Even though tightened building energy efficiency standards are implemented periodically in many countries, existing buildings continually consume a momentous quota of the total primary energy. Energy efficiency solutions range from material components to bulk systems. A technique of building construction, referred to as prefabricated architecture (prefab), is increasing in reputation. Prefab encompasses the offsite fabrication of building components to a greater degree of finish as bulk building structures and systems, and their assembly on-site. In this context, prefab improves the speed of construction, quality of architecture, efficiency of materials, and worker safety, while limiting environmental impacts of construction, as compared to conventional site-built construction practices. Quite recently, a 57 story skyscraper was built in 19 days using prefabricated modules. From the building physics point of view, the bulk systems and tighter integration method of prefab minimizes thermal bridges. This study seeks to clearly characterize the levels of prefab and to investigate the performance of modular prefab; considering acoustic constrain, seismic resistance, thermal behavior, energy consumption, and life cycle analysis of existing prefab cases and, thus, provides a dynamic case study-based review. Generally, prefab can be categorized into components, panels (2D), modules (3D), hybrids, and unitized whole buildings. On average, greenhouse gas emissions from conventional construction were higher than for modular construction, not discounting some individual discrepancies. Few studies have focused on monitored data on prefab and occupants’ comfort but additional studies are required to understand the public’s perception of the technology. The scope of the work examined will be of interest to building engineers, manufacturers, and energy experts, as well as serve as a foundational reference for future study.

Bamboo is a natural building material that can be found in the tropical to mild temperate regions. It has been used from ancient times for its natural strength and flexibility. The renewed interest during the 1980s in bamboo as a construction material has revitalized bamboo not only as a cheap material but also as a durable material. Many bamboo-based building materials have also been developed which is more suitable for the modern construction needs. Bamboo has many environmental benefits which has made it a favorite green building material. This review critically studies not only the environmental aspects when bamboo is used as a building material but also its social and economic aspects, to understand its sustainability impact.

The performance of the building envelope predominantly determines the ultimate energy performance throughout the lifecycle of a building. A sustainable alternative to enhance roof performance while limiting heat flux through a roof is integrating passive techniques such as green roof. Particularly, green roof performance is sensitive to local climate. The main objective of this study was to evaluate the evapotranspiration effect of an extensive green roof on annual energy consumption of an office building in relation to the humid continental climate of Republic of Korea. The dynamic behavior of green roof and building energy performance were investigated through a parametric simulation method using green roof module in EnergyPlus coupled with jEPlus. Structural data of the reference building and ASHARE 90.1-2007 operational schedules were used as inputs for baseline building model while inputs for the green roof module were based on experimental data sets. Due to the influence of the humid conditions and local wind current on the evapotranspiration process, it was generally found that high leaf area index (LAI) reduced cooling energy demand and somewhat reduced heating energy demand as well; corresponding to the highest daily evapotranspiration fluxes of 4.79 mm day⁻¹ in summer and 1.80 mm day⁻¹ in winter. Increasing LAI from 20% to 100% cover increased evapotranspiration flux by 10.4% in summer and 80.2% in winter. Thus to minimize energy losses in winter, foliage cover must be carefully considered. Within limitations specified, the overall annual building energy consumption deceased by 90.9 GJ (3.7%).

Photovoltaic-thermal (PVT) collectors combine photovoltaic modules and solar thermal collectors, forming a single device that receives solar radiation and produces electricity and heat simultaneously. PVT collectors can produce more energy per unit surface area than side-by-side PV modules and solar thermal collectors. There are two types of liquid-type flat-plate PVT collectors, depending on the existence of glass cover over PV module: glass-covered (glazed) PVT collectors, which produce relatively more thermal energy but have lower electrical yield, and uncovered (unglazed) PVT collectors, which have relatively lower thermal energy with somewhat higher electrical performance. In this paper, the experimental performance of two types of liquid-type PVT collectors, glazed and unglazed, was analyzed. The electrical and thermal performances of the PVT collectors were measured in outdoor conditions, and the results were compared. The results show that the thermal efficiency of the glazed PVT collector is higher than that of the unglazed PVT collector, but the unglazed collector had higher electrical efficiency than the glazed collector. The overall energy performance of the collectors was compared by combining the values of the average thermal and electrical efficiency.

BIPV (Building Integrated Photovoltaic) system is a building envelope technology that generates energy by converting solar energy into electricity. However, after producing electrical energy, the remaining solar energy is transferred as heat, raising the temperature at the rear of the BIPV module, and reducing electrical efficiency. On the other hand, a PVT (Photovoltaic Thermal) collector is a device that generates electricity from a PV module and at the same time uses the heat transferred to the air layer inside the collector. In general, the performance of air-type PVT collectors is based on energy analysis using the first law of thermodynamics. Since this performance does not take into account the loss amount, it is not the actual amount of power generation and preheat of the collector that can be used. Therefore, an exergy analysis based on the second law of thermodynamics considering the amount of energy loss must be performed. In this paper, an air-type PVT collector to which perforated baffles were applied was tested through outdoor experiments based on ISO 9806 standard. The total energy (thermal and electrical characteristics) and exergy according to the flow rate (100, 150, and 200 m³/h), solar radiation, and rear temperature of the PV module of the air-type PVT collector were analyzed. As a result, the total exergy efficiency of the air-type PVT collector with perforated baffles was 24.8–30.5% when the total energy efficiency was 44.1–63.3%.

In this study, the techno-economic impacts of nanofluids used as coolants to enhance the overall performance of a photovoltaic/thermal PV/T system, in comparison with conventional fluids, are discussed. A transient mathematical analysis was performed to evaluate the technical aspects and energy performance of the PV/T system. The proposed model is used to predict the annual thermal and electrical power outputs of a PV/T system based on CuO nanofluid, Al2O3 nanofluid, and conventional fluids. Economic and environmental analyses of the PV/T systems were performed by taking into account energy payback period, energy production factor, net CO₂ mitigation, and net CO₂ credit. Because of their greater energy unit area and levelized energy cost, nanofluid based PV/T systems have a lower payback period and better economic savings than those of conventional collectors. Using water, Al₂O₃ nanofluid, and CuO nanofluid, the net CO₂ mitigation and net CO₂ credit are 6.4 tons and 156.8 USD, 6.9 tons and 171.2 USD, and 7.4 tons and 181.6 USD, respectively, for 30 years life of the PV/T system. For typical industrial applications, PV/T systems with nanofluids should be considered as competitors to water-based PV/T collectors.