Effects of Duct-type Pad and Fan on Temperature Reduction andEustoma Quality II

Flower Cultivation Course: Tsuda Maria(Instructor: Usuda Hiromichi)
1. Introduction
A duct-type pad and fan (hereinafter referred to as "duct-type P&F") was introduced lastyear as a heat control measure in the No. 9 greenhouse at the International Academy ofHorticulture, and Mr. Watanabe of the Flower Cultivation Course demonstrated its effect ontemperature reduction and the quality of Eustoma.
However, the humidity inside the duct-type P&F equipment did not rise sufficiently, andthe cooling effect of the ducted P&F was not fully achieved, leaving the quality improvementof Eustoma and soil disease control as issues to be addressed.
2. Purpose of Study
This year, additional tests were conducted to address theremaining

issuesfromthepreviousyear:(1) improving cooling efficiency, (2) improving thequality of Eustoma, and (3) soil disease control.
3. Method of Study(1) Duct-type P&F System and Improvements

冷風As shown in Figure 1, the duct-type P&F system
cools the outdoor air by passing through a moistened cooling
pad, and then the air is sent by a fan through the duct to

図-1 ダクト式 P&F の仕組み図

cool the plants. At this time, one more 10cm thick cooling
pad was added to improve cooling efficiency.
(2) Installation of Isolated Beds
The isolated beds were used to prevent the outbreak of
a wilt disease caused by Fusarium fungi, a soil disease
that caused problems last year.
(3) Method of Temperature Reduction Effect Study
For the temperature reduction effect study, as shown inFigure-2, thermometers were installed in the outdoor
airspace, inside the P&F equipment, in the test area,comparison area on May 18, 2023, and temperaturetransitions

wereinvestigated. Inaddition,humidity

図-2 試験区及び対照区の設 置

transitions were also investigated in the outdoor air and inside the P&F equipment.

(4) Method of Eustoma harvest survey
Fifteen plants each of Bolero Blue Flash, Amber Double Mint, and Bolero Green shown in
Figure-2 were investigated for height, weight, and number of flowers (number of blooming
flowers and bud) at the time of harvest in the test and comparison areas.
4. Results and Observations(1) Result of Temperature Reduction Effect Survey
The temperature reduction effect study is as shown in Figure-3. At 14:20, when theoutdoor temperature was at its highest on this day, the outdoor temperature was 36.0℃, thetemperature inside the P&F equipment was 30.5℃ , and the humidity was 48.1% in theoutdoor air and 71.1% within the P&F equipment, resulting in a -5.5℃ temperature and+23.0% humidity within the P&F equipment compared to the outdoor air.
In addition. last year’s result that thetemperature within the P&F equipment
was -2.5 ℃and the humidity was+14.0% compared to the outdoor airshows

thedoublingofcoolpads

increased the humidity within the P&F
equipment and improved the coolingefficiency.
However, we received advice fromProfessor Shimazu of Gifu University's

図-3 晴天高温時（7 月 6 日 ）の温度・湿度推移

Faculty of Applied Biological Sciences that the cooling effect could be further enhanced byfurther increasing the sealing rate of the P&F equipment.
Comparison of the maximum temperature transition from June 27 to July 2 between thetest and comparison areas shows that the test area was -2.4 to -5.4℃ lower than thecomparison area, -3.4 ℃ lower on average, as shown in Figure-4. Since the averagetemperature in the test area was -2.4℃ lower than that in the test area last year, thetemperature reduction effect was improvedby -1.0℃ compared to last year.
(2) Results of Harvest Survey of Eustom
As shown in Tables 1 and 2, the heightof "Bolero Blue Flash" and "Bolero Green"
were

2.7cm

and4.0cm

higher,respectively, in the test area, while "AmberDouble Mint" was 1.8 cm higher in the図-4

6/27～7/2 の試験区 と対照区の最高温度推移

comparison area.
The weight of "Amber Double Mint" and "Bolero Green" were 1.3 g and 3.2 g heavier,respectively, in the test area, and "Bolero Blue Flash" was 2.8 g heavier in the comparisonarea.
The number of flowers was 0.5 more for

表-1 ユーストマの収穫調査 結果（草丈・重さ）"Bolero Blue Flash," 0.8 more for "Bolero Green"in the test area, while the "Amber Double Mint"
had 0.5 more flowers in the comparison area.
Thus, the harvest survey results showed nosignificant differences between the test andcomparison areas. This is thought to be the result

表-2 ユーストマの収穫調査 結果（輪数）of reduced water irrigation this year to prevent tip
burn and softening of the flower stalks, as theisolated beds made it easier to control the amountof water irrigation.
(3) Effect of isolated beds
As for the installation of isolated beds, lastyear, approximately 30% of the plants died from wilt disease due to soil-borne diseases,
but this year, none of the 90 surveyed plants died.
(4) Future Issues
From this survey, the following issues remain to be addressed: (1) Improvement of P&F
equipment sealing ratio (2) Review of water irrigation methods to improve quality. I would
like to increase the cooling effect of P&F equipment by improving these issues, which willlead to the enhancement of the quality of Eustoma.

Translation of Figures and Tables
図-1 ダクト式 P&F の仕組み図
Figure-1 Duct-type P&F System
冷風Cool Air
有圧ファン
Pressurized Fan
外気を気化冷却
Evaporative Cooling of Outdoor Air
パッド 2 枚2 Pads
外気Outdoor Air
循環
Circulation
水Water
ミラコーラル‘Mira Coral’
ボレロブルーフラッシュ‘Bolero Blue Flash’
アンバーダブルミント‘Amber Double Mint’
ボレログリーン‘Bolero Green’
図-2 試験区及び対照区の設置
Figure-2 Installation of Test and Comparison Areas①外気（通風式）
Outdoor Air (ventilated)②P＆Ｆ装置内（通風式）
Within the P&F Equipment (ventilated)③試験区
Test Area④対照区
Comparison Area
10 列×6 条＝60 株
10 Rows x 6 Strips = 60 Plants
北North南South
パッドアンドファン
Pad and Fan
図-3 晴天高温時（7 月 6 日）の温度・湿度推移
Figure-3 Transition of Temperature and Humidity on Sunny and Hot Days (July 6)
外気温（通風式）
Outdoor Air Temperature (ventilated)
外気湿度
Outdoor Air Humidity
Ｐ＆F 内温度
Temperature within P&F
Ｐ＆Ｆ装置内湿度
Humidity within P&F Equipment
図-4

6 月 27 日～7 月 2 日の試験区と対照区の最高温度推移

Figure-4 Transition of Maximum Temperature in the Test and Comparison Areas from June
27th to July 2nd
表-1 ユーストマの収穫調査結果（草丈・重さ）
Table-1 Eustoma Harvest Survey Results (grass height and weight)
品種
Variety
試験区
Test Area
対照区
Comparison Area
差Difference
表-2 ユーストマの収穫調査結果（輪数）Table-2 Eustoma Harvest Survey Results (number of flowers)
花Flower蕾
Bud合計
Total

合計の差
Total Difference