Abstract
Traditionally the majority of energy used in buildings has been linked to theiroperation (heating, cooling, lighting, etc). Much attention has been directed to
assess and reduce this energy use. As it is progressively reduced through
design, technical innovation and regulatory control, buildings often employ an
increasing amount of materials and systems, to the point that their associated
embodied energy can constitute an important part of the building’s life cycle
energy use. For buildings with ‘zero-energy’ use in operation the embodied
energy is indeed the only life cycle energy use. Despite this, current building
energy assessment and rating methods, and definitions for ‘net zero energy
buildings’ or ‘nearly zero energy buildings’, frequently ignore the embodied
energy component of building life cycle energy use.
The aim of this thesis was to develop a methodology to evaluate life cycle
energy performance of buildings, including embodied energy of the different
components and systems, which could be integrated with building energy
assessment and rating methods. The developed methodology serves to define
‘Life Cycle Zero Energy Buildings’ (LC-ZEBs) as those whose primary energy
use in operation plus the energy embedded in materials, components and
systems over the life of the building is equal or less than the energy produced
by renewable energy systems within the building. The methodology relies on
the use of energy evaluation methods and on embodied energy calculations,
simplified through various approaches described in this thesis. The application
of the methodology to the development of a Life Cycle Building Energy Ratings
(LC-BER) is also presented.
The life cycle energy evaluation methodology is further investigated with the
integration of occupant’s behaviour and comfort expectations, demonstrating
the potential contribution of these aspects not only in the energy use of
buildings in operation, but also the embodied energy associated with
equipment and systems.
This thesis also introduces the concept of ‘Net Energy Ratio’ to the built
environment, presenting it as an indicator to support building design
optimization from a life cycle energy perspective. Net energy ratio is calculated
in detail for a specific technology such as domestic solar water heating,
demonstrating their good life cycle energy performance when compared with
other building design strategies or renewable energy systems. The study also
provided an insight to the problems associated with solar water heating
systems operation, which can worsen their life cycle energy performance.
The developed life cycle energy evaluation methodology is integrated within
various calculation methods and tools, and applied to multiple building case
studies, illustrating its practical use and demonstrating the importance of life
cycle energy evaluation, particularly for domestic buildings with low energy
use in operation, in a maritime climate.
| Date of Award | 2011 |
|---|---|
| Original language | English |
| Awarding Institution |
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