[ISSN: 2737-8071] 1 Int J Eng & App Phy, Vol. 2, No. 3, September 2022 International Journal of Engineering and Applied Physics (IJEAP) Vol. 2, No. 3, September 2022. ISSN: 2737-8071 Simulation of the mechanical solar ventilation with phase change materials in building envelope with 2 software TRNSYS and DESIGNBUILDER. 1 NOUHAILA BENACHIR , 2 FARIDA BENDRIAA, 3 TAOUFIQ MOUHIB Hassan I First University of Settat, Ecole Nationale des Sciences Appliquées, LISA Laboratory, Berrechid 26100, Morocco. Article Info ABSTRACT Article history: Received Jun 9, 2022 Revised Nov 20, 2022 Accepted Jan 11, 2022 When it comes to building simulation, many applications and programs come to us from all over the world. A multitude of software has been developed for similar purposes by different universities and laboratories. In this section we are concerned only with programs related to: calculation of thermal and electrical load zones, building envelope, solar gains, solar ventilation, renewable energy production, building electrical equipment, HVAC systems and equipment, and economic performance evaluation. These programs also take into account for the most part climatic input data. The use of simulation is decisive in the design process of a new building. It allows the evaluation of different alternatives in terms of energy performance and occupant comfort and is thus an essential decision-making tool. The resulting increase in the precision requirements of the calculations makes it essential to appreciate the uncertainties associated with these forecasts in order to improve the construction and evaluation process. This article presents a comparison between the evaluations of uncertainties based on the results of simulations in the design phase. If the diversity of these programs is a boon in that it allows many different simulations to be compared, it also poses a problem in terms of comparison of results and even choice of program. A major current challenge is therefore to succeed in making these different software programs communicate, many research works have been published in this sense. Keywords: TRNSYS AND DESIGNBUILDER PCM. Performance energetic Dynamic simulation. MSV. This is an open access article under the CC BY license. Corresponding Author: BENACHIR NOUHAILA Hassan First University of Settat, Ecole Nationale des Sciences Appliquées, LISA Laboratory, Berrechid Email: (Benachir.nouha@gmail.com/n.benbachir@uhp.ac.ma/