[{"data":1,"prerenderedAt":203},["ShallowReactive",2],{"publications:\u002Fen\u002Fpublications":3},{"id":4,"title":5,"body":6,"description":10,"extension":13,"hero":14,"items":15,"locale":194,"meta":195,"navigation":196,"path":197,"seo":198,"stem":201,"__hash__":202},"publications\u002Fen\u002Fpublications.md","Publications",{"type":7,"value":8,"toc":9},"minimark",[],{"title":10,"searchDepth":11,"depth":11,"links":12},"",2,[],"md",{"heading":5},[16,24,31,38,46,54,61,68,75,82,90,97,104,112,119,126,133,139,144,151,158,165,172,180,187],{"id":17,"authors":18,"year":19,"title":20,"venue":21,"doi":22,"abstract":23},"kolahi-2025b","M. R. Kolahi, S. Mennel, J. Chambers, M. K. Patel",2025,"Energy-efficient pumping and decarbonization in thermal grids through advanced hydraulic modeling","Journal of Physics: Conference Series, 3140(2), 022006","10.1088\u002F1742-6596\u002F3140\u002F2\u002F022006","This study investigates energy-efficient pumping strategies and the decarbonization potential in the pumping section of district heating networks using advanced hydraulic modeling. Leveraging the TESSA tool, the research compares single-pipe and double-pipe configurations under three defined worst-case scenarios to assess system performance, flow behavior, and energy consumption. The study highlights the advantages of Distributed Variable Speed Pumping (DVSP) over Conventional Central Circulating Pumping (CCCP), demonstrating substantial reductions in pumping power and improved decarbonization outcomes. Results indicate that while single-pipe systems exhibit slightly higher electrothermal amplification and energy savings, double-pipe configurations offer operational benefits such as reduced reliance on heat sources and fewer required pumps. Overall, among the three scenarios, Worst-Case Scenario 1 (WCS1) emerged as the most balanced and suitable scenario for pipe sizing. In WCS1, each substation’s load is scaled relative to the district-wide peak demand, assuming all buildings reach peak load simultaneously. It consistently maintained flow velocities within the allowable range, striking a strong balance between avoiding water hammer and minimizing fouling risks.",{"id":25,"authors":26,"year":19,"title":27,"venue":28,"doi":29,"abstract":30},"chambers-2025","J. D. Chambers, M. Boegli, T. Soderstrom","5th Generation District Heating and Cooling with TESSA: pilot project in a UNESCO world heritage site","Journal of Physics: Conference Series, 3140(6), 062019","10.1088\u002F1742-6596\u002F3140\u002F6\u002F062019","District heating systems, particularly fifth-generation district heating and cooling (5GDHC), are emerging as a key solution for decarbonizing space heating and domestic hot water using renewable energy and waste heat. 5GDHC operates on an “anergy network,” a low-temperature, uninsulated pipe system that delivers both heating and cooling energy to buildings via heat pumps. This system is especially beneficial for small villages with limited space for large heat production units. When combined with long-term thermal storage solutions like shallow geothermal boreholes, 5GDHC can meet the growing demand for space cooling. However, designing these systems is data-intensive and computationally expensive due to uncertainties in energy demand, renewable resource availability, and costs. The lack of adequate design and simulation tools is a major barrier to widespread adoption. Planeto’s software TESSA addresses this by providing design automation, engineering simulations, and integrated datasets for engineers. A pilot project in Grandvaux, Switzerland, assessed the feasibility of a 5GDHC system. The village has 67 buildings with a total heat demand of 2,300 MWh\u002Fyear. The study evaluated the technical and economic feasibility of integrating decentralized energy production via heat pumps and geothermal boreholes. The 5GDHC system is suitable for villages with fewer than 2,000 inhabitants and low energy density, where traditional systems are economically unattractive. With 1,191 such municipalities in Switzerland alone, this technology holds significant potential.",{"id":32,"authors":33,"year":19,"title":34,"venue":35,"doi":36,"abstract":37},"kolahi-2025","M. R. Kolahi, J. Chambers, S. Mennel, M. K. Patel","Reducing pumping energy in thermal grids: A study on hydraulic modeling and design approaches","Energy, 327, 136410","10.1016\u002Fj.energy.2025.136410","This study investigates the hydraulic modeling of district heating and cooling systems to reduce pumping energy consumption. Key parameters such as head loss, pumping power, pump cost, and piping cost are calculated through hydraulic modeling in Python, integrated with TESSA, a validated spatial energy planning digital toolbox for district energy systems. The model first evaluates the impact of pipe size on system performance in both single-pipe and double-pipe configurations. Sensitivity analysis and Monte Carlo simulations are then applied to assess key parameters across urban, suburban, and rural cases from Switzerland. The research also compares the advantages of pressure loss and velocity limit approaches to pipe sizing, examining flow velocity limits, head losses, and the impact of undersized or oversized piping on energy efficiency and system resilience. The results indicate that oversizing pipes reduces the risk of water hammer while ensuring system adaptability for future building connections. Furthermore, total-order sensitivity analysis reveals a higher sensitivity to pipe size compared to the percentage of connected buildings. Monte Carlo simulations suggest that urban areas allow for system design with fewer initial connections compared to rural areas, offering greater flexibility for future expansion. This indicates higher adaptability for connecting additional buildings in urban areas than in rural areas.",{"id":39,"authors":40,"year":41,"title":42,"venue":43,"doi":44,"abstract":45},"speich-2024","M. Speich, J. Chambers, S. Ulli-Beer",2024,"Current and future development of thermal grids in Switzerland: an organizational perspective","Frontiers in Sustainable Cities, 6, 1379554","10.3389\u002Ffrsc.2024.1379554","Introduction Thermal grids are key to decarbonizing heating and cooling. However, their development is a complex socio-technical process. This study aims to (1) understand the thermal grid ecosystem’s development under changing political, economic and cultural frame conditions, (2) elicit actors’ perception of options for future development, and (3) identify concrete problem situations for the future development of thermal grids and describe how to address them. Methods We draw on 18 semi-structured interviews with decision-makers in utilities, municipal administrations, planning and engineering companies and intermediary organizations. Results With increased strategic importance of thermal grids, the ecosystem has been in a phase of rapid growth and professionalization in the last 10–15 years. This is reflected in a rapid increase in the number of grids, but also in capability and capacity building and greater quality standards. This transformation has been supported by a resource pool (e.g., knowledge base, capacities and capabilities, networks or decision-support tools), built partly through the value network’s activities and partly through purposeful orchestration by associations, authorities, utilities and other actors. While policy developments, energy price fluctuations and changes in customer perceptions spurred demand, thermal grid development is limited by supply-side constraints, especially a skill shortage. Four interrelated problem situations were identified: (1) Municipalities lack the resources to manage the implementation of their energy strategies. (2) The modernization of thermal grids and integration of low-carbon heat sources entails high transaction costs. (3) The implementation of thermal grids is subject to delays and quality risks, with consequences for the timely achievement of decarbonization goals. (4) Customers face uncertainty on available options, as well as on the systemic impacts of their decisions. Discussion Based on current practices, suggestions by the interviewees, as well as a comparison with the international literature, we identify four development areas to address these problem situations: (1) Empower and support municipalities. (2) Manage the scarcity of qualified workforce. (3) Leverage digital technology for the planning, realization and operation of thermal grids. (4) Pilot technological and organizational innovations together. This complements the set of previously suggested measures to support the development of thermal grids, which focused strongly on technical and regulatory aspects.",{"id":47,"authors":48,"year":49,"title":50,"venue":51,"doi":52,"abstract":53},"li-2023","X. Li, S. Yilmaz, M. K. Patel, J. Chambers",2023,"Techno-economic analysis of fifth-generation district heating and cooling combined with seasonal borehole thermal energy storage","Energy, 285, 129382","10.1016\u002Fj.energy.2023.129382","Fifth-generation district heating and cooling (5GDHC) is a promising solution to decarbonise future thermal energy systems. This paper investigates the potential of 5GDHC integrated with borehole thermal energy storage (BTES) in unlocking the synergies between heating and cooling via a bidirectional thermal network. A model for system design and operation simulation of 5GDHC is developed. In a case study, the proposed 5GDHC supplied by BTES facilitates the long-term balancing of heating and cooling demands despite the poor simultaneity between them. This enables 5GDHC to achieve overall advantages over modern heat pump driven systems, including lower levelized cost of energy, less greenhouse gas emission, higher exergy efficiency, and lower electricity peak load. One possible barrier of adopting 5GDHC is the high upfront cost, which mostly attributes to borehole drilling and booster heat pump installation. Demand scenarios with varying heating and cooling demand structures are analysed and show that the ratio of cooling to heating substantially affects the economic performance of 5GDHC coupled with BTES. When cooling to heating ratio is within the optimal range of 0.4–1.0, 5GDHC reaches lower levelized cost compared with modern heat pump driven systems and present-day gas-fired heating systems.",{"id":55,"authors":56,"year":49,"title":57,"venue":58,"doi":59,"abstract":60},"li-2023b","X. Li, J. Chambers, S. Yilmaz, M. K. Patel","Sensitivity analysis of fifth generation district heating and cooling coupled with borehole thermal energy storage with respect to cooling adoption","Journal of Physics: Conference Series, 2600(6), 062008","10.1088\u002F1742-6596\u002F2600\u002F6\u002F062008","Fifth generation district heating and cooling (5GDHC) is a promising solution for decarbonising building thermal demands, as it allows for simultaneous heating and cooling through a bi-directional network. This paper aims to investigate the general performance of 5GDHC under uncertainty. Initially, an uncertainty analysis is performed on a 5GDHC model in a case study, revealing significant variation in economic, technical, and environmental performance due to uncertain parameters. Subsequently, variance-based global sensitivity analysis is used to rank the uncertain parameters based on their impact on the economic performance of 5GDHC. The results identify cooling adoption rate, borehole pricing, and discount rate as the most influential parameters. Lastly, factors mapping demonstrates that cooling adoption rate within 0.6-0.9, low borehole costs, low discount rates, and high gas prices will drive the switch to 5GDHC. Overall, this study emphasizes the general applicability of 5GDHC.",{"id":62,"authors":63,"year":49,"title":64,"venue":65,"doi":66,"abstract":67},"chambers-2023","J. Chambers, S. Cozza, M. Patel","The GENEAP project: digitalising and automating planning of district heating and cooling","Journal of Physics: Conference Series, 2600(8), 082003","10.1088\u002F1742-6596\u002F2600\u002F8\u002F082003","The Swiss Energy Strategy 2050 implies a transformation of the provision of thermal energy services (heating and cooling) to become CO2 neutral, district heating and cooling (DHC) are an important solution, which is technically challenging to design and whose implementation entails certain risks for investment. The GENEAP (Geospatial Analysis and Planning) project developed a software that applies automation and digitalisation to address this barrier and to apply scientific research to support the work of practitioners. The software Thermal Energy System Simulation Assistant (TESSA) increases reproducibility and decreases errors, and thereby reducing overall costs. We introduced innovative algorithms for modelling heat and cooling demand, thermal energy supplies, and the cost of thermal network technologies under different retrofit and climate change scenarios. We developed graph theory-based algorithms for computationally efficient routing of thermal network pipes. The goal of the GENEAP project was to validate the models and to establish how practitioners would find value in such a tool. Through workshops and interviews we established the need for digital tools due to the rapidly increasing need for new projects, the complexity and long time frames of projects, and the limited number of available experts to do this work. We found a gap between the high level energy strategy (Plan Directeur Energetique) and the detailed engineering design stage. In between these two stages we find the need for a flexible approach that can integrate cities and societies needs into the engineering design with non-energy requirements (e.g. political context, urban constraints and opportunities, etc).",{"id":69,"authors":70,"year":49,"title":71,"venue":72,"doi":73,"abstract":74},"sasso-2023","F. Sasso, J. Chambers, M. K. Patel","Space heating demand in the office building stock: Element-based bottom-up archetype model","Energy and Buildings, 295, 113264","10.1016\u002Fj.enbuild.2023.113264","Energy efficiency in buildings is a key objective of the European energy strategy. To address the limited knowledge of the thermal performance of the non-domestic building stocks, this paper presents a bottom-up, physics-based, archetypal model derived from a large building stock database and physical characteristics from 2170 building energy performance certificates in Switzerland. The model was validated by measured energy consumption data and national statistics. Results highlight the potential for energy retrofit: most of the stock is still heated with fossil fuels (67% of the total heated area) and 40% of the total envelope surface has a poor thermal performance associated with the period before 1980. We estimate national final energy demand for heating of the office building stock (11.3 PJ\u002Fyear) and present detailed breakdown of energy by thermal loss element. Significant differences were found between archetypes related to urban settings (specific demand 50% higher in rural than in urban contexts) and age of the buildings (56% of the total demand is due to buildings constructed before 1970). The physical model highlights the impact of architectural design characteristics such as building compactness and glazed surface ratios on thermal performance. The model represents an important step for studies on optimal thermal retrofit pathways.",{"id":76,"authors":77,"year":49,"title":78,"venue":79,"doi":80,"abstract":81},"wilczynski-2023","E. J. Wilczynski, J. Chambers, M. K. Patel, E. Worrell, S. Pezzutto","Assessment of the thermal energy flexibility of residential buildings with heat pumps under various electric tariff designs","Energy and Buildings, 294, 113257","10.1016\u002Fj.enbuild.2023.113257","With the electrification of the heating sector in Europe, there is increased pressure to reduce stress to the electric grid from increased demand. Understanding the flexibility potential of the current building stock, including both efficient buildings as well as less efficient buildings, will be vital to assess the efficacy of demand-side strategies such as time-varying pricing in enabling shifts in consumer heat demand. The aim of this study is to assess the thermal flexibility potential of residential buildings with electric heating under different tariffs, and the effect of these tariffs on heating expenditure and electricity consumption. To accomplish this, a resistance–capacitance heat demand model was integrated into a linear optimization model set to find the lowest cost heating schedule for a consumer under four different tariff designs. The results indicate that time-varying tariffs can be effective in enabling shifts in the heat consumption, although the additional cost savings due to the flexibility provided by an efficient building envelope is limited (1% to 4.65% additional reduction in cost savings). The results suggest that potential flexibility is price sensitive and a function of the alignment of price and heating demand. Measures such as capacity tariffs should be considered to avoid preheating surges.",{"id":83,"authors":84,"year":85,"title":86,"venue":87,"doi":88,"abstract":89},"walch-2022","A. Walch, X. Li, J. Chambers, N. Mohajeri, S. Yilmaz, M. Patel, J. Scartezzini",2022,"Shallow geothermal energy potential for heating and cooling of buildings with regeneration under climate change scenarios","Energy, 244, 123086","10.1016\u002Fj.energy.2021.123086","Shallow ground-source heat pumps (GSHPs) are a promising technology for contributing to the decarbonisation of the energy sector. In heating-dominated climates, the combined use of GSHPs for both heating and cooling increases their technical potential, defined as the maximum energy that can be exchanged with the ground, as the re-injection of excess heat from space cooling leads to a seasonal regeneration of the ground. This paper proposes a new approach to quantify the technical potential of GSHPs, accounting for effects of seasonal regeneration, and to estimate the useful energy to supply building energy demands at regional scale. The useful energy is obtained for direct heat exchange and for district heating and cooling (DHC) under several scenarios for climate change and market penetration levels of cooling systems. The case study in western Switzerland suggests that seasonal regeneration allows for annual maximum heat extraction densities above 300 kWh\u002Fm2 at heat injection densities above 330 kWh\u002Fm2. Results also show that GSHPs may cover up to 63% of cooling and 55% of heating demand for individual GSHPs in 2050 in Switzerland, which increases to 87% and 85% if DHC is used. The regional-scale results may serve to inform decision making on strategic areas for installing GSHPs.",{"id":91,"authors":92,"year":85,"title":93,"venue":94,"doi":95,"abstract":96},"cozza-2022","S. Cozza, M. K. Patel, J. Chambers","Uncertainty in potential savings from improving energy label: A Monte Carlo study of the Swiss residential buildings","Energy and Buildings, 271, 112333","10.1016\u002Fj.enbuild.2022.112333","This paper models scenarios for energy label based retrofit targets for Switzerland’s residential building sector for 2050. It takes into account the magnitude and uncertainty in the energy performance gap (EPG) between labelled and actual energy consumption using actual energy performance data, as previous work highlighted that the EPG is not evenly distributed across different building labels. A building stock retrofit model is developed to estimate the potential energy savings from improving building performance through increasing energy label rating. A Monte Carlo analysis is applied using real EPG distribution data. The uncertainty in total energy savings is calculated for business-as-usual case and for three scenarios based on the different retrofit incentive policies of different Swiss Cantons. This allows to quantify the uncertainties in energy and emission outcomes of different policy targets arising from the variable EPG. The results show that with the business-as-usual approach it is impossible to achieve the objectives set (9.7 Mt CO 2 -eq\u002Fy vs 0.4 Mt CO 2 -eq\u002Fy by 2050). On the other hand, to reach the targets, a more aggressive policy aiming at renovating all buildings to the highest standards is necessary, that translates into a renovation rate that seems unrealistically high (3.4% per year until 2050 vs the proposed 1.4%). The contribution is to inform stakeholders designing new policies (notably the EU Renovation Wave policies) of the risk related to energy policies.",{"id":98,"authors":99,"year":85,"title":100,"venue":101,"doi":102,"abstract":103},"li-2022","X. Li, A. Walch, S. Yilmaz, M. Patel, J. Chambers","Optimal spatial resource allocation in networks: Application to district heating and cooling","Computers & Industrial Engineering, 171, 108448","10.1016\u002Fj.cie.2022.108448","District heating and cooling networks connect and distribute thermal energy resources within a network of sources and demands. While individual networks have been extensively studied, the scaling up of this technology requires the interconnection of larger sets of networks. This poses the problem of the optimal allocation of thermal resources across a spatially distributed network. Addressing this problem guarantees the efficient utilization of thermal resources and assists achieving carbon–neutral energy systems; however, previous studies have not addressed this issue. This work contributes to filling this gap by presenting an optimal spatial allocation method combining an existing spatial clustering method, transportation theory, and linear programming to maximize the allocable resources under spatial constraints. A case study shows that the proposed method is effective at handling large-scale problems. The method enables large-scale analysis of a broad range of geospatially bounded resources, especially in the application of mapping renewable energy sources to supply district heating and cooling.",{"id":105,"authors":106,"year":107,"title":108,"venue":109,"doi":110,"abstract":111},"chambers-2021","J. Chambers, M. J. S. Zuberi, K. N. Streicher, M. K. Patel",2021,"Geospatial global sensitivity analysis of a heat energy service decarbonisation model of the building stock","Applied Energy, 302, 117592","10.1016\u002Fj.apenergy.2021.117592","Decarbonising energy used for space heating and hot water is critical for reaching emission targets. Modelling of thermal energy decarbonisation becomes increasingly complex as additional technology options are included. Spatial aspects become increasingly important when considering heat transport, for example using district heating. This study develops a model for heating energy decarbonisation that makes use of a techno-economic model applied to a large geographic area (Western Switzerland) at high spatial resolution. Global sensitivity analysis is applied to quantify the variance characteristics of the model. Heating energy services provided by retrofits, decentralised heat pumps, and thermal networks are considered. Final energy demand reductions ranges of 70–80% and emissions reductions of 90% were found with levelized costs of providing the heat service of 0.14–0.22CHF\u002FkWh. High sensitivities were found with respect to efficiency parameters (retrofit potentials and seasonal performance factors). The spatial distribution of costs and sensitivities was shown to be highly variable, with a strong correlation with building density. This raises important questions, notably on equitable distribution of energy transition costs.",{"id":113,"authors":114,"year":107,"title":115,"venue":116,"doi":117,"abstract":118},"chambers-2021b","J. Chambers, M. Rittman-Frank, M. Patel","Presentation of new geospatial datasets for renewable thermal energy systems modelling in Switzerland","Journal of Physics: Conference Series, 2042(1), 012003","10.1088\u002F1742-6596\u002F2042\u002F1\u002F012003","Abstract Decarbonising heating and cooling energy buildings means going beyond individual buildings to geospatial analysis of regions and the country. This creates a need for higher resolution geospatial datasets to perform energy systems modelling. In this work we present open heating and cooling demand geospatial raster dataset produced as part of the FEEB&D research project. We discuss challenges in the production and sharing of such datasets and discuss future work towards more comprehensive databases for thermal energy modelling.",{"id":120,"authors":121,"year":107,"title":122,"venue":123,"doi":124,"abstract":125},"zuberi-2021","M. J. S. Zuberi, K. Narula, S. Klinke, J. Chambers, K. N. Streicher, M. K. Patel","Potential and costs of decentralized heat pumps and thermal networks in Swiss residential areas","International Journal of Energy Research, 45(10), 15245-15264","10.1002\u002Fer.6801","Globally, there has been an increasing trend toward electricity production from renewables, hence promoting the opportunity for the electrification of the residential heating sector as opposed to fossil fuels' combustion. Decentralized heat pumps and district heating networks could play a key role in the Swiss future approach to heating. This study provides a detailed enviro-economic assessment of the application of heat pumps and district heating systems based on renewable sources in different Swiss building archetypes on different scales. The results show that the levelized costs of heat from individual heat pumps and large-scale district heating networks (using industrial excess heat with a lower energy price than for the other energy carriers) are 7% to 20% and 65% to 75% higher than individual fossil fuel boilers for single-family houses, respectively. However, for multifamily houses, individual heat pumps, small thermal grids, and large-scale district heating networks are competitive. The district heating network coupled with a large centralized water source heat pump is found to be the most expensive solution (0.24-0.29 CHF\u002FkWh) for residential heating today. The sensitivity analysis suggests the economic feasibility of different heating technologies significantly overlaps with each other depending on the boundary conditions, hence justifying not only the mixed opinions by experts in Switzerland but also the disagreements over costs of these technologies in international literature. It can be concluded that, based on the levelized cost of heat, there are sufficient economically viable options for decarbonization and electrification of the residential heating sector. While this is an important finding for policymakers, the barriers, for example, high upfront cost, need to be addressed. Highlights Low-carbon heating technologies are investigated for residential heating supply. Levelized costs of heat from heat pumps and district heating networks are computed. Levelized costs of the heating technologies significantly overlap with each other.",{"id":127,"authors":128,"year":107,"title":129,"venue":130,"doi":131,"abstract":132},"cozza-2021","S. Cozza, J. Chambers, A. Brambilla, M. K. Patel","In search of optimal consumption: A review of causes and solutions to the Energy Performance Gap in residential buildings","Energy and Buildings, 249, 111253","10.1016\u002Fj.enbuild.2021.111253","The assessment of building performance through energy certificates is important for tracking and improving the energy efficiency of the building stock. The reliability of these assessments is critical for achieving future energy targets. However, there is evidence of a significant Energy Performance Gap (EPG) in buildings, defined as the difference between measured and calculated energy consumption. This work performs a systematic review of EPG causes and reduction strategies in the context of heating of residential buildings. It introduces the concept of “optimal” consumption, in contrast to “theoretical” (i.e. calculated with standards) and “actual” (i.e. measured) consumption, which enables a more rigorous classification of causes and potential solutions to the EPG. This review found that inaccuracies in modelling of building characteristics and occupant behaviour has been most studied by researchers. It found that many EPG reduction strategies have been proposed, which can be categorized into two groups. The first aims to improve the energy consumption calculation by correcting the standard assumptions and\u002For considering new approaches to create energy certificates. The second group focuses on improving the actual performance of the building’s energy systems, through better monitoring, maintenance, and general usage of the building. A range of practical strategies were identified, which are relevant to a range of stakeholder groups. At the same time, this work also highlights that understanding of the relative importance of EPG causes and the potential impact of the corresponding solutions is incomplete.",{"id":134,"authors":56,"year":107,"title":135,"venue":136,"doi":137,"abstract":138},"li-2021","A Monte Carlo building stock model of space cooling demand in the Swiss service sector under climate change","Energy and Buildings, 233, 110662","10.1016\u002Fj.enbuild.2020.110662","Recent trends in rising ambient air temperature have led to an increasing interest in modelling space cooling demand in countries that have traditionally not used cooling. In this study, a building stock model combined with Monte Carlo method was implemented and extended to estimate the current and future space cooling demand in the Swiss service sector. Building level analysis of the space cooling diffusion and cooling systems characteristics and their evolution under climate change was conducted. The results of this study show that the space cooling demand in the Swiss service sector is 900 ± 200 GWh\u002Fyear in 2015 and that it will increase approximately 400% in representative concentration pathway (RCP) 2.6, 500% in RCP 4.5, and 600% in RCP 8.5 by 2050. During the same period, growth in space cooling saturation rate (180–200%) is the major driver of demand growth, more than increases in total service area (35%) and cooling energy intensity (30–70%). In addition, total floor area, service area, ground floor area, and building age were identified as strong predictors of probability of presence of space cooling equipment.",{"id":140,"authors":141,"year":142,"title":143},"walch-2020","A. Walch, X. Li, R. Castello, J. D. Chambers",2020,"GIS-assisted mapping of shallow geothermal potential for space heating and cooling",{"id":145,"authors":146,"year":142,"title":147,"venue":148,"doi":149,"abstract":150},"chambers-2020","J. Chambers","Computationally scalable geospatial network and routing analysis through multi-level spatial clustering.","MethodsX, 7, 101072","10.1016\u002Fj.mex.2020.101072","Network analysis finds natural applications in geospatial information systems for a range of applications, notably for thermal grids, which are important for decarbonising thermal energy supply. These analyses are required to operate over a large range of geographic scales. This is a challenge for existing approaches, which face computational scaling challenges with the large datasets now available, such as building and road network data for an entire country. This work presents a system for geospatial modelling of thermal networks including their routing through the existing road network and calculation of flows through the network. This is in contrast to previous thermal network analysis work which could only work with simplified aggregated data.•We apply multi-level spatial clustering which enables parallelisation of work sets.•We develop algorithms and data processing pipelines for calculating network routing.•We use cluster-level caching to enable rapid evaluation of model variants.",{"id":152,"authors":153,"year":142,"title":154,"venue":155,"doi":156,"abstract":157},"streicher-2020","K. N. Streicher, S. Mennel, J. Chambers, D. Parra, M. K. Patel","Cost-effectiveness of large-scale deep energy retrofit packages for residential buildings under different economic assessment approaches","Energy and Buildings, 215, 109870","10.1016\u002Fj.enbuild.2020.109870","In this study we present a method for the assessment of the economic potential of deep energy retrofit packages for a national building stock, based on three main economic assessment approaches: 1) full investment cost and energy savings (approach FULL), 2) an approach only considering the cost of energy efficiency improvement and the related energy savings (approach IMPROVEMENT) and 3) an approach which is in line with the IMPROVEMENT approach but additionally assigns a residual value to each building element (approach DEPRECIATION). These three economic assessment approaches allow to assess the cost-effectiveness of large-scale retrofit packages according to different strategies, i.e. profit-oriented in the case of FULL, retrofitting only at end of lifetime in the case of IMPROVEMENT and pursuing a balance between environmental\u002Fenergy and economic aspects in the case of DEPRECIATION. A case study for Switzerland shows that deep energy retrofit packages offer a technical energy saving potential of 55–86% and a technical greenhouse gas abatement potential of 50% to 80% (compared to current levels). The different approaches result in economic energy saving potentials of 3% (FULL), 14% (DEPRECIATION) and 50% (IMPROVEMENT). The respective marginal levelized costs for reaching a 50% reduction in final energy demand amount to 120 CHF\u002FMWh (FULL), 40 CHF\u002FMWh (DEPRECIATION) and 1 CHF\u002FMWh (IMPROVEMENT). The results show an economic greenhouse gas saving potential of 1% (FULL), 13% (DEPRECIATION) and 65% (IMPROVEMENT) with respective marginal levelized costs for a 50% reduction of 350 CHF\u002Ft CO2eq., 90 CHF\u002Ft CO2eq. and −40 CHF\u002Ft CO2eq. The findings indicate that, without subsidies or with rather low subsidies, large-scale deep energy retrofit is economically viable only if it is part of the regular refurbishment cycle (IMPROVEMENT approach). Since full alignment with regular refurbishment cycle is not practically possible across the building stock, policy design is recommended to rather follow the DEPRECIATION approach according to which a subsidy of 40 CHF\u002FMWhsaved (or 90 CHF\u002F t CO2, avoided) would be needed in order to achieve a 50% final energy and greenhouse gas emission reduction in the building stock.",{"id":159,"authors":160,"year":142,"title":161,"venue":162,"doi":163,"abstract":164},"cozza-2020","S. Cozza, J. Chambers, C. Deb, J. Scartezzini, A. Schlüter, M. K. Patel","Do energy performance certificates allow reliable predictions of actual energy consumption and savings? Learning from the Swiss national database","Energy and Buildings, 224, 110235","10.1016\u002Fj.enbuild.2020.110235","The thermal performance gap in buildings is defined as the difference between the theoretical and the actual energy consumption for heating, and is known to undermine energy retrofit strategies and policies. This study examines the performance gap in retrofitted buildings using the Swiss Cantonal Energy Certificate for Buildings (CECB) database, using a sample of 1172 buildings for which both theoretical and actual metered consumption were known. We found an average negative performance gap of –23% for pre-retrofit buildings (actual consumption smaller than calculated) and instead a good approximation of actual consumption with theoretical consumption after retrofitting (a positive gap of 2%). A regression analysis on the energy performance certificate input parameters characterizing the building led to the conclusion that these are poor predictors of actual consumption compared to the theoretical calculation: parameters such as the energy label and the thermal proprieties of the envelope (U-values) have minor explanatory power for the actual consumption despite explaining a high degree of change in the theoretical consumption. Analysis of the indicator Energy Savings Deficit (ESD) shows an overestimation (of 37%) of the achievable savings on the basis of the theoretical consumption, whereas the prediction of savings using measured consumption before retrofit resulted in a good agreement with the actual savings (3.6% overestimation). This implies that energy savings can be estimated rather accurately by comparing the actual current consumption with the expected theoretical consumption defined by the certificate after retrofit.",{"id":166,"authors":167,"year":142,"title":168,"venue":169,"doi":170,"abstract":171},"cozza-2020b","S. Cozza, J. Chambers, M. K. Patel","Measuring the thermal energy performance gap of labelled residential buildings in Switzerland","Energy Policy, 137, 111085","10.1016\u002Fj.enpol.2019.111085","This paper addresses the thermal Energy Performance Gap (EPG), defined as the difference between a building's theoretical and actual energy consumption for thermal purposes (heating and hot water). Successful energy policies require estimates of the energy saving potential of the building stock. It is the objective of this work to analyse whether and to what extent an EPG exists in residential buildings in Switzerland. The database of the Swiss Cantonal Energy Certificate for Buildings was used, covering over 50 000 buildings. The median EPG was found to be −11% (i.e. actual consumption lower than theoretical) but varied across ratings from 12.4% (B-label) to −40.4% (G-label). Buildings with low energy ratings tend to consume significantly less than expected, while buildings with high rating tend to consume slightly more than expected. For the A-labels buildings (0.5% of the total) an EPG of −6.2% was found, suggesting that the very high-performance buildings may be more robust to the EPG. Simplified scenarios to illustrate the impact of this EPG on total consumption are presented, which highlight the challenge of meeting the Swiss Energy Strategy 2050 with a realistic renovation rate. The importance of low carbon heat supply for buildings is also discussed.",{"id":173,"authors":174,"year":175,"title":176,"venue":177,"doi":178,"abstract":179},"chambers-2019","J. Chambers, K. Narula, M. Sulzer, M. K. Patel",2019,"Mapping district heating potential under evolving thermal demand scenarios and technologies: A case study for Switzerland","Energy, 176, 682-692","10.1016\u002Fj.energy.2019.04.044","In its 2016 Heating and Cooling Strategy, the European Commission (EC) highlighted the strategic importance of heating demand for the energy demand reduction, and further noted that District Heat Networks (DHN) can play an important role in decarbonising this sector. This study applied a thermal atlas approach to map the potential for district heat networks in Switzerland. It extended existing methods with a novel approach to estimating linear thermal demand density in DHN at a national scale. DHN potential for current-generation high temperature networks as well as cutting-edge low temperature networks were compared for current building space heating and hot water demand as well as for two demand reduction scenarios. The method was tested by comparing its results to those of a local engineering study conducted for a Swiss municipality (Brig-Glis). The potential percentage of demand supplied by high temperature DHN was shown to decrease from 66% to 41% with energy saving while the potential for low temperature systems increased significantly from 2.1% to 42%. The percentage of heat demand covered by heat networks decreases less than the percentage of buildings covered, reflecting the strength of heat networks for supplying large fractions of thermal demand in geographically confined areas.",{"id":181,"authors":182,"year":175,"title":183,"venue":184,"doi":185,"abstract":186},"narula-2019","K. Narula, J. Chambers, K. N. Streicher, M. K. Patel","Strategies for decarbonising the Swiss heating system","Energy, 169, 1119-1131","10.1016\u002Fj.energy.2018.12.082","Heating and cooling contributed to about 50% of the final energy consumption in EU 28 countries. In Switzerland, about 295 PJ of heat was consumed in buildings in 2016 which emitted about 17 million tonnes CO2. However, if the Swiss nationally determined contributions (NDCs) have to be met, the country's aggregate CO2 emissions should be between 8 and 16 million tonnes in 2050. Reduction of specific space heating demand in buildings; integrating renewable energy and increased heat distribution by district heating networks (DHNs); and use of heat pumps are three strategies which have been examined for decarbonising the Swiss heating system. It is estimated that an annual reduction of 1.5%–2.5% in the aggregate heating demand for different categories of buildings would be required. DHNs would have to be expanded from 53 networks in 2016 to about 159–212 networks in 2050 to enable integration of 53–70 PJ of ambient heat. This would require 390–520 heat pumps of 2–50 MW capacity with a coefficient of performance between 3 and 4. If these strategies are implemented, it is estimated that the aggregate CO2 emissions from heating would be between 1.25 and 3.06 million tonnes by 2050 thereby significantly decarbonising the heating system.",{"id":188,"authors":189,"year":175,"title":190,"venue":191,"doi":192,"abstract":193},"schneider-2019","S. Schneider, P. Hollmuller, J. Chambers, M. Patel","A Heat Demand Load Curve Model of the Swiss National Territory","IOP Conference Series: Earth and Environmental Science, 290(1), 012107","10.1088\u002F1755-1315\u002F290\u002F1\u002F012107","Abstract This paper presents a bottom up model simulating the hourly heat demand load curve for space heating and domestic hot water production for Swiss buildings listed in the national building and dwelling register. The model was calibrated on the actual heat demand load curves of several building types and predicts the demand as function of external temperature and solar irradiation. In addition, it includes stochastic deviations to accurately reproduce the aggregated load of large building groups. Using a climatic database covering the whole Swiss territory, the model takes account of the diverse weather conditions and climate types. The aggregated simulated load curve is compared with the measurements from a large district heating network, demonstrating that key indicators such as peak load and ranked loads are very well reproduced. To disseminate the results, a GIS database was setup that estimates the aggregated heat demand load curve for any portion of the Swiss national territory. The proposed approach addresses the challenge of large territorial scale simulation using only limited information available on its building stock. The model can be easily adapted to generate load curves for other EU regions provided the required information is available for the building stock.","en",{},true,"\u002Fen\u002Fpublications",{"title":199,"description":200},"Publications - Planeto","Peer-reviewed research behind Planeto's district heating and cooling models: demand modelling, geothermal potential, network optimisation and decarbonisation.","en\u002Fpublications","Pp9mTc_bBHXMZRIhZExvb2y6pae89a_R0qQvpXEZugE",1792529650343]