Abstract
A zone cooling system was tested to modify the greenhouse microclimate for plant growing with the minimum energy input during hot weather. The cooling system was equipped with perforated polyethylene tubes to distribute cool air from spot coolers into the zone in which spinach plants were grown in pots in a plastic greenhouse during the summer of 1991. The ratio of the cooling capacity of the spot coolers to the floor area of the cooled zone in the greenhouse was 0.18 kW⋅ m-2. The cooling system was turned on when one of the air temperature sensors at four positions in the plant zone exceeded 30°C and turned off when all the air temperature data at these positions decreased to 27°C. The overall transmissivity of greenhouse cover and shading materials to solar radiation was 0.54. Watering was done to meet the requirements of the spinach plants. The microclimate conditions in the cooled zone were compared with that in a naturally ventilated zone in a similar greenhouse.During sunny days throughout the experimental period when the daily solar radiation exceeded 18 M J⋅m-2⋅day-1, we were able to maintain the daily maximum air temperature in the plant zone from 30.4 to 36.8°C compared to from 32.0 to 39.0°C in the naturally ventilated plant zone. During the above experimental days, the electrical energy required to run the system was 0.57 to 0.68 M J⋅m-2⋅day-1, and the daily total cooling time was 8.2 to 9.5 hr⋅day-1. Under these conditions, the daily degree-hour value in the cooled plant zone was 22 to 2 7°C⋅hr⋅day-1 lower than that in the naturally ventilated plant zone. The growth of spinach plants in both cooled and naturally ventilated zones showed that the fresh weight of the top part of the spinach plants in the cooled zone exceeded twice that of the naturally ventilated environment on the 45th day after sowing.
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Claims 5
Claim · model-written summary
The cooled zone kept the daily maximum air temperature at 30.4 to 36.8°C, compared with 32.0 to 39.0°C in the naturally ventilated zone.
- Taxon
- spinach
Spinacia oleraceae1 - Treatment
- zone cooling systeme0
- Outcome
- daily maximum air temperaturee2
- Direction
- lowerinferrede2
- Value
- 30.4 to 36.8°Ce2
- Comparator
- naturally ventilated plant zonee2
- Setting
- plastic greenhousee1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A zone cooling system was tested to modify the greenhouse microclimate”
e1“spinach plants were grown in pots in a plastic greenhouse during the summer of 1991”
e2“we were able to maintain the daily maximum air temperature in the plant zone from 30.4 to 36.8°C compared to from 32.0 to 39.0°C in the naturally ventilated plant zone”
Claim · model-written summary
The daily degree-hour value in the cooled zone was 22 to 27 °C·hr·day-1 lower than in the naturally ventilated zone.
- Taxon
- spinachSpinacia oleraceae1
- Treatment
- zone cooling systeme0
- Outcome
- daily degree-hour valuee5
- Direction
- lowere5
- Value
- 22 to 2 7°C⋅hr⋅day-1e5
- Comparator
- naturally ventilated plant zonee5
- Setting
- plastic greenhousee1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A zone cooling system was tested to modify the greenhouse microclimate”
e1“spinach plants were grown in pots in a plastic greenhouse during the summer of 1991”
e5“the daily degree-hour value in the cooled plant zone was 22 to 2 7°C⋅hr⋅day-1 lower than that in the naturally ventilated plant zone”
Claim · model-written summary
The electrical energy required to run the zone cooling system was 0.57 to 0.68 MJ m-2 day-1.
- Taxon
- spinachSpinacia oleraceae1
- Outcome
- electrical energy required to run the systeme3
- Value
- 0.57 to 0.68 M J⋅m-2⋅day-1e3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“spinach plants were grown in pots in a plastic greenhouse during the summer of 1991”
e3“the electrical energy required to run the system was 0.57 to 0.68 M J⋅m-2⋅day-1”
Claim · model-written summary
The daily total cooling time of the system was 8.2 to 9.5 hr day-1.
- Taxon
- spinachSpinacia oleraceae1
- Outcome
- daily total cooling timee4
- Value
- 8.2 to 9.5 hr⋅day-1e4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“spinach plants were grown in pots in a plastic greenhouse during the summer of 1991”
e4“the daily total cooling time was 8.2 to 9.5 hr⋅day-1”
Claim · model-written summary
Spinach top fresh weight in the cooled zone exceeded twice that of the naturally ventilated environment on day 45 after sowing.
- Taxon
- spinachSpinacia oleraceae6
- Treatment
- zone cooling systeme0
- Outcome
- fresh weight of the top part of the spinach plantse6
- Direction
- exceedede6
- Value
- twicee6
- Qualifier
- on the 45th day after sowinge6
- Comparator
- naturally ventilated environmente6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A zone cooling system was tested to modify the greenhouse microclimate”
e6“the fresh weight of the top part of the spinach plants in the cooled zone exceeded twice that of the naturally ventilated environment on the 45th day after sowing”
The same questions in other papers
processing · growth · Spinacia oleracea (spinach)Positive and negative results
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- negative
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2 papers in the same direction as this paper
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Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.