P h o t o v o l t a i c s a n d ( N e a r l y ) N e t Z e r o E n e r g y B u i l d i n g s
301
PHOTOVOLTAICS AND (NEARLY) NET ZERO ENERGY
BUILDINGS: ARCHITECTURAL CONSIDERATIONS
Alessandra Scognamiglio
1
, Eike Musall
2
& Harald N. Røstvik
3
1
Photovoltaic Technologies Area, Portici Technological Unit, ENEA, Italy
2
Department of Architecture, Bergische Universität Wuppertal, Germany
3
Sivilarkitekt MNAL Røstvik AS / Bergen School of Architecture, Norway
Abstract
The energy topic has become increasingly important in architecture: since buildings are
big consumers of energy and architects and the public are interested in energy as never
before. [Scognamiglio 2008] The Energy Performance of Building Directive (EPBD) [EU
2010] establishes that starting from 31
st
December 2020 all new buildings have to be
Nearly Zero Energy.
The main architectural implication for this condition is that if up until now the domain of
design was the building itself, now it is the building and possibly other spaces, that have
to be conceived for placing the energy generation devices. Photovoltaics (PV) is
particularly suited for reaching the (Nearly) Net ZEB status, due to its technical features,
the existing knowledge on how to use PV in buildings, and since it is the easiest and
most reliable way to get the (Nearly) Net Zero Energy objectives. [Torcellini 2006]
A relevant international effort on the subject of the Net Zero Energy Buildings (Net ZEBs)
- Net ZEB meaning that the buildings are connected to an energy infrastructure - is
ongoing in the International Energy Agency (IEA), joint Solar Heating and Cooling (SHC)
Task 40 and Energy Conservation in Buildings and Community Systems (ECBCS)
Annex 52, titled “Towards Net Zero Energy Solar Buildings” [IEA 2008a].
The authors of this paper, all participating in the IEA research group, investigate how the
use of PV for Net ZEBs can influence the building’s design, taking into account different
building typologies (e. g. new ones vs. existing ones, listed buildings, etc.). Similarities
and differences between PV and Solar Thermal (ST) are discussed, too. The paper
results in defining some architectural issues for using PV in NZEBs design, which implie
to re-think the way buildings are designed.
Keywords:
(Nearly) Net Zero Energy Building, Architecture, Photovoltaics, Listed
buildings, Cities and energy self sufficiency.
Introduction and background
The recast of the EPBD establishes that starting from the 31
st
of December 2020 all new
buildings have to be Nearly Zero Energy Buildings. According to this Directive, Nearly
Zero-Energy Building means a building that has a very low energy yearly energy
consumption, which can be achieved by both highest energy efficiency and by energy
from renewable sources, which shall be on-site or nearby [EU 2010].
In a near future, buildings will be designed to need very little energy (due to passive
design strategies and high energy efficiency), and to integrate active surfaces (e.g. PV
modules) for generating energy. As a consequence, design has to consider not only the
floor area we use directly, but also the space required to provide for electrical and
thermal energy from renewable sources: the surface necessary for placing the energy
generation devices. This area can be defined as the “building’s energy footprint”, and it
will have to be considered in the domain of design.
As will show, designing the buildings and their energy footprint is the big challenge that
architects and designers have to face in the future. The way this challenge will be taken
up will influence a lot our habitats, cities and landscapes of tomorrow. [Scognamiglio,
Ossenbrink, Annunziato, 2011]
