Building Integration of Solar Energy. A Multifunctional Approach

This thesis consists of two parts. The first part deals with building integrated
solar energy, mainly from an architectural point of view. It is based
on a literature review and discusses solar energy, the building as a system,
the concept building integration (definition, motives, criteria, examples)
and the relation between architecture and solar energy.
The second part presents a novel design of a concentrating, hybrid PV/T
system, which uses windows as the media in the integration of building
and solar energy system. It is placed inside a window or a glazed facade,
where the reflectors are used as moveable sunshades and internal insulation
when closed. Since the system is involved in the building's thermal
balance and daylight provision, the system is evaluated for its thermal
properties and for its daylight obstruction. Measurements show that the
window's U-value is reduced from 2.8 for the bare window to 1.2 W/m2K
with closed reflectors, and simulations indicate a strong redistribution of
the daylight with open reflector screens.
The active thermal and photovoltaic performance has been measured
for determining the concentrating system's optical efficiency. Long-term
measurements of the thermal performance were also made during the
summer of 2004. The results were used for creating models, simulating
the system's performance, concerning PV/T yield, passive heat gains and
thermal loss due to the varying optical performance and U-value of the
open or closed reflectors. The simulations were used to privde an indication
of a suitable control strategy, i.e. balance between open or closed mode of
the reflectors, in respect for a maximal amount of daylight. It was suggested
to generally keep the reflectors open at irradiance levels between 10 and
200 W/m2, which gives an open window 2800 hours of the year. This
control strategy leads to an annual yield of 164 kWh/m2 of active solar
heat and 50 kWh/m2 of photovoltaic electricity, window area. The annual
net thermal transfer through the Solar Window is -78 kWh/m2.