JPH06100359B2 - Heat storage control method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a heat storage control method for a heat pump type air conditioner or the like that uses heat storage.

Conventional technology Conventionally, as an example of using heat storage in a refrigeration cycle, in a heat pump type air conditioner, a part of the heat of the gas discharged from the compressor is stored in a heat storage tank, and is used during a heating start-up operation or a defrosting operation. There is one that utilizes the accumulated heat (for example, JP-A-62-178855). In this heat pump type air conditioner, the amount of heat stored in the heat storage tank (heat storage device) is controlled by
This was done using a temperature sensor provided in the heat storage tank. That is, the installed value of the temperature sensor is set to a predetermined value in the temperature range of the liquid phase of the heat storage material, and when the detected temperature is equal to or higher than the installed value, it is determined that the heat storage is completed and heat storage is stopped in the heat storage tank. .

Problems to be Solved by the Invention However, the above conventional heat storage control method has the following problems.

That is, in order to use the heat storage for the heating start-up operation, the heat storage in the heat storage tank must be completed before the operation starts, so even if the temperature sensor provided in the heat storage tank falls below the predetermined value even when the heating operation is stopped You need to drive.
Here, for example, sodium acetate trihydrate (Na
CHCOO.3H ₂ O) (melting point 58 ℃, heat of fusion 60kcal)
/ kg, specific heat of liquid phase 0.7kcal / kg ° c, specific heat of solid phase 0.4kcal / kg °
c) If the set value of the temperature sensor is 65 ° C. and the heat storage material can be used until the temperature of the heat storage material reaches 20 ° C. at the start of heating, the heat storage amount at the completion of heat storage is 801 kcal / kg. After the heat storage is completed, the heat storage amount is reduced due to the heat leak from the heat storage tank, and therefore the heat storage operation needs to be performed again. Therefore, if the set value of the temperature sensor at the start of the heat storage operation is set to 60 ° C, after the heat storage is completed, the heat storage operation must be performed again with a heat leak of only 2.5% of the heat storage amount. If the set value of the temperature sensor is set to the temperature of the solid phase region of the heat storage material, detection cannot be performed until most of the stored heat amount is lost. Therefore, the temperature of the liquid phase must be set to the set value. For this reason, if the temperature detected by the temperature sensor reaches 65 ° C and the heat storage operation is stopped, the heat will leak immediately due to re-evaporation of the refrigerant and a heat leak due to the temperature difference from the ambient temperature.
When the temperature reached 60 ° C, the heat storage operation was restarted, and the operation was frequently repeated even while the heating operation was stopped, resulting in a drop in efficiency. In addition, the user is uncomfortable. Similarly, in the case of using heat storage during the defrosting operation, the efficiency during the heating operation is reduced, and the refrigerant noise generated by switching the valve causes the user to feel uncomfortable.

In view of the above-mentioned problems, the present invention determines the heat storage stop time as a function of the immediately preceding heat storage time in the heat storage mode in which the heat storage tank holds a heat storage amount equal to or more than a predetermined value, without causing discomfort to the user, and The purpose is to efficiently control the amount of heat storage.

Means for Solving the Problems In order to solve the above problems, the heat storage control method of the present invention uses a heat storage means for storing heat in a heat storage tank filled with a latent heat storage material and a heat storage using the heat stored in the heat storage tank. In a heat storage mode in which a utilization means is provided and a temperature detection means for detecting the temperature of the heat storage tank is provided, and heat storage in the heat storage tank using the heat storage means and heat storage stop are repeated to hold a heat storage amount of a predetermined value or more. When the temperature of the heat storage tank detected by the temperature detecting means becomes a predetermined value or more in the temperature range of the liquid phase of the latent heat storage material, the heat storage in the heat storage tank is stopped, and the heat storage stop time is set immediately before the heat storage. It is defined as a function of time.

Effect The present invention, by adopting the above means, can perform the heat storage amount control of the heat storage tank efficiently with a simple configuration without causing the user discomfort.

Embodiment Hereinafter, the present invention will be described with reference to FIGS. 1 to 4 of the accompanying drawings showing an embodiment thereof.

FIG. 1 is a refrigeration cycle diagram of a heat pump type air conditioner in one embodiment of the present invention, and FIG. 2 is a diagram showing operating states of valves during each operation of the heat pump type air conditioner.

In FIG. 1, the main refrigerant circuit is configured by connecting a compressor 1, a four-way valve 2, an indoor heat exchanger 3, an expansion valve 4, and an outdoor heat exchanger 5 in an annular shape. Reference numeral 6 denotes a heat storage tank, in which a heat storage heat exchanger 7 and an endothermic heat exchanger 8 are arranged and filled with a latent heat storage material 9 which stores heat by utilizing a phase change. Reference numeral 10 is a first bypass circuit that bypasses the pipeline connecting the compressor 1 and the four-way valve 2, and has a heat storage heat exchanger 7 in the middle of the pipeline, and 11 bypasses the outdoor heat exchanger 5, It is a second bypass circuit having a heat absorbing heat exchanger 8 in the middle of the path. Also, 12 to 17 two-way valves are provided to switch the refrigerant flow paths. Further, a pipe line between the two-way valve 17 and the outdoor heat exchanger 5 and a pipe line between the heat absorbing heat exchanger 8 and the two-way valve 16 are connected, and a two-way valve 18
The third bypass circuit 19 provided with is disposed. Reference numeral 20 denotes a temperature sensor mounted inside the heat storage tank 6, and the temperature detection circuit 21 detects this temperature and sends a signal to the microcomputer 22. The microcomputer 22 performs a calculation and sends a signal to the control relay 23. The control relay 23 receives a signal from the microcomputer 22 and receives the signal from the compressor 1 or the two-way valve.
12-18, control indoor and outdoor fans (not shown).

In FIG. 2, the open circles indicate the valve open, and the crosses indicate the closed state.

In this heat pump type air conditioner, each operation mode shown in FIG. 2 will be described. First, in the cooling mode, the two-way valves 12 and 17 are open, and the refrigerant discharged from the compressor 1 is the four-way valve 2. The outdoor heat exchanger 5, the expansion valve 4, the indoor heat exchanger 3, and the four-way valve 2 flow in this order, and are sucked into the compressor 1.

In heating mode, when not storing heat, two-way valve
The state of 12 to 18 is the same as in the cooling mode, and only the four-way valve 2 is switched to the heating cycle side. Therefore, the refrigerant discharged from the compressor 1 flows in the order of the four-way valve 2, the indoor heat exchanger 3, the expansion valve 4, the outdoor heat exchanger 5, and the four-way valve 2, and the compressor 1
Inhaled into. At this time, heat is not stored in the heat storage tank 6.

In the heating mode, when heat is stored, the two-way valve 12 is closed and the two-way valves 13 and 14 are opened. Therefore, the compressor 1
The refrigerant discharged from the first bypass circuit 10, the four-way valve 2,
The indoor heat exchanger 3, the expansion valve 4, the outdoor heat exchanger 5, and the four-way valve 2 flow in this order and are sucked into the compressor 1. At this time, a part of the heat of the high-temperature, high-pressure refrigerant discharged from the compressor 1 is given to the latent heat storage material 9 from the heat storage heat exchanger 7 to be stored therein, and the remaining heat is stored in the indoor heat exchanger 3 Used for heating.

Next, even when the heating operation is stopped, if the heat storage tank 6 has a heat storage amount of a predetermined amount or more, it is possible to use this heat at the next heating start-up. In the rising mode using heat storage, the two-way valves 12, 15, 16 are open and the others are closed. At this time, the refrigerant discharged from the compressor 1 is the four-way valve 2,
The indoor heat exchanger 3, the expansion valve 4, the second bypass circuit 11, and the four-way valve 2 flow in this order and are sucked into the compressor 1. Therefore, the high-temperature and high-pressure refrigerant discharged from the compressor 1 is used for heating in the indoor heat exchanger 3, reduced in pressure by the expansion valve 4 to low temperature and low pressure, and flows into the second bypass circuit 11 to absorb heat. The heat stored in the heat storage tank 6 is absorbed from the heat exchanger 8 for use, and is sucked into the compressor 1 via the four-way valve 2.

Further, when the heat storage tank 6 has a heat storage amount of a predetermined amount or more in the heating mode, it is possible to use the heat storage during defrosting. In the defrosting mode, the two-way valves 12, 15, 18 are open and the others are closed. At this time, the refrigerant discharged from the compressor 1 is
After flowing through the four-way valve 2, the indoor heat exchanger 3, the expansion valve 4, and the second bypass circuit 11, passing through the heat absorbing heat exchanger 8, the third
The bypass circuit 19, the outdoor heat exchanger 5, and the four-way valve 2 flow in this order and are sucked into the compressor 1. Therefore, the heat stored in the heat storage tank 6 is used to defrost while continuing heating.

Furthermore, in order to perform the start-up mode using heat storage, it is necessary to maintain a predetermined amount or more of heat storage even when the heating operation is stopped. Therefore, when the heat storage amount decreases due to heat leak, it is necessary to operate the heat storage mode. There is. In the heat storage mode, the flow of the refrigerant is the same as when the heat is stored in the heating mode, but since the heating is not performed, the indoor fan is stopped.

Next, regarding the heat storage amount control during the above-described heating operation stop,
A description will be given with reference to the drawings and FIG. FIG. 3 is a flowchart of heat storage amount control during heating stop, and FIG. 4 is a view showing a relationship between heat storage operation time and stop time.

In FIG. 3, first, the microcomputer 22 reads the operation status at a predetermined cycle, and when it confirms that the heating operation has stopped, it resets the timer and starts counting. Then, the process waits until the time τ ₁ after the timer starts counting becomes equal to or longer than the stop time τ _s obtained from the relational expression described later. Since this τ _s cannot be obtained at the first stop after the heating operation is finished, an initial value is set and used. And τ ₁ ≧ τ _s
Then, the timer is reset (counting is performed) and the heat storage operation is started. During the heat storage operation, the temperature T _{1 at} the mounting position of the temperature sensor 20 detected by the temperature detection circuit 21 at a predetermined cycle
Is read, and T ₁ is compared with the heat storage completion temperature T _s set in the liquid phase region of the latent heat storage material 9, and when T ₁ ≧ T _s , the heat storage operation is stopped. Then, τ _s is calculated from the heat storage operation time τ _t from the start of the heat storage operation to the stop. The relationship between τ _t and τ _s is the fourth
As shown in the figure. That is, the longer the heat storage operation time τ _t , the greater the amount of heat released to the surroundings of the heat storage tank 6 at the time of the stop immediately before that, so it is necessary to shorten the next stop time τ _s . Approximately, τ _s = A + (B / τ _t ) can be expressed (A and B are constants). Using this relational expression, τ _s is calculated from τ _t , the timer is reset again, and counting is started. Then, the heat storage operation is stopped until τ ₁ ≧ τ _s using the value obtained from the above relational expression as τ _s . Thereafter, this flow is repeated to hold the heat storage amount equal to or more than the predetermined value.

As described above, the heat storage amount control is not performed only by detecting the temperature of the heat storage tank as in the conventional case, but the heat storage operation stop time τ _s is set as a function of the heat storage operation time τ _t immediately before the heat storage operation stop time τ _s , so that the operation is frequently performed. , Stop is not repeated. Therefore, the heat storage amount can be efficiently controlled without giving discomfort to the user.

In this embodiment, the relationship between the heat storage operation time τ _t and the heat storage operation stop time τ _s is shown by a simple formula, but the present invention is not limited to this and other relational expressions may be used.

Although the temperature inside the heat storage tank is detected in the present embodiment, the temperature at another position such as the outer surface of the heat storage tank may be detected if the temperature of the latent heat storage material can be detected approximately.

Further, in the present embodiment, an example of applying the present invention to a heat pump type air conditioner has been described, but the present invention is not limited to this, such as a water heater using heat storage, such as a latent heat storage material filled in a heat storage tank. It is also applicable to other devices having a heat storage means for storing heat in the heat storage tank and a heat storage utilizing means for utilizing the stored heat.

As described above, the heat storage control method of the present invention, in the heat storage mode in which the heat storage tank holds a heat storage amount of a predetermined value or more, by determining the heat storage stop time as a function of the heat storage time immediately before it, the user can The heat storage amount can be efficiently controlled without giving discomfort.

[Brief description of drawings]

FIG. 1 is a refrigeration cycle diagram of a heat pump type air conditioner in one embodiment of the present invention, FIG. 2 is a diagram showing operating states of valves of the heat pump type air conditioner, and FIG. 3 is heat storage while heating is stopped. FIG. 4 is a flow chart of the quantity control, and FIG. 4 is a diagram showing the relationship between the heat storage operation time and the stop time. 6 ... Heat storage tank, 7 ... Heat storage heat exchanger, 8 ... Endothermic heat exchanger, 9 ... Latent heat storage material, 20 ... Temperature sensor, 21 ...
Temperature detection circuit, 22 …… Microcomputer, 23 …… Control relay.

Claims (1)

[Claims] 1. A temperature detecting means for detecting the temperature of the heat storage tank, comprising heat storage means for storing heat in a heat storage tank filled with a latent heat storage material and heat storage utilizing means for using the heat stored in the heat storage tank. In the heat storage mode in which the heat storage means retains a heat storage amount of a predetermined value or more by repeating heat storage and heat storage stop in the heat storage tank by using the heat storage means, the temperature of the heat storage tank detected by the temperature detection means is the latent heat. A heat storage control method in which the heat storage in the heat storage tank is stopped when the temperature exceeds a predetermined value in the temperature range of the liquid phase of the heat storage material, and the heat storage stop time is determined as a function of the heat storage time immediately before.