• Energy Research

Nowadays, the importance of implementing energy efficiency (EE) measures is growing significantly worldwide, based on its potential to reduce energy demands and mitigate climate change effects. Paraguay is a developing country with the highest per capita hydroelectric energy generation in the world, but only 18% of local consumption is hydroelectric and 41% of its energy matrix corresponds to oil products. This paper aims to analyse the importance the Country places on EE as a strategy towards sustainable development and to highlight as EE is an effective pathway to mitigate the climate changes and contrast their effects. The authors initially provide an insight into the climate scenarios for Paraguay and underline the effects of the climate changes on the buildings’ comfort. Subsequently, the authors provide, by resourcing a bibliographic review, a description of the Paraguayan sectors of greater energy consumption, its policies and targets set for increasing EE. Besides, the main EE projects developed by other neighbouring South American countries are analysed to show the level of development of each one in the scope of EE and to offer a reference basis of potential virtuous solutions to be adopted in Paraguay. A focus on the building sector is also made to provide a foundation for policy analyses to enhance EE in this sector. As a result of this review, evidence that EE is beginning to take part in Paraguay’s public policies was found, with the leaders becoming aware of its importance. Nevertheless, many concrete results could not be achieved as of yet and overcoming these barriers still involve a great challenge. Regarding the building sector, few advances have been noticed regarding the regulations of buildings’ thermal performance, a reason for which the National objectives set need to be more specific to achieve greater collective awareness to enforce them. Finally, key actions are recommended for Paraguay aiming to improve EE levels to face the climate change phenomenon.

This research seeks to evaluate the impact of climate change (CC) on the thermal performance of buildings. In particular, it is focused on historical residential buildings located in Asuncion, Paraguay, a city characterised by a humid subtropical climate. Energy dynamic simulations of a representative building in its original state and an energy efficient version were assessed to evaluate the effectiveness of common energy retrofit measures under future climate conditions. Low and high Representative Concentration Pathways climate scenarios for 2030, 2050 and 2070 are employed with a CORDEX climate model and compared with observed weather data of 2009. Two thermal comfort assessment methods are considered, the statistic and the adaptive thermal comfort approach, where operative temperatures and overheating and underheating rates are analysed. As expected, the results show that the projected temperature rise will lead to an increment of discomfort rates, but it could be mitigated by energy refurbishment measures. Thus, CC effects on thermal performance of buildings are relevant and must be considered for the development of adaptation strategies able to manage this phenomenon. At present, Paraguay does not have any energy building codes and, instead, the results of this paper underline their needs with a substantial impact on society and building industry of Paraguay since it demonstrates that the creation of energy buildings codes is highly necessary to face CC impact on buildings.

Nowadays, awareness concerning the need to use energy efficiently is increasing significantly worldwide, thus, improving the energy efficiency levels in the building sector has acquired high importance because of their energy saving potential. However, several intervention options are available to achieve high energy efficiency levels in buildings, and the choice must be made considering the efficiency of the solution and the costs involved. Considering this, the present research aimed to develop a parametric study of several energy retrofit solutions for buildings located in the hot-humid climate of Paraguay, in order to analyse their efficiency in terms of comfort rates and cooling energy needs. Furthermore, the Analytic Hierarchy Process (AHP) is employed as a decision-making method to choose the most suitable intervention considering the investment costs required. Thus, threshold values of thermal transmittance for the building thermal envelope components are established through a parametric study and sensitivity analysis of the simulations results. Considering that Paraguay does not have national building energy codes, the outcomes of this research will constitute a support and contribute for the thermal parameters regulation of buildings aiding to improve the energy efficiency of Paraguayan buildings.

Abstract Nowadays, increasing buildings’ energy efficiency represents an opportunity to improve their thermal performance and adapting them to the global warming effects. However, finding the most suitable intervention for heritage buildings represents a challenge since the best energy retrofit solution has also to achieve the preservation of the building’s original characteristics. This work seeks to evaluate the thermal performance of a dwelling located in the Historic Centre of Asuncion. Subsequently, several retrofitting solutions for the building envelope were assessed to determine the most efficient solution for the building and climate under analysis. As results, energy-efficient solutions guaranteeing optimal conditions of habitability are proposed.

Abstract The assessment of building energy performance through dynamic simulations has been increasing significantly in recent years since it represents a key strategy for the correct design of highly efficient buildings. Results of dynamic energy simulations are affected by many uncertainties, and its reliability depends on the accuracy of the input variables. One of the most influential variables is the climate surrounding the building, a reason why the use of accurate weather data files is essential, but experimental datasets are not always available. In this context, this paper analyses numerical weather datasets obtained from different regional climate models by comparing them with real data; in addition, it evaluates their impact on the energy performance of a historical building in Asuncion through dynamic simulations. The database of five different weather data sources is compared with observed meteorological data in order to assess their accuracy through statistical analyses. Moreover, some methodologies to estimate diffused and direct components of the global solar radiation are evaluated, with the objective of solving the problem of missing direct and diffused solar data components from the meteorological codes. Subsequently, weather data files are generated to quantify the influence of measured/simulated meteorological data on the evaluation of building energy performance. The results obtained in this paper show that the simulated meteorological data agree very well with real observations for the year under study. Also, the simulations of the building energy performance delivered similar values to those obtained using the real weather dataset. Therefore, the regional climate models can represent a reliable tool for building energy performance assessment, and mainly for the calibration of building energy models when measured weather data is not available.