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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 analytical techniques to determine odour concentration makes odour assessment even more complex. It is essential to analyse the spatial and temporal distribution of odour concentrations in order to assess odour nuisance in the ambient air. Since sampling of odorous air in the field for subsequent determination of odour concentrations in a laboratory by dynamic olfactometry is time-consuming, two approaches are used to assess odour concentrations in ambient air: estimating odour concentration by field inspection and calculation of odour concentrations using atmospheric dispersion models. The latter is the most commonly used technique. Our study aimed to provide fundamentals for an odour regulatory framework in Slovenia. While a multitude of approaches is presently applied to establish odour regulation framework, a broader approach remains lacking. Various odour emission sources were identified to evaluate available methods and techniques to assess odour impact. The impact area was selected to analyse and compare the impact of different odour sources in terms of odour concentration, odour frequency, odour offensiveness, land use, and receptor location. Finally, odour impact criteria were set according to odour offensiveness and concentration, percentile compliance level and land use. [ABSTRACT FROM AUTHOR]

Highlights • Influence of temperature fluctuations was examined in a human subjective experiment. • Generated airflows had distinct cooling effect on subjects. • Study indicates that sensation of draught was influenced by airflow temperature fluctuations. Abstract 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 generating airflows with temperature fluctuations and used in a subjective experiment. The experimental study indicates that temperature fluctuations possibly influence the human perception of air movement with a distinct cooling effect. At high values of frequency and amplitude fluctuations a large discrepancy was found between predicted and measured values of draught discomfort. [ABSTRACT FROM AUTHOR]

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 thermal storage unit and its annual operation. A 2D model is set up in Fluent, thereby calculating the thermal response of the unit. The cooling and heating modes along with a numerical analysis of different parameters are considered and the best ones are determined for the city of Ljubljana. [ABSTRACT FROM AUTHOR]

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 the application of the second law of thermodynamics. In this paper, an exergy-based analysis of the relation between the human and its environment is presented. Heat and mass flow rate due to convection, radiation, evaporation and respiration are calculated and expressed in terms of exergy loss. This value is used in the modified Fanger's thermal comfort model, where the heat balance equation is replaced by the exergy loss. The paper builds upon prior studies on determination of internal and external exergy losses by revised and newly defined formulas taking into account clothing and indoor conditions. The results quantitatively show that thermal energy load in the original Fanger's PMV model could be substituted by exergy loss and it corresponds to a certain level of subjective assessed thermal comfort level. [ABSTRACT FROM AUTHOR]

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 emissions allowed during operation, but does not limit the other parameters that define the design of contemporary sustainable buildings. Determining the sustainability of buildings should take place in the planning phase of the project, when it is still possible to influence the outcome. In this article, a simplified method using five chosen indicators is employed to evaluate the level of sustainability. The areas to be evaluated are energy efficiency, use of primary energy, CO2 emissions, costs, and the level of living comfort achieved. The evaluation using these indicators is carried out using three subjective and objective weighting methods, such that the final evaluation includes the viewpoints of an independent evaluator and the points of view of both the user and the state. In the case of an assessment of the five indicators for new constructions, it is ensured that the designs for the new building in energy class A have the best total result of the assessment and therefore the best sustainable design, regardless of additional energy, environmental and economic Investment during the building phase. With a suitable choice of heat supply, even new buildings in energy class C can come close to the effectiveness of a building design in energy class B. [ABSTRACT FROM AUTHOR]

Highlights: [•] The modelling of a simplified evaluation method for energy flows in new buildings. [•] The quality parameters for the method are identified by the correlation analysis. [•] The method facilitates the evaluation of energy flows by using fewer key parameters. [•] The method can be used with different parameters and different levels of accuracy. [•] The method can be used in the design phase of planning single-family houses. [ABSTRACT FROM AUTHOR]

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 simulation model defining the transient behaviour of the phase change unit was used. The heat transfer problem of the model, which was treated as two-dimensional, was solved numerically by an enthalpy-based finite differences method. The computer program was written in Fortran program language and can calculate temperature fields in certain time in paraffin area, as well as air temperatures. Energy conservation was calculated from meteorological data for a reference year in a specific country. The difference between inlet and outlet temperature were calculated, from which energy conservation for a cooling season were obtained. Calculated energy savings are from 14 to 87% depending on selected parameters. [ABSTRACT FROM AUTHOR]

Abstract: 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 transfer is calculated using a standard two-node human physiological model. To enable an exergy analysis the model was divided according to heat and mass transfer over appropriate boundaries. The exergy analysis was performed for each process with regard to the type of exergy that participates in heat and mass exchange with respect to the indoor environment. The results provide insight into the complex interactions between the human body and environment as characterized by exergy destruction. Furthermore, the analysis indicates that at given physiological parameters only a certain combination of environmental conditions ensures minimal exergy destruction. These environmental and human conditions coincide with expected level of thermal comfort. [ABSTRACT FROM AUTHOR]

Abstract: 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 PCMs suitable for summer cooling are listed. An experiment was conducted using paraffin with a melting point of 22°C as the PCM to store cold during the nighttime and to cool hot air during the daytime in summer. Air temperatures and heat fluxes as a function of time are presented for different air velocities and inlet temperatures. [Copyright &y& Elsevier]

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 principle is explained and some of the types of PCMs suitable for summer cooling are listed. An experiment was conducted using paraffin with a melting point of 22°C as the PCM to store cold during the night-time and to cool hot air during the daytime in summer. Air temperatures and heat fluxes as a function of time and dimensionless cold discharging values are presented for different air velocities. Experimental analysis of one week of measuring under real conditions is presented in order to show how cold storage functions. Copyright © 2007 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Abstract: 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 usefulness of this parameter has been verified by simulation results from commercial computational fluid dynamics (CFD) software. This parameter makes quick measurements of the local efficiency of ventilation systems possible. [Copyright &y& Elsevier]

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 components is described. The model of the system and the mathematical model were made using the TRNSYS program package and a test reference year (TRY). The degree of efficiency, which optimizes the thermal storage volume and the heating power of the boiler, was determined. The thermal storage must also ensure that the heat is stored at the highest possible exergy level, and complete mixing of the water is a condition for optimizing the thermal storage. The matching of the boiler’s heating capacity with the thermal storage unit ensures a supply of heat even when the boiler is not operating. [Copyright &y& Elsevier]

Abstract 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 gains. In this paper, a new approach for determining the instantaneous balance point temperature, based on an optimization-based grey-box modelling procedure, is presented. The developed grey-box model is built on an assumed functional dependency between the building thermal load and the power demand of its HVAC system. Its application requires only the use of basic building geometric parameters apart from the cooling electricity demand and corresponding meteorological data, which are utilized to estimate the model parameters using a derivate-free optimization procedure. Additionally, a new technique for visualizing and analyzing the behavior of the obtained instantaneous balance point temperature is introduced. The proposed methodology is verified on a set of artificially generated data, achieving an average prediction error of 5.2%, and its applicability demonstrated on a sample of real tertiary sector buildings. The results indicate that the presented methodology can be used to deduce building and corresponding HVAC system characteristics. Highlights • An approach for determining the instantaneous balance point temperature is proposed. • The approach is based on an optimization-based grey-box modelling procedure. • The approach is verified on artificial data and tested on data from real buildings. • A visualization technique for analysing the balance point temperature is introduced. [ABSTRACT FROM AUTHOR]

The article reflects on the capacity of engineers to excel in different fields such as material science, thermodynamics, and robotics. He notes how engineers can identify and assess the physical, mechanical, and other root causes of problems to aid derive to policies and engineering solutions. He stresses that the ability to address these challenges benefit from the continuing advances in analytical methods, material science, and computational fluid dynamics of structural engineering.

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 and latent heat storage. On the other side solar energy has been recognized as one of the renewable energy sources with the most potential. This paper reviews thermochemical heat storage technologies and systems with emphasis on systems involving solar energy utilization in buildings. The studies are reviewed based on used storage materials, system configuration as well as models to predict and optimize system performance. [ABSTRACT FROM AUTHOR]

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 itself, therefore containing both climate and building information. The difficulties in applying this method are the determination of base temperature and choosing a procedure for calculating degree days, which vary depending on the resolution of the weather data used. In addition, the cooling degree method has a major flaw, i.e. it considers only a linear dependence between cooling energy consumption and sensible cooling load, thereby ignoring latent loads, which become more significant at higher outdoor temperatures In this article an analysis of real electric energy consumption data using the cooling degree method and an improved method derived from it that includes latent loads, as well as a comparison between them, are shown. Both methods are applied several times to metered data, each time with a different combination of a method for determining base temperature and a degree day calculation technique. [ABSTRACT FROM AUTHOR]

Abstract: 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 buildings based on cooling degree days, which allows an estimation of latent loads. In addition to applying methods for determining base temperature to base humidity, a new technique is introduced, which is based on a significance test of the enthalpy latent days partial regression coefficient. Analogous to the performance line concept, the influence of latent loads can be presented in the form of a “performance surface” graph. The performance surface is a plot of electric energy consumption as a function of cooling degree days and latent enthalpy days. The above methods are tested on data sets consisting of electric energy consumption data obtained from two buildings and hourly meteorological data. [Copyright &y& Elsevier]

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 a parameter based on the relative decrease of tracer gas concentration in the first minute of system operation dC(1) and on local ventilation efficiency using the local air-change index ϵL.. A system analysis was made for several different operating regimes of personalized ventilation, where changes in air quantity and the direction of supplied air in the breathing zone were applied. The results of the experimental analysis were statistically evaluated, compared, and included in the existing database of previous research for use as supplementary values. The performed analysis has confirmed previous findings as well as the connection between the dC(1) parameter and ventilation effectiveness parameters, especially with the local air-change index. [ABSTRACT FROM AUTHOR]

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/m3, three orders of magnitude higher than in a modern waste incinerator, were measured in the flue gases of a domestic stove when combusting high chlorine coal (0.31%). The PCDD/F concentrations in the flue gases dropped below 0,5 ng TEQ/m3, when low chlorine coal (0.07%) was used. When low chlorine coal was impregnated with NaCl to obtain 0.38% chlorine content, the emission of the PCDD/F increased by two orders of magnitude. Pronounced non-linearity of the PCDD/F concentrations related to chlorine content in the coal was observed. The combustion of the high chlorine coal yielded PCDD/F concentrations in flue gases one order of magnitude lower in a fan cooled chimney when compared to an insulated one, thus indicating formation in the chimney. The influence of flue gas temperature on the PCDD/F emissions was less pronounced when burning low chlorine coal. The predominant pathway of the PCDD/F emissions is via flue gases, 99% of the TEQ in the case of the high chlorine coal for insulated chimney. [ABSTRACT FROM AUTHOR]

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 technologies used in solar applications around the world with the emphasis on two Mediterranean countries, Turkey and Slovenia. Energy savings and CO2 emission reduction potential when TES is used in various solar applications of buildings are also discussed. [Copyright &y& Elsevier]