Thermal Performance Assessment of Envelope Retrofits for Existing School Buildings in a Hot–Humid Climate: A Case Study in Chennai, India

This study aims to propose building envelope retrofit packages for existing naturally ventilated school buildings in the hot–humid climatic region of Chennai, India. Indoor thermal parameters were collected through field studies from nine sample classrooms of a selected school building in May 2019, between 9.00 am and 4.00 pm. The thermal performance assessment of the existing building was performed by examining the discomfort hours using the CBE thermal comfort tool. Envelope retrofit strategies gathered from the literature and building standards were applied and studied through simulation. The findings reveal the enormous potential to increase the thermal comfort of existing school buildings through envelope retrofit measures. The results demonstrate that the whole-building temperature can be reduced up to 3.2 °C in summer and up to 3.4 °C in winter. Implementing retrofit measures to the building envelopes of existing buildings will help school owners to increase the comfortable hours of whole buildings by up to 17%. In comparison, annual energy savings of up to 13% for the whole building can be made by enhancing the thermal performance of the building envelope. The findings will also help architects to optimise thermal performance and energy usage with minimal interventions.

Evaluation of Temporary COVID-19 Testing Sites at Brussels Airport, Belgium: Users' Comfort and Privacy

This paper explored the temporary facilities created during the pandemic for use as COVID-19 test centers at Zaventem Airport, the main airport for the city of Brussels, Belgium. The possibilities of modular construction technology and the impact of the building envelope on users' perception of indoor space comfort and privacy were closely observed. The three main problem statements were as follows: (1) the COVID-19 crisis indirectly influenced the creation of temporary modular buildings with glass envelopes;(2) the modular envelope is adaptable to the existing context;and (3) the envelope meets the needs of the users. This study's objectives were to identify the critical factors for users' well-being in temporary modular buildings, and to conduct factor comparisons among different users and between different building-enclosure systems. The study data were collected through a subjective assessment using a SWOT analysis and a survey questionnaire. The glass facade affected the users' acceptance levels of comfort and privacy. The main results show that the users were satisfied with the level of comfort and dissatisfied with the level of privacy. This information can be used to identify areas for improvement and provide useful feedback to designers and engineers about specific design features and operating strategies for temporary modular emergency healthcare buildings.

Feasibility of Using Energy Performance Contracting for the Retrofit of Apartment Buildings in Slovakia

This study is focused on the feasibility of using energy performance contracting (EPC) for the retrofit of two apartment buildings constructed using precast concrete technologies in Slovakia decades ago. The retrofit packages were defined, and their suitability for EPC was evaluated through discounted payback. The uncertainties in the profitability calculations were covered by designing five possible economic developments and defining input ranges instead of just single inputs. The measures in the technical systems were shown to be more feasible than the retrofit of the building envelopes. The potential to finance the selected measures for technical systems through EPC was further evaluated. It was shown that, for at least one of the two buildings studied, the EPC was recommended only for the economic developments with a notable increase in energy prices compared to the baseline that referred to the situation before the Covid-19 pandemic. In the best case, the payback was four years for one building and seven years for the other;thus, both were potentially suitable for EPC. However, for a complex retrofit, the EPC must be combined with a different funding source to also finance other retrofit measures.

Phase-Change Material Design for Thermoelectric Generator-Assisted Building Integrated Photovoltaic

As the coronavirus pandemic has brought about global economic recession and reduction in greenhouse gas emissions, energy efficient building retrofitting has become a comprehensive solution to increase the employment rate and reduce the energy consumption of buildings. This situation requires more energy-efficient integrated generation systems. In this study, an integrated generation system is proposedfor building integrated photovoltaic, thermoelectric generator, and phase change material as an enhanced generation system for buildings. In the proposed system, the phase change material absorbs solar radiation as latent heat within the melting temperature, increasing the photovoltaic conversion efficiency. Additionally, the thermoelectric generator harvests additional electricity as the temperature difference is maintained during the phase change. The total generated energy of the proposed system highly depends on the melting temperature and thickness of the phase change material. Therefore, the appropriate melting temperature and thickness design conditions of the phase change material were derived with the following simulations based on transient energy balance equations in 12 daily profiles. As a result, the optimal melting temperature increased by 5.4°F (3.6°C) and 1.9°F (1.04°C) with an insolation increase of 317 Btu/ft2 (1000 Wh/m2) and a 1.8°F (1°C) increase in ambient temperature, respectively. In addition, the optimal thickness increased by 0.04 in (2.5 mm) with an insolation increase of 317 Btu/ft2 (1000 Wh/m2).

Optimal Balance between Heating, Cooling and Environmental Impacts: A Method for Appropriate Assessment of Building Envelope’s U-Value

In Europe, the recent application of regulations oriented to zero-energy buildings and climate neutrality in 2050 has led to a reduction in energy consumption for heating and cooling in the construction sector. The thermal insulation of the building envelope plays a key role in this process and the requirements about the maximum allowable thermal transmittance are defined by country-specific guidelines. Typically, high insulation values provide low energy consumption for heating;however, they may also entail a risk of overheating in summer period and thus negatively affect the overall performance of the building. In addition, the embodied energy and related emissions caused by the manufacturing and transportation processes of thermal insulation cannot be further neglected in the evaluation of the best optimal solution. Therefore, this paper aims to evaluate the influence in terms of embodied and operational energy of various walls’ thermal insulation thicknesses on residential buildings in Europe. To this end, the EnergyPlus engine was used for the energy simulation within the Ladybug and Honeybee tools, by parametrically conducting multiple iterations;53 variations of external wall U-value, considering high- and low-thermal-mass scenarios, were simulated for 100 representative cities of the European context, using a typical multifamily building as a reference. The results demonstrate that massive walls generally perform better than lightweight structures and the best solution in terms of energy varies according to each climate. Accordingly, the wall’s thermal transmittance for the samples of Oslo, Bordeaux, Rome and Almeria representative of the Continental, oceanic temperate, Mediterranean, and hot, semi-arid climates were, respectively: 0.12, 0.26, 0.42, and 0.64 W/m2K. The optimal solutions are graphically reported on the map of Europe according to specific climatic features, providing a guidance for new constructions and building retrofit.

Compliance with Building Energy Code for the Residential Sector in Egyptian Hot-Arid Climate: Potential Impact, Difficulties, and Further Improvements

Building energy codes are considered to be an effective policy tool for energy reduction worldwide. However, their application and effectiveness are still limited in developing countries. In Egypt, the residential sector is promising for energy savings, as most of the existing residential buildings are aged with low thermal performance and non-conformance with energy codes. This study aims to raise the awareness of promoting the Egyptian residential energy codes among construction parties, especially end-users, by quantifying the environmental impacts, in terms of energy savings and thermal comfort enhancement. Moreover, it attempts achieving a nearly zero energy building by integrating several energy-efficient measures with renewable energy sources. Thus, in this study, a typical residential building in Cairo was chosen for simulation. The simulation results revealed that applying energy code instructions for building envelope, lighting enhancement and increases in cooling set-points, from 24 °C to 25 °C, saved 37.85% of annual electrical energy and resulted in a cooling reduction of 50.53%. Furthermore, the photovoltaic system incorporation succeeded in transforming the building into a nearly zero energy building. Concerning thermal comfort, the application of passive energy-efficient measures significantly influences indoor thermal comfort, with a 30% reduction in discomfort hours during the cooling season, which represents the main concern in hot climate regions.

Thermo-Energy Performance of Lightweight Steel Framed Constructions: A Case Study

The building sector continues to play an essential role in reducing worldwide energy consumption. The reduced consumption is accompanied by stricter regulation for the thermotechnical design of the building envelope. The redefined nearly Zero Energy Building levels that will come into force for each member state will pressure designers to rethink the constructive details so that mandatory levels can be reached, without increasing the construction costs over an optimum level but at the same time reducing greenhouse gas emissions. The paper aims to illustrate the main conclusions obtained in assessing the thermo-energy performance of a steel-framed building representing a holistically designed modular laboratory located in a moderate continental temperate climate, characteristic of the south-eastern part of the Pannonian Depression with some sub-Mediterranean influences. An extensive numerical simulation of the main junctions was performed. The thermal performance was established in terms of the main parameters, the adjusted thermal resistances and global thermal insulation coefficient. Further on, the energy consumption for heating was established, and the associated energy rating was in compliance with the Romanian regulations. A parametric study was done to illustrate the energy performance of the investigated case in the five representative climatic zones from Romania. An important conclusion of the research indicates that an emphasis must be placed on the thermotechnical design of Light Steel Framed solutions against increased thermal bridge areas caused by the steel’s high thermal conductivity for all building components to reach nZEB levels. Nevertheless, the results indicate an exemplary behaviour compared to classical solutions, but at the same time, the need for an iterative redesign so that all thermo-energy performance indicators are achieved.