Experimental Study on Heating a Greenhouse Using Geothermal Energy in Ouargla, Southern Algeria

Abstract

Plant damage and slow growth because of cold during winter are considered the main problems facing greenhouse farming in the Ouargla region, southern Algeria. The possibility of exploiting hot geothermal wells available in the region, from which water flows naturally and has a constant temperature, was considered as a direct and economical option to solve this problem. In this study we tested the use of a heat exchanger inside the greenhouse operating with hot geothermal water in three operating modes: operating one exchanger placed on the surface of the soil, operating one exchanger buried under the surface of the soil at a depth of 40 cm, and operating both exchangers together. We compared each situation with the normal situation in which no heat exchanger is used for heating. The results showed a significant improvement in the thermal climate inside the greenhouse in the three modes compared to the normal mode, with a clear preference for the mode of operation of the two heat exchangers together, as the air temperature improved by approximately 16 degrees Celsius and the soil temperature improved by 14 degrees Celsius. This study has clear importance in promoting the sustainable development of protected agriculture and the effective use of available natural resources.