Search

We analyzed the effects of air leakage and other building characteristics on outdoor particle penetration in classrooms. The building characteristics including air leakage of 12 Korean schools were investigated, and onsite measurements were conducted to estimate the outdoor particle infiltration. The correlations among variables associated with air leakage and building characteristics and outdoor particle infiltration were analyzed using the Pearson correlation analysis and linear regression. The effective leakage area (ELA) of classrooms varied highly from 340.8–1566.9 cm2, and a significant disparity in the air leakage characteristics among the classrooms appeared. The results of onsite measurement revealed that the average ELA was larger in the corridor side with an ELAcorridor-side of 264.7 cm2 than in the outdoor side (ELAoutdoor-side of 93.1 cm2). Results of correlation analysis indicated a high correlation (r = 0.68~0.78, p-value &lt, 0.05) between the size resolved outdoor particle source (P × λ) and specific ELA. Particularly, a strong linear relation (R2 = 0.69~0.71) with specific ELAcorridor-side was seen. Results suggest that cracks between windows and doors in the corridor side considerably affect outdoor particle penetration. These results indicate the importance of improving the airtightness of not only the building envelope but also the inter-zonal walls for effectively reducing the outdoor particle infiltration into classrooms.

The energy efficiency improvements in existing buildings have become priority concerns of the European Union to encourage energy efficiency amongst residents and buildings as well as facility managers. The characterisation of the building stock plays an important role in the definition of energy renovation strategies. In Portugal, there are over 120,000 social housing flats. This paper focused on the holistic characterisation of a social housing neighbourhood concerning the “in situ” assessment of the indoor environmental conditions and thermal comfort over one year as well as air permeability tests of the flats and evaluation of the energy consumption. The hygrothermal monitoring campaign was carried out using thermo-hygrometer sensors to record the indoor air temperature and relative humidity of a large number of flats over a 12-month period. The airtightness of these flats was determined resourcing fan pressurisation test (blower door test). A relationship between the users’ modifications in the flats and their consequence over the air permeability was pursued and the importance of balconies and exhaust fans for the flats’ air permeability was discussed. The hygrothermal monitoring campaign of the case study was carried out, in order to assess the indoor thermal comfort according the ASHRAE 55 standard. The results show a significant discomfort rate, suggesting that the users are living in unhealthy environmental conditions and the issues that most contribute to the poor indoor environmental conditions that characterise this building stock. In addition, the energy, gas, and water consumption of the flats were collected, and a statistical analysis was performed. Correlations between the variables were observed and two clusters were identified. Cluster 1 includes the lower energy consumption flats, but no real impact on the thermal comfort was found as the entire dataset presented low indoor air temperatures.

Few houses have been built in the Spanish Mediterranean in accordance with the Passivhaus (PH) standard. This standard is adapted to the continental climates of Central Europe and thorough studies are necessary to apply this standard in Spain, especially in the summer. High relative air humidity levels in coastal areas and solar radiation levels of west-facing fa&ccedil, ades require adapted architectural designs, as well as greater control of air renewal and dehumidification. A priori, energy consumptions undergo big variations. In this study, the construction of a single-family house in the Spanish Levante was analysed. All enclosure layers were monitored using sensors of surface temperature, solar radiation, indoor and outdoor air temperature, relative humidity, and air speed. The thermal behaviour of the fa&ccedil, ade enclosure and air infiltration through the enclosure were examined using the blower door test and impacts on annual energy demand were quantified. Using simulation tools, improvements are proposed, and the results are compared with examples of PH housing in other geographical areas. The annual energy demand of PH housing was 69.19% below the usual value for buildings in the Mediterranean region. Very thick thermal insulation and low values of airtightness could be applied to the envelope, which would work very well in the winter. These technique solutions could provide optimal comfort conditions with a well-designed air conditioning system in summer and low energy consumption.

The purpose of this study was to evaluate outdoor PM2.5 infiltration into multifamily homes according to the building characteristics using regression models. Field test results from 23 multifamily homes were analyzed to investigate the infiltration factor and building characteristics including floor area, volume, outer surface area, building age, and airtightness. Correlation and regression analysis were then conducted to identify the building factor that is most strongly associated with the infiltration of outdoor PM2.5. The field tests revealed that the average PM2.5 infiltration factor was 0.71 (±0.19). The correlation analysis of the building characteristics and PM2.5 infiltration factor revealed that building airtightness metrics (ACH50, ELA/FA, and NL) had a statistically significant (p &lt, 0.05) positive correlation (r = 0.70, 0.69, and 0.68, respectively) with the infiltration factor. Following the correlation analysis, a regression model for predicting PM2.5 infiltration based on the ACH50 airtightness index was proposed. The study confirmed that the outdoor-origin PM2.5 concentration in highly leaky units could be up to 1.59 times higher than that in airtight units.

This study investigates indoor/outdoor relationships of airborne particles under controlled pressure difference across the building envelope in Korean multifamily apartments. On-site field experiments on 14 apartment housing units located in urban areas in Korea are conducted to measure the indoor/outdoor ratios of number concentrations of size-resolved particles (0.3&ndash, 0.5, 0.5&ndash, 1.0, 1.0&ndash, 3.0, 3.0&ndash, 5.0, 5.0&ndash, 10.0, &gt, 10.0 &mu, m). To set identical pressure difference conditions across the envelope of each housing unit for better comparison of I/O ratio results, and to examine the effect of pressure difference on the I/O relations, indoor&ndash, outdoor pressure difference was controlled at 10, 30, and 50 Pa using a blower door depressurization procedure. Simultaneously, the air leakage characteristics of housing units are measured using the typical blower door pressurization-depressurization test method to correlate air leakage data and I/O ratios. As expected, moderately airtight housing units (ACH50 &le, 4.4) show lower I/O ratios than average leaky housing units (ACH50 &gt, 4.4), still, the averaged I/O ratios of finer sized particles (0.3&ndash, 1.0, and 1.0&ndash, 3.0 &mu, m) in the moderately airtight housing units were 0.75, 0.59, and 0.61 at an I-O pressure difference of 50 Pa, and 0.62, 0.51, and 0.49 at 10 Pa. The study indicates that indoor residents in moderately airtight Korean multifamily housing units with relatively small envelope area can still be exposed to high concentrations of outdoor originated fine particles.

We studied 226 low-income households as a part of the Colorado Home Energy Efficiency and Respiratory Health (CHEER) study to investigate the relationship between energy-efficiency retrofits (EERs) specific to air sealing of residential building envelopes, annual average infiltration rates (AAIR), and qualitative indicators of &ldquo, healthy&rdquo, homes. Blower door tests quantified the leakage area in each home, which was used to estimate the AAIR. Walk-through inspections were used to record observations of air-sealing retrofits conducted as part of Colorado&rsquo, s Weatherization Assistance Program and indirect indicators of poor indoor environmental quality (IEQ) in the homes, such as visible mold or stains, visible dust on hard surfaces, vapor condensation on windows, dampness, and perceived air quality. Results showed that building characteristics like age and volume affected AAIR more significantly than air-sealing EERs. Among the air-sealing EERs, homes with the air-handler ductwork sealed and windows weather-stripped were found to have significantly lower AAIR compared to the homes without these features. Mold growth, wall stains, notably higher levels of dust, and unacceptable odor levels were more frequently reported in homes with higher AAIR, showing that leakier homes do not necessarily have better IEQ.