Heating the root can significantly affect the quality and growth of the crop as well as reducing fuel consumption in the greenhouse. Therefore, one of the most important needs of greenhouses in the cold season is the heating system. In the present research, a combined Root-Zone system with the help of solar heating for the greenhouse was investigated theoretically. The desired system has a linear Fresnel concentrator that supplies the heat needed to bring the root to a temperature of 26 degrees during the day. Considering the risk of running out of fossil fuels in the near future and increasing problems caused by environmental pollution, it is recommended to use renewable energy for heating the greenhouse. The details related to the experimental method of the investigated system in Shahrekord (orbit of 32° latitude and 51° longitude) are as follows. The cloud coefficient factor is considered to be 0.3 for semi-cloudy days and days with low amounts of sunlight. In particular, the light loss in a small Fresnel reflector is higher in the winter period and the solar radiation potential is lower in this period. Useful energy is stored in the hot water tank and then used to heat the roots of the plants. The results show that the diameter and pitch of the pipes, the area of each section is effective on the amount of heat supplied from the collector side, in other words, with the increase in the diameter and pitch of the pipes, the required heat of the system increases.