Browsing by Author "Al Mindeel, Thara'A Faisal Abdullah"

Now showing 1 - 1 of 1

Restricted
Toward a Mixed-Mode Cooling Approach in Residential Buildings of Saudi Arabia: Performance Assessment of Hybrid Ventilated Buildings
(Imam Abdulrahman Bin Faisal University, 2017) Al Mindeel, Thara'A Faisal Abdullah; Alshaibani, Khalid A
Electiciry consunption rates in Saudi Arabia are considered one of the highestworldwide. The use of electricity in residential buildings comprises more than half ofSaudi Arabia's national electricity consumption. This results to greater envircnmentaldamage since conventional AC systems consume up to 60oZ ofa tlpical house's energy.For this reason, a hybrid "mixed-mode" system is proposed as a ryay of loweringdependence on typical AC systems. The hybrid mixed-mode system relies mainly onnatural ventilation to deliver comfort and tum into to the other mode (i.e. mechanicalcooling) whenever acceptable levels of comfod could not be achieved by the natualventilation mode. Thus, the aim of this thesis is to verify the applicability andeffectiveness of this system in residential buildings of Dammam city. Applicability ofthe system will be tested in terms of its ability to deliver adequate levels of thermalcomfort and its ability to reduce energy consumption in these buildings. The tools usedfor investigation are all provided in a single software (i.e. DesignBuilder v5) which isselected to conduct the analysis. These tools are namely Dynamic Thermal Simulation(DTS) coupled with Airflow Network Models and Computational Fluid Dynamics (CFD)each ofwhich is responsible for evaluating a specific side oftie proposed system. For comparison purposes, a base case is fiIst identified and simulated to create a basis onwhich the proposed case is seen against. Featurcs of the prcposed hybrid system areidentified after a comprehensive exarination of codes, standards, comfort models,extemal and intemal CFD analysis ofthe building under study. The natual ventilationmode ofthe hybrid system comprises of simple strategies that rely mainly on upper andlower vents together with the regular operation of wirdows. After finalizing systemfeatues, comfofi and energy consumption issues are then analyzed and evaluated. Sincethe system is operated using setpoints (cooling, heating, and natural ventilation setpoints)that are assigned accoding to the adaptive model ofcomfort, achieving acceptable levelsof thermal comfort is inevitable if the system successfully f,rnctiofled as intended. Forfurther comfort investigation, the aveage indoor ah temperatue, temperaturedisributior, and the rate of ventilatiofl for comfort cooling are checked to ensue thatacceptable levels of comfort are delivered. The comlort analysis conducted vedfied theability ofthe system to maintain indoor comfort most ofthe time. Energy analysis is then canied out to calculate the amount of energy consumed by the proposed case andcompare it against the base case's consumption. Results of the analysis showedremarkable energy savings ofthe hybrid system with 30.5% ercrgy reduction a,,rd,42o/oless cooling loads. Heating load, on the otler hand, ievealed a slight inoease probablycaused by a large number of openings in the building's envelope. Still, this increase isminor when seen against the overall energy reduction. It is; thereforc, evident from theseresults that hybdd, mixed-mode systems are considered a feasible approach to cooling inresidential buitdings of Dammam city.
11 0