An experience on applying sustainability and energy

efficiency in undergraduate building design

Roberta Vieira Gonçalves de Souza Dra, Teacher of Departament of Technology, robertavgs2@gmail.com. Universidade Federal de Minas

Gerais, Laboratory of Environmental Comfort, Belo Horizonte - MG, 30130-140, Tel.: (31) 3409-8872

Ana Carolina de Oliveira Veloso Architect, Master student of the Post Graduation Program in Building Environment and Sustainable

Heritage of the Universidade Federal de Minas Gerais, acoveloso@gmail.com.

Paula Rocha Leite Architect, student of the Specialization Course of Technological Systems and Sustainability Applied to the

Built Environment of the Universidade Federal de Minas Gerais, papaular@yahoo.com.br.

ABSTRACT

Contemporary buildings, as a general rule, have a responsibility in the increasing global

warming and environment degradation, mainly through the intensive use of energy, and

resources consumption. And therefore they can be seen as having a great potential in the

mitigation of those problems they help create. According to environmental researches, there is

an urgent need for the society to change its behavior, diminishing the production of waste,

minimizing the use of resources and energy and enhancing the efficiency of its processes.

Issues like daylighting, natural ventilation, sun protection, environmental comfort and energy

efficiency must be addressed in the first stages of the building design in order to generate

sustainable and efficient buildings.

In the specific context of energy efficiency in Brazil, it was launched on July 2009 the

National Energy Conservation Label (ENCE) for Commercial, Service and Public Buildings.

The evaluation is valid for conditioned, partly conditioned and non conditioned existing or new

buildings.

The School of Architecture of the Federal University of Minas Gerais, Brazil is already

training its students to be able to face this new regulation and the design needs that are attached

to the certification process, in order to enhance not only the energy efficiency of building but

also their sustainability. The present paper shows two final graduation designs (TFG) made by

students, based on concepts such as flexibility, environmental comfort, energy efficiency,

resource conservation, and discusses the effort needed and the necessary changes in the

conception process in order to fulfill these new needs in the design process.

One of the studies was the refurbishment of a building transformed in a convention center

in Formiga (Minas Gerais), which was classified according to the new ENCE requirements. The

other one is a sustainable housing of mixed use (residential and commercial) in Nova Lima, also

in Minas Gerais. The design studies show the commitment of a new generation of architects to

the principles of sustainable architecture and also to a more sustainable way of living.

1- INTRODUCTION

Buildings, over the last decades, have strongly contributed to the environmental

degradation by a large usage rate of energy, though they may also present a potentially

reasonable alternative for damage reduction. In order to achieve it, the likes of environmental

comfort, energy efficiency and water consumption decrease must be taken into account from the

beginning of the architectonic project, as means to develop an integrated process of building

conception which leads to a low environmental impact.

In view of these parameters, two Completion of Course Works were developed – both

considering, in its conception, the application of climatic variables for the purpose of energy

efficiency, being later on detailed, thus enabling the refinement of decisions and specifications.

The evaluation presented high rating levels on commercial building and, if the same

rules were applied to the residential rating, the results wouldn’t differ much. This was made

possible through previous consideration of climatic aspects, as the course of the article will

show. The results obtained allowed both works to take part in national architecture contests, as

one of them recently won the National Award for the Conservation and Rational Use of Energy

(ELETROBRAS/CONPET).

2- PROJECT DESCRIPTION & METHODOLOGY

The first work concerns the design of a Cultural Center in Formiga, Brazil. The

development of this project aims relocating schools to the former city foundry, which is

currently abandoned. This is a refurbishment project, which not only looks towards the recovery

of a historic building, but also attempts to provide a better infra-structure for the site, so it may

be able to admit over 900 students, teachers and visitors.

The second work consists in developing a 30.930 m² housing condominium at Nova

Lima, Brazil. Through the use of natural lighting and ventilation as well as many other

bioclimatic strategies, the project suggests a reduction in the energy consumption for apartments

and public spaces (such as lobbies and garages). Besides presenting an alternative to reduce the

environmental impact, this work provides solutions to both operational costs and user

productivity and comfort. In addition, as the residential buildings should be connected to a

commercial office building, it shortens users’ traveling time through places.

PICTURE 01: External Perspective of the Cultural Center

FIGURE 02: Internal Perspective of the Cultural Center

PICTURE 03: Residential Bulding PICTURE 04: Resource Usage Diagram

3- DEVELOPMENT

Not only as a tendency, but also as a need, the global process of implementation of

building standards concerning energy efficiency has gained more adepts. In Brazil, this project

is yet incipient, and the studies looked towards an integration of bioclimatic strategies from its

conception, in order to decrease the need of using energy operating systems.

3.1 - STANDARDS

The Brazilian electric energy sector has one of the biggest hydroelectric parks of the

world, corresponding to 82.36% of all electric energy produced within the country. This is only

possible because of its hydrographical basin which, besides its extension, has great capability as

to generating electric energy. Until the mid 90’s this system was able to attend the country’s

demand, however insufficient investments in the sector allied to political/economic issues, to a

low rain rate and to an increasing energy consumption led the hydroelectric energy supply to

give shortage signals. This process ended up in 2001 when the country was forced to implement

energy rationing – a watershed in Brazilian electric sector –, which served as a route for new

long term investments, thus extinguishing further rationing risks.

Later on, as seen on Europe and North America, measures concerning electric energy

usage were adopted by the Brazilian government. The law 10295/2001 states that “the

maximum level of energy consumption or minimum of energy efficiency, of energy consuming

machines and equipment manufactured or commercialized in the country, as well as

constructions shall be pursuant to technical indicators and specific regulations”, which are

defined in the decree. In order to implement these specifications, PROCEL – Electric Energy

Conservation Program approved the RTQ-C – Technical Quality Standards for the Energy

Efficiency of Commercial, Service and Public Buildings in 2009, while the Residential Building

Standards shall be implemented in 2010.

RTQ-C building evaluation is divided into four unequally weighted sections, as follows:

building envelope (30%), lighting (30%), air conditioning (40%) and the building as a whole;

which are classified through rates from A – more efficient to E – less efficient. The evaluation is

made either by a simplified prescriptive method or by building computer-aided simulation,

enabling the evaluated building to receive an ENCE – National Energy Conservation Label,

indicating the building’s overall performance and also its performance on each section.

In opposition to other countries – where such measure was originally directed to the

residential sector, the first set of parameters to be developed in Brazil was the RTQ-C. This is

due to a growing range of diverging features among residential buildings in the country, where

energy efficient strategies would also differ, as a result of the Brazilian climatic variety.

The original idea was to focus on developing commercial patterns, given the system

standardization concerning energy expenditures, thus creating a smaller number of variants.

Besides, artificial conditioning – preponderant in commercial buildings –, is seen as one of the

main causes for the high energy consumption, along with inefficient equipment. In light of these

topics, it is likely that both ventilation and lighting are to be held as the most important points as

to bioclimatic projects.

3.1.1 – THE BRAZILIAN AND PORTUGUESE STANDARDS

The Portuguese program, as in Brazil, follows similar patterns to those already adopted

for household appliances, being currently extended to all new buildings. It differs, though, from

the Brazilian model, by being mandatory for carrying building constructions and large

refurbishments out. The most relevant step Portugal ever took was creating a regulation for the

architects to effectively use energy simulation tools for building designing. We have strong

reasons to believe a similar process will take place in Brazil as soon as its standards become

mandatory.

3.2 –BIOCLIMATIC STUDIES

The altitude tropical climate, prevailing over Formiga and Nova Lima, is relatively

mild, with average mean temperature varying from 13º to 29ºC, being also characterized by

rainy summers and dry winters. For both studies the climate of Belo Horizonte (lat.19º56’ S and

long. 43º56’W) was used, as it’s the closest city with available data.

PICTURE 05: Solar Chart for Belo Horizonte

PICTURE 06: Givoni’s Diagram

Analyzing climatic data in light of Givoni’s Diagram, the following conclusions were

reached: large areas between buildings should be built, thus allowing the wind to circulate –

minding to prevent them, however, from recurrent cold winds; opening dimensions between 25

to 40% the wall surface; adequate opening protection against hard rains and excessive sun

exposure; a minimum 8 hour thermal transmission time for walls and roof; well isolated roofing

and proper rain drainage.

4- STRATEGIES APPLIED

4.1- CULTURAL CENTER

The Cultural Center rating was made in account of the envelope structure (windows,

walls and roof areas), as well as color specifications and component materials – besides lighting

and conditioning systems, so the global heat transmission coefficient could be calculated. The

items were evaluated according to prescriptive equations for bioclimatic zone three – as stated

by the national standards (ABNT 15220-3/2005) –, which corresponds to both Formiga and

Nova Lima.

Solutions for the final design came from a sustainable social/economic/environmental

performance-oriented approach, from which some guiding topics were defined. Considering

environmental performance, the following variants may be highlighted: adequate solar

orientation; wind capturing and cross ventilation; natural light utilization; thermal performance

of building materials; direct sunstroke prevention; use of low environmental impact materials.

After defining building system

specifications, the prescriptive method was

applied to the building, using the above-

mentioned equation in order to obtain the final

performance of the building, where:

EqNumEnv - equivalent number for the envelope;

EqNumDPI - equivalent number for the lighting system;

EqNumCA - equivalent number for the air conditioning;

EqNumV – equivalent number for natural conditioning;

APT – floor area of non-conditioned transitory spaces;

ANC – floor area of non-conditioned permanent spaces;

AC – floor area of conditioned spaces;

AU – used area;

b – points obtained for bonuses varying from 0 to 1. PICTURE 07: Final Label for the Culture Center

4.2 – HOUSING DEVELOPMENT

In order to obtain a proper implementation of the design, a climatic data survey was

carried out, taking into account wind behavior, humidity condition and solar position. The same

indicators were tested through low scale models and in loco measurements, aiming low rates

concerning land movements, in order to preserve the natural surface of the land.

PICTURE 08: Study of climatic variables on the land

PICTURE 09: Cross Ventilation in apartment interior

PICTURE 10: Bioclimatic Measures adopted in Housing Development

Technology usage concerning the project may be linked to the utilization of an

independent building structure that could be easily assembled; predominant using of local

material and recycled wood; acoustic protection between apartments – as double walls (thus

reducing air conditioning system usage); using of high performance envelopes and cross

ventilation; suspended gardens and breathing zones for wind permeability, as well as abundant

vegetation for shadowing and creation of microclimates; using of solar bulkheads for sunburn

prevention; solar collectors and photovoltaic panels; visible piping and water pressure

regulating valves for faucets, showers and toilets; rainwater harvesting for toilets; individual

water meter sets for each residential unit; concentration of wet areas in west façade (leeward

façade – air outlet); efficient lighting systems and presence sensors; PROCEL labelling in

common use equipments, such as freezers and water pumps; selective waste collection areas;

social integration areas; and a reduced number of parking spots and alternative proposals for

public transportation, thus giving priority to pedestrians over vehicles.

5- CONCLUSION

As every new process, the brazilian energy efficiency labelling is still at trial and in

improvement, as researches and application studies are being carried out. One can notice,

though, how civil construction professionals get interested in obtaining the National Label of

Energy Conservation.

Many of the technologies applied to efficient buildings imply on a more significant

starting project investment, though their cost should not be overlooked, as energy expenses

unbalance the figures. Anyhow, both studies showed that considering energy efficiency and

bioclimatic aspects in early stages of building design process allows enhancing the building

overall performance. For it to happen, however, several changes concerning the way buildings

are developed in Brazil must take place. In order to prove the energy efficiency of adopted

strategies, the architect must have proper technological knowledge of the systems’ performance,

and material specifications ought to be made in early stages, which doesn’t actually happen in

most building developments. Professionals must be integrated from the beginning so that energy

alternatives can effectively be explored in their full range.

Although bioclimatic projects may present higher building costs over traditional ones,

they have great appeal to the market and may as well contribute to brazilian’s voluntary

labelling.

6- REFERENCES

ABNT – ASSOCIAÇÃO BRASILEIRA DE NORMAS TÉCNICAS. NBR 15220-2:

Desempenho térmico de edificações – Parte 2: Métodos de cálculo da transmitância

térmica, da capacidade térmica, do atraso térmico e do fator solar de elementos e

componentes de edificações. Rio de Janeiro, 2005a.

_____. NBR 15220-3: Desempenho térmico de edificações – Parte 3: Zoneamento

bioclimático brasileiro e estratégias de condicionamento térmico passivo para habitações

de interesse social. Rio de Janeiro, 2005b.

_____. NBR 5413 : “Iluminância de Interiores”. Rio de Janeiro, 1992.

MINISTÉRIO DAS MINAS E ENERGIA – Regulamento Técnico da Qualidade para

Eficiência Energética de Edifícios Comerciais, de Serviços e Públicos, 2009, disponível em:

http://www.labeee.ufsc.br/eletrobras/etiquetagem/downloads.php > Acesso em: 20/11/ 2009.