Correlation between Indoor Environmental Data and Biometric Parameters for the Impact Assessment of a Living Wall in a ZEB Lab

Abstract

Users’ satisfaction in indoor spaces plays a key role in building design. In recent years, scientific research has focused more and more on the effects produced by the presence of greenery solutions in indoor environments. In this study, the Internet of Things (IoT) concept is used to define an effective solution to monitor indoor environmental parameters, along with the biometric data of users involved in an experimental campaign conducted in a Zero Energy Building laboratory where a living wall has been installed. The growing interest in the key theory of the IoT allows for the development of promising frameworks used to create datasets usually managed with Machine Learning (ML) approaches. Following this tendency, the dataset derived by the proposed infield research has been managed with different ML algorithms in order to identify the most suitable model and influential variables, among the environmental and biometric ones, that can be used to identify the plant configuration. The obtained results highlight how the eXtreme Gradient Boosting (XGBoost)-based model can obtain the best average accuracy score to predict the plant configuration considering both a selection of environmental parameters and biometric data as input values. Moreover, the XGBoost model has been used to identify the users with the highest accuracy considering a combination of picked biometric and environmental features. Finally, a new Green View Factor index has been introduced to characterize how greenery has an impact on the indoor space and it can be used to compare different studies where green elements have been used.

Benefits of Using Plants in Indoor Environments: Exploring Common Research Gaps

“…The papers reviewed refer mostly to "green facades" (vegetation growing against vertical surface) and "living walls" [5,26,33]-or "green wall" [34]-where the plants root in a structural support anchored to the host building.…”

“…The unit of measure reports the number of plants present within a set area. It is used to describe living walls [13,16,26,34] as well as the plants present within an architectural space [36].…”

“…The index of greenness (in %) is calculated on a flat surface (a photo), taking into account the angle of vision of a person [37]. The Green View Factor (GVF) is calculated as a fraction (dimensionless between 0 and 1) of a hemispheric surface being the fisheye caption of the indoor space [26].…”

“…Different measures describing the exchange and the movement of the air within the testing space. Mentioned aspects include: air freshness (mean age of the indoor air [17]), natural ventilation [30], air speed (air flow [11], air velocity [16,26]), turbulence (use of a chamber fan [22,27], air direction [16]), airtight conditions [27,29].…”

Psychophysiological Response According to the Greenness Index of Subway Station Space

“…In the United States, the WELL Building Standard was developed in 2012, which emphasizes accessibility to nature for the health of people in buildings. Modern people who spend a considerable amount of time inside everyday [ 9 ] are interested in creating a pleasant and healthy environment, and their desire to introduce natural elements into interior spaces, as primitive elements for psychological stability and relaxation, is increasing [ 10 , 11 , 12 , 13 ]. Furthermore, subway users exhibit various use patterns apart from transportation, including meeting and resting; therefore, they are recognizing the necessity of environmental improvement through greening.…”