Specialists from the Polytechnic University of Baja California (UPBC) created a system to heat greenhouses by means of geothermal energy, which is obtained from the heat of the subsoil, because the temperatures in summer and winter in places like Mexicali are extreme in summer and winter.
One of the advantages of the system, which was tested at the university, is that the plants remain at the same temperature throughout the day, which helps decrease the crop's growing period by 50 percent.
The plants and fruits grew more than in an unheated greenhouse and the project offers a level 4 performance coefficient, that is, for each inverted electric kilowatt four thermal kilowatts are produced.
Abelardo Mercado Herrera, a researcher form UPBC and technical manager of the project said that, to develop the system, they had constructed a prototype of a greenhouse that was similar to a commercial greenhouse.
The greenhouse's size was 1,100 square meters, 200 square meters of which are heated and are alternated to grow cucumbers and tomatoes.
The benefits of maintaining temperature in crops that alternate between tomato and cucumber are: productivity rose by 40 percent, plants grew 1.5 meters higher, fruit yields were 30 to 40 percent higher, and also the fruit's weight increased.
The most important thing was that the plant's development period to obtain a harvest decreased from 90 to 45 days.
This closed system is comparable to the radiator of a car, the researcher said. Once it is supplied with water it is no longer necessary to extract it or supply it with more. It circulates and operates with electrical energy, an investment that is recovered and multiplied with the production of geothermal energy.