Project Summary Report - IEA EBC Annex 68 Indoor Air Quality Design and Control in Low Energy Residential Buildings

Abstract

New dwellings or deeply renovated existing dwellings are designed to be energy efficient, and have airtight structures. This leads to a risk of high indoor pollutant loads due to activities and emissions from materials in contact with indoor air. Ventilation must be dosed at the right volume of clean air, efficiently distributed in the occupant zone and with proper scheduling in order to keep indoor pollutant concentrations low, while not increasing the energy need. Building designers, contractors, owners and operators, and decision makers need the newest knowledge on how to operate ventilation to achieve this. The project has focused on new and existing residential buildings, although it should be underlined that many findings may also be relevant to other building types. At the onset of the project, the existing indicators for indoor air quality (IAQ) were reviewed and indicators were defined that would specifically facilitate the other subtasks in this project. The IAQ indicators to be studied were documented in a report, which collected state of the art information and suggested a principle in the form of a “dashboard” on how to balance the combination of the most significant among many pollutants to be considered. The dashboard also highlighted the energy performance aspect. A main result of the project is an easy to understand and practically applicable collection of experiences with design and operational strategies to achieve optimal energy performance and high IAQ in residential buildings. The collection is intended for those involved in the construction and maintenance of buildings. Furthermore, the project presents a modelling framework and design tools, suitable for integrated and coordinated design of buildings with low energy consumption and high IAQ. With regards to pollutants in buildings, data and models have been applied on sources and sinks of pollutant emissions to estimate the net pollutant loads over time under realistic environmental conditions. This is supported by databases on the properties of materials with respect to pollutant emissions. Finally, field tests and case studies were documented for different climatic zones as well as methodologies to carry out such testing. Specifically, this activity targeted industry partners, building owners and operators. The project was carried out with contributions from researchers from some 39 research institutions from 15 countries worldwide, while one participant was a global enterprise that supplies building products and solutions in many areas. Several local stakeholders such as consultants and HVAC manufacturers and associations have been visitors to the project when expert meetings were held semi-annually in different countries. Meetings were usually planned to be held in conjunction with relevant conferences such as by AIVC, ASHRAE but also Indoor Air, IBPC and IAQVEC conferences. The project has also fostered input to meetings in the interest group “CHAMPS” on Combined Heat, Air, Moisture and Pollutant Simulation, which convenes annually in different places of the world. An important lead from the project to policy makers is to facilitate possibility by legislation that residential buildings may be operated flexibly and intelligently with regards to demand control of building ventilation in a manner that considers realistic hygrothermal and pollutants loads in buildings. Furthermore, the project has highlighted the need for more quality management since traditional and novel mechanical ventilation concepts as presented in this project all have in common that quality assurance during design, construction and operation is crucial for success, i.e. high IAQ and comfort while minimizing energy use. Consequently, a framework for quality assurance and inspection is needed.