The article discusses some aspects of the use of renewable energy sources in the climatic conditions prevailing in most of the territory of Latvia, with relatively low wind speeds and a small number of sunny days a year. The paper gives a brief description of the measurement equipment and technology to determine the parameters of the outer air; the results of the measurements are also analysed. On the basis of the data obtained during the last two years at the meteorological station at the Botanical Garden of the University of Latvia, the energy potential of solar radiation and wind was estimated. The values of the possible and the actual amount of produced energy were determined

The paper discusses problems of energy supply of buildings using renewable sources given the local climatic conditions. The meteorological conditions in Latvia and Riga for last year were analyzed. In paper shows examples of energy efficient buildings allowing that to provide comfort temperature and indoor air quality. The structure and composition of local building materials, providing good thermal insulation are described. The heating systems for test buildings using renewable energy sources were investigated. The assessment of the energy efficiency of the “air-air” and “air-water” heat pumps is studied

Under the conditions of continuous increase in the energy consumption, sharply rising prices of basic energy products (gas, oil, coal), deterioration of environment, etc., it is of vital importance to develop methods and techniques for heat and power generation from renewables. The paper considers the possibility to use a sail-type wind turbine for autonomous power supply in Latvia, taking into account its climatic conditions. The authors discuss the problems of developing a turbine of the type that would operate efficiently at low winds, being primarily designed to supply power to small buildings and farms distant from centralized electricity networks. The authors consider aerodynamic characteristics of such a turbine and the dependence of the thrust moment of its pilot model on the airflow rate at different angles of attack. The pilot model with a changeable blade shape has been tested and shows a good performance.

Background: The formation and modification of the surface of polypropylene fibers provide a versatile material for a variety of applications. Objective: This research examines the production of new materials by pneumatic spraying of a polypropylene melt jet, on the surface of which metal and metal oxide nanoparticles are prepared using the sol-gel technique and photoreduction followed by ultra-high frequency processing. We used the obtained materials to remove Bisphenol A in the photoreactor. Method: Based on an analysis of the obtained values of the numerical characteristics in the spray zone and the physical essence of the criteria under consideration, a mechanism for the destruction of the melt jet from the formation of a fiber-forming system is proposed. Analysis of the degradation of Bisphenol A was carried out by electron spectroscopy and fluorescence. Results: A composite active layer, “polymer – inorganic nanoparticles”, on the surface of polypropylene fibers has been demonstrated to create new photocatalytic materials. Bisphenol A in water was examined as a toxicant. Conclusion: Based on the analysis of the obtained values of the numerical characteristics in the spray zone and the physical essence of the considered criteria, it was found that the pressure drop in the nozzle, the nozzle critical section area, and the rheological properties of the melt are dominating factors in the influence on the morphology and size of the ultra-fine fibers obtained by pneumatic spraying. It was determined that materials based on a polypropylene carrier with the largest diameter of 6.71 μm have the best sorption capacity for Bisphenol A. A decrease in the concentration of bisphenol A in water by more than two times in 30 minutes of UV irradiation in the presence of polypropylene was achieved without additional injection of oxidants.

The article considers some aspects of solving the urgent problem related to waste processing, in particular, renewable biowaste from the food industry. Development and implementation of modern technologies for processing and recycling various organic waste will reduce dependence on fossil energy sources, achieve carbon neutrality and maintain environmental safety. The object of the study is organic waste of the agro-industrial complex in the form of bone mass. The possibilities of efficient extraction of the valuable component using electro-hydro-pulse processing were experimentally studied. A description of the basic diagram of the electro-hydro-pulse installation and testing methods for different processing modes are given. Optimum values ​​of electrical parameters are determined, allowing to increase the degree of extraction of valuable components from organic raw materials while reducing the processing time.