The walls in architecture determine the energy behavior of a home, the physical and thermal properties of the building elements are capable of controlling the energy transfer of to the interior, avoiding dependence on artificial cooling systems, which increase energy consumption. The research takes advantage of the physical-thermal attributes of straw, considering its use as a material, presenting sustainable constructive solutions for the walls configuration in rural houses with a warm tropical climate. The proposed design starts from identifying the properties of materials with a low carbon footprint such as straw, wood, cardboard, which are viable due to their low weight and easy obtaining. The result is the modular design of the EcoStraw panel that consists of a compressed straw matrix, embedded in a module whose function is to isolate the heat conduction between the interior and exterior, a modular and wooden support structure with the aim of giving structural stability in the stack and a cardboard laminate lining that acts as an interior closing surface. The constructive solution can be industrialized, economical and with a low impact on the environment.

Understanding the physical and thermal material properties is important, due to it helps to determine the thermal comfort and how green is an architectural space, decreasing the energy consumption and avoiding the use of artificial cooling systems. This research is based on three stages: the design, simulations, and analysis of the results. The first stage developed three modules made of straw as a core material, wood and cardboard reinforcement. Successively, the thermal analysis simulation of the modules was carried out using the software ANSYS to determine each one thermal performance under extreme solar radiation of San Jose de Cucuta, Colombia. Thus, obtaining the temperature distribution exterior-interior and the heat fluxes for each typology. The results of the simulation show better thermal benefit in one specific module compared to the others, demonstrating that the implementation of an air chamber is the best strategy to reduce heat transfer in the design of the module, encouraging the use of straw as a constructive system. This research promotes the development of widely viable innovative sustainable construction solutions to configure any type of architectural enclosure in rural areas surrounding the city.