Patent Application
20250027659
The present disclosure relates to a heat pump apparatus.
A heat pump cycle apparatus disclosed in PTL 1 below adds a target calculation temperature T1 to a second hot water storage tank temperature Ts2 to calculate a target outgoing hot water temperature Tea during an operation of heating water stored in a hot water storage tank to a predetermined temperature and controls a rotation speed of a compressor such that an outgoing hot water temperature Te of a use-side heat exchanger is equal to the target outgoing hot water temperature Tea.
A tank unit to be used in combination with a heat pump apparatus includes a water heat exchanger for exchanging heat between a heat medium and water stored in a hot water storage tank. There are a plurality of types of tank units having water heat exchangers different in structure. When a tank unit different in structure of water heat exchanger is combined with the heat pump apparatus, a hot water storage operation might not be carried out appropriately.
The present disclosure has been made to solve the above-described problem, and has an object to provide a heat pump apparatus that can be combined with a plurality of types of tank units different in structure of water heat exchanger.
A heat pump apparatus according to the present disclosure is for supplying a heat medium to a tank unit including a water heat exchanger to exchange heat between the heat medium and water stored in a hot water storage tank. The heat pump apparatus includes: a compressor to compress refrigerant; a heat medium heat exchanger to exchange heat between the refrigerant and the heat medium; heat transfer performance determination means for determining heat transfer performance of the water heat exchanger; and compressor control means for adjusting a rotation speed of the compressor during a hot water storage operation, which is an operation for increasing a temperature of the water in the hot water storage tank. The compressor control means is configured to adjust the rotation speed of the compressor during the hot water storage operation such that the rotation speed of the compressor when the heat transfer performance of the water heat exchanger is determined to be relatively low is higher than the rotation speed of the compressor when the heat transfer performance of the water heat exchanger is determined to be relatively high.
According to the present disclosure, a heat pump apparatus that can be combined with a plurality of types of tank units different in structure of water heat exchanger can be provided.
Hereinafter, embodiments will be described with reference to the drawings. Common or corresponding elements in the respective drawings are denoted by the same reference characters, and description will be simplified or omitted. In the following description, the expression “water” or “hot water” means liquid water in principle, and shall include cold water to boiling water.
A compressor 4 that compresses refrigerant, a heat medium heat exchanger 5, an expansion valve 6, an evaporator 7, a first controller 9, and a blower 10 are provided inside an enclosure 43 of the heat pump apparatus 2. A substance to be used as the refrigerant is not limited, and CO2, HFC, HC, HFO, or the like, for example, can be used. The heat medium heat exchanger 5 includes a primary flow passage 5a and a secondary flow passage 5b. Heat is exchanged between the refrigerant passing through the primary flow passage 5a and heat medium passing through the secondary flow passage 5b. Liquid to be used as the heat medium may be water or brine other than water. The compressor 4, the primary flow passage 5a, the expansion valve 6, and the evaporator 7 are connected via a refrigerant pipe to form a refrigerant circuit.
The expansion valve 6 is equivalent to a decompression device that decompresses and expands high-pressure refrigerant. The evaporator 7 exchanges heat between air outside the room taken in from the outside of the heat pump apparatus 2 and the refrigerant to evaporate the refrigerant. The blower 10 blows air such that outside air flows passing through the evaporator 7.
A hot water storage tank 11, a water heat exchanger 12, a heat medium pump 13, a water pump 14, and a flow passage switching valve 15 are provided inside an enclosure 44 of the tank unit 3.
The hot water storage tank 11 is a container for storing hot water. The hot water storage tank 11 is covered by a heat insulation material not shown. An outlet 17 is provided at a lower part of the hot water storage tank 11. An inlet 18 is provided for the hot water storage tank 11 at a position higher than the outlet 17. The hot water storage tank 11 has a cylindrical outer shape, for example.
The water heat exchanger 12 includes a primary flow passage 12a and a secondary flow passage 12b. Heat is exchanged between the heat medium passing through the primary flow passage 12a and water passing through the secondary flow passage 12b. A water feed passage 19 connects the outlet 17 to an entrance of the secondary flow passage 12b. A water return passage 20 connects an exit of the secondary flow passage 12b to the inlet 18. The water pump 14 is provided halfway through the water return passage 20. A water circuit 21 is formed by the water feed passage 19, the secondary flow passage 12b, and the water return passage 20. When the water pump 14 is actuated, water in the water circuit 21 flows.
A water supply pipe 22 is connected to a lower part of the hot water storage tank 11. The water supply pipe 22 extends to the outside of the tank unit 3. Water supplied from a water source such as waterworks, for example, passes through the water supply pipe 22 to flow into the hot water storage tank 11. A hot water supply pipe 23 is connected to an upper part of the hot water storage tank 11. The hot water supply pipe 23 extends to the outside of the tank unit 3. Hot water stored in the hot water storage tank 11 passes through the hot water supply pipe 23 to be supplied to a hot water supply end such as a shower, tap, or bathtub, for example. When hot water is flown out of the hot water storage tank 11 through the hot water supply pipe 23, the same quantity of water flows into the hot water storage tank 11 through the water supply pipe 22. As a result, the hot water storage tank 11 is maintained in a full-water state.
As in the illustrated example, a room-heating apparatus 24 for heating a room may be connected to the tank unit 3. In the following description, an operation of circulating the heat medium to the room-heating apparatus 24 will be referred to as a room-heating operation. The room-heating apparatus 24 is installed in the room. The room-heating apparatus 24 may include at least one of a floor heating panel installed under the floor, a radiator installed in a wall surface in the room, a panel heater, and a fan convector, for example.
A branch part 25 is formed on a passage upstream of an intake of the heat medium pump 13. A passage 26 connects the exit of the primary flow passage 12a of the water heat exchanger 12 to the branch part 25. The flow passage switching valve 15 is a valve for switching a circuit in which the heat medium flows. The flow passage switching valve 15 has an a port which is an inlet, a c port which is an outlet, and a d port which is an outlet.
A passage 27 and a passage 28 connect the heat pump apparatus 2 to the tank unit 3. The passage 27 connects a discharge port of the heat medium pump 13 to an entrance of the secondary flow passage 5b of the heat medium heat exchanger 5. The passage 28 connects an exit of the secondary flow passage 5b to the a port of the flow passage switching valve 15. The passage 27 and the passage 28 pass through the outside of the enclosure 43 of the heat pump apparatus 2 and the outside of the enclosure 44 of the tank unit 3. An installation place of the heat pump apparatus 2 may be distant from the installation place of the tank unit 3. A passage 29 connects the c port of the flow passage switching valve 15 to an entrance of the primary flow passage 12a of the water heat exchanger 12.
A passage 30 and a passage 31 connect the room-heating apparatus 24 to the tank unit 3. The passage 30 connects the d port of the flow passage switching valve 15 to an entrance for the heat medium of the room-heating apparatus 24. The passage 31 connects an exit for the heat medium of the room-heating apparatus 24 to the branch part 25.
A discharge temperature sensor 32 is arranged on a refrigerant pipe between the compressor 4 and the heat medium heat exchanger 5. The discharge temperature sensor 32 can detect a compressor discharge temperature which is the temperature of the refrigerant discharged from the compressor 4.
A stored hot water temperature sensor 35 is provided for the hot water storage tank 11. The stored hot water temperature sensor 35 detects the temperature of water in the hot water storage tank 11. The position at which the stored hot water temperature sensor 35 is arranged is a position higher than the outlet 17 and lower than the inlet 18.
In the following description, the temperature of the heat medium flowing into the secondary flow passage 5b of the heat medium heat exchanger 5 will be referred to as a “heat pump entrance temperature”, and the temperature of the heat medium flowing out of the secondary flow passage 5b will be referred to as a “heat pump exit temperature”.
The heat pump apparatus 2 further includes a heat pump entrance temperature sensor 37, a heat pump exit temperature sensor 38, and an outside air temperature sensor 41. The heat pump entrance temperature sensor 37 installed on the passage 27 detects the heat pump entrance temperature. The heat pump exit temperature sensor 38 installed on the passage 28 detects the heat pump exit temperature. The outside air temperature sensor 41 detects an outside air temperature which is the temperature of outdoor air.
In the present disclosure, the temperature of water flowing out of the outlet 17 of the hot water storage tank 11 to the water feed passage 19 will be referred to as a “tank flow-out temperature”. The tank flow-out temperature is equivalent to the temperature of water flowing into the secondary flow passage 12b of the water heat exchanger 12. A tank flow-out temperature sensor 39 installed on the water feed passage 19 detects the tank flow-out temperature.
In the present disclosure, the temperature of water passing through the water return passage 20 to flow into the hot water storage tank 11 from the inlet 18 will be referred to as a “tank flow-in temperature”. The tank flow-in temperature is equivalent to the temperature of water flowing out of the secondary flow passage 12b of the water heat exchanger 12 to the water return passage 20. A tank flow-in temperature sensor 40 installed on the water return passage 20 detects the tank flow-in temperature.
In the present embodiment, the hot water storage tank 11 has an uppermost part 42. The uppermost part 42 is equivalent to a portion of the hot water storage tank 11 higher than the inlet 18. An entrance of the hot water supply pipe 23 is located in the uppermost part 42. The hot water supply pipe 23 is configured to take out hot water in the uppermost part 42. The hot water in the uppermost part 42 is supplied to the outside through the hot water supply pipe 23.
In the illustrated example, a second controller 16 is arranged inside the enclosure 44 of the tank unit 3. As a modification, the second controller 16 may be arranged outside the enclosure 44, or the second controller 16 may be provided integrally with the heat pump apparatus 2.
The first controller 9 and the second controller 16 are connected to each other by wire or wirelessly such that data communication can be performed bi-directionally. The first controller 9 and the second controller 16 are equivalent to control circuitry that controls a behavior of the hot water supply system 1. At least one of the first controller 9 and the second controller 16 may have a timer function that manages the time. At least one of the first controller 9 and the second controller 16 may have a calendar function that manages the date.
In the present embodiment, the first controller 9 and the second controller 16 cooperate with each other to control the behavior of the hot water supply system 1. The present disclosure is not limited to the configuration in which the plurality of controllers cooperate with each other to control the behavior of the hot water supply system 1 as in the illustrated example, but a configuration in which the behavior of the hot water supply system 1 is controlled by a single controller may be adopted.
The hot water supply system 1 of the present embodiment includes a remote controller 50. The remote controller 50 and the second controller 16 are connected to each other by wire or wirelessly such that data communication can be performed bi-directionally. The remote controller 50 may be installed in the room. The remote controller 50 has a function of accepting handling by the user related to an operation behavior command, changing of a set value, and others. The remote controller 50 is equivalent to a human interface. Although illustration is omitted, a display that displays information concerning the state of the hot water supply system 1, a handling part such as a switch to be handled by the user, a speaker, a microphone, and the like may be mounted on the remote controller 50. The hot water supply system 1 may include a plurality of the remote controllers 50 installed at different places.
Instead of the remote controller 50 or in addition to the remote controller 50, it may be configured such that, a mobile terminal such as a smartphone or a tablet terminal, for example, can be used as the human interface of the hot water supply system 1. An example in which the remote controller 50 is used as a representative of the human interface will be mainly described below, whilst in the present disclosure, processes through use of the remote controller 50 can all be replaced by processes through use of the above-described mobile terminal.
Each of functions of the first controller 9 may be achieved by processing circuitry. The processing circuitry of the first controller 9 may include at least one processor 9a and at least one memory 9b. The at least one processor 9a may read out and execute a program saved in the at least one memory 9b, thereby achieving each of the functions of the first controller 9. The processing circuitry of the first controller 9 may include at least one piece of dedicated hardware.
Each of functions of the second controller 16 may be achieved by processing circuitry. The processing circuitry of the second controller 16 may include at least one processor 16a and at least one memory 16b. The at least one processor 16a may read out and execute a program saved in the at least one memory 16b, thereby achieving each of the functions of the second controller 16. The processing circuitry of the second controller 16 may include at least one piece of dedicated hardware.
The first controller 9 can exert control by means of inverter control, for example, such that the rotation speed of the compressor 4 is variable. The first controller 9 is equivalent to compressor control means for adjusting the rotation speed of the compressor 4.
The second controller 16 may be capable of exerting control by means of inverter control, for example, such that the rotation speed of the heat medium pump 13 is variable. The second controller 16 may be capable of exerting control by means of inverter control, for example, such that the rotation speed of the water pump 14 is variable.
The hot water supply system 1 can execute a hot water storage operation. The hot water storage operation is an operation for increasing the temperature of water in the hot water storage tank 11. The first controller 9 and the second controller 16 control the hot water storage operation. The first controller 9 and the second controller 16 control a behavior during the hot water storage operation as will be described below. The compressor 4, the heat medium pump 13, and the water pump 14 are driven. In the flow passage switching valve 15, the a port communicates with the c port, and the d port is closed. The refrigerant compressed by the compressor 4 to have high temperature and high pressure flows into the primary flow passage 5a of the heat medium heat exchanger 5. The refrigerant flowing through the primary flow passage 5a is cooled by the heat medium flowing through the secondary flow passage 5b. The refrigerant having passed through the primary flow passage 5a is decompressed by the expansion valve 6 to be low-temperature and low-pressure refrigerant. This low-temperature and low-pressure refrigerant flows into the evaporator 7. The evaporator 7 exchanges heat between the outside air guided by the blower 10 and the low-temperature and low-pressure refrigerant. The refrigerant is evaporated by being heated with the outside air in the evaporator 7. The evaporated refrigerant is sucked into the compressor 4. A refrigeration cycle is formed as described above.
The heat medium heated with the refrigerant in the heat medium heat exchanger 5 passes through the passage 28, the flow passage switching valve 15, and the passage 29 to flow into the primary flow passage 12a of the water heat exchanger 12. The heat medium having passed through the primary flow passage 12a passes through the passage 26, the branch part 25, the heat medium pump 13, and the passage 27 to return to the heat medium heat exchanger 5. A circuit in which the heat medium circulates passing through the heat medium heat exchanger 5 and the water heat exchanger 12 as described above will be hereinafter referred to as a “heat medium circuit”.
Water in the lower part of the hot water storage tank 11 passes through the outlet 17 and the water feed passage 19 to flow into the secondary flow passage 12b of the water heat exchanger 12. In the water heat exchanger 12, water flowing through the secondary flow passage 12b is heated with the heat medium flowing through the primary flow passage 12a. The heated water passes through the water return passage 20 and the inlet 18 to flow into an upper part of the hot water storage tank 11.
The second controller 16 makes the rotation speed of the water pump 14 relatively high such that the flow rate of water flowing in the water circuit 21 is relatively high. As a result, water is heated to a substantially uniform temperature in the hot water storage tank 11 with no temperature boundary layer formed over a range from the height of the inlet 18 to which the water return passage 20 is connected to the height of the outlet 17 to which the water feed passage 19 is connected. Hot water having passed through the water return passage 20 and the inlet 18 to flow into the hot water storage tank 11 rises to a position higher than the inlet 18 because of the buoyancy. As a result, the whole water in the hot water storage tank 11 is heated to a substantially uniform temperature. However, when hot water having a temperature higher than the temperature of water heated by the water heat exchanger 12 is left in the uppermost part 42 of the hot water storage tank 11, the high-temperature hot water may remain in the uppermost part 42.
The temperature of the heat medium flowing in the heat medium circuit increases continuously from the start of the hot water storage operation to completion of the hot water storage operation. The temperature of water flowing in the water circuit 21 increases continuously from the start of the hot water storage operation to completion of the hot water storage operation.
The first controller 9 may adjust an opening of the expansion valve 6 such that the compressor discharge temperature detected by the discharge temperature sensor 32 is equal to a predetermined temperature. As the opening of the expansion valve 6 is larger, the flow rate of the refrigerant increases, and the compressor discharge temperature decreases.
The second controller 16 may fix the rotation speed of the heat medium pump 13 at such a rotation speed that the flow rate of the heat medium flowing in the heat medium circuit is equal to a predetermined value. Alternatively, the second controller 16 may adjust the rotation speed of the heat medium pump 13 such that a difference between the heat pump exit temperature detected by the heat pump exit temperature sensor 38 and the heat pump entrance temperature detected by the heat pump entrance temperature sensor 37 is equal to a target temperature difference.
The second controller 16 may fix the rotation speed of the water pump 14 to such a rotation speed that the flow rate of water flowing in the water circuit 21 is equal to a predetermined value. Alternatively, the second controller 16 may adjust the rotation speed of the water pump 14 such that a difference between the tank flow-in temperature detected by the tank flow-in temperature sensor 40 and the tank flow-out temperature detected by the tank flow-out temperature sensor 39 is equal to the target temperature difference.
A plate-type heat exchanger, for example, may be used as the water heat exchanger 12. The plate-type heat exchanger has a structure that promotes heat transfer. Therefore, the use of the plate-type heat exchanger as the water heat exchanger 12 can reduce a difference between the temperature of the heat medium flowing through the primary flow passage 12a and the temperature of water flowing through the secondary flow passage 12b, enabling the hot water storage operation with higher efficiency to be carried out.
Next, the room-heating operation of the hot water supply system 1 will be described. The first controller 9 and the second controller 16 control the room-heating operation. The first controller 9 and the second controller 16 control a behavior during the room-heating operation as will be described below. The compressor 4 and the heat medium pump 13 are driven. The water pump 14 is stopped. In the flow passage switching valve 15, the a port communicates with the d port, and the c port is closed. A behavior of the heat pump apparatus 2 is the same as or similar to the behavior during the hot water storage operation. The heat medium heated with the refrigerant in heat medium heat exchanger 5 passes through the passage 28, the flow passage switching valve 15, and the passage 30 to flow into the room-heating apparatus 24. The room-heating apparatus 24 heats the room using heat of the heat medium. The temperature of the heat medium decreases during passage through the room-heating apparatus 24. The heat medium decreased in temperature passes through the passage 31, the branch part 25, the heat medium pump 13, and the passage 27 to return to the heat medium heat exchanger 5. A circuit in which the heat medium circulates passing through the heat medium heat exchanger 5 and the room-heating apparatus 24 as described above will be hereinafter referred to as a “room-heating circuit”.
In the present embodiment, the room-heating operation and the hot water storage operation can be switched by switching between the room-heating circuit and the heat medium circuit with the flow passage switching valve 15. The flow passage switching valve 15 is thus equivalent to a switching valve that switches between the room-heating operation and the hot water storage operation.
The tank unit 45 does not include the water heat exchanger 12, the water pump 14, the water circuit 21, the tank flow-out temperature sensor 39, and the tank flow-in temperature sensor 40. The tank unit 45 includes a water heat exchanger 46 arranged inside the hot water storage tank 11. A heat medium pipe 47 included in the water heat exchanger 46 has a shape wound into a helical shape or coil shape around a central axis of the hot water storage tank 11. The water heat exchanger 46 is immersed in the water in the hot water storage tank 11. As to a position in the vertical direction, the center of the water heat exchanger 46 is located at a position lower than the center of the hot water storage tank 11.
The water heat exchanger 46 has an entrance 48 and an exit 49. The entrance 48 is located at a position higher than the exit 49. An entrance passage 51 connects the c port of the flow passage switching valve 15 to the entrance 48 of the water heat exchanger 46. An exit passage 52 connects the exit 49 of the water heat exchanger 46 to the branch part 25.
In the illustrated example, the heat medium pipe 47 of the water heat exchanger 46 is arranged so as not to be in contact with an inner wall surface of the hot water storage tank 11. As a modification, the heat medium pipe 47 of the water heat exchanger 46 may be in contact with the inner wall surface of the hot water storage tank 11.
During the hot water storage operation through use of the tank unit 45, the heat medium heated by the heat medium heat exchanger 5 of the heat pump apparatus 2 passes through the passage 28, the flow passage switching valve 15, the entrance passage 51, and the entrance 48 to flow into the heat medium pipe 47 of the water heat exchanger 46. The heat medium having passed through the heat medium pipe 47 of the water heat exchanger 46 passes through the exit 49, the exit passage 52, the branch part 25, the heat medium pump 13, and the passage 27 to return to the heat medium heat exchanger 5. In the water heat exchanger 46, heat is exchanged between the heat medium flowing in the heat medium pipe 47 and the water in the hot water storage tank 11 which is in contact with an outer wall of the heat medium pipe 47, so that the water is heated. The water which is in contact with the outer wall of the heat medium pipe 47 rises because of the buoyancy when heated. As a result, a flow circulating because of natural convection is formed inside the hot water storage tank 11. Consequently, the whole water in the hot water storage tank 11 is heated to a substantially uniform temperature similarly to the case of the tank unit 3. However, when high-temperature hot water is left in the uppermost part 42 of the hot water storage tank 11, the high-temperature hot water may remain in the uppermost part 42.
In the following description, heat transfer performance of a water heat exchanger that exchanges heat between a heat medium and water stored in the hot water storage tank 11, such as the water heat exchanger 12 or the water heat exchanger 46, will be simply referred to as “heat transfer performance” in some cases.
The heat transfer performance of the water heat exchanger 46 of the tank unit 45 is lower than the heat transfer performance of the water heat exchanger 12 of the tank unit 3. A main factor thereof lies in that water in the water heat exchanger 12 creates forced convection, while water in the water heat exchanger 46 creates natural convection. In the present disclosure, the heat transfer performance can be expressed by an AK value, for example. The AK value is a value obtained by multiplying a heat transfer area A [m2] by an overall heat-transfer coefficient K [kW/(m2K)]. The heat transfer performance depends on the structure of the water heat exchanger.
The difference in heat transfer performance described above makes the efficiency of the hot water storage operation through use of the tank unit 45 lower than the efficiency of the hot water storage operation through use of the tank unit 3. On the other hand, the tank unit 45 has an advantage of being more inexpensive than the tank unit 3 because the water pump 14 and the water circuit 21 are not required.
A user of the hot water supply system 1 or a builder who constructs the hot water supply system 1 combines the tank unit 3 with the heat pump apparatus 2 in some cases from the viewpoint of giving weight to the efficiency of the hot water storage operation. On the other hand, the user or the builder combines the tank unit 45 with the heat pump apparatus 2 in some cases from the viewpoint of cutting down on installation cost. As described, the heat pump apparatus 2 is used in some cases in combination with the tank unit 3 including the water heat exchanger 12 having relatively high heat transfer performance or used in other cases in combination with the tank unit 45 including the water heat exchanger 46 having relatively low heat transfer performance.
When a stored hot water temperature detected by the stored hot water temperature sensor 35 reaches a target temperature, the hot water storage operation is terminated. A required time for the hot water storage operation is the time from the start of the hot water storage operation until the stored hot water temperature detected by the stored hot water temperature sensor 35 reaches the target temperature.
When it is assumed that the rotation speed of the compressor 4 during the hot water storage operation is the same, the required time for the hot water storage operation through use of the tank unit 45 having the water heat exchanger 46 having low heat transfer performance is longer than the required time for the hot water storage operation through use of the tank unit 3 having the water heat exchanger 12 having high heat transfer performance.
In order to prevent shortage of hot water in the hot water storage tank 11 while the room-heating operation is being carried out, the hot water supply system 1 suspends the room-heating operation to carry out the hot water storage operation and as soon as the hot water storage operation is terminated, resumes the room-heating operation in some cases. As the required time for the hot water storage operation is longer, the period in which the room-heating operation is suspended is longer. Since heat is not supplied to the room-heating apparatus 24 during suspension of the room-heating operation, the temperature of the room decreases. Therefore, prolongation of the required time for the hot water storage operation is not preferable.
The heat pump apparatus 2 of the present embodiment includes heat transfer performance determination means for determining the heat transfer performance. The heat transfer performance determination means in the present embodiment is implemented by the first controller 9. The heat transfer performance determination means may determine whether the heat transfer performance is higher or lower than a reference.
The first controller 9 adjusts the rotation speed of the compressor 4 during the hot water storage operation such that the rotation speed of the compressor 4 when the heat transfer performance determination means determines that the heat transfer performance is relatively low is higher than the rotation speed of the compressor 4 when the heat transfer performance determination means determines that the heat transfer performance is relatively high. This can avoid the required time for the hot water storage operation through use of the tank unit 45 having the water heat exchanger 46 having low heat transfer performance being longer than the required time for the hot water storage operation through use of the tank unit 3 having the water heat exchanger 12 having high heat transfer performance. Consequently, even when the tank unit 45 having the water heat exchanger 46 having low heat transfer performance is combined with the heat pump apparatus 2, prolongation of the period in which the room-heating operation is suspended can be avoided.
The rotation speed of the compressor 4 during the hot water storage operation may be kept constant or may vary. An average value of the rotation speed of the compressor 4 from the start to termination of the hot water storage operation will be referred to as an “average rotation speed of the compressor 4”. When the rotation speed of the compressor 4 varies during the hot water storage operation, the first controller 9 should only adjust the rotation speed of the compressor 4 during the hot water storage operation such that the average rotation speed of the compressor 4 when the heat transfer performance determination means determines that the heat transfer performance is relatively low is higher than the average rotation speed of the compressor 4 when the heat transfer performance determination means determines that the heat transfer performance is relatively high.
In the present embodiment, the heat transfer performance determination means of the first controller 9 measures the required time for the hot water storage operation when the hot water storage operation is executed and determines the heat transfer performance depending on the required time as measured. The heat transfer performance determination means can thus determine the heat transfer performance correctly and easily.
In the present embodiment, during an initial hot water storage operation after the hot water supply system 1 is installed, the heat transfer performance determination means of the first controller 9 measures the required time for the hot water storage operation and determines the heat transfer performance depending on the required time as measured. The hot water supply system 1 then carries out the second and subsequent hot water storage operations as ordinary hot water storage operations. During the ordinary hot water storage operations, the first controller 9 adjusts the rotation speed of the compressor 4 such that the rotation speed of the compressor 4 when the heat transfer performance determination means determines that the heat transfer performance is relatively low is higher than the rotation speed of the compressor 4 when the heat transfer performance determination means determines that the heat transfer performance is relatively high.
In step S202, the second controller 16 sets a target stored hot water temperature Thw. The target stored hot water temperature Thw may be a value set by the user using the remote controller 50.
In step S203, a water temperature Tcw of the hot water storage tank 11 before the start of the hot water storage operation is detected by the stored hot water temperature sensor 35. In the present embodiment, the water temperature Tcw of the hot water storage tank 11 before the start of the hot water storage operation is equivalent to a “first temperature”. The target stored hot water temperature Thw is equivalent to a “second temperature”.
In step S204, counting for measuring the required time for the hot water storage operation is started. In step S205, the hot water storage operation is carried out. In step S206, it is determined whether the stored hot water temperature detected by the stored hot water temperature sensor 35 has reached the target stored hot water temperature Thw. In a case where the stored hot water temperature detected by the stored hot water temperature sensor 35 has not reached the target stored hot water temperature Thw, the hot water storage operation is continued.
When the stored hot water temperature detected by the stored hot water temperature sensor 35 reaches the target stored hot water temperature Thw, the process transitions to step S207, where the hot water storage operation is terminated. In step S208, the counting for measuring the required time for the hot water storage operation is terminated. Subsequently, in step S209, a standard hot water storage operation time is calculated.
Herein, an example of a method for the first controller 9 to calculate the standard hot water storage operation time will be described using
In
The first controller 9 stores in advance the relationship between the stored hot water temperature and the heating capability as shown in
In the section 2, the amount of heating H2 [J] for the hot water storage tank 11, which is required for the stored hot water temperature to increase from Tt1-2 to Tt2-3, can be calculated by Expression (1) below from a water volume Mw [kg] in the hot water storage tank 11 and water specific heat Cpw [J/kgK].
Similar calculations can be made for the other sections. In addition, when the water temperature Tcw of the hot water storage tank 11 before the hot water storage operation is included in the section 1, the amount of heating H1 in the section 1 can be calculated by Expression (2) below.
In addition, when the target stored hot water temperature Thw is included in the section 4, an amount of heating H4 in the section 4 can be calculated by Expression (3) below.
As described above, the amount of heat required for heating the water in the hot water storage tank 11 from the water temperature Tcw to the target stored hot water temperature Thw is calculated in a manner separated for each section. When the required amount of heating as calculated is divided by the heating capability, a time required for heating the water in the hot water storage tank 11 from the water temperature Tcw to the target stored hot water temperature Thw can be calculated. Thus, a hot water storage operation time thu required for heating the water in the hot water storage tank 11 from the water temperature Tcw before the hot water storage operation to the target stored hot water temperature Thw can be calculated by Expression (4) below.
The above-described required hot water storage operation time thu is equivalent to the standard hot water storage operation time. Herein, the relationship between the stored hot water temperature and the heating capability shown in
When the standard hot water storage operation time thu is calculated as described above, the process transitions from step S209 to step S210 in
The hot water storage operation required time which is shorter than or equal to the standard hot water storage operation time thu is equivalent to relatively high heat transfer performance. When the hot water storage operation required time is shorter than or equal to the standard hot water storage operation time thu, the process transitions to step S212. In step S212, the first controller 9 maintains the rotation speed of the compressor 4 during the ordinary hot water storage operation to be carried out next or subsequently at the initial value set in step S201.
The processing of steps S211 and S212 is equivalent to adjustment of the rotation speed of the compressor 4 in the second or subsequent ordinary hot water storage operation such that the rotation speed of the compressor 4 when the heat transfer performance determination means determines that the heat transfer performance is relatively low is higher than the rotation speed of the compressor 4 when the heat transfer performance determination means determines that the heat transfer performance is relatively high.
Note that the first controller 9 may change the initial value of the rotation speed of the compressor 4 to be set in step S201 depending on the outside air temperature detected by the outside air temperature sensor 41.
The first controller 9 may change the rotation speed of the compressor 4 depending on the stored hot water temperature detected by the stored hot water temperature sensor 35 during the hot water storage operation. For example, the rotation speed of the compressor 4 may be increased continuously or stepwise as the stored hot water temperature increases. On that occasion, the first controller 9 should only adjust the rotation speed of the compressor 4 at each point of time during the hot water storage operation such that the rotation speed of the compressor 4 when the heat transfer performance is determined to be relatively low is higher than the rotation speed of the compressor 4 when the heat transfer performance is determined to be relatively high.
The first controller 9 may be configured to adjust the rotation speed of the compressor 4 during the hot water storage operation such that the difference between the heat pump exit temperature detected by the heat pump exit temperature sensor 38 and the stored hot water temperature detected by the stored hot water temperature sensor 35 is equal to the target temperature difference. As the target temperature difference is larger, the rotation speed of the compressor 4 is higher. Thus, the first controller 9 should only set the target temperature difference such that the target temperature difference when the heat transfer performance is determined to be relatively low is larger than the target temperature difference when the heat transfer performance is determined to be relatively high. As described above, the first controller 9 may not control the value itself of the rotation speed of the compressor 4. In other words, the rotation speed of the compressor 4 when the heat transfer performance is determined to be relatively low should only be resultantly higher than the rotation speed of the compressor 4 when the heat transfer performance is determined to be relatively high.
In order to make the required time for the hot water storage operation through use of the water heat exchanger 46 having low heat transfer performance equal to the required time for the hot water storage operation through use of the water heat exchanger 12 having high heat transfer performance, the difference between the heat pump exit temperature and the stored hot water temperature needs to be increased. According to the present embodiment, the rotation speed of the compressor 4 when the heat transfer performance is determined to be low is higher than the rotation speed of the compressor 4 when the heat transfer performance is determined to be relatively high during the second or subsequent ordinary hot water storage operation. Thus, the difference between the heat pump exit temperature and the stored hot water temperature increases. Consequently, even when the tank unit 45 having the water heat exchanger 46 having low heat transfer performance is connected to the heat pump apparatus 2, the required time for the hot water storage operation can be prevented from being prolonged. This can avoid prolongation of the period in which the room-heating operation is suspended.
According to the present embodiment, the rotation speed of the compressor 4 during the hot water storage operation can be adjusted automatically and appropriately depending on the heat transfer performance of the water heat exchanger of the tank unit connected to the heat pump apparatus 2. Consequently, the heat pump apparatus 2 is easily adaptable to a combination with a plurality of types of tank units different in heat transfer performance of the water heat exchanger. It is not necessary to subject the heat pump apparatus 2 to special adjustment depending on the type of the tank unit during installation.
A tank unit of a type in which water is circulated with the water pump 14 to the water circuit 21 which is a circulation circuit that connects the water heat exchanger 12 arranged outside the hot water storage tank 11 to the hot water storage tank 11 will be hereinafter referred to as an “external heat exchange type”. The tank unit 3 in
A tank unit of a type in which the heat medium pipe 47 included in the water heat exchanger 46 is arranged inside the hot water storage tank 11 will be hereinafter referred to as an “inner coil type”. The tank unit 45 in
Although illustration is omitted, there is also a tank unit of a type in which the heat medium pipe included in the water heat exchanger is in contact with the outer wall of the hot water storage tank 11. Such a tank unit will be hereinafter referred to as an “outer coil type”. In the tank unit of the outer coil type, the heat medium pipe included in the water heat exchanger is wound into a helical shape or coil shape around an outer periphery of the hot water storage tank 11. The wall of the hot water storage tank 11 is heated by heat of the heat medium flowing in the heat medium pipe which is in contact with the outer wall of the hot water storage tank 11. The water in the hot water storage tank 11 is heated by transfer of heat from an inner wall of the hot water storage tank 11 to water which is in contact with the inner wall. The water which is in contact with the inner wall of the hot water storage tank 11 is heated and rises, so that natural convection occurs. The heat pump apparatus 2 of the present embodiment can also be used while being connected to the tank unit of the outer coil type. The heat transfer performance determination means of the first controller 9 can also determine the heat transfer performance of the water heat exchanger of the tank unit of the outer coil type.
In the present embodiment, the initial value of the rotation speed of the compressor 4 in step S201 is set at a relatively low value, and when the heat transfer performance is determined to be low, the rotation speed of the compressor 4 shall be increased in step S211. Since the initial value of the rotation speed of the compressor 4 is set at a relatively low value as described above, the heat pump exit temperature can be prevented more reliably from becoming excessively high during the initial hot water storage operation. This can prevent more reliably control for protecting a product, such as a forced stop of the heat pump apparatus 2, from being actuated during the initial hot water storage operation.
Next, a second embodiment will be described with reference to
In the present embodiment, the heat transfer performance determination means of the heat pump apparatus 2 presents a plurality of options concerning the types of tank units on a human interface. A user of the hot water supply system 1 or a builder who constructs the hot water supply system 1 selects an option corresponding to a tank unit to be constructed from among the plurality of options as presented. The heat transfer performance determination means determines the heat transfer performance depending on the selected option. The human interface may be the remote controller 50 or may be a mobile terminal, for example. As described earlier, the heat transfer performance depends on the structure of the water heat exchanger. Therefore, by having the user or the builder select the type of the tank unit, the heat transfer performance determination means can determine the heat transfer performance without measuring the required time for the hot water storage operation.
The plurality of options presented by the heat transfer performance determination means include at least two options among an option indicating the tank unit of the external heat exchange type, an option indicating the tank unit of the inner coil type, and an option indicating the tank unit of the outer coil type. The external heat exchange type is equivalent to a first type. The inner coil type is equivalent to a second type. The outer coil type is equivalent to a third type.
As described earlier, the heat transfer performance of the water heat exchanger 46 of the inner coil type such as the tank unit 45 is lower than the heat transfer performance of the water heat exchanger 12 of the external heat exchange type such as the tank unit 3. In addition, the heat transfer performance of the water heat exchanger of the tank unit of the outer coil type is, because of its structure, usually lower than the heat transfer performance of the water heat exchanger of the tank unit of the inner coil type.
The heat transfer performance determination means of the heat pump apparatus 2 determines that the heat transfer performance of the external heat exchange type is the highest, determines that the heat transfer performance of the inner coil type is the second highest, and determines that the heat transfer performance of the outer coil type is the lowest. The heat transfer performance determination means can thus correctly determine the heat transfer performance depending on the type of the tank unit selected by the user or the builder.
The first controller 9 makes the rotation speed of the compressor 4 during the hot water storage operation when the option of the inner coil type is selected higher than the rotation speed of the compressor 4 during the hot water storage operation when the option of the external heat exchange type is selected. In addition, the first controller 9 makes the rotation speed of the compressor 4 during the hot water storage operation when the option of the outer coil type is selected higher than the rotation speed of the compressor 4 during the hot water storage operation when the option of the inner coil type is selected.
The heat transfer performance determination means of the heat pump apparatus 2 may cause the display 53 of the human interface to display icons corresponding to each of the plurality of options when presenting the plurality of options concerning the types of the tank units.
In the example shown in
In the example shown in
According to the present embodiment, by causing the display 53 to display the icon 54 and the icon 55 corresponding to each of the plurality of options concerning the types of the tank units, the user or the builder is able to readily understand an appropriate option corresponding to the type of the tank unit to be constructed.
The heat transfer performance determination means of the heat pump apparatus 2 may cause the display 53 to display names corresponding to each of the plurality of options when presenting the plurality of options concerning the types of the tank units, instead of causing the display 53 to display the icon 54 and the icon 55 corresponding to each of the plurality of options concerning the types of the tank units. Alternatively, both the icon 54 and the icon 55 as well as names corresponding to each of them may be displayed on the display 53.
When there is no history in which the hot water storage operation has been completed previously in step S301, it is considered that the present operation is the initial hot water storage operation, and the type of the tank unit has not been selected. In this case, the process transitions to step S302, where the hot water supply system 1 causes the display 53 to display the icon 54 and the icon 55 corresponding to each of the plurality of options concerning the types of the tank units.
The process transitions from step S302 to step S304, where the user or the builder selects an icon corresponding to the type of the tank unit to be constructed. When the icon 55 of inner coil type is selected, the heat transfer performance determination means determines that the heat transfer performance of the water heat exchanger is relatively low. In this case, the process transitions to step S305. In step S305, the first controller 9 sets the rotation speed of the compressor 4 during the hot water storage operation at a value obtained by adding a predetermined value to the initial value. The initial value is the same as the initial value set in step S201 in
When the icon 54 of the external heat exchange type is selected, the heat transfer performance determination means determines that the heat transfer performance of the water heat exchanger is relatively high. In this case, the process transitions to step S306. In step S306, the first controller 9 maintains the rotation speed of the compressor 4 during the hot water storage operation at the above-described initial value. Thereafter, the hot water supply system 1 carries out the hot water storage operation in accordance with the rotation speed of the compressor 4 maintained at the initial value.
The processing of steps S305 and S306 is equivalent to adjustment performed by the first controller 9 for the rotation speed of the compressor 4 during the hot water storage operation such that the rotation speed of the compressor 4 when the heat transfer performance determination means determines that the heat transfer performance is relatively low is higher than the rotation speed of the compressor 4 when the heat transfer performance determination means determines that the heat transfer performance is relatively high.
Note that the disclosure may be carried out combining two or more features that can be combined among the features included in the plurality of embodiments described above.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2021/048010 | 12/23/2021 | WO |
