Sustainable buildings, an unpostponable priority

A series of research conducted in the last 20 years to evaluate the influence of architectural and urban design on the indoor thermal environment and energy consumption in Cuba’s climate conditions, especially on non-residential buildings such as hotel management and service facilities, institutions and schools, to name a few, won one of the 78 national awards of the Academy of Sciences 2021, in the category of Technical Sciences.

The research was led by Doctor of Science and professor emeritus Dania Gonzalez Couret, scientists from the Faculty of Architecture of the José Antonio Echeverría Technological University of Havana (CUJAE in Spanish), with the participation of experts from the University of Camagüey.

Dr. Dania Gonzalez exchanged with Granma newspapers to speak about the fundamental contributions of the study, the multiple solutions suggested and the possibility that these can be inserted in the construction sector.

What are the origins of such a promising result?

-It all started in the early years of this century, when architect Luis Alberto Rueda defended in his undergraduate thesis the role of design in energy consumption for air conditioning in sun and beach hotels.

“Another precedent was related to the outline of a system of multiple solar protection elements, which could be industrially produced in the country, whose benefits in the reduction of energy consumption were demonstrated when applied in the Almendares building of Inmobiliaria CIMEX in 2008.

“Likewise, the research also included the evaluation of the energy sustainability of the Universidad de las Ciencias Informáticas (UCI in Spanish), with proposals to reduce energy demand in the three buildings with the highest energy consumption.

“A doctoral thesis defended some time ago focused on determining the influence of urban context and the orientation of the buildings on solar protection and the reduction of energy consumption. The energy renovation of buildings in Havana’s Vedado neighborhood was also the main topic of another doctoral thesis”.

-How much can architectural solutions contribute to energy saving in our country?

On a global scale, it is recognized that buildings represent almost a third of the total energy consumed and carbon dioxide emissions in a city. This is largely due to environmental conditioning systems (heating and air conditioning), whose demand increases when architectural solutions are not adapted to the urban context and local climate through appropriate and specific designs.

“In the case of Cuba, we have shown, for example, that with appropriate solar protection it is possible to reduce daily energy consumption per room in sun and beach hotels by 13 kWh and using adequate dimensions and appropriate materials for windows and walls between five and 13 kWh, and the color given to the exterior closing surfaces, up to 5 kWh, depending on the proportions and location of the windows, and the type of cover used.

“Similarly, the addition of vegetation to improve the thermal environment in the UCI, proved it was possible to lower the temperature in interior spaces by two degrees Celsius during the afternoon, while with the use of double green roofs in buildings, a very economical solution countrywide, the temperature in interior could decrease up to six degrees.

“The proposed modifications to the NC-220 standard on energy efficiency of buildings, approved at the beginning of this century, would bring about an additional reduction in energy demand, estimated at between 4% and 14%.

Estimates even suggest that on a wide, low-rise, west-facing street, the decrease in energy demand could be in the order of 56 kWh per year per square meter of building floor area.”

– In some recently completed buildings or in the construction stage, there is a prominent use of large glass windows, which cause the well-known greenhouse effect. What do you think about this tendency to ignore our tropical conditions in the design of projects?

-It is inappropriate in our environment to use glass windows without protection against the sun because, when the sun rays penetrating e through them, it traps the heat generated in the interior space (greenhouse effect), causing an increase in temperature and affecting comfort.

“In order to keep the indoor environment cool, air conditioning equipment is forced to increase its workload, with the consequent increase in energy consumption.

Why do these things contrary to the advice of experts on the subject happen?

-Despite the top priority given by the Cuban state to the application of science, technology and innovation in all spheres of national life, as far as architecture and urban planning are concerned, the recommendations of specialists are still not taken into account.

“There are several examples of buildings that have been built with designs that do not correspond to Cuba’s climatic conditions at all.

“Making our cities and buildings more sustainable does not require additional investments, assuming new ways of thinking and acting, and above all, taking advantage of the knowledge of our architects, is the key.”

Translated by ESTI

source: Granma

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