Methods to reduce the CO₂concentration of educational buildings utilizing internal ventilation by transferred air

Abstract

The aim of this study is to develop internal ventilation by transferred air to achieve a good indoor climate with low energy consumption in educational buildings with constant air volume (CAV) ventilation. Both measurements of CO2 concentration and a multi-room calculation model are presented. The study analyzes how to use more efficiently the available spaces and the capacity of CAV ventilation systems in existing buildings and the impact this has on the indoor air quality and the energy consumption of the ventilation. The temperature differences can be used to create natural ventilation airflows between neighboring spaces. The behavior of temperature-driven airflows between rooms was studied and included in the calculation model. The effect of openings between neighboring spaces, such as doors or large apertures in the walls, on the CO2 concentration was studied in different classrooms. The air temperatures and CO2 concentrations were measured using a wireless, internet-based measurement system. The multi-room calculation model predicted the CO2 concentration in the rooms, which was then compared with the measured ones. Using transferred air between occupied and unoccupied spaces can noticeably reduce the total mechanical ventilation rates needed to keep a low CO2 concentration.

Environmental and Ventilation Assessment in Child Day Care Centers in Porto: The Envirh Project

“…Our results indicated low specific airflow rates that possibly Downloaded by [Florida International University] at 07:13 28 December 2014 compromise IAQ and occupants comfort and, due to the low ventilation rate, potentiate airborne contaminant transmission (Lim et al, 2010;Sun et al, 2011). Kalema and Viot (2013) found that the use of transferred air between rooms created a flexible and energy-efficient ventilation alternative to maintain a low CO 2 concentration in educational buildings in situations where there is a constant air volume ventilation and where the use of the space is changed.…”

Assessment and improvement of indoor environmental quality in a primary school

“…As a result, indoor air CO 2 concentration in the pilot classroom was modeled to determine the design flow rate for the mechanical ventilation to be installed. A CO 2 mass balance (Equation 1) as it was recently used by Kalema and Viot (2014) was employed to model the concentrations for different flow rates that would ascertain compliance with the standard. Equation 1 can be solved for constant flow rate, inlet concentration, and CO 2 production rate (Equation 3) for a given time period as in Equation 2.…”

Konsentrasi Co2 Pada Ruang Kelas Dengan Sistem Ventilasi Alami, Tipe Jendela Gantung Atas

“…Konsentrasi CO2 di dalam ruang kelas akan bertambah tergantung beberapa faktor antara lain jumlah dan aktivitas siswa, densitas atau tingkat kepadatan penghunian ruang, lama berada di dalam ruang serta jumlah udara segar yang masuk ke dalam ruang (ventilation rates). Mengurangi konsentrasi CO2 di dalam ruang kelas hanya dapat dilakukan dengan cara pengenceran yaitu melalui pertukaran udara atau memasukkan udara segar ke dalam ruang dengan memanfaatkan ventilasi yaitu ventilasi alami [13], ventilasi mekanis [10], atau menggabungkan keduanya [8].…”