Building energy conservation and indoor air quality assessment in a subtropical climate
Creators: name: Rahman, Mohammad
Mahbubur
Publisher: name: CQUniversity
Year: 2022
Subjects: subject: 90607 Power and Energy Systems Engineering (excl. Renewable Power)
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: The steady increase in growth of electrical energy consumption and demand for building in rapidly expanding towns, cities and industries exceeds the growth production of power being made available. Therefore, energy conservation measures are becoming an increasingly important issue in building which can help reduce energy consumption and demand while maintaining a satisfactory occupant environment. The Building energy simulation program is an important tool for evaluating the energy conservation measures of buildings and can predict the energy performance of existing or conceptual buildings. This study investigates and evaluates the impact various energy conservation measures (ECM) with an aims to reduce energy consumption while maintaining satisfactory thermal comfort and indoor air quality for existing office buildings in sub -tropical climate. The study is divided into four major parts. The first part consists of energy audit and analysis of existing buildings' heating, ventilating and air conditioning (HVAC) systems. The second part consists of building energy simulation and base model validation. The third part investigates alternative energy conservation measures for buildings without compromising thermal comfort, assessment of indoor air quality and contamination levels, and correlation between indoor and outdoor environmental parameters. The fourth part consists of a thermal energy storage system and its economic feasibility analysis as a demand side management strategy to achieve energy and demand savings goals. DesignBuilder, a unique graphic user interface program based on EnergyPlus simulation engine is used, to compare and evaluate several alternative energy conservation measures for a reference building (Information Technology Model Building) located in Rockhampton campus of CQUniversity. Energy conservation measures considered include variable air volume (VAV) systems instead of constant air volume (CAV), photo electric dimming daylighting control system instead of general lighting, and double glazed low emittance windows instead of single glazed windows. The most notable investigation is the thermal energy storage (TES) system with its economic feasibility for the above mentioned reference building. Evaluations of ECM show that energy savings of up to 25% can be achieved by using the VAV system alone instead of CAV system alone. Energy savings of up to 12% can be achieved by using more energy efficient lighting with a stepped dimming control strategy alone. By implementing all of these proposed ECM together, a minimum of 31% electric energy can be saved annually. Air born fungal spore (mould) concentration measured in this study, did not reach a level that would cause any concerns for occupants. The study has found that the full capacity chilled water TES strategy has a lower initial base date cost compared to all other alternative ECM strategies. The study revealed that ECM can be successfully applied to buildings located in hot and humid (sub -tropical) climates where high energy is required for air conditioning systems. As the weather becomes extreme in summer and mild in winter, it is strongly recommended that a VAV system can be considered as a retrofit option when renovation takes place in such climatic office buildings. The applications of double glazing, chilled water TES technology and daylighting as ECM are also highly recommended for similar climatic buildings.