- Title
- The development of a comprehensive metric which characterises the thermal performance of complete buildings
- Creator
- Albatayneh, Aiman M. K.
- Relation
- University of Newcastle Research Higher Degree Thesis
- Resource Type
- thesis
- Date
- 2016
- Description
- Research Doctorate - Doctor of Philosophy (PhD)
- Description
- The growing demand for energy, energy supply security, climate change and ways to reduce greenhouse gases (GHG) have all played a significant role in the designing of new sustainable buildings. To design efficient sustainable buildings, the accuracy of a building’s thermal simulation will have direct implications on the prediction of the thermal performance of the building and the operational energy costs for the life of the building. Therefore, the output of any simulation should reflect the actual performance in order to save more building operating energy and reduce GHG emissions. The main purpose of this research is to verify the validity of a universal metric, proposed for the first time in this study, to characterise the thermal performance of complete buildings called the Adaptive Thermal Metric (ATM). This metric facilitates the assessment of the thermal performance of whole building envelopes which leads to more thermally efficient housing designs. Using the building’s internal air temperature the new method takes into consideration the various building materials, orientation, shading, occupant behaviour, weather at the site and the environment surrounding the building. The ATM uses temperature to assess the building’s thermal performance, thus differing from other widely accepted methods that are based on energy consumption. This research consists of three stages. In the first stage, the variations of the internal air temperature of four existing housing test modules (Cavity Brick (CB), Insulated Cavity Brick (InsCB), Insulated Brick Veneer (InsBV) and Insulated Reverse Brick Veneer (InsRBV)) are compared with CFD simulation results to determine the accuracy of the CFD simulation. Long period CFD simulations have typically faced some issues, such as long computing times and internal air temperature increases over time. After addressing these issues, the simulations were carried out for one year, using larger time steps (minimizing the computing time by more than 99% when compared to a 1 minute time step simulation) and with results with an average accuracy of 93% compared with the real data at any given time during the studied year. This is the first attempt to use CFD alone, without the assistance of any additional software to find the internal air temperatures of buildings over long periods. In the second stage of the research, two universal metrics using an adaptive thermal comfort range with 90% and 80% acceptability limits are developed (designated ATM90 and ATM80 respectively). There ATM’s account for the percentage of time over which the internal temperature of a building remains within the define comfort limits. The results of the characterisation of the thermal performances for both limits indicated that the best performing module was the InsCB, followed by the InsRBV, InsBV and CB modules, respectively. These results are consistent with the previous findings from University of Newcastle research on walling systems and the AccuRate building assessment tool used in Australia, and thus justify the possibility of using this metric as a new assessment tool to characterise the thermal performance of complete building. In the final stage of the research, appropriate ways to improve building energy design in order to reduce the amount of energy required to sustain thermal comfort are considered. This includes a feasibility study to find the best energy efficient design with the least cost. As a case study CFD simulations were carried out and the ATM determined for a complete house in a different climate zone. CFD simulations resulted in an average accuracy of 92% which is consistent with the previous CFD simulations for the housing test modules at the University of Newcastle. The ATM was able to reproduce the thermal performance of different housing types in different locations. This illustrates the possibility of using the ATM as a new universal metric which could be applied anywhere around the world. The results found in this research are promising and may facilitate the use of this metric as a new building assessment method to accurately predict the thermal performance of any building envelope. Since the occupants are able to use various strategies to control their perception of the internal conditions, the method also has the potential to reduce the amount of heating and cooling energy necessary to sustain thermal comfort.
- Subject
- building; thermal assessment; ATM; adaptive thermal comfort; CFD
- Identifier
- http://hdl.handle.net/1959.13/1312979
- Identifier
- uon:22503
- Rights
- Copyright 2016 Aiman M. K. Albatayneh
- Language
- eng
- Full Text
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