Energy consumed by heating, ventilation and air conditioning systems (HVAC) in buildings represents an important part of the global energy consumed in Europe. Thermal energy storage is considered as ...a promising technology to improve the energy efficiency of these systems, and if incorporated in the building envelope the energy demand can be reduced. Many studies are on applications of thermal energy storage in buildings, but few consider their integration in the building. The inclusion of thermal storage in a functional and constructive way could promote these systems in the commercial and residential building sector, as well as providing user-friendly tools to architects and engineers to help implementation at the design stage. The aim of this paper is to review and identify thermal storage building integrated systems and to classify them depending on the location of the thermal storage system.
•TES implementation in buildings should be as helpful as possible for architects and engineers.•Hence, TES systems integration is considered relevant aspect in building designs.•Active systems integrated in buildings are classified depending on their location.•Building core activation systems are demonstrated to have potential in new buildings.•Suspended ceilings became interesting for energetic refurbishment in old buildings.
•New concretes with PCMs for multifunctional applications are proposed and tested.•Micro- and pioneering macro-encapsulated paraffin-based PCMs are considered.•PCM reduce mass density, increases ...thermal inertia and do not affect strain ductility.•Reliability and strength of concretes with PCMs can be compatible with structural use.•Thermo-energy dynamic analysis shows that they behave as thermal buffers.
Energy performance in buildings and integrated systems represents a key aspect influencing anthropogenic emissions worldwide. Therefore, novel multifunctional materials for improving envelope thermo-energy efficiency through passive techniques are presently attracting notable researchers’ effort. In this view, the integration of phase change materials (PCMs) into structural concrete showed interesting effects in enhancing the material thermal capacity while keeping proper structural strength. This work presents a multiphysics thermo-mechanical investigation concerning innovative concretes incorporating paraffin-based PCM suitable for structural-thermal multifunctional applications in high-energy efficiency building envelopes. Both classic microPCM-capsules and the novel more pioneering macroPCM-capsules with 18 °C phase transition temperature are used for the new composite preparation. Results confirm the thermal benefits of PCM and demonstrate that the addition of PCM reduces the mass density of concrete by almost twice PCMs weight. Average compressive strength decreases with increasing the amount of PCM, but its coefficient of variation is not as negatively affected, which is promising in terms of structural reliability. Indeed, a 1% weight content of microPCM and macroPCM results in reduced coefficients of variation of the compressive strength, determining an increase in characteristic compressive strength. This benefit might be associated to both a filler effect of the PCM and to a positive thermal interaction between inclusions and cement hydration products. The multifunctional analysis showed promising performance of PCM-based macro-capsules as aggregates, even if their concentration is relatively minor than the classic micro-capsules already acknowledged as effective additives for high energy efficient cement-based materials.
•Experimental study at pilot plant scale of addition of fins in LTES systems.•Comparison of two LTES tanks, with and without fins, during a charging process.•Hydroquinone was selected as ...PCM.•Effective thermal conductivity was compared at different thermal power ratios.•Increase in measured thermal effective conductivity was 4.11–25.83%
Solar cooling is a promising solution to overcome the high energy demand of buildings. Nevertheless, the time dependent nature of the solar source leads to the need of storage systems in order to better match the energy demand and supply. For this purpose, thermal energy storage was considered during last decades as the optimal solution at commercial scale. Latent thermal energy storage offers higher energy densities together with more constant outlet temperature than sensible heat storage, but the low thermal conductivities of PCMs represents the main drawback which limits its applicability. Several studies based on heat transfer enhancement techniques applied in latent thermal energy storage have already been performed. Specifically, the technique of adding fins in storage tanks, which is the most known and studied. However, there are few experimental studies at pilot plant scale focused on this technique and less on the analysis of the heat transfer enhancement through the parameter effective thermal conductivity. This paper presents an experimental study where this parameter is determined and compared using of two identical latent storage tanks, one with 196 transversal squared fins and another one without fins. In this case, hydroquinone was selected as PCM. A set of six experiments was performed at pilot plant of the University of Lleida (Spain), combining three different HTF flow rates and two temperature gradients between HTF inlet temperature and initial PCM temperature. Experimental results showed that the addition of fins can increase the effective thermal conductivity between 4.11% and 25.83% comparing the experiment with highest and lowest thermal power supplied to the PCM, respectively.
Energy consumption trends in residential and commercial buildings show a significant increase in recent decades. One of the key points for reducing energy consumption in buildings is to decrease the ...energy demand. Buildings envelopes are not just a structure they also provide protection from outdoor weather conditions always taking into account the local climate. Thermal energy storage has been used and applied to the building structure by taking advantage of sensible heat storage of materials with high thermal mass. But in recent years, researchers have focused their studies on the implementation of latent heat storage materials that if well incorporated could have high potential in energy demand reduction without occupying the space required by sensible storage. The aim of this study is to review the thermal energy storage passive systems that have been integrated in building components such as walls, ceilings or floors, and to classify them depending on their component integration.
•TES could be integrated in buildings envelope using sensible or latent heat method.•Solar walls registered highest energetic benefits in sensible heat storage systems.•PCM incorporation depends on the method used and where the material is embedded.•Wallboards with 25% or less PCM registered low effect and not economically feasible.•Macro-encapsulated PCM higher potential and no materials incompatibility problems.
Phase change materials (PCM) can be employed in many fields because of their capacity to absorb and release energy when it is necessary. Nowadays, the number of studies about these materials is ...increasing because of their benefits in energy systems. This paper reviews the previous researches and developments on microencapsulated phase change materials (MPCM) in thermal energy storage (TES) systems, focusing on the different methods of encapsulations and also the different applications of these materials. This review aims to be a useful guide for the researchers in this area, because it explains the different types of phase change core materials, the different shells, the methods to microencapsulate these PCM, the most used techniques to characterize these microencapsulated phase change materials, and a revision of the main applications.
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•Framework to judge transition toward 4th generation district heating is proposed.•Multi-objective optimization for evaluating heat pump effect is projected.•Various control ...strategies for the heat pump operation are investigated.•Stakeholder perspective is examined using KPIs of 4th generation district heating.•Heat pump integration in district heating is a sustainable and competitive solution.
The movement toward the 4th generation district heating (4GDH) embraces a great opportunity to support the future smart energy development concept. However, its development calls for addressing technological and economic obstacles aligning with the need for a reformation of the energy market to ensure the quality of service. In this context, our paper presents a comprehensive analysis based on a multi-objective optimization framework incorporating an artificial neural network-based model for the possibility of integrating heat pump (HP) into solar assisted district heating system (SDHS) with seasonal thermal energy storage to support the sustainable transition toward 4GDH. The study evaluates the performance of the proposed system with the help of key performance indicators (KPI) related to the 4GDH characteristics and key stakeholders for possible market growth with consideration for the environmental benefits. The proposed analysis is applied to a small neighbourhood of 10 residential buildings located in Madrid (Spain) to investigate the optimal integration of HP under different control strategies into a SDHS. Inherent the SDHS operator perspective, the results reveal a significant improvement in the stabilization of the SDHS performance due to the HP integration where the solar field temperature never exceeds 80 °C, and the seasonal storage tank (SST) temperature stands at 85.4 °C. In addition, the share of solar energy stands above 86.1% with an efficiency of 73.9% for the SST, while the seasonal HP performance factor stands above 5.5 for all optimal scenarios. From the investor viewpoint, an energy price of 59.1 Euro/MWh can be achieved for the proposed system with a payback period of 26 years. Finally, from the policymaker perspective, along with the significant economic and sustainable improvement in the SDHS performance, a substantial environmental improvement of 82.5% is achieved when compared to the conventional boiler heating system. The proposed analysis reflects a great motivation for different stakeholders to propose this system as a path toward the 4GDH in the future district energy systems.
•Sustainability and social justice deserve attention in sustainable transitions.•Responsible research and innovation is used for envision sustainable transitions.•Responsible research and innovation ...offers tools for policy integration process.•An understanding of the context is vital in terms of replicating an intervention.•Context description must be considered as part of the validation methodology.
Aspects of sustainability and social justice deserve special attention in the research and innovation landscape in Europe. In this vein, the inclusion of innovative research and innovation policies, such as Responsible Research and Innovation, devoted to mainstream social outcomes, to deploy democratic governance of science, and to drive innovation into a direction that is ethically acceptable, societally desirable and sustainable are noteworthy. However, substantial efforts are required when it comes to integrate the interactions between renewable energy research and energy and climate policies within responsible approaches. In order to adapt responsible research and innovation approach for the purpose of building an alternative context and assessment approach for sustainable transitions, this paper presents a review of approaches around sustainability and social justice dimensions. The thresholds of this endeavour are detailed in terms of the challenges for the integration, the identification of the inhibitors and facilitators of policy integration and the proposal of the levels for a methodology for this integration. The results show that the different readings and understanding of the contexts and dimensions and the existence of knowledge gaps between policy targets and the outcomes of research and innovation can be considered inhibitors for the integration. In contrast the interlinks between dimensional concepts, backgrounds and rationales appear as facilitators. The innovative contribution of this paper is focused on the contextualization of the dimensions through the use of socio-technical and multi/inter/trans and cross-disciplinary approaches. The authors conclude that the process of introducing a more holistic and alternative approach opens the re-envision of policy elements. Moreover, RRI offers an innovative perspective to the transition approach as well as tools for decision-making and policy processes assessment, in an arena where constant innovation is taking place and new structures, processes and metrics are necessary to guide this process.
The use of paraffin, salts and salt hydrates as phase change materials (PCMs) have been researched extensively and used in a number of commercial applications. However, metals and metal alloys, which ...possess a high storage density on a volume basis as well as a substantially higher thermal conductivity, has received much less attention. This paper discusses the considerations for the use of metal and metal alloys as phase change materials for high temperature thermal storage applications, as well as summarises the literature on the limited research in this area. Although some pure metals and metal alloys present interesting thermal properties to be used as PCMs in thermal storage systems, there is a lack of understanding on the implications of the metallurgical aspects related to the melting and solidification of these materials under thermal cycling at high temperatures. The main issues to be considered include vapour pressure, undercooling, corrosion, segregation, changes in composition and microstructure, changes in thermal properties and undesired reactions. Further research is needed before these materials can be used as PCMs in thermal energy storage systems in industry.
Advances Toward a Net-Zero Global Building Sector Ürge-Vorsatz, Diana; Khosla, Radhika; Bernhardt, Rob ...
Annual review of environment and resources,
10/2020, Letnik:
45, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The building sector is responsible for 39% of process-related greenhouse gas emissions globally, making net- or nearly-zero energy buildings pivotal for reaching climate neutrality. This article ...reviews recent advances in key options and strategies for converting the building sector to be climate neutral. The evidence from the literature shows it is possible to achieve net- or nearly-zero energy building outcomes across the world in most building types and climates with systems, technologies, and skills that already exist, and at costs that are in the range of conventional buildings. Maximizing energy efficiency for all building energy uses is found as central to net-zero targets. Jurisdictions all over the world, including Brussels, New York, Vancouver, and Tyrol, have innovated visionary policies to catalyze themarket success of such buildings, with more than 7 million square meters of nearly-zero energy buildings erected in China alone in the past few years. Since embodied carbon in building materials can consume up to a half of the remaining 1.5°C carbon budget, this article reviews recent advances to minimize embodied energy and store carbon in building materials.
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