Majeed Olaide Oladokun

Ventilation Performance Assessment of an Educational Building in a Hot and Humid Climate

Air Handling Units in mechanical ventilation system possess a high degree of potential to circulate contaminants within occupied spaces of a building which often results in sick building syndrome (SBS), building related illness (BRI) and other indoor air quality (IAQ) related issues. This happens despite the expected role of ventilation systems to create a balance of thermal comfort and indoor air quality to the building occupants as well as the stored components. In the hot and humid climate mechanical ventilation systems play an important role of controlling the indoor hygrothermal conditions. Inadequate performance of the mechanical ventilation systems result in several issues ranging from human occupants discomfort, mechanical damages to archival materials and mould problem amongst others. This study presents the measurement and analysis of the mechanical ventilation systems’ performance and its effect on various indoor spaces in an academic building in Malaysia. Measurement of airflow, thermal and hygric conditions of the facility together with the aero-biological sampling were executed. The ventilation performance assessment revealed that the AHU fails in its cooling and dehumidification capacities as most of the occupied zones witnessed elevated humidity and low temperature and hence poor hygrothermal performance. On the other hand, results of bio-aerosol assessment indicates that the AHU performs well in its decontamination capacities by reducing the microbial level between the AHU and the occupied zones. The dominant species of mould in the assessed spaces are Penicillium sp., Yeast, Cladosporium sp., and Chaetomium sp. with 100 % occurrence in all the assessed space. On the other hand, Black Mold, Syntalidium sp., and zygomycetes are the least species in spaces with 25 % occurrence. The presence of black mould portends a great danger to the occupants’ health and therefore requires urgent attention.

Response-surface-model-based system sizing for Nearly/Net zero energy buildings under uncertainty

Properly treating uncertainty is critical for robust system sizing of nearly/net zero energy buildings (ZEBs). To treat uncertainty, the conventional method conducts Monte Carlo simulations for thousands of possible design options, which inevitably leads to computation load that is heavy or even impossible to handle. In order to reduce the number of Monte Carlo simulations, this study proposes a response-surface-model-based system sizing method. The response surface models of design criteria (i.e., the annual energy match ratio, self-consumption ratio and initial investment) are established based on Monte Carlo simulations for 29 specific design points which are determined by Box-Behnken design. With the response surface models, the overall performances (i.e., the weighted performance of the design criteria) of all design options (i.e., sizing combinations of photovoltaic, wind turbine and electric storage) are evaluated, and the design option with the maximal overall performance is finally selected. Cases studies with 1331 design options have validated the proposed method for 10,000 randomly produced decision scenarios (i.e., users’ preferences to the design criteria). The results show that the established response surface models reasonably predict the design criteria with errors no greater than 3.5% at a cumulative probability of 95%. The proposed method reduces the number of Monte Carlos simulations by 97.8%, and robustly sorts out top 1.1% design options in expectation. With the largely reduced Monte Carlo simulations and high overall performance of the selected design option, the proposed method provides a practical and efficient means for system sizing of nearly/net ZEBs under uncertainty.

Influence of Indoor Microclimate Distribution on Mould Infestation in a University Library

Indoor mould contamination portends grave consequence to the stored components as well as inhabitants of infested dwellings. Such defilement, which is due to favourable growth environment for micro-organisms, is often associated with Sick Building Syndrome (SBS) and other Building Related Illness (BRI). As the economic development of Malaysia continues, increase numbers of air-tight, fully air conditioned buildings are evolving. Currently limited guidelines exists on Indoor Air Quality (IAQ) in Malaysia and its knowledge amongst the public is lacking. Hence, diagnosing the aggravating factors favouring indoor mould becomes beneficial as earlier detection is often difficult until growth has advanced. The study aimed at investigating mould infestation in a mechanically ventilated library building in Malaysia. Microclimate parameter and mould sampling were carried out. The microbial investigation results in 72 isolates whose distribution were 86 % mould, 13 % yeast and 1 % bacterial. It is found that Aspegillus sp. and Onychocola sp. were most common. The library internal microclimate distribution is characterised by uneven hygrothermal profile which results in high level of cellulolytic mould species that are highly detrimental to books and other archival materials. It is recommended that the HVAC system operations and set-points be critiqued to bring the ambient to the preservation requirements. In addition, load balancing for thermal and hygric distribution analysis should be executed to eliminate dead-spots in temperature and moisture distributions.