Temperature control system and temperature control method

Abstract

To inhibit a decline in temperature control effectiveness of the gas as it approaches the tip side of a blowout duct.SOLUTION: A temperature control system 1 includes: a blowout duct 3 having a plurality of blowout holes 4 along a longitudinal direction; and a gas supplier 2 that delivers a gas G from a proximal end of the blowout duct 3 into an interior of the blowout duct 3. When K is a value expressed by the following formula [1 / s] and L0 is a duct length [m] of the blowout duct 3, an inflow velocity of the gas G at the proximal end 3a of the blowout duct 3 is more than one time of K×L0 [m / s].SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a temperature adjustment system and a temperature adjustment method. [Background technology]

[0002] Patent Document 1 discloses an air conditioning system that includes a long cultivation bed in which strawberries and other cultivated crops are planted, an air conditioner arranged at the base end of the cultivation bed, and an outlet duct arranged to extend from the air conditioner along the cultivation bed, in which cool and warm air from the air conditioner is compressed and sent to the outlet duct, and supplied from the outlet duct to the cultivated crops.

[0003] In this air conditioning system, the air duct has multiple air outlets along the longitudinal direction, and the opening area of ​​the air outlets per unit length of the duct is set based on the static pressure and pressure loss in the air duct so that the air volume of the air duct has peaks where it changes from an increasing trend to a decreasing trend at multiple positions between the base end and the tip end of the air duct, thereby preventing large variations in the air volume of the air duct along the longitudinal direction. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6800728 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in conventional temperature adjustment systems, the temperature difference between the temperature of the gas flowing inside the blow-out duct (the internal temperature of the blow-out duct) and the external temperature of the blow-out duct is not taken into consideration.

[0006] In other words, when the temperature outside the blow-out duct is low and heating is performed with a temperature control system, heat is dissipated from the inside of the blow-out duct to the outside, and the gas flowing inside the blow-out duct tends to be cooled as it approaches the tip of the blow-out duct. On the other hand, when the temperature outside the blow-out duct is high and cooling is performed with a temperature control system, heat is dissipated from the outside to the inside of the blow-out duct, and the gas flowing inside the blow-out duct tends to be warmed as it approaches the tip of the blow-out duct. As a result, the temperature difference between the inside and outside of the blow-out duct becomes smaller as it approaches the tip of the blow-out duct.

[0007] Therefore, even if the variation in the blown air volume in the longitudinal direction of the blown duct is suppressed, the temperature control effect (cooling effect or heating effect) of the gas may be significantly reduced at the tip side of the blown duct.

[0008] An object of the present invention is to suppress a decrease in the temperature regulating effect of gas as the distance approaches the tip end side of the blow-out duct. [Means for solving the problem]

[0009] (1) The present invention, which has been invented to solve the above problems, is a temperature control system comprising an air outlet duct having a plurality of outlet holes along the longitudinal direction, and a gas supplier that supplies gas from the base end side of the air outlet duct into the inside of the air outlet duct, in which the gas is circulated inside the air outlet duct and supplied to the outside of the air outlet duct from the outlet holes, wherein K is a value [1 / s] expressed by the following formula, and L0 is the duct length [m] of the air outlet duct, and the inflow velocity of the gas at the base end of the air outlet duct is adjusted to m times K×L0 [m / s] (where m>1).

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[0010] In this way, by making the inflow velocity of the gas at the base end of the blow-out duct more than 1 time K×L0 [m / s], it is possible to suppress the decrease in the temperature difference between the inside and outside of the blow-out duct as it approaches the tip of the blow-out duct, and as a result, it is possible to suppress the decrease in the temperature control effect of the gas as it approaches the tip of the blow-out duct.

[0011] (2) In the above configuration (1), it is preferable that the inflow velocity of the gas at the base end of the blow-off duct is adjusted to be 1.5 to 24 times K×L0 [m / s].

[0012] In this way, the inflow velocity of the gas at the base end of the blow-out duct can be kept to a minimum while suppressing the deterioration of the temperature control effect due to the gas in the longitudinal direction of the blow-out duct, thereby saving the supply energy (power consumption) and supply amount of the gas.

[0013] (3) In the above configuration (1) or (2), it is preferable that the distribution of the area per unit length of the blowing holes satisfies the following formula:

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[0014] In other words, based on this formula, by increasing the diameter of the blow-out holes or increasing the number of blow-out holes toward the tip of the blow-out duct, it is possible to level out the amount of heat from the gas supplied to the outside from the blow-out holes. In other words, it is possible to more reliably prevent the temperature control effect of the gas from decreasing toward the tip of the blow-out duct.

[0015] (4) In any of the above configurations (1) to (3), it is preferable that the duct length L0 of the blow-out duct is equal to or less than 3D / λ [m], where λ is the pipe friction coefficient of the blow-out duct.

[0016] In this way, the pressure (static pressure) inside the blow-out duct becomes substantially constant, so that the variation in the amount of gas blown out from the blow-out holes can be suppressed.

[0017] (5) The present invention, which has been invented to solve the above problems, is a temperature control method in which gas is supplied into the inside of an air blow-out duct from the base end side of the air blow-out duct, and the gas circulating inside the air blow-out duct is supplied to the outside of the air blow-out duct from a plurality of air blow-out holes arranged along the longitudinal direction of the air blow-out duct, wherein K is a value [1 / s] expressed by the following formula, and L0 is the duct length [m] of the air blow-out duct, and the inflow velocity of the gas at the base end of the air blow-out duct is more than 1 time K×L0 [m / s].

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[0018] In this way, the same effects as those of the corresponding configurations already described can be obtained.

[0019] (6) In the above configuration (5), it is preferable that the inflow velocity of the gas at the base end of the blow-off duct is more than 1 time and not more than 8 times K×L0 [m / s].

[0020] In this way, the same effects as those of the corresponding configurations already described can be obtained. Effect of the Invention

[0021] According to the present invention, it is possible to suppress a decrease in the temperature regulating effect of the gas as the distance approaches the tip end side of the blow-out duct. [Brief description of the drawings]

[0022] [Figure 1] 1 is a side view showing a temperature adjustment system according to an embodiment of the present invention. [Diagram 2] FIG. 1 is a diagram for explaining a simulation model. [Diagram 3] 10 is a conceptual diagram showing the relationship between the distance from the base end of the blow-out duct and the amount of gas blown out from the blow-out hole. FIG. [Figure 4] 1 is a schematic diagram showing the relationship between the distance x from the base end of the blow-out duct and the flow velocity V of gas in the blow-out duct. [Diagram 5]13 is a graph showing the relationship, obtained by simulation, between the distance x from the base end of the blow-off duct and the temperature difference T / T0 when m is changed. [Figure 6] 13 is a graph showing a relationship between the distance x from the base end of the blow-out duct and the temperature difference T / T0 obtained by simulation, and a relationship between the distance x from the base end of the blow-out duct and the correction coefficient f(x) obtained by simulation. [Figure 7] 1 is a side view showing a temperature adjustment system according to an embodiment of the present invention. [Figure 8] 8 is a cross-sectional view taken along the line PP in FIG. 7. [Figure 9] 1 is a graph showing measured and calculated values ​​of soil temperature distribution in a cultivation bed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0024] As shown in Fig. 1, the temperature control system 1 according to this embodiment includes a gas supplier 2 and a blow-out duct 3, and adjusts the temperature outside the blow-out duct 3. The temperature control system 1 can be widely used, for example, as an air conditioning system in a cultivation environment for plants such as strawberries, or an air conditioning system in a breeding environment for animals such as chickens. The temperature control system 1 can be used for both local temperature control and wide-area temperature control.

[0025] The gas supplier 2 supplies the gas G from the base end 3a side of the blow-out duct 3 to the inside of the blow-out duct 3. The gas supplier 2 supplies heated gas G when the outside of the blow-out duct 3 is to be heated (in the case of heating), and supplies cooled gas G when the outside of the blow-out duct 3 is to be cooled (in the case of cooling). The gas supplier 2 includes a fan (not shown) for compressing and sending the gas G to the inside of the blow-out duct 3. An air conditioner that supplies air as the gas G can be used as the gas supplier 2. As the gas G, for example, oxygen, nitrogen, inert gas, etc. can be used other than air. However, in consideration of ease of acquisition, etc., it is preferable that the gas G is air.

[0026] The blowing duct 3 is a straight pipe having a plurality of blowing holes 4 along the longitudinal direction. The proximal end 3a and the distal end 3b of the blowing duct 3 are each open. The blowing holes 4 are provided at equal intervals in the longitudinal direction. Inside the blowing duct 3, a gas G is supplied from the proximal end 3a side of the blowing duct 3. The gas G is supplied to the outside of the blowing duct 3 through each blowing hole 4 in the process of flowing through the inside of the blowing duct 3 from the proximal end 3a to the distal end 3b side of the blowing duct 3. Note that the blowing duct 3 may include a portion formed of a curved pipe.

[0027] And in the present embodiment, in order to suppress a decrease in the temperature control effect by the gas G as approaching the distal end 3b side of the blowing duct 3, the inflow velocity V0 of the gas G at the proximal end 3a of the blowing duct 3 is adjusted. Specifically, the inflow velocity V0 is adjusted to be m times (where 1 < m) of K×L0 [m / s], where K is a value [1 / s] represented by the following formula and L0 is the duct length [m] of the blowing duct.

[0028]

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[0029] From the viewpoint of suppressing a decrease in the temperature control effect by the gas G, the lower limit value of m is preferably 1.5 or more, more preferably 2 or more, further preferably 2.5 or more, and particularly preferably 3 or more. On the other hand, from the viewpoint of saving the supply energy and supply amount of the gas G, the upper limit value of m is preferably 24 or less, more preferably 8 or less, further preferably 7.5 or less, and particularly preferably 6 or less.

[0030] From the viewpoint of more surely suppressing a decrease in the temperature control effect by the gas G, the distribution of the opening area per unit length of the blowing holes 4 (the sum of the opening areas of the respective blowing holes 4 included per unit length) preferably satisfies the following formula.

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[0031] Furthermore, from the viewpoint of stabilizing the blown air volume per unit length of the blown duct 3, it is preferable that the duct length L0 of the blown duct 3 is equal to or less than 3D / λ [m], where λ is the pipe friction coefficient of the blown duct 3.

[0032] Next, the reasons for setting the inflow velocity V0 of the gas G, the distribution of the opening area per unit length of the blow-out hole 4, and the duct length L0 of the blow-out duct 3 as described above will be explained.

[0033] (Gas G inflow velocity V0) As shown in Figure 2, considering one section of the blow-out duct 3 defined by adjacent blow-out holes 4 in the longitudinal direction, the following equation is established from the relationship between the temperature drop of the gas G inside the blow-out duct 3 and the amount of heat dissipation from the surface of the blow-out duct 3.

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[0034] Δt=L / V k Therefore, the following equation is obtained from equation (3).

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[0035] Here, 4U / (C p Since the constant K is determined by the characteristics of the outlet duct 3, the following equation is obtained by expressing equation (4) as a differential equation.

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[0036] If the amount of gas G blown out from the blow-out hole 4 is uniform as shown in FIG. 3, the flow velocity V of the gas G in the blow-out duct 3 decreases in proportion to the distance x from the base end 3a of the blow-out duct 3 as shown in FIG. 4, and is expressed by the following formula.

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[0037] Equation (5) can be expressed as follows using equation (6).

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[0038]

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[0039] If the temperature difference between the inside and outside of the blow-out duct 3 at the base end 3a of the blow-out duct 3 is T0 [°C], then when x=0, T=T0, and the following equation is obtained from equation (8).

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[0040] If V0 is m times KL0, the following equation is obtained from equation (9).

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[0041] In other words, when V0 is m times KL0, the temperature difference T between the inside and outside of the blow-out duct 3 is proportional to the 1 / m power of the distance (L0-x) from the tip 3b of the blow-out duct 3.

[0042] FIG. 5 shows the change in temperature difference T / T0 when m is changed. From the figure, it can be seen that when m is 1 or less, that is, when the inflow velocity V0 of the gas G is KL0 [m / s] or less, the temperature difference T / T0 between the inside and outside of the blown dust 3 decreases as it approaches the tip 3b of the blown dust 3. This tendency is particularly noticeable as the value of m becomes smaller. On the other hand, when m is more than 1, that is, when the inflow velocity V0 of the gas G exceeds KL0 [m / s], it can be seen that the temperature difference T / T0 between the inside and outside of the blown dust 3 can be kept large up to the tip 3a of the blown dust 3. However, as m increases, the increase in the temperature difference T / T0 between the inside and outside of the blown dust 3 gradually decreases. Therefore, from the viewpoint of saving the supply energy (power consumption of the fan) and supply amount of the gas G, it is preferable that m is 24 or less.

[0043] (Distribution of opening area per unit length of blowing hole 4) The amount of heat P supplied per unit length of the discharge duct 3 is the sum of the amount of heat P1 supplied by the gas G blown out from the blowout holes 4 and the amount of heat P2 supplied by heat radiation from the duct surface of the discharge duct 3.

[0044]

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[0045] If V0 is m times KL0, the following equation is obtained from equation (11).

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[0046]

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[0047] K = 4U / (C p ρ·D), if V0 is set to m times KL0, the following equation is obtained from equation (13).

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[0048] Therefore, P1:P2=m:1, and it can be expressed using P as follows:

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[0049] Regarding the heat supply P1 by the gas G blown out from the blowing holes 4, the heat supply to each part can be expected to be leveled out by making the distribution of the opening area per unit length of the blowing holes 4 in each part the reciprocal of the temperature difference inside and outside the blowing duct 3 in each part. Therefore, without changing the total air volume, the opening area per unit length of the blowing holes 4 is made the distribution of the reciprocal of P1 expressed by formula (12) (normalized by placing the average value in the denominator).

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[0050] The denominator of this correction coefficient f(x) is m / (m-1) when m>1, so the following equation is obtained from equation (17): Note that when m≦1, the denominator of the correction coefficient f(x) is infinite, and this correction cannot be performed.

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[0051] Fig. 6 shows the relationship between the temperature difference T / T0 and the correction coefficient f(x). From this figure, it can be seen that the amount of heat from the gas supplied to the outside from the blowing holes 4 can be equalized by adjusting the blowing flow rate at each point by increasing the hole diameter of the blowing holes 4 or increasing the number of blowing holes 4 toward the tip of the blowing duct 3 based on the correction coefficient f(x). Note that the amount of heat from the gas supplied to the outside from the blowing holes 4 can also be equalized by adjusting the area per unit length of the blowing holes 4 based on the correction coefficient f(x) multiplied by a constant (A x f(x)).

[0052] It is also known that the loss coefficient at the blowing hole 4 differs depending on the shape of the blowing hole 4, and the difference in the loss coefficient due to the shape of each blowing hole 4 may be taken into account in adjusting the blowing flow rate from each blowing hole 4. In other words, the static pressure in the blowing duct 3 at each blowing hole 4 is assumed to be proportional to the square of the blowing speed and the loss coefficient. For example, the loss coefficient of a circular blowing hole 4 is 2.5, and the loss coefficient of a blowing hole to which a nozzle (e.g. a cylindrical member) of sufficient length is added is assumed to be 0.34. In this case, (2.5 / 0.34) 1 / 2 = 2.71, adding a nozzle is equivalent to increasing the area of ​​the blowing hole 4 by 2.71 times.

[0053] (Duct length L0 of outlet duct 3) The static pressure Ps [Pa] in the outlet duct 3 is expressed by the following formula according to Bernoulli's law.

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[0054] Here, P T is the static pressure [Pa] in the blow-out duct 3 at the tip 3b of the blow-out duct 3. The flow velocity V of the gas G in the blow-out duct 3 is n(L0-x), where n is the coefficient (V0 / L0).

[0055] The first term of equation (19) represents the integral between x and L0 when the pressure loss per unit length in the discharge duct 3 is given by equation (20). The second term of equation (19) represents the decrease in static pressure in the discharge duct 3 due to the dynamic pressure in the discharge duct 3.

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[0056] The range in which the blowing volume of the gas G from the blowing hole 4 can be considered uniform is obtained. In the formula (19), Ps = P T The points at which this holds true are x=L0 and x=L0-3D / λ. That is, in the range of 3D / λ from the tip 3b of the blow-out duct 3, the volume of air blown out from the blow-out hole 4 is substantially constant. Therefore, it is understood that the duct length L0 of the blow-out duct 3 is preferably set to 3D / λ or less.

[0057] Next, a temperature control method according to this embodiment will be described.

[0058] The temperature control method according to this embodiment uses the above-described temperature control system 1. In detail, the temperature control method according to this embodiment includes a first step of supplying gas G from the base end 3a side of the blow-out duct 3 into the inside of the blow-out duct 3, and a second step of supplying the gas G flowing inside the blow-out duct 3 to the outside of the blow-out duct 3 from a plurality of blow-out holes 4 provided along the longitudinal direction of the blow-out duct 3.

[0059] In the first step, the inflow velocity V0 of the gas G at the base end 3a of the blow-out duct 3 is adjusted to be more than 1 time (preferably 1.5 times or more and 24 times or less) of K×L0 [m / s]. The inflow velocity V0 can be adjusted, for example, by the flow rate of the gas G supplied from the gas supplier 2. In this way, the temperature difference between the inside and outside of the blow-out duct 3 (the difference between the temperature of the gas G in the blow-out duct 3 and the temperature of the atmosphere outside the blow-out duct 3) can be suppressed from decreasing as the tip 3b of the blow-out duct 3 approaches. As a result, in the second step, the temperature control effect of the gas G can be suppressed from decreasing as the tip 3b of the blow-out duct 3 approaches. In addition, if the inflow velocity V0 of the gas G is set to 24 times or less of K×L0 [m / s], the inflow velocity V0 of the gas G at the base end 3a of the blow-out duct 3 can be suppressed to the minimum necessary, so that the supply energy (power consumption) and supply amount of the gas G can be saved.

[0060] The present invention is not limited to the configuration of the above embodiment, nor is it limited to the above-mentioned effects and advantages. Various modifications of the present invention are possible without departing from the spirit and scope of the present invention.

[0061] In the above embodiment, the duct length L0 of the blow-out duct 3 may be more than 3D / λ. In this case, it is preferable to make the opening area per unit length of the blow-out hole 4 in the base end 3a side portion exceeding 3D / λ from the tip 3b of the blow-out duct 3 smaller than the opening area per unit length of the blow-out hole 4 in the tip end 3a side portion within 3D / λ from the tip 3a of the blow-out duct 3.

[0062] In the above embodiment, the temperature adjustment system 1 may further include a suction duct having a plurality of suction holes along the longitudinal direction in order to recover the gas G supplied by the blow-out duct 3 to the gas supplier 2. EXAMPLES

[0063] As shown in Figs. 7 and 8, a temperature adjustment system 1 according to the embodiment is an air conditioning system for cultivated crops such as strawberries.

[0064] The temperature control system 1 includes a long cultivation bed 6 in which a large number of cultivated crops 5 are planted, a gas supplying machine 2 arranged on the base end (base end 3a of the blow-out duct 3) side of the cultivation bed 6, and a blow-out duct 3 arranged so as to extend from the gas supplying machine 2 along the cultivation bed 6, and the gas G from the gas supplying machine 2 is pumped to the blow-out duct 3 and supplied to the cultivated crops 5 from the blow-out holes 4 of the blow-out duct 3. A film member 7 made of a vinyl sheet or the like is provided so as to surround the cultivation bed 6 and the blow-out duct 3 so that the gas G from the gas supplying machine 2 can be supplied to the cultivated crops 5 planted in the cultivation bed 6 by the blow-out duct 3.

[0065] The blowing duct 3 is a paper void pipe.

[0066] The gas supplier 2 is an air conditioner and supplies heated air as the gas G.

[0067] The conditions of the temperature control system 1 are shown in Table 1. [Table 1]

[0068] The relationship between the measured soil temperature distribution (temperature difference from the comparison row) in cultivation bed 6 and the calculated value T estimated using equation (10) is shown in Figure 9. The measured values ​​are average values ​​at 3:00 a.m. over four days in November, and are the temperature difference from the average soil temperature of the comparison row, which was 15.2°C.

[0069] The length of this blow-out duct is approximately equivalent to 3D / λ, and the temperature distribution of the heated cultivation bed almost coincides with the calculated value except at both ends. In addition, if the inflow velocity V0 of the gas G is made more than 1 time K×L0 [m / s], the decrease in the temperature control effect due to the decrease in the temperature difference inside and outside the blow-out duct 3 is suppressed, and it is found that the temperature decrease in the longitudinal direction of the cultivation bed 6 can be suitably suppressed. Note that the soil temperature at both ends of the longitudinal direction of the cultivation bed 6 is a value influenced by the surrounding soil and room temperature. [Explanation of symbols]

[0070] 1 Temperature control system 2 Gas supply machine 3. Exhaust duct 4 Air outlet 5 Cultivated crops 6. Cultivation Beds 7 Film materials

Claims

1. a blow-out duct having a plurality of blow-out holes along a longitudinal direction; and a gas supplier that supplies gas from a base end side of the blow-out duct to an inside of the blow-out duct, A temperature control system that circulates the gas inside the blow-out duct and supplies the gas to the outside of the blow-out duct from the blow-out hole, Let K be the value [1 / s] expressed by the following formula, and L ０ is the length of the blow-out duct [m], The inflow velocity of the gas at the base end of the blow-out duct is K×L ０ A temperature control system characterized in that the temperature is adjusted to m times [m / s] (where m>1). [0010]

2. The inflow velocity of the gas at the base end of the blow-out duct is K×L ０ The temperature control system according to claim 1, wherein the temperature control system is adjusted to be 1.5 to 24 times the speed of the air flow.

3. The temperature adjustment system according to claim 1 or 2, wherein a distribution of an area per unit length of the blowing holes satisfies the following formula: [0025]

4. When λ is the pipe friction coefficient of the blowout duct, The duct length L of the blowout duct ０ The temperature control system according to claim 1 or 2, wherein the distance is 3D / λ [m] or less.

5. When λ is the pipe friction coefficient of the blowout duct, The duct length L of the blowout duct ０ The temperature control system according to claim 3 , wherein the distance is 3D / λ [m] or less.

6. A temperature control method for supplying a gas into an inside of an air outlet duct from a base end side of the air outlet duct, and supplying the gas flowing through the inside of the air outlet duct to an outside of the air outlet duct from a plurality of air outlet holes provided along a longitudinal direction of the air outlet duct, Let K be the value [1 / s] expressed by the following formula, and L ０ is the duct length [m] of the blowing duct, The inflow velocity of the gas at the base end of the blow-out duct is K×L ０ A temperature control method, characterized in that the temperature is greater than 1 [m / s]. [0030]

7. The inflow velocity of the gas at the base end of the blow-out duct is K×L ０ The temperature control method according to claim 6, wherein the temperature control is performed in a range of 1.5 to 24 times the normal speed [m / s].

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