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Assessment of window systems considering solar and thermal performance

Liaros, Evangelos Marios LU and Gergaud, Frank LU (2018) AEBM01 20181
Energy and Building Design
Abstract
The solar and thermal performance of window is subject to a wide range of parameters. To simulate the energy performance is therefore difficult, and limitations might occur depending on the complexity of each case. This study presents some of the current limitations related to the assessment of window considering solar and thermal performance into the policy framework (standards, regulations and certifications) and two dynamic thermal modelling (DTM) tools. It is observed that the regulations and certifications referred to various standards regarding the assessment of solar and thermal performance that could affect the results. The study concluded that for more complex constructions, the difference between the software resulted in bigger... (More)
The solar and thermal performance of window is subject to a wide range of parameters. To simulate the energy performance is therefore difficult, and limitations might occur depending on the complexity of each case. This study presents some of the current limitations related to the assessment of window considering solar and thermal performance into the policy framework (standards, regulations and certifications) and two dynamic thermal modelling (DTM) tools. It is observed that the regulations and certifications referred to various standards regarding the assessment of solar and thermal performance that could affect the results. The study concluded that for more complex constructions, the difference between the software resulted in bigger deviation among the simulation outputs. By investigating some of the limitations in the DTM tools, this study also provides possible warnings for the assessment of window. (Less)
Popular Abstract
Window systems play a primary role on the solar and thermal performance of the buildings. During the last few decades, the growing popularity and the major energy saving potentials of transparent constructions in office buildings, propelled a rapid and fascinating development of this type of constructions. With the increasing complexity of window constructions, the performance becomes difficult to assess resulting in noticeable divergence between results from dynamic simulations.
The study aimed to identify possible differences between software tools, as well as, relating them to possible causes. Despite the fact that a comparison to empirical data was not possible, examination of the current policies (standards, regulations and... (More)
Window systems play a primary role on the solar and thermal performance of the buildings. During the last few decades, the growing popularity and the major energy saving potentials of transparent constructions in office buildings, propelled a rapid and fascinating development of this type of constructions. With the increasing complexity of window constructions, the performance becomes difficult to assess resulting in noticeable divergence between results from dynamic simulations.
The study aimed to identify possible differences between software tools, as well as, relating them to possible causes. Despite the fact that a comparison to empirical data was not possible, examination of the current policies (standards, regulations and certifications) was deemed necessary, in order to correlate to the assumptions and limitations applied in real-world cases. The countries considered in terms of regulations and certifications were Sweden and the UK. The investigation of solar and thermal performance was carried out for five exemplary types of windows used in office buildings in the context of both steady-state calculations and Dynamic Thermal Simulations. The software tools used were WIS 3, IDA ICE and IES VE.
The comparison of the steady-state results indicated some minor differences between the software tools in terms of U-values and g-values. Even though the calculations were carried out according to the same standards, the limitations applied by each program in modelling the layers of the constructions (e.g. characteristics of gas used in the cavities) could possibly explain the differences noticed.
Proceeding further to Dynamic Thermal Simulations, the software tools demonstrated bigger differences. The use of shading made the divergence more evident, as its characteristics affected the overall performance of the system. The three indices examined, namely solar gains, heat transfer and inner surface temperature, proved to be adequate in describing the different approaches from the software tools. In spite of having access only to the formulas of one of the tools, the tests (including assumptions and hypothesis from the authors) resulted to a solid conclusion; the impact of solar radiation was not considered in the same way -as described in the relevant standard- in the two programs. This outcome was also reflected on the energy (heating, cooling) that the active systems (HVAC) would need to compensate for. Specifically, the deviation in energy need among the results, seemed to increase as the complexity (solar and thermal insulation) of the examined constructions increased.
Finally, the study, based on the findings, commented on the regulations and certifications being in use at the time of writing and proposed possible future work that could enhance the analysis of this intricate field. (Less)
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author
Liaros, Evangelos Marios LU and Gergaud, Frank LU
supervisor
organization
course
AEBM01 20181
year
type
H2 - Master's Degree (Two Years)
subject
keywords
window systems, solar energy, thermal transmittance, dynamic thermal modelling tools
language
English
id
8948376
date added to LUP
2018-06-14 11:32:59
date last changed
2018-06-14 11:32:59
@misc{8948376,
  abstract     = {The solar and thermal performance of window is subject to a wide range of parameters. To simulate the energy performance is therefore difficult, and limitations might occur depending on the complexity of each case. This study presents some of the current limitations related to the assessment of window considering solar and thermal performance into the policy framework (standards, regulations and certifications) and two dynamic thermal modelling (DTM) tools. It is observed that the regulations and certifications referred to various standards regarding the assessment of solar and thermal performance that could affect the results. The study concluded that for more complex constructions, the difference between the software resulted in bigger deviation among the simulation outputs. By investigating some of the limitations in the DTM tools, this study also provides possible warnings for the assessment of window.},
  author       = {Liaros, Evangelos Marios and Gergaud, Frank},
  keyword      = {window systems,solar energy,thermal transmittance,dynamic thermal modelling tools},
  language     = {eng},
  note         = {Student Paper},
  title        = {Assessment of window systems considering solar and thermal performance},
  year         = {2018},
}