Towards displacing domestic air conditioning in KSA : an assessment of hybrid cooling strategies integrated with 'Fabric First'€™ passive design measures

  • Jamil Fareed J Hijazi

Student thesis: Doctoral Thesis

Abstract

Reducing energy use and CO2 emissions to curb global warming and climate change are the greatest challenges now facing mankind. The vast majority of energy generated from fossil fuels is burned to run vehicles, fuel power stations and cool or heat homes. Saudi Arabia, the world's largest producer and exporter of petroleum, currently consumes almost three times higher than the world average energy use and hence; ranked ninth among nations for CO2 emissions. Among all fossil energy consumers, residential buildings use almost half of the Saudi’s prime energy sources and are responsible for almost 50% of the emitted CO2. In such a hot climate region, air conditioning (AC) of dwellings is by far the major consumer representing 69% of domestic energy use and drives peak loading. Future projections predict a continuous increase in energy use as the majority of existing buildings are poorly designed for the prevailing climate, leading to excessive use of mechanical AC. Therefore, it is crucial for Saudi Arabia to consider a horizon where hydrocarbons are not the dominant energy resource. The adoption of energy efficiency measures and low carbon cooling strategies may have the potential to displace a substantial percentage of oil currently used to run conventional AC plants. Therefore, the current study investigates the viability of ‘fabric first’ intelligent architectural design measures, in combination with hybrid ground cooling pipes integrated with black-body radiant night cooling systems, with a specific purpose to displace AC systems and decrease the carbon footprint while sustaining year-round thermal comfort. The interrogation of this hypothesis was addressed in three stages. The first stage was to generate a baseline analysis of the thermo-physical and energy performance of a typical residential block in Jeddah. The second stage involved developing an alternative low energy cooling approach that could handle high ambient temperatures.The task involved designing ground pipe ventilation integrated with high emissivity blackbody radiator to displace AC systems. The design of such ‘hybrid’ system required a parametric analysis combined with testing prototypes in field trials to establish actual ground temperatures at various depths and black body emissivity ranges under different sky conditions. This hybrid system became the subject of numerical modelling and simulation using DesignBuilder software in conjunction with EnergyPlus simulation engine. The third stage was to assess the simulation results and validate the cooling efficiency and cost-effectiveness of the hybrid system compared to the baseline. The preliminary results of prototype thermal simulation and field trials suggest that ‘fabric first’ passive designs and measures (PDMs), combined with night hydronic radiant cooling (HRCS) and supply ventilation via ground pipes (GPCS), can negate the necessity for a standard AC system by displacing over 80% of cooling demand and lower the carbon footprint of a typical housing block by over 75%. Such passive and hybrid system applications also have a remarkably short payback period with energy savings offsetting the capital costs associated with building thermo-physical enhancement.
Date of Award1 Jul 2016
LanguageEnglish
Awarding Institution
  • University Of Strathclyde
SupervisorStirling Howieson (Supervisor) & Andrew Agapiou (Supervisor)

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