Thermal Behavior Study Projects

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Energy Performance / Thermal Behavior Projects in Buildings

The energy performance project of buildings, also known as the thermal behavior project, is an essential specialty for the construction, rehabilitation, or expansion of buildings. This project aims to optimize energy consumption and promote energy efficiency, reducing environmental impact, improving quality of life, and minimizing operational costs related to energy use. Given the current energy scenario, it is crucial to implement efficiency concepts in new constructions and rehabilitation projects.

Main Objectives and Strategies

Selection of Materials and Technologies: Use of energy-efficient materials and technologies.
Integration of Systems: More efficient lighting, ventilation, and air conditioning systems.
Renewable Energy: Integrating renewable energy sources wherever possible.

Climatic Data and Energy Efficiency

The energy efficiency of buildings is strongly influenced by local climatic conditions. During the winter, it is important to take advantage of solar energy gains through opaque or glazed surroundings and minimize heat losses. In the summer, the goal is to limit solar gains. This approach considers:

Temperature differences between the interior and exterior.
Average climatic data for each region, allowing a specific approach to the design.

Building Envelope Types

The envelope of a building includes:

External Envelope: Elements that separate the interior from the external environment.
Internal Envelope: Boundaries between useful and non-useful spaces (garages, ventilated spaces).

Thermal requirements for the external envelope are stricter due to greater thermal exchange with the external environment.

Thermal Transmittance Coefficients (U)

The thermal transmittance coefficient (U) measures the amount of heat that passes through a surface of the envelope per unit of time and area. It is influenced by:

The composition of layers.
The presence of air spaces.

The reference published by LNEC (“Thermal Transmittance Coefficients of Building Envelope Elements”) provides detailed information on thermal resistances and U coefficients.

Solar Factor

The solar factor of glazed surfaces evaluates the relationship between solar energy transmitted indoors and incident energy.

In winter, the use of solar radiation for heating is maximized.
In summer, unwanted thermal gains are limited using solar protections (shutters, curtains) and special glass.

Energy Performance and NZEB

The energy performance of buildings considers the needs for:

Heating and cooling.
Ventilation and lighting.
Domestic hot water.

New buildings must meet the nearly zero energy building (NZEB) standards, complying with legal and regulatory requirements to minimize consumption and improve comfort.

Challenges in Old Buildings

For old buildings, rehabilitation is essential for:

Updating thermal insulation.
Replacing windows with more efficient models.
Introducing modern heating and cooling systems.

Solutions like green roofs and renewable energies can also be implemented, balancing efficiency with architectural heritage preservation.

Energy Certification

The energy certificate evaluates the performance of a property (classification from A+ to F), considering annual energy consumption and air quality. During the project, an Energy Pre-Certificate (PCE) is issued by a qualified expert, ensuring compliance with regulations.

Exemptions:

Small single-family properties.
Industrial facilities with no energy consumption.
Ruined buildings (Ruined Declaration).

Recommended Improvements:

Wall insulation.
Solar thermal and photovoltaic systems.
Window replacement.

These measures, detailed in architectural and energy performance projects, contribute to sustainability and provide long-term benefits for owners and the environment.