Energy Potential of the Environment

Edeltraud Haselsteiner

Sun houses

Hungarian architect Pierre Robert Sabady is considered one of the pioneers of solar architecture in Europe. In the 1970s, he published an article enumerating the “seven pillars of the bio-solar house” [1]. In the article, he uses his single-family bio-solar house Hälg in Lucerne, which he designed in 1977, to explain how buildings can be energetically optimised. With a trapezoidal ground plan, he references Socrates’ original concept (see p. 56). While the broader south side is generously glazed, the narrower north side, which accommodates secondary rooms, is practically windowless. The ground plan is organised so that the stairwell, cellar and attic form interior buffer zones, while a generous conservatory in front of the south facade represents an outer buffer zone or greenhouse (Fig. 1). This basic principle of solar architecture has remained unchanged through the present and is among the most efficient types of energy-conserving construction. Houses heated by the sun do better in terms of life cycle costs than comparative conventional buildings, and their global warming potential is lower than that of normal low-energy and passive houses [2].

Communal living project near Vienna

After the oil crisis of the 1970s and a massive rise in oil prices, energy-saving buildings and alternatives to oil as a heating fuel became a dominant theme, especially in the construction of single-family homes. In

1984, Georg W. Reinberg realised a communal living project that married the principles of solar architecture and demands for healthful building materials to a community resolved on codetermination. The form of these buildings, placed in a stacked arrangement along a narrow, long, southfacing slope, was based on the need to achieve large sun-exposed surfaces while minimising mutual shading (Fig. 2). The individual buildings themselves are subdivided into three thermal zones: Conservatories and large glazed surfaces to the south, a middle zone including the sanitary core designed for the highest temperatures, and storage rooms on the north side.

Direct solar gain house

In the early 1990s, the development of direct solar-gain houses (Fig. 1, p. 10) that had been begun by Andrea Rüedi with his experimental solar buildings in Trin made it possible to establish appropriately constructed and designed houses optimally oriented toward the sun and without the need

1 Section and floor plan, bio-solar house Hälg near Lucerne (CH) 1977, Pierre Robert Sabady

1 North-oriented buffer zone

2 South-oriented buffer zone/ conservatory

3 Warm air solar heating roof

4 Central hearths

5 Living room

6 Dining area

7 Kitchen

Low tech: Solar architecture, sustainable materials for conventional heating. The five-storey single structure in Zweisimmen follows in the tradition of this basic idea (Fig. 3). Its western facade is slightly twisted towards the south in order to gain longer sun exposure during the winter. The solid timber construction is combined with a timberconcrete composite ceiling and a rammed earth floor to provide the necessary mass for energy storage, while the stairwell serves as a buffer zone for the interior rooms on the north side. Adhesives and chemical additives were avoided entirely to ensure a healthy indoor environment. The solid tim- ber walls are joined with dowels, meaning that the building can be disassembled and its materials can be reutilised after deconstruction. Interior heat sources, in conjunction with the sun, suffice to keep the house at a comfortable temperature year-round. The building has neither central heating nor ventilation.

Residential building in Paris

The fact that solar architecture with passive components, based on an energetically optimised orientation and ground plan concept, can function in a densely built-up

3 a–b

Office and residence building, direct solar-gain house in Zweisimmen (CH)

2014, N11 Architekten

Low tech: Solid timber construction with no central heating

4 a–b

Residential building, Paris (FR) 2013, Babled Nouvet Reynaud Architectes

Low tech: Passive solar architecture, natural ventilation a urban environment even as social housing is demonstrated in a building by Babled Nouvet Reynaud Architectes in Paris (Fig. 4, p. 59). The double facade incorporating usable conservatories with living spaces arranged behind them faces south to benefit from solar irradiance. The conservatories function as climatic buffers; a fibre-reinforced concrete slab acting as a storage wall absorbs the radiative heat intensified by the outer pane and releases it later into the living spaces [3].

Active energy facades

Even though solar thermal energy and photovoltaics have by now made technically mature and affordable solutions for harvesting solar energy available, there have been repeated initiatives to utilise the vertical facade surfaces for energy generation as well. An active energy facade system developed by Rudolf Schwarzmayr controls the solar influx through moveable louvres on the facade (Fig. 5). These employ the solid walls directly to store energy and are therefore also well-suited for renovations, since they can be mounted onto pre-existing solid walls. During times of energy demand and solar irradiation, the louvres open automatically to allow the heat to penetrate into the wall. Depending on the temperature and weather, the function of the facade components can be expanded beyond energy generation to simultaneously include shading and cooling. A corresponding building prototype is currently being tested and evaluated [4]. As in other active energy systems such as solar thermal energy and photovoltaics, the issue of whether this can be classified as low tech is a question of definition. If the focus is predominantly on the longevity and robustness of the overall system, then the implementation of technological means must be viewed in those terms and in those of energy usage.

Passive solar energy facades

Phase change or viscoelastic materials, also called latent heat storage materials due to their properties, are able to store thermal energy during phase transitions, for example when changing from a solid to a liquid state, without themselves heating up. This has huge advantages for lightweight construction: Heat can be stored in significantly less mass and volume, since the storage capacity of these materials increases by multiples in the vicinity of their melting point. Architect Dietrich Schwarz developed a passive solar facade component with an integrated heat storage module based on salt hydrate crystals. The crystals absorb heat during the day and re-emit it into the interior as radiant heat when the room temperature drops. Anteriorly placed prismatic glass reflects the light of the high summer sun, but allows the rays through when the incident angle is small,

7 Natural ventilation schematic a wind-driven ventilation b thermal-lift-driven ventilation c ventilation via wind and thermal lift combined

8 Qaa reception hall in a house with a wind tower (malqaf) and a windcatcher (badgir)

9 Natural ventilation, water evaporation and thermal storage masses that cool termite mounds in hot climates as in winter. This passive solar architectural concept was employed, among other places, in a senior citizens’ residence in Domat-Ems (Fig. 6) and in the new Marché International office building near Winterthur [5].

Natural ventilation

The positive effects produced by the natural ventilation of indoor spaces, or airing out rooms by opening windows, are not merely environment and energy-related.

From the perspective of the residents, these actions are seen as a chance to make direct contact with nature or to satisfy their need for fresh air. The natural movement of the air comes from pressure differentials that result from temperature differences. As a consequence, natural ventilation can occur either through wind or through thermal lift (Fig. 7).

Using wind forces or natural air currents to ventilate and cool the interior spaces of buildings has a similarly ancient tradition as does solar architecture. In the Persian Gulf and in the regions of the Mediterranean, wind towers are among the hallmarks of classical architecture. Their ability to cool rooms makes them the precursors of air conditioners. Their function relies entirely on thermal lift, specifically on the fact that warm air rises, while the denser cold air sinks toward the ground. Ventilation openings, which can vary in design depending on the location and the wind conditions, “catch” the “cool breeze” skimming along the ground or coming from the sea and channel it through the building. During windless periods, the stack or chimney effect supplies the necessary air exchange: isierung_id3512.pdf?m=1646386494& (last accessed 03.05.2022)

Heat, which has been stored throughout the day in the solid walls, is emitted into the space and drawn upward. At the same time, fresh and cool air flows in through doors and windows to replace it. This principle of natural cooling is often supported by combining it with water evaporation. In such cases, air from the wind tower is channelled through a damp cellar or over water-filled basins. The water evaporates in the cool but dry air and cools it even further (Fig. 8). In the design of natural ventilation systems, an exact climatic and usage-specific analysis is therefore needed so that the prevailing local air current conditions are understood. It is now possible to use computer simulations to analyse airflow and its effects in response to various influencing factors. Natural ventilation requires a driving force which guides air currents through a building by pressure or suction. Pressure differentials produced at the building envelope by thermal lift and wind can provide this. The strength of the suction effect depends on the temperature difference and the effective height. For this reason, tall buildings are especially wellsuited to a ventilation concept that relies on thermal lift.

Over the course of evolution, nature has developed numerous methods for protection against heat and cold that can be useful in architecture, as well. The Trinervitermes termite colonies in Africa, for example, build mounds more than 30 m high and tunnel down to the groundwater (Fig. 9). By means of a clever ventilation system, the structure is naturally conditioned through water evaporation and the resulting evaporative cooling [6].

[7] Hülsmeier, Petzinka In: Detail 6/2001

Hülsmeier, Frank; Petzinka, Karl-Heinz: Sanierung der Gebäudehülle. In: Detail 6/2001, p. 1084–1094

[8] Bathen 2022

Bathen, Anette: “Kreative und gemeinschaftliche Kirchenumnutzungen | Urbane Produktion.ruhr“. On 11 January 2022 https://urbaneproduktion.ruhr/kreativeund-gemeinschaftliche-kirchenumnutzungen/ (last accessed 25.03.2022)

[9] Detail 5/2014

Fisch, Rainer: Kirchenumnutzung — sakral profan suboptimal. In: Detail 5/2014, p. 398–404

Renovation Strategies

[1] Wilke 2013

Wilke, Sibylle: Bauabfälle. Umweltbundesamt. Dessau-Roßlau 2013. www.umweltbundesamt.de/daten/ressourcen-abfall/verwertung-entsorgungausgewaehlter-abfallarten/bauabfaelle (last accessed 17.02.2021)

[2] Auer, Franke 2020

Auer, Thomas; Franke, Laura: Robuste Architektur. In: Bundesinstitut für Bau-, Stadt- und Raumforschung (eds.), Lowtech im Gebäudebereich: Technical symposium TU Berlin 17.05.2019, Publication series Zukunft Bauen: Forschung für die Praxis. Bundesinstitut für Bau-, Stadt- und Raumforschung (Federal Institute for Research on Building, Urban Affairs and Spatial Development). Bonn 2020, p. 40–52

Klinge 2020

Klinge, Andrea: Weniger Technik — mehr Gesundheit. In: Bundesinstitut für Bau-, Stadt- und Raumforschung (eds.): Lowtech im Gebäudebereich: Technical symposium TU Berlin 17.05.2019, Publication series Zukunft Bauen: Forschung für die Praxis. Bundesinstitut für Bau-, Stadt- und Raumforschung (Federal Institute for Research on Building, Urban Affairs and Spatial Development). Bonn 2020, p. 82 – 97

C Assessments

Low Tech in the Context of International Building Evaluation Systems and Standards

[1] Global Status Report 2017

UN Environment and International Energy Agency: Towards a zero-emission, efficient, and resilient buildings and construction sector. Global Status Report 2017; www.worldgbc.org/newsmedia/global-status-report-2017 (last accessed 02.02.2021)

[2] Brown et al. 2018

Brown, Martin et al.: Sustainability, Restorative to Regenerative. An exploration in progressing a paradigm shift in built environment thinking, from sustainability to restorative sustainability and on to regenerative sustainability. Published by COST Action CA16114 RESTORE, Vienna 2018. www.eurestore. eu/wp-content/uploads/2018/ 05/

RESTORE_booklet_print_END.pdf (last accessed 01.05.2021)

Cole 2012

Cole, Raymond J.: Regenerative design and development: current theory and practice. In: Building Research & Information, Vol. 40, No. 1, 2012, p. 1–6 doi:10.1080/09613218.2012.617516

Reed 2007

Reed, Bill: Shifting from ‘sustainability’ to regeneration. In: Building Research & Information Vol. 35, Nr. 6, 2007, p. 674–680 doi: 10.1080/09613210701475753

[3] Endres 2020

Endres, Elisabeth: Hightech versus Lowtech oder einfach nur robust?. In: Lowtech im Gebäudebereich: Technical symposium TU Berlin 17.05.2019. Bundesinstitut für Bau-, Stadt- und Raumforschung (Federal Institute for Research on Building, Urban Affairs and Spatial Development). Published by the Federal Institute for Research on Building, Urban Affairs and Spatial Development. As of January 2020. Bonn 2020, p. 74 – 81

[4] Daniels 2000

Daniels, Klaus: Low-Tech — Light-Tech — High-Tech. Building in the Information Age. 1st corrected edition. Basel et al. 2000, p. 218

[5] Haselsteiner et al. 2021

Haselsteiner, Edeltraud et al.: Drivers and Barriers Leading to a Successful Paradigm Shift toward Regenerative Neighborhoods. In: Sustainability, Vol. 13, No. 9, 2021, Art. No. 9, doi: 10.3390/su13095179

[6] Reed et al. 2009 https://ideas.repec.org/p/arz/wpaper/ eres2009_331.html (last accessed 02.03.2021)

Reed, Richard et al.: An International Comparison of International Sustainable Building Tools. European Real Estate Society (ERES), eres2009_331, Jan. 2009.

SBi, GXN 2018 Statens Byggeforskningsinstitut (SBi); GXN (eds.): Guide to sustainable building certifications. Copenhagen 2018

[7] Forsberg, de Souza 2021 Forsberg, Mara; de Souza, Clarice Bleil: Implementing Regenerative Standards in Politically Green Nordic Social Welfare States: Can Sweden Adopt the Living Building Challenge? In: Sustainability. Vol. 13, No. 2, 2021, Art. No. 2, doi: 10.3390/su13020738

[8] SBi, GXN 2018 (see note [6]) Berardi 2012 Berardi, Umberto: Sustainability Assessment in the Construction Sector: Rating Systems and Rated Buildings. In: Sustainable Development, Vol. 20, No. 6, 2012, p. 411–424 doi: https://doi.org/10.1002/sd.532

E STRATEGIES

[1] Sölkner et al. 2014 Sölkner, Petra Johanna et al. 2014.: Innovative Gebäudekonzepte im ökologischen und ökonomischen Vergleich über den Lebenszyklus. Publication series Berichte aus Energie- und Umweltforschung 51/2014, Vienna 2014 (last accessed 29.11.2021) https://nachhaltigwirtschaften.at/resources/hdz_pdf/ berichte/endbericht_1451_innovative_ gebaeudekonzepte. pdf?m=1469660917& [2] Rüdi, Watter, Schürch 2016

Rüdi, Andrea; Watter, Jörg; Schürch, Peter: Solararchitektur: Häuser mit solarem Direktgewinn. Zurich 2016

[3] Endres 2020

Endres, Elisabeth: Hightech versus Lowtech oder einfach nur robust? In: Lowtech im Gebäudebereich: Technical symposium TU Berlin 17.05.2019, 1st edition, as of January 2020, Bundesinstitut für Bau-, Stadt- und Raumforschung, eds. Bonn: Bundesinstitut für Bau-, Stadt- und Raumforschung, 2020, p. 74–81 [4] Endres 2019 pdf#page=289 (last accessed 30.09.2021)

Endres, Elisabeth: Parameters to Design Low-Tech Strategies. Presentation at the Powerskin Conference. Delft Jan. 2019 http://pure.tudelft.nl/ws/files/69585347 /679_3_679_3_10_20190325.

[5] Endres 2017

Endres, Elisabeth: Parameterstudie LowTech Bürogebäude. Technical University of Munich. Chair of Building Technology and Climate Responsive Design. Munich 2017, p. 60 https://docplayer.org/165733295Parameterstudie-low-tech-buerogebaeude.html (last accessed 30.09.2021)

[6] see Note [3], p. 80

[7] Krause, Leistner, Mehra 2020 Krause, Pia; Leistner, Philip; Mehra, Schew-Ram: Einsatz und Auswirkung von Vegetation bei autochthonen Bauten. In: Bauphysik 4/2020, p. 184–195 doi: 10.1002/bapi.202000015

[8] Oswalt 1994

Oswalt, Philipp: Wohltemperierte Architektur. Neue Techniken des energiesparenden Bauens. Heidelberg 1994, p. 55 [9] ibid. [10] ibid.

[11] Erber, Roßkopf-Nachbaur 2021 Erber, Sabine; Roßkopf-Nachbaur, Thomas: Low-Tech Gebäude. Prozess Planung Umsetzung. Commissioned by the Climate and Energy Committee / Environmental Commission of the International Lake Constance Conference IBK, Constance 2021 [12] ibid.

[13] Brown et al. 2018

Brown, Martin et al.: Sustainability, Restorative to Regenerative. An exploration in progressing a paradigm shift in built environment thinking, from sustainability to restorative sustainability and on to regenerative sustainability. COST Action CA16114 RESTORE. Vienna 2018