Preface of VSI: ATE_AESMT’23

The special issue “VSI:ATE_AESMT‘23“ aims to provide novel research papers in the field of the Renewable Energy as a part of the conference “Alternative energy sources, materials and technologies (AESMT’23)”. The conference was held in Sofia, Bulgaria in the time period 16–17 May 2023. Some more important points about the AESMT’23 conference are as follows: - Representatives of 24 countries (Bulgaria, Canada, China, Cuba, Germany, Greece, India, Iraq, Israel, Italy, Kazakhstan, Kosovo, Latvia, Macedonia, Poland, Portugal, Romania, Russia, Serbia, Singapore, Spain, Turkey, Ukraine, United Kingdom) sent their works to the conference; - The total number of the presented articles was 76 (46 of them orally, the others were posters); - After the preliminary review, 16 articles have been selected for submission in “Applied Thermal Engineering” journal.