JPH08296937A - Method for detecting cold insulation remaining time of cold storage type cold insulation box - Google Patents

Abstract

PURPOSE: To display cold insulation remaining time in cold storage type cooling. CONSTITUTION: A total heat of fusion of an eutectic liquid QS of a cold storage plate 2 in a thermally insulated cold insulation box 1 and an amount of heat QM transmitted from the inside of the cold insulation box 1 to the outside per unit time (t) at each of ambient temperatures RTM are calculated in advance, and cold insulation time (T) (QS/QM) at each temperature RT is obtained. RT0 at the time t0 of starting cold insulation is detected, cold insulation time To at the temperature is retrieved and then an amount of heat transmission Q1 at RT1 after an elapse of time (t) is subtracted from QS at t0 to obtain a remaining total heat of fusion QS1 ' at the time. A cold insulation remaining time TE1 at the time is calculated by multiplying the cold insulation time T1 by cold insulation remaining ratio P1 (QS1 '/QS). Q2 at the temperature RT2 after an elapse of time (t) is subtracted from QS1 ' to obtain a remaining total heat of fusion QS2 ' at the time and cold insulation remaining time TE2 is obtained by multiplying the cold insulation time T2 at RT2 by P2 (QS2 '/QS1 '). The same operations are repeated to detect and display cold insulation remaining time TE at every unit of time (t).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of detecting a cold storage time of a cold storage type cold storage box and a method of displaying a cold storage remaining time (a coolable time) by the detected value.

[0002]

[Technical background] With the improvement of eating habits, people are demanding more fresh foods, and various cold boxes (containers, etc.) are widely used in the transportation and delivery of various foods in order to cope with them. There is.

As a cooling means of this cold-insulating box, there is a cold-storage type, and as shown in FIG. 3, for example, a heat-insulating box (cooling box) 1 is mounted on a carrier, and the heat-insulating box 1 is provided in the heat-insulating box 1. A cool storage plate 2 is installed, and cool air a is sent out from the cool storage plate 2 to cool the inside of the heat insulating box 1. The cold storage plate 2 is a thin and flat container filled with the eutectic liquid, and this liquid is frozen while the vehicle is absent (mainly at night), and the heat of fusion of this liquid is used to produce cold air a.

[0004]

The cold storage cool box 1 is excellent in that it is easy to handle and inexpensive, but the cooling time is limited, that is, the cooling time is a cold storage plate. The biggest drawback is that the melting time of the eutectic liquid of 2 is limited. For this reason, the user must always pay attention to the remaining cold storage time (the time when cold storage is possible) before using.

However, the remaining cold storage time greatly changes due to changes in temperature depending on the four seasons, and changes greatly within a few days.
It is difficult for the user to deal with this change by experience. Therefore, the remaining cold storage time often elapses, and the freshness of the food in the cold storage box 1 may decrease. As a measure to prevent this, although the cold storage plate 2 still has a cold insulation power (although the eutectic liquid is not completely melted), the cold storage plate 2 is replaced early, but this early replacement is not possible. It is efficient and wasteful.

Under the above circumstances, it is an object of the present invention to objectively and easily know the remaining cold storage time.

[0007]

[Means for Solving the Problems] First, the cooling (refrigeration) by the regenerator (cooling plate 2) is performed by the latent heat Q of melting of the regenerator 2.
_It uses _S (kcal). Further, there is a heat transfer amount Q _M (kcal / h) due to heat leakage from the inside (inside the heat insulating box 1) to the outside due to the heat transmission coefficient K (kcal / m ² h ° C.). The mathematical expression of these relationships is as follows.

That is, assuming that the cold storage 2 is completely frozen and the temperature inside the refrigerator 1 is stable at a predetermined temperature T _K (° C.), the ambient temperature is RT (° C.), and the surface area of the container (insulation box 1) is A.
( _M ² ), the heat transfer amount Q _M (kcal / h) due to heat leakage from the inside to the outside is Q _M = K · A · (RT−T _K ), _{M, K = 0,1, 2 ...} (Same below) (Equation 2-1) Further, the total latent heat of fusion (total amount of heat of fusion) Q _S of the regenerator 2 heats from the inside to the outside while keeping the inside temperature constant, that is, the keeping time. Since it is the time consumed by the heat transfer amount Q _M due to the leakage of, the cooling time (cooling possible time) is T _M (h), then T _M = Q _S / Q _M (Equation 2-2) where: Cooling time T if ambient temperature RT is constant
_M can be calculated by Equation 2-2.

However, since the ambient temperature RT constantly fluctuates in the moving container 1, the higher the ambient temperature RT, the smaller the value of the cold insulation time T _M , and the lower the ambient temperature RT, the lower the ambient temperature RT becomes. Since a change such as an increase in the value of the cold insulation time T _M occurs, a new function with the ambient temperature RT as a variable will be examined.

Therefore, assuming that the ambient temperature RT _M is a function that changes with the unit time t, RT _M = f ₁ (t) (Equation 2-3) Therefore, the heat transfer amount Q _M (kcal / h) is Q to become _{M = K · a · (f} 1 (t) -T K) ( equation 2-4). If this is graphed, the curve shown in FIG. 1 is obtained.

In FIG. 1, when the heat transfer Q _M is increasing, the ambient temperature RT _M is increasing, and when it is decreasing, the ambient temperature RT _M is decreasing. is there. In addition, the cold insulation time (possible cold insulation time) T _M is the heat transfer amount Q at the ambient temperature RT _{M that} changes with time t.
_M is integrated at time t, and the value is the total latent heat of fusion Q of regenerator 2.
It can be said that it is the elapsed time until it becomes equal to _S.

However, the change in ambient temperature RT _M is
Whatever the user's usage, it is impossible to express this as a function of time. Therefore, in actual control, a method corresponding to the usage state of this user is required.

As the control method, in the cool box 1 to be kept cold, first, the heat transfer amount Q _M corresponding to each ambient temperature RT _M when the total latent heat of fusion Q _S of the cold storage plate 2 is made constant in advance. and basic data is calculated, and based on this data, the ambient temperature RT _M in cold remaining time T _E (h)
To calculate.

That is, as shown in FIG. 2, the ambient temperature RT _M is detected periodically, and it is assumed that the ambient temperature RT _M is constant in the range of the period (unit time t), and the cold start T ₀
Therefore, the ambient temperature RT _M is detected at each unit time t, the heat transfer amount Q _M at the ambient temperature R T _M is extracted from the basic data, and the heat transfer from the total latent heat of fusion (total heat of fusion) Q _{S is performed.} the amount Q _M subtracts one after the other, the residue melting the total amount of heat Q _S ', heat transfer amount Q _M of ambient temperature RT _M where the detected
Then, the divided value is divided by the remaining heat retention time T at the time of detection.
_EM .

In this way, the remaining cooling time T _EM is detected (calculated), and the value is displayed as it is, or it is displayed by a color-changing diode such as green → yellow → red. Shown to the person. At this time, appropriate correction based on a sudden temperature change or the like can be added. The unit time t is, for example, one hour to several hours, or tens of minutes such as 10 minutes or 20 minutes.

The structure of the above invention is the one according to claim 1, but as can be understood from FIG. 2, the present invention is a bar graph for grasping the cold insulation time T _M per unit time t, and is a curved line. Ambient temperature RT _M and cooling time T _M
There is an error between them (hatched part in the figure). For this reason, there is a problem in accuracy in this state. Therefore, the following configuration is adopted within a range that can be implemented as microcomputer software (claims 2 to 4).

First, in Table 1, the microcomputer table data (the above basic data) is examined. The heat transfer amount Q _M is regarded as a parameter only, and the relationship between the ambient temperature RT _M and the cold storage time T _M in Table 1 is calculated by the microcomputer. Remember. In addition, the concept of cold storage remaining ratio will be introduced. The coolness remaining amount ratio P is the ratio of the remaining cold storage amount to the total cold storage amount, and this ratio is (T _M-1 −t)
/ T _M-1 (claim 3) and corresponds to the slope of the relational curve in FIG.

[0018]

[Table 1]

Then, the remaining cooling time T _EM is first detected by
When the cold storage is completed, the ambient temperature RT ₀ is detected and
Based on the basic data of the cold storage time (the available cold storage time)
T ₀ is taken out, and the cold storage residual amount ratio at that time is P ₀ = 1. Then, the ambient temperature RT ₀ is kept constant until the next measurement cycle t, and when the coolness residual amount ratio P ₁ is calculated when the first measurement cycle t has elapsed, P ₁ = (T ₀ −t) / T ₀ (Equation 2-5) Further, when the cold insulation time T ₁ is extracted from the basic data of Table ₁ from the ambient temperature RT ₁ at this point and the cold insulation remaining time T _E1 is calculated, T _E1 = T ₁ · P ₁ (Equation 2 2-6).

Similarly, the residual cold storage ratio P ₂ at the time when the second measurement cycle t has elapsed is P ₂ = (T ₁ −t) / T ₁ (Equation 2-7), and at this time When the cold insulation time T ₂ is taken out from the ambient temperature RT ₂ and the cold insulation remaining time T _E2 is calculated, T _E2 = T ₂ · P ₂ (Equation 2-8).

Thereafter, the same processing is performed every measurement cycle t to calculate the remaining cold storage time T _EM . The control flow is shown in Table 2.
, And display this as appropriate.

[0022]

[Table 2]

The above cold remaining time detection method, the cold residual ratio P _M, pull the unit time t from the cold time T _M, although the value obtained by dividing the value in the cold time T _M, the heat transfer amount Q _S ′
When considering the amount of change in the cold residual ratio P _M, Q
And _{SM-1 '/ Q SM'} , its value is calculated in the same manner as 2-5～8 formula described above, the flow of the control is as shown in Table 3. This control is the invention according to claim 2, and P _M
= (Q _SM-1 ′ / Q _M-1 ) / (Q _SM ′ / Q _M ) = T _M-1 /
It may be T _M (claim 4).

[0024]

[Table 3]

[0025]

Since the present invention is constructed as described above,
The remaining cool time by the cold storage plate can be detected and displayed, and the handling and efficiency of the cold storage cold storage can be greatly improved.

[Brief description of drawings]

1] Relationship between cold storage time T _M and heat transfer amount Q _M

[Fig. 2] Relationship between ambient temperature RT _M and cooling time T _M

[Fig. 3] Examples of cold storage cool boxes

[Explanation of symbols]

1 Insulation box (cold box) 2. Cold storage plate (cool storage body) a Cold air T Cooling time (Coolable time) T _E Cooling remaining time t ₀ Cooling starting time t Unit time P Cooling residual amount ratio Q Heat transfer quantity Q _S Total melting heat quantity Q _S ′ Total remaining heat quantity RT ambient temperature

Claims (5)

[Claims] 1. An adiabatic cold insulation box 1 comprising a cold storage plate 2 filled with a eutectic liquid.
In the regenerator type cold storage box which is internally installed in the cold storage type cold storage box, wherein the heat of fusion of the eutectic liquid is used to cool the inside of the adiabatic cold storage box 1, in detecting the remaining cold storage time T _E (h), Total heat of fusion of eutectic liquid Q _S (kcal)
And the ambient temperature R of the heat insulation cool box 1
The heat transfer amount Q (kcal / h) from the inside of the adiabatic cool box 1 per unit time t at T (° C.) is calculated in advance, and each heat transfer amount Q is used as basic data. _{From 0} , the ambient temperature RT _M (M = 0, 1, 2, ...) Is detected for each unit time t, and the heat transfer amount Q _M at each ambient temperature RT _M is extracted from the basic data. From the above total heat quantity of fusion Q _S to its heat transfer quantity Q
_M is subtracted in sequence, and the total residual heat quantity Q _SM ′ is divided by the heat transfer quantity Q _M of the detected ambient temperature RT _M , and the divided value (Q _SM ′ / Q _M ), Remaining cold storage time T at the time of detection
_A method for detecting the remaining cold storage time of a cold storage cold storage box characterized by using _EM . 2. The method according to claim 1, wherein the cold storage remaining time of the cold storage cold storage box is detected, the ambient temperature R at the cold storage start time t _0.
The temperature T ₀ is detected, the total amount of heat Q _S of melting is divided by the amount of heat transfer Q ₀ at the ambient temperature RT ₀ to obtain the cold keeping time T _0, and then, after the elapse of a unit time t, the ambient temperature RT at that time
₁ of the heat transfer amount Q ₁ is subtracted from the melting total heat Q _S 'and, the residue melts the total amount of heat Q _S1' residual melting total heat Q _S1 at that time by the, divided by the heat transfer amount Q ₁ Te seek cold residual ratio P ₁ by dividing the melting total heat Q _S with obtaining the cold time T _1, is multiplied by the cold residual ratio P ₁ in the cold time T _1, the cold remaining time at that time T _E1 and after the unit time t has elapsed, the heat transfer amount Q ₂ at the ambient temperature RT ₂ at that time is subtracted from the total residual melting heat amount Q _S1 ′ to obtain the total residual melting heat amount Q _S2 ′ at that time, ', said melting total heat Q _S1 with obtaining the cold time T ₂ is divided by the heat transfer amount Q _2' the residue melting the total amount of heat Q _S2 obtains the cold residual ratio P ₂ is divided by the cold time T ₂ in the cold remaining ratio P ₂
The remaining cool time T _E2 at that time is multiplied by, and the same operation is repeated thereafter to detect the remaining cool time T _EM for each unit time t. Method. 3. The cold storage time detecting method for a cold storage cold storage box according to claim 2, wherein the cold storage residual amount ratio P _{M is set} to a cold storage time T.
The value obtained by subtracting the unit time t from the _M (T _M -t) the cold remaining time detection method of the cold storage type cold box, characterized in that a divided by the cold time T _M. 4. A cold time detection method of the cold storage type cold box according to claim 2, wherein the cold residual ratio P _M, the previous ambient temperature RT at cold temperature T _M of the ambient temperature RT _{M M-1} A method for detecting the remaining cold storage time of a cold storage cold storage box, which is a value (T _M-1 / T _M ) obtained by dividing the cold storage temperature T _M-1 in the above. 5. A method according to claim 1 to 4 cold remaining time display method of cold accumulation cool boxes and displaying the cold remaining time T _EM detected by cold remaining time detection method of the cold storage type cold box according to.