Multi-objective optimisation of bio-based thermal insulation materials in building envelopes considering condensation risk

Abstract

The reduction in energy demand for heating and cooling with insulation materials increases the material related environmental impact. Thus, implementing low embodied energy materials may equilibrate this tradeoff. Actual trends in passive house postulate bio-based materials as an alternative to conventional ones. Despite that, the implementation of those insulators should be carried out with a deeper analysis due to their hygroscopic properties. The moisture transfer, the associated condensation risk and the energy consumption for seven bio-based materials and polyurethane for a building-like cubicle are analysed. The performance is evaluated combining a software application to model the cubicle (EnergyPlus) and a tool to optimize its performance (jEPlus). The novelty of this optimization approach is to include and evaluate the effects of moisture in these insulation materials, taking into account the mass transfer through the different layers and the evaporation of the different materials. This methodology helps optimise the insulation type and thickness verifying the condensation risk, preventing the deterioration of the materials. The total cost of the different solutions is quantified, and the environmental impact is determined using the life cycle assessment methodology. The effect of climate conditions and the envelope configuration, as well as the risk of condensation, are quantified. The results show that cost and environmental impact can be reduced if bio-based materials are used instead of conventional ones, especially in semiarid climates. Condensation risk occurs for large thicknesses and in humid climates. In our case studies, hemp offered the most balanced solution.

Energy assessment of wood-frame vertical envelope solutions applied in educational establishments of southern Chile

“…In order to evaluate the improvement of thermal performance of educational establishments utilizing different envelope solutions, Energy Plus Dynamic Simulations is utilized, since this method is internationally validated and several studies utilize it (CITEC UBB, 2012a; Ko, Gosti, & Kristl, 2018;Méndez, Capozzoli, Cascone, & Sassone, 2015;Rodriguez-ubinas, Montero, Porteros, & Vega, 2014;Rubeis, Nardi, Ambrosini, & Paoletti, 2018;Torres-rivas, Palumbo, Haddad, Cabeza, & Jiménez, 2018). The research methodology is divided in four stages.…”

Comparative life cycle assessment of bio‐based insulation materials: Environmental and economic performances

“…By contrast, nonrenewable materials such as expanded polystyrene (EPS) contribute to an immediate increase in global warming potential (GWP), for example through their energy‐intensive production process (Pittau et al, 2019). Bio‐based insulation materials can help mitigate depletion of nonrenewable resources and also contribute to the passive control of indoor air conditions (temperature and humidity) via hygroscopicity (Romano et al, 2019; Torres‐Rivas et al, 2018). They are non‐irritant, rendering them more user‐friendly, and being biodegradable lead to less pollution when disposed of (Lawrence, 2015).…”

“…Nonrenewable insulation materials, such as polystyrene and mineral wool, have a considerable cost advantage over bio-based materials through their sheer market dominance. However, bio-based insulations can reduce environmental impacts in comparison to nonrenewable materials (Torres-Rivas et al, 2018).…”

Thermal, physical and mechanical properties of surface overlaid bark-based insulation panels

“…Besides the increasing request for high thermal performance and 'near-zero-energy' consumption buildings, recent emerging trends and issues in the area of sustainable development and low environmental impact require the utilization of bio-based related materials rather than conventional ones such as mineral wool or petro-chemical based insulation mats (Torres-Rivas et al 2018). Thermal insulation panels made of biomass, also referred to as 'bio-insulations', have been increasing rapidly due to their availability as renewable, low-cost and eco-friendly materials.…”