• Energy Research

Reducing energy consumption in the construction sector is urgently needed. In Chile, where income distribution is unequal and the cost of energy is high, energy demand is seriously affected, especially in vulnerable households. Hence, it is essential to establish public policies with more realistic energy-saving goals to address this situation. However, reliably predicting the energy performance of buildings remains a challenge. For this reason, this study aims to identify and evaluate the impact of the variables associated with energy performance in vulnerable households in Central-Southern Chile and propose values that would reduce the gap. A sensitivity analysis was conducted to achieve this, adjusting the energy performance parameters in a base model with data analyzed using local standards. In addition, field information was collected in 93 households to obtain the actual energy consumption. The main results show that the variables that most impacted performance were infiltration, COP, heating setpoints, and schedules, which generated a 60% difference between the theoretical and actual consumption.

Data simulated for occupancy profiles, usually based on standard occupancy schedules, must be validated against real measurements, and many studies have pointed out the gap between them. This problem is more pronounced in homes that are not heated by grid-connected energy sources, such as wood-burning stoves, because the meter cannot provide a real-time estimate. In Central-South Chile, 74% of homes are heated by wood stoves, causing an acute problem of air pollution in several urban areas. The government is trying to solve this problem, but at the moment there is no data on occupancy profiles, hence it is not possible to estimate the energy intensity for heating. This exploratory study aims to clarify to what extent occupancy profiles can be estimated from PM 2.5 pollution levels. To this end, publicly available data on PM 2.5 concentrations in 17 cities in central-south Chile was used as a proxy to build occupancy schedules for homes heated by wood stoves. The results show that there is a clear relationship between pollution levels and occupancy intensity, and that the latter does not follow the schedules outlined in international standards or building codes. The results and methodology can be replicated in cities where air pollution is driven by wood stoves, allowing public authorities to have access to accurate occupancy schedules and providing them with reliable data to address local air pollution problems The research group “Confort ambiental y pobreza energ´etica (+CO-PE)” of the University of the Bío-Bío, the Thematic Network 722RT0135 “Red Iberoamericana de Pobreza Energ´etica y Bienestar Ambiental” (RIPEBA) financed by the call for Thematic Networks of the CYTED Program for 2021, and the Thematic Network 723RT0151 Red Iberoamericana de Eficiencia y Salubridad en Edificios” (IBERESE) financed by the call for Thematic Networks of the CYTED Program for 2022 for supporting this research Project “ANID Fondecyt Regular 1200551-Energy poverty prediction based on social housing architectural design in the central and centralsouthern zones of Chile Index to analyze and reduce the risk of energy poverty”, funded by the National Agency for Research and Development (ANID, in Spanish) Universidad de Granada / CBUA

Adaptive comfort models have emerged as a sustainable way of providing comfort in connection with local climate. Additionally, climate change has posed an additional challenge. In previous studies, the authors clarified how climate change would affect the feasibility of the adaptive comfort model at a worldwide scale, but local considerations for some countries remained unsolved. This study presents the first comprehensive research on the applicability of the adaptive comfort model in Japan not only for current, but also for future scenarios considering the climate change. Remarkable differences across Japanese regions were found, especially between the Northern underpopulated regions of Hokkaidō and Tōhoku and the cities that belong to the Taiheiyō Belt. In general, the adaptive comfort model will find application both in current and future scenarios, but natural ventilation will not play an important role. Special attention should be drawn to the potentials saving of cooling degrees that can be achieved if adaptive setpoint temperatures become commonplace in the future in the Kantō region. These results pave the way for the consideration of the adaptive comfort model as a resilient strategy to adapt to the future changes in climate scenarios for the building industry. © 2020 Elsevier Ltd

Domestic hot water (DHW) consumption in dwellings can play a key role in the development of policies that are focused on energy poverty, and in improving energy efficiency, among other aspects. There is an important variability observed with DHW among different countries due to technical, sociological, climatic, and economic factors. Most studies that deal with DHW predictions are based on stochastic models, and only a few apply time series or statistical methods. In the case of Chile, the country is undergoing a policy development process, and there is little information about DHW consumption. As a result, it is fundamental to have DHW consumption prediction models that are focused on dwelling. For this reason, the study analysed the possibility of using time series models to make future estimations about monthly domestic hot water (DHW) consumption. To this end, consumption data obtained from 98 apartments between 2015 and 2021 were used, and 3 approaches were applied namely, exponential smoothing, basic structural model (BSM), and state-space model (SSM). The results showed that exponential smoothing and state-space methods allowed to obtain satisfactory results with regard to percentage error and confidence levels. Therefore, these models could be used to make future estimations of domestic hot water (DHW) consumption.

Including recycled waste material in cement mixes, as substitutes for natural aggregates, has resulted in diverse research projects, normally focused on mechanical capacities. In the case of recycled glass as an aggregate, this provides a noticeable improvement in thermal properties, depending on its dosage. This idea raises possible construction solutions that reduce the environmental impact and improves thermal behavior. For this research, an extended building typology that is susceptible to experiencing the risk of energy poverty has been chosen. The typology is typical for social housing, built using mortar blocks with crushed glass. First, the basic thermophysical properties of the mortars were determined by laboratory tests; after that, the dynamic thermal properties of representative constructive solutions using these mortars were simulated in seven representative climate zones in Chile. An analysis methodology based on periodic thermal transmittance, adaptive comfort levels and energy demand was run for the 21 proposed models. In addition, the results show that thermal comfort hours increases significantly in thermal zones 1, 2, 3 and 6; from 23 h up to 199 h during a year. It is in these zones where the distance with respect to the neutral temperature of the m50 solution reduces that of the m25 solution by half; i.e., in zone 1, from −429 °C with the m25 solution to −864 °C with the m50. This research intends to be a starting point to generate an analysis methodology for construction solutions in the built environment, from the point of view of thermal comfort.

Today, identifying energy poverty is one of the scientific community's challenges. In this sense, using Geographic Information Systems (GIS) assumes getting to know which areas are the most vulnerable. This study considers the development of a new territory energy poverty evaluation indicator, called Poverty Adaptive Degree Hourly Index (PADHI). The novelty of this indicator is that it combines the number of inhabitants in poverty with the hourly heating and cooling degrees of each climate, determined using adaptive thermal comfort limits based on ASHRAE 55-2017. The area studied focuses on Chile and its 346 municipalities. The application of the adaptive comfort model can exceed 90% in the north of the country and be below 20% in the most meridional areas. The results also outlined that the municipalities defined as PADHI's 10th decile are those which have a higher risk of energy poverty in their population, a higher percentage of income poverty and climatic severity. A cluster analysis was also run for this decile, identifying two risk groups with the aim of identifying the critical areas. This methodology applied to Chile, but international in nature, allows identifying priority areas on which the measures needed to reduce energy poverty can be focused. © 2020 International Energy Initiative

Many studies are nowadays focused on the application of energy conservation measures (ECMs) to building sector because of the reductions of both greenhouse gases and energy consumption set by the European Union. Heating, Ventilating and Air Conditioning (HVAC) systems are the main causes of most energy consumption in the existing buildings. One of the methods to reduce energy consumption is the modification of setpoint temperatures adapted to external climate conditions but maintaining acceptable comfort levels. The adaptive comfort model of ASHRAE 55–2017 uses the prevailing mean outdoor temperature, which records temperatures of the previous days weighted by a constant α which depends on weather changes. This paper analyses the possibilities of optimizing building energy saving with setpoint temperatures according to the α-value and the number of previous days considered. A total of 390 simulations were conducted by considering three representative climate zones of Spain. The results showed that the α-values between 0.4 and 0.6 had the lowest energy consumption. The use of a low number of previous days also achieved greater reductions in heating energy consumption, whereas a larger number of days was applied to cooling energy consumption. This study makes progress in using adaptive setpoint temperatures optimally to reduce the energy consumption in the building sector. © 2019 Elsevier Ltd

Most of the operational energy needed by the housing sector is used to compensate energy losses or thermal gains through the building’s envelope. As a result, any improvement in the thermal behavior will provide important opportunities to reduce energy consumption. This research analyzes improvements in the thermal envelope in social housing in the Greater Concepción area in Chile using adaptive thermal comfort models and thermal insulation investments. The objective set out is to evaluate the economic reduction of thermal envelope improvement costs for dwellings, which entails using the adaptive thermal comfort model obtained through monitoring and the surveys applied to the users of social housing in Concepción (CAS), against the international adaptive thermal comfort models established by the EN 15251:2007 and ASHRAE 55-2017 standards. Finally, it is concluded that, on having applied the social housing adaptive thermal comfort model (CAS), execution costs are reduced by between 28.8% and 58.2%, reaching a time of comfort in free oscillation similar to that obtained from applying the models of the EN 15251:2007 (74.2%) and ASHRAE 55-2017 standards (59.9%).