https://etalpykla.vilniustech.lt/handle/123456789/153865 Sat, 04 Apr 2026 12:04:12 GMT 2026-04-04T12:04:12Z http://etalpykla.vilniustech.lt:8080/bitstream/id/a794c5e7-8bab-468c-91a3-ecf02fffbff3/ https://etalpykla.vilniustech.lt/handle/123456789/153865 https://etalpykla.vilniustech.lt/handle/123456789/153931 The use of a genetic algorithm to determine the optimal operating conditions for a low-temperature ORC system Grzebielec, Andrzej; Szelągowski, Adam; Łapka, Piotr; Cieślikiewicz, Łukasz; Seredyński, Mirosław Organic Rankine Cycle (ORC) devices are systems that implement the basic Rankine cycle, but use an organic medium instead of water. These devices can use low-temperature heat, but it should be remembered that the achievable efficiency decreases as the source temperature decreases. Previous publications have shown that maximizing capacity, rather than efficiency, is the main goal of the ORC system. This can be achieved by establishing the correct operating conditions, while ensuring the correct mass flow of the working medium to each component. For instance, the expander must reach the required rotational speed. This work focuses on using genetic algorithms to determine optimal operating conditions and maximize capacity. A genetic algorithm was developed for a newly built ORC device, enabling determination of optimal operating conditions. The results were implemented in the device driver and validated experimentally, confirming that genetic algorithms can easily achieve the desired effect. Sun, 01 Jan 2023 00:00:00 GMT https://etalpykla.vilniustech.lt/handle/123456789/153931 2023-01-01T00:00:00Z https://etalpykla.vilniustech.lt/handle/123456789/153930 Passive house design aspects and analysis in Lithuania Adomaitis, Rimvydas; Valančius, Kęstutis The article provides an analysis of the environment for the development of energy-efficient single-family dwellings in Lithuania in the context of European Union (EU) requirements, Lithuanian (LT) regulations, and climate change trends. It examines the role of Lithuanian architects and builders and the arsenal of tools and challenges in developing energy-efficient houses. The principles and best practices of the German Passive House Institute for Passive House development, their application in Lithuanian climate conditions, specific Passive Houses built in Lithuania, and their operational results are analyzed. The relevance of monitoring in validating the digital building model’s energy efficiency and comfort results as a critical tool for energy-efficient design and of the built houses from assessed. This paper aims to review the regulatory environment for architects working on energy-efficient homes and identify the main objective factors that make this process difficult in Lithuania. In this article we also aimed to provide an overview of the Passive House certification system as a third-party certification system for energy efficient buildings, its evolution, and the place of Passive House in the context of energy efficient buildings in Lithuania. The study shows that although the situation is improving, several obstacles have a significant impact on holding back the process of developing energy-efficient homes, and their solution requires systematic work and much time, which creates a reasonable risk of not meeting the EU and LT energy efficiency targets for buildings in time. We can also see that Passive Houses, built more than a decade ago, are still topping the list of energy-efficient houses in Lithuania today, thanks to their uncompromising rating system. Sun, 01 Jan 2023 00:00:00 GMT https://etalpykla.vilniustech.lt/handle/123456789/153930 2023-01-01T00:00:00Z https://etalpykla.vilniustech.lt/handle/123456789/153929 Analysis of energy demand by a 24-hour store Rusowicz, Artur The paper presents the balance of electricity consumption and fuel oil consumption of a medium-sized 24-hour store. Measurements of the electricity consumption of the various components of the balance were made for air conditioning, refrigeration, fast food, and especially for indoor and outdoor lighting. Their shares over the 12-month period of measurements were determined. Opportunities to reduce electricity consumption by changing the type of lighting of the facility were identified. Replacement of lighting reduced electricity consumption by 38535.8 kWh, which represented a total reduction of 21.2% in the store’s annual electricity consumption. Sun, 01 Jan 2023 00:00:00 GMT https://etalpykla.vilniustech.lt/handle/123456789/153929 2023-01-01T00:00:00Z https://etalpykla.vilniustech.lt/handle/123456789/153928 Carbon footprints of large compression chillers for district cooling – accounting for temporal resolution of the electricity supply Weber, Rosa; Rixrath, Doris; Schauer, Raphael; Krail, Jürgen; Piringer, Gerhard Compression chillers are a common technology used in district cooling networks, with fluctuating cooling loads and consuming different electricity mixes at different times. This work aims to study these effects on the CFs of operating three compression chillers in a district cooling plant in Austria, using LCA-based CF modelling. Electricity consumption dominates the chillers’ CFs. While using the annual average electricity mix overestimated the CF for two warm-season and mixed-season chillers by 12% and 1%, respectively, it underestimated the CF for a mainly cold season chiller by 6%. Seasonal changes in electricity mixes and cooling loads were well suited to explain the calculated CF deviations and should be accounted for in carbon footprints dominated by renewables-rich electricity consumption. Sun, 01 Jan 2023 00:00:00 GMT https://etalpykla.vilniustech.lt/handle/123456789/153928 2023-01-01T00:00:00Z