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Abstract Lower heating demands for space heating impose new requirements for the operation of radiators. Contemporary type of new building construction, retrofitted buildings with smaller heat losses and higher requirements for energy efficiency and thermal comfort, demand an improved radiator design and regulation of heat output. As heating systems mostly operate at part loads, it is important to adopt the heat output as quickly as possible to the variable conditions. This paper presents an experimental validation of an improved heat output regulation concept for multi-panel radiators. A novel concept of water flow arrangement for double panel radiators was investigated. The proposed design enables different sequential water flows through each parallel connected panel. The experimental analysis was carried out in two steps: first, the heat output was studied in a nominal steady state at standard testing conditions; second, the radiator was tested at transient conditions. The results show that the implementation of the modified water flow arrangement significantly improves the transient response of heating radiators in terms of reduced time delay and balancing time. An improvement of the regulation ability, expressed as controllability, was also identified. Highlights • Parallel connected panel radiator with sequential water flow arrangement was tested. • Analysis of step heating up process by transient infrared thermography. • Transient response improvement in terms of reduced time delay and balancing time. • Novel regulation concept significantly improves the controllability of heating radiators. [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]

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]

Potential correlation of exposure to polluted air and the spread and co-development of COVID-19 and severe acute respiratory syndrome, caused by SARS-CoV-2, was examined. The emphasis was given on polluted air in the form of suspended particulate matter or liquid particles in gas or air (so-called dust particles). This study was structured as a systematic literature review of multiple research projects carried out across the globe. Impact of the polluted air particles on the virus spread was examined from the temporal and spatial spread. Furthermore, overall impact of particulate matter and COVID-19 disease on human health human was investigated on a microbiological level. Despite some ambiguity, through systematic literature review effect of the polluted air on the increased spread of various viruses was demonstrated. Longer exposure to contaminated airborne dust particles has a negative effect on the human immune system and in the case of infection with COVID 19, may even overload it. This can lead to serious consequences for human health or even cause death. This review article also provides an insight into a more comprehensive analysis of possible correlation between the spreading the virus (SARS-CoV-2) by means of particulate matter and other meteorological variables (such as air temperature and humidity, weather events and climate). [ABSTRACT FROM AUTHOR]

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]

Residential energy demands are expected to change significantly in the future with increasing electrification, energy efficiency, and improved comfort as well as climate change. While many studies have been performed into how the aforementioned influential factors could affect the energy needs of the forthcoming generations, far less are present for how population aging affects the future heating demand. The latter is particularly relevant for Europe and Slovenia as declining fertility rates and lengthening life spans give rise to the increasing ratio of the elderly. In this paper, the future residential space and water heating energy demands of the aging society in Slovenia, using a sample of geographically dispersed nursing homes as a proxy, are estimated. The results are compared against the latest EU reference scenario until 2050, whereby the adjusted estimates differ by up to 9.6%. Thus, the study highlights the need for energy policy to be further refined and redefined to link the energy performance requirements of buildings to specific consumption characteristics of the elderly. [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]

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]