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  • 1.
    Adesanya, Adewale A.
    et al.
    Energy and Environmental Analysis Group, New York State Energy Research and Development Authority (NYSERDA), Albany, NY, 12203, USA; Havenergy Consulting Inc, Albany, NY, 12203, USA.
    Sommerfeldt, Nelson
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Pearce, Joshua M.
    Department of Electrical and Computer Engineering, Ivey School of Business, University of Western Ontario, London, ON, N6A 5B9, Canada.
    Achieving 100% Renewable and Self-Sufficient Electricity in Impoverished, Rural, Northern Climates: Case Studies from Upper Michigan, USA2022In: Electricity, E-ISSN 2673-4826, Vol. 3, no 3, p. 264-296Article, review/survey (Refereed)
    Abstract [en]

    The development of 100% renewable electricity (RE) systems play a pivotal role in ensuring climate stability. Many municipalities blessed with wealth, an educated and progressive citizenry, and large RE resources, have already reached 100% RE generation. Impoverished municipalities in unwelcoming environments both politically and climatically (e.g., northern latitudes with long, dark winter conditions) appear to be incapable of transitioning to renewables. This study challenges that widespread assumption by conducting a detailed technical and economic analysis for three representative municipalities in the Western Upper Peninsula of Michigan. Each municipality is simulated with their own hourly electricity demand and climate profiles using an electrical supply system based on local wind, solar, hydropower, and battery storage. Sensitivities are run on all economic and technical variables. Results show that transition to 100% RE is technically feasible and economically viable. In all baseline scenarios, the 100% RE systems produced a levelized cost of electricity up to 43% less than the centralized utility rates, which are predominantly fueled by gas and coal. Current policies, however, prevent such self-sufficient systems from being deployed, which are not only detrimental to the global environment, but also aggravate the economic depression of such regions. Potential energy savings advance the prohibitive energy justice principle.

  • 2.
    Beltran, Francisco
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Sommerfeldt, Nelson
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Padovani, Filippo
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Rolando, Davide
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Madani Larijani, Hatef
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Solar Heat Pumps and Self-Consumption Can (and should) electricity suppliers encourage thermal storage?2022In: 2022 BuildSim Nordic, BSN 2022, EDP Sciences , 2022, article id 06005Conference paper (Refereed)
    Abstract [en]

    Heat pumps and water tanks can be used to increase PV self-consumption in buildings without any additional equipment, but there is sometimes a lack of economic incentives to maximize it that limits economic gains. Therefore, pricing conditions need to change in order to make self-consumption strategies more interesting for prosumers. This study aims at determining what, if any, unsubsidized market conditions could lead to economically motivated self-consumption control strategies with solar heat pumps. A sensitivity analysis is used on multiple pricing models based on current market conditions for a solar PV and ground source heat pump system for a single-family house in Norrköping, Sweden. The results show that control strategies aimed at maximizing self-consumption have very little impact on net costs, regardless of pricing model or variation in price. Feed-in-bonus is the most important aspect when comparing different pricing schemes, and no other sensitivity comes close.

  • 3.
    Dahl, Malin
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Ekman, Malin
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Kuldkepp, Térèse
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Sommerfeldt, Nelson
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Energy Saving Measures in Existing Swedish Buildings: Material for a book to be published by VVS Företagen2011Report (Other academic)
    Abstract [en]

    Energy efficiency in existing buildings is a primary concern for the European Union and Sweden in fighting climate change. To achieve the 20% energy reduction in buildings target by 2020, the broad base of building owners must understand the technical and financial benefits of choosing energy efficient upgrades when renovating their properties. This report is a technical supplement to the upcoming publication by the Swedish HVAC industry organization VVS Företagen, which seeks to inform their customer base about energy efficiency. Nine common Swedish apartment buildings from 1945 up to 1985 have been modeled in Design Builder building energy modeling software, with three energy saving packages applied. The energy saving packages represent a decision to choose more expensive, but more energy efficient equipment that can be installed during routine renovations. In each case, the data reported are total annual energy usage, heat balance, accumulated cash flow over a 40-year period and the internal rate of return for each package. The technical and financial performance of each building varies significantly depending on type, but most packages on most buildings have an IRR greater than 5%. While the results displayed here cannot directly represent a specific building, the data is a good resource for owners to understand what performance they can expect for their specific building. The technical information reported here is appropriate for the VVS Företagen publication.

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    Energy Saving Measures in Existing Swedish Buildings
  • 4.
    Francisco, Beltrán
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Sommerfeldt, Nelson
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Jaakko, Eskola
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Madani Larijani, Hatef
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Empirical investigation of solar photovoltaic-thermal collectors for heat pump integration2024In: Applied Thermal Engineering, ISSN 1359-4311, E-ISSN 1873-5606, Vol. 248, article id 123175Article in journal (Refereed)
    Abstract [en]

    This study empirically investigates the optimal design features of photovoltaic-thermal (PVT) collectors for integration with ground source heat pump (GSHP) systems, considering technical and economic factors. Outdoor experiments are conducted in Stockholm, Sweden, comparing five unglazed and uninsulated PVT collector designs a) Reference Sheet & Tube b) Sheet & Tube with a narrow air gap between PV and absorber plate c) Box-channel polypropylene d) Finned tube and e) Box-channel aluminum with fins at operating temperatures below ambient. The findings indicate that the box-channel aluminum design with fins, characterized by a superior combination of high zero-loss efficiency and a high U-value, emerges as the ideal PVT design for integration with ground source heat pumps, taking into account both technical and economic considerations. Despite having a relative specific thermal cost 9% higher than the reference collector, this design demonstrates the capability to generate 2,096 kWh/(m2a) of thermal energy, marking an 83.3% increase compared to the reference, with a 136% higher energy-to-mass ratio.

  • 5.
    Padovani, Filippo
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Sommerfeldt, Nelson
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration. Michigan Technol Univ, Dept Mat Sci & Engn, Houghton, MI 49931 USA.;Michigan Technol Univ, Dept Elect & Comp Engn, Houghton, MI 49931 USA..
    Longobardi, Francesca
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Pearce, Joshua M.
    Michigan Technol Univ, Dept Mat Sci & Engn, Houghton, MI 49931 USA.;Michigan Technol Univ, Dept Elect & Comp Engn, Houghton, MI 49931 USA.;Western Univ, Dept Elect & Comp Engn, London, ON, Canada..
    Decarbonizing rural residential buildings in cold climates: A techno-economic analysis of heating electrification2021In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 250, article id 111284Article in journal (Refereed)
    Abstract [en]

    Given the need for decarbonization of the heating sector and the acute need of a propane replacement in the U.S. Upper Midwest, this study quantifies the techno-economic characteristics of sustainable heating electrification in isolated rural, residential buildings in cold climates without natural gas supply. Archetypal buildings are modeled under four levels of electrification. At each electrification level, a parametric solar photovoltaic (PV) sizing analysis is performed and the total life cycle cost, renewable fraction and greenhouse gas (GHG) emissions are calculated based on the primary energy supply for each building type. Cost optimal solutions are stress-tested with multi-dimensional sensitivity analyses. The results show that the total life cycle cost favors heating electrification in all cases and combining PV with heat pumps can reduce residential building GHG emissions by up to 50% immediately. This effect will grow over time, with over 90% reduction of building emissions if renewable energy targets are met. In using primary energy and emissions along with the multi-dimensional sensitivities, this study unique demonstrates the complex techno-economic interactions of PV and heat pumps. It is concluded that electrification is an economically viable decarbonization method for cold climates both now and in the future.

  • 6. Pearce, Joshua M.
    et al.
    Sommerfeldt, Nelson
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Economics of Grid-Tied Solar Photovoltaic Systems Coupled to Heat Pumps: The Case of Northern Climates of the US and Canada2021In: Energies, E-ISSN 1996-1073, Vol. 14, no 4, article id 834Article in journal (Refereed)
    Abstract [en]

    Solar photovoltaic (PV) technology is now a profitable method to decarbonize the grid, but if catastrophic climate change is to be avoided, emissions from transportation and heating must also decarbonize. One approach to renewable heating is leveraging improvements in PV with heat pumps (HPs). To determine the potential for PV+HP systems in northern areas of North America, this study performs numerical simulations and economic analysis using the same loads and climate, but with local electricity and natural gas rates for Sault Ste. Marie, in both Canada and U.S. Ground-mounted, fixed-tilt, grid-tied PV systems are sized to match 100% of electric loads considering cases both with and without air source HPs for residences with natural gas-based heating. For the first time the results show North American residents can profitably install residential PV+HP systems, earning up to 1.9% return in the U.S. and 2.7% in Canada, to provide for all of their electric and heating needs. Returns on PV-only systems are higher, up to 4.3%; however, the PV capacities are less than half. These results suggest northern homeowners have a clear and simple method to reduce their greenhouse gas emissions by making an investment that offers a higher internal rate of return than savings accounts, CDs and GICs in both countries. Residential PV and solar-powered heat pumps can be considered 25-year investments in financial security and environmental sustainability.

  • 7.
    Poppi, Stefano
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology. KTH, Centres, SeRC - Swedish e-Science Research Centre. Dalarna University, Sweden.
    Sommerfeldt, Nelson
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Bales, Chris
    Madani, Hatef
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Lundqvist, Per
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Techno-economic review of solar heat pump systems for residential heating applications2018In: Renewable & sustainable energy reviews, ISSN 1364-0321, E-ISSN 1879-0690, Vol. 81, p. 22-32Article, review/survey (Refereed)
    Abstract [en]

    Solar heat pump systems (SHPs) have been investigated for several decades and have been proven to increase the share of renewable energy and reduce electric energy demand in residential heating applications. Many review articles have been published on the subject, however literature discussing the techno-economics of different solar technologies (thermal, photovoltaic and hybrid thermal/photovoltaic) in combination with heat pumps is lacking, and thus to directly compare the merits of different SHPs is not an easy task. The objectives of this study are: a) review the different system boundaries and the main performance indicators used for assessing energetic and economic performances; b) review techno-economic studies in the literature and identify which studies give enough information and are compatible enough for making an economic inter-comparison; c) present an economic inter-comparison based on the identified systems. The results show that there is a lack of studies including an economic assessment of solar photovoltaic and heat pump systems. Additionally, there are no consistent boundaries or approaches to the study structures, making comparisons between systems difficult. In conclusion, a standardized or broadly accepted definition of technical and economic performance for SHPs is needed. Despite this, the study has shown that there are clear trends for decreasing payback times for SHPs, both solar thermal (ST) and photovoltaic (PV), with decreasing heating degree-days and with increasing solar resource.

  • 8.
    Pourier, Christopher
    et al.
    KTH.
    Beltran, Francisco
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Sommerfeldt, Nelson
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Solar photovoltaic/thermal (PVT) technology collectors and free cooling in ground source heat pump systems2024In: Solar Energy Advances, E-ISSN 2667-1131, Vol. 4, article id 100050Article in journal (Refereed)
    Abstract [en]

    Ground source heat pump (GSHP) systems offer a low carbon heating and cooling solution for the decarbonization of buildings. As global temperatures rise, the cooling requirements of buildings will grow, even in regions where cooling systems have been historically uncommon due to their colder climate, such as Sweden. The combination of free cooling (FC) with GSHPs seems like a natural way to meet the increasing cooling needs, since the heat extracted from the building during the summer months can be injected into the ground to potentially regenerate the borehole field and enhance heat pump performance. However, a technology that is generally integrated with GSHP systems for borehole regeneration are photovoltaic/thermal collectors. This study investigates the performance of a ground source heat pump system with free cooling for a multi-family building in Stockholm, Sweden, and the interference on the free cooling capabilities of the system when photovoltaic/thermal collectors are present. The results demonstrate that the integration of PVT and FC not only maintains the cooling supply but also enhances heat pump performance, all the while reducing borehole length and land area requirements.

  • 9.
    Pressani, Michele
    et al.
    Politecn Milan, Milan, Italy..
    Sommerfeldt, Nelson
    KTH.
    Madani Larijani, Hatef
    KTH.
    Investigation Of Pv/Thermal Collector Models For Use With Ground Source Heat Pumps In Transient Simulations2017In: PROCEEDINGS OF THE 11TH ISES EUROSUN 2016 CONFERENCE / [ed] Martinez, V Gonzalez, J, International Solar Energy Society , 2017, p. 1360-1371Conference paper (Refereed)
    Abstract [en]

    Photovoltaic-thermal (PVT) collectors are commonly designed for use in domestic hot water systems, however it can be interesting to incorporate them into ground source heat pump (GSTIP) systems. Because of the historically narrow use case, many PVT models are created with a collection of assumptions which may not apply to novel collectors designed for use in PVT+GSHP systems. The aims of this study are to review existing PVT collector models for use in TRNSYS, identify any potential error sources, and test for possible improvements. Type 560 is found to be the most promising theoretical model, however two potentially limiting features are identified; the radiation absorption model and the confinement to sheet-and-tube configurations. The absorption is tested using a recreation of Type 560 in Matlab where two alternative models developed specifically for PV modules are compared. The results show a marked increase in power during low angle, low light hours, and a 14.36% increase in electrical energy and a 10.91% for the thermal energy over the course of a day with one of the models. Collector geometry is tested by creating a ID model in EES and comparing it to several geometries in Type 560. A method of packing as many tubes as possible together is shown to give comparable results as the ID model. The results of these simulations will be compared with empirical data from currently ongoing testing.

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    fulltext
  • 10.
    Schreurs, Twan
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Madani Larijani, Hatef
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Zottl, Andreas
    AIT Austrian Inst Technol, Sustainable Thermal Energy Syst, Vienna, Austria..
    Sommerfeldt, Nelson
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Zucker, Gerhard
    AIT Austrian Inst Technol, Sustainable Thermal Energy Syst, Vienna, Austria..
    Techno-economic analysis of combined heat pump and solar PV system for multi-family houses: An Austrian case study2021In: Energy Strategy Reviews, ISSN 2211-467X, E-ISSN 2211-4688, Vol. 36, article id 100666Article in journal (Refereed)
    Abstract [en]

    With the increasing amount of building renovations in Austria, the potential increases for replacing conventional national gas heating systems with heat pumps (HP) and thereby reduce CO2 emissions particularly when combined with solar photovoltaics (PV). The Austrian subsidization scheme for HP and PV systems are different for every state, creating confusion and inconstancy for potential adopters. This study provides a parametric technoeconomic analysis of PV + HP systems to identify the critical economic parameters on profitability and make policy recommendations. A case study in Vienna is modelled using demand from the Building Model Generator and black box efficiency models for the HP and PV simulated with hourly time steps. The results show that both air-source and ground source heat pumps are currently profitable with PV under current subsidy schemes. The benefit-to-cost ratio (BCR) is highly influenced by capital costs and subsidies, however natural gas prices have the greatest influence. Increasing natural gas prices by 0.01 euro/kWh, or 17%, is enough to replace all other complicated subsidies for both HP and PV. This is equivalent to a carbon emissions price of 33 euro/ton and could result in a reduction of CO2 emissions in multi-family houses by approximately 45%-60%.

  • 11.
    Sommerfeldt, Nelson
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    On the economic effects of metering schemes in community owned residential PV systems2015In: ISES Solar World Congress 2015, Daegu, South Korea, November 8-12, 2015, 2015Conference paper (Refereed)
    Abstract [en]

    Community-owned, grid-connected solar photovoltaic (PV) systems in multi-family housing offer the potential for large scale installations with favorable costs as compared to single family systems. However, traditional utility metering schemes often define boundaries which result in high sales of PV generation to the grid, lowering the economic value for the cooperative. This study explores two alternative metering schemes which better represent the interests of cooperative as a single PV owner by aggregating meters within and across buildings. Measured communal load data from a cooperative in western Sweden is combined with modeled PV generation and apartment load data to calculate the net present value (NPV) of the various meter schemes under several subsidies policies. The results show that under a traditional metering scheme, 40% of the PV generation is considered sold to the network, even though only 3% of the electricity physically leaves the buildings and none leaves the estate. Reclassifying this sold electricity as self-consumed results in an increase in NPV by as much as €60,000, which is €15,000 more than the value added by subsidies. The results of this paper are useful for community organizers, PV installers, utilities, and lawmakers interested in next generation electricity markets based on distributed generation.

  • 12.
    Sommerfeldt, Nelson
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Opportunities for large scale solar photovoltiac systems in Swedish multi-family housing2013In: 3rd International Workshop on Integration of Solar Power into Power Systems / [ed] Energynautics Gbmh, 2013Conference paper (Refereed)
    Abstract [en]

    Sweden is well known for its leadership in sustainability and energy system transformation; however solar photovoltaics have typically been left out. Recently, small residential systems have been gaining support through capital rebate subsidies and a number of utilities have begun offering modest net metering or feed-in tariff programs. There is a component of the Swedish residential sector with larger and more interesting potential; cooperative multi-family housing.

    Cooperative ownership structures are common in Sweden, accounting for nearly 20% of the total housing stock and growing at a compound rate of 2% per year. Cooperatives are considered residences except they have the possibility to install commercial sized systems up to 2.5 MWp in size. This means they can leverage greater economies of scale over detached homes making them a more interesting target for solar installations. While the system is commercial in scale, features of commercial development like complicated financing, tax structures, and renewable energy credit markets are just as daunting to a cooperative as a villa owner.

    This study is the introduction to a three year research program to be conducted from the cooperative point of view of installing solar PV. Included is a review of the current technical, economic and policy conditions in Sweden, a brief case study and proposals for future studies. Simulations are performed using the System Advisor Model from NREL. Results show that the levelized cost of energy can be competitive with retail rates, but maximized deployment may require some form of preferential metering.

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    Sommerfeldt2013_OpportunitiesForPVinSwedishMFH
  • 13.
    Sommerfeldt, Nelson
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    SOLAR PV FOR SWEDISH PROSUMERS - A COMPREHENSIVE TECHNO-ECONOMIC ANALYSIS2017In: PROCEEDINGS OF THE 11TH ISES EUROSUN 2016 CONFERENCE / [ed] Martinez, V Gonzalez, J, International Solar Energy Society , 2017, p. 1339-1347Conference paper (Refereed)
    Abstract [en]

    Like many countries around the world, Sweden is experiencing an exponential growth in PV installations, driven largely by building mounted systems. As prosumers become significant actors in the electricity market, questions about how to integrate them technically, economically, and politically are becoming more critical. A recently concluded, three-year research effort dedicated to the techno-economic analysis of PV prosumers has identified some of the major challenges for multi-family housing owners in designing PV systems in light of uncertainty in the market and policies. This paper highlights the primary results and conclusions from the project, including; PV system sizing, strategies for electricity metering to maximize revenues, a Monte Carlo analysis to understand market and policy risks, and several case studies. The overall conclusion is that PV installations can be a profitable investment in Swedish multi-family houses, however it is important to have a roof with good solar resources, a well designed and installed system, and to capture as many available economic support programs as possible. While primarily focused on multi-family houses, much of this work can be used as a practical guide for many Swedish prosumers towards developing practical systems integration solutions and increasing renewable energy usage in buildings.

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    Sommerfeldt2017_SolarPVforSwedishProsumers-Eurosun2016
  • 14.
    Sommerfeldt, Nelson
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    SOLAR PV FOR SWEDISH PROSUMERS: A COMPREHENSIVE TECHNO-ECONOMIC ANALYSIS2016In: Eurosun 2016, 2016Conference paper (Other academic)
    Abstract [en]

    Like many countries around the world, Sweden is experiencing an exponential growth in PV installations, driven largely by building mounted systems. As prosumers become significant actors in the electricity market, questions about how to integrate them technically, economically, and politically are becoming more critical. A recently concluded, three-year research effort dedicated to the techno-economic analysis of PV prosumers has identified some of the major challenges for multi-family housing owners in designing PV systems in light of uncertainty in the market and policies. This paper highlights the primary results and conclusions from the project, including; PV system sizing, strategies for electricity metering to maximize revenues, a Monte Carlo analysis to understand market and policy risks, and several case studies. The overall conclusion is that PV installations can be a profitable investment in Swedish multi-family houses, however it is important to have a roof with good solar resources, a well designed and installed system, and to capture as many available economic support programs as possible. While primarily focused on multi-family houses, much of this work can be used as a practical guide for many Swedish prosumers towards developing practical systems integration solutions and increasing renewable energy usage in buildings.

  • 15.
    Sommerfeldt, Nelson
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Solar PV in prosumer energy systems: A techno-economic analysis on sizing, integration, and risk2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In the transition towards a sustainable energy system, building mounted solar photovoltaics (PV) have unique benefits; they require no additional land and the energy is generated directly at load centers. Within residential buildings, multi-family homes (MFH) are particularly interesting because of the economies of scale and their greater potential for emissions reductions.

    This thesis identifies and describes value propositions for solar PV within Swedish multi-family houses via three branches of inquiry; system sizing optimization, quantification of investment risk, and the techno-economic potential of PV/thermal (PVT) collectors integrated with ground source heat pumps (GSHP). Underpinning these investigations is a comprehensive review of technical and economic models for solar PV, resulting in a catalogue of performance indicators and applied techniques.

    From the sizing analysis, no objective, techno-economically optimal PV system size is found without including the prosumer’s personal motives. Prioritizing return on investment results in small systems, whereas systems sized for net-zero energy can be profitable in some buildings. There is also a strong economic incentive to adopt communal electricity metering to increase self-consumption, system size, and economic return. Monte Carlo analysis is used to quantify investment uncertainty, finding that well-designed systems have an 81% chance of earning a 3% real return on investment, and even without subsidies there is a calculated 100% chance of having a positive return. PVT integrated GSHP can reduce the land needed for boreholes by up to 87% with a lower lifecycle cost than district heating, thereby broadening the heat pump market and reducing barriers to heating electrification.

    The quantitative results provide guidance for Swedish MFH owners while the methodology presents solar PV value in a more useful manner for prosumers to identify their personal motives in decision making. This approach is also useful for researchers, business leaders, and policy makers to understand the prosumer perspective and promote adoption of PV in the built environment.

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    NelsonSommerfeldt-DoctoralThesis-KTH
  • 16.
    Sommerfeldt, Nelson
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    af Klintberg, Tord
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering.
    Muyingo, Henry
    KTH, School of Architecture and the Built Environment (ABE), Real Estate and Construction Management.
    Kristoffersson, Jan
    Sustainable Innovation.
    Solceller ur flera perspektiv: Handbok för beslutsfattare2016Report (Other (popular science, discussion, etc.))
    Abstract [sv]

    För att ta fram denna handbok har flera kompetenser på KTH inom energiteknik, byggnadsteknikoch ekonomi samverkat för att bearbeta solcellsfrågan vetenskapligt ur flera perspektiv. Dennahandbok tar alltså ett multidisciplinärt grepp på solceller. Handboken vänder sig speciellt till bostadsrättsföreningar då det finns speciella problem, menäven särskilda möjligheter för dessa ägare. Många frågeställningar är dock gemensamma för fleratyper av solcellsägare, exempelvis småhusägare och flerbostadsägare.

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    fulltext
  • 17.
    Sommerfeldt, Nelson
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Beltran, Francisco
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Madani Larijani, Hatef
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    High Market Potential Applications for PVT with Heat Pumps2020In: PROCEEDINGS OF THE ISES EUROSUN 2020 CONFERENCE - 13TH INTERNATIONAL CONFERENCE ON SOLAR ENERGY FOR BUILDINGS AND INDUSTRY / [ed] Charalambides, A Streicher, W Mugnier, D, International Solar Energy Society (ISES) , 2020, p. 551-557Conference paper (Refereed)
    Abstract [en]

    Within the heat pump sector, there are applications where photovoltaic/thermal (PVT) collectors can offer greater value with lower investment costs than the current alternatives. The first is ground source heat pumps (GSHP) with under dimensioned boreholes. The second is a solar source heat pump (SSHP) where the PVT collectors are a replacement for the traditional air heat exchanger in an air source heat pump (ASHP). Complete systems models for a multi-family house are simulated in TRNSYS to determine seasonal performance factors (SPF), which are then compared technically and economically to each respective alternative. A 156 m(2) PVT array is capable of improving the SPF of a degraded GSHP by 30%, the same gains as drilling additional boreholes but at a lower cost. The SSHP with a 235 m(2) PVT array can reach an SPF of 2.6, comparable to the performance of an ASHP, but has the cost of a GSHP. Already today, PVT can economically compete with borehole drilling for GSHP and the SSHP concept shows enough market potential to warrant investment and development towards broader adoption.

  • 18.
    Sommerfeldt, Nelson
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Lemoine, Ida
    Beteendelabbet AB.
    Madani Larijani, Hatef
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    A User-Centered Design Approach to Identify Behavioral Biases in the Adoption of Solar PV by Households2021In: 6th European Conference on Behaviour Change for Energy Efficiency / [ed] Xianli Zhu and Gabriela Prata Dias, Copenhagen, 2021, p. 134-137Conference paper (Refereed)
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    BEHAVE2020-2021_SommerfeldtLemoineMadani_UserCenteredDesignInSolarPV
  • 19.
    Sommerfeldt, Nelson
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Lemoine, Ida
    Beteendelabbet AB, Stockholm, Sweden..
    Madani Larijani, Hatef
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Hide and seek: The supply and demand of information for household solar photovoltaic investment2022In: Energy Policy, ISSN 0301-4215, E-ISSN 1873-6777, Vol. 161, p. 112726-, article id 112726Article in journal (Refereed)
    Abstract [en]

    Buildings provide an ideal platform for solar photovoltaics (PV) towards sustainable development goals, and the decision to invest in PV lies predominantly with building owners. Information delivery is critical for the diffusion of innovations, and this study aims to improve the quality of information for household PV investors in Sweden. A User Journey Mapping approach is applied with a combination of semi-structured interviews and a review of online solar calculators. The results show that despite a rapid growth in the quantity of information there is still a gap between demand and supply due to the lack of clarity and trustworthiness of information. This is clearly demonstrated in the review of online calculators, which show a high variance in results. Payback time, for example, ranged from 7 to 18 years for a single test case. The information gap can be closed by creating neutral, non-commercial online information sources that focus on transparency and education where household investors can validate supplier offers and analyses. The PV industry risks eroding trust in the market, which will likely slow adoption by the early majority and hinder sustainability goals.

  • 20.
    Sommerfeldt, Nelson
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Madani, Hatef
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Improved methodology for determining the value of energy from distributed renewables using statistical analysis combined with normative scenarios2014In: Energy Procedia / [ed] J. Yan, DJ. Lee, SK. Chou, U. Desideri, H. Li, Elsevier, 2014, Vol. 61, p. 1089-1092Conference paper (Refereed)
    Abstract [en]

    The financial benefits of a distributed electric generation facility cannot be calculated without an expectation of the electricity's market value. Prediction of long-term future prices is a difficult but mandatory task, which is often reduced to constant annual prices with steady annual growth rates. This study provides a methodology for predicting electricity prices at an hourly resolution for long-term analysis, using the Swedish case as an example. It includes a statistical examination of historical data inspired by the meteorology sector to create a “typical year” of hourly price values. Future prices are calculated by applying annual rate changes to the typical year curve, using a monthly resolution to allow for seasonal variations. Rate changes are predicted using historical trends and current market conditions for near-term prices, and a normative scenario for mid- to long-term prices. The resulting methodology can be used in part or whole for any market in which historical data is available and a normative scenario created.

    Download full text (pdf)
    SommerfeldtMadani-Final
  • 21.
    Sommerfeldt, Nelson
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Madani, Hatef
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    On the use of hourly pricing in techno-economic analyses for solar photovoltaic systems2015In: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 102, no SI, p. 180-189Article in journal (Refereed)
    Abstract [en]

    The use of hourly prices in distributed photovoltaic (PV) techno-economic analysis is rare, but may become necessary as time-of-day retail pricing becomes more common. A methodology is presented for selecting an hourly price curve suitable for long-term analysis, called the typical price year (TPY), which is based on the methodology for TMY weather data. Using a techno-economic analysis with annual revenues and net present value as indicators, a TPY curve for the Swedish market is validated and then compared to 18 price simplification methods to determine the error introduced by the use of non-hourly prices. Results show that the TPY method produces a curve which accurately represents long term pricing trends, but using a static annual mean introduces minor revenue errors of 1.3%. This suggests the TPY may not be necessary in the Swedish market, but further analysis of the method is suggested for other markets.

    Download full text (pdf)
    fulltext
  • 22.
    Sommerfeldt, Nelson
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Madani, Hatef
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    REVIEW OF SOLAR PV/THERMAL PLUS GROUND SOURCE HEAT PUMP SYSTEMS FOR EUROPEAN MULTI-FAMILY HOUSES2016In: Eurosun 2016, 2016Conference paper (Refereed)
    Abstract [en]

    The combination of photovoltaic-thermal (PVT) hybrid modules with ground source heat pumps (GSHP) has the potential to increase renewable fractions of heating, cooling and power generation in buildings. The concept benefits each component in the system; the solar collector can be more efficient; collected heat can be stored in the boreholes and recovered in both short and long term; and the elevated temperatures of the boreholes improves the efficiency of the heat pump. System optimization is challenging due to the number of possible configurations, options in component designs and system control, and the close interrelation of performance between components. This study presents several system configurations which are designed to be a balance of performance, practicality, and cost. The designs are based on a state-of-the-art literature review from multiple fields (solar collectors, heat pump controls, seasonal thermal storage, and solar assisted heat pumps) and consultations with heat pump and PVT collector manufacturers.

  • 23.
    Sommerfeldt, Nelson
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Madani Larijani, Hatef
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    A Techno-Economic Comparison between PV and PVT Integrated Ground Source at Pumps for Multi-Family Houses2018In: Proceedings of the ISES Eurosun 2018 conference / [ed] Haberle, A, International Solar Energy Society, 2018, p. 901-910Conference paper (Refereed)
    Abstract [en]

    As the demand for sustainable energy technologies grows, solar photovoltaics (PV) and heat pumps are increasingly being used in buildings. Hybrid PV-thermal (PVT) collectors have been researched for decades, but have not yet had success in the market. This study combines PVT and ground source heat pumps (GSHP) in a series connection for a multi-family house, and compares the technical and economic performance to GSHP and PV+GSHP systems. A complete systems model in TRNSYS is used for the solar heat pump system, and climate and economic boundary conditions come from the Swedish market. The results show that reducing the borehole length and/or spacing with no or a limited loss of efficiency is the greatest benefit of adding PVT, however a fully sized borehole field with PV is found to be the lowest cost design option. In systems with poor efficiency and high auxiliary boiler use, the addition of PVT can be the lowest cost option but is not preferable to the PV+GSHP when space is not a limitation. The reduction in borehole field area for a given heat pump efficiency is notable since many multi-family homes cannot install GSHP due to a lack of drilling space. PVT+GSHP systems could offer a new, low-carbon heating alternative for buildings previously outside of the heat pump market.

    Download full text (pdf)
    SommerfeldtMadani2018_PVandPVT-GSHP_Eurosun2018
  • 24.
    Sommerfeldt, Nelson
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Madani Larijani, Hatef
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Ground Source Heat Pumps for Swedish Multi-Family Houses: Innovative Co-Generation and Thermal Storage Strategies2018Report (Other academic)
    Abstract [en]

    Ground source heat pumps (GSHP) have a relatively small market share in multi-family houses in part due to the limited land space available for drilling. The rapidly growing market for solar photovoltaics (PV) provides an opportunity for GSHP by acting as a secondary heat source and regenerating the ground via a heat exchanger fixed to the rear of the panel. The hybrid PV/thermal collectors, called PVT, have higher efficiencies than PV only, but also come with a significant additional cost.

    The primary objective of this research is to identify the technical and economic potential of PVT integration into multi-family house GSHP systems with borehole energy storage. This is achieved through a comprehensive technology review, dynamic complete systems modeling, construction of a detailed test site, and a qualitative assessment of commercial opportunities.

    The results show that PVT collectors can adequately support a significant undersizing of boreholes, but that it is economical only in specific conditions. One is where the heat pump shuts down due to the excessive low source temperatures and runs on the backup auxiliary heater. The savings from drilling and the increase in seasonal performance factor (SPF) is enough to justify the additional cost of the PVT. In cases where a heat pump has been running for several years and the ground temperatures are low, PVT can lift and stabilize temperatures at a lower cost than additional drilling (assuming it is possible to do additional drilling). In cases where land area is not a limitation, the highest efficiency and lowest cost option is to drill a traditionally sized borehole field and install a PV-only system.

    Integrating PVT into the GSHP is relatively simple as compared to traditional solar thermal systems. There are no changes to the hot water tank or space heating, only a heat exchanger inserted into the borehole circuit, making integration and retrofitting simple. Enabling a greater number of multi-family houses to install GSHP can reduce energy costs, primary energy demand, and carbon dioxide emissions. The form factor of modern PVT modules is the same as PV and currently qualify for government support, providing opportunities for manufactures and installers to expand their product offerings.

    PVT has shown potential to help unlock the Swedish multi-family house market for GSHP and work on detailed configurations, empirical performance, and cost reductions should be the focus of future research.

    Download full text (pdf)
    SommerfeldtMadani2018_SolarHeatPumpsForMFH-EffsysExpand
  • 25.
    Sommerfeldt, Nelson
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Madani Larijani, Hatef
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    In-depth techno-economic analysis of PV/Thermal plus ground source heat pump systems for multi-family houses in a heating dominated climate2019In: Solar Energy, ISSN 0038-092X, E-ISSN 1471-1257, Vol. 190, p. 44-62Article in journal (Refereed)
    Abstract [en]

    The electrification of buildings is a promising pathway to the decarbonization of cities. This is a parametric study of the technical and economic performance of ground source heat pump (GSHP) systems with series connected solar PV/thermal (PVT) collectors. The focus is on multi-family houses (MFH) in the heating dominated climate of Sweden, where land restrictions for boreholes or noise restrictions on air heat exchangers limit the heat pump market. System efficiency and lifecycle cost results are generated using a holistic and detailed systems model in TRNSYS with 20 year simulations. The results show that PVT can reduce borehole length by 18% or spacing by 50% while maintaining an equivalent seasonal performance factor to systems without PVT. The cost for PVT + GSHP systems is higher than a traditionally designed PV + GSHP, however this does not take into account the value of the land area saved by PVT, which can be up to 89%. The reduction in land enabled by PVT has the potential to increase penetration of GSHP in MFH and promote solar energy diffusion in high latitude markets.

  • 26.
    Sommerfeldt, Nelson
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Madani Larijani, Hatef
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Revisiting the techno-economic analysis process for building-mounted, grid-connected solar photovoltaic systems: Part one - Review2017In: Renewable & sustainable energy reviews, ISSN 1364-0321, E-ISSN 1879-0690, Vol. 74, p. 1379-1393Article, review/survey (Refereed)
    Abstract [en]

    The market for solar photovoltaic systems is growing rapidly into a mature industry, while at the same time policies which have spurred the growth (e.g. feed-in tariffs or net metering) are beginning to fade away. These policies made techno-economic studies relatively simple for engineers, analysts, and owners, however investing in a deregulated market requires more advanced tools than the traditional engineering economics which dominate the literature. The objective of part one in this paper is to catalogue and critique the range of methods and models relevant to techno-economic analysis for PV systems in the context of distributed, grid-connected buildings. This is accomplished by; developing a system modeling framework for prosumer PV investment analysis, reviewing relevant energy, economics, and finance literature to identify mathematical models which can be applied, and cataloging the use of the reviewed techniques in the relevant literature. Also included is a qualitative discussion of the benefits and practicality of the review techniques, where Monte Carlo analysis is highlighted as an exemplary method. This review is useful as a reference for analysts, researchers, and engineers developing PV integration solutions for building energy systems in a post early adopter PV market.

  • 27.
    Sommerfeldt, Nelson
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Madani Larijani, Hatef
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Revisiting the techno-economic analysis process for building-mounted, grid-connected solar photovoltaic systems: Part two - Application2017In: Renewable & sustainable energy reviews, ISSN 1364-0321, E-ISSN 1879-0690, Vol. 74, p. 1394-1404Article, review/survey (Refereed)
    Abstract [en]

    Part One in this two part paper identified Monte Carlo analysis as an improved approach over traditional deterministic techno-economic methods for solar PV prosumers in deregulated markets. In this paper a novel Monte Carlo methodology is described and demonstrated through a case study for the Swedish residential sector, which includes a review of relevant market, climate, and policy conditions, their use in determining inputs, and the probabilistic results. The probability of profitability (PoP) is introduced as an indicator in conjunction with result distributions. The results show that under current policy conditions, Swedish PV investors with well positioned buildings have a 71% chance of making a 3% real return on investment, and virtually no chance of losing their original investment. Without subsidies the PoP drops to 8%. In none of the simulated cases was any of the original investment lost. The PoP is most sensitive to the capital subsidy and the uncertainty of market based, long-term support is less critical to the chances of a successful investment. Given the current market conditions, Swedish PV prosumers can expect a return on investment. The decision to install will also depend on the probability of achieving their desired profitability, which Monte Carlo analysis quantifies well.

  • 28.
    Sommerfeldt, Nelson
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Muyingo, Henry
    KTH, School of Architecture and the Built Environment (ABE), Real Estate and Construction Management, Building and Real Estate Economics.
    Lessons in community owned PV from swedish multi-family housing cooperatives2015In: 31st European Photovoltaic Solar Energy Conference and Exhibition, 2015, p. 2745-2750Conference paper (Refereed)
    Abstract [en]

    With increasing population shifts to urban areas and demands for post-war energy efficient renovationsacross Europe, solar photovoltaic (PV) deployment in multi-family housing will play an increasingly important roletowards meeting renewable energy, climate, and sustainability goals. This paper describes the stories of threeSwedish residential cooperatives who have installed large-scale PV systems across multiple buildings on their estates.In all cases, reduced operating costs were the original primary motivator; however unforeseen cost increases, changesin policy, and excess supply in the electricity market have made economic success less likely than originallyexpected. Regardless, the owners consider their projects a success due in part to short term social and long-termenvironmental benefits, which were originally less important and difficult to quantify. We can conclude thatcommunity owned PV offers more than just economic benefits, and Sweden’s unique ownership and managementstructure of residential cooperatives can offer insights towards increased deployment in other nations in Europe.

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    fulltext
  • 29.
    Sommerfeldt, Nelson
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Muyingo, Henry
    KTH, School of Architecture and the Built Environment (ABE), Real Estate and Construction Management.
    af Klintberg, Tord
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering.
    Björk, Folke (Commentator for written text)
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering.
    Madani, Hatef (Contributor)
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Photovoltaic Systems for Swedish Prosumers: A technical and economic analysis focused on cooperative multi-family housing2016Report (Other academic)
    Abstract [en]

    This report is designed to be a comprehensive information resource for Swedish prosumers considering an investment in solar PV systems. The target audience are multi-family cooperative houses, however much of the information is applicable to other building owners and solar energy more broadly. The primary question to be answered; is a rooftop PV investment profitable in Sweden? Naturally there are many variables that can affect the answer; therefore a Monte Carlo methodology is used to convert the uncertainties into risks, where the results can be presented as probabilities rather than a vast collection of sensitivity analyses. Several policy scenarios are tested, where the relative impact of each current program on profitability can be seen.

    Download full text (pdf)
    fulltext
  • 30.
    Sommerfeldt, Nelson
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Ollas, Patrik
    Research Institutes of Sweden.
    Reverse Engineering Prototype Solar PV/Thermal Collector Properties from Empirical Data for Use in TRNSYS Type 5602017In: ISES Solar World Congress and IEA Solar Heating and Cooling Conference 2017, Abu Dhabi, UAE, October 29 - November 2, 2017, 2017, p. 1121-1132Conference paper (Refereed)
    Abstract [en]

    Using the known physical characteristics of a prototype photovoltaic-thermal (PVT) collector components and raw test data from a prematurely terminated ISO 9806 test, the objective of this study is to reverse engineer a thermal resistance value for the heat exchanger assembly for use in the theoretical TRNSYS model Type 560. Modeling is done using both TRNSYS as well as commercial heat transfer software TAITherm. Performance is measured by the mean absolute error and correlation of the outlet temperature and thermal power, as well as the differences in total thermal energy generated. The results show a thermal resistance of 0.005 to 0.010 m2 K W-1 in TAITherm and 0.010 to 0.040 m2 K W-1 in Type 560. TAITherm gives better statistical indicators which is likely due to the inclusion of thermal mass in the model. The results have informed prototype development and can be used in further systems modeling.

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    fulltext
  • 31.
    Sommerfeldt, Nelson
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration. Michigan Technol Univ, Dept Mat Sci & Engn, Houghton, MI 49931 USA..
    Pearce, Joshua M.
    Michigan Technol Univ, Dept Mat Sci & Engn, Houghton, MI 49931 USA.;Western Univ, Ivey Business Sch, Dept Elect & Comp Engn, London, ON, England..
    Can grid-tied solar photovoltaics lead to residential heating electrification?: A techno-economic case study in the midwestern US2023In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 336, article id 120838Article in journal (Refereed)
    Abstract [en]

    This study aims to quantify the techno-economic potential of using solar photovoltaics (PV) to support heat pumps (HP) towards the replacement of natural gas heating in a representative North American residence from a house owner's point of view. For this purpose, simulations are performed on: (1) a residential natural gas-based heating system and grid electricity, (2) a residential natural gas-based heating system with PV to serve the electric load, (3) a residential HP system with grid electricity, and (4) a residential HP+PV system. Detailed descriptions are provided along with a comprehensive sensitivity analysis for identifying specific boundary conditions that enable lower total life cycle cost. The results show that under typical inflation conditions, the lifecycle cost of natural gas and reversable, air-source heat pumps are nearly identical, however the electricity rate structure makes PV costlier. With higher rates of inflation or lower PV capital costs, PV becomes a hedge against rising prices and encourages the adoption of HPs by also locking in both electricity and heating cost growth. The real internal rate of return for such prosumer technologies is 20x greater than a long-term certificate of deposit, which demonstrates the additional value PV and HP technologies offer prosumers over comparably secure investment vehicles while making substantive reductions in carbon emissions. Using the large volume of results generated, impacts on energy policy are discussed, including rebates, net-metering, and utility business models.

  • 32.
    Tóth, Martos
    et al.
    KTH.
    Sommerfeldt, Nelson
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    PV self-consumption prediction methods using supervised machine learning2022In: 2022 BuildSim Nordic, BSN 2022, EDP Sciences , 2022, article id 02003Conference paper (Refereed)
    Abstract [en]

    The increased prevalence of photovoltaic (PV) self-consumption policies across Europe and the world place an increased importance on accurate predictions for life-cycle costing during the planning phase. This study presents several machine learning and regression models for predicting self-consumption, trained on a variety of datasets from Sweden. The results show that advanced ML models have an improved performance over simpler regressions, where the highest performing model, Random Forest, has a mean average error of 1.5 percentage points and an R2 of 0.977. Training models using widely available typical meteorological year (TMY) climate data is also shown to introduce small, acceptable errors when tested against spatially and temporally matched climate and load data. The ability to train the ML models with TMY climate data makes their adoption easier and builds on previous work by demonstrating the robustness of the methodology as a self-consumption prediction tool. The low error and high R2 are a notable improvement over previous estimation models and the minimal input data requirements make them easy to adopt and apply in a wide array of applications.

1 - 32 of 32
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