Patent Grant
9897359
This application is a U.S. national stage application of International Patent Application No. PCT/JP2012/000258 filed on Jan. 18, 2012.
The present invention relates to an air-conditioning apparatus which is used as, for example, a multi-air-conditioning apparatus for a building.
There is an air-conditioning apparatus that allows a heat source side refrigerant circulated through a refrigeration cycle (refrigerant circuit) to exchange heat with an indoor side refrigerant (heat medium) circulated through a heat medium circuit. The refrigeration cycle includes an outdoor unit and a relay unit connected by pipes. The heat medium circuit includes the relay unit and an indoor unit connected by pipes. Air-conditioning apparatuses having such a configuration used as building multi-air-conditioning apparatuses include an air-conditioning apparatus configured such that conveyance power for the heat medium is reduced to achieve energy saving (refer to Patent Literature 1, for example). The reason why the two circuits are arranged as described above is that a refrigerant, such as water, having no adverse effects on health of users in a building can be used as the heat medium circulated in an indoor space.
Patent Literature 1: International Publication No. WO 2010/049998 (p. 3, FIG. 1, for example)
For example, typical air-conditioning apparatuses for conditioning air without using any heat medium have been designed so that the leakage of a refrigerant can be immediately detected and dealt with in consideration of influences on users. On the other hand, little attention has been focused on detection of the leakage of a heat medium from a heat medium circuit in an air-conditioning apparatus like that disclosed in Patent Literature 1 described above because the heat medium circulated in an indoor space exerts little adverse effect on users.
However, the leakage of the heat medium, for example, will affect air conditioning control, components, and the like. For instance, if the heat medium leaks from the heat medium circuit through which the heat medium is circulated by a pump, air may enter the heat medium circuit, thus causing air entrainment in the pump. This may result in a significantly reduced circulation of the heat medium. Unfortunately, the pump may be overheated and broken. Alternatively, if current supplied to the pump or the temperature of the pump is affected by the leakage of the heat medium, the pump may have been damaged. At worst, the pump may be broken.
Although the leakage or the like of the heat medium can be detected on the basis of a change in temperature of the heat medium, it is difficult to accurately detect the leakage because the degree of change in temperature of the heat medium varies with the amount of water.
The present invention has been made to solve the above-described disadvantage and provides an air-conditioning apparatus capable of more efficiently detecting abnormality in flow rate of a heat medium flowing through a heat medium circuit.
The present invention provides an air-conditioning apparatus including a refrigeration cycle configured by connecting, by a pipe, a compressor configured to compress a heat source side refrigerant, a refrigerant flow switching device configured to switch between paths for circulation of the heat source side refrigerant, a heat source side heat exchanger configured to allow the heat source side refrigerant to exchange heat, an expansion device configured to regulate the pressure of the heat source side refrigerant, and at least one intermediate heat exchanger configured to exchange heat between the heat source side refrigerant and a heat medium different from the heat source side refrigerant and in which the compressor, the refrigerant flow switching device, a heat medium circuit configured by connecting, by a pipe, at least one pump configured to circulate the heat medium for heat exchange by the intermediate heat exchanger, a use side heat exchanger configured to exchange heat between the heat medium and air in an air-conditioning target space, and a flow switching valve configured to switch between passing the heated heat medium through the use side heat exchanger and passing the cooled heat medium through the use side heat exchanger, and a controller configured to calculate an actual temperature efficiency ratio based on a temperature at a heat medium inlet of the heat exchanger in the heat medium circuit and determine whether a flow rate of the heat medium in the heat medium circuit is abnormal based on the actual temperature efficiency ratio and a set reference temperature efficiency ratio.
In the air-conditioning apparatus according to the present invention, since the controller determines whether abnormality in flow rate has occurred based on the temperature efficiency ratio related to heat exchange by the heat exchanger in the heat medium circuit. Thus, the abnormality in flow rate can be determined accurately and efficiently.
As illustrated in
The heat source unit 1 is typically disposed in an outdoor space 6 that is a space outside a structure 9, such as a building, and is configured to supply cooling energy or heating energy to the indoor units 2 via the relay unit 3. Each indoor unit 2 is disposed in a living space 7, such as a living room or a server room inside the structure 9, to which cooling air or heating air can be conveyed, and is configured to supply the cooling air or the heating air to the living space 7, serving as an air-conditioning target area. The relay unit 3 includes a housing separated from housings of the heat source unit 1 and the indoor units 2 such that the relay unit 3 can be disposed in a different position (hereinafter, referred to as a “non-living space 50”) from those of the outdoor space 6 and the living spaces 7. The relay unit 3 connects the heat source unit 1 and the indoor units 2 to transfer cooling energy or heating energy, supplied from the heat source unit 1, to the indoor units 2.
The outdoor space 6 is supposed to be a place outside the structure 9, for example, a roof as illustrated in
The heat source unit 1 and the relay unit 3 are connected using two refrigerant pipes 4. The relay unit 3 and each indoor unit 2 are connected using two pipes 5. Connecting the heat source unit 1 to the relay unit 3 using the two refrigerant pipes 4 and connecting each indoor unit 2 to the relay unit 3 using the two pipes 5 in this manner facilitate construction of the air-conditioning apparatus.
As illustrated in
Although
Although
Furthermore, the relay unit 3 can be disposed near the heat source unit 1. If the distance between the relay unit 3 and each indoor unit 2 is too large, the conveyance power for the heat medium would be considerably large, leading to a reduction in the effect of energy saving.
(Heat Source Unit 1)
The heat source unit 1 includes a compressor 10, a four-way valve 11, a heat source side heat exchanger (outdoor heat exchanger) 12, and an accumulator 17 which are connected in series by the refrigerant pipes 4. The heat source unit 1 further includes a first connecting pipe 4a, a second connecting pipe 4b, a check valve 13a, a check valve 13b, a check valve 13c, and a check valve 13d. The arrangement of the first connecting pipe 4a, the second connecting pipe 4b, and the check valves 13a, 13b, 13c, and 13d enables the heat source side refrigerant, allowed to flow into the relay unit 3, to flow in a given direction irrespective of an operation requested by any indoor unit 2.
The compressor 10 is configured to suck the heat source side refrigerant and compress the heat source side refrigerant into a high-temperature high-pressure state and may be, for example, a capacity-controllable inverter compressor. The four-way valve 11 is configured to switch between the direction of flow of the heat source side refrigerant during the heating operation and the direction of flow of the heat source side refrigerant during the cooling operation. The heat source side heat exchanger 12 is configured to function as an evaporator during the heating operation and function as a condenser during the cooling operation so as to exchange heat between the heat source side refrigerant and air supplied from an air-sending device (not illustrated), such as a fan, such that the heat source side refrigerant evaporates and gasifies or condenses and liquefies. The accumulator 17 is disposed on a suction side of the compressor 10 and is configured to store an excess of the refrigerant.
The check valve 13d is disposed in the refrigerant pipe 4 between the relay unit 3 and the four-way valve 11 and is configured to permit the heat source side refrigerant to flow only in a predetermined direction (the direction from the relay unit 3 to the heat source unit 1). The check valve 13a is provided to the refrigerant pipe 4 between the heat source side heat exchanger 12 and the relay unit 3 and is configured to permit the heat source side refrigerant to flow only in a predetermined direction (the direction from the heat source unit 1 to the relay unit 3). The check valve 13b is disposed in the first connecting pipe 4a and is configured to permit the heat source side refrigerant to flow only in a direction from a point downstream of the check valve 13d to a point downstream of the check valve 13a. The check valve 13c is disposed in the second connecting pipe 4b and is configured to permit the heat source side refrigerant to flow only in a direction from a point upstream of the check valve 13d to a point upstream of the check valve 13a.
The first connecting pipe 4a connects the refrigerant pipe 4 downstream of the check valve 13d and the refrigerant pipe 4 downstream of the check valve 13a in the heat source unit 1. The second connecting pipe 4b connects the refrigerant pipe 4 upstream of the check valve 13d and the refrigerant pipe 4 upstream of the check valve 13a in the heat source unit 1. Although
(Indoor Units 2)
The indoor units 2 each include a use side heat exchanger 26. The use side heat exchanger 26 is connected through the pipes 5 to a stop valve 24 and a flow control valve 25 which are arranged in the second relay unit 3b. The use side heat exchanger 26 is configured to exchange heat between the heat medium and air supplied by driving of an indoor fan 28 in order to produce heating air or cooling air to be supplied to the air-conditioning target area.
(Relay Unit 3)
The relay unit 3 is composed of the first relay unit 3a and the second relay unit 3b which include separate housings. As described above, this configuration enables a plurality of second relay units 3b to be connected to the single first relay unit 3a. The first relay unit 3a includes a gas-liquid separator 14 and an expansion valve 16e. The second relay unit 3b includes the two intermediate heat exchangers 15, four expansion valves 16, two pumps 21, four flow switching valves 22, four flow switching valves 23, the four stop valves 24, and the four flow control valves 25.
The gas-liquid separator 14 is connected to one refrigerant pipe 4 that connects to the heat source unit 1 and two refrigerant pipes 4 that connect to the first intermediate heat exchanger 15a and the second intermediate heat exchanger 15b in the second relay unit 3b, and is configured to separate the heat source side refrigerant supplied from the heat source unit 1 into a vapor refrigerant and a liquid refrigerant. The expansion valve 16e is disposed between the gas-liquid separator 14 and the refrigerant pipe 4 that connects the expansion valve 16a and the expansion valve 16b and is configured to function as a pressure reducing valve or an expansion device so as to reduce the pressure of the heat source side refrigerant such that the refrigerant is expanded. The expansion valve 16e may be a component having a variably controllable opening degree, for example, an electronic expansion valve.
The two intermediate heat exchangers 15 (the first intermediate heat exchanger 15a and the second intermediate heat exchanger 15b) are configured to function as a heating device (condenser) or a cooling device (cooler), exchange heat between the heat source side refrigerant and the heat medium, and supply cooling energy or heating energy produced by the heat source unit 1 to the indoor units 2. The first intermediate heat exchanger 15a is disposed between the gas-liquid separator 14 and the expansion valve 16d in the flow direction of the heat source side refrigerant and is used to heat the heat medium. The second intermediate heat exchanger 15b is disposed between the expansion valves 16a and 16c in the flow direction of the heat source side refrigerant and is used to cool the heat medium.
The four expansion valves 16 (expansion valves 16a to 16d) are configured to function as a pressure reducing valve or an expansion device and reduce the pressure of the heat source side refrigerant such that the refrigerant is expanded. The expansion valve 16a is disposed between the expansion valve 16e and the second intermediate heat exchanger 15b. The expansion valve 16b is disposed in parallel to the expansion valve 16a. The expansion valve 16c is disposed between the second intermediate heat exchanger 15b and the first relay unit 3a. The expansion valve 16d is disposed between the first intermediate heat exchanger 15a and the expansion valves 16a and 16b. Each of the four expansion valves 16 may be a component having a variably controllable opening degree, for example, an electronic expansion valve.
The two pumps 21 (a first pump 21a and a second pump 21b) are configured to circulate the heat medium conveyed through the pipe 5. The first pump 21a is provided to the pipe 5 between the first intermediate heat exchanger 15a and the flow switching valves 22. The second pump 21b is provided to the pipe 5 between the second intermediate heat exchanger 15b and the flow switching valves 22. Each of the first pump 21a and the second pump 21b may be of any type, for example, a capacity-controllable pump.
Each of the four flow switching valves 22 (flow switching valves 22a to 22d) is a three-way valve and is configured to switch between passages for the heat medium. The flow switching valves 22 which are equal in number to the (four in this case) indoor units 2 installed are arranged. Each flow switching valve 22 is disposed on an inlet side of a heat medium passage of the corresponding use side heat exchanger 26 such that one of three ways is connected to the first intermediate heat exchanger 15a, another one of the three ways is connected to the second intermediate heat exchanger 15b, and the other one of the three ways is connected to the stop valve 24. Note that the flow switching valve 22a, the flow switching valve 22b, the flow switching valve 22c, and the flow switching valve 22d are illustrated in that order from the bottom of the drawing sheet so as to correspond to the respective indoor units 2.
Each of the four flow switching valves 23 (flow switching valves 23a to 23d) is a three-way valve and is configured to switch between passages for the heat medium. The flow switching valves 23 which are equal in number to the (four in this case) indoor units 2 installed are arranged. Each flow switching valve 23 is disposed on an outlet side of the heat medium passage of the corresponding use side heat exchanger 26 such that one of three ways is connected to the first intermediate heat exchanger 15a, another one of the three ways is connected to the second intermediate heat exchanger 15b, and the other one of the three ways is connected to the flow control valve 25. Note that the flow switching valve 23a, the flow switching valve 23b, the flow switching valve 23c, and the flow switching valve 23d are illustrated in that order from the bottom of the drawing sheet so as to correspond to the respective indoor units 2.
Each of the four stop valves 24 (stop valves 24a to 24d) is a two-way valve and is configured to open or close the pipe 5. The stop valves 24 which are equal in number to the (four in this case) indoor units 2 installed are arranged. Each stop valve 24 is disposed on the inlet side of the heat medium passage of the corresponding use side heat exchanger 26 such that one of two ways is connected to the use side heat exchanger 26 and the other one of the two ways is connected to the flow switching valve 22. Note that the stop valve 24a, the stop valve 24b, the stop valve 24c, and the stop valve 24d are illustrated in that order from the bottom of the drawing sheet so as to correspond to the respective indoor units 2.
Each of the four flow control valves 25 (flow control valves 25a to 25d) is a three-way valve and is configured to switch between passages for the heat medium. The flow control valves 25 which are equal in number to the (four in this case) indoor units 2 installed are arranged. Each flow control valve 25 is disposed on the outlet side of the heat medium passage of the corresponding use side heat exchanger 26 such that one of three ways is connected to the use side heat exchanger 26, another one of the three ways is connected to a bypass 27, and the other one of the three ways is connected to the flow switching valve 23. Note that the flow control valve 25a, the flow control valve 25b, the flow control valve 25c, and the flow control valve 25d are illustrated in that order from the bottom of the drawing sheet so as to correspond to the respective indoor units 2.
Each bypass 27 is disposed so as to connect the flow control valve 25 and the pipe 5 between the stop valve 24 and the use side heat exchanger 26. The bypasses 27 which are equal in number to the (four in this case) indoor units 2 installed, specifically, a bypass 27a, a bypass 27b, a bypass 27c, and a bypass 27d are arranged. Note that the bypass 27a, the bypass 27b, the bypass 27c, and the bypass 27d are illustrated in that order from the bottom of the drawing sheet so as to correspond to the respective indoor units 2.
The second relay unit 3b further includes two first temperature sensors 31, two second temperature sensors 32, four third temperature sensors 33, four fourth temperature sensors 34, a fifth temperature sensor 35, a pressure sensor 36, a sixth temperature sensor 37, and a seventh temperature sensor 38. Furthermore, each indoor unit includes an eighth temperature sensor 39. Signals indicating physical quantities detected by such detecting devices are transmitted to a controller 60 that controls an operation of the air-conditioning apparatus 100 which will be described later. The signals are used to control, for example, a driving frequency of each pump 21 and switching between passages for the heat medium flowing through the pipes 5.
The first temperature sensors 31 (a first temperature sensor 31a and a first temperature sensor 31b), serving as outgoing heat medium temperature detecting devices, each detect the temperature of the heat medium on an outlet side of a heat medium passage of the corresponding intermediate heat exchanger 15. The first temperature sensor 31a is provided to the pipe 5 on an inlet side of the first pump 21a. The first temperature sensor 31b is provided to the pipe 5 on an inlet side of the second pump 21b.
The second temperature sensors 32 (a second temperature sensor 32a and a second temperature sensor 32b), serving as incoming heat medium temperature detecting devices, each detect the temperature of the heat medium on an inlet side of the heat medium passage of the corresponding intermediate heat exchanger 15. The second temperature sensor 32a is provided to the pipe 5 on the inlet side of the heat medium passage of the first intermediate heat exchanger 15a. The second temperature sensor 32b is provided to the pipe 5 on the inlet side of the heat medium passage of the second intermediate heat exchanger 15b.
Each of the third temperature sensors 33 (third temperature sensors 33a to 33d), serving as use-side incoming temperature detecting devices, is disposed on the inlet side of the heat medium passage of the use side heat exchanger 26 in the corresponding indoor unit 2 and detects the temperature of the heat medium flowing into the use side heat exchanger 26. In
Each of the fourth temperature sensors 34 (fourth temperature sensors 34a to 34d), serving as use-side outgoing temperature detecting devices, is disposed on the outlet side of the heat medium passage of the use side heat exchanger 26 in the corresponding indoor unit 2 and detects the temperature of the heat medium flowing out of the use side heat exchanger 26. In
The fifth temperature sensor 35 is disposed on an outlet side of a heat source side refrigerant passage of the first intermediate heat exchanger 15a and is configured to detect the temperature of the heat source side refrigerant flowing out of the first intermediate heat exchanger 15a. The pressure sensor 36 is disposed on the outlet side of the heat source side refrigerant passage of the first intermediate heat exchanger 15a and is configured to detect the pressure of the heat source side refrigerant flowing out of the first intermediate heat exchanger 15a.
The sixth temperature sensor 37 is disposed on an inlet side of a heat source side refrigerant passage of the second intermediate heat exchanger 15b and is configured to detect the temperature of the heat source side refrigerant flowing into the second intermediate heat exchanger 15b. The seventh temperature sensor 38 is disposed on an outlet side of the heat source side refrigerant passage of the second intermediate heat exchanger 15b and is configured to detect the temperature of the heat source side refrigerant flowing out of the second intermediate heat exchanger 15b.
The eighth temperature sensors 39 (eighth temperature sensors 39a to 39d), serving as air-conditioning target temperature detecting devices, each detect the temperature (indoor temperature) of air to be conditioned. In this case, each eighth temperature sensor 39 detects the temperature (sucked air temperature) of air allowed to flow into the use side heat exchanger 26 by driving of the indoor fan 28 in the corresponding indoor unit 2. In
The pipes 5 through which the heat medium is conveyed include the pipes 5 (hereinafter, referred to as “pipes 5a”) connected to the first intermediate heat exchanger 15a and the pipes 5 (hereinafter, referred to as “pipes 5b”) connected to the second intermediate heat exchanger 15b. Each of the pipes 5a and 5b branches into pipes (four pipes in this case) equal in number to the indoor units 2 connected to the relay unit 3. The pipes 5a and the pipes 5b are connected by the flow switching valves 22, the flow switching valves 23, and the flow control valves 25. Whether the heat medium conveyed through the pipe 5a is allowed to flow into the use side heat exchanger 26 or the heat medium conveyed through the pipe 5b is allowed to flow into the use side heat exchanger 26 is determined by controlling the corresponding flow switching valves 22 and 23.
The air-conditioning apparatus 100 further includes the controller 60 that controls operations of the components arranged in the heat source unit 1, the relay unit 3, and the indoor units 2 on the basis of information from a remote control for receiving instructions from various detecting means and a user. The controller 60 controls, for example, a driving frequency of the compressor 10 disposed in the heat source unit 1, a rotation speed (including ON/OFF) of the air-sending device disposed near the heat source side heat exchanger 12, and switching of the four-way valve 11 to perform any of operation modes, which will be described later. Furthermore, the controller 60 controls a rotation speed (including ON/OFF) of the indoor fan 28 disposed near the use side heat exchanger 26 included in each indoor unit 2.
In addition, the controller 60 controls driving of the pumps 21 arranged in the relay unit 3, opening degrees of the expansion valves 16a to 16e, switching of the flow switching valves 22 and the flow switching valves 23, opening and closing of the stop valves 24, and switching of the flow control valves 25. Specifically, the controller 60 has functions of flow control means for controlling the flow rate of the heat medium in the relay unit 3, functions of passage determining means for determining a heat medium passage, functions of ON/OFF control means for turning each component on or off, and functions of control target value changing means for appropriately changing a set target value on the basis of information from the various detecting means. In particular, according to Embodiment 1, the controller 60 performs a process of determining an abnormal flow rate of the heat medium in the heat medium circuits to protect the pumps 21. The controller 60 includes a microcomputer. The controller 60 further includes a timer 61, serving as a time measuring device, and is accordingly capable of measuring time. The controller 60 further includes a storage unit (not illustrated) for storing data or the like. The controller may be provided for each unit. In such a case, the controllers may preferably be enabled to communicate with each other.
The air-conditioning apparatus 100 according to Embodiment 1 further includes an annunciator 62. The annunciator 62 includes a display unit, an audio output unit, or the like to provide information with text displayed, audio output, or the like. The annunciator 62 may be included in, for example, the remote control. In Embodiment 1, when any of the pumps 21 is stopped due to, for example, abnormality in flow rate of the heat medium, the annunciator 62 provides information about such a state.
In the air-conditioning apparatus 100, the compressor 10, the four-way valve 11, the heat source side heat exchanger 12, the refrigerant passage of the first intermediate heat exchanger 15a, the refrigerant passage of the second intermediate heat exchanger 15b, and the accumulator 17 are connected by the refrigerant pipes 4 through which the refrigerant flows, thus providing the refrigeration cycle. In addition, the heat medium passage of the first intermediate heat exchanger 15a, the first pump 21a, and each use side heat exchanger 26 are sequentially connected in series by the pipes 5a through which the heat medium flows, thus providing a heat medium circuit for heating. Similarly, the heat medium passage of the second intermediate heat exchanger 15b, the second pump 21b, and each use side heat exchanger 26 are sequentially connected in series by the pipes 5b through which the heat medium flows, thus providing a heat medium circuit for cooling. Specifically, a plurality of use side heat exchangers 26 are connected in parallel with to one another each intermediate heat exchanger 15, thus providing a plurality of heat medium circuits, or heat medium systems. A heat medium circuit for heating is provided with a discharge valve 71a provided to the pipe 5a and the discharge valve 71a is configured to discharge the heat medium from this heat medium circuit. A heat medium circuit for cooling is provided with a discharge valve 71b provided to the pipe 5b and the discharge valve 71b is configured to discharge the heat medium from this heat medium circuit.
Specifically, in the air-conditioning apparatus 100, the heat source unit 1 is connected to the relay unit 3 through the first intermediate heat exchanger 15a and the second intermediate heat exchanger 15b arranged in the relay unit 3, and the relay unit 3 is connected to the indoor units 2 through the first intermediate heat exchanger 15a and the second intermediate heat exchanger 15b. The first intermediate heat exchanger 15a and the second intermediate heat exchanger 15b allow the heat source side refrigerant, serving as a primary refrigerant, circulated through the refrigeration cycle to exchange heat with the heat medium, serving as a secondary refrigerant, circulated through the heat medium circuits.
The kinds of refrigerant used in the refrigeration cycle and the heat medium circuits will now be described. In the refrigeration cycle, a non-azeotropic refrigerant mixture, such as R407C, a near-azeotropic refrigerant mixture, such as R410A or R404A, or a single refrigerant, such as R22 or R134a, can be used. Alternatively, a natural refrigerant, such as carbon dioxide or hydrocarbon, may be used. The use of the natural refrigerant as the heat source side refrigerant can reduce the Earth's greenhouse effect caused by refrigerant leakage. In particular, the use of carbon dioxide can improve heat exchange performance for heating or cooling the heat medium in the arrangement in which the heat source side refrigerant and the heat medium are allowed to flow in a counter-current manner in the first intermediate heat exchanger 15a and the second intermediate heat exchanger 15b as illustrated in
As described above, the heat medium circuits are connected to the use side heat exchangers 26 in the indoor units 2. Accordingly, the air-conditioning apparatus 100 is premised on the use of a highly safe heat medium in consideration of the leakage of the heat medium into a room or the like in which the indoor unit 2 is installed. As regards the heat medium, therefore, water, antifreeze, a liquid mixture of water and antifreeze, or the like can be used. A highly heat insulating fluorine inert liquid can be used as the heat medium in consideration of the installation of the indoor unit 2 in a place that dislikes moisture, for example, a computer room. If the heat source side refrigerant leaks from any refrigerant pipe 4, therefore, the leaked heat source side refrigerant can be prevented from entering an indoor space, thus providing high reliability.
<Operation Modes of Air-Conditioning Apparatus 100>
The operation modes performed by the air-conditioning apparatus 100 will now be described.
The air-conditioning apparatus 100 enables each indoor unit 2, on the basis of an instruction from the indoor unit 2, to perform the cooling operation or the heating operation. More specifically, the air-conditioning apparatus 100 enables all of the indoor units 2 to perform the same operation and also enables the indoor units 2 to perform different operations. In other words, the air-conditioning apparatus 100 according to Embodiment 1 is an air-conditioning apparatus capable of performing the cooling operation and the heating operation at the same time. Four operation modes performed by the air-conditioning apparatus 100, that is, a cooling only operation mode in which all of the operating indoor units 2 perform the cooling operation, a heating only operation mode in which all of the operating indoor units 2 perform the heating operation, a cooling main operation mode in which a cooling load is the larger, and a heating main operation mode in which a heating load is the larger will be described below in accordance with the flows of the refrigerants. For the sake of convenience, some of the temperature sensors and other components are not illustrated in
(Cooling Only Operation Mode)
In the cooling only operation mode illustrated in
First, the flow of the heat source side refrigerant in the refrigeration cycle will be described.
A low-temperature low-pressure refrigerant is compressed into a high-temperature high-pressure gas refrigerant by the compressor 10 and the resultant refrigerant is discharged therefrom. The high-temperature high-pressure gas refrigerant discharged from the compressor 10 passes through the four-way valve 11 and flows into the heat source side heat exchanger 12. In the heat source side heat exchanger 12, the refrigerant condenses and liquefies while transferring heat to outdoor air, so that the refrigerant turns into a high-pressure liquid refrigerant. The high-pressure liquid refrigerant, which has flowed out of the heat source side heat exchanger 12, passes through the check valve 13a, flows out of the heat source unit 1, passes through the refrigerant pipe 4, and flows into the first relay unit 3a. The high-pressure liquid refrigerant, which has flowed into the first relay unit 3a, flows into the gas-liquid separator 14, passes through the expansion valve 16e, and then flows into the second relay unit 3b.
The refrigerant, which has flowed into the second relay unit 3b, is throttled by the expansion valve 16a, so that the refrigerant expands into a low-temperature, low-pressure two-phase gas-liquid refrigerant. The two-phase gas-liquid refrigerant flows into the second intermediate heat exchanger 15b, serving as an evaporator, removes heat from the heat medium circulated through the heat medium circuits, so that the refrigerant turns into a low-temperature low-pressure gas refrigerant while cooling the heat medium. The gas refrigerant, which has flowed out of the second intermediate heat exchanger 15b, passes through the expansion valve 16c, flows out of the second relay unit 3b and the first relay unit 3a, passes through the refrigerant pipe 4, and flows into the heat source unit 1. The refrigerant, which has flowed into the heat source unit 1, passes through the check valve 13d, the four-way valve 11, and the accumulator 17, and is then again sucked into the compressor 10. The expansion valves 16b and 16d are allowed to have such a small opening degree that the refrigerant does not flow through the valve and the expansion valve 16c is fully opened in order to prevent pressure loss.
Next, the flow of the heat medium in the heat medium circuits will be described.
In the cooling only operation mode, the first pump 21a is stopped and the heat medium is accordingly circulated through the pipes 5b. The second pump 21b allows the heat medium cooled by the heat source side refrigerant in the second intermediate heat exchanger 15b to flow through the pipes 5b. The heat medium, pressurized by the second pump 21b, leaving the second pump 21b passes through the flow switching valves 22 (the flow switching valve 22a and the flow switching valve 22b) and the stop valves 24 (the stop valve 24a and the stop valve 24b) and flows into the use side heat exchangers 26 (the use side heat exchanger 26a and the use side heat exchanger 26b). In each use side heat exchanger 26, the heat medium removes heat from indoor air to cool the air-conditioning target area, such as an indoor space, where the indoor unit 2 is installed.
After that, the heat medium flows out of the use side heat exchangers 26 and flows into the flow control valves 25 (the flow control valve 25a and the flow control valve 25b). At this time, each flow control valve 25 allows only the amount of heat medium required to compensate for an air conditioning load needed in the air-conditioning target area, such as an indoor space, to flow into the corresponding use side heat exchanger 26. The other heat medium flows through each of the bypasses 27 (the bypass 27a and the bypass 27b) so as to bypass the use side heat exchanger 26.
The heat medium passing through each bypass 27 does not contribute to heat exchange and merges with the heat medium leaving the corresponding use side heat exchanger 26. The resultant heat medium passes through the corresponding flow switching valve 23 (the flow switching valve 23a or the flow switching valve 23b) and flows into the second intermediate heat exchanger 15b and is then again sucked into the second pump 21b. Note that the air conditioning load needed in each air-conditioning target area, such as an indoor space, can be provided by controlling the difference between a temperature detected by the third temperature sensor 33 and a temperature detected by the fourth temperature sensor 34 at a target value.
In this case, it is unnecessary to supply the heat medium to each use side heat exchanger 26 having no thermal load (including thermo-off). Accordingly, the corresponding stop valve 24 is closed to block the passage such that the heat medium does not flow into the use side heat exchanger 26. In
(Heating Only Operation Mode)
In the heating only operation mode illustrated in
First, the flow of the heat source side refrigerant in the refrigeration cycle will be described.
A low-temperature low-pressure refrigerant is compressed into a high-temperature high-pressure gas refrigerant by the compressor 10 and the resultant refrigerant is discharged therefrom. The high-temperature high-pressure gas refrigerant discharged from the compressor 10 passes through the four-way valve 11, flows through the first connecting pipe 4a, passes through the check valve 13b, and flows out of the heat source unit 1. The high-temperature high-pressure gas refrigerant, which has flowed out of the heat source unit 1, passes through the refrigerant pipe 4 and flows into the first relay unit 3a. The high-temperature high-pressure gas refrigerant, which has flowed into the first relay unit 3a, flows into the gas-liquid separator 14 and then flows into the first intermediate heat exchanger 15a. The high-temperature high-pressure gas refrigerant, which has flowed into the first intermediate heat exchanger 15a, condenses and liquefies while transferring heat to the heat medium circulated through the heat medium circuits, so that the refrigerant turns into a high-pressure liquid refrigerant.
The high-pressure liquid refrigerant leaving the first intermediate heat exchanger 15a is throttled by the expansion valve 16d, so that the refrigerant expands into a low-temperature, low-pressure two-phase gas-liquid state. The refrigerant in the two-phase gas-liquid state, obtained by throttling through the expansion valve 16d, passes through the expansion valve 16b, flows through the refrigerant pipe 4, and then flows into the heat source unit 1. The refrigerant, which has flowed into the heat source unit 1, passes through the check valve 13c and the second connecting pipe 4b and then flows into the heat source side heat exchanger 12, serving as an evaporator. The refrigerant, which has flowed into the heat source side heat exchanger 12, removes heat from the outdoor air in the heat source side heat exchanger 12, so that the refrigerant turns into a low-temperature low-pressure gas refrigerant. The low-temperature low-pressure gas refrigerant leaving the heat source side heat exchanger 12 passes through the four-way valve 11 and the accumulator 17 and then returns to the compressor 10. The expansion valve 16a, the expansion valve 16c, and the expansion valve 16e are allowed to have such a small opening degree that the refrigerant does not flow through the valve.
Next, the flow of the heat medium in the heat medium circuits will be described.
In the heating only operation mode, the second pump 21b is stopped and the heat medium is accordingly circulated through the pipes 5a. The first pump 21a allows the heat medium heated by the heat source side refrigerant in the first intermediate heat exchanger 15a to flow through the pipes 5a. The heat medium, pressurized by the first pump 21a, leaving the first pump 21a passes through the flow switching valves 22 (the flow switching valve 22a and the flow switching valve 22b) and the stop valves 24 (the stop valve 24a and the stop valve 24b) and flows into the use side heat exchangers 26 (the use side heat exchanger 26a and the use side heat exchanger 26b). In each use side heat exchanger 26, the heat medium transfers heat to the indoor air to heat the air-conditioning target area, such as an indoor space, where the indoor unit 2 is installed.
After that, the heat medium flows out of the use side heat exchangers 26 and flows into the flow control valves 25 (the flow control valve 25a and the flow control valve 25b). At this time, each flow control valve 25 allows only the amount of heat medium required to compensate for an air conditioning load needed in the air-conditioning target area, such as an indoor space, to flow into the corresponding use side heat exchanger 26. The other heat medium flows through each of the bypasses 27 (the bypass 27a and the bypass 27b) so as to bypass the use side heat exchanger 26.
The heat medium passing through each bypass 27 does not contribute to heat exchange and merges with the heat medium leaving the corresponding use side heat exchanger 26. The resultant heat medium passes through the corresponding flow switching valve 23 (the flow switching valve 23a or the flow switching valve 23b) and flows into the first intermediate heat exchanger 15a and is then again sucked into the first pump 21a. Note that the air conditioning load needed in each air-conditioning target area, such as an indoor space, can be provided by controlling the difference between a temperature detected by the third temperature sensor 33 and a temperature detected by the fourth temperature sensor 34 at a target value.
In this case, it is unnecessary to supply the heat medium to each use side heat exchanger 26 having no thermal load (including thermo-off). Accordingly, the corresponding stop valve 24 is closed to block the passage such that the heat medium does not flow into the use side heat exchanger 26. In
(Cooling Main Operation Mode)
In the cooling main operation mode illustrated in
First, the flow of the heat source side refrigerant in the refrigeration cycle will be described.
A low-temperature low-pressure refrigerant is compressed into a high-temperature high-pressure gas refrigerant by the compressor 10 and the resultant refrigerant is discharged therefrom. The high-temperature high-pressure gas refrigerant discharged from the compressor 10 passes through the four-way valve 11 and flows into the heat source side heat exchanger 12. In the heat source side heat exchanger 12, the refrigerant condenses while transferring heat to the outdoor air, so that the refrigerant turns into a two-phase gas-liquid refrigerant. The two-phase gas-liquid refrigerant, which has flowed out of the heat source side heat exchanger 12, passes through the check valve 13a, flows out of the heat source unit 1, passes through the refrigerant pipe 4, and flows into the first relay unit 3a. The two-phase gas-liquid refrigerant, which has flowed into the first relay unit 3a, flows into the gas-liquid separator 14, where the refrigerant is separated into a gas refrigerant and a liquid refrigerant. The resultant refrigerants flow into the second relay unit 3b.
The gas refrigerant, obtained by separation through the gas-liquid separator 14, flows into the first intermediate heat exchanger 15a. The gas refrigerant, which has flowed into the first intermediate heat exchanger 15a, condenses and liquefies while transferring heat to the heat medium circulated through the heat medium circuit, so that the refrigerant turns into a liquid refrigerant. The liquid refrigerant, which has flowed out of the first intermediate heat exchanger 15a, passes through the expansion valve 16d. On the other hand, the liquid refrigerant, obtained by separation through the gas-liquid separator 14, passes through the expansion valve 16e and merges with the liquid refrigerant leaving the expansion valve 16d after condensation and liquefaction in the first intermediate heat exchanger 15a. The resultant refrigerant is throttled by the expansion valve 16a, so that the refrigerant expands into a low-temperature, low-pressure two-phase gas-liquid refrigerant. The refrigerant flows into the second intermediate heat exchanger 15b.
The two-phase gas-liquid refrigerant removes heat from the heat medium circulated through the heat medium circuit in the second intermediate heat exchanger 15b, serving as an evaporator, so that the refrigerant turns into a low-temperature low-pressure gas refrigerant while cooling the heat medium. The gas refrigerant, which has flowed out of the second intermediate heat exchanger 15b, passes through the expansion valve 16c, flows out of the second relay unit 3b and the first relay unit 3a, passes through the refrigerant pipe 4, and flows into the heat source unit 1. The refrigerant, which has flowed into the heat source unit 1, passes through the check valve 13d, the four-way valve 11, and the accumulator 17, and is then again sucked into the compressor 10. The expansion valve 16b is allowed to have such a small opening degree that the refrigerant does not flow through the valve and the expansion valve 16c is fully opened in order to prevent pressure loss.
Next, the flow of the heat medium in the heat medium circuits will be described.
In the cooling main operation mode, both the first pump 21a and the second pump 21b are driven and the heat medium is accordingly circulated through the pipes 5a and 5b. The first pump 21a allows the heat medium heated by the heat source side refrigerant in the first intermediate heat exchanger 15a to flow through the pipes 5a. The second pump 21b allows the heat medium cooled by the heat source side refrigerant in the second intermediate heat exchanger 15b to flow through the pipes 5b.
The heat medium, pressurized by the first pump 21a, leaving the first pump 21a passes through the flow switching valve 22a and the stop valve 24a, and then flows into the use side heat exchanger 26a. The heat medium transfers heat to the indoor air in the use side heat exchanger 26a to heat the air-conditioning target area, such as an indoor space, where the indoor unit 2 is installed. In addition, the heat medium, pressurized by the second pump 21b, leaving the second pump 21b passes through the flow switching valve 22b and the stop valve 24b, and then flows into the use side heat exchanger 26b. The heat medium removes heat from the indoor air in the use side heat exchanger 26b to cool the air-conditioning target area, such as an indoor space, where the indoor unit 2 is installed.
The heat medium, used for heating, flows into the flow control valve 25a. At this time, the flow control valve 25a allows only the amount of heat medium required to compensate for an air conditioning load needed in the air-conditioning target area to flow into the use side heat exchanger 26a. The other heat medium flows through the bypass 27a so as to bypass the use side heat exchanger 26a. The heat medium passing through the bypass 27a does not contribute to heat exchange and merges with the heat medium leaving the use side heat exchanger 26a. The resultant heat medium passes through the flow switching valve 23a and flows into the first intermediate heat exchanger 15a and is then again sucked into the first pump 21a.
Similarly, the heat medium, used for cooling, flows into the flow control valve 25b. At this time, the flow control valve 25b allows only the amount of heat medium required to compensate for an air conditioning load needed in the air-conditioning target area to flow into the use side heat exchanger 26b. The other heat medium flows through the bypass 27b so as to bypass the use side heat exchanger 26b. The heat medium passing through the bypass 27b does not contribute to heat exchange and merges with the heat medium leaving the use side heat exchanger 26b. The resultant heat medium passes through the flow switching valve 23b and flows into the second intermediate heat exchanger 15b and is then again sucked into the second pump 21b.
Throughout this mode, the flow switching valves 22 (the flow switching valve 22a and the flow switching valve 22b) and the flow switching valves 23 (the flow switching valve 23a and the flow switching valve 23b) allow the warm heat medium (the heat medium used for the heating energy load) and the cold heat medium (the heat medium used for the cooling energy load) to flow into the use side heat exchanger 26a having the heating energy load and the use side heat exchanger 26b having the cooling energy load, respectively, without mixing with each other. Note that the air conditioning load needed in each air-conditioning target area, such as an indoor space, can be provided by controlling the difference between a temperature detected by the third temperature sensor 33 and a temperature detected by the fourth temperature sensor 34 at a target value.
In this case, it is unnecessary to supply the heat medium to each use side heat exchanger 26 having no thermal load (including thermo-off). Accordingly, the corresponding stop valve 24 is closed to block the passage such that the heat medium does not flow into the use side heat exchanger 26. In
(Heating Main Operation Mode)
In the heating main operation mode illustrated in
First, the flow of the heat source side refrigerant in the refrigeration cycle will be described.
A low-temperature low-pressure refrigerant is compressed into a high-temperature high-pressure gas refrigerant by the compressor 10 and the resultant refrigerant is discharged therefrom. The high-temperature high-pressure gas refrigerant discharged from the compressor 10 passes through the four-way valve 11, flows through the first connecting pipe 4a, passes through the check valve 13b, and flows out of the heat source unit 1. The high-temperature high-pressure gas refrigerant, which has flowed out of the heat source unit 1, passes through the refrigerant pipe 4 and flows into the first relay unit 3a. The high-temperature high-pressure gas refrigerant, which has flowed into the first relay unit 3a, flows into the gas-liquid separator 14 and then flows into the first intermediate heat exchanger 15a. The high-temperature high-pressure gas refrigerant, which has flowed into the first intermediate heat exchanger 15a, condenses and liquefies while transferring heat to the heat medium circulated through the heat medium circuit, so that the refrigerant turns into a high-pressure liquid refrigerant.
The high-pressure liquid refrigerant leaving the first intermediate heat exchanger 15a is throttled by the expansion valve 16d, so that the refrigerant expands into a low-temperature, low-pressure two-phase gas-liquid state. The refrigerant in the two-phase gas-liquid state, obtained by throttling through the expansion valve 16d, is divided into a flow to the expansion valve 16a and a flow to the expansion valve 16b. As regards the refrigerant flowing through the expansion valve 16a, the refrigerant is further expanded by the expansion valve 16a, so that the refrigerant turns into a low-temperature, low-pressure two-phase gas-liquid refrigerant. The resultant refrigerant flows into the second intermediate heat exchanger 15b, serving as an evaporator. The refrigerant, which has flowed into the second intermediate heat exchanger 15b, removes heat from the heat medium in the second intermediate heat exchanger 15b, so that the refrigerant turns into a low-temperature low-pressure gas refrigerant. The low-temperature low-pressure gas refrigerant leaving the second intermediate heat exchanger 15b passes through the expansion valve 16c.
As regards the refrigerant flowing through the expansion valve 16b after being throttled through the expansion valve 16d, the refrigerant merges with the refrigerant which has passed through the second intermediate heat exchanger 15b and the expansion valve 16c, so that the low-temperature low-pressure refrigerant exhibits a higher quality. The resultant refrigerant flows out of the second relay unit 3b and the first relay unit 3a, passes through the refrigerant pipe 4, and flows into the heat source unit 1. The refrigerant, which has flowed into the heat source unit 1, passes through the check valve 13c and the second connecting pipe 4b and flows into the heat source side heat exchanger 12, serving as an evaporator. The refrigerant, which has flowed into the heat source side heat exchanger 12, removes heat from the outdoor air in the heat source side heat exchanger 12, so that the refrigerant turns into a low-temperature low-pressure gas refrigerant. The low-temperature low-pressure gas refrigerant leaving the heat source side heat exchanger 12 flows through the four-way valve 11 and the accumulator 17 and then returns to the compressor 10. The expansion valve 16e is allowed to have such a small opening degree that the refrigerant does not flow through the valve.
Next, the flow of the heat medium in the heat medium circuits will be described.
In the heating main operation mode, both the first pump 21a and the second pump 21b are driven and the heat medium is accordingly circulated through the pipes 5a and 5b. The first pump 21a allows the heat medium heated by the heat source side refrigerant in the first intermediate heat exchanger 15a to flow through the pipes 5a. The second pump 21b allows the heat medium cooled by the heat source side refrigerant in the second intermediate heat exchanger 15b to flow through the pipes 5b.
The heat medium, pressurized by the first pump 21a, leaving the first pump 21a passes through the flow switching valve 22a and the stop valve 24a and then flows into the use side heat exchanger 26a. The heat medium transfers heat to the indoor air in the use side heat exchanger 26a to heat the air-conditioning target area, such as an indoor space, where the indoor unit 2 is installed. In addition, the heat medium, pressurized by the second pump 21b, leaving the second pump 21b passes through the flow switching valve 22b and the stop valve 24b and then flows into the use side heat exchanger 26b. The heat medium removes heat from the indoor air in the use side heat exchanger 26b to cool the air-conditioning target area, such as an indoor space, where the indoor unit 2 is installed.
The heat medium leaving the use side heat exchanger 26a flows into the flow control valve 25a. At this time, the flow control valve 25a allows only the amount of heat medium required to compensate for an air conditioning load needed in the air-conditioning target area, such as an indoor space, to flow into the use side heat exchanger 26a. The other heat medium flows through the bypass 27a so as to bypass the use side heat exchanger 26a. The heat medium passing through the bypass 27a does not contribute to heat exchange and merges with the heat medium leaving the use side heat exchanger 26a. The resultant heat medium passes through the flow switching valve 23a and flows into the first intermediate heat exchanger 15a and is then again sucked into the first pump 21a.
Similarly, the heat medium leaving the use side heat exchanger 26b flows into the flow control valve 25b. At this time, the flow control valve 25b allows only the amount of heat medium required to compensate for an air conditioning load needed in the air-conditioning target area, such as an indoor space, to flow into the use side heat exchanger 26b. The other heat medium flows through the bypass 27b so as to bypass the use side heat exchanger 26b. The heat medium passing through the bypass 27b does not contribute to heat exchange and merges with the heat medium leaving the use side heat exchanger 26b. The resultant heat medium passes through the flow switching valve 23b and flows into the second intermediate heat exchanger 15b and is then again sucked into the second pump 21b.
Throughout this mode, the flow switching valves 22 (the flow switching valve 22a and the flow switching valve 22b) and the flow switching valves 23 (the flow switching valve 23a and the flow switching valve 23b) allow the warm heat medium and the cold heat medium to flow into the use side heat exchanger 26a having the heating energy load and the use side heat exchanger 26b having the cooling energy load, respectively, without mixing with each other. Note that the air conditioning load needed in each air-conditioning target area, such as an indoor space, can be provided by controlling the difference between a temperature detected by the third temperature sensor 33 and a temperature detected by the fourth temperature sensor 34 at a target value.
In this case, it is unnecessary to supply the heat medium to each use side heat exchanger 26 having no thermal load (including thermo-off). Accordingly, the corresponding stop valve 24 is closed to block the passage such that the heat medium does not flow into the use side heat exchanger 26. In
(Process of Detecting Abnormal Reduction in Flow Rate of Heat Medium)
A process of detecting an excessive reduction in flow rate of the heat medium in any heat medium circuit in the air-conditioning apparatus 100 according to Embodiment 1 caused by, for example, blockage of pipes during the cooling operation will now be described.
In the following description, let TE denote the temperature (e.g., an evaporating temperature that is the temperature of the refrigerant passing through the refrigerant passage when the heat source side refrigerant has a low temperature) of the heat source side refrigerant passing through the refrigerant passage of the intermediate heat exchanger 15, let T32 denote the heat medium inlet side temperature related to the intermediate heat exchanger 15 detected by the second temperature sensor 32, and let T31 denote the heat medium outlet side temperature related to the intermediate heat exchanger 15 detected by the first temperature sensor 31.
A typical air-conditioning apparatus is designed such that a temperature efficiency ratio εe is approximately 0.7 (70%). The temperature efficiency ratio εe is the ratio of the difference (T32−TE) between the heat medium inlet side temperature related to the intermediate heat exchanger 15 and the refrigerant temperature in the intermediate heat exchanger 15 to the difference (T32−T31) between the heat medium inlet side temperature related to the intermediate heat exchanger 15 and the heat medium outlet side temperature related thereto. Accordingly, for example, when the heat medium flows through the heat medium circuit (or the heat medium passage of the intermediate heat exchanger 15) at a normal flow rate, the heat medium temperature during the cooling operation is indicated by LINE (1) in
As the flow rate of the heat medium decreases, however, the heat medium outlet side temperature related to the intermediate heat exchanger 15 approaches the refrigerant temperature because the amount of heat exchanged between the heat medium and the refrigerant increases. Consequently, the temperature efficiency ratio εe tends to be large as indicated by LINE (2) in
The above-described fact reveals that the temperature efficiency ratio εe has a proper range. When the temperature efficiency ratio εe exceeds the proper range, therefore, the flow of the heat medium in the heat medium circuit can be determined as abnormal. This tendency is generally common to heat exchange between the heat medium and air. Accordingly, for example, abnormality in flow rate of the heat medium can be determined on the basis of the sucked air temperature, Ta, detected by the eighth temperature sensor 39. Although
For comparison, a reference temperature efficiency ratio εthe is set based on measurement or the like in advance. The reference temperature efficiency ratio εthe is the reference of the temperature efficiency ratio obtained when the heat medium flows in a normal state. Although the reference temperature efficiency ratio εthe may be constant, the reference temperature efficiency ratio εthe increases or decreases depending on, for example, the flow rate (flow rate per unit time) of the heat medium. To perform the detecting process, therefore, the controller 60 may set the reference temperature efficiency ratio εthe depending on the flow rate by, for example, estimating the flow rate of the heat medium on the basis of a rotation speed of the pump 21.
The controller 60, therefore, calculates an actual temperature efficiency ratio (hereinafter, referred to as the “actual temperature efficiency ratio”) εe=(T32−T31)/(T32−TE) on the basis of the refrigerant temperature TE, the heat medium outlet side temperature T31, and the heat medium inlet side temperature T32 detected actually. Then, the controller 60 determines whether the difference between the actual temperature efficiency ratio εe and the reference temperature efficiency ratio εthe is within a predetermined range. When determining that the difference is within the predetermined range, the controller 60 determines that the heat medium is circulated at a normal flow rate through the heat medium circuit without a reduction in flow rate due to, for example, the leakage of the heat medium or a failure of the pump 21.
Furthermore, an excessive reduction in flow rate of the heat medium in the heat medium circuit of the air-conditioning apparatus 100 during the heating operation caused by, for example, the leakage of the refrigerant is similarly detected. For example, let TC denote the temperature (e.g., a condensing temperature that is the temperature of the refrigerant passing through the refrigerant passage when the refrigerant has a high temperature) of the refrigerant passing through the refrigerant passage of the intermediate heat exchanger 15.
The controller 60 calculates an actual temperature efficiency ratio εc=(T31−T32)/(TC−T32) on the basis of the refrigerant temperature TC, the heat medium outlet side temperature T31, and the heat medium inlet side temperature T32 detected actually. When determining that the difference between the actual temperature efficiency ratio εc and a reference temperature efficiency ratio εthc is within a predetermined range, the controller 60 determines that the heat medium is circulated at a normal flow rate through the heat medium circuit.
For example, while the operation of the refrigeration cycle is stopped, the refrigerant temperature TE is not detected. Accordingly, it is difficult to calculate the actual temperature efficiency ratio εe on the basis of the refrigerant temperature TE in order to determine an abnormal flow rate of the heat medium. As described above, therefore, a change in temperature efficiency ratio for heat exchange between the heat medium and air with decreasing heat medium flow rate is used for determination based on the sucked air temperature Ta detected by the eighth temperature sensor 39. The sucked air temperature Ta may be the mean of sucked air temperatures related to the indoor units 2 performing the cooling operation. Alternatively, the sucked air temperature related to any of the indoor units 2 performing the cooling operation may be representatively used as the sucked air temperature Ta.
The controller 60 calculates an actual temperature efficiency ratio εa=(T31−T32)/(Ta−T32) on the basis of the sucked air temperature Ta, the heat medium outlet side temperature T31, and the heat medium inlet side temperature T32, and determines whether the difference between the actual temperature efficiency ratio εa and a reference temperature efficiency ratio εtha is within a predetermined range. When determining that the difference is within the predetermined range, the controller 60 determines that the heat medium flows at a normal flow rate.
In STEP 3, the controller 60 determines whether the rotation speed of the pump 21 is at or above a given rotation speed. The given rotation speed used as a reference for the pump 21 is determined in advance. Since the lengths of the pipes (for example, the total length thereof), the diameters of the pipes, and the like in the heat medium circuit may vary from air-conditioning apparatus 100 to another, the given rotation speed may be determined on the basis of the configuration or the like of the air-conditioning apparatus 100.
When determining that the rotation speed of the pump 21 is at or above the given rotation speed, the controller 60 proceeds to STEP 4. On the other hand, when determining that it is not at or above the given rotation speed (i.e., below the given rotation speed), the controller 60 proceeds to STEP 8. In STEP 4, the controller 60 sets the reference temperature efficiency ratios εthe and εtha depending on a designated rotation speed of the pump 21 and then proceeds to STEP 5.
In STEP 5, the controller 60 determines whether the operation is in a thermo-off state (in which the operation is not performed in the refrigeration cycle). When determining that the operation is in the thermo-off state, the controller 60 proceeds to STEP 6. On the other hand, when determining that the operation is not in the thermo-off state, the controller 60 proceeds to STEP 7.
In STEP 6, since the operation is not performed in the refrigeration cycle, the controller 60 calculates the actual temperature efficiency ratio εa on the basis of the sucked air temperature Ta, the heat medium outlet side temperature T31, and the heat medium inlet side temperature T32 as described above, and then compares the actual temperature efficiency ratio εa with the reference temperature efficiency ratio εtha set in advance. When determining that the difference between the temperature efficiency ratios is less than a given value ka1, the controller 60 proceeds to STEP 8. On the other hand, when determining that the difference between the actual temperature efficiency ratio εa and the reference temperature efficiency ratio εtha is greater than or equal to the given value, the controller 60 determines there is abnormality and proceeds to STEP 14.
On the other hand, in STEP 7, since the operation is performed in the refrigeration cycle, the controller 60 calculates the actual temperature efficiency ratio εe on the basis of the refrigerant temperature TE, the heat medium outlet side temperature T31, and the heat medium inlet side temperature T32, and then compares the actual temperature efficiency ratio εe with the set reference temperature efficiency ratio εthe. When determining that the difference therebetween is less than a given value ke1, the controller 60 proceeds to STEP 8. When determining that the difference between the actual temperature efficiency ratio εe and the reference temperature efficiency ratio εthe is greater than or equal to the given value, the controller 60 determines there is abnormality and proceeds to STEP 14.
In STEP 8, the controller 60 determines whether the rotation speed of the pump 21 is at or below a given rotation speed. This predetermined rotation speed used as a reference for the pump 21 is determined in advance. When determining that the rotation speed of the pump 21 is at or below the given rotation speed, the controller 60 proceeds to STEP 9. When determining that the ration speed of the pump 21 is not at or below the given rotation speed (i.e., the rotation speed of the pump 21 is above the given rotation speed), the controller 60 proceeds to STEP 12. In STEP 9, the controller 60 determines whether the operation is in the thermo-off state. When determining that the operation is in the thermo-off state, the controller 60 proceeds to STEP 10. When determining that the operation is not in the thermo-off state, the controller 60 proceeds to STEP 11.
In STEP 10, since the operation is not performed in the refrigeration cycle, the controller 60 calculates the actual temperature efficiency ratio εa on the basis of the sucked air temperature Ta, the heat medium outlet side temperature T31, and the heat medium inlet side temperature T32 as described above, and then compares the actual temperature efficiency ratio εa with the reference temperature efficiency ratio εtha set in advance. When determining that the difference between these ratios is less than a given value ka2, the controller 60 proceeds to STEP 12. On the other hand, when determining that the difference between the actual temperature efficiency ratio εa and the reference temperature efficiency ratio εtha is greater than or equal to the given value, the controller 60 determines there is abnormality and proceeds to STEP 14.
On the other hand, in STEP 11, since the operation is performed in the refrigeration cycle, the controller 60 calculates the actual temperature efficiency ratio εe on the basis of the refrigerant temperature TE, the heat medium outlet side temperature T31, and the heat medium inlet side temperature T32, and then compares the actual temperature efficiency ratio εe with the set reference temperature efficiency ratio εthe. When determining that the difference between these ratios is less than a given value ke2, the controller 60 proceeds to STEP 12. When determining that the difference between the actual temperature efficiency ratio εe and the reference temperature efficiency ratio εthe is greater than or equal to the given value, the controller 60 determines there is abnormality and proceeds to STEP 14.
In STEP 12, the controller 60 determines whether to continue the air conditioning operation. When determining the continuation, the controller 60 returns to STEP 2 and repeats the determination. When determining the discontinuation of the air conditioning operation, the controller 60 proceeds to STEP 13 and stops the air conditioning operation, thus terminating the process.
In STEP 23, the controller 60 determines whether the rotation speed of the pump 21 is at or above a given rotation speed. The given rotation speed used as a reference for the pump 21 is determined in advance. Since the lengths of the pipes (for example, the total length thereof), the diameters of the pipes, and the like in the heat medium circuit may vary from air-conditioning apparatus 100 to another, the given rotation speed may be determined on the basis of the configuration or the like of the air-conditioning apparatus 100.
When determining that the rotation speed of the pump 21 is at or above the given rotation speed, the controller 60 proceeds to STEP 24. On the other hand, when determining that the rotation speed of the pump 21 is not at or above the given rotation speed (i.e., below the given rotation speed), the controller 60 proceeds to STEP 28. In STEP 24, the controller 60 sets the reference temperature efficiency ratios εthc and εtha depending on a designated rotation speed of the pump 21 and proceeds to STEP 25.
In STEP 25, the controller 60 determines whether the operation is in the thermo-off state (in which the operation is not performed in the refrigeration cycle). When determining that the operation is in the thermo-off state, the controller 60 proceeds to STEP 26. When determining that the operation is not in the thermo-off state, the controller 60 proceeds to STEP 27.
In STEP 26, since the operation is not performed in the refrigeration cycle, the controller 60 calculates the actual temperature efficiency ratio εa on the basis of the sucked air temperature Ta, the heat medium outlet side temperature T31, and the heat medium inlet side temperature T32 as described above, and then compares the actual temperature efficiency ratio εa with the reference temperature efficiency ratio εtha set in advance. When determining that the difference between these ratios is less than the given value ka1, the controller 60 proceeds to STEP 28. When determining that the difference between the actual temperature efficiency ratio εa and the reference temperature efficiency ratio εtha is greater than or equal to the given value, the controller 60 determines there is abnormality and proceeds to STEP 34.
On the other hand, in STEP 27, since the operation is performed in the refrigeration cycle, the controller 60 calculates the actual temperature efficiency ratio εc on the basis of the refrigerant temperature TC, the heat medium outlet side temperature T31, and the heat medium inlet side temperature T32, and then compares the actual temperature efficiency ratio εc with the set reference temperature efficiency ratio εthc. When determining that the difference between these ratios is less than a given value kc1, the controller 60 proceeds to STEP 28. When determining that the difference between the actual temperature efficiency ratio εc and the reference temperature efficiency ratio εthc is greater than or equal to the given value, the controller 60 determines there is abnormality and proceeds to STEP 34.
In STEP 28, the controller 60 determines whether the rotation speed of the pump 21 is at or below a given rotation speed. The predetermined rotation speed used as a reference for the pump 21 is determined in advance. When determining that the rotation speed of the pump 21 is at or below the given rotation speed, the controller 60 proceeds to STEP 29. When determining that the rotation speed of the pump 21 is not at or below the given rotation speed (i.e., the rotation speed of the pump 21 is above the given rotation speed), the controller 60 proceeds to STEP 32. In STEP 29, the controller 60 determines whether the operation is in the thermo-off state. When determining that the operation is in the thermo-off state, the controller 60 proceeds to STEP 30. When determining that the operation is not in the thermo-off state, the controller 60 proceeds to STEP 31.
In STEP 30, since the operation is not performed in the refrigeration cycle, the controller 60 calculates the actual temperature efficiency ratio εa on the basis of the sucked air temperature Ta, the heat medium outlet side temperature T31, and the heat medium inlet side temperature T32 as described above, and then compares the actual temperature efficiency ratio εa with the reference temperature efficiency ratio εtha set in advance. When determining that the difference between these ratios is less than the given value ka2, the controller 60 proceeds to STEP 32. When determining that the difference between the actual temperature efficiency ratio εa and the reference temperature efficiency ratio εtha is greater than or equal to the given value, the controller 60 determines there is abnormality and proceeds to STEP 34.
On the other hand, in STEP 31, since the operation is performed in the refrigeration cycle, the controller 60 calculates the actual temperature efficiency ratio εc on the basis of the refrigerant temperature TC, the heat medium outlet side temperature T31, and the heat medium inlet side temperature T32, and then compares the actual temperature efficiency ratio εc with the set reference temperature efficiency ratio εthc. When determining that the difference between these ratios is less than a given value kc2, the controller 60 proceeds to STEP 32. When determining that the difference between the actual temperature efficiency ratio εc and the reference temperature efficiency ratio εthc is greater than or equal to the given value, the controller 60 determines there is abnormality and proceeds to STEP 34.
In STEP 32, the controller 60 determines whether to continue the air conditioning operation. When determining the continuation, the controller 60 returns to STEP 22 and repeats the determination. When determining the discontinuation of the air conditioning operation, the controller 60 proceeds to STEP 33 and stops the air conditioning operation, thus terminating the process.
For example, when a cooling and heating mixed operation is performed, the heat medium system is separated into a heat medium system including the pipes 5a and a heat medium system including the pipes 5b. In this case, an abnormal flow rate of the heat medium is determined in each system. When abnormality is determined in one system, for example, the circulation of the heat medium is stopped. In the other system in which no abnormality is determined to be present, the pump 21 may be driven to continue the air conditioning operation.
When the abnormal flow rate of the heat medium is determined by the above-described process and at least one pump 21 is stopped, the controller 60 allows the annunciator 62 to provide information about the occurrence of abnormality.
While the operation is being continued, the information about the occurrence of abnormality is provided to the outside in this manner to prompt maintenance, for example. This allows an abnormal condition to be immediately dealt with, so that a process of restoration to a normal condition can be performed at once.
As described above, in the air-conditioning apparatus 100 according to Embodiment 1, the controller 60 determines whether abnormality in flow rate has occurred in the heat medium circuit on the basis of the temperature efficiency ratio related to heat exchange by the intermediate heat exchanger 15 or the use side heat exchanger 26. Accordingly, an abnormal flow rate can be determined accurately and efficiently. For example, in case of the leakage of the heat medium, an increase in load to the pump 21 caused by a reduction in flow rate can be expected to be immediately dealt with. Furthermore, in case of breakdown or the like of the pump 21, the occurrence of breakdown or the like can be expected to be immediately detected. In addition, since an abnormal flow rate can be determined using the sensors typically used for air conditioning control, determination or the like can be achieved in a cost-efficient manner.
In Embodiment 1 described above, the actual temperature efficiency ratio εa is calculated using the heat medium inlet side temperature T32 related to the intermediate heat exchanger 15 detected by the second temperature sensor 32 and the heat medium outlet side temperature T31 related to the intermediate heat exchanger 15 detected by the first temperature sensor 31. The calculation is not limited to this manner. For example, the actual temperature efficiency ratio εa may be calculated using an incoming heat medium temperature related to the use side heat exchanger 26 detected by the third temperature sensor 33 and an outgoing heat medium temperature related to the use side heat exchanger 26 detected by the fourth temperature sensor 34.
In Embodiment 1 described above, for example, the first intermediate heat exchanger 15a is used as a heat exchanger for heating the heat medium and the second intermediate heat exchanger 15b is used as a heat exchanger for cooling the heat medium. The configuration of the refrigeration cycle is not limited to that in Embodiment 1. For example, the first intermediate heat exchanger 15a and the second intermediate heat exchanger 15b can be configured to be capable of heating and cooling the heat medium. In such a configuration, both the first intermediate heat exchanger 15a and the second intermediate heat exchanger 15b can be used as heating devices in the heating only operation mode or cooling devices in the cooling only operation mode.
During the cooling and heating mixed operation, if the heating operation is performed in one system in which the pump 21 is stopped because abnormality in flow rate has been determined, the cooling operation performed in the other system may be switched to the heating operation (and vice versa). As regards a criterion for the determination as to whether to switch between the operations, for example, the operation designated first can be preferentially performed, or alternatively the operation with a larger total amount of heat exchanged in the use side heat exchangers 26 can be preferentially performed.
Although the air-conditioning apparatus 100 including at least two intermediate heat exchangers 15 for achieving the cooling and heating mixed operation or the like has been described in Embodiment 1, the present invention can be applied to, for example, an air-conditioning apparatus including a single intermediate heat exchanger. Furthermore, the invention can be applied to an air-conditioning apparatus including a single indoor unit 2.
Although the heat medium is heated or cooled using the refrigeration cycle through which the heat source side refrigerant is circulated in Embodiment 1, the heat medium may be heated or cooled by any device.
For example, if air enters the heat medium circuit, the work load of the pump 21 would decrease depending on the amount of air entered. When the supply of the same amount of power as that in a state where no air enters the heat medium circuit is provided, therefore, the rotation speed of the pump 21 would tend to increase. In particular, if the amount of air entered is at or above a given value, the pump 21 would be driven at an actual rotation speed which would never be measured in the normal state and the relationship between the command rotation speed and the actual rotation speed would be at a position in an abnormal range in
Data indicating the relationship between the command rotation speed and the actual rotation speed mapped in the normal range and that mapped in the abnormal range is stored in the controller 60 in advance in
As described above, according to Embodiment 4, an operation state is directly monitored on the basis of the actual rotation speed of the pump 21 detected by the rotation speed detecting sensor 41 to determine whether abnormality has occurred, and the pump 21 can be controlled. Thus, whether abnormality has occurred can be accurately determined. In addition, for example, since the entry of air into a heat medium circulating circuit can be determined before the pump 21 is damaged, such a problem can be immediately dealt with.
The above-described characteristics are taken into consideration, an upper limit temperature at which the pump 21 is free from damage or the like is determined in advance through testing or the like, and data indicating the limit value is stored in the controller 60. The controller 60 determines whether a temperature detected by the tenth temperature sensor 42 disposed near the heat medium inlet or outlet of the pump 21 has exceeded the limit value at regular time intervals. When determining that the temperature has exceeded the limit value and such a state is accordingly abnormal, for example, the controller 60 stops the operation of the relay unit 3 (or stops the pump 21) and allows the annunciator 62 to provide information about such a state.
The tenth temperature sensor 42 may be disposed near any one or each of the heat medium inlet and outlet of the pump 21. Alternatively, the tenth temperature sensor 42 may be disposed at a position where the sensor is easily placed inside the pump 21 and the internal temperature of the pump 21 may be directly detected.
As described above, according to Embodiment 5, the temperature of the pump 21 is monitored on the basis of a temperature detected by the tenth temperature sensor 42 to determine whether abnormality has occurred, and the pump 21 can be controlled. Thus, whether abnormality has occurred can be accurately determined. In addition, for example, since the entry of air into the heat medium circulating device can be determined before the pump 21 is damaged, such a problem can be immediately dealt with.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP2012/000258 | 1/18/2012 | WO | 00 | 3/27/2014 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2013/108290 | 7/25/2013 | WO | A |
| Number | Name | Date | Kind |
|---|---|---|---|
| 20040145119 | Nakamura | Jul 2004 | A1 |
| 20060018677 | Kim | Jan 2006 | A1 |
| 20110192184 | Yamashita | Aug 2011 | A1 |
| 20110302941 | Takata | Dec 2011 | A1 |
| Number | Date | Country |
|---|---|---|
| 1 707 886 | Jan 2006 | EP |
| 1707886 | Oct 2006 | EP |
| 2006-266587 | Oct 2006 | JP |
| 2009-243828 | Oct 2009 | JP |
| 2009243828 | Oct 2009 | JP |
| 2010-091181 | Apr 2010 | JP |
| 2010-127568 | Jun 2010 | JP |
| 2010127568 | Jun 2010 | JP |
| 2010-223542 | Oct 2010 | JP |
| 2011-226704 | Nov 2011 | JP |
| 2010049998 | May 2010 | WO |
| 2010109617 | Sep 2010 | WO |
| Entry |
|---|
| Office Action dated Dec. 21, 2015 in the corresponding CN application No. 201280062523.8 (with English translation). |
| Extended European Search Report dated Sep. 14, 2015 in the corresponding EP application No. 12866077.6. |
| Office Action dated Mar. 24, 2015 in corresponding JP Application No. 2013-554069 (with English translation). |
| International Search Report of the International Searching Authority dated Apr. 24, 2012 for the corresponding international application No. PCT/JP2012/000258. |
| Number | Date | Country | |
|---|---|---|---|
| 20140305152 A1 | Oct 2014 | US |
