Due to government subsidies, Brazil has witnessed an increase in the installation and use of small solar water heating systems in low-income housing projects. Although the initiative has reduced the load curve during peak times due to the reduced use of electric showerheads, measurement and verification (M&V) are needed to validate the savings. M&V procedures should take into account the social and economic variability of low-income housing developments. To improve M&V in low-income housing projects, this paper presents a methodology for identifying homogeneous subgroups based on their energy-saving potential. This research strategy involved a cluster analysis designed to improve the understanding of what energy savers and other influencing factors exist. A case study in Londrina Brazil was undertaken with 200 low-income families. Five clusters, created based on savings potential, were defined. The results showed that only two clusters demonstrated good electricity savings, representing 47% of families. However, two clusters, or 37%, did not provide satisfactory savings, and the other 16% did not provide any consumption history due to previous use of illegal city electricity connection practices. Therefore, studies confirm the need for a detailed measurement of the representative subgroups to assess the influence of human behaviour on potential SWHS-induced savings.

In Brazil the housing deficit is around 5.5 million houses. To address this need, the government created a programme called “My house, My life”. The main subsidies of the programme are for families earning up to three times the minimum wage. In order to formulate strategies for more energy efficiency buildings, it is necessary to understand the thermal and energy performance of what is being built. This article defines representative projects for typologies being built in the Brazilian social housing sector through the analysis of 108 projects considering two groups of income levels and investigates the thermal and energy performance of the representative projects in relation to the Regulation for Energy Efficiency Labelling of Residential Buildings in Brazil for two bioclimatic zones. Five representative building models were defined. Considering the most common features found on the sample, the study suggests the importance of addresing energy efficiency measures on the sector since current building techniques for social housing shows a tendency towards a low performance in relation to the thermal and energy performance criteria of the Energy Labelling especially for lower income projects. This provides a basis for future policy and allows for more in depth studies within the sector.

The inclusion of solar water heaters available through subsidies of the Brazilian government has benefited more than 300,000 low-income families. Although these subsidies are important for wide implementation of this technology, the actual system performance is unclear. Moreover, it is unclear whether the performance is affected by user behavior in the context of complex socioeconomic issues. The objective of this research is to assess the influence of human behavior on the potential savings induced by solar water heaters. The research strategy integrated qualitative and quantitative measurements. We applied the cluster analysis technique to identify five homogeneous subgroups for a case study in Londrina, Brazil, in which a detailed measurement procedure was implemented to gather data on these subgroups over one year. The measurements were conducted to gain a better understanding of the factors affecting electricity consumed by showering. This study shows that the benefits of solar heaters vary according to the user and use of the technology. The annual energy savings averaged 9.51–18.6 kWh per person. A lack of technological understanding and the difficulty in effectively mixing hot and cold water were the main factors contributing to the inefficient use of the system.

One of the alternatives to reduce building energy consumption recognized and used internationally is establishing standards for the evaluation and classification of buildings in terms of energy performance. In developed countries, the introduction of energy efficiency codes for residential and non-residential buildings started around the time of the first oil crisis in the mid-70s. Ten years later, Brazil has started implemented measures aimed at the conservation and rational use of energy. Initiatives in this regard began with the implementation of the Brazilian Labeling Program, where consumers are provided with information on the energy efficiency of appliances. However, the first energy efficiency law stimulated the most notable improvement in energy efficiency in 2001 after national energy crisis. As a result, the Regulation for Energy Efficiency Labeling of Commercial, Service and Public Buildings (RTQ-C) was released in February 2009 and the Regulation for Energy Efficiency Labeling of Residential Buildings (RTQ-R) was released in November 2010. Nowadays, the labeling of residential, commercial and service buildings is voluntary and the labeling of federal public buildings is mandatory since 2014. This paper presents a review of the building energy efficiency codes and labeling schemes all over the world, an overview of the Brazilian regulations on energy efficiency and discusses the labeling scheme for residential buildings adopted in Brazil. The process of its implementation, strengths and weaknesses in the present labeling scheme and the similarities and differences in relation to international experiences are described. The results obtained to date indicate that a revision is required in order to achieve a more flexible and economically viable process that will enable the program to be established as compulsory.

Evaluation methods can be used to determine what constitutes good energy performance in a building. With an increasing focus on energy use of buildings worldwide, this evaluation assumes a fundamental importance. This paper provides a comprehensive review of the available methods for analysing, classifying, benchmarking, rating and evaluating energy performance in non-domestic buildings.

Methodologies are grouped in five categories: engineering calculations, simulation, statistical methods, machine learning and other methods. Techniques for evaluating buildings are described, their principal applications are shown and limitations are identified. The use of performance evaluation in energy efficiency programmes and standards is mapped.

There is a need to further develop interactions between the main modelling techniques to produce simple, robust and validated models. Also, evaluation techniques must be developed to consider comfort or service provision in the buildings as a factor in energy performance.

Social housing sector is very important in Brazil, due to the necessity of expansion and investments being placed through a substantial government program. Residential buildings are expected to last at least 50 years according to Brazilian standards. Many residential projects in the sector already perform medium or poorly in terms of energy efficiency and thermal comfort today, and their designs are not analysed considering climate change. Therefore, the aim of this paper is to investigate the result of analysing the thermal and energy performance of social housing projects considering climate change, and to assess the impact on the operational phase of introducing energy efficiency measures in the sector, and exploring methods of adaptation to climate change. A representative project of the lower income sector housing was used as case study with the evaluation of measures through thermal and energy simulation with current and future weather files for the cities of São Paulo and Salvador. Results were compared using predicted energy consumption and cooling and heating degree-hours as indicators. The results highlighted some differences related to the climate scenarios and indicator analysed, and showed that the incorporation of energy efficiency measures in current social housing projects is of fundamental importance to minimize the effects of climate change in the coming decades.
 

This study presents a methodology to measure the impact of solar heating systems, on reducing peak demand and on avoided emissions, when applied in low-income housing projects. To this end, a real-time monitoring system was implemented over a year in five clusters representative of a heterogeneous socioeconomic context in new housing subsidized with solar water heating system through the national program “My House, My Life”. The results showed an expressive contribution of the system in reducing the maximum peak demand, obtaining, on average, a 64% reduction in relation to the electric showerhead, predominantly used in the country. The cumulative energy savings of 577 kWh per year resulted in an average of 250 kgCO 2 avoided per housing unit. The extrapolation of the data to 224,000 units already delivered by the national program would result in an economy of 56,089 tCO 2 per year. This study demonstrates the importance of measurement as a strategic tool in public policies for energy efficiency and in the estimation of emissions associated with greenhouse gases. The solar heating system positions itself as an important energy efficiency policy for Brazil, which minimizes the demand for thermoelectric plants during peak hours and postpones investments with new power generation plants.
 

Occupant behaviour has a direct impact on building energy consumption. A better understanding of human-building interactions enables to describe with higher accuracy the occupant behaviour. This paper addresses occupant behaviour in residential buildings, providing a review of current methods in (1) monitoring occupant behaviour, (2) developing occupant behaviour models, and (3) applying occupant behaviour models in building performance simulations. Occupant behaviour studies with focus on residential buildings are presented including both challenges and potential for improving building energy performance.

A multi-parametric sensitivity analysis of Solar Water Heater (SWH) systems was undertaken for the city of Brisbane in Australia using computational models calibrated by experimental data. The models were calculated using EnergyPlus 8.6. The following technical specification parameters were assessed in the modelling: (i) solar collector efficiency; (ii) solar collector area; (iii) tank volume; (iv) tank heat loss; (v) electric back-up heating power rate; (vi) electric back-up heating position (height) for vertical tanks; and (vii) electric back-up heating temperature range. The site-specific parameters included: (i) solar collector direction; (ii) solar collector tilt angle; (iii) solar collector shadowing; (iv) solar collector dust accumulation; (v) hot water pipe insulation; (vi) hot water pipe length; (vii) electricity tariff time-of-use; and (viii) cold water temperature. User behaviour patterns were comprised of the following parameters: (i) end-use water temperature; (ii) end-use water demand; and (iii) end-use time-of-use. For all parameters, two system types were assessed, namely: (i) thermosiphon systems with natural (passive) circulation in collectors and unstratified horizontal hot water storage tanks; and (ii) split systems with forced (pumped) circulation in collectors and stratified vertical hot water storage tanks. The performance of SWHs was analysed considering both energy performance indicators (i.e. total and peak-hour energy consumption, solar fraction and energy intensity) and level of service indicators (i.e. compliance with recommended hot water temperatures for Legionella spp. control and comfort levels). Notwithstanding the prevalence of thermosiphon systems among SWH technologies, results indicate that split systems usually outperformed thermosiphon systems both in terms of energy efficiency and level of service, and hence should be a preferred option for energy efficiency initiatives and policies.

The human dimension plays an essential role in the energy performance of buildings and is considered as significant as technological advances. Several studies highlighted the negative influence of occupant behaviour in underperforming buildings, while some support that technological innovations may reduce human-related uncertainties. Thus, one may consider that fully automated smart buildings are essential to achieve energy efficiency. However, if technology excludes people from decision-making processes, low acceptance and comfort/welfare levels may be reported from users. Therefore, the right combination of humans and technologies are expected to solve these problems. Buildings are emerging as complex Cyber-Physical Systems, including the Social dimension, and this provides an excellent opportunity to achieve high-performance outcomes, considering both technical and social aspects. Thus, the right choice among available up-to-date behavioural sensing – comprising active and passive sensors, as well as Kinect technology – are important in the Internet-of-Things (IoT) era. IoT-driven buildings can use real-time monitoring data to inform users and drive behavioural-based consumption change, which is an important aspect to achieve high-performance buildings and deliver user-centred services. An essential feature in this regard is to allow for human-in-the-loop approaches enabled by human-centric computing and smart devices, which has grown fast in the last few years. This literature review summarises applications and main challenges related to the combination of the human dimension and technological innovations in the building sector. This combination is expected to increase user welfare and reduce the energy consumption in buildings, as human and machine components of intelligence may complement each other regarding building performance.