Vincenc Butala

Vincenc Butala
University of Ljubljana · Faculty of Mechanical Engineering

About

61
Publications
14,732
Reads
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1,495
Citations
Citations since 2016
9 Research Items
1041 Citations
2016201720182019202020212022050100150
2016201720182019202020212022050100150
2016201720182019202020212022050100150
2016201720182019202020212022050100150

Publications

Publications (61)
Article
From a sociological and economic perspective, odour pollution is one of the most complex problems in the field of air quality. Therefore, various approaches and odour impact criteria are particularly relevant when assessing odour exposure in the areas of different land use. The number of odour assessment methods is limited, and the lack of analytic...
Article
The building's balance point temperature represents the outdoor temperature at which no auxiliary energy is needed to ensure thermal comfort. Its estimation presents the main challenge of applying the degree day method for space cooling applications, since in addition to building thermal characteristics it also depends on internal and external heat...
Article
Besides air velocity, turbulence intensity and air temperature there are also other factors, which influence human thermal response to air movement. In this study, the impact of temperature fluctuations in airflow on human thermal sensation and perception of draught was examined. For the purposes of the study an air supply unit was designed for gen...
Article
Using thermal energy storage (TES) in phase change materials (PCMs) can reduce energy consumption in buildings. In summer, cold can be stored at night and released during the daytime therefore reducing the temperature while in winter, the system can be connected to a solar air collector that supplies heat. This article presents a paraffin based the...
Article
Heating of ventilation air accounts for a significant part of energy consumption in buildings. The paper presents the use of latent heat thermal energy storage (LHTES) heated with a hot air solar energy collector mounted on the facade of the office building at the Faculty of Mechanical Engineering in Ljubljana where experiments have been carried ou...
Article
Actual national and international energy strategies generally encourage the use of renewable energy sources. Thermal energy storage (TES) offers various opportunities in the design of renewable energy systems. Thermochemical heat storage has gained popularity among researches because of higher energy density and lower heat loss compared to sensible...
Article
In the present paper improvement of the air solar collector ventilation system with latent heat storage (LHS) for the heating period is presented. LHS in phase change materials (PCM) improves effectiveness of the ventilation system and resolves mismatch between obtained heat from the air solar collector and its use for ventilation of the office. Ap...
Article
Numerous metrics and indices have been proposed for the assessment of thermal perception and comfort. Commonly used indices based on the estimate of the heat flow between the human and its environment includes the well-known Fanger’s method, also known as the PMV-PPD thermal comfort model. Recently this thermodynamic approach has been expanded with...
Conference Paper
Full-text available
Actual national and international energy strategies generally encourage the use of renewable energy sources. Improving the energy performance of buildings is the key to achieve goals of the European Union (EU) 2030 Energy Strategy, which is to reduce greenhouse gas (GHG) emissions by at least 30 % compared to 1990 levels, because the buildings are...
Article
Purpose – Bilateral project with Slovenia and Turkey with the title thermal energy storage for efficient utilization of solar energy was the basis for this paper. The paper aims to discuss this issue. Design/methodology/approach – The paper is the review of solar thermal storage technologies with examples of use in Slovenia and Turkey. Findings – T...
Article
In order to reduce energy consumption in buildings, a solution using phase change materials (PCMs) as thermal energy storage (TES) is presented. During summer nights, cold is stored and delivered during the day to reduce cooling load, whereas in winter, heat from solar air collector is stored for heating during morning and evening hours. Proposed i...
Article
Full-text available
Combustion experiments conducted in domestic stove burning hard coal demonstrated a predominant influence of the coal chlorine content on the PCDD/F emissions, together with a pronounced effect of the flue gas temperature. PCDD/F concentrations of over 100 ng TEQ/m(3), three orders of magnitude higher than in a modern waste incinerator, were measur...
Technical Report
Full-text available
This is the final overview report for the Intelligent Energy Europe iSERVcmb Project funded by the European Commission between May 2011 and May 2014
Article
Full-text available
Buildings have negative effects on the environment throughout their life cycle, i.e. from the phase of obtaining raw materials and manufacturing materials and components up to the sale, building and use through the final phase of removal when the building is decommissioned. In general, current legislation limits both the use of energy and the emiss...
Article
Dispersion and flow of air in passenger compartments of vehicles are important to assure a comfortable environment for passengers, driver concentration and safe driving conditions. The article describe numerical adiabatic flow simulations for "mute", an electric car. Air streams in its passenger compartment were simulated; air velocities were compa...
Article
Full-text available
In practice a number of calculation tools are used to calculate annual energy flows in buildings. Their use yields accurate results but requires the input of a large number of parameters in the complex calculation procedures involved. The values of these parameters are usually known only after the planning process of a building has been completed....
Article
Abstract Thermal energy storage (TES) is regarded as among the most feasible environmentally friendly solutions for saving energy. R&D activities for heating and cooling of buildings lead to the development of various technology types. This paper attempts to give an overview of the energy situation, solar energy potential, TES concepts and technolo...
Conference Paper
Full-text available
Energy storage technologies are a strategic and necessary component for the efficient utilization of renewable energy sources and energy conservation. There is a great technical potential to substitute burning of fossil fuels by using stored heat. Phase change material (PCM) is ideal for energy storage purposes since it can store energy at relative...
Poster
Full-text available
Introduction Cough is one of the most dangerous mechanisms for transmission of droplet infections. In order to prevent these infections, it is necessary to properly analyze cough flow dynamics. Previous studies (Gupta et al. [1], Mahajan et al. [2], Singh et al. [3]) dealt with samples, characterized by too many physiological variables and/or inapp...
Article
Detailed information of transient exhaled air dispersion and recirculation in the breathing zone can be obtained using computational fluid dynamics (CFD) to generate detailed numerical models and obtain the necessary information. In this study, interaction of free convection flow around human body with respiration flow of breathing and vertical per...
Article
One of the technologies which help to reduce energy consumption is the thermal energy storage for cooling applications where the cold is stored in phase change materials (PCMs). Such materials would be suitable for use in buildings because they can store a large amount of cold and phase change occurs at a constant temperature, thereby increasing th...
Conference Paper
A lot of research on the topic of energy storage is available, since there are discrepancies between the time when the energy is available and the time when it is needed. One possibility is the latent heat storage. The aim of this study is to determine what the thermal characteristics of the storage unit are and how such a unit could be incorporate...
Article
In this paper an exergy-based correlation between thermal comfort and the thermal environment was investigated. The two-node human thermal model was expanded by applying the 2nd law of thermodynamics in order to calculate the exergy destruction. This value was compared to the standard Predicted Mean Vote (PMV) value and a formal analogy between the...
Article
Full-text available
In cases where a quick insight into the operation of an HVAC system is more important than accuracy, cooling degree days can be used for monitoring electric energy consumption dependent on meteorological conditions. Cooling degree days are calculated from differences between outdoor temperatures above the base temperature and the base temperature i...
Article
The cooling degree days concept is a tool to estimate and analyze weather related energy consumption in buildings, i.e. the cooling system electric energy consumption. The main problem with applying this method is that it disregards latent cooling loads. This paper deals with an approach for monitoring electric energy consumption due to cooling in...
Article
Full-text available
Alternative solutions for cooling and ventilation of buildings have appeared in practice as a counterweight to energy wasting conventional systems. Free cooling principle with phase change material (PCM) has been used as an alternative method of cooling and ventilating buildings which combines night ventilation and increased thermal mass. A simulat...
Article
This paper describes the application of exergy analysis to human heat and mass exchange with the indoor environment. The basis for this paper is the existence of a formal similarity between the parameters defining human heat and mass transfer governed by physiological processes and the parameters defining exergy destruction. Basic heat and mass tra...
Article
This article presents an experimental analysis of cooling buildings using night-time cold accumulation in a phase change material (PCM), otherwise known as the “free-cooling principle”. Studies of the ceiling and floor free-cooling principle, as well as passive cooling, are presented. The free-cooling principle is explained and some of the types of...
Article
This article presents an experimental analysis of cooling buildings using nighttime cold accumulation in a phase change material (PCM), otherwise known as the “free-cooling principle”. Studies of the ceiling and floor free-cooling principle, as well as passive cooling, are presented. The free-cooling principle is explained and some of the types of...
Article
Full-text available
An analysis of the ventilation effectiveness measured on a prototype system for local air-conditioning named PERMICS (Personal Microclimate System) was made based on simultaneous measurements of velocity field and of tracer gas concentration using the decay method. A new parameter based on a relative decrease of tracer gas concentration in the firs...
Article
An analysis of the ventilation effectiveness of a prototype personalized ventilation system of working places named PERMICS-LOS1 (Personal Microclimate System) was made, based on measurements of the air velocity field and of tracer gas concentrations using the decay method. The emphasis of the analysis was mainly on an experimental verification of...
Article
The article presents a short review of electricity production from renewable energy sources in Slovenia. In Introduction the term of "green electricity" is defined. Comparison of structures of electricity production is presented for the years 1990 and 2003. The main part of the article presents an approximate data for technical and theoretical pote...
Article
This article presents a combined heat and power (CHP) unit using wood biomass to provide an energy supply for housing. The Stirling engine is used as a CHP producing technology for which thermodynamic analysis was carried out. The thermodynamic values were mathematically calculated and a computer program for CHP simulation was written. A parametric...
Article
This paper presents a combined heat and power (CHP) unit using wood biomass to provide an energy supply for housing. The Stirling engine is used as a CHP-producing technology for which a thermodynamic analysis was carried out. The thermodynamic values were mathematically calculated and a computer program for the CHP simulation was written. A parame...
Article
People's perception of the thermal environment and the quality of air in mechanically and naturally ventilated office environments is discussed. Interdisciplinary research of the indoor environment (technical and medical fields) was based on the simultaneous measurement of the thermal environment parameters, as well on as on surveying employees dur...
Article
This article presents an experimental and numerical analysis of cooling buildings using night-time cold accumulation in phase change material (PCM), otherwise known as the ‘free-cooling principle’. Experimental and numerical studies of the ceiling and floor free-cooling principle, as well as passive cooling, are presented. The free-cooling principl...
Article
This paper presents an experimental and numerical analysis of building cooling using night-time cold accumulation in phase change material (PCM), otherwise known as the "free-cooling" or "passive-cooling" principle. The phase change materials were used in ceilings and floors. The free-cooling principle is explained and some of the types of PCMs sui...
Article
Ventilation effectiveness was measured on a prototype system for local air-conditioning named personal microclimate system (PERMICS). Based on simultaneous measurements of velocity field and of tracer gas concentration, a new parameter based on the relative decrease of tracer gas in the first minute of system operation was introduced. The usefulnes...
Article
Full-text available
In the current transformation of the air conditioning (AC) market, important efforts should be achieved to improve the energy efficiency of these systems all along their life cycle. To detect and define the performance degradation of these facilities, a global approach has to be developed and the complexity of the systems implies the creation of re...
Article
The performance of a boiler with a built-in thermal storage unit is presented. The thermal storage unit is an insulated water tank that absorbs surplus heat from the boiler. The stored heat in the thermal storage unit makes it possible to heat even when the boiler is not operating, thus increasing the heating efficiency. A system with three compone...
Article
The problems associated with the influence of the heating environment and quality of air on people in an office environment are discussed. The mechanical and natural ventilated buildings are analyzed in light of the hypothesis that the appearance of health conditions associated with sick building syndrome are influenced in a statistically significa...
Article
Heating appliances used in buildings are designed according to building's heating load as a function of outdoor design air temperature. Usually this temperature is quite lower than the average external air temperature during the heating season. For most of the heating season, heating appliances do not operate at their nominal heating capacity. This...
Article
Energy and indoor environmental audits of energy consumption and indoor air quality were taken in 24 school buildings in Slovenia. The audits show that these buildings are high energy consumers and have poor indoor air quality, as expressed by 60% of the surveyed pupils. This article deals with energy consumption in the analysed schools. The nomina...
Article
The gasification rate was measured of chunks of coal with a high content of volatiles, average size of 65 x 47 X 38 mm and an initial weight of 120 +/- 7 g. The influence of air temperature and velocity on the gasification rate was studied in a tubular experimental device. The time dependencies of the gasification rate and some gaseous species on a...
Article
Carbon dioxide (CO2) is a good indicator of the concentration of human bioeffluents in closed space. The use of energy for heating and/or cooling rises with the ventilation noneffectiveness. There is a link between the concentration of pollution overall in the air and the concentration of pollutants in the breathing zone. The consequence of this is...
Article
The paper presents experimental research into the combustion of individual coal pieces with dimensions of 6.5 × 4.7 × 3.8 cm and masses of 120 ± 7 g in a combustion pipe. The coal pieces were burned under known thermodynamic conditions in a convective air current, which served as an oxidant. Based on experimental data obtained from the combustion o...
Article
A complete energy and indoor air quality review of the situation in a number of Slovenian schools was made. A comparative study, using specific indicators, shows large energy requirements and low air quality. Analysing needful steps, in order to improve present situation, we've established intricacy in providing low energy loss and high quality ind...
Article
People today spend 90% of their time in enclosed spaces so that they almost become prisoners of their own civilisation. But we have to allow fresh air into our working and living spaces if we want to feel well and breathe air that is not of deleterious quality. The use of energy for heating and/or cooling rises with the effectiveness of ventilation...
Article
People nowadays spend 90 % of their time in closed spaces, so that they became almost prisoners of their own civilization. But it is necessary to let fresh air into working and dwelling places if we want to feel well and breathe air that is not of a decterious quality. The use of energy for heating and/or cooling rises with the effectiveness of ven...
Article
The Center for Energy and Environment Technologies (CEET) is currently involved in various research projects aimed at developing new products and concepts for the environmental technology industry. Among the various activities being undertaken by the CEET are the development of fuel-oil boilers, wall-hung gas boilers, solar wall TRIMO, anti traffic...
Article
Energy use surveillance gets more and more on importance. The approach to integral energy-use planning and introduction of energy management is crucial. Energy bookkeeping makes the work of energy management for efficient energy-use highly simplified.
Article
In this article we study the problem of wood fuel supply in order to satisfy demand at heating plant with minimal costs and to evaluate environmental impacts, namely energy usage and the accompanying CO 2 emissions. This problem is very complex for a supply manager due to the characteristics of the production, processing and transport of wood fuel....
Article
Full-text available
The main similarity among the human physiology models is the application of energy balance concepts and the use of energy and mass exchange mechanisms. In this paper a different approach is presented, namely an analysis based on 2 nd law of thermodynamics. This approach provides an extended quantitative and qualitative method to characterise the pr...

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Projects

Project (1)
Archived project
Building on the results of its predecessor projects, AUDITAC (2005-2007) and HARMONAC (2007-2010), the iSERVcmb project provides a detailed insight into how energy is used in HVAC systems and buildings through analysis of operational energy use data from HVAC systems around Europe. The project demonstrates significant electrical savings ranging up to 33%, and 9% on average, have been achieved by understanding the details of energy usage and power demands at the level of individual components within buildings. The iSERVcmb project proposes and trials a practical, structured process which can be used across all buildings and HVAC systems in the EU Member States. Part of this approach is the use of benchmarks of energy use and power demands at HVAC component level, partially derived from sub-hourly automatic monitoring data collected from over 2800 HVAC systems across the EU. The iSERVcmb approach uses existing metering and sensors, along with information on buildings assets and activities, such that benchmarks, powerful in diagnostic work, can be derived from that data - and produced for individual building configurations and activities supported.