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Karimipanah, Taghi, ProfessorORCID iD iconorcid.org/0000-0002-9392-424x
Publications (10 of 35) Show all publications
Ameen, A., Cehlin, M., Yamasawa, H., Kobayashi, T. & Karimipanah, T. (2023). Energy saving, indoor thermal comfort and indoor air quality evaluation of an office environment using corner impinging jet ventilation. Developments in the Built Environment, 15, Article ID 100179.
Open this publication in new window or tab >>Energy saving, indoor thermal comfort and indoor air quality evaluation of an office environment using corner impinging jet ventilation
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2023 (English)In: Developments in the Built Environment, ISSN 2666-1659, Vol. 15, article id 100179Article in journal (Refereed) Published
Abstract [en]

The performance of a corner based impinging jet ventilation system (CIJV) in an office environment was evaluated numerically. The evaluation was done both in terms of the local thermal comfort and the local indoor air quality. Three different inlet configurations were tested for a range of outdoor temperatures that included both winter and summer conditions. In terms of indoor air quality, the results showed that CIJV performed better than a traditional mixing system. The study also revealed that CIJV creates a stronger temperature stratification in summertime compared to wintertime. When evaluating the energy saving potential the results showed a possible reduction of 7% for the ventilation flowrate when the outdoor temperatures were between -15 °C and -5 °C, 8 % when the outdoor temperatures were between 0 °C and 10 °C and 9 % when the outdoor temperatures were between 15 °C and 25 °C.

Place, publisher, year, edition, pages
Elsevier, 2023
Keywords
Corner impinging jet ventilation, Computational fluid dynamic, Thermal comfort, Indoor air quality, Energy saving
National Category
Energy Systems
Research subject
Sustainable Urban Development
Identifiers
urn:nbn:se:hig:diva-41938 (URN)10.1016/j.dibe.2023.100179 (DOI)001054802900001 ()2-s2.0-85161659218 (Scopus ID)
Available from: 2023-06-02 Created: 2023-06-02 Last updated: 2023-09-07Bibliographically approved
Ameen, A., Cehlin, M. & Karimipanah, T. (2023). Numerical investigation of indoor thermal comfort and air quality for an office equipped with corner impinging jet ventilation. Advances in Building Energy Research, 17(5), 578-604
Open this publication in new window or tab >>Numerical investigation of indoor thermal comfort and air quality for an office equipped with corner impinging jet ventilation
2023 (English)In: Advances in Building Energy Research, ISSN 1751-2549, E-ISSN 1756-2201, Vol. 17, no 5, p. 578-604Article in journal (Refereed) Published
Abstract [en]

This study investigates the feasibility of using only corner impinging jet ventilation (CIJV) for heating and cooling a medium-sized office space with two occupants while maintaining adequate indoor thermal comfort and air quality compared to traditional mixing ventilation systems. This study examines what impact various outdoor temperatures, ranging from −15°C to 25°C, have on an office environment in terms of indoor thermal comfort and air quality. Three different workspace positions were evaluated. The results show that the CIJV system meets the ASHRAE thermal comfort standards for all three positions. In terms of indoor air quality, CIJV performs better than traditional mixing systems, with improved mean age of air and ACE values. This study concludes that CIJV can be used both close and far away from the supply inlets and still provide adequate indoor thermal comfort and air quality during both cooling and heating season.

Place, publisher, year, edition, pages
Taylor & Francis, 2023
Keywords
corner impinging jet ventilation, heating and cooling, computational fluid dynamic, thermal comfort, indoor air quality
National Category
Energy Systems
Research subject
Sustainable Urban Development
Identifiers
urn:nbn:se:hig:diva-43137 (URN)10.1080/17512549.2023.2269925 (DOI)001088045800001 ()2-s2.0-85174303303 (Scopus ID)
Available from: 2023-10-17 Created: 2023-10-17 Last updated: 2023-12-05Bibliographically approved
Karimipanah, T. (2021). Some Aspects of HVAC Design in Energy Renovation of Buildings. In: Marita Wallhagen & Mathias Cehlin (Ed.), Urban Transition - Perspectives on Urban Systems and Environments: . IntechOpen
Open this publication in new window or tab >>Some Aspects of HVAC Design in Energy Renovation of Buildings
2021 (English)In: Urban Transition - Perspectives on Urban Systems and Environments / [ed] Marita Wallhagen & Mathias Cehlin, IntechOpen , 2021Chapter in book (Refereed)
Abstract [en]

It is well-known fact that air conditioning systems are responsible for a significant part of all energy systems in building energy usage. In EU buildings, the building HVAC systems account for ca 50% of the energy consumed. In the U.S., air-conditioning accounts on average about 12% of residential energy expenditures. The proper choice of air distribution systems and sustainable energy sources to drive the electrical components have a vital impact to achieve the best requirements for indoor climate including, hygienical, thermal, and reasonable energy-saving goals. The building energy system components that have a considerable impact on the demand for final energy in the building are design, outdoor environment conditions, HVAC systems, water consumption, electrical appliances, indoor thermal comfort, and indoor human activities. For calculation of the energy balance in a building, we need to consider the total energy flows in and out from the building including ventilation heat losses, the perimeters transmission heat loses, solar radiation, internal heat from occupants and appliances, space and domestic water heating, air leakage, and sewage heat losses. However, it is a difficult task to handle the above time-dependent parameters therefore an energy simulation program will always be used. This chapter aims to assess the role of ventilation and airconditioning of buildings through the sustainability approaches and some of the existing renewable energy-based methods of HVAC systems are presented. This comprehensive review has been shown that using the new air distribution systems in combination with renewable energy sources are key factors to improve the HVAC performance and move toward Nearly Zero Carbon Buildings (NZCB).

Place, publisher, year, edition, pages
IntechOpen, 2021
Keywords
Sustainable HVAC systems, building energy systems, thermal comfort, indoor human activities, Energy balance, Energy saving potential, Nearly Zero Carbon Buildings (NZCB)
National Category
Energy Engineering
Research subject
Sustainable Urban Development
Identifiers
urn:nbn:se:hig:diva-37179 (URN)10.5772/intechopen.98824 (DOI)
Note

kommande

Available from: 2021-10-18 Created: 2021-10-18 Last updated: 2021-10-20Bibliographically approved
Yang, B., Melikov, A., Kabanshi, A., Zhang, C., Bauman, F. S., Cao, G., . . . Lin, Z. (2019). A review of advanced air distribution methods - theory, practice, limitations and solutions. Energy and Buildings, 202, Article ID 109359.
Open this publication in new window or tab >>A review of advanced air distribution methods - theory, practice, limitations and solutions
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2019 (English)In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 202, article id 109359Article in journal (Refereed) Published
Abstract [en]

Ventilation and air distribution methods are important for indoor thermal environments and air quality. Effective distribution of airflow for indoor built environments with the aim of simultaneously offsetting thermal and ventilation loads in an energy efficient manner has been the research focus in the past several decades. Based on airflow characteristics, ventilation methods can be categorized as fully mixed or non-uniform. Non-uniform methods can be further divided into piston, stratified and task zone ventilation. In this paper, the theory, performance, practical applications, limitations and solutions pertaining to ventilation and air distribution methods are critically reviewed. Since many ventilation methods are buoyancy driving that confines their use for heating mode, some methods suitable for heating are discussed. Furthermore, measuring and evaluating methods for ventilation and air distribution are also discussed to give a comprehensive framework of the review.

Keywords
Fully mixing ventilation, Non-uniform ventilation, Air distribution, Thermal comfort, Air quality, Energy efficiency
National Category
Other Engineering and Technologies
Research subject
Sustainable Urban Development
Identifiers
urn:nbn:se:hig:diva-30538 (URN)10.1016/j.enbuild.2019.109359 (DOI)000503829200053 ()2-s2.0-85070316248 (Scopus ID)
Available from: 2019-08-22 Created: 2019-08-22 Last updated: 2021-03-31Bibliographically approved
Cehlin, M., Karimipanah, T., Larsson, U. & Ameen, A. (2019). Comparing thermal comfort and air quality performance of two active chilled beam systems in an open-plan office. Journal of Building Engineering, 22, 56-65
Open this publication in new window or tab >>Comparing thermal comfort and air quality performance of two active chilled beam systems in an open-plan office
2019 (English)In: Journal of Building Engineering, E-ISSN 2352-7102, Vol. 22, p. 56-65Article in journal (Refereed) Published
Abstract [en]

The traditional air distribution and supply devices in ventilated rooms are not always able to effectively remove excess heat from the space. Therefore, chilled beams, especially the active systems, are used to achieve the desired cooling demand. The focus of this paper was the potential benefit of a newly designed active chilled beam (ACB) system, to improve heat removal effectiveness local thermal condition and indoor air quality in the occupants’ breathing zone. The system based on 1-way flow design (1W-ACB) was installed in an open-plan office and its performance was studied by analysing the temperatures, velocities and tracer gas concentrations in predetermined risky zones. The system was compared against a traditional 4-way flow design (4W-ACB).

The obtained results showed that heat removal effectiveness was slightly higher for the 1W-ACB system compared to the 4W-ACB system. The local thermal condition was very good close to the workstations when using 1W-ACB. The benefits of the new system were also shown in the occupied zone by analysing the mean age of air and air-change effectiveness (ACE) in the breathing level at the workstation locations. The 1W-ACB system provided air with lower mean age (fresher air), and therefore higher ACE, near the breathing zone at the workstations compared to the 4W-ACB. On the other hand, the 4W-ACB system had the advantage of providing high thermal and mean age of air uniformity throughout the room.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Active Chilled Beam, Air Change Effectiveness, Heat Removal Effectiveness
National Category
Energy Engineering
Research subject
Sustainable Urban Development
Identifiers
urn:nbn:se:hig:diva-28583 (URN)10.1016/j.jobe.2018.11.013 (DOI)000457639900006 ()2-s2.0-85057839765 (Scopus ID)
Funder
Vinnova, 2013-03772
Available from: 2018-11-22 Created: 2018-11-22 Last updated: 2021-03-31Bibliographically approved
Ameen, A., Cehlin, M., Larsson, U. & Karimipanah, T. (2019). Experimental Investigation of Ventilation Performance of Different Air Distribution Systems in an Office Environment: Heating Mode. Energies, 12(10), Article ID 1835.
Open this publication in new window or tab >>Experimental Investigation of Ventilation Performance of Different Air Distribution Systems in an Office Environment: Heating Mode
2019 (English)In: Energies, E-ISSN 1996-1073, Vol. 12, no 10, article id 1835Article in journal (Refereed) Published
Abstract [en]

A vital requirement for all-air ventilation systems are their functionality to operate both in cooling and heating mode. This article experimentally investigates two newly designed air distribution systems, corner impinging jet (CIJV) and hybrid displacement ventilation (HDV) in comparison against a mixing type air distribution system. These three different systems are examined and compared to one another to evaluate their performance based on local thermal comfort and ventilation effectiveness when operating in heating mode. The evaluated test room is an office environment with two workstations. One of the office walls, which has three windows, faces a cold climate chamber. The results show that CIJV and HDV perform similar to a mixing ventilation in terms of ventilation effectiveness close to the workstations. As for local thermal comfort evaluation, the results show a small advantage for CIJV in the occupied zone. Comparing C2-CIJV to C2-CMV the average draught rate (DR) in the occupied zone is 0.3% for C2-CIJV and 5.3% for C2-CMV with the highest difference reaching as high as 10% at the height of 1.7 m. The results indicate that these systems can perform as well as mixing ventilation when used in offices that require moderate heating. The results also show that downdraught from the windows greatly impacts on the overall airflow and temperature pattern in the room.

Keywords
Corner impinging jet, mixing ventilation, displacement ventilation, tracer gas, air exchange effectiveness, air change effectiveness, draught rate
National Category
Energy Systems
Research subject
Sustainable Urban Development
Identifiers
urn:nbn:se:hig:diva-29582 (URN)10.3390/en12101835 (DOI)000471016700014 ()2-s2.0-85066877057 (Scopus ID)
Note

Funding agency:

- University of Gävle

Available from: 2019-05-21 Created: 2019-05-21 Last updated: 2023-08-28Bibliographically approved
Ameen, A., Cehlin, M., Larsson, U. & Karimipanah, T. (2019). Experimental investigation of ventilation performance of different air distribution systems in an office environment – cooling mode. Energies, 12(7), Article ID 1354.
Open this publication in new window or tab >>Experimental investigation of ventilation performance of different air distribution systems in an office environment – cooling mode
2019 (English)In: Energies, E-ISSN 1996-1073, Vol. 12, no 7, article id 1354Article in journal (Refereed) Published
Abstract [en]

The performance of a newly designed corner impinging jet air distribution method with an equilateral triangle cross section was evaluated experimentally and compared to that of two more traditional methods (mixing and displacement ventilation). At nine evenly chosen positions with four standard vertical points, air velocity, turbulence intensity, temperature, and tracer gas decay measurements were conducted for all systems. The results show that the new method behaves as a displacement ventilation system, with high air change effectiveness and stratified flow pattern and temperature field. Both local air change effectiveness and air exchange effectiveness of the corner impinging jet showed high quality and promising results, which is a good indicator of ventilation effectiveness. The results also indicate that there is a possibility to slightly lower the airflow rates for the new air distribution system, while still meeting the requirements for thermal comfort and indoor air quality, thereby reducing fan energy usage. The draught rate was also lower for corner impinging jet compared to the other tested air distribution methods. The findings of this research show that the corner impinging jet method can be used for office ventilation.

Place, publisher, year, edition, pages
MDPI, 2019
Keywords
Corner impinging jet, mixing ventilation, displacement ventilation, tracer gas, air exchange effectiveness, air change effectiveness, draught rate
National Category
Energy Engineering
Research subject
Sustainable Urban Development
Identifiers
urn:nbn:se:hig:diva-29443 (URN)10.3390/en12071354 (DOI)000465561400171 ()2-s2.0-85065464428 (Scopus ID)
Available from: 2019-04-05 Created: 2019-04-05 Last updated: 2023-08-28Bibliographically approved
Vachaparambil, K. J., Cehlin, M. & Karimipanah, T. (2018). Comparative Numerical Study of the Indoor Climate for Mixing and Confluent Jet Ventilation Systems in an Open-plan Office. In: Proceedings of the 4th international Conference on Building Energy & Environment: . Paper presented at COBEE2018, 4th international Conference on Building Energy & Environment, 5-9 February 2018, Melbourne, Australia (pp. 73-78). Melbourne: Conference On Building Energy & Environment - COBEE2018, Melbourne Australia
Open this publication in new window or tab >>Comparative Numerical Study of the Indoor Climate for Mixing and Confluent Jet Ventilation Systems in an Open-plan Office
2018 (English)In: Proceedings of the 4th international Conference on Building Energy & Environment, Melbourne: Conference On Building Energy & Environment - COBEE2018, Melbourne Australia , 2018, p. 73-78Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
Melbourne: Conference On Building Energy & Environment - COBEE2018, Melbourne Australia, 2018
Keywords
Confluent jet ventilation
National Category
Energy Engineering
Research subject
Sustainable Urban Development
Identifiers
urn:nbn:se:hig:diva-26568 (URN)978-0-646-98213-7 (ISBN)
Conference
COBEE2018, 4th international Conference on Building Energy & Environment, 5-9 February 2018, Melbourne, Australia
Available from: 2018-05-15 Created: 2018-05-15 Last updated: 2021-02-17Bibliographically approved
Sadrizadeh, S., Afshari, A., Karimipanah, T., Håkansson, U. & Nielsen, P. (2016). Numerical simulation of the impact of surgeon posture on airborne particle distribution in a turbulent mixing operating theatre. Building and Environment, 110, 140-147
Open this publication in new window or tab >>Numerical simulation of the impact of surgeon posture on airborne particle distribution in a turbulent mixing operating theatre
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2016 (English)In: Building and Environment, ISSN 0360-1323, E-ISSN 1873-684X, Vol. 110, p. 140-147Article in journal (Refereed) Published
Abstract [en]

Airborne particles released from surgical team members are major sources of surgical site infections. To reduce the risk of such infections, ultraclean-zoned ventilation systems have been widely applied, as a complement to the ventilation of the main operating theatre. The function of ventilation in an operating theatre is usually determined without considering the influence of the staff members’ posture and movements. The question of whether the surgeon's posture during an on-going operation will influence particle distribution within the surgical area has not yet been explored in depth or well documented. In the present study we analysed data from investigation of two positions (bending and straightened up), which represent the most common surgeon and staff-member postures. The investigation was performed by applying the computational fluid dynamics methodology to solve the governing equations for airflow and airborne particle dispersion. Ultraclean-zoned ventilation systems were examined as an addition to the conventional operating theatre. We examined three distinct source strengths (mean value of pathogens emitted from one person per second) due to the variety of staff clothing systems. In the upright posture, the screen units reduced the mean air counts of bacteria and the mean counts of sedimenting bacteria to a standard level for infection-prone surgeries in the surgical area. However, the performance of this system could be reduced drastically by improper work experience. Surgical garments with a high protective capacity result in lower source strength and thus reduces the particle concentration within the surgical area. These results are useful for developing best practices to prevent or at least reduce the infection rate during a surgical intervention.

Keywords
Bacteria-carrying particles; CFD simulation; Clothing system; Colony-forming unit; Mobile ultraclean zonal-laminar airflow screen; Operating theatre; Ventilation system
National Category
Mechanical Engineering Medical Engineering
Identifiers
urn:nbn:se:hig:diva-22648 (URN)10.1016/j.buildenv.2016.10.005 (DOI)000388052500013 ()2-s2.0-84992209616 (Scopus ID)
Funder
Swedish Research Council Formas, 2014-1492-28222-29
Available from: 2016-10-22 Created: 2016-10-22 Last updated: 2018-03-22Bibliographically approved
Arghand, T., Karimipanah, T., Awbi, H., Cehlin, M., Larsson, U. & Linden, E. (2015). An experimental investigation of the flow and comfort parameters for under-floor, confluent jets and mixing ventilation systems in an open-plan office. Building and Environment, 92, 48-60
Open this publication in new window or tab >>An experimental investigation of the flow and comfort parameters for under-floor, confluent jets and mixing ventilation systems in an open-plan office
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2015 (English)In: Building and Environment, ISSN 0360-1323, E-ISSN 1873-684X, Vol. 92, p. 48-60Article in journal (Refereed) Published
Abstract [en]

There is a new trend to convert the workplaces from individual office rooms to open offices for motivating money saving and better communication. With such a shift the ability of existing ventilation systems in meeting the new requirements is a challenging question for researchers. The available options could have an impact on workers' health in terms of providing acceptable levels of thermalcomfort and indoor air quality. Thus, this experimental investigation focuses on the performances of three different air distribution systems in an open-plan office space. The investigated systems were: mixing ventilation with ceiling-mounted inlets, confluent jets ventilation and underfloor air distribution with straight and curved vanes. Although this represents a small part of our more extensiveexperimental investigation, the results show that all the purposed stratified ventilation systems (CJV and UFAD) were more or less behaving as mixing systems with some tendency for displacement effects. Nevertheless, it is known that the mixing systems have a stable flow pattern but has the disadvantage of mixing contaminated air with the fresh supplied air which may produce lower performance and in worst cases occupants' illness. For the open-plan office we studied here, it will be shown that the new systems are capable of performing better than the conventional mixing systems. As expected, the higher air exchange efficiency in combination with lower local mean age of air for corner-mounted CJV and floor-mounted UFAD grills systems indicates that these systems are suitable for open-plan offices and are to be favored over conventional mixing systems.

Keywords
Open office, Mixing ventilation (MV), Underfloor air distribution (UFAD), Confluent jets ventilation (CJV)
National Category
Building Technologies
Identifiers
urn:nbn:se:hig:diva-19327 (URN)10.1016/j.buildenv.2015.04.019 (DOI)000358807800006 ()2-s2.0-84929492281 (Scopus ID)
Funder
VINNOVA
Available from: 2015-05-16 Created: 2015-05-16 Last updated: 2022-09-19Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-9392-424x

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