Effect of argon concentration on thermal efficiency of gas-filled insulating glass flat-plate collectors

open access articleInsulating glass flat-plate collectors can save cost by being produced quickly and automatically in insulated glass production facilities, and they can be filled with argon to reduce heat loss. During its lifetime, the collector is likely to lose argon because of gradual material degradation of the sealing. However, information on the influence of the argon concentration on the collector efficiency is limited. Therefore, the objective of this research work was to analyse this effect. A theoretical material property calculation of argon-air mixtures was carried out to determine the convective losses with variable argon concentrations. Thermal collector performance was measured experimentally using an outdoor solar tracker test rig. The results strongly suggest, that the influence of argon concentration on both the convective losses and the thermal efficiency is non-linear. The measurements revealed that an argon concentration of 90 % can increase average thermal performance by percentage points. An increase in argon concentration from 0 % to 50 % has almost twice the effect on average thermal efficiency as an increase from 50 % to 90 %. Concluding from these results, an argon leakage threshold of 2.5 percentage points per year is proposed to avoid disproportionate loss of efficiency over time

Comfort in cold: A novel approach to sustainable building energy efficiency

Kyrgyzstan's high-altitude rural housing sector consumes 3–5 times more energy than European buildings due to ageing infrastructure, lack of insulation, and reliance on non-sustainable resources. One potential solution is the implementation of thermal insulation. However, due to limited public awareness of energy efficiency, inadequate government policies, insufficient technology, and challenging geography, people in rural areas rely on non-sustainable resources such as coal, cow dung, and firewood for heating, which creates a negative impact on the local ecosystems. To close the energy efficiency gap, the paper proposes a sustainable and holistic approach that integrates thermal insulation with effective energy efficiency planning using a staged-renovation approach by utilising locally available insulation materials / resources. The feasibility study presented in the paper was conducted with a simulation-based parametric study to recognise the potential of novel and sustainable insulation structures on building heat demand. This innovative approach can potentially reduce heat demand in high-altitude houses by as much as 70 %, offering a transformative solution. Furthermore, its adaptability makes it transferable to similar high-altitude communities, thus advancing sustainable energy practices for climate change mitigation and contributing to broader sustainable development goals

How to Enhance Energy Services in Informal Settlements? Qualitative Comparison of Renewable Energy Solutions

More than half of the urban population of Sub-Saharan Africa lives in informal housing conditions. While urban areas are, in general, characterized by a high electrification rate, residents of informal settlements are still affected by energy poverty, the use of traditional energy sources and unreliable electricity supply. The aim of the study is to give an overview of different renewable-energy-based solutions which are able to improve local energy provision. These are Solar Home Systems, Mini-Grids, and Energy-Hubs. The technologies are compared to another option for improving energy supply, namely Grid Expansion. The analysis is based on 24 Key Performance Indicators, which can be classified into technical, economic, environmental, social, and political dimensions. The selection of indicators is based on the challenges prevalent in informal settlements that impede a comprehensive, sustainable energy supply. The literature-based indices are used to determine which of the four technologies is a suitable solution for minimizing the challenges prevailing in informal settlements. The resulting matrix provides a holistic comparison and serves as a decision aid in selecting the appropriate technology for future projects in informal settlements, depending on local conditions and the needs of the population. The results show that the Energy-Hub is a valid alternative for energy supply improvement in Informal Settlements

Development of an Evaluation Methodology for the Potential of Solar-thermal Energy Use in the Food Industry

AbstractThe research project ‘Solar Heat in the Liquid Food Industry’ (part of the FORETA Research Network [1]) focused on the development and optimisation of low-temperature heating systems for the liquid food industry. Its main objectives are in energy efficiency, waste heat recovery and the feasibility of a solar-thermal process heating system. Based on the particular simulation results the overall solar-thermal potentials for German breweries and dairies were determined. In this connection a literature review indicated that most of the potential studies on solar-thermal energy use in the industry or related to specific industrial sectors are based on the total use of low-temperature heat. In opposition to these results, the available and mainly limited roof area was found to be a more important aspect for the solar-thermal potential. Hence, the development of a methodology for a site- specific analysis was necessary. The interconnection of only a few defined evaluation criteria resulted in a more realistic estimation of the potential for a solar-thermal heat supply

Residential Building Construction Techniques and the Potential for Energy Efficiency in Central Asia: Example from High-Altitude Rural Settlement in Kyrgyzstan

Building construction in rural Kyrgyzstan is heavily dominated by earthen buildings. Old and inappropriate residential building structures contribute significantly to high domestic space heating energy consumption. Therefore, it is necessary to understand the relevant building construction techniques. However, the scant information on Kyrgyz building techniques, especially for high-altitude rural settlements, was the prime motivation to perform the presented study. The key objective of the study is to investigate residential building construction techniques in high-altitude rural Kyrgyzstan, and this was to be achieved by house visits during field trips, literature review, and pilot interviews with local people. The analysis enabled the detailed identification of individual building envelopes as well as predominant building materials to be recorded. Based on the assessment, a housing profile was created that represents the typical characteristics of traditional rural Kyrgyz houses. Furthermore, the study demonstrates the potential for energy savings in rural Kyrgyz houses of 50–70%. However, local conditions prevent people from making improvements to all domestic energy efficiency parameters simultaneously. Therefore, the study developed a ‘sequential roadmap’ to reduce domestic space heating demand in different phases based on simulation studies. Existing low-income rural Kyrgyz habitations can use the presented roadmap to reduce domestic space heating demand sequentially to overcome financial barriers and, therefore, contribute to establishing sustainable buildings in Kyrgyzstan. These results may be partially replicated in other Central Asian rural communities depending on their location and building characteristics

Electric Two-Wheeler Vehicle Integration into Rural Off-Grid Photovoltaic System in Kenya

In both rural and urban areas, two-wheeler vehicles are the most common means of transportation, contributing to local air pollution and greenhouse gas emissions (GHG). Transitioning to electric two-wheeler vehicles can help reduce GHG emissions while also increasing the socioeconomic status of people in rural Kenya. Renewable energy systems can play a significant role in charging electric two-wheeled vehicles, resulting in lower carbon emissions and increased renewable energy penetration in rural Kenya. As a result, using the Conventional and Renewable Energy Optimization (CARNOT) Toolbox in the MATLAB/Simulink environment, this paper focuses on integrating and modeling electric two-wheeled vehicles (e-bikes) into an off-grid photovoltaic Water-Energy Hub located in the Lake Victoria Region of Western Kenya. Electricity demand data obtained from the Water-Energy Hub was investigated and analyzed. Potential solar energy surplus was identified and the surplus was used to incorporate the electric two-wheeler vehicles. The energy consumption of the electric two-wheeler vehicles was also measured in the field based on the rider’s driving behavior. The modeling results revealed an annual power consumption of 27,267 kWh, a photovoltaic (PV) electricity production of 37,785 kWh, and an electricity deficit of 370 kWh. The annual results show that PV generation exceeds power consumption, implying that there should be no electricity deficit. The results, however, do not represent the results in hourly resolution, ignoring the impact of weather fluctuation on PV production. As a result, in order to comprehend the electricity deficit, hourly resolution results are shown. A load optimization method was designed to efficiently integrate the electric 2-wheeler vehicle into the Water-Energy Hub in order to alleviate the electricity deficit. The yearly electricity deficit was decreased to 1 kWh and the annual electricity consumption was raised by 11% (i.e., 30,767 kWh), which is enough to charge four more electric two-wheeler batteries daily using the load optimization technique

Methodological Evaluation of Storage Systems for Flexible Power Generation from Solid Biomass

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.The increasing number of fluctuating renewable power producers in the electricity grid leads to several challenges in the grid's infrastructure and its operation. Biomass combustion plants, however, can be modified to increase the flexibility of power production by integrating steam storage devices. In this paper, the available storage systems are evaluated, considering the boundaries of the plants and the requirements of power grids and markets. An objective result is generated by conducting a Delphi study using energy experts. The Utility-Value-Analysis method is used to identify the most promising storage concept. Using this methodology, the resulting storage concept is found to be a combination of a steam accumulator and a solid storage

Approaches for dispatchable biomass plants with particular focus on steam storage devices

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.The increasing share of fluctuating energy generation causes new challenges in the power grids. The demand for flexible power plants is increasing. Solid biomass fueled combined heat and power (CHP) plants are able to get modified into dispatchable power plants. In this paper, boundaries for this operation mode are summarized and several measures to achieve a flexible power generation in biomass CHP plants are concluded. The integration of high temperature storage system for buffering the plants steam seems to be the most promising, however the least investigated option. The tasks and necessary features of such storage systems were investigated and a review of available technologies and systems for the storage of steam made

In Search for the Optimal Forest Use Behaviour: Riparian Forest Use in Central Asia, Using the Example of Ak-Tal, Naryn, Kyrgyzstan

Riparian forests are rare and valuable ecosystems in Central Asia, both due to their significance for biodiversity and to their provision of vital ecosystem services to local residents. However, the actual forest use behaviour is under-researched, official figures may not be trustworthy, and the question of over-use is up in the air. This paper sets out to shed light on riparian forest use behaviour by local residents using the example of Ak-Tal Village upon the Naryn River in Kyrgyzstan: Which economic use patterns do they practice (focusing on fuel wood and pasture)? Which other ecosystem services do they recognise? Is there forest over-exploitation? To answer these questions, this study builds on local knowledge, by applying the methods of focus group discussions and a household survey. Results show an extreme discrepancy between official wood consumption figures (50–60 m3 p.a.) and figures based on household wood consumption (310–404 m3 p.a.). The forest also serves as an important winter pasture over the seven months between October and April (stocking density 0.61 livestock units/ha), but payments for these ecosystem services are low, with annually 40 KGS/ha. Local residents are aware of additional material and nonmaterial ecosystem services of the riparian forest. Opinions diverge upon the question if there is forest over-exploitation, potentially because different stakeholders have different concepts of an optimal forest status. Consequently, optimal forest use behaviour can only be defined by the local users themselves, e.g., in a future stakeholder dialogue

Energy Profiling of a High-Altitude Kyrgyz Community: Challenges and Motivations to Preserve Floodplain Ecosystems Based on Household Survey

The floodplain areas along the Naryn River in Kyrgyzstan are essential as they hold the riparian (local) ecosystems because they provide firewood, pastureland, and areas for recreation and protection against erosion. Due to limited access to adequate, reliable, and sustainable energy services, the rural population usually derived their energy needs from multiple natural energy resources (i.e., firewood, charcoal, agricultural residues, animal dung, and wood branches). This is considered a common and predominant practice in rural Kyrgyzstan. This situation leads to a negative impact on local ecosystem services. In addition to that, the reliance on solid fuels contributes to indoor and outdoor air pollution, which is partially threatening the local ecosystem services. By contrast, the employment of renewable-based energy supply systems would substantially reduce the burden on the environment, which is mainly untapped. To integrate renewable energies, it is important to understand the energy behavior of floodplain communities. In that response, the presented article is the first attempt to capture the energy identity of the floodplain community of Kyrgyzstan based on a quantitative energy-based (on-site) household survey. Furthermore, the present research article synthesizes the driving factors that have a (direct or indirect) impact on the energy and local ecosystem services. In addition, the present article proposes a brief pathway for the sustainable energy transition. The article records the recommendation to integrate renewable energies to preserve the local ecosystems of Kyrgyzstan