Parametric Analysis of Natural Air Exchange in Multi-Apartment Residential Buildings

Abstract

Most multi-apartment residential buildings built in the 20th century in Central and Eastern Europe do not meet modern energy efficiency requirements. The main part of the thermal energy consumed by buildings is used to heat the supply air from outside, which is the largest share in the energy balance of buildings. The purpose of this research is a parametric analysis of influencing factors on the frequency of air exchange in the room and an experimental study of the concentration of CO2 in a typical apartment. The object of the study is a one-room apartment in a family-type dormitory in the city of Kyiv. The dormitory has ducted natural ventilation. In the work, experimental measurements of the concentration of carbon dioxide were carried out in the premises of the living room, kitchen, corridor of the apartment and in the ventilation channel in the summer period. The indicator gas method was used to measure the air exchange rate. During air infiltration, the average rate of air exchange in the absence of people in the apartment in the living room was 2.41 h-1, in the corridor - 2.34 h-1, in the kitchen - 0.57 h-1. Under exfiltration conditions, the average values were lower: living room – 0.24 h-1, corridor – 0.94 h-1, kitchen – 0.52 h-1. The dependence between wind directions and the phenomena of infiltration and exfiltration in the premises of the apartment was recorded. As a result of the research, it was established that the most influential parameter of the change in the concentration of CO2 in the room is the release from people's breath. It follows from the simulation results that to ensure the regulatory level of CO2 concentration is not higher 1500 ppm, it is necessary to observe the air exchange in the considered room not lower than the level of 1.51 h-1 for conditions when 2 people are constantly in the room That is, the mass balance of CO2, which takes into account the number of inhabitants, can be an attractive alternative method for predicting the intensity of ventilation of a building.