Performance and environmental sustainability assessment of an integrated solar water heater designed for disassembly

Recent amendments to the Climate Change (Scotland) Bill set an ambitious target of net-zero by 2045 and the Scottish Government has highlighted the need for policy reform to decarbonise heat. Minimum requirement for hot water provision through renewable technologies are already included in Section 7 (Sustainability) of the Scottish Building Regulations. However, with growing demand for affordable housing in Scotland, and modular construction becoming increasingly popular due to its affordability, energy performance and sustainability, there is an urgent need to identify solutions for a renewable provision of heat that aligns with construction trends and societal requirements. This research aims to optimise a unique integrated collector-storage solar water heater (ICSSWH) design for integration into buildings under Scottish weather conditions, underpinned by a lifecycle perspective and incorporating circular economy principles. The ICSSWH evaluated was specifically engineered for integration into modern roof structures, to be compatible with offsite modular construction as a plug-and-play, fit-and-forget system, and designed for disassembly to improve reuse potential at the end of its useful life. Two design configurations were evaluated, baffled and finned, alongside two heat retention methods, additional insulation and a night cover. Extensive field tests were conducted, with the designs embedded into a structural insulated panel, under a realistic draw-off profile to mimic practical application and quantitively assess real-life, seasonal performance. The baffled system outperforms the finned in every scenario and the night cover offers the greatest improvement in heat retention. Life cycle assessment (LCA) complemented field tests to establish whether operational savings achieved by the system would outweigh the embodied impacts. LCA showed that the ICSSWH can recoup both its embodied energy (3.7-5.5 years) and carbon (4.9-13 years) within its useful life. Additionally, the cost analysis demonstrated the economic viability with payback times of 5.8–7.7 years when replacing an electric system. These analyses demonstrates the environmental sustainability of the system, and the element of integration into the roof structure, as part of a pre-built package, illustrates the benefits of its practical application. With extensive uptake of this technology, significant carbon savings could be achieved. If ICSSWHs were integrated into 10,000 new builds, the potential carbon savings would be approximately 13,200 tonnes of CO2e, bringing the operational carbon emissions associated with the hot water demand of the new homes down by 42%. This work advances existing knowledge through: innovative design for disassembly and integration into the roof structure; a circular approach, considering sustainability at the design stage and promoting reuse over disposal; a feasible prototype evaluating real-life performance using a seasonal testing method and realistic draw-off profile

Participação e transdisciplinaridade em Ecosaúde: a perspectiva da análise de redes sociais

A Ecosaúde usa abordagens participativas e transdisciplinares com o intuito de compreender as inter-relações entre os componentes dos sistemas socioecológicos e como estas interações influenciam a saúde das populações humanas. O objetivo do artigo é usar a Análise de Redes Sociais (ARS) para entender o papel das relações de colaboração entre os diversos atores envolvidos nos processos participativos e transdisciplinares em projetos de Ecosaúde. Apresentamos um conjunto de indicadores de ARS para caracterizar a evolução e a equidade de participação e diferenciar a inter e a transdisciplinaridade. A análise foi feita com base na rede de colaboração entre os atores da Iniciativa de Liderança em Ecosaúde para as Enfermidades Transmitidas por Vetores (ETV) na América Latina e Caribe. O processo participativo ficou mais intenso ao longo do projeto, com mais sujeitos envolvidos e um número crescente de colaborações. A cooperação entre os atores das ciências sociais, ambientais e da saúde é pouco equitativa; assim, predominam as ciências da saúde. Os poucos cientistas ambientais presentes estão, porém, ativamente envolvidos em colaborações interdisciplinares. A abordagem tem aplicação ampla para estudar a participação e a transdisciplinaridade em projetos sobre saúde e meio ambiente.Ecohealth uses participatory and transdisciplinary approaches to understand the relationships between the components of socio-ecological systems and how these interactions influence the health of human populations. The article aims to use Social Network Analysis (SNA) to understand the role of collaborative relationships between the various actors involved in participatory and transdisciplinary processes in Ecohealth projects. We present a set of SNA indicators to characterize the evolution and equity of participation and to differentiate the inter and the transdisciplinarity. The analysis was based on the collaboration network among the members of the Ecohealth Field Building Leadership Initiative for Vector-Borne Diseases (VBD) in Latin America and Caribbean. The participatory process intensified throughout the project, with more subjects involved and a growing number of collaborations. Cooperation between members from the social, environmental, and health sciences is unbalanced; thus, health scientists predominate. The few environmental scientists are, however, actively involved in interdisciplinary collaborations. The proposed approach has wide application to study participation and transdisciplinarity in projects about health and environment

Thermal Performance through Heat Retention in Integrated Collector-Storage Solar Water Heaters: A Review

Solar thermal systems are a long-standing technology that is receiving increased attention, in terms of research and development, due to ambitious climate change targets and the need for renewable energy solutions. Integrated collector-storage solar water heaters (ICSSWHs) are a potential contributing solution and numerous studies have focussed on the optimisation of their thermal performance and efficiency. A major drawback of these systems is the heavy heat losses experienced during non-collection periods. To combat this, various heat retention strategies have been proposed and evaluated, including baffles plates, additional insulation, multiple glazing layers, selective coatings, and phase change materials. This paper aims to bring together these studies through a systematic review of the existing literature surrounding the performance of ICSSWH systems, focusing on heat retention. This review provides a comprehensive and up-to-date point of reference on relevant research and developments for researchers in this field

A parametric thermal analysis of refugees’ shelters using incremental design and affordable construction material

The number of people displaced by natural and human made events reached 80 million in 2020 based on the latest report by UNHCR. Emergency housing is often initially in the form of tents, which are then replaced by a more robust solution. One frequently used design is an insulated steel box-like (Inverted Box Rib) structure as it offers a temporary and short build time, including off-site construction. The lack of thermal mass is, at least theoretically, less than ideal in locations with large temperature swings, and extremely high/low internal temperatures have been recorded in such shelters. These locations often coincide with places where large-scale displacements have occurred in recent years. An associated issue is that pre-designed solutions might not be tailored to the culture and needs of the occupants. In this work, we offer an incremental design method that can provide flexibility to suite displaced people’s social needs, simultaneously, we performed extensive thermal modelling/analysis via using vernacular material with high thermal mass to accommodate extreme weather fluctuations. This solution is termed Makazi (‘home’ in Swahili). After disasters, those displaced look for places that feel like home rather than just a house, to alleviate their distress and uncertainty. Thus, ‘Makazi’ aims to provide an affordable, durable and sustainable home with a modular design, while complying with common requirements of hosting countries for temporary structures

Embodied carbon quantification of luminaires using life cycle assessment and CIBSE TM65 methodologies: A comparison case study

The European legislative landscape on sustainability is steadily growing to meet objectives to reach net zero targets by mid‐century. In this context, companies and manufacturers may soon be legally required to provide quantification of the environmental impact of their products and services. A key challenge is applying a consistent and robust methodology that ensures comparability between assessments made by different companies, as there is still fragmentation among environmental impact reporting methodologies. The objective of this study is to analyze and compare the results of two different methodologies for the calculation of the embodied carbon in lighting products using the cradle‐to‐grave approach. One is the globally known life cycle assessment (LCA) method, and the other is Chartered Institution of Building Services Engineers Technical Memorandum 65's (TM65) mid‐level calculation methodology, which has been specifically tailored to building services. The two were applied to six different luminaires to evaluate their differences. Results show that the values of the embodied carbon calculated with TM65 are higher than those calculated with LCA and that the weight of the products plays a crucial role in creating discrepancies between the two methodologies

Beyond recycling: an LCA-based decision-support tool to accelerate Scotland's transition to a circular economy

Resources and waste strategies have recently seen a shift in focus from weight-based recycling targets to impact-driven policies. To support this transition, numerous decision-support tools were developed to help identify waste streams with the highest impacts. However, the majority of these tools focus solely on greenhouse gas emissions and show a narrow picture of the overall environmental impacts. Furthermore, they cover burdens associated with direct waste management activities and hence fall short when it comes to highlighting the substantial benefits that can be achieved by preventing waste in the first place. This paper quantitatively demonstrates the necessity to adopt impact-based targets that go beyond estimating the greenhouse gas emissions of waste and highlights the substantial benefits of waste reduction and prevention. Using a state-of-the-art waste environmental footprint tool, the paper quantifies the overall environmental impacts of Scotland's household waste and shows how targeting ‘heavy’ materials does not necessarily have the highest overall environmental benefit. Results show that embodied environmental impacts of household waste dominate the total environmental burdens, contributing more than 90% to the whole life cycle impacts, and hence policymakers should prioritise interventions that aim at waste reduction and prevention. Moreover, our analysis shows that food and textile wastes are high-priority materials in Scotland, with the largest contribution to overall environmental burdens; up to 42% and 30%, respectively. Considering the overall environmental impacts of specific waste materials will enable policymakers to develop more granular and targeted interventions to accelerate our transition to a sustainable circular economy

Whole-life design and resource reuse of a solar water heater in the UK

Passive solar systems are often designed primarily with efficiency in mind, and research efforts are concentrated towards gaining an increase in performance. However, due to the multiple materials used, their manufacturing processes, a lifespan that is usually shorter than that of buildings that these systems are applied to and the waste generated when they have reached the end of their useful life, a more holistic approach to the design and performance of these systems should be adopted. This paper reports on the environmental impact of a unique integrated collector–storage solar water heater design, experimentally tested under Scottish weather conditions, considering circular economy and reuse potential. As such, the material flows and components used are mapped against the life-cycle stages of existing European standards while ensuring an optimal efficiency. End-of-life considerations and design for disassembly and reuse are assessed and discussed. Energy payback times of 4·5 and 4·6 years can be realised for a circular and a linear approach, respectively. Operational carbon dioxide savings, which far outstrip the embodied carbon dioxide, demonstrate carbon dioxide payback times of just 7 months, when replacing an electric system. The results show that a holistic design, which promotes circular economy principles, does not compromise efficiency and economic viabilit

Decoupling density from tallness in analysing the life cycle greenhouse gas emissions of cities

The UN estimate 2.5 billion new urban residents by 2050, thus further increasing global greenhouse gases (GHG) emissions and energy demand, and the environmental impacts caused by the built environment. Achieving optimal use of space and maximal efficiency in buildings is therefore fundamental for sustainable urbanisation. There is a growing belief that building taller and denser is better. However, urban environmental design often neglects life cycle GHG emissions. Here we offer a novel method that decouples density and tallness in urban environments and allows each to be analysed individually. We test this novel method on case studies of real neighbourhoods and show that taller urban environments significantly increase life cycle GHG emissions (+154%) and low-density urban environments significantly increase land use (+142%). However, increasing urban density without increasing urban height reduces life cycle GHG emissions while maximising the population capacity. These results contend the claim that building taller is the most efficient way to meet growing demand for urban space and instead show that denser urban environments do not significantly increase life cycle GHG emissions and require less land

Participação e transdisciplinaridade em Ecosaúde: a perspectiva da análise de redes sociais

Ecohealth uses participatory and transdisciplinary approaches to understand the relationships between the components of socio-ecological systems and how these interactions influence the health of human populations. The article aims to use Social Network Analysis (SNA) to understand the role of collaborative relationships between the various actors involved in participatory and transdisciplinary processes in Ecohealth projects. We present a set of SNA indicators to characterize the evolution and equity of participation and to differentiate the inter and the transdisciplinarity. The analysis was based on the collaboration network among the members of the Ecohealth Field Building Leadership Initiative for Vector-Borne Diseases (VBD) in Latin America and Caribbean. The participatory process intensified throughout the project, with more subjects involved and a growing number of collaborations. Cooperation between members from the social, environmental, and health sciences is unbalanced; thus, health scientists predominate. The few environmental scientists are, however, actively involved in interdisciplinary collaborations. The proposed approach has wide application to study participation and transdisciplinarity in projects about health and environment.A Ecosaúde usa abordagens participativas e transdisciplinares com o intuito de compreender as inter-relações entre os componentes dos sistemas socioecológicos e como estas interações influenciam a saúde das populações humanas. O objetivo do artigo é usar a Análise de Redes Sociais (ARS) para entender o papel das relações de colaboração entre os diversos atores envolvidos nos processos participativos e transdisciplinares em projetos de Ecosaúde. Apresentamos um conjunto de indicadores de ARS para caracterizar a evolução e a equidade de participação e diferenciar a inter e a transdisciplinaridade. A análise foi feita com base na rede de colaboração entre os atores da Iniciativa de Liderança em Ecosaúde para as Enfermidades Transmitidas por Vetores (ETV) na América Latina e Caribe. O processo participativo ficou mais intenso ao longo do projeto, com mais sujeitos envolvidos e um número crescente de colaborações. A cooperação entre os atores das ciências sociais, ambientais e da saúde é pouco equitativa; assim, predominam as ciências da saúde. Os poucos cientistas ambientais presentes estão, porém, ativamente envolvidos em colaborações interdisciplinares. A abordagem tem aplicação ampla para estudar a participação e a transdisciplinaridade em projetos sobre saúde e meio ambiente