Solar Energy Perspectives - IEA

Chapter 4: Buildings
area is limited, as in densely populated areas. If larger proportions of solar energy are to be
captured in the future in and from building envelopes, PVT modules could become an
imperative, as the available space on buildings is limited. Another possible advantage of PVT
modules is that they could help make affordable the cooling of buildings at night through
radiative heat exchange with the sky.
Photo 4.7 An installation of solar PV and thermal collectors on the same roof
Source: SunEarth Inc.
Key point
Solar PV and thermal are both needed on positive energy buildings.
The most critical energy issue in the industrialised world is probably not to assess whether
new buildings will have a small net consumption or a small net production, but rather to
accelerate the use of renovation of the existing building stock to reduce consumption, and
re-roofing with solar technologies to increase energy production.
In the developing world, the energy balance of new buildings is much more important,
particularly in light of the weakness of centralised energy networks in many countries.
Passive cooling options for both new build and renovation are of primary importance.
Architects and real estate developers need to combine the use of modern materials and
knowledge with traditional know-how on making the most from the local environment
and resources. Building-adapted and building-integrated PV, and to some extent STE,
probably offer a considerable potential under sunny skies, as do solar water heaters.
Finally, solar cooking can usefully substitute for fossil fuels and inefficient biomass use.
A truly integrated approach would probably need to go one step further, and look closer
at building-integrated PV generation and the way it is being used, in particular in
conjunction with the emergence of electric and plug-in hybrid vehicles (as is further
considered in Chapter 5). One aspect that deserves consideration is the nature of the
current: alternating (AC) or direct (DC). Grid-integrated systems all have an inverter, which
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© OECD/IEA, 2011