Airtightness and Controllable Natural Ventilation for Buildings: Challenges and Trends

A special issue of Buildings (ISSN 2075-5309). This special issue belongs to the section "Building Energy, Physics, Environment, and Systems".

Deadline for manuscript submissions: closed (31 May 2020) | Viewed by 29995

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Guest Editor
CONSTRUCT-LFC, Faculty of Engineering (FEUP), University of Porto, Porto, Portugal, Rua Dr. Roberto Frias s/n, 4200-465 Porto, Portugal
Interests: Natural ventilation and airtightness; Energy efficiency; Thermal comfort; Hygrothermal performance of buildings; Smart buildings and occupant behaviour; Durability of buildings and components

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Guest Editor
1. CONSTRUCT-LFC, Faculty of Engineering (FEUP), University of Porto, Porto, Portugal, Rua Dr. Roberto Frias s/n, 4200-465 Porto, Portugal
2. Polytechnic Institute of Viseu, School of Technology and Management, Department of Civil Engineering, Campus Politécnico de Repeses, 3504-510 Viseu, Portugal
Interests: natural ventilation and airtightness; energy efficiency; thermal comfort; indoor environmental quality; infrared thermography and in situ testing of buildings or building components; heat, air and moisture transfer in buildings or building components; building simulation; multi-objective optimization
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Special Issue Information

Dear Colleagues,

Combining the concerns regarding the airtightness and natural ventilation of buildings, their energy performance and indoor air quality remains a challenge for the technical and scientific community. The climatic diversity of potential building locations adds an additional layer of complexity to the problem.

Innovation in materials and constructive solutions is an excellent opportunity to be taken advantage of, but aspects related to the occupants' behaviour and their expectations in terms of thermal comfort cannot be forgotten.

This Special Issue aims at stimulating the exchange of ideas and knowledge on the airtightness and controllable natural ventilation of buildings. To this purpose, original contributions containing theoretical and experimental research, case studies or a comprehensive state of art discussion are welcome for possible publication. Relevant topics for this Special Issue include, but are not limited to the following:

  • Airtightness in buildings with natural ventilation
  • Implementation of natural ventilation strategies
  • New materials and constructive solutions
  • Smart control of natural ventilation
  • Natural ventilation and occupant behaviour
  • Natural ventilation and thermal comfort
  • Natural ventilation and energy efficiency

Dr. Nuno M. M. Ramos
Dr. Ricardo M. S. F. Almeida
Guest Editors

Manuscript Submission Information

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Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Buildings is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Airtightness
  • Natural ventilation
  • Smart ventilation
  • Energy efficiency
  • IAQ
  • Ventilation cooling

Published Papers (5 papers)

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Research

18 pages, 2715 KiB  
Article
The Impacts of Air Leakage Paths and Airtightness Levels on Air Change Rates
by Vitor E. M. Cardoso, Pedro F. Pereira, Nuno M. M. Ramos and Ricardo M. S. F. Almeida
Buildings 2020, 10(3), 55; https://doi.org/10.3390/buildings10030055 - 12 Mar 2020
Cited by 21 | Viewed by 5744
Abstract
Southern European countries have milder climatic conditions that differ from their colder northern counterparts, which greatly influence indoor ventilation strategies. The relation between a building’s airtightness and the air change rates remains a topic to be fully tackled in these countries, since natural [...] Read more.
Southern European countries have milder climatic conditions that differ from their colder northern counterparts, which greatly influence indoor ventilation strategies. The relation between a building’s airtightness and the air change rates remains a topic to be fully tackled in these countries, since natural ventilation is very frequent. In this work, the ventilation and airtightness of a case study were analyzed in-depth to support a discussion on this topic. CO2 concentration decay and blower-door measurements were used to characterize the infiltration and ventilation conditions of the case study. The case study represents a common Portuguese situation, with highly permeable envelopes, combined with highly variable air change rates. Transient simulations were carried out for the comparison of scenarios where different configurations of possible air paths were analyzed. The simulations included both natural and mechanical ventilation scenarios. An air sweeping effect from bedroom to bathroom only occurred when the mechanical extraction ventilation (MEV) was on. Different air leakage path configurations resulted in substantial offsets, up to 63%, of the air change rate (ACH) due to natural occurring forces. The results confirmed that the relation between airtightness and air change rates should be carefully analyzed in southern European countries, as indoor air quality, comfort of occupants, and energy efficiency are highly influenced by the considered variables. Full article
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13 pages, 1921 KiB  
Article
CO2 Concentration and Occupants’ Symptoms in Naturally Ventilated Schools in Mediterranean Climate
by Jesica Fernández-Agüera, Miguel Ángel Campano, Samuel Domínguez-Amarillo, Ignacio Acosta and Juan José Sendra
Buildings 2019, 9(9), 197; https://doi.org/10.3390/buildings9090197 - 29 Aug 2019
Cited by 25 | Viewed by 5674
Abstract
A large part of the school building stock in Andalusia lacks ventilation facilities, so that the air renewal of the classrooms is achieved through the building envelope (air infiltration) or the opening of windows. This research analyses the airtightness of the classrooms in [...] Read more.
A large part of the school building stock in Andalusia lacks ventilation facilities, so that the air renewal of the classrooms is achieved through the building envelope (air infiltration) or the opening of windows. This research analyses the airtightness of the classrooms in Andalusia and the evolution of CO2 concentration during school hours through in situ monitoring. Pressurization and depressurization tests were performed in 42 classrooms and CO2 concentration was measured in two different periods, winter and midseason, to study the impact of the different levels of aperture of windows. About 917 students (11–17 years of age) were surveyed on symptoms and effects on their health. The mean n50 values are about 7 h−1, whereas the average CO2 concentration values are about 1878 ppm, with 42% of the case studies displaying concentrations above 2000 ppm with windows closed. Full article
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15 pages, 2818 KiB  
Article
Air Leakage of Joints Filled with Polyurethane Foam
by Jaanus Hallik, Heleen Gustavson and Targo Kalamees
Buildings 2019, 9(7), 172; https://doi.org/10.3390/buildings9070172 - 19 Jul 2019
Cited by 10 | Viewed by 4967
Abstract
Air leakage through the building envelope joints is usually one of the main reasons why airtightness targets are not achieved. The objective of this study was to analyse the air leakage of joints filled with polyurethane foam and its influencing factors. Wooden test [...] Read more.
Air leakage through the building envelope joints is usually one of the main reasons why airtightness targets are not achieved. The objective of this study was to analyse the air leakage of joints filled with polyurethane foam and its influencing factors. Wooden test specimens (54 in total) with planed, sawn and plastic-coated cavities and two cavity thicknesses were filled with three different polyurethane foams and tested according to standard EN 12114. The surface type and thickness of the joint had a significant effect on the air leakage of joints filled with polyurethane foam. In laboratory conditions, a consistent and very low air leakage rate was obtained with planed timber surfaces. Joints with plastic-coated and sawn timber surfaces performed worse, on average, by a factor of two or more and contributed to very variable airtightness, with up to 28% and 50% of the test specimens failing the airtightness testing. On the basis of the high ‘failure rate’, polyurethane foam may classify as a not completely trustworthy solution in guaranteeing the airtightness of construction joints. A comparison of estimated and previously measured overall airtightness of an entire building envelope showed dependency on ‘failure rate’ rather than on average measured leakage rate. Full article
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17 pages, 4913 KiB  
Article
Impact of Natural Ventilation on the Thermal and Energy Performance of Buildings in a Mediterranean Climate
by A. Moret Rodrigues, Miguel Santos, M. Glória Gomes and Rogério Duarte
Buildings 2019, 9(5), 123; https://doi.org/10.3390/buildings9050123 - 15 May 2019
Cited by 30 | Viewed by 4851
Abstract
Natural ventilation plays an important role on the thermal and energy performance of a building. The present study aims to analyze the natural ventilation conditions of a dwelling in a Mediterranean climate and their impacts on the thermal and energy performance using an [...] Read more.
Natural ventilation plays an important role on the thermal and energy performance of a building. The present study aims to analyze the natural ventilation conditions of a dwelling in a Mediterranean climate and their impacts on the thermal and energy performance using an advanced building energy simulation tool. Several multi-zone simulations were carried out. In the summer, the simulations were performed under free-floating conditions, whereas in the winter they were carried out under controlled temperature conditions. In the summer, ventilation scenarios with windows opened during certain periods of time and with or without permanent openings in the facades were analyzed. The existence of permanent openings proved to be an important factor of temperature control by lowering the average indoor zone temperatures during the day. Cross-ventilation also showed to be effective. In the winter, we simulated the existence or absence of permanent openings for room ventilation and their surface area. The results showed that the stack effect plays an important role in the ventilation and that in general it outperforms the wind effect. Sizing permanent openings according to the standard guidelines proved to be adequate in providing the expected ventilation rates on an average basis. Full article
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20 pages, 4070 KiB  
Article
The Effect of Ventilation Strategies on Indoor Air Quality and Energy Consumptions in Classrooms
by Luca Stabile, Angelamaria Massimo, Laura Canale, Aldo Russi, Alexandro Andrade and Marco Dell’Isola
Buildings 2019, 9(5), 110; https://doi.org/10.3390/buildings9050110 - 2 May 2019
Cited by 36 | Viewed by 7836
Abstract
Most of the school buildings in Italy are high energy-demanding buildings with no ad-hoc ventilation systems (i.e., naturally-ventilated buildings). Therefore, reducing the heat losses of schools represent the main aspect to be dealt with. Nonetheless, the indoor air quality of the building should [...] Read more.
Most of the school buildings in Italy are high energy-demanding buildings with no ad-hoc ventilation systems (i.e., naturally-ventilated buildings). Therefore, reducing the heat losses of schools represent the main aspect to be dealt with. Nonetheless, the indoor air quality of the building should be simultaneously considered. Indeed, to date, energy consumptions and air quality are considered as incompatible aspects especially in naturally-ventilated buildings. The aim of the present paper is to evaluate the effect of different ventilation and airing strategies on both indoor air quality and energy consumptions in high energy-demanding naturally-ventilated classrooms. To this purpose, an Italian test-classroom, characterized in terms of air permeability and thermophysical parameters of the envelope, was investigated by means of experimental analyses and simulations through CO2 mass balance equation during the heating season. The air quality was assessed in terms of indoor CO2 concentrations whereas the energy consumptions were evaluated through the asset rating approach. Results clearly report that not adequate indoor CO2 concentrations are measured in the classroom for free-running ventilation scenarios even in low densely populated conditions (2.2 m2 person−1), whereas scheduled airing procedures can reduce the indoor CO2 levels at the cost of higher energy need for ventilation. In particular, when airing periods leading to the air exchange rate required by standards are adopted, the CO2 concentration can decrease to values lower than 1000 ppm, but the ventilation losses increase up to 36% of the overall energy need for space heating of the classroom. On the contrary, when the same air exchange rate is applied through mechanical ventilation systems equipped with heat recovery units, the ventilation energy loss contribution decreases to 5% and the overall energy saving results higher than 30%. Such energy-saving was found even higher for occupancy scenarios characterized by more densely populated conditions of the classroom typically occurring in Italian classrooms. Full article
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