Designing a 24-hour perturbation method for the estimation of a building heat transfer coefficient

Verification of the actual thermal performance of a building envelope after renovation is likely to become a useful key for performance contracting in the frame of heavy retrofit operations in buildings. Some existing methods such as the co-heating method, use on-site measurements to estimate the Heat Transfer Coefficient, or its inverse the overall thermal resistance. Although reliable and accurate, they need several days to several weeks of undisturbed measurements which can be rather inconvenient for building occupants and quite expensive in terms of operational costs. This paper investigates perturbation methods to design a 24-h heat input signal that would ensure an accuracy similar to or better than other perturbation methods to estimate an overall thermal resistance of the building envelope. The paper first studies 256 different squared heating signals in a numerical methodology to determine common characteristics of high-scoring 24-h signals. An experimental campaign in a wooden-framed house tested one of the high-scoring signals. The experimental results showed estimation errors higher than expected but consistent with the literature.

Optimal design of mass timber panels as dynamic insulation: simulations of steady and transient heat exchange

Mass timber panels could be designed as heat exchangers for use in building envelopes. Fresh air, drawn through geometrically optimized channels in the panel, is pre-tempered with building heat that would otherwise be lost to the exterior via conduction. Recent experiments have shown that timber heat exchanging panels can approach U ~0.1 W/m2K – but there are potential limitations. The sizing correlations which predict panel geometry and steady heat exchange must be numerically calibrated for building-scale contexts, the heat-exchange efficiency must be verified virtually, and practical thresholds for transient response time must be determined. This study uses numerical simulations to investigate these factors for one design ‘case’ of timber panels, and establishes a methodology for studies of further cases.

Technology 5.0 in architecture based on the understanding of environmentalism

Technology that developed rapidly in the late 19th century was the beginning of modern times and brought significant changes in every aspect of human life, including architecture. Starting from technology 1.0 until 5.0, technology still has a role in the field of architecture. On one side, technology offers convenience for humans to monitor buildings through the operating system and increases the value of life through its architectural style which is represented by the construction system and materials. On the other hand, technological developments also present problems. The problem that occurs due to technological development that are experienced globally is environmental damage. The purpose of this study is to determine the appropriate technology for use in buildings based on an understanding of environmental science. This study uses a qualitative method regarding the primary literature from books and journals (national and international). The results of this study concluded that through understanding the science of environmentalism, the basis for creating a design must begin with an understanding of the natural conditions of the design area. Henceforth, technology in architectural buildings is not in the form of mechanical technology that potentially increases the amount of building heat, but rather in technology that supports the natural performance inside the building in the form of wall material, new approach in terms of building openings, development of solar panel, windmills, and chimneys technology.

Development of a Decisional Procedure Based on Fuzzy Logic for the Energy Retrofitting of Buildings

This paper concerns the development of an automatic tool, based on Fuzzy Logic, which is able to identify the proper solutions for the energy retrofitting of existing buildings. Regarding winter heating, opaque and glazing surfaces are considered in order to reduce building heat dispersions. Starting from energy diagnosis, it is possible to formulate retrofitting proposals and to evaluate the effectiveness of the intervention considering several aspects (energy savings, costs, intervention typology). The innovation of this work is represented by the application of a fuzzy logic expert system to obtain an indication about the proper interventions for building energy retrofitting, providing as inputs only few parameters, with a strong reduction in time and effort with respect to the software tools and methodologies currently applied by experts. The novelty of the paper is the easy handling properties of the developed tool, which requires only a few data about the buildings: not many such methods were developed in the last years. The energy requirements for winter heating before and after particular interventions were evaluated for a consistent set of buildings in order to produce the required knowledge base for the tool’s development. The identified appropriate inputs and outputs, their domains of discretization, the membership functions associated to each fuzzy set, and the linguistic rules were deduced on the basis of the knowledge determined in this was. Therefore, the system was successfully validated with reference to further buildings characterized by different design and architecture features, showing a good agreement with the intervention opportunities evaluated.

Can Underground Buildings Be Beneficial in Hot Regions? An Investigation of Field Measurements in On-Site Built Underground Construction

Globally, there has been a remarkable growth in the number of underground constructions (UGC) such as railways, offices, hospitals and shopping malls. This expansion is a result of urban area extensions that are limited by the availability of buildable land. Underground construction can also be used to protect people from the harshness of the outdoor conditions. The aim of this research is to investigate the impact of underground construction in hot regions. The major issue with most of the current UGC is the lack of natural ventilation and daylight. This has a clear negative impact on the user’s perception and comfort. The new design elevates the external walls to place some of the windows above ground for the purpose of natural ventilation and providing a view. The study conducted an experiment using an underground room enhanced with field measurements to ascertain the indoor temperature as well as relative humidity. In addition, the study used an energy simulation to calculate building heat transfer and solar heat gain. It was revealed that the use of UGC in hot regions promoted with the addition of natural ventilation can lower the indoor temperature by 3 °C in summer.