TECHNICAL REPORT OF SEMI-CLOSED GREENHOUSE ENERGY SYSTEM

General description of the system

The proposed system aims at covering a multitude of greenhouse needs, both during the wintertime and the summertime. The goal is to maintain the most optimal possible conditions inside a greenhouse, so as to maximize production and to extent the farming season. The system requires the construction of a chamber that is an extension of the greenhouse, as seen in Figure 1. The basic construction elements of the chamber are:

A)The basic frame

B)External window with wet panel

C)Internal window between the chamber and the greenhouse

D)Dehumidification surface

The dynamic – functional elements of the system are mentioned separately in every function bellow.

Functions

  1. The system functions examined are:
    1. Ventilation in combination with the already existing roof openings
    2. Cooling with the assistance of the wet panel system and forced circulation
    3. Dehumidification of the greenhouse air through water vapor condensation
      Heating by hot air distribution in the area as a supplementary mode

Cooling function

Cooling is achieved with the help of forced air circulation through the fans and the activation of the wet panel system with the opening of the outer window, as exhibited in Figure 3..

Dehumidification function

The climate formation functions (heating, cooling, and ventilation) and also the crop itself (plant transpiration phenomenon and vaporization) can lead to relevant humidity rise in the greenhouse. With a simple construction, an array of pipes mounted on a steel plate and through which pipes water is circulated from outdoors water tanks, the condensation of water vapor on the pipes’ exterior is possible. In Figure 4, this operation is summarily shown.

Heating function

The construction of the extra chamber and the mentioned equipment (fans, perforated air duct, etc.) enables the inexpensive forming of a heating system that can function complementary to the already existing system. The depiction of the operating principle is shown in Figure 5.

Comparison of greenhouse temperatures

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