The most popular PV technologies today on the market are crystalline and thin-film products. Although there are many other technologies in constant improvement.

In this architecture-oriented research, is not useful to classify BIPV systems regarding its PV technology, due to this continuous progress. This is why we have considered architectural features in order to classify façade BIPV systems. According to BIPV architectural features, façade systems have been classified in three groups:

BIPV System X: ‘Opaque’ consists of BIPV systems which we cannot see through. These BIPV systems can be installed as a regular façade coating to protect the thermal insulation and the building from weather and exterior agents.

BIPV Sytem Y: ‘Translucent’ is a semi-opaque or translucent surface, where we cannot see through, or there is some visual obstacle. It can be used for solar control purposes.

BIPV System Z: ‘Transparent’ consists in an almost transparent PV surface where we can see through with no visual obstacle. These systems fit in windows and other surfaces where visibility is required.

ANALYSIS

INTEGRATED DESIGN

Architectural Integration of Low-Carbon Technology and Building-Integrated Photovoltaics (BIPV):

Into the design process of Advanced Active Façades (AAF)Angela Clua Longas *1, Sophie Lufkin 1, Emmanuel Rey 1

* Contact: Angela Clua Longas angela.clualongas@epfl.ch

1 Laboratory of Architecture and Sustainable Technologies (LAST) Ecole Polytechnique Fédérale de Lausanne (EPFL)

AcknowledgementsThis research project is part of the National Research Programme “Energy Turnaround” (NRP 70) of the Swiss National Science Foundation (SNSF). Further information on the National Research Programme can be found at www.nrp70.ch. The authors also thank the Ecole polytechnique fédérale de Lausanne (EPFL) for its support.

15th National Photovoltaic Congress 2017 | SwissTech Convention Center, Lausanne, March 23-24

This research is part of the research project:

PV 2050 - Photovoltaics into the built environment: fromsemi-transparentPVglazingtohighefficiencyroof integrated solutions

In collaboration with:

THE ADVANCED ACTIVE FAÇADE (AAF) CONCEPTThese analysis have driven the research to develop the Advanced Active Façade Concept. Firstly, the AAF design responds to the common practice of façade composition today. Secondly, it meets the latest façade requirements, based on a low-embodied carbon construction, adapted to the most exigent insulating targets (Minergie P). Thirdly, it is an active element that generates energy thanks to the integration of BIPV systems in the façade composition. The AAF has been designed as a non-structural, self-supporting façade, which guarantees more flexibility in its design than other loadbearing proposals. Based on this concept, this research has developed the AAF Construction System and the AAF Design Strategies.

CONCLUSIONSAs it is an on-going process, the preliminary conclusions of this research permit to affirm that it is possible to integrate a BIPV system in a prefabricated construction system, based on current façade construction requirements and applicable to residential buildings. The developed work also demonstrates that BIPV can be part of the dimensional composition of a collective residential housing façade. This is to say, with the AAF Design strategies provided, architects can control BIPV expressive issues and produce façades which fit in the current composition trends in the Swiss context.The next steps involve: the assessment phase, where the environmental impact, cost, architectural quality and social acceptance will be evaluated; a prototype construction and a student competition, where the theoretical knowledge will be applied to the professional practice.The output of the research will provide architects with a system and assessed design strategies to optimize the design process of BIPV façades. Our objective is that architects, and society in general, find PV technology as a familiar construction material.

The results of this analysis have highlighted the latest façade requirements, which are :

a) Minimize the building’s energy consumption

b) To account with little embodied carbon.

c) To generate energy as part of the envelope

solution.

Nowadays, there are façades that meet one or two of the mentioned requirements, but very few which meet the three of them.

The whole trajectrory analysis is represented in the following chart

OPAQUE SEMI-OPAQUETRANSLUCENT

TRANSPARENT

BIPV SYSTEM A BIPV SYSTEM B BIPV SYSTEM C

OPAQUE SEMI-OPAQUETRANSLUCENT

TRANSPARENT

BIPV SYSTEM A BIPV SYSTEM B BIPV SYSTEM C

OPAQUE SEMI-OPAQUETRANSLUCENT

TRANSPARENT

BIPV SYSTEM A BIPV SYSTEM B BIPV SYSTEM C

OPAQUE SEMI-OPAQUETRANSLUCENT

TRANSPARENT

BIPV SYSTEM A BIPV SYSTEM B BIPV SYSTEM C

Analysis and classification of the existing façade design strategies of collective residential buildings in the current Swiss context.

This classification depends on the dimensional composition of façade materials, elements and building’s general structure.

Analysis of the façade requirements and systems trajectory.

This chapter explores the design principles of façades in a fundamental manner. It does not focus on specific façade variants or materials; rather it explores basic façade systems which meet the different façade requirements that have evolved through history. The goal is to define the present and near future façade requirements, to design a façade construction system that meets them.

Analysis and classification of the existing BIPV systems, regarding architectural requisites

AAF construction system.

It is a plywood-based, self-supporting and demountable façade system which meets the most demanding insulating targets and is compatible with a wide range of existing BIPV formats and emerging technologies.

The AAF construction system enables architects to play with a range of expressive parameters such as transparency and colour. This prefabricated system meets also the collective residential buildings’ design trends studied in phase 1A and developed in phase 2B. Therefore, suitable for a rapid and solid construction in the Swiss context.

Its main features are:

Low embodied carbon Wood frame Natural insulation: cellulose Minimized metallic elements. Choose recycled Aluminium Use of local materials No synthetic Vapour Barrier Prefabrication Low maintenance design Easy component replacement Light construction Recyclable system Designed to be disassembled

Active Façade Building Integrated Photovoltaics Ventilated façade Punctual fixation Wiring design Orientation study Energy production targets

AAF CONSTRUCTION SYSTEMConstruction Detail.

ADVANCED PRACTICEPASSIVHAUS

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AAF CONSTRUCTION SYSTEMDECOMPOSED AXONOMETRIC VIEW

AAF design strategies.

They are a series of design strategies derived from the existing ones combined with the three categories of BIPV products identified. These designs are applied to a real site and the design process permits the enumeration of a series of guidelines to successfully design an Advanced Active Façade.

Here are gathered four images which represent the combination of the existing design strategies identified in phase 1A: “Slab to Slab”(1), “ Total Storey”(2), “Balconies”(3) and “Total Volume” (4). With the three BIPV Systems identified in phase 1C: “Opaque”(X), “Translucent”(Y), “Transparent”(Z). These façade design strategies meet the requirements analysed in phase 1B, and can be constructed with the AAF Construction System.

PROTECTION FROM THE ENVIRONMENT

LOADBEARING

PROVIDE VENTILATION

PROVIDE LIGHT

THERMAL INSULATION

PROTECTION FROM THE SUN

ACOUSTIC INSULATION

LOWER ENERGY CONSUMPTION

LOWER EMBODIED ENERGY

GENERATE ENERGY

PROVIDE VIEWS

REQUIREMENTS

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INDUSTRIAL REVOLUTION 1st OIL CRISIS ENERGY STRATEGY 2050S. XIX 1976 2011

RESIDENTIALFAÇADEREQUIREMENTSAND SYSTEMSTRAJECTORY

PROTECTION COMFORT SUSTAINABILITY

OVERVIEW

1. ANALYSIS

2. DESIGN

1A. Existing façade strategies

Analysis and classification of theexisting façade design strategies

1 2 3 4

2A. Construction System

Design of the Advanced Active Façade (AAF) Construction System

3. ASSESSMENT

Environmental impact/ Cost/ Architectural quality/ Social acceptance

4. PROTOTYPE

Construction of a prototype (scale 1:1) of an AAF element

5. STUDENT COMPETITION

Real site application and building analysis

2B. Design Strategies

Development of the AAF Design Strategies combining the previous data csith the CS

1B. Façade requirements

Analysis of the façade requirements and systems trajectory

Low-carbon

1C. BIPV technologies

Analysis and classification of existing BIPV systems regarding architectural requisites

A B C

RESEARCH METHODOLOGY

Building Integrated Photovoltaics’ (BIPV) performance is improving rapidly. However, their potential is diminished because of several barriers. Due to its limited expressive quality, architects tend to avoid integrating BIPV in building design, more particularly, in façades. In order to bridge the gap between technology and design, this research aims at developing design strategies to integrate BIPV’s expressive issues into today’s façade construction, focusing on new collective residential dwellings.

In this context, the poster presents the Advanced Active Façade (AAF) concept, which results from the analysis of façade’s evolution, in terms of requirements and constructive solutions. The AAF benefits from passive low-carbon design strategies and active BIPV technology.

This system permits to meet low energy consumption targets and, by integrating BIPV expressive issues, it enables architects to play with a range of expressive parameters such as transparency, color and modulation.

AAF CONSTRUCTION SYSTEMDETAIL1_20

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24 2,77

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AAF CONSTRUCTION SYSTEMConstruction Detail.1_10

2345

78

1

9

1110

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2- Metallic punctual invisible fixation / gap for PV rear ventilation 100 mm3- Tripli panel 27mm4- Wood fiber insulation 240 mm / Triple plywood panel 240 mm5- Triple plywood panel 27 mm

1- PV panel

6- Optional interior cellullose insulation 50 mm7- OSB panel8- Interior coating9- Triple plywood panel 27 mm10- Exterior stores for sun control11- Neopren joint (search for "sustainable" equivalent)12- Insulation13- Wood window frame

6

1124

240

1 10 2,7 511

40,447,4

24 2,77

240

AAF CONSTRUCTION SYSTEMConstruction Detail.1_10

2345

78

1

9

1110

1213

2- Metallic punctual invisible fixation / gap for PV rear ventilation 100 mm3- Tripli panel 27mm4- Wood fiber insulation 240 mm / Triple plywood panel 240 mm5- Triple plywood panel 27 mm

1- PV panel

6- Optional interior cellullose insulation 50 mm7- OSB panel8- Interior coating9- Triple plywood panel 27 mm10- Exterior stores for sun control11- Neopren joint (search for "sustainable" equivalent)12- Insulation13- Wood window frame

6

The results provided by this research present a façade classification in four groups:

Strategy 1: ‘Slab to slab’, includes those façades where the horizontal slab dimension is apparent and highlighted on the façade.

Strategy 2: ‘Total storey’, involves those façades where the storey structure is also evidenced but the floor slabs are no longer highlighted.

Strategy 3: ‘Balconies’, refers to those facades where the balconies are clearly apparent in a large part of the façade.

Strategy 4: ‘Total volume’, includes those façades where the structure rhythm and the interior distribution is not apparent.

2Y

1X

3Z

4X