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To generate performance predictions of borehole thermal energy storage (BTES) systems for both seasonal and short-term storage of industrial excess heat, e.g., from high to low production hours, models are needed that can handle the short-term effects. In this study, the first and largest industrial BTES in Sweden, applying intermittent heat injection and extraction down to half-day intervals, was modelled in the IDA ICE 4.8 environment and compared to three years of measured storage performance. The model was then used in a parametric study to investigate the change in performance of the storage from e.g., borehole spacing and storage supply flow characteristics at heat injection. For the three-year comparison, predicted and measured values for total injected and extracted energy differed by less than 1% and 3%, respectively and the mean relative difference for the storage temperatures was 4%, showing that the performance of large-scale BTES with intermittent heat injection and extraction can be predicted with high accuracy. At the actual temperature of the supply flow during heat injection, 40 °C, heat extraction would not exceed approximately 100 MWh/year for any investigated borehole spacing, 1–8 m. However, when the temperature of the supply flow was increased to 60–80 °C, 1400–3100 MWh/year, also dependent on the flow rate, could be extracted at the spacing yielding the highest heat extraction, which in all cases was 3–4 m.
Emil Nilsson; Patrik Rohdin. Empirical Validation and Numerical Predictions of an Industrial Borehole Thermal Energy Storage System. Energies 2019, 12, 2263 .
AMA StyleEmil Nilsson, Patrik Rohdin. Empirical Validation and Numerical Predictions of an Industrial Borehole Thermal Energy Storage System. Energies. 2019; 12 (12):2263.
Chicago/Turabian StyleEmil Nilsson; Patrik Rohdin. 2019. "Empirical Validation and Numerical Predictions of an Industrial Borehole Thermal Energy Storage System." Energies 12, no. 12: 2263.
This study addresses the life cycle costs (LCC) of energy renovation, and the demolition and construction of a new building. A comparison is made between LCC optimal energy renovations of four different building types with thermal performance, representing Swedish constructions from the 1940s, 1950s, 1960s, and 1970s, as well as the demolition of the building and construction of a new building that complies with the Swedish building code. A Swedish multi-family building from the 1960s is used as a reference building. LCC optimal energy renovations are identified with energy saving targets ranging between 10% and 70%, in addition to the lowest possible life cycle cost. The analyses show that an ambitious energy renovation is not cost-optimal in any of the studied buildings, if achieving the lowest LCC is the objective function. The cost of the demolition and construction of a new building is higher compared to energy renovation to the same energy performance. The higher rent in new buildings does not compensate for the higher cost of new construction. A more ambitious renovation is required in buildings that have a shape factor with a high internal volume to heated floor area ratio.
Lina La Fleur; Patrik Rohdin; Bahram Moshfegh. Energy Renovation versus Demolition and Construction of a New Building—A Comparative Analysis of a Swedish Multi-Family Building. Energies 2019, 12, 2218 .
AMA StyleLina La Fleur, Patrik Rohdin, Bahram Moshfegh. Energy Renovation versus Demolition and Construction of a New Building—A Comparative Analysis of a Swedish Multi-Family Building. Energies. 2019; 12 (11):2218.
Chicago/Turabian StyleLina La Fleur; Patrik Rohdin; Bahram Moshfegh. 2019. "Energy Renovation versus Demolition and Construction of a New Building—A Comparative Analysis of a Swedish Multi-Family Building." Energies 12, no. 11: 2218.
A hydronic pavement system (HPS) is an alternative method to clear snow and ice, which avoids the use of salt, sand, and fossil fuel in conventional snow clearance, and minimizes the risk of accidents. The aim is to analyze the performance of different control strategies for a 35,000 m2 HPS utilizing heat from a district heating and cooling (DHC) system. The key performance indicators are (1) energy performance of the HPS, and (2) primary energy use, (3) electricity production and (4) greenhouse gas (GHG) emissions from the DHC system. The methodology uses a simulation model of the HPS and an optimization model of the DHC system. Three operational strategies are analyzed: A reference scenario based on the current control strategy, and scenarios where the HPS is shut down at temperatures below −10 °C and −5 °C. The study shows that the DHC return temperature is suitable for use. By operational strategies, use during peak demand in the DHC system can be avoided, resulting in reduced use of fossil fuel. Moreover, the energy use of the HPS could be reduced by 10% and the local GHG emissions by 25%. The study emphasizes that the HPS may have positive effects on global GHG emissions, as it enables electricity production from renewable resources.
Stefan Blomqvist; Shahnaz Amiri; Patrik Rohdin; Louise Ödlund. Analyzing the Performance and Control of a Hydronic Pavement System in a District Heating Network. Energies 2019, 12, 2078 .
AMA StyleStefan Blomqvist, Shahnaz Amiri, Patrik Rohdin, Louise Ödlund. Analyzing the Performance and Control of a Hydronic Pavement System in a District Heating Network. Energies. 2019; 12 (11):2078.
Chicago/Turabian StyleStefan Blomqvist; Shahnaz Amiri; Patrik Rohdin; Louise Ödlund. 2019. "Analyzing the Performance and Control of a Hydronic Pavement System in a District Heating Network." Energies 12, no. 11: 2078.
Borehole thermal energy storage (BTES) is a technology which allows for both seasonal and short-to-medium-term storage of thermal energy and which can be used for both heating and cooling. This makes BTES of special interest to many industries. However, post-implementation evaluations of large-scale industrial BTES are scarce. The BTES at Xylem's production plant in Emmaboda, Sweden is one of the world's largest BTES systems for storage of industrial excess heat. In this paper, the BTES at Emmaboda was evaluated with respect to how it was integrated and how it has performed during its first seven years of operation. The BTES consists of 140 boreholes, 150 m deep, and heat for storage is mainly recovered from two high-temperature ovens and the foundry ventilation air. So far, the highest heat extraction and BTES efficiency (19%) took place in the storage system's sixth full year of operation, when roughly 2200 MWh and 400 MWh were injected into and extracted from the storage respectively. One main reason extraction is not higher is that the quantities and/or the quality of the excess heat for storage are lower than estimated, thus hindering the storage from reaching the necessary temperatures for heat extraction.
Emil Nilsson; Patrik Rohdin. Performance evaluation of an industrial borehole thermal energy storage (BTES) project – Experiences from the first seven years of operation. Renewable Energy 2019, 143, 1022 -1034.
AMA StyleEmil Nilsson, Patrik Rohdin. Performance evaluation of an industrial borehole thermal energy storage (BTES) project – Experiences from the first seven years of operation. Renewable Energy. 2019; 143 ():1022-1034.
Chicago/Turabian StyleEmil Nilsson; Patrik Rohdin. 2019. "Performance evaluation of an industrial borehole thermal energy storage (BTES) project – Experiences from the first seven years of operation." Renewable Energy 143, no. : 1022-1034.
In Sweden, 90% of multifamily buildings utilize district heat and a large portion is in need of renovation. The aim is to analyze the impact of renovating a multifamily building stock in a district heating and cooling system, in terms of primary energy savings, peak power demands, electricity demand and production, and greenhouse gas emissions on local and global levels. The study analyzes scenarios regarding measures on the building envelope, ventilation, and substitution from district heat to ground source heat pump. The results indicate improved energy performance for all scenarios, ranging from 11% to 56%. Moreover, the scenarios present a reduction of fossil fuel use and reduced peak power demand in the district heating and cooling system ranging from 1 MW to 13 MW, corresponding to 4–48 W/m2 heated building area. However, the study concludes that scenarios including a ground source heat pump generate significantly higher global greenhouse gas emissions relative to scenarios including district heating. Furthermore, in a future fossil-free district heating and cooling system, a reduction in primary energy use will lead to a local reduction of emissions along with a positive effect on global greenhouse gas emissions, outperforming measures with a ground source heat pump.
Stefan Blomqvist; Lina La Fleur; Shahnaz Amiri; Patrik Rohdin; Louise Ödlund (Former Trygg). The Impact on System Performance When Renovating a Multifamily Building Stock in a District Heated Region. Sustainability 2019, 11, 2199 .
AMA StyleStefan Blomqvist, Lina La Fleur, Shahnaz Amiri, Patrik Rohdin, Louise Ödlund (Former Trygg). The Impact on System Performance When Renovating a Multifamily Building Stock in a District Heated Region. Sustainability. 2019; 11 (8):2199.
Chicago/Turabian StyleStefan Blomqvist; Lina La Fleur; Shahnaz Amiri; Patrik Rohdin; Louise Ödlund (Former Trygg). 2019. "The Impact on System Performance When Renovating a Multifamily Building Stock in a District Heated Region." Sustainability 11, no. 8: 2199.
Improved energy efficiency in the building sector is a central goal in the European Union and renovation of buildings can significantly improve both energy efficiency and indoor environment. This paper studies the perception of indoor environment, modelled indoor climate and heat demand in a building before and after major renovation. The building was constructed in 1961 and renovated in 2014. Insulation of the façade and attic and new windows reduced average U-value from 0.54 to 0.29 W/m2·K. A supply and exhaust ventilation system with heat recovery replaced the old exhaust ventilation. Heat demand was reduced by 44% and maximum supplied heating power was reduced by 38.5%. An on-site questionnaire indicates that perceived thermal comfort improved after the renovation, and the predicted percentage dissatisfied is reduced from 23% to 14% during the heating season. Overall experience with indoor environment is improved. A sensitivity analysis indicates that there is a compromise between thermal comfort and energy use in relation to window solar heat gain, internal heat generation and indoor temperature set point. Higher heat gains, although reducing energy use, can cause problems with high indoor temperatures, and higher indoor temperature might increase thermal comfort during heating season but significantly increases energy use.
Lina La Fleur; Patrik Rohdin; Bahram Moshfegh. Energy Use and Perceived Indoor Environment in a Swedish Multifamily Building before and after Major Renovation. Sustainability 2018, 10, 766 .
AMA StyleLina La Fleur, Patrik Rohdin, Bahram Moshfegh. Energy Use and Perceived Indoor Environment in a Swedish Multifamily Building before and after Major Renovation. Sustainability. 2018; 10 (3):766.
Chicago/Turabian StyleLina La Fleur; Patrik Rohdin; Bahram Moshfegh. 2018. "Energy Use and Perceived Indoor Environment in a Swedish Multifamily Building before and after Major Renovation." Sustainability 10, no. 3: 766.
Linn Liu; Patrik Rohdin; Bahram Moshfegh. Investigating cost-optimal refurbishment strategies for the medieval district of Visby in Sweden. Energy and Buildings 2018, 158, 750 -760.
AMA StyleLinn Liu, Patrik Rohdin, Bahram Moshfegh. Investigating cost-optimal refurbishment strategies for the medieval district of Visby in Sweden. Energy and Buildings. 2018; 158 ():750-760.
Chicago/Turabian StyleLinn Liu; Patrik Rohdin; Bahram Moshfegh. 2018. "Investigating cost-optimal refurbishment strategies for the medieval district of Visby in Sweden." Energy and Buildings 158, no. : 750-760.
Lina La Fleur; Bahram Moshfegh; Patrik Rohdin. Measured and predicted energy use and indoor climate before and after a major renovation of an apartment building in Sweden. Energy and Buildings 2017, 146, 98 -110.
AMA StyleLina La Fleur, Bahram Moshfegh, Patrik Rohdin. Measured and predicted energy use and indoor climate before and after a major renovation of an apartment building in Sweden. Energy and Buildings. 2017; 146 ():98-110.
Chicago/Turabian StyleLina La Fleur; Bahram Moshfegh; Patrik Rohdin. 2017. "Measured and predicted energy use and indoor climate before and after a major renovation of an apartment building in Sweden." Energy and Buildings 146, no. : 98-110.
Highlights•Linköping Regional PV roof potential is 19, 43 or 88% of present electricity demand.•Spatial-time distribution feasibility study of dynamic load matching of PV supply.•Altering Tilt and azimuth of PV panels can spread PV supply over the hours day season. AbstractElectricity production by PV is growing world-wide, and grid parity of PV-electricity can be found in many countries, even in low sunlight countries, such as Sweden (at latitude 58°). High installation-rate of PV-systems poses a challenge to the grid-operator. Building-integrated PV-supply potential analysis was performed for Linköping municipality in Sweden based on GIS-data for all the buildings in the municipality. The Linköping model provides a high spatial resolution (>180 000 buildings). The data are sorted based on azimuth and tilt, categorized in steps of 10°, and then used to construct hourly power supply data. The supply data are fed into the existing electricity load-profile of Linköping municipality. The strength and novelty of the method is that it provides the possibility of varying the installation-rate in different spatial directions to better match the load-profile.The results indicate a solar supply-rate of 19, 43 and 88% respectively if using the tilted roofs (>900 kWh/m2 × yr), the flat-roofs optimized with tilted panels for a winter solar supply and the fully available PV-area on existing buildings (8.1 km2). Nevertheless, in approximately 70, 1400 and >3000 h/yr, respectively, surplus-power is created, which could be used to match a future load in a wider electro-mobility scenario. Graphical abstract
Andreas Molin; Simon Schneider; Patrik Rohdin; Bahram Moshfegh. Assessing a regional building applied PV potential – Spatial and dynamic analysis of supply and load matching. Renewable Energy 2016, 91, 261 -274.
AMA StyleAndreas Molin, Simon Schneider, Patrik Rohdin, Bahram Moshfegh. Assessing a regional building applied PV potential – Spatial and dynamic analysis of supply and load matching. Renewable Energy. 2016; 91 ():261-274.
Chicago/Turabian StyleAndreas Molin; Simon Schneider; Patrik Rohdin; Bahram Moshfegh. 2016. "Assessing a regional building applied PV potential – Spatial and dynamic analysis of supply and load matching." Renewable Energy 91, no. : 261-274.
This work uses computational models to study the effects of confluence and jet-to-jet interactions for inline matrices of confluent round jets. In total, 12 different confluent jet arrangements, having various jet array sizes and dimensionless jet spacing, S/d0, have been investigated. The array size varies from 6 × 6 to 10 × 10 jets, while S/d0 varies between 1.75≤S/d0≤4.0. The Reynolds number, based on the nozzle exit diameter, is between 2200 and 6600. The results show that both jet spacing and jet array size largely influence the jet-to-jet interactions and flow field development in confluent jet arrays. The jet interactions in the investigated setups result in regions of negative static pressure between jets, jet deformation, high spanwise velocity, and jet displacement. Generally, smaller jet spacing and larger array size result in stronger influence of jet interactions. After the jets have combined, the confluent jets form a zone with constant maximum streamwise velocity and decay of turbulence intensity, called a confluent core zone (CCZ). During the CCZ, the combined jet will have asymmetric spreading rates leading to axis-switching. The entrainment rate of the CCZ is constant, but the volumetric flow rate of the combined jet is substantially affected by the degree of entrainment before the jets have combined.
Klas Svensson; Patrik Rohdin; Bahram Moshfegh. On the Influence of Array Size and Jet Spacing on Jet Interactions and Confluence in Round Jet Arrays. Journal of Fluids Engineering 2016, 138, 081206 .
AMA StyleKlas Svensson, Patrik Rohdin, Bahram Moshfegh. On the Influence of Array Size and Jet Spacing on Jet Interactions and Confluence in Round Jet Arrays. Journal of Fluids Engineering. 2016; 138 (8):081206.
Chicago/Turabian StyleKlas Svensson; Patrik Rohdin; Bahram Moshfegh. 2016. "On the Influence of Array Size and Jet Spacing on Jet Interactions and Confluence in Round Jet Arrays." Journal of Fluids Engineering 138, no. 8: 081206.
Purpose – This paper presents an approach where a survey study is combined with energy and indoor environment auditing in the built environment. The combination of methods presented in this paper is one way to obtain a wider perspective on the indoor environment and energy use and also let the people in the building voice their comments on the indoor environment. This is arguably even more important in historic buildings where many of the physical properties are to a higher degree unknown when compared with conventional buildings. The purpose of the paper is to report the experiences from this research project. Design/methodology/approach – A combination of energy and indoor environment auditing and standardized occupant surveys. Findings – The main findings in the paper are related to the good agreement between results from standardized occupant surveys and physical measurements. The possibility to triangulate problems related to poor indoor conditions was shown to be one main advantage of the combined methodology presented in the paper. A standardized survey approach also allows benchmarking, in this case with two groups representing “average” buildings as well as a group representing well-functioning buildings. The use of records from building key cards was also shown to be an effective way of keeping track of activity in the building and thereby distribute internal gains. In addition, the paper reports a linear correlation between activity level and electricity use. Originality/value – The paper shows an effective way to investigate the performance, in terms of energy use as well as indoor environment, of historic buildings in use. This type of approach could benefit property owners, as it both allows benchmarking as well as investigating individual properties before, e.g., a refurbishment.
Patrik Rohdin; Mariusz Dalewski; Bahram Moshfegh. Combining a survey approach and energy and indoor environment auditing in historic buildings. Journal of Engineering, Design and Technology 2016, 14, 182 -195.
AMA StylePatrik Rohdin, Mariusz Dalewski, Bahram Moshfegh. Combining a survey approach and energy and indoor environment auditing in historic buildings. Journal of Engineering, Design and Technology. 2016; 14 (1):182-195.
Chicago/Turabian StylePatrik Rohdin; Mariusz Dalewski; Bahram Moshfegh. 2016. "Combining a survey approach and energy and indoor environment auditing in historic buildings." Journal of Engineering, Design and Technology 14, no. 1: 182-195.
Tor Broström; Petra Eriksson; Linn Liu; Patrik Rohdin; Fredrik Ståhl; Bahram Moshfegh. A Method to Assess the Potential for and Consequences of Energy Retrofits in Swedish Historic Buildings. The Historic Environment: Policy & Practice 2014, 5, 150 -166.
AMA StyleTor Broström, Petra Eriksson, Linn Liu, Patrik Rohdin, Fredrik Ståhl, Bahram Moshfegh. A Method to Assess the Potential for and Consequences of Energy Retrofits in Swedish Historic Buildings. The Historic Environment: Policy & Practice. 2014; 5 (2):150-166.
Chicago/Turabian StyleTor Broström; Petra Eriksson; Linn Liu; Patrik Rohdin; Fredrik Ståhl; Bahram Moshfegh. 2014. "A Method to Assess the Potential for and Consequences of Energy Retrofits in Swedish Historic Buildings." The Historic Environment: Policy & Practice 5, no. 2: 150-166.
This paper presents experiences from a recently built area with passive houses in Linkoping, Sweden and compares them with conventional buildings, mainly from an indoor environment perspective, but also based on energy use. The built area consists of 39 recently constructed terraced houses, of which nine are built according to the passive house standard. The aspects of thermal comfort as well as local discomfort are studied. The methodology is based on on-site measurements and two types of simulations - CFD and Building Energy Simulation. In addition a post-occupancy evaluation was made using a standardized questionnaire to relate the occupants perception of the indoor environment one year after the buildings were completed. The thermal comfort for these newly built passive houses is well within the limits in the local building code. However, some interesting findings related to local comfort such as cold floors are found in the post-occupancy evaluation as well as in the predictions. The occupants of the passive houses experience cold floors to a higher degree than in the conventional buildings. It was also shown that there are a higher number of complaints related to high temperatures during summer in the passive houses. It is worth noting that the buildings do not have external shading installed by default. The effect of varying temperatures was also observed in the passive houses to a higher degree than in the more conventional buildings, especially related to cooking and other heat-generating activities, which is normal in a more well insulated and airtight building
Patrik Rohdin; Andreas Molin; Bahram Moshfegh. Experiences from nine passive houses in Sweden – Indoor thermal environment and energy use. Building and Environment 2014, 71, 176 -185.
AMA StylePatrik Rohdin, Andreas Molin, Bahram Moshfegh. Experiences from nine passive houses in Sweden – Indoor thermal environment and energy use. Building and Environment. 2014; 71 ():176-185.
Chicago/Turabian StylePatrik Rohdin; Andreas Molin; Bahram Moshfegh. 2014. "Experiences from nine passive houses in Sweden – Indoor thermal environment and energy use." Building and Environment 71, no. : 176-185.
Patrik Thollander; Patrik Rohdin; Bahram Moshfegh; Magnus Karlsson; Mats Söderström; Louise Trygg. Energy in Swedish industry 2020 – current status, policy instruments, and policy implications. Journal of Cleaner Production 2013, 51, 109 -117.
AMA StylePatrik Thollander, Patrik Rohdin, Bahram Moshfegh, Magnus Karlsson, Mats Söderström, Louise Trygg. Energy in Swedish industry 2020 – current status, policy instruments, and policy implications. Journal of Cleaner Production. 2013; 51 ():109-117.
Chicago/Turabian StylePatrik Thollander; Patrik Rohdin; Bahram Moshfegh; Magnus Karlsson; Mats Söderström; Louise Trygg. 2013. "Energy in Swedish industry 2020 – current status, policy instruments, and policy implications." Journal of Cleaner Production 51, no. : 109-117.