Energies

Research

22 pages, 3511 KiB

Open AccessArticle

On the Retrofit of Existing Buildings with Aerogel Panels: Energy, Environmental and Economic Issues

by Paola Marrone, Francesco Asdrubali, Daniela Venanzi, Federico Orsini, Luca Evangelisti, Claudia Guattari, Roberto De Lieto Vollaro, Lucia Fontana, Gianluca Grazieschi, Paolo Matteucci and Marta Roncone

Energies 2021, 14(5), 1276; https://doi.org/10.3390/en14051276 - 25 Feb 2021

Cited by 12 | Viewed by 2529

Abstract

Among the super insulating materials, aerogel has interesting properties: very low thermal conductivity and density, resistance to high temperatures and transparency. It is a rather expensive material, but incentives in the field can improve its economic attractiveness. Starting from this, the thermal behavior [...] Read more.

Among the super insulating materials, aerogel has interesting properties: very low thermal conductivity and density, resistance to high temperatures and transparency. It is a rather expensive material, but incentives in the field can improve its economic attractiveness. Starting from this, the thermal behavior of a test building entirely insulated with aerogel panels was investigated through an extended experimental campaign. A dynamic simulation model of a case study building was generated to better comprehend the energy savings obtained through aerogel in terms of energy demand over a whole year. The investigation was completed by computing the carbon and energy payback times of various retrofit strategies through a life cycle assessment approach, as well as by a cost-benefit analysis through a probabilistic financial framework. Compared to conventional insulation materials, aerogel is characterized by a higher energy and carbon payback time, but it guarantees better environmental performance in the whole life cycle. From an economic-financial perspective, the aerogel retrofit is the best in the current tax incentive scenario. However, due to its higher lump-sum investment, aerogel’s net present value is very sensitive to tax deductions, and it is riskier than the best comparable materials in less favorable tax scenarios. Full article

(This article belongs to the Special Issue Thermal Behaviour, Energy Efficiency in Buildings and Sustainable Construction)

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15 pages, 2010 KiB

Open AccessArticle

Non-Intrusive Measurements to Incorporate the Air Renovations in Dynamic Models Assessing the In-Situ Thermal Performance of Buildings

by María José Jiménez, José Alberto Díaz, Antonio Javier Alonso, Sergio Castaño and Manuel Pérez

Energies 2021, 14(1), 37; https://doi.org/10.3390/en14010037 - 23 Dec 2020

Cited by 3 | Viewed by 1555

Abstract

This paper reports the analysis of the feasibility to characterise the air leakage and the mechanical ventilation avoiding the intrusiveness of the traditional measurement techniques of the corresponding indicators in buildings. The viability of obtaining the air renovation rate itself from measurements of [...] Read more.

This paper reports the analysis of the feasibility to characterise the air leakage and the mechanical ventilation avoiding the intrusiveness of the traditional measurement techniques of the corresponding indicators in buildings. The viability of obtaining the air renovation rate itself from measurements of the concentration of the metabolic CO₂, and the possibilities to express this rate as function of other climatic variables, are studied. N₂O tracer gas measurements have been taken as reference. A Test Cell and two full size buildings, with and without mechanical ventilation and with different levels of air leakage, are considered as case studies. One-month test campaigns have been used for the reference N₂O tracer gas experiments. Longer periods are available for the analysis based on CO₂ concentration. When the mechanical ventilation is not active, the results indicate significant correlation between the air renovation rate and the wind speed. The agreement between the N₂O reference values and the evolution of the metabolic CO₂ is larger for larger initial values of the CO₂ concentration. When the mechanical ventilation is active, relevant variations have been observed among the N₂O reference values along the test campaigns, without evidencing any correlation with the considered boundary variables. Full article

(This article belongs to the Special Issue Thermal Behaviour, Energy Efficiency in Buildings and Sustainable Construction)

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19 pages, 7781 KiB

Open AccessArticle

A Method for Establishing a Hygrothermally Controlled Test Room for Measuring the Water Vapor Resistivity Characteristics of Construction Materials

by Toba Samuel Olaoye, Mark Dewsbury and Hartwig Kunzel

Energies 2021, 14(1), 4; https://doi.org/10.3390/en14010004 - 22 Dec 2020

Cited by 8 | Viewed by 3533

Abstract

Hygrothermal assessment is essential to the production of healthy and energy efficient buildings. This has given rise to the demand for the development of a hygrothermal laboratory, as input data to hygrothermal modeling tools can only be sourced and validated through appropriate empirical [...] Read more.

Hygrothermal assessment is essential to the production of healthy and energy efficient buildings. This has given rise to the demand for the development of a hygrothermal laboratory, as input data to hygrothermal modeling tools can only be sourced and validated through appropriate empirical measurements in a laboratory. These data are then used to quantify a building’s dynamic characteristic moisture transport vis-a-vis a much more comprehensive energy performance analysis through simulation. This paper discusses the methods used to establish Australia’s first hygrothermal laboratory for testing the water vapor resistivity properties of construction materials. The approach included establishing a climatically controlled hygrothermal test room with an automatic integrated system which controls heating, cooling, humidifying, and de-humidifying as required. The data acquisition for this hygrothermal test room operates with the installation of environmental sensors connected to specific and responsive programming codes. The room was successfully controlled to deliver a relative humidity of 50% with ±1%RH deviation and at 23 °C temperature with ±1 °C fluctuation during the testing of the water vapor diffusion properties of a pliable membrane common in Australian residential construction. To validate the potential of this testing facility, an independent measurement was also conducted at the Fraunhofer Institute of Building Physics laboratory (IBP) Holzkirchen, Germany for the diffusion properties of the same pliable membrane. The inter-laboratory testing results were subjected to statistical analysis of variance, this indicates that there is no significant difference between the result obtained in both laboratories. In conclusion, this paper demonstrates that a low-cost hygrothermally controlled test room can successfully replace the more expensive climatic chamber. Full article

(This article belongs to the Special Issue Thermal Behaviour, Energy Efficiency in Buildings and Sustainable Construction)

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18 pages, 13294 KiB

Open AccessArticle

Assessment of the Impact of Occupants’ Behavior and Climate Change on Heating and Cooling Energy Needs of Buildings

by Gianmarco Fajilla, Marilena De Simone, Luisa F. Cabeza and Luís Bragança

Energies 2020, 13(23), 6468; https://doi.org/10.3390/en13236468 - 07 Dec 2020

Cited by 5 | Viewed by 2162

Abstract

Energy performance of buildings is a worldwide increasing investigated field, due to ever more stringent energy standards aimed at reducing the buildings’ impact on the environment. The purpose of this paper is to assess the impact that occupant behavior and climate change have [...] Read more.

Energy performance of buildings is a worldwide increasing investigated field, due to ever more stringent energy standards aimed at reducing the buildings’ impact on the environment. The purpose of this paper is to assess the impact that occupant behavior and climate change have on the heating and cooling needs of residential buildings. With this aim, data of a questionnaire survey delivered in Southern Italy were used to obtain daily use profiles of natural ventilation, heating, and cooling, both in winter and in summer. Three climatic scenarios were investigated: The current scenario (2020), and two future scenarios (2050 and 2080). The CCWorldWeatherGen tool was used to create the weather files of future climate scenarios, and DesignBuilder was applied to conduct dynamic energy simulations. Firstly, the results obtained for 2020 demonstrated how the occupants’ preferences related to the use of natural ventilation, heating, and cooling systems (daily schedules and temperature setpoints) impact on energy needs. Heating energy needs appeared more affected by the heating schedules, while cooling energy needs were mostly influenced by both natural ventilation and usage schedules. Secondly, due to the temperature rise, substantial decrements of the energy needs for heating and increments of cooling energy needs were observed in all the future scenarios where in addition, the impact of occupant behavior appeared amplified. Full article

(This article belongs to the Special Issue Thermal Behaviour, Energy Efficiency in Buildings and Sustainable Construction)

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19 pages, 7791 KiB

Open AccessArticle

Prediction of Cooling Energy Consumption in Hotel Building Using Machine Learning Techniques

by Marek Borowski and Klaudia Zwolińska

Energies 2020, 13(23), 6226; https://doi.org/10.3390/en13236226 - 26 Nov 2020

Cited by 14 | Viewed by 2210

Abstract

The diversification of energy sources in buildings and the interdependence as well as communication between HVAC installations in the building have resulted in the growing interest in energy load prediction systems that enable proper management of energy resources. In addition, energy storage and [...] Read more.

The diversification of energy sources in buildings and the interdependence as well as communication between HVAC installations in the building have resulted in the growing interest in energy load prediction systems that enable proper management of energy resources. In addition, energy storage and the creation of energy buffers are also important in terms of proper resource management, for which it is necessary to correctly determine energy consumption over time. It is obvious that the consumption of cooling energy depends on meteorological conditions. Knowing the parameters of the outside air and the number of users, it is, therefore, possible to determine the hourly energy consumption of a cooling system in a building with some accuracy. The article presents models of cooling energy prediction in summer for a hotel building in southern Poland. The paper presents two methods that are often used for energy prediction: neural networks and support vector machines. Meteorological data, time data, and occupancy level were used as input parameters. Based on the collected input and output data, various configurations were tested to identify the model with the best accuracy. As the analysis showed, higher prediction accuracy was obtained thanks to the use of neural networks. The best of the proposed models was characterized by the WAPE and CV coefficients of 19.93% and 27.03%, respectively. Full article

(This article belongs to the Special Issue Thermal Behaviour, Energy Efficiency in Buildings and Sustainable Construction)

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16 pages, 2555 KiB

Open AccessArticle

Effect on the Thermal Properties of Mortar Blocks by Using Recycled Glass and Its Application for Social Dwellings

by Vicente Flores-Alés, Alexis Pérez-Fargallo, Jesús A. Pulido Arcas and Carlos Rubio-Bellido

Energies 2020, 13(21), 5702; https://doi.org/10.3390/en13215702 - 31 Oct 2020

Cited by 2 | Viewed by 1896

Abstract

Including recycled waste material in cement mixes, as substitutes for natural aggregates, has resulted in diverse research projects, normally focused on mechanical capacities. In the case of recycled glass as an aggregate, this provides a noticeable improvement in thermal properties, depending on its [...] Read more.

Including recycled waste material in cement mixes, as substitutes for natural aggregates, has resulted in diverse research projects, normally focused on mechanical capacities. In the case of recycled glass as an aggregate, this provides a noticeable improvement in thermal properties, depending on its dosage. This idea raises possible construction solutions that reduce the environmental impact and improves thermal behavior. For this research, an extended building typology that is susceptible to experiencing the risk of energy poverty has been chosen. The typology is typical for social housing, built using mortar blocks with crushed glass. First, the basic thermophysical properties of the mortars were determined by laboratory tests; after that, the dynamic thermal properties of representative constructive solutions using these mortars were simulated in seven representative climate zones in Chile. An analysis methodology based on periodic thermal transmittance, adaptive comfort levels and energy demand was run for the 21 proposed models. In addition, the results show that thermal comfort hours increases significantly in thermal zones 1, 2, 3 and 6; from 23 h up to 199 h during a year. It is in these zones where the distance with respect to the neutral temperature of the m50 solution reduces that of the m25 solution by half; i.e., in zone 1, from −429 °C with the m25 solution to −864 °C with the m50. This research intends to be a starting point to generate an analysis methodology for construction solutions in the built environment, from the point of view of thermal comfort. Full article

(This article belongs to the Special Issue Thermal Behaviour, Energy Efficiency in Buildings and Sustainable Construction)

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20 pages, 2498 KiB

Open AccessArticle

Energy Analyses of Serbian Buildings with Horizontal Overhangs: A Case Study

by Danijela Nikolic, Slobodan Djordjevic, Jasmina Skerlic and Jasna Radulovic

Energies 2020, 13(17), 4577; https://doi.org/10.3390/en13174577 - 03 Sep 2020

Cited by 3 | Viewed by 2273

Abstract

It is well known that nowadays a significant part of the total energy consumption is related to buildings, so research for improving building energy efficiency is very important. This paper presents our investigations about the dimensioning of horizontal overhangs in order to determine [...] Read more.

It is well known that nowadays a significant part of the total energy consumption is related to buildings, so research for improving building energy efficiency is very important. This paper presents our investigations about the dimensioning of horizontal overhangs in order to determine the minimum annual consumption of building primary energy for heating, cooling and lighting. In this investigation, embodied energy for horizontal roof overhangs was taken into account. The annual simulation was carried out for a residential building located in the city of Belgrade (Serbia). Horizontal overhangs (roof and balcony) are positioned to provide shading of all exterior of the building. The building is simulated in the EnergyPlus software environment. The optimization of the overhang size was performed by using the Hooke Jeeves algorithm and plug-in GenOpt program. The objective function minimizes the annual consumption of primary energy for heating, cooling and lighting of the building and energy spent to build overhangs. The simulation results show that the building with optimally sized roof and balcony overhangs consumed 7.12% lessprimary energy for heating, cooling and lighting, compared to the house without overhangs. A 44.15% reduction in cooling energy consumption is also achieved. Full article

(This article belongs to the Special Issue Thermal Behaviour, Energy Efficiency in Buildings and Sustainable Construction)

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20 pages, 4766 KiB

Open AccessArticle

Life-Cycle Assessment of Alternative Envelope Construction for a New House in South-Western Europe: Embodied and Operational Magnitude

by Helena Monteiro, Fausto Freire and John E. Fernández

Energies 2020, 13(16), 4145; https://doi.org/10.3390/en13164145 - 11 Aug 2020

Cited by 10 | Viewed by 2239

Abstract

The building envelope is critical to reducing operational energy in residential buildings. Under moderate climates, as in South-Western Europe (Portugal), thermal operational energy may be substantially reduced with an adequate building envelope selection at the design stage; therefore, it is crucial to assess [...] Read more.

The building envelope is critical to reducing operational energy in residential buildings. Under moderate climates, as in South-Western Europe (Portugal), thermal operational energy may be substantially reduced with an adequate building envelope selection at the design stage; therefore, it is crucial to assess the trade-offs between operational and embodied impacts. In this work, the environmental influence of building envelope construction with varying thermal performance were assessed for a South-Western European house under two operational patterns using life-cycle assessment (LCA) methodology. Five insulation thickness levels (0–12 cm), four total ventilation levels (0.3–1.2 ac/h), three exterior wall alternatives (double brick, concrete, and wood walls), and six insulation materials were studied. Insulation thickness tipping-points were identified for alternative operational patterns and wall envelopes, considering six environmental impact categories. Life-cycle results show that, under a South-Western European climate, the embodied impacts represent twice the operational impact of a new Portuguese house. Insulation played an important role. However, increasing it beyond the tipping-point is counterproductive. Lowering ventilation levels and adopting wood walls reduced the house life-cycle impacts. Cork was the insulation material with the lowest impact. Thus, under a moderate climate, priority should be given to using LCA to select envelope solutions. Full article

(This article belongs to the Special Issue Thermal Behaviour, Energy Efficiency in Buildings and Sustainable Construction)

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22 pages, 6973 KiB

Open AccessArticle

Mechanical and Thermal Performance Characterisation of Compressed Earth Blocks

by Elisabete R. Teixeira, Gilberto Machado, Adilson de P. Junior, Christiane Guarnier, Jorge Fernandes, Sandra M. Silva and Ricardo Mateus

Energies 2020, 13(11), 2978; https://doi.org/10.3390/en13112978 - 10 Jun 2020

Cited by 33 | Viewed by 6969

Abstract

The present research is focused on an experimental investigation to evaluate the mechanical, durability, and thermal performance of compressed earth blocks (CEBs) produced in Portugal. CEBs were analysed in terms of electrical resistivity, ultrasonic pulse velocity, compressive strength, total water absorption, water absorption [...] Read more.

The present research is focused on an experimental investigation to evaluate the mechanical, durability, and thermal performance of compressed earth blocks (CEBs) produced in Portugal. CEBs were analysed in terms of electrical resistivity, ultrasonic pulse velocity, compressive strength, total water absorption, water absorption by capillarity, accelerated erosion test, and thermal transmittance evaluated in a guarded hotbox setup apparatus. Overall, the results showed that compressed earth blocks presented good mechanical and durability properties. Still, they had some issues in terms of porosity due to the particle size distribution of soil used for their production. The compressive strength value obtained was 9 MPa, which is considerably higher than the minimum requirements for compressed earth blocks. Moreover, they presented a heat transfer coefficient of 2.66 W/(m²·K). This heat transfer coefficient means that this type of masonry unit cannot be used in the building envelope without an additional thermal insulation layer but shows that they are suitable to be used in partition walls. Although CEBs have promising characteristics when compared to conventional bricks, results also showed that their proprieties could even be improved if optimisation of the soil mixture is implemented. Full article

(This article belongs to the Special Issue Thermal Behaviour, Energy Efficiency in Buildings and Sustainable Construction)

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21 pages, 11358 KiB

Open AccessArticle

Design and Construction of a New Metering Hot Box for the In Situ Hygrothermal Measurement in Dynamic Conditions of Historic Masonries

by Mirco Andreotti, Marta Calzolari, Pietromaria Davoli, Luisa Dias Pereira, Elena Lucchi and Roberto Malaguti

Energies 2020, 13(11), 2950; https://doi.org/10.3390/en13112950 - 09 Jun 2020

Cited by 39 | Viewed by 3491

Abstract

The main purpose of the HeLLo project is to contribute to data available on the literature on the real hygrothermal behavior of historic walls and the suitability of insulation technologies. Furthermore, it also aims at minimizing the energy simulation errors at the design [...] Read more.

The main purpose of the HeLLo project is to contribute to data available on the literature on the real hygrothermal behavior of historic walls and the suitability of insulation technologies. Furthermore, it also aims at minimizing the energy simulation errors at the design phase and at improving their conservation features. In this framework, one of the preliminary activities of the study is the creation of a real in situ hot box to measure and analyze different insulation technologies applied to a real historic wall, to quantify the hygrothermal performance of a masonry building. Inside this box, ‘traditional’ experiments can be carried out: recording heat flux, surface temperature, and air temperatures, as well as relative humidity values through the use of a new sensing system (composed of thermocouples and temperature/relative humidity combined sensors). Within this paper, the process of development, construction, and validation of this new metering box is exhibited. The new hot box, specifically studied for historic case studies, when compared to other boxes, presents other advantages compared to previous examples, widely exemplified. Full article

(This article belongs to the Special Issue Thermal Behaviour, Energy Efficiency in Buildings and Sustainable Construction)

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25 pages, 7851 KiB

Open AccessArticle

Trombe Wall Thermal Behavior and Energy Efficiency of a Light Steel Frame Compartment: Experimental and Numerical Assessments

by Victor Lohmann and Paulo Santos

Energies 2020, 13(11), 2744; https://doi.org/10.3390/en13112744 - 30 May 2020

Cited by 26 | Viewed by 4459

Abstract

Buildings are seeking renewable energy sources (e.g., solar) and passive devices, such as Trombe walls. However, the thermal performance of Trombe walls depends on many factors. In this work, the thermal behavior and energy efficiency of a Trombe wall in a lightweight steel [...] Read more.

Buildings are seeking renewable energy sources (e.g., solar) and passive devices, such as Trombe walls. However, the thermal performance of Trombe walls depends on many factors. In this work, the thermal behavior and energy efficiency of a Trombe wall in a lightweight steel frame compartment were evaluated, making use of in situ measurements and numerical simulations. Measurements were performed inside two real scale experimental identical cubic modules, exposed to natural exterior weather conditions. Simulations were made using validated advanced dynamic models. The winter Trombe wall benefits were evaluated regarding indoor air temperature increase and heating energy reduction. Moreover, a thermal behavior parametric study was performed. Several comparisons were made: (1) Sunny and cloudy winter week thermal behavior; (2) Office and residential space use heating energy; (3) Two heating set-points (20 °C and 18 °C); (4) Thickness of the Trombe wall air cavity; (5) Thickness of the thermal storage wall; (6) Dimensions of the interior upper/lower vents; (7) Material of the thermal storage wall. It was found that a Trombe wall device could significantly improve the thermal behavior and reduce heating energy consumption. However, if not well designed and controlled (e.g., to mitigate nocturnal heat losses), the Trombe wall thermal and energy benefits could be insignificant and even disadvantageous. Full article

(This article belongs to the Special Issue Thermal Behaviour, Energy Efficiency in Buildings and Sustainable Construction)

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17 pages, 3363 KiB

Open AccessArticle

Model Simplification on Energy and Comfort Simulation Analysis for Residential Building Design in Hot and Arid Climate

by Sara Elhadad, Chro Hama Radha, István Kistelegdi, Bálint Baranyai and János Gyergyák

Energies 2020, 13(8), 1876; https://doi.org/10.3390/en13081876 - 12 Apr 2020

Cited by 17 | Viewed by 2969

Abstract

Accurate building physics performance analysis requires time-consuming, detailed modeling, and calculation time requirement. This paper evaluates the impact of model simplifications on thermal and visual comfort as well as energy performance. In the framework of dynamic zonal thermal simulation, a case study of [...] Read more.

Accurate building physics performance analysis requires time-consuming, detailed modeling, and calculation time requirement. This paper evaluates the impact of model simplifications on thermal and visual comfort as well as energy performance. In the framework of dynamic zonal thermal simulation, a case study of a residential building in hot climate is investigated. A detailed model is created and simplified through four scenarios, by incrementally reducing the number of thermal zones from modeling every space as a separate zone to modeling the building as a single zone. The differences of total energy and comfort performance in the detailed and simplified models are analyzed to evaluate the grade of the simplifications’ accuracy. The results indicate that all simplification scenarios present a marginal average deviation in total energy demand and thermal comfort by less than 20%. Combining rooms with similar thermal features into a zone presents the optimal scenario, while the worst scenario is the single-zone model. Results showed that thermal zone merging as a simulation simplification method has its limitations as well, whereas a too intensive simplification can lead to undesired error rates. The method is well applicable in further early-stage design and development tasks, specifically in large-scale projects. Full article

(This article belongs to the Special Issue Thermal Behaviour, Energy Efficiency in Buildings and Sustainable Construction)

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27 pages, 8419 KiB

Open AccessArticle

Analytical Methods to Estimate the Thermal Transmittance of LSF Walls: Calculation Procedures Review and Accuracy Comparison

by Paulo Santos, Gabriela Lemes and Diogo Mateus

Energies 2020, 13(4), 840; https://doi.org/10.3390/en13040840 - 14 Feb 2020

Cited by 21 | Viewed by 4355

Abstract

An accurate evaluation of the thermal transmittance (

U

-value) of building envelope elements is fundamental for a reliable assessment of their thermal behaviour and energy efficiency. Simplified analytical methods to estimate the

U

-value of building elements could be very useful to [...] Read more.

An accurate evaluation of the thermal transmittance (

U

-value) of building envelope elements is fundamental for a reliable assessment of their thermal behaviour and energy efficiency. Simplified analytical methods to estimate the

U

-value of building elements could be very useful to designers. However, the analytical methods applied to lightweight steel framed (LSF) elements have some specific features, being more challenging to use and to obtain a reliable accurate

U

-value with. In this work, the main analytical methods available in the literature were identified, the calculation procedures were reviewed and their accuracy was evaluated and compared. With this goal, six analytical methods were used to estimate the

U

-values of 80 different LSF wall models. The obtained analytical

U

-values were compared with those provided by numerical simulations, which were used as reference

U

-values. The numerical simulations were performed using a 2D steady-state finite element method (FEM)-based software, THERM. The reliability of these numerical models was ensured by comparison with benchmark values and by an experimental validation. All the evaluated analytical methods showed a quite good accuracy performance, the worst accuracy being found in cold frame walls. The best and worst precisions were found in the Modified Zone Method and in the Gorgolewski Method 2, respectively. Very surprisingly, the ISO 6946 Combined Method showed a better average precision than other two methods, which were specifically developed for LSF elements. Full article

(This article belongs to the Special Issue Thermal Behaviour, Energy Efficiency in Buildings and Sustainable Construction)

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12 pages, 5360 KiB

Open AccessArticle

Evaluation on Overheating Risk of a Typical Norwegian Residential Building under Future Extreme Weather Conditions

by Zhiyong Tian, Shicong Zhang, Jie Deng and Bozena Dorota Hrynyszyn

Energies 2020, 13(3), 658; https://doi.org/10.3390/en13030658 - 04 Feb 2020

Cited by 12 | Viewed by 2422

Abstract

As the temperature in the summer period in Norway has been always moderate, little study on the indoor comfort of typical Norwegian residential buildings in summer seasons can be found. Heat waves have attacked Norway in recent years, including in 2018 and 2019. [...] Read more.

As the temperature in the summer period in Norway has been always moderate, little study on the indoor comfort of typical Norwegian residential buildings in summer seasons can be found. Heat waves have attacked Norway in recent years, including in 2018 and 2019. Zero energy buildings, even neighborhoods, have been a hot research topic in Norway. There is overheating risk in typical Norwegian residential buildings without cooling devices installed under these uncommon weather conditions, like the hot summers in 2018 and 2019. Three weather scenarios consisting of present-day weather data, 2050 weather data, and 2080 weather data are investigated in this study. The overheating risk of a typical Norwegian residential building is evaluated under these three weather scenarios. 72 scenarios are simulated in this study, including different orientations, window-to-wall ratios, and infiltration rates. Two different overheating evaluation criteria and guidelines, the Passive House Planning Package (PHPP) and the CIBSE TM 59, are compared in this study. Full article

(This article belongs to the Special Issue Thermal Behaviour, Energy Efficiency in Buildings and Sustainable Construction)

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29 pages, 15701 KiB

Open AccessArticle

Thermal Performance and Comfort Condition Analysis in a Vernacular Building with a Glazed Balcony

by Jorge Fernandes, Raphaele Malheiro, Maria de Fátima Castro, Helena Gervásio, Sandra Monteiro Silva and Ricardo Mateus

Energies 2020, 13(3), 624; https://doi.org/10.3390/en13030624 - 01 Feb 2020

Cited by 20 | Viewed by 3983

Abstract

The increase in global environmental problems requires more environmentally efficient construction. Vernacular passive strategies can play an important role in helping reducing energy use and CO₂ emissions related to buildings. This paper studies the use of glazed balconies in the North of [...] Read more.

The increase in global environmental problems requires more environmentally efficient construction. Vernacular passive strategies can play an important role in helping reducing energy use and CO₂ emissions related to buildings. This paper studies the use of glazed balconies in the North of Portugal as a strategy to capture solar gains and reduce heat losses. The purpose is understanding thermal performance and comfort conditions provided by this passive heating strategy. The methodology includes objective (short and long-term monitoring), to evaluate the different parameters affecting thermal comfort and air quality, and subjective assessments to assess occupants’ perception regarding thermal sensation. The results show that the use of glazed balconies as a passive heating strategy in a climate with cold winters is viable. During the mid-seasons, the rooms with balcony have adequate comfort conditions. In the heating season, it is possible to achieve comfort conditions in sunny days while in the cooling season there is a risk of overheating. Regarding indoor air quality, carbon dioxide concentrations were low, but the average radon concentration measured was high when the building was unoccupied, rapidly decreasing to acceptable values, during occupation periods when a minimum ventilation rate was promoted. Occupants’ actions were essential to improving building behavior. Full article

(This article belongs to the Special Issue Thermal Behaviour, Energy Efficiency in Buildings and Sustainable Construction)

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20 pages, 6253 KiB

Open AccessArticle

Analysis of the Thermal Behavior of an Earthbag Building in Mediterranean Continental Climate: Monitoring and Simulation

by Lídia Rincón, Ariadna Carrobé, Marc Medrano, Cristian Solé, Albert Castell and Ingrid Martorell

Energies 2020, 13(1), 162; https://doi.org/10.3390/en13010162 - 30 Dec 2019

Cited by 7 | Viewed by 4544

Abstract

Nearly 30% of humanity lives in earthen dwellings. Earthbag is a sustainable, cheap, feasible and comfortable option for emergency housing. A comparative monitoring-simulation analysis of the hygrothermal behavior of an Earthbag dwelling in Mediterranean continental climate, designed under bioclimatic criteria, is presented. The [...] Read more.

Nearly 30% of humanity lives in earthen dwellings. Earthbag is a sustainable, cheap, feasible and comfortable option for emergency housing. A comparative monitoring-simulation analysis of the hygrothermal behavior of an Earthbag dwelling in Mediterranean continental climate, designed under bioclimatic criteria, is presented. The dome shape Earthbag dwelling has a net floor area of 7.07 m², a glass door facing south and two confronted windows in the east and west facades. A numerical model (EnergyPlus v8.8) was designed for comparison. Twenty-four hour cross ventilation, night cross ventilation, and no ventilation in free floating mode and a controlled indoor temperature were the tested scenarios. Comparisons between experimental data and simulation show a good match in temperature behavior for the scenarios studied. Reductions of 90% in summer and 88% in winter, in the interior thermal amplitude with respect to exterior temperatures are found. Position of the glazed openings was fundamental in the direct solar gains, contributing to the increase of temperature in 1.31 °C in winter and 1.37 °C in the equinox. Night ventilation in the summer period had a good performance as a passive system. Passive solar gains made a reduction of heating energy consumption of 2.3% in winter and 8.9% in equinox. Full article

(This article belongs to the Special Issue Thermal Behaviour, Energy Efficiency in Buildings and Sustainable Construction)

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18 pages, 5950 KiB

Open AccessArticle

Impact of Heating Control Strategy and Occupant Behavior on the Energy Consumption in a Building with Natural Ventilation in Poland

by Aniela Kaminska

Energies 2019, 12(22), 4304; https://doi.org/10.3390/en12224304 - 12 Nov 2019

Cited by 9 | Viewed by 2749

Abstract

This study aims to provide an experimental assessment of energy consumption in an existing public building in Poland, in order to analyze the impact of occupant behavior on that consumption. The building is naturally ventilated and the occupants have the freedom to change [...] Read more.

This study aims to provide an experimental assessment of energy consumption in an existing public building in Poland, in order to analyze the impact of occupant behavior on that consumption. The building is naturally ventilated and the occupants have the freedom to change the temperature set point and open or close the windows. The energy consumption is calculated and the calculation results are compared with the experimental data. An analysis of occupants’ behavior has revealed that they choose temperature set points in a wide range recognized as thermal comfort, and window opening is accidental and difficult to predict. The implemented heating control algorithms take into account the strong influence of individual occupant preferences on the feeling of comfort. The energy consumption assessment has revealed that the lowering of temperature set point by 1 °C results in an energy saving of about 5%. Comparisons of energy consumption with heating control and without any controls showed that the potential for energy reduction due to heating control reached approximately 10%. The use of windows control, which allows to turn off the heating after opening the window and its impact on energy savings have been discussed as well. Full article

(This article belongs to the Special Issue Thermal Behaviour, Energy Efficiency in Buildings and Sustainable Construction)

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15 pages, 2396 KiB

Open AccessArticle

Creating Statistics for China’s Building Energy Consumption Using an Adapted Energy Balance Sheet

by Mingshun Zhang, Xuan Ge, Ya Zhao and Chun Xia-Bauer

Energies 2019, 12(22), 4293; https://doi.org/10.3390/en12224293 - 11 Nov 2019

Cited by 10 | Viewed by 2526

Abstract

China’s regular energy statistics does not include the building sector, and data on building energy demand is included in other types of energy consumption in the Energy Balance Sheet (EBS). Therefore data on building energy demand is not collected based on statistics, but [...] Read more.

China’s regular energy statistics does not include the building sector, and data on building energy demand is included in other types of energy consumption in the Energy Balance Sheet (EBS). Therefore data on building energy demand is not collected based on statistics, but rather calculated or estimated by various approaches in China. This study aims at developing and testing China’s building energy statistics by applying an adapted EBS. The advantage of the adapted EBS is that statistical data is from the regular statistical system and no additional statistical efforts are needed. The research result shows that the adapted EBS can be included in China regular energy statistical system and can be standardized in a transparent way. Testing of the adapted EBS shows that China’s building energy demand has shown an annual increase of 7.6% since 2001, and a lower contribution to the total energy demand as compared to the developed world. There is also a close link to lifestyle and living standard while industrial energy demand is mainly driven by economy and decoupling of building energy demand with increasing of building floor area, this is due to a considerable improvement of building energy efficiency. The adapted EBS creates a method for China conducting statistics of building energy consumption at the sector level in a uniform way and serves as the basis for any sound building energy efficiency policy decisions. Full article

(This article belongs to the Special Issue Thermal Behaviour, Energy Efficiency in Buildings and Sustainable Construction)

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20 pages, 6553 KiB

Open AccessArticle

Thermal Transmittance of Internal Partition and External Facade LSF Walls: A Parametric Study

by Paulo Santos, Gabriela Lemes and Diogo Mateus

Energies 2019, 12(14), 2671; https://doi.org/10.3390/en12142671 - 11 Jul 2019

Cited by 27 | Viewed by 4203

Abstract

Light steel framed (LSF) construction is becoming widespread as a quick, clean and flexible construction system. However, these LSF elements need to be well designed and protected against undesired thermal bridges caused by the steel high thermal conductivity. To reduce energy consumption in [...] Read more.

Light steel framed (LSF) construction is becoming widespread as a quick, clean and flexible construction system. However, these LSF elements need to be well designed and protected against undesired thermal bridges caused by the steel high thermal conductivity. To reduce energy consumption in buildings it is necessary to understand how heat transfer happens in all kinds of walls and their configurations, and to adequately reduce the heat loss through them by decreasing its thermal transmittance (

U

-value). In this work, numerical simulations are performed to assess different setups for two kinds of LSF walls: an interior partition wall and an exterior facade wall. Several parameters were evaluated separately to measure their influence on the wall

U

-value, and the addition of other elements was tested (e.g., thermal break strips) with the aim of achieving better thermal performances. The simulation modeling of a LSF interior partition with thermal break strips indicated a 24%

U

-value reduction in comparison with the reference case of using the LSF alone (

U

= 0.449 W/(m².K)). However, when the clearance between the steel studs was simulated with only 300 mm there was a 29% increase, due to the increase of steel material within the wall structure. For exterior facade walls (

U

= 0.276 W/(m².K)), the model with 80 mm of expanded polystyrene (EPS) in the exterior thermal insulation composite system (ETICS) reduced the thermal transmittance by 19%. Moreover, when the EPS was removed the

U

-value increased by 79%. Full article

(This article belongs to the Special Issue Thermal Behaviour, Energy Efficiency in Buildings and Sustainable Construction)

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39 pages, 7390 KiB

Open AccessArticle

Determination of the Insulation Solution that Leads to Lower CO₂ Emissions during the Construction Phase of a Building

by María José Bastante-Ceca, Alberto Cerezo-Narváez, José-María Piñero-Vilela and Andrés Pastor-Fernández

Energies 2019, 12(12), 2400; https://doi.org/10.3390/en12122400 - 21 Jun 2019

Cited by 9 | Viewed by 3440

Abstract

The characteristics of the envelope of a building determine, together with other factors, its consumption of energy. Additionally, the climate zone and insulation material may vary the minimum insulation thickness of walls and roofs, making it different, according to cooling down or warming [...] Read more.

The characteristics of the envelope of a building determine, together with other factors, its consumption of energy. Additionally, the climate zone and insulation material may vary the minimum insulation thickness of walls and roofs, making it different, according to cooling down or warming up the home. Spanish legislation establishes different maximum values for energy demand according to different climate area both for heating and for cooling. This paper presents the results of a study that determines the influence of many variables as the climate zone or the orientation, among others, in the optimization of thickness insulation in residential homes in Spain to reduce the CO₂ emissions embodied. To do that, 12 representative cities in Spain corresponding to different climate zones, four orientations, two constructive solutions, and four different configurations of the same house have been combined, for three different hypotheses and four insulation materials, resulting in 4608 cases of study. The results show that, under equal conditions on energy demand, the optimal insulation requirements are determined by heating necessities more than by cooling ones. In addition, a higher insulation thickness need does not necessarily mean more CO₂ emissions, since it can be compensated with a lower Global Warming Potential characterization factor that is associated to the insulation material. The findings of this study can serve to designers and architects to establish the better combination of the variables that are involved in order to minimize the CO₂ emissions embodied during the construction phase of a building, making it more energy efficient. Full article

(This article belongs to the Special Issue Thermal Behaviour, Energy Efficiency in Buildings and Sustainable Construction)

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