kth.sePublications
Change search
Link to record
Permanent link

Direct link
Alternative names
Publications (10 of 236) Show all publications
Wolde, M. G., Khatiwada, D., Bekele, G. & Palm, B. (2024). A life cycle assessment of clinker and cement production in Ethiopia. Cleaner Environmental Systems, 13, Article ID 100180.
Open this publication in new window or tab >>A life cycle assessment of clinker and cement production in Ethiopia
2024 (English)In: Cleaner Environmental Systems, E-ISSN 2666-7894, Vol. 13, article id 100180Article in journal (Refereed) Published
Abstract [en]

Cement production is a major consumer of energy and the largest source of industrial CO2 emissions. This study aims to perform an environmental life cycle assessment of clinker and cement production in Ethiopia, using ReCiPe impact assessment method. Inventory data (material, energy, and transportation) is collected from seven major Ethiopian cement industries. The midpoint analysis identified nine hotspot environmental concerns: global warming, ozone formation (human health and terrestrial ecosystem), particulate matter formation, terrestrial (acidification and ecotoxicity), freshwater eutrophication, human carcinogenic toxicity, and fossil resource scarcity. Human health emerged as the most significantly affected endpoint damage category by the midpoint impacts. Among the process stages included in clinker system boundary, clinker production phase (kiln emissions) is a significant contributor to the total score of the hotspot impacts, ranging from 60.7% to 91.8%. The clinker system is responsible for over 81.03% of the overall environmental burden of cement. The sensitivity analysis reveals that a 5% change in kiln energy consumption and transportation burden could lead to a reduction in hotspot impacts ranging from 1.8% to 5%. To foster reliability of this study, uncertainty analysis is also conducted. Overall, the findings indicate the need to enhance environmental sustainability in Ethiopian cement production.

Place, publisher, year, edition, pages
Elsevier BV, 2024
Keywords
Cement and clinker production, Cement industries, Environmental concerns, Ethiopia, Life cycle assessment
National Category
Environmental Management
Identifiers
urn:nbn:se:kth:diva-345235 (URN)10.1016/j.cesys.2024.100180 (DOI)001217787600001 ()2-s2.0-85189072661 (Scopus ID)
Note

QC 20240411

Available from: 2024-04-10 Created: 2024-04-10 Last updated: 2024-05-24Bibliographically approved
Bäcklund, K., Molinari, M., Lundqvist, P. & Palm, B. (2023). Building Occupants, Their Behavior and the Resulting Impact on Energy Use in Campus Buildings: A Literature Review with Focus on Smart Building Systems. Energies, 16(17), 6104-6104
Open this publication in new window or tab >>Building Occupants, Their Behavior and the Resulting Impact on Energy Use in Campus Buildings: A Literature Review with Focus on Smart Building Systems
2023 (English)In: Energies, E-ISSN 1996-1073, Vol. 16, no 17, p. 6104-6104Article in journal (Refereed) Published
Abstract [en]

In the light of global climate change and the current energy crisis, it is crucial to target sustainable energy use in all sectors. Buildings still remain one of the most energy-demanding sectors. Campus buildings and higher educational buildings are important to target due to their high and increasing energy demand. This building segment also represents a research gap, as mostly office or domestic buildings have been studied previously. In the quest for thermal comfort, a key stakeholder in building energy demand is the building occupant. It is therefore crucial to promote energy-aware behaviors. The building systems are another key factor to consider. As conventional building systems are replaced with smart building systems, the entire scenario is redrawn for how building occupants interact with the building and its systems. This study argues that behavior is evolving with the smartness of building systems. By means of a semi-systematic literature review, this study presents key findings from peer-reviewed research that deal with building occupant behavior, building systems and energy use in campus buildings. The literature review was an iterative process based on six predefined research questions. Two key results are presented: a graph of reported energy-saving potentials and a conceptual framework to evaluate building occupants impact on building energy use. Furthermore, based on the identified research gaps in the selected literature, areas for future research are proposed.

Place, publisher, year, edition, pages
MDPI AG, 2023
Keywords
behavior; energy use; campus buildings; building occupants; smart building systems; educational buildings
National Category
Building Technologies
Research subject
Energy Technology
Identifiers
urn:nbn:se:kth:diva-344411 (URN)10.3390/en16176104 (DOI)001070065200001 ()2-s2.0-85170534245 (Scopus ID)
Funder
Swedish Energy Agency, 2018-016237
Note

QC 20240315

Available from: 2024-03-15 Created: 2024-03-15 Last updated: 2024-03-15Bibliographically approved
Mazzotti, W., Lazzarotto, A., Acuña, J. & Palm, B. (2023). Calibration and Uncertainty Quantification for Single-Ended Raman-Based Distributed Temperature Sensing: Case Study in a 800 m Deep Coaxial Borehole Heat Exchanger. Sensors, 23(12), Article ID 5498.
Open this publication in new window or tab >>Calibration and Uncertainty Quantification for Single-Ended Raman-Based Distributed Temperature Sensing: Case Study in a 800 m Deep Coaxial Borehole Heat Exchanger
2023 (English)In: Sensors, E-ISSN 1424-8220, Vol. 23, no 12, article id 5498Article in journal (Refereed) Published
Abstract [en]

Raman-based distributed temperature sensing (DTS) is a valuable tool for field testing and validating heat transfer models in borehole heat exchanger (BHE) and ground source heat pump (GSHP) applications. However, temperature uncertainty is rarely reported in the literature. In this paper, a new calibration method was proposed for single-ended DTS configurations, along with a method to remove fictitious temperature drifts due to ambient air variations. The methods were implemented for a distributed thermal response test (DTRT) case study in an 800 m deep coaxial BHE. The results show that the calibration method and temperature drift correction are robust and give adequate results, with a temperature uncertainty increasing non-linearly from about 0.4 K near the surface to about 1.7 K at 800 m. The temperature uncertainty is dominated by the uncertainty in the calibrated parameters for depths larger than 200 m. The paper also offers insights into thermal features observed during the DTRT, including a heat flux inversion along the borehole depth and the slow temperature homogenization under circulation.

Place, publisher, year, edition, pages
MDPI AG, 2023
Keywords
distributed temperature sensing, DTS, uncertainty, fiber optic, Raman, borehole, temperature, deep coaxial BHE, DTRT, confidence intervals
National Category
Energy Engineering
Identifiers
urn:nbn:se:kth:diva-332185 (URN)10.3390/s23125498 (DOI)001015764800001 ()37420665 (PubMedID)2-s2.0-85164021704 (Scopus ID)
Note

QC 20230721

Available from: 2023-07-21 Created: 2023-07-21 Last updated: 2023-07-21Bibliographically approved
Shiravi, A. H., Ghanbarpour, M. & Palm, B. (2023). Experimental evaluation of the effect of mechanical subcooling on a hydrocarbon heat pump system. Energy, 274, Article ID 127406.
Open this publication in new window or tab >>Experimental evaluation of the effect of mechanical subcooling on a hydrocarbon heat pump system
2023 (English)In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 274, article id 127406Article in journal (Refereed) Published
Abstract [en]

In addition to the progressive movement of countries towards the use of renewable energy sources, efficient energy consumption is another important goal set by the International Energy Agency. In heat pump technology, the use of mechanical subcooling system has a high potential for this purpose. In this experimental study, the impact of using a mechanical subcooling cycle on the performance of a heat pump system is investigated. The system is designed to supply heat at condensing temperatures of 50, 60 and 70 degrees C. Propane and isobutane are used as low GWP refrigerants in the main and secondary cycles, respectively. The results revealed that both the COP and heating capacity of the system are increased by adding the mechanical subcooling cycle up to 15.1% and 34%, respectively. To express the improvement of the system performance by means of the TEWI index, a reduction of 9-13% is calculated when the mechanical subcooling cycle is included. It is also of interest that the cooling coefficient of performance (COP2) is improved by adjoining a secondary cycle as a liquid subcooler. An optimal power ratio between the basic cycle and the secondary cycle was obtained, which is consistent with the simulation results.

Place, publisher, year, edition, pages
Elsevier BV, 2023
Keywords
heat Pump, mechanical subcooling, Hydrocarbons, Heating capacity, COP, TEWI
National Category
Energy Engineering
Identifiers
urn:nbn:se:kth:diva-327436 (URN)10.1016/j.energy.2023.127406 (DOI)000976830500001 ()2-s2.0-85152661293 (Scopus ID)
Note

QC 20230529

Available from: 2023-05-29 Created: 2023-05-29 Last updated: 2023-05-29Bibliographically approved
Ignatowicz, M. & Palm, B. (2023). Experimental investigation of thermophysical properties of ethylene glycol based secondary fluids. International journal of refrigeration, 155, 137-153
Open this publication in new window or tab >>Experimental investigation of thermophysical properties of ethylene glycol based secondary fluids
2023 (English)In: International journal of refrigeration, ISSN 0140-7007, E-ISSN 1879-2081, Vol. 155, p. 137-153Article in journal (Refereed) Published
Abstract [en]

Aqueous solutions of ethylene glycol are commonly used as secondary fluids in different indirect refrigeration systems and heat pumps as well as nanofluids. A very extensive literature review has been done, including more than 90 references published from 1905 to 2023. Despite the wide application and importance, especially in the energy sector, ethylene glycol solutions seem to be less investigated in low temperature ranges and more research is required to improve the quality and quantity of available data. The novelty of this paper is to investigate the most important thermophysical properties of ethylene glycol solutions in low temperatures. In this study a different approach was made and solutions having a specific freezing point temperature (between -5 and -50 ºC) rather than specific concentration were investigates in temperature ranges applicable for different cooling applications. The concentrations giving a certain freezing point temperature seemed to deviate in some cases with 1–2 wt-% between different sources. Nevertheless, the density results were in rather good agreement with all reference data. The viscosity results were lower by up to ±10% compared to reference values. Additionally, the obtained experimental results for thermal conductivity were higher by up to 12% compared to ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers) data. The specific heat capacity results were higher by up to 14.6% and 5.4% than current reference data. There is a high probability that the current ASHRAE data for specific heat are actually indirectly calculated values from thermal conductivity data and not validated using differential scanning calorimetry techniques.

Place, publisher, year, edition, pages
Elsevier BV, 2023
Keywords
Ethylene glycol, indirect Refrigeration system, Secondary fluid, Thermophysical properties
National Category
Energy Engineering
Identifiers
urn:nbn:se:kth:diva-338342 (URN)10.1016/j.ijrefrig.2023.08.008 (DOI)001098982100001 ()2-s2.0-85173242222 (Scopus ID)
Note

QC 20231020

Available from: 2023-10-20 Created: 2023-10-20 Last updated: 2023-11-30Bibliographically approved
Mossie, A. T., Khatiwada, D., Palm, B. & Bekele, G. (2023). Investigating energy saving and climate mitigation potentials in cement production: A case study in Ethiopia. Energy Conversion and Management, 287, 117111, Article ID 117111.
Open this publication in new window or tab >>Investigating energy saving and climate mitigation potentials in cement production: A case study in Ethiopia
2023 (English)In: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 287, p. 117111-, article id 117111Article in journal (Refereed) Published
Abstract [en]

The cement industry is one of the most energy and emission-intensive sectors, accounting for approximately 7% of total-industrial energy use and 7% of global CO2 emissions. This study investigates the potential energy savings and CO2 abatement in the cement plants of Ethiopia. A Benchmarking and Energy Saving Tool for Cement is used to compare the energy use performance of the individual cement plants to best practices. The study reveals that all the surveyed plants are less efficient, with an average energy saving potential of 36% indicating a significant potential for energy efficiency improvement. Then, twenty-eight energy efficiency measures are identified and analyzed using a bottom-up energy conservation supply curve model. The results show that the cost-effective electrical energy and fuel-saving potentials of these measures are estimated to be 99 Gigawatt hours per year which is about 11.5% of the plants' annual electrical energy consumption and, 2.7 Petajoules per year which is to be 12.5% of the plants' annual fuel consumption, respectively. The cost-effective fuel measures have an annual average CO2 emission reduction potential of 254 kilo-tonnes per year which covers about 5% of the total CO2 emission. Sensitivity analysis is conducted using the key parameters that show some discrepancy in the base case results. This study could be used as a reference for policymakers to understand the potential for energy savings and CO2 abatement. It could also be used to design policies in improving energy efficiency in the cement sector.

Place, publisher, year, edition, pages
Elsevier BV, 2023
Keywords
Energy intensity, Energy efficiency measures, Cost of conserved energy, Energy conservation supply curve, Climate change mitigation, Cement industry
National Category
Energy Engineering
Identifiers
urn:nbn:se:kth:diva-329944 (URN)10.1016/j.enconman.2023.117111 (DOI)001004189500001 ()2-s2.0-85156170754 (Scopus ID)
Note

QC 20230626

Available from: 2023-06-26 Created: 2023-06-26 Last updated: 2023-06-26Bibliographically approved
Mejia-Solis, E., Arias Hurtado, J. & Palm, B. (2023). Simple solutions for improving thermal comfort in huts in the highlands of Peru. Heliyon, 9(10), Article ID e19709.
Open this publication in new window or tab >>Simple solutions for improving thermal comfort in huts in the highlands of Peru
2023 (English)In: Heliyon, E-ISSN 2405-8440, Vol. 9, no 10, article id e19709Article in journal (Refereed) Published
Abstract [en]

In the Peruvian mountains, hundreds of thousands of rural households living in poverty live in cold indoor environments, close to 0 °C. Indoor cold causes thousands of respiratory diseases and excess of winter deaths. In this study, we numerically calculated the impact of simple low-cost refurbishments on discomfort time during a year. Using EnergyPlus and Python, we modelled a typical one-room hut used as bedroom built with a metal-sheet roof, adobe walls, dirt floors, and high infiltration rates. Then, 9 individual solutions were studied, and their combination resulted in 215 different hut designs. The model was calibrated with field measurements to estimate the infiltration. All the numerical calculations included an uncertainty analysis based on Monte Carlo method, and a sensitivity analysis to assess the impact of reducing infiltration on discomfort time. The base case had a discomfort time of 44% of time. The calibration of infiltration resulted in a mean hourly air exchange rate equal to 29.1 h−1 (SD = 17.0 h−1). Five different designs formed the Pareto front that optimized discomfort time and costs. The solution with the lowest discomfort time during a year, 37% of the time, was adding insulation to the roof (U = 0.83 W/m2•K) and the door (U = 1.00 W/m2•K); and its cost was 286USD. In this solution, when infiltrations were reduced to 4.1 h−1 (SD = 4.1 h−1) discomfort time decreased until 16%. These results benefit those households that nowadays invest their limited resources to improve their living conditions but without technical guidance.

Place, publisher, year, edition, pages
Elsevier BV, 2023
Keywords
Andes, Building performance simulation, Low indoor temperatures, Low-cost refurbishments, Uncertainty analysis
National Category
Building Technologies
Identifiers
urn:nbn:se:kth:diva-337426 (URN)10.1016/j.heliyon.2023.e19709 (DOI)001156762900001 ()2-s2.0-85171746122 (Scopus ID)
Note

QC 20231003

Available from: 2023-10-03 Created: 2023-10-03 Last updated: 2024-02-26Bibliographically approved
Mossie, A. T., Wolde, M. G., Beyene, G. B., Palm, B. & Khatiwada, D. (2021). A comparative study of the energy and environmental performance of cement industries in Ethiopia and Sweden. In: International Conference on Electrical, Computer, Communications and Mechatronics Engineering, ICECCME 2021: . Paper presented at 2021 IEEE International Conference on Electrical, Computer, Communications and Mechatronics Engineering, ICECCME 2021, 7-8 October 2021, Mauritius.. Institute of Electrical and Electronics Engineers (IEEE)
Open this publication in new window or tab >>A comparative study of the energy and environmental performance of cement industries in Ethiopia and Sweden
Show others...
2021 (English)In: International Conference on Electrical, Computer, Communications and Mechatronics Engineering, ICECCME 2021, Institute of Electrical and Electronics Engineers (IEEE) , 2021Conference paper, Published paper (Refereed)
Abstract [en]

Cement industry is both energy and emission intensive. This paper examines energy and environmental performance of cement plants in Ethiopia and Sweden. Energy intensity (thermal and electrical), alternative fuel (AF) share, CO2 emission intensity and clinker substitute rate are applied to compare Ethiopia and Sweden cement industries. In most of the parameters, the Ethiopian cement industry ranks lower than the Sweden cement industry. The average thermal and electrical energy intensities for the Ethiopian cement industry is 3.76 gigajoules per tonne of clinker (GJ/t clinker) and 138.6 kilowatt hours per tonne of cement (KWh/t cement), respectively. Whereas, in Sweden cement industry, the average intensity is about 3.6 GJ/t clinker for thermal and 131 KWh/t cement for electricity. The emission intensity is 0.853 tonne CO2/tonne clinker (0.853t CO2/t clinker) in Ethiopia and 0.701t CO2/t clinker in Sweden. The alternative fuel (AF) share reaches 62% in Sweden cement industry, while in Ethiopia the share is almost insignificant (less than 1%). Adoption of specific energy efficiency measures, such as waste heat recovery power plant (WHRPP) and thermal fuel switch, significantly improved both the energy and environmental performances of Sweden cement industry. Therefore, this study suggests deployment of WHRPP and raise of AF share in Ethiopian cement industry, but the technical and economic viability of these measures should be investigated in the context of Ethiopian cement plants.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2021
Keywords
Alternative fuel, CO2emission intensity, Energy efficiency measures, Energy intensity, Alternative fuels, Carbon dioxide, Cements, Environmental management, Waste heat, Waste heat utilization, CO 2 emission, Efficiency measure, Emissions intensity, Energy efficiency measure, Energy performance, Environmental performance, Ethiopia, Thermal, Energy efficiency
National Category
Other Civil Engineering
Identifiers
urn:nbn:se:kth:diva-313268 (URN)10.1109/ICECCME52200.2021.9591148 (DOI)2-s2.0-85119430037 (Scopus ID)
Conference
2021 IEEE International Conference on Electrical, Computer, Communications and Mechatronics Engineering, ICECCME 2021, 7-8 October 2021, Mauritius.
Note

Part of proceedings: ISBN 978-1-6654-1262-9

QC 20220608

Available from: 2022-06-08 Created: 2022-06-08 Last updated: 2023-01-17Bibliographically approved
Criscuolo, G., Markussen, W. B., Meyer, K. E., Palm, B. & Kaern, M. R. (2021). Experimental Characterization of the Heat Transfer in Multi-Microchannel Heat Sinks for Two-Phase Cooling of Power Electronics. Fluids, 6(2), Article ID 55.
Open this publication in new window or tab >>Experimental Characterization of the Heat Transfer in Multi-Microchannel Heat Sinks for Two-Phase Cooling of Power Electronics
Show others...
2021 (English)In: Fluids, E-ISSN 2311-5521, Vol. 6, no 2, article id 55Article in journal (Refereed) Published
Abstract [en]

This study aims to characterize experimentally the heat transfer in micro-milled multi-microchannels copper heat sinks operating with flow boiling, in the attempt to contribute to the development of novel and high heat flux thermal management systems for power electronics. The working fluid was R-134a and the investigation was conducted for a nominal outlet saturation temperature of 30 degrees C. The microchannels were 1 cm long and covered a square footprint area of 1 cm(2). Boiling curves starting at low vapor quality and average heat transfer coefficients were obtained for nominal channel mass fluxes from 250 kg/m(2)s to 1100 kg/m(2)s. The measurements were conducted by gradually increasing the power dissipation over a serpentine heater soldered at the bottom of the multi-microchannels, until a maximum heater temperature of 150 degrees C was reached. Infrared thermography was used for the heater temperature measurements, while high-speed imaging through a transparent top cover provided visual access over the entire length of the channels. The average heat transfer coefficient increased with the dissipated heat flux until a decrease dependent on hydrodynamic effects occurred, possibly due to incomplete wall wetting. Depending on the channel geometry, a peak value of 200 kW/m(2)K for the footprint heat transfer coefficient and a maximum dissipation of 620 W/cm(2) at the footprint with a limit temperature of 150 degrees C could be obtained, showing the suitability of the investigated geometries in high heat flux cooling of power electronics. The experimental dataset was used to assess the prediction capability of selected literature correlations. The prediction method by Bertsch et al. gave the best agreement with a mean absolute percent error of 24.5%, resulting to be a good design tool for flow boiling in high aspect ratio multi-microchannels as considered in this study.

Place, publisher, year, edition, pages
MDPI, 2021
Keywords
flow boiling, microchannel, power electronics, thermal management, pumped two-phase
National Category
Energy Engineering
Identifiers
urn:nbn:se:kth:diva-292268 (URN)10.3390/fluids6020055 (DOI)000622534200001 ()2-s2.0-85107983102 (Scopus ID)
Note

QC 20210401

Available from: 2021-04-01 Created: 2021-04-01 Last updated: 2022-06-25Bibliographically approved
Su, C., Dalgren, J. & Palm, B. (2021). High-resolution mapping of the clean heat sources for district heating in Stockholm City. Energy Conversion and Management, 235, Article ID 113983.
Open this publication in new window or tab >>High-resolution mapping of the clean heat sources for district heating in Stockholm City
2021 (English)In: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 235, article id 113983Article in journal (Refereed) Published
Abstract [en]

Decarbonizing the district heating sector is a key measure to achieve the 2040 net-zero emissions target for Stockholm City. One significant question to answer is to find out the locations of all the clean non-fossil fuel heat sources that could be used for district heating within the city?s administrative boundary, and to evaluate how much heat could be extracted from these heat sources. This paper maps out both the geolocations and the technical potentials of the clean non-fossil fuel heat sources for densely populated Stockholm City region, using Geographical Information System based integrative-analysis method. The mapping achieves 1-meter highresolution and provides integrated open datasets to overcome the data availability issue. The mapping results show that a great number of clean and non-fossil fuel heat sources are available for district heating in Stockholm City. By fully unlocking the potentials of these heat sources, around 7054 GWh heat energy is estimated to be possibly exploited per year, which could cover 100% of the existing district heating energy requirement in Stockholm City. The potential share of each mapped heat source is: water bodies 48.3%, data centers 45.4%, supermarkets 4.5%, underground subway stations 0.8%, sewage plants 0.5%, shallow geothermal 0.3% and ice rinks 0.2%. A total of 9 heat sources clusters are identified, which could be prioritized for clean heating energy exploitation. By using the high-resolution mapping, the district heating utilities could plan the capacity in a forward looking way according to the local heat source availability. The method pipeline developed in this study could be recommended to other cities with district heating needs and assist their clean district heating transition roadmap design.

Place, publisher, year, edition, pages
Elsevier BV, 2021
Keywords
District heating, Heat source, Geographical Information System (GIS), High-resolution
National Category
Energy Systems
Identifiers
urn:nbn:se:kth:diva-293554 (URN)10.1016/j.enconman.2021.113983 (DOI)000636289300002 ()2-s2.0-85102389567 (Scopus ID)
Note

QC 20210517

Available from: 2021-05-17 Created: 2021-05-17 Last updated: 2022-06-25Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-9902-2087

Search in DiVA

Show all publications