Which are the real internal environmental conditions in the office building of the so called “glass-box” and which are the implications of such conditions in the well-being of the occupants? Which is the energy demand to acclimatize these glass boxes to make them habitable? In other words, how much energy is consumed to the provision of thermal and visual comfort in the glass building, in particular in those located in cities of warm climates such as São Paulo (city of high-altitude subtropical climate)?

In 1990, the discussions about the environmental performance and energy efficiency of buildings with glass facades acquired relevance in national and international scenarios. Today, 30 years later, the great majority of the stock of tall office buildings in Brazilian cities (as in many other countries around the world), follow the design pattern of the glass-box of the past century that is monolithic, hermetically sealed and depended of building systems of air-conditioning and artificial lighting for 100% of the occupational time, in which the occupants are ever more disconnected from the control of their own environmental conditions, in general.

In 1990, the discussions about the environmental performance and energy efficiency of buildings with glass facades acquired relevance in national and international scenarios. Today, 30 years later, the great majority of the stock of tall office buildings in Brazilian cities (as in many other countries around the world), follow the design pattern of the glass-box of the past century that is monolithic, hermetically sealed and depended of building systems of air-conditioning and artificial lighting for 100% of the occupational time, in which the occupants are ever more disconnected from the control of their own environmental conditions, in general.

In 1990, the discussions about the environmental performance and energy efficiency of buildings with glass facades acquired relevance in national and international scenarios. Today, 30 years later, the great majority of the stock of tall office buildings in Brazilian cities (as in many other countries around the world), follow the design pattern of the glass-box of the past century that is monolithic, hermetically sealed and depended of building systems of air-conditioning and artificial lighting for 100% of the occupational time, in which the occupants are ever more disconnected from the control of their own environmental conditions, in general.

Data gathered by Daniela Pereira (1) of a sample of office buildings built since the beginning of the years 2000 in São Paulo showed that approximately 65% of those are of rectangular form and have around 1,000 to 2,100 m2 of floor plate, with plan dimensions that can get up to 30 by 70 meters. The facades of reflective glass vary among blue, grey and green coloured glass, being designed to be sealed, in other words, without operable windows. We are looking to a production of buildings that do not reflect either the current expectations and human requirements of environmental quality, or the environmental and energy demands of the 21stcentury.

But why do we perpetuate an old-fashion model of the office building in big cities like São Paulo, as well as in the rest of the country and even in the global context? The answer to this question encompasses multiple factors. One of the them is the cost of energy that probably is not high enough to generate a true interest in architectural solutions that can have a real impact in the reduction of energy demand, such as the elaboration of form and façade to a good use of daylight, the return of the external shading and even the selective opening of window apertures for natural ventilation. In São Paulo, for example, 1 kWh costs R$ 0,51 (2), whilst in London in cost of energy is almost the double, going up to what would be approximately R$ 0,93/kWh (3). In Frankfurt, the cost is even higher, getting to the equivalent of R$ 1,70 for 1 kWh (4).

Another factor is the lack of thorough technical understanding of the environmental and energy performance of this building model as well as of how to do it better. Not less important is the power of image that is kept of the glass-box artificially climatized building as a symbol of commercial status.

In this way, which are the architectural and technological perspectives to the achievement of commercial tall buildings of better environmental and energy performance? What is the image of this new architecture? In other words, what changes in the design of the building of a better performance?

Another environmentally problematic aspect of the sealed buildings of the glass-box type is the dependency of cooling and ventilation mechanical systems during 100% of the occupational time, which makes the occupants´ environment more subjected to internal contaminants, posing direct consequences to health. The concern with air quality gains unprecedented importance in the world of the New Corona Virus pandemic. Give a great deal of attention to the issue of maintenance of ventilation mechanical systems is certainly a measure to be taken, but it does not eliminate the question upon the real need for such a dependence of these systems. It is worth remembering that in commercial buildings, the direct and indirect cost with occupants´ salaries is much more than the accumulated cost of design, construction, operation and maintenance of an office building (5). Research outcomes show that an increase of 0,1 a 2% to the productivity of users, as a result of improvement of the quality of work environments (6).

In the discussion about the indoor air quality, it is worth considering that the air-conditioning system reutilizes the internal air, adopting only a fraction of air intake from outside, that is to say that in common office environments there is never 100% of the so called “fresh air”. The recommendations for air changes given by the Brazilian norm NBR 16401 (7), which defines the design parameters for space cooling, follow those from Anvisa (8), that indicates the need for a minimum intake of 27 m3of external air per person per hour. Applying this criteria, the equivalent of approximately 10% of external air is achieved, whilst the remaining 90% are made of “recirculating” air.

The bigger the portion of air-changes, in other words, of the intake of external air in the air-conditioning system, more energy is consumed in the artificial cooling process. Parallel to that, it is worth mentioning that filters of the air-conditioning system do not retain viruses or gases, acting only in the control of particles. In this way, the design and operation of building systems of space cooling are faced with the dilemma between better air quality, of great importance in the context of viruses and other contaminants and associated with a bigger intake of fresh air, versus a more significant energy efficiency of the system. Together with the energetic issues, the polemic of air quality of air-conditioning systems raises once more questions regarding the uncritical use of such systems.

And which are the costs of the design project of this model of buildings? In general, we are talking of simplified and replicated projects, which are also cheap. The interest for better buildings is directly related to more elaborated design projects, with more technical knowledge and environmental assessments since the conceptual phase, but would this be so much more expensive than the common practice? Abroad, a research from Greg Kats (9) revealed that a sample of 170 “green” acclaimed buildings in the United States had an average construction cost of only 1,5% higher than their similar ones that were not conceived for a differentiated environmental performance.

The debate about energy demand and environmental quality in buildings is even more relevant when it is considered that the majority of recently existing buildings will last at least another 50 years and will face the future of climate change and the warm-up of the cities. As demonstrated by a series of studies (10), only opening Windows we will manage to lower significantly the energy consumption in commercial buildings, but for this purpose, it is necessary to reinvent the facades in order to minimize the solar gains and rethinking floor dimensions and special arrangements.

Despite the historical lack of general interest for better buildings, the combination of a wider understanding of the real performance of the glass-box building as well as about the environmental and economic advantages of better quality buildings, coupled with the associated technical possibilities, keeps the potential to wake-up all stakeholders involved in the building sector in Brazil and abroad to the realization of truthful new paradigms of environmental performance.

notes

NA – A série de oito artigos intitulada “O pobre desempenho ambiental dos escritórios por trás da caixa de vidro” conta com os seguintes colaboradores: Amanda Ferreira, Ana Paula Mendes Silveira, Aparecida Ghosn, Beatriz Nascimento e Souza, Bruna Luz, Carolina Leme, Claudia Ferrara Carunchio, Cristiano Sato, Eduardo Gasparelo Lima, Erica Mitie Umakoshi, Guilherme Reis Muri Cunha, Julia Galves, Karen Daiane dos Santos, Laís de Gusmão Coutinho, Larrisa Azevedo Luiz, Monica dos Santos Dolce Uzu, Nathalia Lorenzetti, Paula Lelis Rabelo Abala, Sheila Regina Sarra e Sylvia Tavares Segovia.

NE – This is the first in a series of eight articles on the topic of “environmental performance”. The complete series is as follows:

1
PEREIRA, Daniela Cardoso Laudares. Iluminação natural em edifícios de escritório: metodologia para a avaliação do desempenho luminoso. Tese de doutorado São Paulo, FAU USP, 2017 <https://bit.ly/34G1pnR>.

2
ENEL. Tarifa de Energia Elétrica <https://bit.ly/2Gczena>

3
UK POWER. Compare energy prices per kWh <https://bit.ly/2JiPOmx>.

4
THALMAN, Ellen; WEHRMANN, Benjamin. What German households pay for power. Clean Energy Wire, 24 jan. 2020 <https://bit.ly/34IkaXP>.

5
KATS, Greg; ALEVANTIS, Leon; BERMAN, Adam; MILLS, Evan; PERLMAN, Jeff. The costs and financial benefits of green buildings: a report to California’s sustainable building task force, 2003 <https://bit.ly/35OaR83>; WARGOCKI, Pawel; SEPPÄNEN, Olli. Indoor climate and productivity in offices. Bruxelas, REHVA Guidebook, 2006.

6
CLEMENTS-CROOME, Derek J. Creating the Productive Workplace. Spon-Routledge, 2000.

7
ABNT. ABNT NBR 16401: Instalações de ar-condicionado – Sistemas centrais e unitários. Parte 1: Projetos de instalações. Rio de Janeiro, Associação Brasileira de Normas Técnicas, 2008.

8
ANVISA – Associação Nacional de Vigilância Sanitária. Resolução-RE n. 09, de 16 de janeiro de 2003.

9
KATS, Greg; Greening our Built World: Costs, Benefits and Strategies. Washington DC, Island Press, 2010.

10
COTTA, João; VIEIRA, João Leal. Capítulo 3: O Desempenho Térmico de Ambientes de Trabalho nas cidades de São Paulo e Rio de Janeiro. In: GONÇALVES, Joana; BODE, Klaus (Editores). Edifício ambiental. São Paulo, Oficina de Textos, 2015, p. 81-102; GALVES, Julia. Contemporary Translucent Buildings in São Paulo. Dissertação em Architecture and Environmental Design. Londres, University of Westminster, 2019; GONÇALVES, Joana Carla Soares; MARCONDES-CAVALERI, Mônica Pereira. Capítulo 2: Ventilação Natural em Edifícios de Escritórios: Mito ou Realidade? In: GONÇALVES, Joana; BODE, Klaus (Editores). Edifício Ambiental. São Paulo, Oficina de Textos, 2015, p. 57-80.

about the authors

Joana Carla Soares Gonçalves é arquiteta e urbanista pela UFRJ, mestre em Environment and Energy pela AA School of Architecture, doutora e livre-docente pela FAU USP. Orientadora dos programas de pós-graduação Arquitetura e Urbanismo da FAU USP e Architecture and Environmental Design, School of Architecture and Cities, University of Westminster, Londres. Profa. da AA School of Architecture, Londres. Diretora da Associação PLEA.

Roberta C. Kronka Mülfarth é arquiteta e urbanista pela FAU USP, mestre pelo Programa Interdisciplinar de Pós-Graduação em Energia da USP, doutora e livre-docente pela FAU USP. Orientadora de pós-graduação em Arquitetura e Urbanismo da FAU USP e no Programa de Educação Continuada – PECE, no curso de especialização de Gestão em Cidades, junto a POLI USP. Vice-coordenadora do USP Cidades. Chefe do Departamento de Tecnologia da FAU USP.

Marcelo de Andrade Roméro é professor titular da FAU USP. Arquiteto e urbanista pela UBC, mestre, doutor e livre docente pela FAU USP, Pós-Doc pela CUNY (USA). Orientador e professor dos programas de pós-graduação da USP, do Instituto de Pesquisas Tecnológicas do Estado de São Paulo – IPT, da Universidade de Brasília, do Centro Universitário Belas Artes de São Paulo e da Peter the Great St. Petersburg Polytechnic University.

Ranny Loureiro Xavier Nascimento Michalskié engenheira mecânica pela UFRJ, mestre e doutora em engenharia mecânica pela COPPE-UFRJ. Professora doutora da FAU USP, onde atua como docente no ensino e na pesquisa, na graduação e na pós-graduação. Coordenadora da Regional São Paulo da Sociedade Brasileira de Acústica – Sobrac. Participa da elaboração de normas técnicas brasileiras em acústica da Associação Brasileira de Normas Técnicas – ABNT.

Alessandra Rodrigues Prata Shimomura é arquiteta e urbanista pela PUC-Campinas, mestre pela Unicamp e doutora pela FAU USP. Professora pela Faculdade de Arquitetura e Urbanismo e Orientadora do programa de pós-graduação em Arquitetura e Urbanismo da FAUUSP. Advisor no Student Branch ArchTech Labaut da ASHRAE e Membro do Comitê PLEA (Passive and Low Energy Architecture) Chapter Latin America and the Caribbean (PLEA-LAC).

Eduardo Pimentel Pizarro é arquiteto e urbanista, mestre e doutor pela FAU USP. Professor da Universidade São Judas. É embaixador do LafargeHolcim Awards e já desenvolveu pesquisa na Architectural Association Graduate School, em Londres, e na ETH, em Zurique. Ganhador de prêmios como o Jovem Cientista (Brasília, 2012) e o LafargeHolcim Forum Student Poster Competition (Detroit, 2016).

Monica Marcondes-Cavaleri é arquiteta e urbanista, doutora e pós-doutora pela FAU USP. mestre pela AA Graduate School, Londres. Há 15 anos é consultora e pesquisadora em desempenho ambiental e eficiência energética da arquitetura. Especialista no uso de ferramentas avançadas de simulação computacional em avaliações dinâmicas e integradas de desempenho ambiental e eficiência energética. Auditora AQUA-HQE.

Marcelo Mello é engenheiro civil pela Politécnica USP, arquiteto e urbanista pela FAU Mackenzie, Mestre em Sustainable Environmental Design pela Architectural Association School of Architecture, Londres, e doutor pela FAU USP. Trabalhou com consultoria em sustentabilidade no Centro de Tecnologia de Edificações – CTE, e hoje atua como Diretor na Arqio Arquitetura e Consultoria.

João Pinto de Oliveira Cottaé arquiteto pela PUC-Campinas, mestre em Sustainable Environmental Design pela AA School of Architecture, Londres, e doutorando pela FAU USP. Sócio do escritório Oliveira Cotta Arquitetura. Em seu portfólio destacam-se o novo centro de P&D da empresa Siemens na Ilha do fundão, no Rio de Janeiro e a ampliação da estação de metrô Santo Amaro.

Juliana Pellegrini L. Trigo é arquiteta e urbanista pela FAU Mackenzie, pós-graduanda no programa de Arquitetura e Urbanismo da FAU USP, com foco em processo de projeto de edifício de alta desempenho. President Elect ASHRAE Brasil Chapter 2021/2022 e diretora do escritório Studio Symbios. Com mais de 20 anos de atuação, obteve publicações e premiações em concursos nacionais e internacionais.