Air Conditioning of a Greenhouse
The first step in heat ventilation and air conditioning a greenhouse is to install proper vents. Proper ventilation will prevent excessive heat loss. You should adjust greenhouse vents before heating season starts, so that they are not poorly sealed. To reduce heat loss during the winter, install fan systems, which draw in cool outside air and exhaust heated air. These systems are effective for greenhouses that are not tall, but have a high ceiling.
Another factor in greenhouse heat loss is air infiltration. In old greenhouse air conditioner may be able to penetrate through cracks and holes. The same holds true for fiberglass or glazing sheets that are too large. A single or double layer of rigid or flexible plastic will reduce this problem. The orientation of a greenhouse should be such that it receives the sun’s rays as much as possible, but also allows for shade.
Proper ventilation also allows fresh air to enter the greenhouse. Proper ventilation can prevent excessive heat and keep plants healthy. Without adequate ventilation, the temperature inside the greenhouse may reach 100 degrees Fahrenheit or higher. This will cause stress on the plants and reduce growth. Proper ventilation should be checked regularly, since excessive heat can lead to a reduced quality of the plants. If you have an unventilated greenhouse, install ventilation fans near plants that are vulnerable to pests and disease.
Heat Ventilation and Air Conditioning of a Greenhouse
Fans are an essential component of a greenhouse’s HVAC system. Located above the plant canopy, exhaust fans will help circulate the air in the greenhouse. They should be installed at a height of at least three feet. A properly-sized fan should be able to provide 1/2 cubic foot of air per square foot of floor area. Aside from fans, heat-ventilating greenhouses can also be cooled by air in the greenhouse.
A fog system adds moisture directly to the greenhouse environment and evaporates it when the weather is dry. Another component of greenhouse ventilation is shade. Shade, whitewash, or shade cloth, can reduce the light and temperature inside. Continual positive air movement improves greenhouse conditions, while exhausting humidified air, carbon dioxide, and humidity levels are equalized. This leads to healthier plants and reduced disease problems associated with high humidity.
Good insulation is a vital component of greenhouse ventilation. If the walls are warm, the greenhouse will absorb heat and release it gradually. Adding a bubble wrap to the walls will also help capture warm air during the winter season. Even cooler weather will need good ventilation. You can’t afford to pay for a costly electric heater all winter. However, bubble wrap is a cheap, simple method of insulation.
Evaporative cooling involves the use of mist nozzles. These are designed to spray small drops of water into the air, without wetting plant material. The water evaporates while suspended in the air, cooling the air through evaporation. Water-saturated air is then removed from the greenhouse through roof vents and low-volume fans mounted in the walls. But mist systems are not without drawbacks.
