humidity

The Performance 2 project (2020-2024) is a French national research project that aims to evaluate the long-term performance and durability of Humidity-based Demand Controlled Ventilation (DCV) systems installed in two multi-family social housing buildings, located in Paris and Villeurbanne, France.

The Performance 2 project (2020-2024) is a French national research project that aims to evaluate the durability of Humidity-based Demand Controlled Ventilation (DCV) systems installed in two multi-family social housing buildings (Paris and Villeurbanne) over than 10 years ago. This evaluation includes the analysis of continuous measurements performed on the ventilation system (sensors located close to the air terminal devices) and two additional Indoor Air Quality (IAQ) campaigns including two other monitors placed in the “dry” rooms conducted in 13 dwellings.

Humidity-based DCV systems have been widely used in France for 35 years and are considered as a reference system, including for low-energy residential buildings. The on-going Performance 2 project delivers the preliminary results of a thirteen-year monitoring in thirty social housing apartments.

Humidity-based DCV systems have been widely used in France for 35 years and are considered as a reference system, including for low-energy residential buildings. The on-going Performance 2 project delivers the new results of a thirteen-year monitoring in twenty-two social housing apartments. The involved consortium is composed of Cerema, Univ. Savoie Mont Blanc and two industrials partners: Aereco and Anjos. 

This study introduced a pre-assessment and control tool for indoor air quality (PACT-IAQ) which aimed at multiple pollutant concentrations simulations, pollutant loads estimations and decoration design scheme optimization. Multiple emission sources, sinks, ventilation, pollutant dissemination, and the combined effects of temperature and humidity on material emissions were considered in the tool. Two versions, namely the single zone and multi-zone models, were included in the tool.

Individual effects of temperature and humidity on formaldehyde emissions from manufactured fiberboards have been studied previously, but their combined effects and possible correlation with initial emittable concentration (C0) of building materials have not been reported yet. This paper investigated their combined effects on C0 theoretically from microcosmic perspective. Total formaldehyde content related to humidity and formaldehyde molecular phases affected by temperature in the porous material were considered.

Initial emittable concentration (C0), diffusion coefficient (Dm) and partition coefficient (K) are the three key emission parameters determining formaldehyde emissions from “dry” building materials. Previous studies of humidity effect on formaldehyde emissions were mainly focused on the analysis of steady-state emission rates or concentrations, whereas humidity effects on emission parameters were seldom discussed.

The IEA EBC Annex 68 project on “Indoor Air Quality Design and Control in Low Energy Residential Buildings” has been recently completed. The project considered indoor air pollution loads in dwellings, particularly how such pollutants are emitted in dependency of the hygrothermal conditions: temperature, moisture and air flows. Thus, a proper understanding of the mutual interactions between hygrothermal conditions and pollutants was needed to obtain optimal paradigms for demand-controlled ventilation.

Humidity-based DCV systems have been widely used in France for 35 years and are considered as a reference system, including for low-energy residential buildings. Indeed, most of the new residential buildings, which must be low-energy buildings to comply with the RT 2012 energy performance regulation, are equipped with such systems. Feedbacks from two long-term studies show the durability of the humidity sensitive components and show the robustness of this system to bad maintenance or use by occupants.

Japan is characterized by high humidity in summer and low humidity in winter. Therefore, summer is in a climatic condition where mold is easy to grow, and in fact, mold damage is occurring. Due to improvement of the thermal insulation and airtightness of houses, the temperature in the room is maintained high even in winter, and mold damage occurs. We will introduce the research we have conducted regarding humidity environment and health problems, and discuss future subjects. The outline is as follows.