Despite efforts to mitigate climate change, annual greenhouse gas emissions continue to rise, which may lead to the global warming of our planet. Buildings’ thermal energy needs are inherently linked ...to climate conditions. Consequently, it is crucial to evaluate how climate change affects these energy demands. Despite extensive analysis, a comprehensive assessment involving a diverse range of building types has not been consistently conducted. The primary objective of this research is to perform a coherent evaluation of the influence of climate changes, construction element properties, and the Heating, Ventilation, and Air Conditioning (HVAC) system type of control on the energy requirements of six buildings (residential, services, and commercial). The buildings are considered to be located in a temperate Mediterranean climate. Our focus is on the year 2070, considering three distinct climatic scenarios: (i) maintaining the current climate without further changes, (ii) moderate climate changes, and (iii) extreme climate changes. The buildings are distributed across three different locations, each characterized by unique climatic conditions. Buildings’ envelope features a traditional External Thermal Insulation Composite System (ETICS) and expanded polystyrene (EPS) serves as thermal insulation material. Two critical design factors are explored: EPS thickness ranging from 0 (no insulation) to 12 cm; and horizontal external fixed shading elements varying lengths from 0 (absence) to 150 cm. Six alternative setpoint ranges are assessed for the HVAC system control: three based on the Predicted Mean Vote (PMV) and three based on indoor air temperature (Tair). Results were obtained with a validated in-home software tool. They show that, even under extreme climate conditions, the application of thermal insulation remains energetically favorable; however, its relative importance diminishes as climate severity increases. Then, proper insulation design remains important for energy efficiency. The use of external shading elements for glazing (e.g., overhangs, louvers) proves beneficial in specific cases. As climate changes intensify, the significance of shading elements grows. Thus, strategic placement and design are necessary for good results. The HVAC system’s energy consumption depends on the level of thermal comfort requirements, on the climate characteristics, and on the building’s type of use. As climate change severity intensifies, energy demands for cooling increase, whereas energy needs for heating decrease. However, it is essential to recognize that the impact of climate changes on HVAC system energy consumption significantly depends on the type of building.
This work is focused on the identification of the energy and economic optimal thermal insulation solutions of opaque elements of the envelope of buildings located in Portugal. Five different ...buildings were selected: an apartment, a detached house, a private clinic, a private high school and a medium-sized supermarket. These buildings were supposedly located in three locations, which together represent all climatic possibilities of Portuguese temperate climate. The most common types of thermal insulation were tested, for which three alternative positions within the building envelope(inside, middle, outside) were considered. Thermal insulation thicknesses between 0 (without insulation) and 12 cm were tested.
The optimal solution depends on perspective adopted: energy or economic. In terms of cost, the EPS presents the most promising thermal insulation material and its best location is in the middle of the building envelope. Depending on the climatic zone and the buildings’ typology, the cost-optimally thickness varies between 0 and 10 cm and the better energy thickness varies from 0 to above 12 cm. Regions with more intense climate require higher thermal insulation thicknesses. Residential buildings require higher insulation thickness than the others. Buildings with permanent occupation require higher insulation thicknesses than the ones with intermittent use.
•Energy and economic optimal thermal insulation of Portuguese buildings envelope.•The building stock is represented by 5 buildings of 4 types of use.•All climatic possibilities of the Portuguese Mediterranean climate were considered.•The optimal solution obtained depends on the perspective (energy or economic).•Thermal insulation thicknesses between 0 (no insulation) and 12 cm were tested.
Among the aspects with major impacts on the energy and environmental performance of a building, the thermal insulation of the opaque elements of its envelope stands out. This work assesses the ...influence of the application of thermal insulation to the opaque elements of the building’s envelope on the thermal comfort conditions indoors; moreover, the influence of the thermal insulation on the energy, environmental, and economic costs over the building’s complete life cycle is evaluated. For this purpose, the three most commonly used thermal insulating materials (expanded polystyrene—EPS, extruded polystyrene—XPS, and mineral wool—MW), thicknesses between 0 (without insulation) and 40 cm, five climates (hot, warm, moderate, cold, and very cold), and six types of use (apartment, housing, clinic, school, bank branch, and supermarket) were considered. EPS reveals itself to be the most promising thermal insulation material, both in economic and environmental terms, so it was selected for this study. The EPS’ optimal thickness depends on the building’s type of use, the climate, and the perspective from which the assessment is carried out (energy, environmental, or economic). The results show that the economically optimal thicknesses of thermal insulation are significantly lower than the corresponding ones in environmental terms. Furthermore, the application of thermal insulation to the opaque building’s envelope is more beneficial in energy and environmental terms than from an economic perspective.
The main goal of this research is to assess the thermal comfort quality in residential and non-residential buildings, and its relationship with the corresponding energy and economic costs, the ...building type of use, the severity of the climate, the thermal insulation of opaque elements, the type of control of the Heating, Ventilation and Air Conditioning (HVAC) system and the probable evolution of the energy price. In addition, the financial framework of the building's holder, an aspect with a huge impact on the economic cost of thermal comfort and repeatedly neglected in the literature, is considered together with all relevant parameters related with previous issues. Data were obtained with a validated in-home software. The results demonstrate that better quality of thermal comfort, with lower costs, is achieved through control of the HVAC system with Predicted Mean Vote (PMV) setpoints rather than the traditional control with air temperature (Tair); moreover, the useful thermal energy needs for climatization is substantially higher for buildings with permanent occupation than for those with intermittent use. A significant portion of the thermal comfort cost is related to the investment in the HVAC system, varying between about 20% and 70%. The rise of thermal comfort cost with the increase of the energy price inflation rate is substantially higher in the case of residential buildings. If that inflation rate is high, it will lead to an increase of families in energy poverty.
•All factors with impact on thermal comfort quality, energy and cost were considered.•The influence of relevant parameters missing in the bibliography is considered.•Financial framework of building holder has a strong impact on thermal comfort costs.•Control by PMV setpoints leads to better thermal comfort quality with lower costs.•The escalation of energy tariffs has a huge influence on thermal comfort cost.
The objective of the present contribution is to assess the exposure to hot thermal environments in the Portuguese glass industry. For this purpose a field survey was carried out and the measurements ...took place in industrial units - five industries and nineteen workplaces were considered–so all the results are based on real working conditions. In order to assess the level of heat exposure the Wet Bulb Globe Temperature (WBGT) index and the Predicted Heat Strain (PHS) model, defined in ISO Standards 7243 (1989) and 7933 (2004), respectively, were used. According to the WBGT index, the results show that almost 80% of the workplaces under analysis are prone to heat stress conditions. If the PHS model is considered, the results highlight that the predicted and the maximum sweat rates present equal values in about 40% of the workplaces. In addition, in almost 25% of the workplaces the estimated rectal temperature was higher than 38°C, just for an exposure period of one hour. Thus, the present study brings to light the characteristics of the glass industry in terms of the occupational exposure to hot environments and places this activity sector as one of the most difficult to deal with.
The aim of this work is to investigate the relationship between evaporation from heated water surfaces and mean aero thermal properties of a forced airflow. Flows with Reynolds numbers varying ...between 2475 and 49,503 were considered. Both wind tunnel measurements and numerical simulations were used. The experimental results were obtained in an installation consisting of a low speed wind tunnel and an evaporation tank. The numerical study was performed through a 3D-CFD code. To validate the numerical formulation the predicted results were compared with the experimental measurements for the mass transfer at the free surface of the water tank and with correlations available in the literature. A good agreement was achieved which indicates an interesting capacity of the CFD program to predict the phenomena engaged.
The dependence of the rate of evaporation with air velocity, water–air temperature difference and relative humidity is also addressed. The results obtained with both methodologies clearly show that the rate of evaporation is mainly dependent of the airflow velocity. The water–air temperature difference and the relative humidity also have an important effect, but much less than the airflow velocity. For small airflow velocities the rate of water evaporation is also small and presents only a slightly dependence from the temperature difference and the relative humidity.
•Water evaporation is related with airflow characteristics and air–water temperature difference.•Experimental results obtained in an installation consisting of a low speed wind tunnel and an evaporation tank.•3D-CFD simulation of turbulent flow with coupled heat and mass transfer at a free water surface.•Through a regression analysis of the results some new empirical correlations are introduced for the water evaporation rate.
The present work is dedicated to the study of occupational cold environments in food distribution industrial units. Field measurements and a subjective assessment based on an individual questionnaire ...were considered. The survey was carried out in 5 Portuguese companies. The field measurements include 26 workplaces, while a sample of 160 responses was considered for the subjective assessment. In order to characterize the level of cold exposure, the Required Clothing Insulation Index (IREQ) was adopted. The IREQ index highlights that in the majority of the workplaces the clothing ensembles worn are inadequate, namely in the freezing chambers where the protection provided by clothing is always insufficient. The questionnaires results show that the food distribution sector is characterized by a female population (70.6%), by a young work force (60.7% are less than 35 yr old) and by a population with a medium-length professional career (80.1% in this occupation for less than 10 yr). The incidence of health effects which is higher among women, the distribution of protective clothing (50.0% of the workers indicate one garment) and the significant percentage of workers (>75%) that has more difficulties in performing the activity during the winter represent other important results of the present study.
The main objective of the present work is the assessment of the thermal insulation of clothing ensembles, both in static conditions and considering the effect of body movements. The different ...equations used to calculate the equivalent thermal resistance of the whole body, namely the
serial, the
global and the
parallel methods, are considered and the results are presented and discussed for the basic, the effective and the total clothing insulations. The results show that the dynamic thermal insulation values are always lower than the corresponding static ones. The highest mean relative difference (static-dynamic)/static was obtained with the
parallel method and the lowest with the
serial. For
I
cl
the mean relative differences varied from 0.5 to 13.4% with the
serial method, from 5.6 to 14.6% with the
global and from 7.2 to 17.7% with the
parallel method. In addition, the dynamic tests presents the higher mean relative differences between the calculation methods. The results also show that the
serial method always presents the higher values and the
parallel method the lowest ones. The relative differences between the calculation methods {(
serial-global)/
global and (
parallel-global)/
global} were sometimes significant and associated to the non-uniform distribution of the clothing insulation. In fact, the ensembles with the highest thermal insulation values present the highest differences between the calculation methods.
The present work is dedicated to the study of cold thermal environments in food distribution industrial units through a subjective assessment based on an individual questionnaire which aims to ...describe the working conditions of employees often exposed to cold. The survey was carried out in Portugal and the sample consists of 1575 valid responses obtained in 61 industrial units. The results show that the food distribution activity sector is characterized by a female population (78.1%) and by a young work force (63.4% of the workers are less than 35 years old). Despite the availability of cold protective clothing (52.8% of the workers indicate one garment) its characteristics require improvements. In addition almost 1/3 of the respondents consider the thermal environment cold and 79.6% of the workers report that working in the cold is harder in wintertime. The results also highlight that 37.3% of the workers report having health problems.
•Food distribution industrial sector.•Subjective assessment based on 1575 valid questionnaires.•Extensive statistical analysis.•Detailed characterization of the working conditions.
•Cold devices for preservation of medical products in public healthcare establishments.•Financial needs to maintain operationality of cold equipment in each EU country.•A comparative analysis between ...EU countries is performed.•Identification of the most common types of cold equipment used.•Extrapolation from a sample to the global using a simplified methodology.
This study presents a quantification of the financial needs to maintain the stock of cold equipment for the preservation of medical products in public health care establishments of European Union (EU) countries. The conditions that must be guaranteed, the types of equipment used, the installed capacity, the total annual financial needs and the estimate of its evolution in the near future are addressed.
A field survey involving Portuguese establishments of various types and dimensions was performed in order to assess the currently installed volume by type of equipment.
Through an analysis based on possible scenarios and using a methodology considered adequate, the financial needs to maintain such equipment in operation was estimated for Portugal, for each EU country and for the EU as a whole. The economic value of these amounts in 2017 and following years was obtained assuming the average price of each type of equipment and considering an expected evolution of its value.
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