What is the primary purpose of ventilation in greenhouses?
B
Reduce irrigation needs
C
Regulate temperature and humidity
D
Increase soil nutrients
Analysis & Theory
Ventilation regulates temperature, humidity, and gas exchange within the greenhouse environment.
Which of the following is a characteristic of **natural ventilation**?
C
Relies on wind and thermal buoyancy
D
Controlled by thermostat
Analysis & Theory
Natural ventilation works by wind pressure and warm air rising (buoyancy), requiring no mechanical input.
What component is essential for **natural ventilation** in a greenhouse?
Analysis & Theory
Side and roof vents allow air movement, facilitating natural ventilation by convection.
Which of the following describes **forced ventilation**?
B
Operates through passive airflow
C
Uses mechanical devices like fans
D
Relies only on temperature difference
Analysis & Theory
Forced ventilation uses mechanical systems such as exhaust and circulation fans to move air.
A major advantage of forced ventilation over natural ventilation is:
C
More precise environmental control
Analysis & Theory
Forced ventilation offers better and more consistent control of internal climate regardless of external conditions.
Which factor does **not significantly affect natural ventilation efficiency**?
B
Air temperature difference
D
Size and position of vents
Analysis & Theory
Fan speed is relevant to forced ventilation, not natural ventilation.
What is the function of **circulation fans** in a forced ventilation system?
C
Ensure uniform temperature and humidity
Analysis & Theory
Circulation fans mix air to prevent hot or cold spots and maintain uniform conditions.
Which of the following is **a limitation of natural ventilation**?
C
Less effective in still weather
D
Requires frequent maintenance
Analysis & Theory
Natural ventilation depends on external wind and thermal gradients, making it ineffective in calm weather.
In which condition is **forced ventilation** preferred over natural ventilation?
B
Remote areas with no electricity
C
Large commercial greenhouses
Analysis & Theory
Forced ventilation provides consistent airflow and is essential for large-scale commercial greenhouses.
How can energy use in **forced ventilation** be optimized?
A
Operate fans continuously
C
Install thermostats and humidity sensors
D
Keep vents open all the time
Analysis & Theory
Using sensors and thermostats allows fans to operate only when needed, saving energy and maintaining ideal conditions.