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Ploskic, A., Wang, Q. & Sadrizadeh, S. (2019). A holistic performance evaluation of ventilation radiators – An assessment according to EN 442-2 using numerical simulations. Journal of Building Engineering, 25, Article ID 100818.
Open this publication in new window or tab >>A holistic performance evaluation of ventilation radiators – An assessment according to EN 442-2 using numerical simulations
2019 (English)In: Journal of Building Engineering, E-ISSN 2352-7102, Vol. 25, article id 100818Article in journal (Refereed) Published
Abstract [en]

This research explored the importance of airflow rate and convector plate design on the operational performance of heating radiators equipped with an air device (ventilation radiators). The radiator was analyzed according to European Norm EN 442-2 using numerical simulations. The largest benefit of using staggered convector plates was the more efficient preheating of the incoming outdoor air supply. With this plate design, the evaluated radiator increased the temperature of the incoming airflow of 10 l/s from -5 °C to 26 °C with water supply/return temperatures of 45 °C/35 °C. With these water temperatures, the radiator was able to cover a room heat loss of 34 W/m2 floor area. However, the design of the convector plate alone was found to have a limited impact on the heat output from the radiator. Neither did the plate design significantly affect the uniformity of heat distribution nor the vertical temperature stratification inside the room. The results also showed that ventilation radiators might cover a building heating load (kW) with a lower supply water temperature but not necessarily give a lower annual energy use (kWh) for the space heating of a building.

Place, publisher, year, edition, pages
I: Elsevier, 2019
Keywords
Radiator, Low-temperature heating, Ventilation, Heat transfer, Staggered channels, Energy
National Category
Energy Engineering
Research subject
Energy Technology; Energy Technology; Civil and Architectural Engineering
Identifiers
urn:nbn:se:kth:diva-258927 (URN)10.1016/j.jobe.2019.100818 (DOI)000477702200050 ()2-s2.0-85067571725 (Scopus ID)
Funder
Svenska Byggbranschens Utvecklingsfond (SBUF), 13122
Note

QC 20190913

Available from: 2019-09-11 Created: 2019-09-11 Last updated: 2019-09-13Bibliographically approved
Wang, C., Sadeghian, P. & Sadrizadeh, S. (2019). Effect of staff number on the bacteria contamination in operating rooms with temperature-controlled airflow ventilation and turbulent mixing ventilation. In: Proceedings of Building Simulation 2019: 16th Conference of IBPSA. Paper presented at Building Simulation 2019: 16th Conference of IBPSA,2-4 September Rome Italy.
Open this publication in new window or tab >>Effect of staff number on the bacteria contamination in operating rooms with temperature-controlled airflow ventilation and turbulent mixing ventilation
2019 (English)In: Proceedings of Building Simulation 2019: 16th Conference of IBPSA, 2019Conference paper, Published paper (Refereed)
National Category
Civil Engineering
Research subject
Civil and Architectural Engineering, Fluid and Climate Theory
Identifiers
urn:nbn:se:kth:diva-263298 (URN)978-1-7750520-1-2 (ISBN)
Conference
Building Simulation 2019: 16th Conference of IBPSA,2-4 September Rome Italy
Note

QC 20191106

Available from: 2019-11-05 Created: 2019-11-05 Last updated: 2019-11-06Bibliographically approved
Polak, J., Afshari, A., Sadeghian, P., Wang, C. & Sadrizadeh, S. (2019). Improving the performance of heat valve ventilation system: A study on the provided thermal environment. Building and Environment, 164, Article ID UNSP 106338.
Open this publication in new window or tab >>Improving the performance of heat valve ventilation system: A study on the provided thermal environment
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2019 (English)In: Building and Environment, ISSN 0360-1323, E-ISSN 1873-684X, Vol. 164, article id UNSP 106338Article in journal (Refereed) Published
Abstract [en]

The current study presents and evaluates the performance of two types of supply air terminal devices applied in a heat valve ventilation (HVV) system with regard to the provided thermal environment in a room heated and ventilated by the HVV system. To that end, air temperature and air velocity patterns and local thermal discomfort due to draught were studied both experimentally and numerically. Using numerical simulations, parametric analysis was carried out for investigating the provided indoor thermal environment for a wider range of boundary conditions. The considered parameters included the influence of cold vertical surfaces, supply airflow rate and temperature, and room heating energy demand. The results showed that both of the applied air terminal devices could avoid temperature stratification within the occupied zone. The maximum air temperature difference between 0.1 and 1.8 m above the floor was 2.1 degrees C when using a circular valve placed in the external wall below the window and 2.6 degrees C in the case when the air was supplied through three nozzles located in the wall opposite to the window in the upper part of the room. In general, placing the air terminal device below the window provided more uniform air temperature distribution and contributed to the prevention of downdraught caused by a cold window surface. The outcomes of this study are relevant to selecting and designing ventilation and air heating systems for low-energy buildings.

Place, publisher, year, edition, pages
PERGAMON-ELSEVIER SCIENCE LTD, 2019
Keywords
Air heating, Air terminal device, Thermal environment, Air distribution, Temperature stratification, Draught rate
National Category
Building Technologies
Research subject
Civil and Architectural Engineering, Building Service and Energy Systems
Identifiers
urn:nbn:se:kth:diva-260993 (URN)10.1016/j.buildenv.2019.106338 (DOI)000484515300016 ()2-s2.0-85070748376 (Scopus ID)
Note

QC 20191010

Available from: 2019-10-10 Created: 2019-10-10 Last updated: 2019-11-26Bibliographically approved
Sadrizadeh, S. (2019). Numerical investigation of thermal comfort in an aircraft passenger cabin. In: E3S Web of Conferences: . Paper presented at 13th REHVA World Congress, CLIMA 2019; Bucharest; Romania; 26 May 2019 through 29 May 2019. EDP Sciences, 111, Article ID 01027.
Open this publication in new window or tab >>Numerical investigation of thermal comfort in an aircraft passenger cabin
2019 (English)In: E3S Web of Conferences, EDP Sciences, 2019, Vol. 111, article id 01027Conference paper, Published paper (Refereed)
Abstract [en]

This study presents the results of a pilot numerical study of the thermal comfort in the aircraft passenger cabin. The computations have been performed using the Computational Fluid Dynamics (CFD) technique. The overall thermal comfort at temperatures of 15 °C - 20 °C was discussed based on the PMV (Predicted Mean Vote) and PPD (Predicted Percentage of Dissatisfied) indexes. Results indicate that the air velocity and its direction toward the passengers have a considerable impact on their thermal comfort. However, a small variation in temperature has a limited effect on thermal sensation and thus do not jeopardize the overall thermal comfort.

Place, publisher, year, edition, pages
EDP Sciences, 2019
Series
E3S Web of Conferences, ISSN 2555-0403 ; 111
Keywords
Aircraft Passenger Cabin, Numerical Simulation, PMV (Predicted Mean Vote), PPD (Predicted Percentage of Dissatisfied), Thermal Comfort
National Category
Civil Engineering
Identifiers
urn:nbn:se:kth:diva-262527 (URN)10.1051/e3sconf/201911101027 (DOI)2-s2.0-85071877735 (Scopus ID)
Conference
13th REHVA World Congress, CLIMA 2019; Bucharest; Romania; 26 May 2019 through 29 May 2019
Note

QC 20191028

Available from: 2019-10-28 Created: 2019-10-28 Last updated: 2019-10-28Bibliographically approved
Ploskic, A., Wang, Q. & Sadrizadeh, S. (2018). Mapping Relevant Parameters for Efficient Operation of Low-Temperature Heating Systems in Nordic Single-Family Dwellings. Applied Sciences, 8(10), Article ID 1973.
Open this publication in new window or tab >>Mapping Relevant Parameters for Efficient Operation of Low-Temperature Heating Systems in Nordic Single-Family Dwellings
2018 (English)In: Applied Sciences, E-ISSN 2076-3417, Vol. 8, no 10, article id 1973Article in journal (Refereed) Published
Abstract [en]

The aim of this study was to map the parameters that have the greatest impact on the environmental impact of heating systems usually used in Nordic single-family dwellings. The study focused on mapping the technical requirements for efficient operation of heating systems in a broader context. The results suggest that the ability of a heating system to be operated with a low-temperature water supply depends to a large extent on the heating demand of a building. It was shown that an increase in the water flow rate in hydronic circuits would significantly increase the thermal efficiency from analyzed heating systems. This increase would not increase the pumping power need, nor would it create noise problems in distribution network if the distribution pipes and thermostatic valves were properly selected. However, this increase in water flow rate improved the efficiency of considered closed-loop heat pump. It was further shown that the efficiency of the heat pump could be additionally improved by halving the energy needs for the domestic hot-water and circulators. The main conclusion from this study is that exergy usage, CO2 emission and thereby environmental impact are significantly lower for heating systems that are operated with small temperature drops.

Place, publisher, year, edition, pages
MDPI, 2018
Keywords
low-temperature heating, energy efficiency, CO2 emissions, heat pump, hydraulic losses, system analysis
National Category
Medical Engineering
Identifiers
urn:nbn:se:kth:diva-239111 (URN)10.3390/app8101973 (DOI)000448653700268 ()2-s2.0-85055107835 (Scopus ID)
Note

QC 20181120

Available from: 2018-11-20 Created: 2018-11-20 Last updated: 2019-08-20Bibliographically approved
Wang, C., Sadrizadeh, S. & Holmberg, S. (2018). Numerical assessment of the influence of heat loads on the performance of temperature-controlled airflow in an operating room. In: 39th AIVC Conference: . Paper presented at 39th AIVC Conference "Smart Ventilation for Buildings", Antibes Juan-Les-Pins, France, 18-19 September 2018.
Open this publication in new window or tab >>Numerical assessment of the influence of heat loads on the performance of temperature-controlled airflow in an operating room
2018 (English)In: 39th AIVC Conference, 2018Conference paper, Published paper (Refereed)
Abstract [en]

Airborne bacteria-carrying particles (BCPs) in an operating room (OR) can cause post-operative infections in the patients. The ventilation system in the OR is crucial in removing or diluting airborne BCPs. This study numerically assessed a newly developed OR ventilation scheme – temperature-controlled airflow (TAF), with special focus on the influence of heat loads on the airflow and BCPs concentration. TAF supplies clean air at different temperature levels to different zones and establishes a high-momentum downward airflow pattern over the operating table. The results show that TAF is an efficient ventilation system that can provide good protection for the patients under low to moderately heavy heat loads. When the heat load is further increased to an extremely heavy level, the desired airflow pattern cannot be achieved and TAF becomes less efficient. The numerical results also suggest that the supply air temperature needs to be optimized according to the specific use conditions to maximize the performance of TAF.

National Category
Civil Engineering
Research subject
Civil and Architectural Engineering, Fluid and Climate Theory; Civil and Architectural Engineering, Fluid and Climate Theory
Identifiers
urn:nbn:se:kth:diva-263297 (URN)
Conference
39th AIVC Conference "Smart Ventilation for Buildings", Antibes Juan-Les-Pins, France, 18-19 September 2018
Note

QC 20191120

Available from: 2019-11-05 Created: 2019-11-05 Last updated: 2019-11-20Bibliographically approved
Wang, C., Holmberg, S. & Sadrizadeh, S. (2018). Numerical study of temperature-controlled airflow in comparison with turbulent mixing and laminar airflow for operating room ventilation. Building and Environment, 144, 45-56
Open this publication in new window or tab >>Numerical study of temperature-controlled airflow in comparison with turbulent mixing and laminar airflow for operating room ventilation
2018 (English)In: Building and Environment, ISSN 0360-1323, E-ISSN 1873-684X, Vol. 144, p. 45-56Article in journal (Refereed) Published
Abstract [en]

Operating room (OR) ventilation is crucial for reducing airborne bacteria-carrying particles (BCPs) concentration and thus preventing post-operative infections. A variety of ventilation schemes have been introduced to ORs. This study explores the effectiveness of a newly developed ventilation scheme, temperature-controlled airflow (TAF), with respect to reducing BCPs distribution and sedimentation in an OR. Comparisons are made with the conventional turbulent mixing and laminar airflow (LAF) ventilation. The study is conducted using Computational Fluid Dynamics (CFD) and Lagrangian particle tracking (LPT), with numerical models validated against literature data. The results reveal that TAF represents reliable and effective ventilation and can serve as an energy-efficient alternative to the LAF systems. The results also show that increasing ventilation rates alone will not always result in better control of BCPs distribution. Airflow patterns play an important role in removing and diluting airborne BCPs, so a specific analysis is necessary to each design of OR ventilation.

Place, publisher, year, edition, pages
PERGAMON-ELSEVIER SCIENCE LTD, 2018
Keywords
Operating room ventilation, Bacteria-carrying particles, Temperature-controlled airflow, Laminar airflow, Turbulent mixing ventilation
National Category
Construction Management
Identifiers
urn:nbn:se:kth:diva-238119 (URN)10.1016/j.buildenv.2018.08.010 (DOI)000447484300005 ()2-s2.0-85051404343 (Scopus ID)
Note

QC 20181205

Available from: 2018-12-05 Created: 2018-12-05 Last updated: 2019-11-05Bibliographically approved
Alsved, M., Civilis, A., Ekolind, P., Tammelin, A., Andersson, A. E., Jakobsson, J., . . . Londahl, J. (2018). Temperature-controlled airflow ventilation in operating rooms compared with laminar airflow and turbulent mixed airflow. Journal of Hospital Infection, 98(2), 181-190
Open this publication in new window or tab >>Temperature-controlled airflow ventilation in operating rooms compared with laminar airflow and turbulent mixed airflow
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2018 (English)In: Journal of Hospital Infection, ISSN 0195-6701, E-ISSN 1532-2939, Vol. 98, no 2, p. 181-190Article in journal (Refereed) Published
Abstract [en]

Aim: To evaluate three types of ventilation systems for operating rooms with respect to air cleanliness [in colony-forming units (cfu/m(3))], energy consumption and comfort of working environment (noise and draught) as reported by surgical team members. Methods: Two commonly used ventilation systems, vertical laminar airflow (LAF) and turbulent mixed airflow (TMA), were compared with a newly developed ventilation technique, temperature-controlled airflow (T(c)AF). The cfu concentrations were measured at three locations in an operating room during 45 orthopaedic procedures: close to the wound (<40 cm), at the instrument table and peripherally in the room. The operating team evaluated the comfort of the working environment by answering a questionnaire. Findings: LAF and T(c)AF, but not TMA, resulted in less than 10 cfu/m(3) at all measurement locations in the room during surgery. Median values of cfu/m(3) close to the wound (250 samples) were 0 for LAF, 1 for T(c)AF and 10 for TMA. Peripherally in the room, the cfu concentrations were lowest for T(c)AF. The cfu concentrations did not scale proportionally with airflow rates. Compared with LAF, the power consumption of T(c)AF was 28% lower and there was significantly less disturbance from noise and draught. Conclusion: T(c)AF and LAF remove bacteria more efficiently from the air than TMA, especially close to the wound and at the instrument table. Like LAF, the new T(c)AF ventilation system maintained very low levels of cfu in the air, but T(c)AF used substantially less energy and provided a more comfortable working environment than LAF. This enables energy savings with preserved air quality.

Place, publisher, year, edition, pages
W B SAUNDERS CO LTD, 2018
Keywords
Surgical site infection, BioTrak, Fluorescence, Energy efficiency, Temperature-controlled, ventilation, Air sampling
National Category
Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:kth:diva-223799 (URN)10.1016/j.jhin.2017.10.013 (DOI)000425104000013 ()29074054 (PubMedID)2-s2.0-85034808911 (Scopus ID)
Funder
Swedish Research Council Formas, 2014-1460Swedish Energy Agency, 2016-004864
Note

QC 20180307

Available from: 2018-03-07 Created: 2018-03-07 Last updated: 2018-03-07Bibliographically approved
Sadrizadeh, S., Nejad Ghafar, A., Halilovic, A. & Håkansson, U. (2017). Numerical, Experimental and Analytical Studies on Fluid Flow through a Marsh Funnel. Journal of Applied Fluid Mechanics, 10(6), 1501-1507
Open this publication in new window or tab >>Numerical, Experimental and Analytical Studies on Fluid Flow through a Marsh Funnel
2017 (English)In: Journal of Applied Fluid Mechanics, ISSN 1735-3572, E-ISSN 1735-3645, Vol. 10, no 6, p. 1501-1507Article in journal (Refereed) Published
Abstract [en]

This paper presents the application of computational fluid dynamics technique in civil and underground industries to evaluate fluid behaviour in a Marsh funnel. The numerical approach, based on computational fluid dynamics, simulated an incompressible two-phase Newtonian flow by means of the Volume-of-Fluid method. A complementary analytical proposed which provided a quick, field-ready method to assess the fluid field in the Marsh funnel. A supplemental experimental effort evaluated the results obtained from both the analytical calculation and numerical simulation. Results showed that the application of computational fluid dynamics technique gives the desired results in studying fluid flows in civil and underground industries. Proposed analytical solution is also capable of accurately predicting the fluid flow and thus can complement the experimental and numerical approaches. Further, the proposed analytical approach can be an alternative method for faster evaluation of fluid, although it needs to be calibrated with either the numerical or the experimental studies.

Place, publisher, year, edition, pages
ISFAHAN UNIV TECHNOLOGY, 2017
Keywords
Multiphase flow, Marsh funnel, CFD, Analytical solution, Experimental approach, Fluid flow simulation, Discharge coefficient, Cement-based grout
National Category
Applied Mechanics Geotechnical Engineering
Research subject
Civil and Architectural Engineering
Identifiers
urn:nbn:se:kth:diva-217475 (URN)000413507000001 ()2-s2.0-85030983634 (Scopus ID)
Note

QC 20171117

Available from: 2017-11-17 Created: 2017-11-17 Last updated: 2018-06-19Bibliographically approved
Sadrizadeh, S. & Ekolind, P. (2016). A new principle of ventilation system for operating rooms: Temperature-Controlled Air Flow. In: Proceedings of 12th REHVA world congress, CLIMA Conference. May 22-25, 2016; Aalborg - Denmark: . Paper presented at CLIMA 2016.
Open this publication in new window or tab >>A new principle of ventilation system for operating rooms: Temperature-Controlled Air Flow
2016 (English)In: Proceedings of 12th REHVA world congress, CLIMA Conference. May 22-25, 2016; Aalborg - Denmark, 2016Conference paper, Published paper (Refereed) [Artistic work]
Keywords
Temperature-Controlled Airflow Ventilation system, Operating theatre, Computational fluid dynamics, Infection, Airborne contamination
National Category
Medical Engineering Mechanical Engineering
Identifiers
urn:nbn:se:kth:diva-192000 (URN)
External cooperation:
Conference
CLIMA 2016
Note

QC 20160912

Available from: 2016-09-04 Created: 2016-09-04 Last updated: 2016-09-12Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-9361-1796

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