Solar Greenhouse - The Active And The Passive Solar Greenhouse

The principle of a solar greenhouse design is to collect solar energy and trap it within the greenhouse and the other storage system that the greenhouse is equipped with. The heat that it is collected is stored for use during evenings and periods when the temperature is colder. Solar green houses could be adapted for most greenhouse designs like the pit, the hoop, the shed type etc. It could also be used in attached greenhouses.

There are two kinds of solar greenhouses, the active greenhouse, and the passive greenhouse design.

The Active Solar Greenhouse

Generally, active solar greenhouses are freestanding greenhouses aimed at commercial production where solar energy is used as supplemental source of heating. To make the solar greenhouse collect optimum power, the length of the greenhouse is oriented along east to west axis. The south sidewall of the greenhouse is glazed to collect and store the most heat while the north-facing wall is insulated or painted with a reflective material to prevent the escape of the heat collected. The west- east orientation could be changed to some degree as different localities could receive small degrees of variances in its orientation to the sun. Nonetheless, this construction is typical as orienting one wall to the south enables the greenhouse to receive maximum solar energy exposure.

Active solar greenhouses are designed to get the most heat especially during cold months. Its angle of glazing is constructed perpendicular to the rays of the sun. Once heat is collected the heat is trapped by the glazing preventing much of the heat from escaping from the greenhouse. Active heating involves the use of thermal storage and subterranean heating within the greenhouse. Pipes are used to force solar heated air, phase change materials, or water buried in the floor for storage and distribution of heat. The system of pipes work by drawing hot air in the roof that is then conducted into the tubing's that are buried in the floor of the greenhouse which is then dispersed throughout the enclosure.

Passive solar Greenhouse

Passive solar greenhouse on the other hand is ideal for use by small growers. Since the passive solar type does not need mechanical pumping and piping systems, the passive greenhouse is cost effective and is easy to maintain. Passive solar heating is collecting and distributing heat through efficient heat storage systems. Heat storage could be done through heat storage vaults or could be done simply through a south facing window that is shaded in the evenings to prevent heat loss.