 18a, 18b to operate in the cooling mode. In addition, as in the case of the previous embodiment described above, the control unit 40 closes the first and second shutoff valves 31, 32 and opens the third and fourth shutoff valves 33, 34. This directs the cold thermal medium (cold water) from the freezer 25 to flow in the order of "freezer 25 -> cold thermal medium feed pipe 26 -> third shutoff valve 33 -> thermal medium supply pipes l4a, 14b -> control valves 13a, 13b -> coils lla, 1llb - > thermal medium discharge pipes 15a, 15b -> fourth shutoff valve 34 -> cold thermal medium recovery pipe 27 -> freezer 25", and accordingly coolsthe air that is made to flow outside the coils 1la, 11b by the fans 12a, 12b. In this way, cooling of the room is performed.

On the other hand, when both of the room temperatures TRa and TRb match or fall below the room temperature set value TS2 (the set value for heating) (TRa £ TS2 and TRb £ TS2), the control unit 40 causes both of the controllers 18a, 18b to operate in the heating mode. In addition, as in the case of the previous embodiment, the control unit 40 opens the first and second shutoff valves 31, 32 and closes the third and fourth shutoff valves 33, 34. This directs the hot thermal medium (hot water) from the boiler 21 to flow in the order of "boiler 21 -> hot thermal medium feed pipe 22 -> first shutoff valve 31 -> hot thermal medium feed pipes 14a, 14b -> control valves 13a, 13b -> coils lla, 1llb -> thermal medium discharge pipes 15a, 15b -> second shutoff valve 32 -> hot thermal medium recovery pipe 23 -> boiler 21", and accordingly heats the air that is made to flow outside the coils lla, 11b by the fans 12a, 12b, which, in turn, performs heating of the room.

LT a a

AIR CONDITIONING SYSTEM CTT ren

PRIORITY INFORMATION

This application claims priority to Japanese

Patent Application No. 2015-098350filed on May 13, 2015, which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

The present invention relates to an air conditioning system, and in particular, the structure of an air conditioning system used in a building that houses various offices, stores, and the like.

BACKGROUND ART

In a building that houses various offices, stores, and the like, it is desirable that cooling and heating can be switched separately for each of rooms or zones.

To perform air conditioning in this way, air i 20 conditioning systems have been suggested in which a thermal medium delivered to a fan coil unit installed in each room or each zone can be replaced between cold water and hot water (refer to, for example, JP HO7- 83446 A).

A fan coil unit in an air conditioning system described in JP H07-83446 A is a so-called two pipe fan coil unit equipped with two pipes of a thermal medium inlet pipe and a thermal medium outlet pipe for a thermal medium (hot water or cold water), in which the thermal medium inlet pipe of the fan coil unit is connected to a cold water delivery pipe and a hot water delivery pipe, while the thermal medium outlet pipe of

In the presence of the difference between the room temperatures TRa and TRb, there are two different schemes that may be performed by the control unit 40 to operate the controllers 18a, 18b and the control valves 13a, 13b. In a first scheme, the control unit 40 calculates an average of the room temperatures TRa and

TRb to obtain an average room temperature TRm, and uses the average room temperature TRm as a representative temperature of a room or a zone, in which the two fan coil units 10a and 10b are installed, for setting operation modes of the controllers 18a, 18b and switching positions of the shutoff valves 31 to 34.

For example, in a case where the room temperature TRa is higher than the room temperature set value TS1 (the set value for cooling), the room temperature TRb is lower than the room temperature set value TS1 (the set value for cooling), and the average room temperature

TRm is higher than the room temperature set value TS1 (the set value for cooling), the control unit 40 causes both of the controllers 18a, 18b in the fan coil units 10a, 10b to operate in the cooling mode in addition to closing the first and second shutoff valves 31, 32, and opening the third and fourth shutoff valves 33, 34 to direct the cold thermal medium (cold water) from the freezer 25 into both of the coils 1la, 1lb. In this case, because the room temperature TRa detected by the temperature sensor 17a is higher than the room temperature set value TS1 (the set value for cooling), the opening of the control valve 13a in the fan coil unit 10a is changed based on the room temperature TRa as shown in FIG. 2, to cool down room air with the fan coil unit 10a. On the other hand, in the fan coil unit

TTT ————///— lo 10b which is also operated in the cooling mode, the opening of the control valve 13b is maintained at 0% as shown in FIG. 2 while the room temperature TRb detected by the temperature sensor 17b is lower than the room temperature set value TS1 (the set value for cooling), and is further maintained at 0% as shown in FIG. 2 even after the room temperature TRb detected by the temperature sensor 17b falls below the room temperature set value TS2 (the set value for heating).

Accordingly, even though room air is made to flow into the fan coil unit 10b by the fan 12b, cooling of the room air is not performed, which can prevent excessive cooling of the room air present in the vicinity of the fan coil unit 10b. It should be noted that when one of the fan coil units 10a and 10b is not active, the average is not calculated, and an output from the temperature sensor 17a or l1l7bfor the active one of the fan coil units 10a and 10b is used to set the operation mode of the controller 18a or 18b in the active one of the fan coil units 10a and 10b, and switch the shutoff valves 31 to 34.

In a second scheme, a temperature detected by the temperature sensor 17a or 1l7bforeither one of the two fan coil units 10a and 10b is preferentially used. The preferentially used temperature sensor is a specific one of the temperature sensors 17a and 17b. For example, when the room temperature TRa detected by the temperature sensor 17a for the fan coil unit 10a is preferentially used, the temperature sensor 17a is selected as the preferential sensor, and setting of both of the operation modes for the controllers 18a, 18b and switching of the shutoff valves 31 to 34 are

EE — performed based on the room temperature TRa regardless of the room temperature TRb detected by the temperature sensor 17b for the fan coil unit 10b. In this case, when the fan coil unit 10a is inactive, operation is carried out as in the case of the above-described first method. That is, an output from the temperature sensor 17bof the active fan coil unit 10b is used for setting the operation mode of the controller 18b and switching the positions of the shutoff valves 31 to 34.

Up to this point, cooling operation has been described. Heating operation is performed in the same way, and actions performed when the room temperatures

TRa, TRb are changed are identical to those described above with reference to FIGS. 1 to 3.

In the air conditioning system 200 according to the embodiment of FIG. 4, the two fan coil units 10a and 10b share, as the common structure, the hot thermal medium feed pipe 22, the hot thermal medium recovery pipe 23, the cold thermal medium feed pipe 26, the cold thermal medium recovery pipe 27, and the first to fourth shutoff valves 31 to 34. When there is a difference between the room temperatures TRa and TRb detected by the temperature sensors 17a and 17b, both operations of the controllers 18a, 18b are changed together to the cooling mode or the heating mode in addition to opening and closing the control valves 31 to 34 to switch the thermal medium supplied to the coils lla, 1llb between the cold thermal medium and the hot thermal medium based on either the average value

TRm of the room temperatures TRa, TRb or the room temperature TRa or Trb detected by the specific one of the temperature sensors 17a or 17b. As a result, the operation mode of the controllers 18a, 18b can be matched with the type of the thermal medium to be supplied, and cooling and heating can be smoothly changed. In this way, even in the presence of a difference between the room temperatures TRa, TRb detected by the temperature sensors 17a, 17b, the room temperature can be preferably controlled to prevent excessive cooling or heating. Thus, similarly to the air conditioning system 100 explained above with reference to FIGS. 1 to 3, the air conditioning system 200 can separately perform cooling and heating for rooms or zones based on the temperature of each of the rooms Or zones.

In the above, although the structure and operation of the air conditioning system 200 equipped with the two fan coil units 10a and 10b have been described with reference to FIG. 4, the present invention may be applied to an air conditioning system equipped with three or more fan coil units. In this case, similarly to the above-described operation, all of the controllers are operated in the cooling mode when all of the room temperatures detected by the room temperature sensors in the fan coil units are higher than the room temperature set value TS1l (the set value for cooling), while all of the controllers are operated in the heating mode when all of the room temperatures are lower than the room temperature set value TS2 (the set value for heating). Further, when there is a variation among the room temperatures detected by the room temperature sensors, an average of the room temperatures is calculated to obtain the average room temperature TRm as the representative temperature ofthe

CT room or zone in which all of the fan coil units are installed, and based on the average room temperature

TRm, setting of the operation modes of the controllers and switching of positions of the shutoff valves 31 to 34 may be performed. Alternatively, a room temperature detected by one of the temperature sensors may be preferentially used, and the setting of the operation modes of the controllers and switching of positions of the shutoff valves 31 to 34 may be performed based on the room temperature detected by the one of the temperature sensors.

the fan coil unit is connected to a cold water recovery pipe and a hot water recovery pipe. Further, all of the delivery and recovery pipes are equipped with shutoff valves, respectively. In this system, cold water is introduced into the fan coil unit by opening the shutoff valves arranged in the cold water delivery pipe and the cold water recovery pipe while closing the shutoff valves arranged in the hot water delivery pipe and the hot water recovery pipe to perform cooling, while, on the other hand, hot water is introduced into the fan coil unit by opening the shutoff valves arranged in the hot water delivery pipe and the hot water recovery pipe while closing the shutoff valves arranged in the cold water delivery pipe and the cold water recovery pipe, to carry out heating. In this way, operation is switched between cooling and heating.

However, the system described in JP H07-83446 A needs manual inputs from an input terminal to open and close the shutoff valves, and accordingly has a problem in that it is difficult to switch between cooling and heating separately depending on temperature of each room or zone.

Meanwhile, so-called four pipe fan coil units have often been used, in which two coils consisting of a cold water coil to which cold water is directed to flow therein and a hot water coil to which hot water is directed to flow therein are arranged with four pipes consisting of a hot water inlet pipe, a hot water outlet pipe, a cold water inlet pipe, and a cold water outlet pipe. In the four pipe fan coil unit, because it is not necessary to change thermal media to be introduced into the coils, cooling and heating can be performed automatically and separately depending on temperature of each room or zone. An air conditioning system using the four pipe fan coil unit, however, suffers from problems of an increased size of the fan coil unit and increased installation costs due to the presence of the four pipes that should be arranged between the fan coil unit and thermal medium supply apparatuses, such as a freezer and a boiler.

SUMMARY

One of the advantageous effects of the present invention is to perform cooling and heating separately depending on temperature of each of rooms or zones, with a simple method.

An air conditioning system according to an aspect of the present invention comprises a fan coil unit that includes a coil through which a hot thermal medium having a temperature higher than that of room air or a cold thermal medium having a temperature lower than that of room air is made to flow to exchange heat with room air flowing outside the coil, a fan for directing room air to flow outside the coil, a control valve for controlling a flow rate of the hot thermal medium or the cold thermal medium flowing through the coil, a thermal medium supply pipe for supplying the hot thermal medium or the cold thermal medium to the coil, a thermal medium discharge pipe for discharging the hot thermal medium or the cold thermal medium from the coil, a temperature sensor for detecting a room air temperature, and a controller for actuating the control valve depending on the room air temperature detected by the temperature sensor. The air conditioning system

ERE EEE —————————— ——————————————————————————eeeseeseeseeeeeeeeeeee sees ee" == =e ap este further comprises a thermal medium supply apparatus for supplying the hot thermal medium or the cold thermal medium, a hot thermal medium feed pipe for feeding the hot thermal medium from the thermal medium supply apparatus to the thermal medium supply pipe, a hot thermal medium recovery pipe for recovering the hot thermal medium from the thermal medium discharge pipe to the thermal medium supply apparatus, a cold thermal medium feed pipe for feeding the cold thermal medium from the thermal medium supply apparatus to the thermal medium supply pipe, a cold thermal medium recovery pipe for recovering the cold thermal medium from the thermal medium discharge pipe to the thermal medium supply apparatus, a first shutoff valve arranged in the hot thermal medium feed pipe, a second shutoff valve arranged in the hot thermal medium recovery pipe, a third shutoff valve arranged in the cold medium feed pipe, a fourth shutoff valve arranged in the cold thermal medium recovery pipe, and a control unit that receives a room temperature information value from the controller and performs operation to open and close the first to fourth shutoff valves.

In this air conditioning system, when the room temperature information value is lower than a room air temperature set value, the first and second shutoff valves are opened, while the third and fourth shutoff valves are closed.

On the other hand, when the room temperature information value is higher than the room air temperature set value, the third and fourth shutoff valves are opened, while the first and second shutoff valves are closed.

Preferably, in the air conditioning system according to the present invention, the control unit may send the room air temperature set value to the controller, and the controller may be operable in a heating mode and in a cooling mode. In the heating mode, the controller may actuate the control valve depending on the room temperature when the room temperature detected by the temperature sensor is lower than the room air temperature set value received from the control unit, and may close the control valve when the room temperature detected by the temperature sensor is higher than the room air temperature set value received from the control unit. In the cooling mode, the controller may actuate the control valve depending on the room temperature when the room temperature detected by the temperature sensor is higher than the room air temperature set value received from the control unit, and may close the control valve when the room temperature detected by the temperature sensor is lower than the room air temperature set value received from the control unit. Also preferably, in the air conditioning system, the control unit may open the first and second shutoff valves and close the third and fourth shutoff valves in addition to causing the controller to operate in the heating mode, or may open the third and fourth shutoff valves and close the first and second shutoff valves in addition to causing the controller to operate in the cooling mode.

Preferably, the air conditioning system according to the present invention may include a plurality of fan coil units, and the control unit may receive room temperature information values from the controllers in

EE ———— ee — the plurality of fan coil units. In this system, when all of the received room temperature information values are lower than the room air temperature set value, the first and second shutoff valves may be opened, while the third and fourth shutoff valves may be closed, and when all of the received room temperature information vales are higher than the room air temperature set value, the third and fourth shutoff valves may be opened, while the first and second shutoff valves may be closed.

Still preferably, the air conditioning system of the present invention may include the plurality of fan coil units, and the control unit may receive the room temperature information values from the controllers in the plurality of fan coil units. In this system, when an average value of the room temperature information values is lower than the room air temperature set value, the first and second shutoff valves may be opened, while the third and fourth shutoff valves may be closed, and when the average value of the room temperature information values is higher than the room air temperature set value, the third and fourth shutoff valves may be opened, while the first and second shutoff valves may be closed.

Also preferably, the air conditioning system of the present invention may include the plurality of fan coil units, and the control unit may receive the room temperature information values from the controllers in the plurality of fan coil units. In this system, when a specific one of the room temperature information values is lower than the room air temperature set value, the first and second shutoff valves may be

Ce —————————————— opened, while the third and fourth shutoff valves may be closed, and when the specific one of the room temperature information values is higher than the room air temperature set value, the third and fourth shutoff valves may be opened, while the first and second shutoff valves may be closed.

Still preferably, in the air conditioning system of the present invention, the control unit may send the room air temperature set value to the controllers, and the controllers may be operable in the heating mode and in the cooling mode. In the heating mode, each of the controllers may actuate its corresponding control valve based on the room temperature when the room temperature detected by the corresponding temperature sensor is lower than the room air temperature set value received from the control unit, and may close the corresponding control valve when the room temperature detected by the corresponding temperature sensor is higher than the room air temperature set value received from the control unit. In the cooling mode, each of the controllers may actuate its corresponding control valve based on the room temperature when the room temperature detected by the corresponding temperature sensor is higher than the room air temperature set value received from the control unit, and may close the corresponding control valve when the room temperature detected by the corresponding temperature sensor is lower than the room air temperature set value received from the control unit. Preferably, the control unit may cause all of the controllers to operate in the heating mode in addition to opening the first and second shutoff valves and closing the third and fourth shutoff valves, or may cause all of the controllers to operate in the cooling mode in addition to opening the third and fourth shutoff valves and closing the first and second shutoff valves.

ADVANTAGES OF THE INVENTION

The present invention has an advantageous effect that cooling and heating can be performed separately depending on temperature of each room or zone with a simple method.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be further described with reference to the accompanying drawings, wherein like reference numerals refer to like parts in the several views, and wherein:

FIG. 1 is a system diagram showing components of an air conditioning system according to an embodiment of the present invention;

FIG. 2 is a graph showing a cooling-mode action of a control valve in the air conditioning system according to the embodiment of the present invention;

FIG. 3 is a graph showing a heating-mode action of the control valve in the air conditioning system according to the embodiment of the present invention; and

FIG. 4 is a system diagram showing components of the air conditioning system according to another embodiment of the present invention.

Claims

vis Cree What is Claimed is: Ceenile Tas

1. An air conditioning system, comprising: a plurality of fan coil units, each including; a coil in which a hot thermal medium having a temperature higher than that of room air or a cold thermal medium having a temperature lower than that of room air is introduced to exchange heat with room air that is made to flow outside the coil, a fan for directing room air to flow outside the coil, a control valve for controlling a flow rate of the hot thermal medium or the cold thermal medium that flows through the coil, a thermal medium supply pipe for supplying the hot thermal medium or the cold thermal medium to the coil, a thermal medium discharge pipe for discharging the hot thermal medium or the cold thermal medium from the coil, a temperature sensor for detecting a room air temperature, and a controller for actuating the control valve based on the room air temperature detected by the temperature sensor; the air conditioning system further comprising: a thermal medium supply apparatus for supplying the hot thermal medium or the cold thermal medium; a hot thermal medium feed pipe for feeding the hot thermal medium from the thermal medium supply apparatus to the respective thermal medium supply pipes:

a hot thermal medium recovery pipe for recovering the hot thermal medium from the respective hot thermal medium discharge pipes to the thermal medium supply apparatus;

a cold thermal medium feed pipe for feeding the cold thermal medium from the thermal medium supply apparatus to the respective thermal medium supply pipes;

a cold thermal medium recovery pipe for recovering the cold thermal medium from the respective thermal medium discharge pipes to the thermal medium supply apparatus;

a first shutoff valve arranged in the hot thermal medium feed pipe:

a second shutoff valve arranged in the hot thermal medium recovery pipe;

a third shutoff valve arranged in the cold thermal medium feed pipe;

a fourth shutoff valve arranged in the cold thermal medium recovery pipe; and a control unit that receives room temperature information values respectively from the controllers in the plurality of fan coil units and performs operation to open and close the first to fourth shutoff valves,

wherein when all of the room temperature information values are lower than a room air temperature set value, the control unit opens the first and second shutoff valves and closes the third and fourth shutoff valves,

and when all of the room temperature information values are higher than the room air temperature set value, the control unit opens the third and fourth shutoff valves and closes the first and second shutoff valves.

2. The air conditioning system according to Claim 1, wherein: when an average value of the room temperature information values is lower than the room air temperature set value, the control unit opens the first and second shutoff valves and closes the third and fourth shutoff valves; and when the average value of the room temperature information values is higher than the room air temperature set value, the control unit opens the third and fourth shutoff valves and closes_the first and second shutoff valves.

3. The air conditioning system according to Claim 1, wherein: when a specific one of the room temperature information values is lower than the room air temperature set value, the control unit opens the first and second shutoff valves and closes the third and fourth shutoff valves, and when the specific one of the room temperature information values is higher than the room air temperature set value, the control unit opens the third and fourth shutoff valves and closes the first and second shutoff valves.

4. The air conditioning system according to any one of Claims 1 to 3, wherein:

Ee — the control unit sends the room temperature set value to the controllers; each of the controllers is operable in a heating mode and in a cooling mode;

in the heating mode, each of the controllers actuates its corresponding control valve based on the room temperature when the room temperature detected by the corresponding temperature sensor is lower than the room air temperature set value received from the control unit, and closes the corresponding control

: valve when the room temperature detected by the corresponding temperature sensor is higher than the room air temperature set value;

in the cooling mode, each of the controllers actuates its corresponding control valve based on the room temperature when the room temperature detected by the corresponding temperature sensor is higher than the room air temperature set value received from the control unit, and closes the corresponding control valve when the room temperature detected by the corresponding temperature sensor is lower than the room air temperature set value received from the control unit; and the control unit opens the first and second shutoff valves and closes the third and fourth shutoff valves in addition to causing all of the controllers to operate in the heating mode, or opens the third and fourth shutoff valves and closes the first and second shutoff valves in addition to causing all of the controllers to operate in the cooling mode.