This project will demonstrate a novel way for increasing the energy absorption and storage capacity of passive solar heating systems in green houses. The system uses low-cost polyethylene tubes filled with water laid between the rows of plants that absorb solar energy during the day and release it gradually during nighttime resulting in reduced CO2 emissions due to reduced use of fossil fuels for heating as well as earlier and bigger production of cultivated plants. Activities consist in training farmers on the use of this technology, establishment of field demonstration sites and monitoring of the effects of the passive solar heating in indoor environments. The project foresees organization of Open Days for the public. The data collected and the results of the project will be promoted through a publication.