There are two ways to ventilate greenhouses: manual and automatic. Automatic ventilation of the greenhouse can be hydraulic, electric, bimetallic or in the form of a vents-machine.
Benefits of automatic greenhouse ventilation
Many greenhouse owners are not constantly on their plots, so they cannot organize manual ventilation. In this case, it is more convenient to install automatic ventilation of the greenhouse.
The electrical ventilation system is easy to install and maintain: only a thermostat and a fan are needed. The relay is set to the temperature at which the fan should start. Such fans can be placed as many as you like throughout the greenhouse structure. There are relays that regulate the intensity of the air stream. The disadvantage of this greenhouse ventilation system is that the vents are opened with complex and not cheap mechanisms. In addition, a constant source of electricity is required. The easiest way out of the situation is solar panels.
Hydraulic ventilation system
Hydraulic ventilation in the greenhouse is widely used. A simple design that works for a long time without breakdowns consists of levers that open the vents.
The water in the system heats up, its volume increases, the lever rises and opens the transom. As soon as the water cools down, the window is closed. A water tank is installed in the greenhouse, which acts as a "thermometer". Another tank is installed on the street, which is connected with pipes to the internal one according to the principle of communicating tanks. Due to the presence of an external tank, the pressure in the system rises gradually, the vent opens slowly.
The disadvantage of the system is too slow heating and cooling of water, which complicates the calculation of greenhouse ventilation. The air temperature outside will drop much faster than it will "reach" the mechanism. And delicate plants can die.
Bimetal ventilation
The operation of this greenhouse ventilation system is based on the expansion of the metal when heated. The movement is made of two different metals with different characteristics. Therefore, as the temperature rises, one metal plate bends and opens the window. The second closes during cooling. It is a very inexpensive system that is easy to install. But its disadvantage is that the power of the plate may not be enough if the window area is large. And it can be difficult to make an accurate calculation of greenhouse ventilation at certain temperatures.
