Performance of Wood-Based Panels Integrated with a Bio-Based Phase Change Material: A Full-Scale Experiment in a Cold Climate with Timber-Frame Huts

Conservation Environments' Effect on the Compressive Strength Behaviour of Wood-Concrete Composites

This paper addresses the issues in making wood-concrete composites more resilient to environmental conditions and to improve their compressive strength. Tests were carried out on cubic specimens of 10 × 10 × 10 cm³ composed of ordinary concrete with a 2% redwood- and hardwood-chip dosage. Superficial treatments of cement and lime were applied to the wood chips. All specimens were kept for 28 days in the open air and for 12 months in: the open air, drinking water, seawater, and an oven. Consequently, the compressive strength of ordinary concrete is approximately 37.1 MPa. After 365 days of exposure to the open air, drinking water, seawater, and the oven, a resistance loss of 35.84, 36.06, 42.85, and 52.30% were observed, respectively. In all environments investigated, the untreated wood composite concrete's resistance decreased significantly, while the cement/lime treatment of the wood enhanced them. However, only 15.5 MPa and 14.6 MPa were attained after the first 28 days in the cases of the redwood and the hardwood treated with lime. These findings indicate that the resistance of wood-concrete composites depends on the type of wood used. Treating wood chips with cement is a potential method for making these materials resistant in conservation situations determined by the cement's chemical composition. The current study has implications for researchers and practitioners for further understanding the impact of these eco-friendly concretes in the construction industry.

Trends in Chemical Wood Surface Improvements and Modifications: A Review of the Last Five Years

Increasing the use of wood in buildings is regarded by many as a key solution to tackle climate change. For this reason, a lot of research is carried out to develop new and innovative wood surface improvements and make wood more appealing through features such as increased durability, fire-retardancy, superhydrophobicity, and self-healing. However, in order to have a positive impact on the society, these surface improvements must be applied in real buildings. In this review, the last five years of research in the domain of wood surface improvements and modifications is first presented by sorting the latest innovations into different trends. Afterward, these trends are correlated to specifications representing different normative, ecologic and economic factors which must be considered when expecting to introduce a wood treatment to the market. With this review, the authors hope to help researchers to take into consideration the different factors influencing whether new innovations can leave the research laboratory or not, and thereby facilitate the introduction of new wood surface treatments in the society.

A State of the Art of the Overall Energy Efficiency of Wood Buildings-An Overview and Future Possibilities

The main goal of this study was to review current studies on the state of the art of wood constructions with a particular focus on energy efficiency, which could serve as a valuable source of information for both industry and scholars. This review begins with an overview of the role of materials in wood buildings to improve energy performance, covering structural and insulation materials that have already been successfully used in the market for general applications over the years. Subsequently, studies of different wood building systems (i.e., wood-frame, post-and-beam, mass timber and hybrid constructions) and energy efficiency are discussed. This is followed by a brief introduction to strategies to increase the energy efficiency of constructions. Finally, remarks and future research opportunities for wood buildings are highlighted. Some general recommendations for developing more energy-efficient wood buildings are identified in the literature and discussed. There is a lack of emerging construction concepts for wood-frame and post-and-beam buildings and a lack of design codes and specifications for mass timber and hybrid buildings. From the perspective of the potential environmental benefits of these systems as a whole, and their effects on energy efficiency and embodied energy in constructions, there are barriers that need to be considered in the future.

Cellulose Nanofibrils Endow Phase-Change Polyethylene Glycol with Form Control and Solid-to-gel Transition for Thermal Energy Storage

Green energy-storage materials enable the sustainable use of renewable energy and waste heat. As such, a form-stable phase-change nanohybrid (PCN) is demonstrated to solve the fluidity and leakage issues typical of phase-change materials (PCMs). Here, we introduce the advantage of solid-to-gel transition to overcome the drawbacks of typical solid-to-liquid counterparts in applications related to thermal energy storage and regulation. Polyethylene glycol (PEG) is form-stabilized with cellulose nanofibrils (CNFs) through surface interactions. The cellulosic nanofibrillar matrix is shown to act as an organogelator of highly loaded PEG melt (85 wt %) while ensuring the absence of leakage. CNFs also preserve the physical structure of the PCM and facilitate handling above its fusion temperature. The porous CNF scaffold, its crystalline structure, and the ability to hold PEG in the PCN are characterized by optical and scanning electron imaging, infrared spectroscopy, and X-ray diffraction. By the selection of the PEG molecular mass, the lightweight PCN provides a tailorable fusion temperature in the range between 18 and 65 °C for a latent heat storage of up to 146 J/g. The proposed PCN shows remarkable repeatability in latent heat storage after 100 heating/cooling cycles as assessed by differential scanning calorimetry. The thermal regulation and light-to-heat conversion of the PCN are confirmed via infrared thermal imaging under simulated sunlight and in a thermal chamber, outperforming those of a reference, commercial insulation material. Our PCN is easily processed as a structurally stable design, including three-dimensional, two-dimensional (films), and one-dimensional (filaments) materials; they are, respectively, synthesized by direct ink writing, casting/molding, and wet spinning. We demonstrate the prospects of the lightweight, green nanohybrid for smart-energy buildings and waste heat-generating electronics for thermal energy storage and management.

Experimental Study of Using Micro-Encapsulated Phase-Change Material Integrated into Hemp Shive Wallboard

Phase change materials (PCMs) are now widely known as potential additives for building insulation materials to provide a thermal mass effect that helps conserve energy and maintain a comfortable indoor temperature. Therefore, the study presented in this paper focuses on an experimental investigation of the specific heat capacity and thermal conductivity of hemp shive mixed with PCMs. Industrially manufactured organic PCM-S50 received from MikroCaps Ltd. (Slovenia) has been used to further enhance respective properties of the product samples. The experimental boards were made from hemp shive by directly mixing 5% encapsulate PCMs into the mass. Cold pressing was used to manufacture the boards with Kleiberit urea formaldehyde resin glue as a binding agent. The experimental boards were made as 25 mm thick single-layer parts with a density of 300 ± 20 kg/m3, which qualify them as low-density boards. By adding nanocapsules during the board manufacturing process, the heat capacity is increased by 62%. Based on the great potential of using latent heat, it becomes a possible solution for the development of new technologies related to the automatic regulation of an indoor microclimate.

Bio-Based Phase Change Materials Incorporated in Lignocellulose Matrix for Energy Storage in Buildings—A Review

Due to growing consciousness regarding the environmental impact of fossil-based and non-sustainable materials in construction and building applications, there have been an increasing interest in bio-based and degradable materials in this industry. Due to their excellent chemical and thermo-physical properties for thermal energy storage, bio-based phase change materials (BPCMs) have started to attract attention worldwide for low to medium temperature applications. The ready availability, renewability, and low carbon footprint of BPCMs make them suitable for a large spectrum of applications. Up to now, most of the BPCMs have been incorporated into inorganic matrices with only a few attempts to set the BPCMs into bio-matrices. The current paper is the first comprehensive review on BPCMs incorporation in wood and wood-based materials, as renewable and sustainable materials in buildings, to enhance the thermal mass in the environmentally-friendly buildings. In the paper, the aspects of choosing BPCMs, bio-based matrices, phase change mechanisms and their combination, interpretation of life cycle analyses, and the eventual challenges of using these materials are presented and discussed.

The Impact of Additives on the Main Properties of Phase Change Materials

The main drawback of phase change materials (PCMs) is their low thermal conductivity, which limits the possibilities of a wide range of implementations. Therefore, the researchers, as found in the literature, proposed several methods to improve the thermal conductivity of PCMs, including inserting high thermal conductivity materials in nano-, micro-, and macro-scales, as well as encapsulation of PCMs. However, these inserts impact the other properties of PCMs like latent heat, melting temperature, thermal stability, and cycling stability. Hence, this paper aims to review the available in the open literature research on the main properties of enhanced PCMs that undergo solid–liquid transition. It is found that inserting high thermal conductivity materials and encapsulation results in improved thermal conductivity of PCMs, but it decreases their latent heat. Moreover, the insertions can act as nucleating agents, and the supercooling degree can be reduced. Some of the thermal conductivity enhancers (TCEs) may prevent PCMs from leakage. However, some test results are inconsistent and some seem to be questionable. Therefore, this review indicates these discrepancies and gaps in knowledge and points out possible directions for further research.

Streamlined Life Cycle Assessment of an Innovative Bio-Based Material in Construction: A Case Study of a Phase Change Material Panel

Research Highlights: This is the first study that analyzes the environmental performance of wood-based phase change material (PCM) panels. Background and Objectives: Life cycle assessment (LCA) is a powerful environmental management tool. However, a full LCA, especially during the early design phase of a product, is far too time and data intensive for industrial companies to conduct during their production and consumption processes. Therefore, there is an increasing demand for simpler methods to demonstrate a company’s resource efficiency potential without being data or time intensive. The goal of this study is to investigate the suitability of streamlined LCA (SLCA) tools and methods used in the building material industry, and to assess their robustness in the case study of a wood-based PCM panel. Materials and Methods: The Bilan Produit tool was selected as the SLCA tool and a matrix LCA was selected as the most commonly used SLCA method. A specific case study of a wood-based PCM panel was selected with a focus on its application in building construction in the province of Québec. Results: As a semi-quantitative LCA method, the matrix LCA provided a quick screening of the product life cycle and its hotspot stages, i.e., life cycle stages with high impact. However, the results of the full LCA and SLCA tools were quantitative and based on scientific databases. The use of the PCM panel and heating energy had the highest environmental impacts as compared to other inputs. The results of the full LCA and SLCA also identified energy consumption as a hotspot. Insufficient material or processes in the SLCA databases was one of the reasons for the difference between the results of the SLCA and full LCA. Conclusions: The examined SLCA methods provided proper explanations for the bio-based material in construction, but several limitations still exist, and the methods should be improved to make them more robust when implemented in such a specific sector.