JPH0754238B2 - 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 using a temperature sensor provided in the heat storage tank. That is, the heat storage control is such that the set 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 set value, the heat storage is judged to be completed and heat storage in the heat storage tank is stopped.

SUMMARY OF 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
CH ₃ COO ・ 3H ₂ O) (melting point 58 ℃, melting heat 60kc
al / kg, specific heat of liquid phase 0.7kcal / kg ℃, specific heat of solid phase 0.4kcal / kg
℃), the temperature sensor set value is 65 ℃, and if the heat storage material can be used until the heat storage material reaches 20 ℃ at the start of heating, the heat storage amount at the completion of heat storage is 80.1 kcal / kg. After the heat is stored,
Since the amount of heat storage decreases due to heat leak from the heat storage tank, it is necessary to perform the heat storage operation again.

Therefore, set the temperature sensor setting value at the start of heat storage operation to 60 ℃.
Then, 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.

Further, if the set value of the temperature sensor is set to the temperature of the solid phase region of the heat storage material, the temperature cannot be detected until most of the heat storage amount is lost. Therefore, the temperature of the liquid phase must be set to the set value.

Therefore, when the temperature detected by the temperature sensor reaches 65 ° C and the heat storage operation is stopped, the temperature immediately reaches 60 ° C due to heat leakage due to the re-evaporation of the refrigerant and the temperature difference from the ambient temperature, and the heat storage operation is restarted. By the way, even though the heating operation was stopped, it was repeatedly operated and stopped frequently, resulting in a decrease in efficiency. In addition, the user is uncomfortable.

Even when the heat storage is used during the defrosting operation, the efficiency similarly decreases during the heating operation, and the refrigerant noise generated by switching the valve causes the user to feel uncomfortable.

In view of the above problems, the present invention detects the temperature of the heat storage tank and the ambient temperature of the heat storage tank, and controls the heat storage amount of the heat storage tank using this temperature, without causing discomfort to the user, and also in efficiency. The purpose is to control the amount of heat storage well.

Means for Solving the Problems In order to solve the above problems, the heat storage control method of the present invention uses heat storage means for storing heat in a heat storage material filled with a latent heat storage material inside, and heat stored in the heat storage tank. The heat storage utilization means and the temperature detection means for detecting the temperature of the heat storage tank and the ambient temperature of the heat storage tank are provided, and the temperature of the heat storage tank detected by the temperature detection means is a predetermined value in the temperature range of the liquid phase of the latent heat storage material. When it is equal to or more than a value, the heat storage is stopped, and the relationship between the temperature difference between the heat storage tank and the surroundings of the heat storage tank and the amount of heat radiation from the heat storage tank to the surroundings is determined. The two temperatures are measured to integrate the heat radiation amount, and when the integrated value becomes equal to or more than a predetermined value, the heat storage tank is made to store heat again.

Further, the relationship between the temperature difference between the heat storage tank and the surroundings of the heat storage tank and the stop time of heat storage in the heat storage tank by the heat storage means is determined, and when the heat storage by the heat storage means is stopped, the two temperature detection means are provided by the temperature detection means at a predetermined cycle. The temperature is measured, the stop time is calculated, and when the time from the start of measurement to the time of measurement becomes the stop time or longer, the heat storage means again stores heat in the heat storage tank. By adopting the means, the heat storage amount of the heat storage tank can be efficiently controlled without giving a discomfort to the user.

In addition, the relationship between the temperature difference between the heat storage tank and the surroundings of the heat storage tank and the amount of heat radiation, or the relationship between the temperature difference between the heat storage tank and the surroundings of the heat storage tank and the stop time is defined, and the relationship is used to perform control more reliably. It is possible to control the amount of heat stored.

Embodiment Hereinafter, the present invention will be described with reference to FIGS. 1 to 5 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. A heat storage tank 6 is provided with a heat storage exchanger 7 and a heat absorption exchanger 8 therein, and is filled with a latent heat storage material 9 for storing heat by utilizing 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, Heat exchanger 8 for heat absorption in the middle of the path
Is a second bypass circuit having a. Also, 12 to 17 two-way valves are provided to switch the refrigerant flow paths. Furthermore, a third bypass having a two-way valve 18 provided on the way is connected to a pipe line between the two-way valve 17 and the outdoor heat exchanger 5 and a pipe line between the heat-absorption heat exchanger 8 and the two-way valve 16. A circuit 19 is provided. Reference numerals 20 and 21 denote temperature sensors mounted inside the heat storage tank 6 and around the heat storage tank 6, respectively. The temperature detection circuit 22 detects each temperature and sends a signal to the microcomputer 23. The microcomputer 23 performs calculation to control the relay 24.
Send a signal to. The control relay 24 is a microcomputer
Upon receiving a signal from 23, the compressor 1, the two-way valves 12 to 18, and the indoor / outdoor fans (not shown) are controlled.

In FIG. 2, ◯ indicates the valve is open, and x indicates the valve is closed.

In this heat pump type air conditioner, each operation mode shown in FIG. 2 will be explained. 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 includes the four-way valve 2, the indoor heat exchanger 3, the expansion valve 4, the outdoor heat exchanger 5,
It flows in the order of the four-way valve 2 and is sucked into the compressor 1. At this time,
No heat is stored in the heat storage tank 6.

To store heat in the heating mode, the two-way valve 12 is closed and the two-way valves 13 and 14 are opened.

Therefore, the refrigerant discharged from the compressor 1 flows in the order of 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. Inhaled into. At this time, a part of the heat of the high-temperature, high-pressure refrigerant sucked out 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. Used for heating in 3.

Next, even when the heating summer operation is stopped, if the heat storage tank 6 has a heat storage amount of a predetermined amount or more, this heat can be used at the next heating start-up.

In the start-up mode using heat storage, the two-way valve 12,15,
16 is open and the others are closed. At this time, 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 second bypass circuit 11, and the four-way valve 2, and is 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 flows into the four-way valve 2, the indoor heat exchanger 3, the expansion valve 4, and the second bypass circuit 11 and, after passing through the heat absorbing heat exchanger 8,
The third 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 storage tank 6
Defrosting is performed while continuing heating using the heat stored in.

Furthermore, in order to perform the start-up mode using heat storage, it is necessary to maintain the heat storage amount of a predetermined amount or more even when the heating operation is stopped. Therefore, when the heat storage amount decreases due to heat leakage, it is necessary to operate the heat storage mode. . 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 FIGS.

FIG. 3 is a flow chart of heat storage amount control during heating stop, FIG. 4 is a diagram showing the relationship between the temperature difference between the inside of the heat storage tank and the surroundings and the amount of heat radiation, and FIG. 5 is between the inside of the heat storage tank and the surroundings. It is a figure which shows the relationship between a temperature difference and the stop time of heat storage mode operation.

In FIG. 3, T ₁ and T ₂ are temperature detection circuits 22 respectively.
The temperature at the mounting position of the temperature sensors 20 and 21 detected in step Tc is the liquid phase region of the latent heat storage material 9, which is the heat storage completion temperature. Further, q is the heat radiation amount (heat leak amount) from the heat storage tank 6 per unit time, Δτ is the measurement cycle of T ₁ and T ₂ , Q is the integrated heat radiation amount from the heat storage tank 6, and Qc is the allowable heat radiation amount. .

First, the microcomputer 23 reads the operation status for a predetermined period, and when it confirms that the heating operation has stopped, it reads T ₁
In the following cases, the heat storage mode operation is performed and heat is stored in the heat storage tank 6. When T ₁ > Tc, it is determined that the heat storage is completed, and the heat storage mode operation is stopped.

The heat radiation amount q from the heat storage tank 6 per unit time is q = KA
It can be represented by (T1-T2) (where K is the heat transmission rate and A is the heat transfer area). Since K and A are constants, q is a linear function of (T1-T2) as shown in FIG.

Therefore, if this function is determined beforehand by experiments or the like, q can be known if T1 and T2 are known. Next, T1 and T2 are read, q is calculated from the relationship shown in FIG. 4, and Q is calculated. That is, Q = Δτq ₁ + Δτq ₂ + ... + Δτq _n = ΔτΣq This is repeated until Q> Qc, and when Q> Qc, T ₁ > Tc again in heat storage mode operation And repeat the flow again.

As described above, the heat storage amount control is performed not only by detecting only the temperature of the heat storage tank as in the conventional case but also by detecting the ambient temperature and calculating the heat radiation amount, so that the operation and the stop can be repeated frequently. Absent. Therefore, the heat storage amount can be efficiently controlled without giving discomfort to the user.

Also, the heat storage amount control can be performed by using the relationship shown in FIG. That is, the relationship between (T ₁ −T ₂ ) and the stop time of the heat storage mode operation (time until the heat storage amount falls below the allowable value) is determined as shown in FIG. 5, and the heating operation is stopped at predetermined intervals. Then, T ₁ and T ₂ are detected, and the stop time when T ₁ and T ₂ are detected is calculated from the relationship shown in FIG. If the time from the heating operation stop to the detection time is longer than the calculated stop time,
It is determined that the heat storage amount has become less than the allowable value, the heat storage mode operation is performed until T ₁ > Tc, and the above flow is repeated again. In this heat storage amount control, if the change in T ₂ during the heating operation is large, the detection accuracy becomes worse than the control shown in FIG. 3, but there is no need to perform integration in the calculation process, and the capacity of the microcomputer is small. Good.

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. Also,
Regarding the temperature around the heat storage tank, the heat pump type air conditioner described in the present embodiment may detect the outside air temperature when the heat storage tank is housed inside the outdoor unit.

Further, in order to perform defrosting using heat storage, the heat storage amount control is performed in the heating mode, and the heat storage amount control of the present invention is also effective at this time.

Further, in the present embodiment, an example in which the present invention is applied to a heat pump type air conditioner has been described, but the present invention is not limited thereto, and a latent heat storage material is filled in a heat storage tank such as a water heater using heat storage. Can also be used for 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.

Effects of the Invention As described above, the heat storage control method of the present invention detects the temperature of the heat storage tank and the ambient temperature of the heat storage tank, and controls the heat storage stop time using the detected temperature to control the heat storage amount. Therefore, the heat storage amount can be efficiently controlled without giving a discomfort to the user.

[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 an explanatory diagram showing operating states of valves of the heat pump type air conditioner, and FIG. 3 is a state in which the heating is stopped. FIG. 4 is a flow chart of the heat storage amount control, FIG. 4 is a characteristic diagram showing the relationship between the temperature difference between the inside of the heat storage tank and the surroundings and the heat radiation amount, and FIG. 5 is the temperature difference between the inside of the heat storage tank and the surroundings and the heat storage mode It is a characteristic view which shows the relationship with the stop time of driving. 6 ... Heat storage tank, 7 ... Heat storage heat exchanger, 8 ... Endothermic heat exchanger, 9 ... Latent heat storage material, 20, 21 ... Temperature sensor, 22
...... Temperature detection circuit, 23 ...... Microcomputer, 24 ...
… Control relays.

Claims (2)

[Claims] 1. A heat storage means for storing heat in a heat storage material filled with a latent heat storage material, a heat storage utilizing means for utilizing heat stored in the heat storage tank, and a temperature of the heat storage tank and an ambient temperature of the heat storage tank. When the temperature of the heat storage tank detected by the temperature detection means is equal to or higher than a predetermined value in the temperature range of the liquid phase of the latent heat storage material, the heat storage is stopped and the heat storage tank and the heat storage means are provided. The relationship between the temperature difference between the tank and the surroundings and the amount of heat radiation from the heat storage tank to the surroundings is determined, and when the heat storage is stopped, the temperature detecting means measures the two temperatures at a predetermined cycle and integrates the amount of heat radiation, A heat storage control method in which the heat storage tank stores heat again when the integrated value becomes equal to or larger than a predetermined value. 2. A heat storage means for storing heat in a heat storage material filled with a latent heat storage material, a heat storage utilizing means for utilizing heat stored in the heat storage tank, a temperature of the heat storage tank and an ambient temperature of the heat storage tank. When the temperature of the heat storage tank detected by the temperature detection means is equal to or higher than a predetermined value in the temperature range of the liquid phase of the latent heat storage material, the heat storage is stopped and the heat storage tank and the heat storage means are provided. Define the relationship between the temperature difference between the tank surroundings and the stop time of heat storage in the heat storage tank by the heat storage means,
When the heat storage by the heat storage means is stopped, the two temperatures are measured by the temperature detection means in a predetermined cycle to calculate the stop time, and when the time from the start of measurement to the measurement time is equal to or longer than the stop time, the temperature is again measured. A heat storage control method in which heat is stored in the heat storage tank by heat storage means.