Conference Agenda

Overview and details of the sessions of this conference. Please select a date or location to show only sessions at that day or location. Please select a single session for detailed view (with abstracts and downloads if available).

Session Overview
Session 34: IAQ, ventilation & pollutants
Friday, 27/Aug/2021:
10:30am - 12:00pm

Session Chair: Prof. Xudong Yang, Tsinghua University
Location: Room 2 - Room 011, Building: 116

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10:30am - 10:45am

Numerical Assessment of Seven Ventilation Systems for Social Residential Buildings based on Indoor Air Quality and Energy Consumption

Guillaume Sérafin, Marc Abadie, Patrice Joubert

LaSIE UMR CNRS 7356, La Rochelle Université

This work presents a modelling approach for evaluating ventilation systems for their ability to provide good indoor air quality in dwellings. Infiltration and ventilation rates are defined by the conventional French 3CL-DPE standard. The case study is a two-bedroom apartment with a shared or separate kitchen and living room. Three natural ventilation options and four mechanical ventilation systems are compared with respect to exposure to PM2.5, NO2 and formaldehyde. Pollutant concentration levels are assessed in each room based on a scenario of daily occupancy, average annual outdoor concentrations and internal sources. The daily exposure of the occupants to the targeted substances allows the comparison of ventilation systems on the basis of the ULR-QAI index developed at LaSIE laboratory from La Rochelle University. For this case study, it results that controlled mechanical systems are much more efficient than natural ventilation systems, especially in the case of an open-plan kitchen.

10:45am - 11:00am

Indoor air quality evaluation in naturally cross-ventilated buildings for education using age of air

Sonny F. Díaz-Calderón1, J. Antonio Castillo2, Guadalupe Huelsz1

1Universidad Nacional Autónoma de México, Mexico; 2Universidad de Sonora, Mexico

Natural ventilation (NV) is a strategy of bioclimatic design, mainly in warm conditions, to promote hygrothermal comfort and indoor air quality (IAQ). Nowadays, COVID- 19 pandemic highlights the review of ventilation standards. Educational buildings are spaces with priority importance. In Mexico, the IAQ standard states a minimum of ACH = 6 1/h for these buildings. The ACH considers NV as being produced by an ideal piston flow and does not provide information of indoor airflow distribution. In this work, age of air associated parameters are proposed, which consider the indoor airflow distribution: the air renovation per hour (ARH) and the renovation parameter R. As application example, an isolated educational building located in a rural region is studied. Four window configurations of cross- ventilation are considered. All configurations have one windward window located at bottom. The configurations axial and upward have one leeward window at bottom and top, respectively. While, configurations corner and upward corner have one lateral side window at bottom and top, respectively. A Computational Fluid Dynamics (CFD) model of the application example is validated with experiments. The axial configuration has the best performance according to ACH, nevertheless has the worst performance according to ARH and R. The results of the present work show that NV evaluation using ACH can lead to wrong decisions. Thus, an improvement of NV standard with age of air associated parameters, as the ones proposed in this work, is recommended.

11:00am - 11:15am

On the Benefits of Whole-building IAQ, Ventilation, Infiltration and Energy Analysis Using Co-simulation between CONTAM and EnergyPlus

William Stuart Dols1, Chad W. Milando2, Lisa Ng1, Steven J. Emmerich1

1NIST, United States of America; 2Boston University, School of Public Health, USA

Publicly available tools to perform whole-building simulation of indoor air quality, ventilation and energy have been available for several decades. Until recently, these tools were developed in isolation of one another. For example, the whole-building contaminant transport and airflow analysis tool, CONTAM, is developed by the National Institute of Standards and Technology (NIST) and the whole-building energy analysis tool, EnergyPlus, is developed by the U.S. Department of Energy (DOE). The ability to couple these tools during runtime has been fairly recently implemented through co-simulation. This enables improved analysis of the interdependent effects of temperature and airflow on contaminant transport and energy use on a whole-building scale using two of the arguably, most capable analysis tools of their kind.

This presentation will focus on the application of co-simulation to the development of a set of coupled reference building models for the purposes of demonstrating the benefits of co-simulation between CONTAM and EnergyPlus. A set of Residential Prototype Building Models available from DOE has been modified by NIST for use with co-simulation between CONTAM and EnergyPlus. These coupled models were utilized to demonstrate the coupling process, the benefits of this coupling with respect to IAQ and energy analysis, and to evaluate multiple whole-building analysis options related to infiltration, ventilation and occupant exposure to contaminants of indoor and outdoor origins.

11:15am - 11:30am

IEA EBC Annex 68 – Consequences on ventilation and hygrothermal operation of buildings

Carsten Rode, Daria Zukowska-Tejsen, Jakub Kolarik

Technical University of Denmark, Denmark

The objective of the IEA EBC Annex 68 Project, “Indoor Air Quality Design and Control in Low Energy Residential Buildings”, has been to develop the fundamental basis for optimal design and control strategies for good Indoor Air Quality (IAQ) in highly energy efficient residential buildings. Focus has been on emission of chemical pollutants from building products and use of ventilation to alleviate IAQ effects. The question has been whether new paradigms for demand control should be developed based on knowledge from this project.
The paper gives an overview of the project’s activities with regards to:
- Gathering of laboratory and field data on pollution sources in buildings.
- Formulation of a so-called “similarity approach” to predict emissions of volatile organic compounds based on knowledge from moisture transfer properties.
- Gathering of a set of contemporary models to simulate the combined heat, air, moisture and pollution conditions of buildings and their assemblies.
Based on this background, the project has identified and described an extended set of amenable ways to optimize the provision of ventilation and air-conditioning and to assess possibilities to bring this knowledge into practice. The paper gives an overview of the suggested solutions and their conditions

11:30am - 11:45am

Development of a Natural Soil Depressurization System Sizing Tool

Marc Abadie1, Zaid Romani1, Michel Burlot1, Jérôme Nicolle2, Pierre Peigné3, Lionel Druette3, Bernard Collignan4, Francis Allard1

1LaSIE UMR CNRS 7356, La Rochelle Université, France; 2TIPEE platform, Lagord, France; 3CERIC, Saint-Symphorien, France; 4CSTB Environment-Health Division, Grenoble, France

This paper presents a summary of the main developments and results achieved in the framework of the French research project called EVAL-SDS. This project aims to analyze the performance of Natural, i.e. without use of fan for extraction, Soil Depressurization Systems (NSDS) to protect the built indoor environment from soil gaseous pollutant (Radon, Volatile Organic Compounds…). In this paper, the aeraulic performance of NSDS is studied i.e. its capacity to extract air from the ground to protect building’s occupants. To this end, we first performed measurements of airflow rates extracted by a NSDS integrated in a test-house during one year. Those data include various weather conditions (stack effect, wind) for several key parameters (wind extractor type, slab air permeability and basement pressure). Then, a dedicated calculation tool has been developed and validated against the experimental results. This numerical model has been used to evaluate the NSDS performance in France for different building heights and ventilation systems. The results show that NSDS succeed in creating a negative pressure under the building slab most of the time and that the extracted airflow rates can be enhanced by better design of wind extractor, association with mechanical insufflating ventilation system and thermal transfer from the building during the heating season.

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