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- PostFeasibility study on electric load adjustment for Rya Wastewater Treatment Plant(2024) RIFAD, Abdulla; KALLUVAYAL BHASKARAN, Sivani; Chalmers tekniska högskola / Institutionen för arkitektur och samhällsbyggnadsteknik (ACE); Chalmers tekniska högskola / Institutionen för arkitektur och samhällsbyggnadsteknik (ACE); Wilén, Britt-Marie; Wilén, Britt-MarieThis thesis investigates the feasibility of adjusting the electric load at the Rya wastewater treatment plant (WWTP), operated by the municipal company Gryaab AB in Gothenburg, Sweden, with the goal of reducing electricity usage momentarily and contributing to the local flexibility market, Effekthandel Väst (EHV). The Rya WWPP consumes approximately 240 GWh of electricity annually, of which most of the electricity is used for inlet pumping and aeration in the activated sludge process, accounting for 70% of the total consumption. As Gothenburg prepares for potential electricity shortages in the years ahead, this study focuses on momentarily reducing electricity usage during the peak hours (morning and evening) through short term and long-term flexibility measures. Flexibility refers to the ability to adjust electricity usage in response to market conditions or grid demands, either by reducing consumption or shifting it to different times. By analysing historical electricity usage data, the report evaluates different scenarios where Gryaab can participate in Effekthandel Väst by momentarily halting the operations or shifting the electricity demand to off-peak hours/periods. Results show that momentary shutdowns of key processes, can lead to significant reductions in electricity consumption. The study compares the financial and operational impacts of short-term versus long-term flexibility. While short-term flexibility offers immediate responses to market conditions and financial benefits, long-term flexibility provides consistent savings and aligns with strategic goals. The findings highlight the socio-economic and environmental benefits of Gryaab’s participation in Effekthandel Väst, including momentary reduced energy consumption and enhanced grid stability. The study concludes that optimised electricity management at the WWTP not only supports Gothenburg’s sustainability targets but also offers substantial cost-savings opportunities during high demand periods.
- PostOptimization of a battery thermal management system: Master’s thesis in Sustainable Energy Systems(2024) Khan, Osaid Mohammad Nasir; Mudliyar, Satyanarayanan; Chalmers tekniska högskola / Institutionen för arkitektur och samhällsbyggnadsteknik (ACE); Chalmers tekniska högskola / Institutionen för arkitektur och samhällsbyggnadsteknik (ACE); Dalenbäck, Jan-OlofThis master’s thesis focuses on the Active Cooling Unit (ACU), a vital component used by Volvo Penta to maintain optimal thermal conditions in battery systems across various applications, including electric on-road, off-road, and Battery Thermal Management System (BTMS) solutions. The ACU employs a secondary loop with a glycol-water mixture as the coolant for heat transfer, effectively separating the refrigerant from the battery cooling circuit. The ACU is critical for ensuring traction batteries operate within their ideal temperature range. Proper thermal management is essential for safe and durable battery performance, enabling quick charging, efficient energy storage, and reliable power delivery. This research investigates the current BTMS, aiming to optimize the thermal performance of the ACU. Key areas of focus include improving heat transfer across components, utilizing waste heat to reduce operational costs, and enhancing overall energy efficiency. The study explores and evaluates the use of internal heat exchangers, demonstrating that modifying the cooling circuit and better controlling heat dissipation can significantly improve system efficiency. The findings of this study have broad applicability in industrial and marine sectors and offer scalable solutions for diverse energy delivery needs, contributing to more sustainable and efficient thermal management practices.
- PostGetting to know nature(2024) Rajala Pettersson, Carl; Chalmers tekniska högskola / Institutionen för arkitektur och samhällsbyggnadsteknik (ACE); Chalmers tekniska högskola / Institutionen för arkitektur och samhällsbyggnadsteknik (ACE); Thuvander, Liane; Elfstrand, PeterThe population of the world is growing. Above all, it is the cities that are growing. How we use land and water, plan and build determines whether we can preserve and develop the capacity of ecosystems to deliver ecosystem services. Global warming, animal extinctions and the poisoning of nature are fundamentally about disruption of natural process or ecosystems. By planning for ecosystem services in human society, the need for technical interventions can also be reduced. Living environments with close and integrated greenery are essential for our health and well-be ing. Spending time in green environments helps to lower blood pressure, heart rate and stress levels. Despite the numerous advantages humans gain from nature, contemporary lifestyles have led to a detachment from the natural world, with a substantial increase in indoor activities. Ecosystem services can be valued in different ways. Biotope area factor is a type of semi-quan titative valuation of ecosystem services. This simplification of the work with ecosystem services has the potential to be a support for architects to evaluate design proposals from an ecosystem services perspective. The purpose of this thesis is to explore ways for sustainable expansions within cities, i.e. densi fication, in relation to urban ecosystem services and residential qualities. The thesis focuses on three ecosystem services: biodiversity, water purification and regulation and pollination. From the theory on residential qualities related to the outdoor environment and biophilic design, evaluation tools are developed. Together with the biotope area factor tool, explorations on urban components and typologies are carried out. The results of the explorations, in combination with knowledge from previous research, forms design strategies. The design strategies are put into practice in a design proposal for the densification of Nedre Norrby in Borås. The design task does also address other challenges in the city. The thesis concludes that the transformation of Nedre Norrby could contribute to ecosystem ser vices in Borås and at the same time create many residential qualities in a new mixed content and high density neighbourhood.
- PostThe potential of assessing harmful algal bloom risks in Swedish raw water sources - A study of four Swedish drinking water sources(2024) CEDERBERG, Björn; ERIKSSON SEGERSTRÖM, Klara; Chalmers tekniska högskola / Institutionen för arkitektur och samhällsbyggnadsteknik (ACE); Chalmers tekniska högskola / Institutionen för arkitektur och samhällsbyggnadsteknik (ACE); Lindhe, Andreas; Bergion, ViktorHigher temperatures and extreme weather due to climate change are expected to increase algae growth in Swedish surface waters, potentially disrupting drinking water production through algal toxins or clogged filters. This project aimed to assess the risks associated with high algal biomass in Swedish surface waters, identify critical conditions that trigger harmful algal blooms, and explore effective strategies for how these risks can be managed. Four case studies (Lerum, Tjörn, Sotenäs, and Sandviken) and a literature review were conducted. The analysis found no correlation between selected parameters and algal blooms in the studied waters, although weather data indicated trends consistent with climate change. The limited raw water data likely influenced the results. It was concluded that municipal risk management for algal growth is inadequate. Improved monitoring, systematic sampling, and the use of daily measurements of pH, turbidity, and water temperature are recommended as indicators of algae growth. If changes in these indicators are detected, they should be followed by visual inspections. Additionally, more extensive measures, such as sampling total biomass or chlorophyll-a, can be used as more precise indicators of algae growth.
- PostDetection of sound from AVAS in urban environments(2024) Demirci, Bircan; Chalmers tekniska högskola / Institutionen för arkitektur och samhällsbyggnadsteknik (ACE); Chalmers tekniska högskola / Institutionen för arkitektur och samhällsbyggnadsteknik (ACE); Forssén, Jens; Bolin, KarlFunctionality of AVAS (Acoustic Vehicle Alert System) faces challenges in urban environments, where background noises may mask AVAS sounds. From a safety perspective, designing AVAS sounds that effectively warn vulnerable road users (without causing extensive environmental noise) is even more crucial in heavy vehicles since they have longer braking distances, greater momentum, and more blind spots than light vehicles. This study aims to contribute to the safety aspects of battery electric trucks (BEV trucks) by exploring their detectability in urban areas and their classification rate, which shows whether they can be distinguishable from cars. In this regard, listening tests were conducted with 51 participants: eight distinct vehicle sounds, five of which belong to a BEV heavy truck, one to an ICE (Internal combustion engine) truck, one to a BEV passenger car, and one to an ICE passenger car. Each vehicle sound was presented both at 10 and 20 km/h. In the first session of the test, participants were tasked with classifying approaching vehicles as either trucks or cars, without additional urban background noise (the equivalent levels are about 45 dB(A)). During the second session, they were tasked with detecting approaching vehicles amidst continuous urban background noise (the equivalent levels are in the range between 57 and 62 dB(A)) and then classifying the detected ones. The results revealed that in the first session of the test, where there was no additional background noise, 50% of the vehicles were correctly classified within the safe zone. The vast majority of the vehicles approaching at 10 km/h were classified within the safe zone, while those approaching at 20 km/h were classified within the unsafe zone. In the second session, with continuous urban background noise, 30% of the vehicles were detected and then correctly classified within safe distances. Unlike the first session, a large portion of the vehicles approaching at 20 km/h were detected and then correctly classified within the safe zone, while those approaching at 10 km/h were detected and then classified within the unsafe zone. While the ICE truck outperformed at both speeds and in both sessions, the accuracy of the BEV truck results varied depending on the session and vehicle speed. Moreover, the accuracy rates of the tasks’ results were mainly affected by whether the AVAS sound was in active mode or not, the modulation of the AVAS sound, and whether the tonal components of the BEV truck were dominant or not. These findings may provide insights into the current and future needs of designing AVAS sounds for electrified trucks.