CN104303905B - A kind of heliogreenhouse local cooling system and based on its cool-down method - Google Patents

Abstract

The invention belongs to greenhouse facility field, be specifically related to a kind of heliogreenhouse local cooling system and the cool-down method based on it.This heliogreenhouse Local Air-cooling System, including air-cooler, pipe-line system and jacking system；Air-cooler is arranged on outside the rear wall in greenhouse, arranges pipe-line system and jacking system in heliogreenhouse；The main pipeline of pipe-line system is connected with the air outlet of air-cooler, and some horizontal branch pipe roads of pipe-line system are connected with main pipeline by vertical telescoping tube；Jacking system drives horizontal branch pipe road to lift at vertical direction；Described horizontal branch pipe road has air port；When normal ventilation can not maintain preference temperature in greenhouse, determine air-cooler and each pipe parameter according to cooling demand；Open cold blower fan, the height according to the height adjustment levels branch pipe(tube) of crop, keep best cooling-down effect.Utilize this system can effectively reduce the ambient temperature of influences of plant crown top local, and thermograde is little, energy consumption is low, extend the greenhouse production time in summer.

Description

A kind of heliogreenhouse local cooling system and based on its cool-down method

Technical field

The invention belongs to greenhouse facility field, be specifically related to a kind of heliogreenhouse local cooling system and the cool-down method based on it.

Background technology

Green house, as the main body in China's industrialized agriculture industry, has become industry most effective in agricultural planting industry in recent years.Green house be solve the vegetable in long-standing problem the northern area of China winter supply dull season, increase farmers' income, save the energy, promote agricultural sector structure adjustment, drive related industry, development dispose obtain employment, the environmental pollution etc. of avoiding greenhouse heating to cause all is made that significant contribution.

Heliogreenhouse has energy-conserving and environment-protective, can make full use of idle land and the remarkable advantage of labour force in winter.In Gray in Sunlight Greenhouse in Summer, temperature is too high is unfavorable for plant growth, thus causing that heliogreenhouse left unused in summer, reduces land utilization ratio, with the modernization development direction grave fault of heliogreenhouse facility.The problem in short supply along with land resource is outstanding day by day, improves heliogreenhouse anniversary utilization rate and has become the great research topic urgently to be resolved hurrily of China's agricultural facility scientific research and agricultural production.

How when reducing energy consumption, reduce the temperature in Gray in Sunlight Greenhouse in Summer, provide suitable growing environment for crop, improve heliogreenhouse anniversary utilization rate, be problem demanding prompt solution.

Summary of the invention

It is an object of the invention to the temperature reducing in Gray in Sunlight Greenhouse in Summer when reducing energy consumption, it is provided that a kind of heliogreenhouse local cooling system and the cool-down method based on it.

For solving the problems referred to above, technical scheme is as follows: a kind of heliogreenhouse local cooling system, including air-cooler, pipe-line system and jacking system.Air-cooler is arranged on the exterior wall of heliogreenhouse, arranges pipe-line system and jacking system in heliogreenhouse.The main pipeline of pipe-line system is connected with the air outlet of air-cooler, and some horizontal branch pipe roads of pipe-line system are connected with main pipeline by vertical telescoping tube.Jacking system drives horizontal branch pipe road to lift at vertical direction.Described horizontal branch pipe road has air port.

Described main pipeline is variable cross-section rectangular air duct, to ensure to have in horizontal branch pipe road identical pressure and flow.Main pipeline hard PVC sheet material is spliced.

Described vertical telescoping tube comprises film tube and the collar.Outer surface at film tube equidistantly fixes iron hoop, and the gravity by iron hoop drives film tube to stretch.

Described horizontal branch pipe road is transparent plastic film pipe, and the first-class spacing in horizontal branch pipe road offers air port, and air port is non-isometrical circular hole, makes each tuyere air volume consistent, it is achieved uniform ventilation.Each air port does not face plant, and Shang Ge air port, horizontal branch pipe road becomes 60 degree of angles with perpendicular, is distributed along both sides, axis indention.Described horizontal branch pipe road is equidistantly distributed in the top of heliogreenhouse institute kind of plant canopy.

Described air-cooler is wet curtain air-cooler, it is necessary to select suitable air-cooler product according to the ventilation needed for heliogreenhouse and blast.

Described jacking system comprises back(ing) bar, pull rope, support axle, rotates axle and reducing motor.Back(ing) bar and described horizontal branch pipe road are fixed.One end of pull rope connects back(ing) bar, and the other end is walked around support axle and is wound around on the rotating shaft.Reducing motor drives and rotates axle rotation.The lifting of back(ing) bar is realized, thus the height realizing horizontal branch pipe road can change with the change of plant height by pull rope.Described back(ing) bar is aluminum alloy square tube.

Two pull ropes are connected with the two ends of back(ing) bar respectively, and the other end of two pull ropes is all walked around respective support axle and is wound around on the rotating shaft.

Cool-down method based on heliogreenhouse local cooling system: when gravity-flow ventilation can not maintain ambient temperature suitable in heliogreenhouse, install air-cooler and each pipeline；Open cold blower fan, the cold wind produced by air-cooler sequentially passes through main pipeline, vertical telescoping tube and horizontal branch pipe road and the regional area of plant canopy is lowered the temperature, particularly the regional area such as growing point and spica is lowered the temperature, and the normal growth being beneficial to these organs is grown.During cooling, height according to crop drives horizontal branch pipe road to lift at vertical direction by jacking system, horizontal branch pipe road 15cm to 20cm above plant canopy, regulates the level height in horizontal branch pipe road, keeps best cooling-down effect with the height change of the growing point of crop；After cooldown period terminates, described vertical telescoping tube, horizontal branch pipe road and back(ing) bar are pulled down preservation, has both been avoided that the working place taking in heliogreenhouse, the service life of heliogreenhouse local cooling system can be extended again.

By the following method, it is determined that the parameter of air-cooler:

The solar irradiance arriving daylight inside greenhouse is about 300W/m²Heliogreenhouse is of a size of s, and the cold air density of air-cooler is ρ, air themperature that wet curtain air-cooler provides and to make the enthalpy difference of air under surrounding plants air themperature state be Δ h, according to formula: Q × ρ × Δ h × 1000/3600=300 × s, calculate and obtain required ventilation Q.

The method determining the size of main pipeline is:

Being Q according to ventilation, have N ridge culture thing in heliogreenhouse, each air port air output obtaining main pipeline is Q/N, and every ridge culture thing has each self-corresponding vent.

Each air port of selected main pipeline average out Flow Velocity v0, then the area of air outlet isObtaining the diameter d of air outlet, the static pressure flow velocity of air outlet isThe due static pressure of air outlet:

$p_i=\frac{{p_i}^2\mathrm{\ρ}}{2}$

The air of wind Bottomhole pressure is subject to hydrostatic pressure in tube wall vertical direction, after tube wall perforate, due to the effect of differential static pressure inside and outside aperture, air can flow out from aperture in vertical tube wall direction, due to the impact being subject in primary tube axial flow velocity, orifice outflow direction is along airduct axis direction at an angle.For ensure Uniform Ventilation, it is desirable to make first air outlet go out to flow angle [alpha] >=60 °.

Air axial flow velocity in airduct is:

$v_d=\sqrt{\frac{2p_d}{\mathrm{\ρ}}}$

In formula, p_dThe dynamic pressure (Pa) of wind inner air tube flowing.

For keeping air-flow angle α >=60 °, make v_i≥1.73v_d, thus selected v_d.If first air port place inner air tube flow velocity v_d1。

The dynamic pressure at first air port place:

$p_{d1}=\frac{{v_{d1}}^2\mathrm{\ρ}}{2}$

According toObtain the diameter D of first air port place main pipeline₁。

The total head at first air port place:

p_q1=p₁+p_d1

Resistance between first air outlet of run of designing and second air outlet, obtains the total head at second air outlet place, and described resistance includes on-way resistance and air outlet local resistance.

The calculating of on-way resistance:

Reynolds numberWherein, υ is air movement viscosity, value when taking 20 DEG C.

In pipe, flowing belongs to turbulent flow water conservancy smooth areas, and frictional resistant coefficient is

On-way resistance is:

$f_{f1}=\mathrm{\λ}\frac{l}{D_1}\frac{v_{d1}}{2g}$

The calculating of local resistance:

On-way resistance is:

f_f1=ξ p_d1

Wherein, ξ is local resistance coefficient.

The total head at second air port place:

p_q2=p_q1-f_f1-f_j1

According to p_q2Obtain p_d2, thus calculating the diameter at second air port place.

In pipeline, the static pressure of each section is equal, is p_i, therefore the dynamic pressure at second air port place is:

p_d2=p_q2-p_j

The flow velocity at second air port place is:

$v_{d2}=\sqrt{\frac{2p_{d2}}{\mathrm{\ρ}}}$

According toObtain section 2 diameter D₂。

The like, all the other each pipeline section resistances can be calculated respectively, try to achieve the diameter of all the other each air port place main pipelines.The diameter more than tried to achieve is Flowing speed equivalent diameter, with rectangular air duct length of side relation is

The Size calculation process in horizontal branch pipe road is:

Horizontal branch pipe road adopts constant section duct side-wall hole, and static pressure is gradually increased along its length, for air quantity balanced ventilations such as realizations, need to change side opening area.Assuming that discharge coefficient and frictional resistant coefficient are constant, air channel length is L, and duct cross-section amasss as A, and the distance between each air port is equal.Air port Peak Flow Rate is v_max, arable farming requiring to determine, conduit entrance section air quantity is Q0.From pipe end to import, to each air port number consecutively, i+1 air port area is

$v_{i+1}=u\sqrt{\frac{2}{\mathrm{\ρ}}{p}_{i+1}}$

σ in formula_i+1I+1 air port area, m²；

Q0 pipeline air intake section flow, m³/ s；

v_i+1The wind speed in i+1 air port, m/s；

ρ atmospheric density, kg/m³；

U air port discharge coefficient；

p_i+1Pipeline is at i+1 air port place static air pressure, Pa；

N inlet number.

To central section row energy equation between i+1 air port and No. i-th air port,

$p_{i+1}=p_i-\frac{{\mathrm{\ρw}}_{i+1}^2}{2}+\frac{{\mathrm{\ρw}}_i^2}{2}+{\mathrm{\Δp}}_i$

Δ p in formula_iOn-way resistance between i+1 air port and No. i-th air port, Pa；

w_i、w_i+1The respectively air velocity in No. i-th air port and i+1 air port pipeline, m/s；

Wherein,

Due to balanced ventilation, then have

$Q_{i+1}=\frac{Q}{A}(i+1)$

$Q_i=\frac{Q_0}{A}i$

$w_{i+1}=\frac{Q_0(i+1)}{nA}$

$w_i=\frac{Q_{0}i}{nA}$

${\mathrm{\ΔP}}_i={\∫}_0^{L/n}\frac{{\mathrm{\λ\ρw}}_i^2}{2D}dx=\frac{{\mathrm{\λ\ρQ}}_0^2{i}^{2}L}{2n^3{A}^{2}D}$

λ frictional resistant coefficient in formula；

L air channel length, m；

D pipeline equivalent diameter, m.

Solve above various, air port area can be obtained；

${\mathrm{\σ}}_{i+1}=\frac{1}{\sqrt{\frac{1}{{\mathrm{\σ}}_1^2}-\frac{u^2}{A^2}(i^2-1-\frac{\mathrm{\λ}L}{nD}{\mathrm{\Σ}}_{i=1}^{i-1}{i}^2)}}$

No. 1 air port area at pipe end place is minimum, and No. n-th air port area of conduit entrance place is maximum.

Number one air port area is

${\mathrm{\σ}}_i=\frac{Q_0}{{\mathrm{mv}}_{i+1}}=\frac{Q_0}{{\mathrm{nv}}_{max}}$

Wind speed for ensureing No. n-th air port of conduit entrance place reaches certain value, and tail end air port flow velocity should meet:

v_n> v_min

$v_{min}=\frac{Q_{0}u}{An}\sqrt{n^2-1-\frac{\mathrm{\λ}L}{nD}\underset{i=1}{\overset{n-1}{\Σ}}{i}^2}$

Beneficial effects of the present invention

Compared with prior art, the invention have the advantages that and utilize this heliogreenhouse local cooling system can effectively reduce influences of plant crown top local environment temperature, and thermograde is little, energy consumption is low, extend the heliogreenhouse production time in summer, for improving land utilization ratio, increasing investor income has positive meaning.

Accompanying drawing explanation

Fig. 1: the front view of heliogreenhouse local cooling system；

Fig. 2: the top view of heliogreenhouse local cooling system；

Fig. 3: the left view of heliogreenhouse local cooling system；

Fig. 4: the schematic diagram of the jacking system of heliogreenhouse local cooling system；

Fig. 5: the schematic diagram of vertical telescoping tube；

Fig. 6: the schematic cross-section of main pipeline；

Fig. 7: the air port schematic diagram in horizontal branch pipe road

1 wet curtain air-cooler, 2 main pipelines, 3 vertical telescoping tubes, 4 horizontal branch pipe roads, 5 back(ing) bars, 6 pull ropes, 7 rotate axle, and 8 support axle, 9 reducing motors, 10 safety buckles, 11 film tubes, 12 iron hoops, 13 pallets.

Detailed description of the invention

Below in conjunction with the drawings and specific embodiments, the present invention will be further described.

A kind of heliogreenhouse local cooling system, it is characterised in that include wet curtain air-cooler 1, pipe-line system and jacking system.

As shown in Figure 1, Figure 2 and Figure 3, wet curtain air-cooler 1 is arranged on the outside of heliogreenhouse north wall, it is necessary to select suitable air-cooler product according to the ventilation needed for system and blast.The main pipeline 2 of pipe-line system is fixed on the inner side of heliogreenhouse north wall, and thing extends.Main pipeline 2 is connected with the air outlet of wet curtain air-cooler 1, and some horizontal branch pipe roads 4 of pipe-line system are connected with main pipeline 2 by vertical telescoping tube 3.Vertical telescoping tube 3 is arranged on below main pipeline 2.Horizontal branch pipe road 4 is arranged along north-south, heliogreenhouse span direction, is placed in above 15cm to the 20cm place of crop plant canopy.

As shown in Figure 6, main pipeline 2 is variable cross-section rectangular air duct, to ensure to have in horizontal branch pipe road 4 identical pressure and flow.Main pipeline 2 hard PVC sheet material is spliced.

As it is shown in figure 5, described vertical telescoping tube 3 comprises film tube 11, the collar 12 and pallet 13.Outer surface at film tube 11 equidistantly fixes iron hoop 12, and the gravity by iron hoop 12 drives film tube 11 to stretch, at the pallet 13 of a circle arranged below of vertical telescoping tube 3, it is possible to support the iron hoop 12 fallen.Fig. 5 left part is that vertical telescoping tube 3 is in extended configuration, and Fig. 5 left part is that vertical telescoping tube 3 is in contraction state.

As it is shown in fig. 7, described horizontal branch pipe road 4 is transparent plastic film pipe, horizontal branch pipe road 4 equidistantly offering air port, air port is non-isometrical circular hole, makes each tuyere air volume consistent, it is achieved uniform ventilation.Each air port does not face plant, and on horizontal branch pipe road 4, each air port becomes 60 degree of angles with perpendicular, is distributed along both sides, axis indention.Described horizontal branch pipe road is equidistantly distributed in the top of heliogreenhouse institute kind of plant canopy.

As shown in Figure 4, described jacking system comprises back(ing) bar 5, pull rope 6, supports axle 8, rotates axle 7 and reducing motor 9.Back(ing) bar 5 is fixed with described horizontal branch pipe road 4.One end of two pull ropes 6 connects back(ing) bar 5, and the other end is all walked around respective support axle 8 and is wrapped on rotation axle 7.Reducing motor 9 drives rotation axle 7 to rotate.The lifting of back(ing) bar 5 is realized, thus the height realizing horizontal branch pipe road 4 can lift with the change of plant height by pull rope 6.

Described back(ing) bar 5 is aluminum alloy square tube.

Heliogreenhouse cool-down method based on heliogreenhouse local cooling system, when normal gravity-flow ventilation can not maintain ambient temperature suitable in heliogreenhouse, determine the parameter of wet curtain air-cooler 1 and each line size according to cooling demand, wet curtain air-cooler 1 and each pipeline are installed.

Open cold blower fan, air-cooler plant canopy, the particularly regional area such as growing point and spica are lowered the temperature by the cold wind produced, and the normal growth being beneficial to these organs is grown.During cooling, need to according to the height of the height adjustment levels branch pipe(tube) of crop, horizontal branch pipe road 15cm to 20cm above plant canopy, regulate with the height change of growing point of crop, keep best cooling-down effect.

After cooldown period terminates, described vertical telescoping tube, horizontal branch pipe road and back(ing) bar are pulled down preservation, has both been avoided that the working place taking in heliogreenhouse, the service life of heliogreenhouse local cooling system can be extended again.

Due to this heliogreenhouse local cooling system, its technological core is the temperature of the localized area reducing plant, but not the temperature in whole greenhouse, so native system compares the cooling being suitable for the organ such as growing point, bud to the more sensitive crop of temperature, such as Fructus Cucumidis sativi, Fructus Lycopersici esculenti, Fructus Solani melongenae, fresh kidney beans etc..In the different phase of plant growth, according to plant, the demand of temperature is run system in time, the temperature environment suitable to maintain crop.Height change according to crop, adjusts the height of horizontal branch pipe in time, keeps best cooling-down effect.

Embodiment

In China Agricultural University in the heliogreenhouse of proving ground, the village, a set of " heliogreenhouse local cooling system " is installed.The long 60m of heliogreenhouse thing, span 8.0m, ridge height 4.0m, rear wall height 2.8m, rear wall thickness 0.67m, rear roofing extent of horizontal projection degree is 1.5m, adopts steel truss structure, truss space 1m, planting in solar-greenhouse Fructus Lycopersici esculenti, totally 40 ridge, row spacing 0.5m, spacing 1.0m between ridge.

(1) system design and installation

The parameter of wet curtain air-cooler and each line size is determined: take outdoor mean temperature 30 DEG C, relative humidity 58%, make surrounding plants air themperature 26 DEG C, relative humidity 85% according to cooling demand.According to formula Q × ρ × Δ h × 1000/3600=300 × s, obtain total ventilation and be about 12000m³/ h, adopts two typhoon amount 6000m³/ h, static pressure 254Pa blower fan.

The Size calculation process of main pipeline is:

It is 6000m according to ventilation³/ h, is 20 ridge culture thing supply cold wind, and each air port air output obtaining main pipeline is 300m³/ h.Cross section such as Fig. 6 of the main pipeline at main pipeline 2 each air port place.

Each air port of selected main pipeline average out Flow Velocity v0=11m/s, then the area of air outlet isThe diameter obtaining air outlet is 10cm, and the static pressure flow velocity of air outlet isThe due static pressure of air outlet:

$p_i=\frac{{p_i}^2\mathrm{\ρ}}{2}=194Pa$

The air of wind Bottomhole pressure is subject to hydrostatic pressure in tube wall vertical direction, after tube wall perforate, due to the effect of differential static pressure inside and outside aperture, air can flow out from aperture in vertical tube wall direction, due to the impact being subject in primary tube axial flow velocity, orifice outflow direction is along airduct axis direction at an angle.For ensure Uniform Ventilation, it is desirable to make first air outlet go out to flow angle [alpha] >=60 °.

Air axial flow velocity in airduct is:

$v_d=\sqrt{\frac{2p_d}{\mathrm{\ρ}}}$

In formula, p_dThe dynamic pressure (Pa) of wind inner air tube flowing.

For keeping air-flow angle α >=60 °, make v_i≥1.73v_d, thus selected v_d=10m/s.If first air port place inner air tube flow velocity v_d1。

The dynamic pressure at first air port place:

$p_{d1}=\frac{{v_{d1}}^2\mathrm{\ρ}}{2}=60Pa$

According toObtain the diameter D of first air port place main pipeline₁For 0.31m.

The total head at first air port place:

p_q1=p₁+p_d1=254Pa

Resistance between first air outlet of run of designing and second air outlet, obtains the total head at second air outlet place, and described resistance includes on-way resistance and air outlet local resistance.

The calculating of on-way resistance:

Reynolds numberWherein, υ is air movement viscosity, the value 15.7 × 10 when taking 20 DEG C^-6m²s^-1。

In pipe, flowing belongs to turbulent flow water conservancy smooth areas, and frictional resistant coefficient is

On-way resistance is:

$f_{f1}=\mathrm{\λ}\frac{l}{D_1}\frac{v_{d1}}{2g}$

The calculating of local resistance:

On-way resistance is:

f_f1=ξ p_d1

Wherein, ξ is local resistance coefficient, can look into following table.

Table 1 local resistance coefficient table

qv0/qv	0	0.1	0.2	0.3	0.4	0.5	0.6	0.7	0.8	0.9	1
												ξ	0.15	0.05	0.02	0.01	0.03	0.07	0.12	0.17	0.23	0.29	0.35

The total head at second air port place:

p_q2=p_q1-f_f1-f_j1

According to p_q2Obtain p_d2, thus calculating the diameter at second air port place.

In pipeline, the static pressure of each section is equal, is p_i, therefore the dynamic pressure at second air port place is:

p_d2=p_q2-p_j

The flow velocity at second air port place is:

$v_{d2}=\sqrt{\frac{2p_{d2}}{\mathrm{\ρ}}}$

According toObtain section 2 diameter D₂。

The like, all the other each pipeline section resistances can be calculated respectively, try to achieve the diameter of all the other each air port place main pipelines.The diameter more than tried to achieve is Flowing speed equivalent diameter, with rectangular air duct length of side relation is

The sectional dimension of main pipeline such as table 2.

The each section calculation result of table 2 main pipeline

Section	1	2	3	4	5	6	7	8	9	10
											D/mm	330	313	299	283	266	245	221	192	158	114
a│b/cm	30│36	30│33	30│30	30│27	30│24	30│21	30│17	30│14	30│11	30│7
											Static pressure/Pa	194	194	194	194	194	194	194	194	194	194
Dynamic pressure/Pa	60	57	54	51	49	47	46	44	43	39
											Total head/Pa	254	251	248	245	243	241	240	238	237	233

The Size calculation process in horizontal branch pipe road is:

Horizontal branch pipe road adopts constant section duct side-wall hole, and static pressure is gradually increased along its length, for air quantity balanced ventilations such as realizations, need to change side opening area.Assuming that discharge coefficient and frictional resistant coefficient are constant, air channel length is L, and duct cross-section amasss as A, and the distance between each air port is equal.Air port Peak Flow Rate is v_max, arable farming requiring to determine, conduit entrance section air quantity is Q0.From pipe end to import, to each air port number consecutively, i+1 air port area is

$v_{i+1}=u\sqrt{\frac{2}{\mathrm{\ρ}}{p}_{i+1}}$

σ in formula_i+1I+1 air port area, m²；

Q0 pipeline air intake section flow, m³/ s；

v_i+1The wind speed in i+1 air port, m/s；

ρ atmospheric density, kg/m³；

U air port discharge coefficient；

p_i+1Pipeline is at i+1 air port place static air pressure, Pa；

N inlet number.

To central section row energy equation between i+1 air port and No. i-th air port,

$p_{i+1}=p_i-\frac{{\mathrm{\ρw}}_{i+1}^2}{2}+\frac{{\mathrm{\ρw}}_i^2}{2}+{\mathrm{\Δp}}_i$

Δ p in formula_iOn-way resistance between i+1 air port and No. i-th air port, Pa；

w_i、w_i+1The respectively air velocity in No. i-th air port and i+1 air port pipeline, m/s；

Wherein,

Due to balanced ventilation, then have

$Q_{i+1}=\frac{Q}{A}(i+1)$

$Q_i=\frac{Q_0}{A}i$

$w_{i+1}=\frac{Q_0(i+1)}{nA}$

$w_i=\frac{Q_{0}i}{nA}$

${\mathrm{\ΔP}}_i={\∫}_0^{L/n}\frac{{\mathrm{\λ\ρw}}_i^2}{2D}dx=\frac{{\mathrm{\λ\ρQ}}_0^2{i}^{2}L}{2n^3{A}^{2}D}$

λ frictional resistant coefficient in formula；

L air channel length, m；

D pipeline equivalent diameter, m.

Solve above various, air port area can be obtained；

${\mathrm{\σ}}_{i+1}=\frac{1}{\sqrt{\frac{1}{{\mathrm{\σ}}_1^2}-\frac{u^2}{A^2}(i^2-1-\frac{\mathrm{\λ}L}{nD}{\mathrm{\Σ}}_{i=1}^{i-1}{i}^2)}}$

No. 1 air port area at pipe end place is minimum, and No. n-th air port area of conduit entrance place is maximum.

Number one air port area is

${\mathrm{\σ}}_i=\frac{Q_0}{{\mathrm{mv}}_{i+1}}=\frac{Q_0}{{\mathrm{nv}}_{max}}$

Wind speed for ensureing No. n-th air port of conduit entrance place reaches certain value, and tail end air port flow velocity should meet:

v_n> v_min

$v_{min}=\frac{Q_{0}u}{An}\sqrt{n^2-1-\frac{\mathrm{\λ}L}{nD}\underset{i=1}{\overset{n-1}{\Σ}}{i}^2}$

Horizontal branch pipe road D=0.15m, Q₀=0.083m³/ s, n=24, L=6m, λ=0.026, u=0.62, air port size such as table 3.

Table 3 branch pipe(tube) each aperture parameter result of calculation

Air port number	1	2	3	4	5	6	7	8
									Diameter (cm)	3.8	3.8	3.8	3.9	3.9	3.9	3.9	3.9
Tuyere velocity (m/s)	3.0	1.9	1.9	1.9	1.9	1.8	1.8	1.8
									Static pressure (Pa)	10.8	4.3	4.3	4.2	4.2	4.1	4.0	3.9
Air port number	9	10	11	12	13	14	15	16
									Diameter (cm)	4.0	4.0	4.0	4.0	4.1	4.1	4.2	4.2
Tuyere velocity (m/s)	1.8	1.8	1.7	1.7	1.7	1.6	1.6	1.6 9 -->
									Static pressure (Pa)	3.8	3.7	3.6	3.5	3.3	3.2	3.0	2.9
Air port number	17	18	19	20	21	22	23	24
									Diameter (cm)	4.3	4.4	4.4	4.5	4.6	4.7	4.8	4.9
Tuyere velocity (m/s)	1.5	1.5	1.4	1.4	1.3	1.3	1.2	1.1
									Static pressure (Pa)	2.7	2.6	2.4	2.2	2.1	1.9	1.7	1.6

As seen from the above table, each tuyere diameter is between 3.8cm to 4.9cm, wind speed is in 1.1m/s to 3.0m/s scope, owing to plant surface wind speed is not preferably greater than 1m/s, therefore perforate direction, each air port should not face plant, the each air port of plastic sheeting airduct becomes 60 degree of angles with perpendicular, is distributed along both sides, axis indention, as shown in Figure 7.

As it is shown in figure 5, the outer surface at film tube 11 equidistantly fixes 150mm iron hoop 12, the gravity by iron hoop 12 drives film tube 11 to stretch, at the pallet 13 of a circle arranged below of vertical telescoping tube 3, it is possible to support the iron hoop 12 fallen.

Wet curtain air-cooler 1 and each pipe arrangement schematic diagram are as shown in Figure 1, Figure 2 and Figure 3.

Back(ing) bar 5 adopts 30mm × 10mm × 1.0mm aluminum alloy square tube.Pull rope 6 adopts the soft nylon rope of diameter 2mm.Rotating axle 7 and all adopt external diameter 5mm with supporting axle 8, wall thickness is 1.5mm hot galvanized steel pipe.Adopting the miniature turbine worm speed-down direct current generator of GW4468 type, rated speed is 8r/min, nominal torque 100kg cm.

(2) based on the cool-down method of this system

When normal gravity-flow ventilation can not maintain ambient temperature suitable in heliogreenhouse, the cold wind produced by air-cooler 1 sequentially passes through main pipeline 2, vertical telescoping tube 3 and horizontal branch pipe road 4 and the regional area of plant canopy is lowered the temperature, particularly the regional area such as growing point and spica is lowered the temperature, and the normal growth being beneficial to these organs is grown.During cooling, height according to crop drives horizontal branch pipe road 4 to lift at vertical direction by jacking system, horizontal branch pipe road 4 15cm to 20cm above plant canopy, regulates the level height in horizontal branch pipe road 4, keeps best cooling-down effect with the height change of the growing point of crop.After cooldown period terminates, described vertical telescoping tube 3, horizontal branch pipe road 4 and back(ing) bar 5 are pulled down preservation, has both been avoided that the working place taking in heliogreenhouse, the service life of heliogreenhouse local cooling system can be extended again.Next time reinstalls when using again.

Claims (9)

1. a heliogreenhouse local cooling system, it is characterised in that include air-cooler, pipe-line system and jacking system；Air-cooler is arranged on outside the rear wall of heliogreenhouse, arranges pipe-line system and jacking system in heliogreenhouse；The main pipeline of pipe-line system is connected with the air outlet of air-cooler, and some horizontal branch pipe roads of pipe-line system are connected with main pipeline by vertical telescoping tube；Jacking system drives horizontal branch pipe road to lift at vertical direction；

Described main pipeline is variable cross-section rectangular air duct, makes to have in horizontal branch pipe road identical pressure and flow；Described horizontal branch pipe road is equidistantly distributed in the 15-20cm place, top of heliogreenhouse plant canopy, the first-class spacing in horizontal branch pipe road offers air port, described air port is non-isometrical circular hole, wherein No. 1 air port area of end, horizontal branch pipe road is minimum, No. n-th air port area of conduit entrance place is maximum, to realize the air quantity balanced ventilations such as each air port.

2. a kind of heliogreenhouse local cooling system according to claim 1, it is characterised in that described main pipeline hard PVC sheet material is spliced.

3. a kind of heliogreenhouse local cooling system according to claim 1, it is characterised in that described vertical telescoping tube comprises film tube and the collar；Outer surface at film tube equidistantly fixes iron hoop, it is achieved stretching of vertical direction.

4. a kind of heliogreenhouse local cooling system according to claim 1, it is characterized in that, described horizontal branch pipe road is transparent plastic film pipe, Shang Ge air port perforate poor direction in horizontal branch pipe road faces toward plant, Shang Ge air port, horizontal branch pipe road becomes 60 degree of angles with perpendicular, is distributed along both sides, axis indention.

5. a kind of heliogreenhouse local cooling system according to claim 1, it is characterised in that described air-cooler is wet curtain air-cooler.

6. a kind of heliogreenhouse local cooling system according to claim 1, it is characterised in that described jacking system comprises back(ing) bar, pull rope, support axle, rotates axle and reducing motor；Back(ing) bar and described horizontal branch pipe road are fixed；One end of pull rope connects back(ing) bar, and the other end is walked around support axle and is wound around on the rotating shaft；Reducing motor drives and rotates axle rotation；Described back(ing) bar is aluminum alloy square tube.

7. a kind of heliogreenhouse local cooling system according to claim 6, it is characterised in that two described pull ropes are connected with the two ends of back(ing) bar respectively, and the other end of two pull ropes is all walked around respective support axle and is wound around on the rotating shaft.

8. based on the greenhouse cooling method of heliogreenhouse local cooling system described in claim 1, it is characterised in that when gravity-flow ventilation can not maintain ambient temperature suitable in heliogreenhouse, install air-cooler and each pipeline；Open cold blower fan, air-cooler the cold wind produced sequentially passes through main pipeline, vertical telescoping tube and horizontal branch pipe road and the regional area of plant canopy is lowered the temperature；During cooling, horizontal branch pipe road is driven to lift at vertical direction according to the height of crop by jacking system, horizontal branch pipe road 15cm to 20cm above plant canopy, the level height in horizontal branch pipe road is regulated with the height change of the growing point of crop；After cooldown period terminates, described vertical telescoping tube, horizontal branch pipe road and back(ing) bar are pulled down preservation.

9. greenhouse cooling method according to claim 8, it is characterised in that the growing point of plant and the regional area of spica are lowered the temperature by the cold wind that air-cooler produces.