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Steen Englund, JessikaORCID iD iconorcid.org/0000-0002-5822-4838
Publications (3 of 3) Show all publications
Steen Englund, J., Cehlin, M., Akander, J. & Moshfegh, B. (2020). Measured and Simulated Energy Use in a Secondary School Building in Sweden — A Case Study of Validation, Airing, and Occupancy Behaviour. Energies, 13(9), Article ID 2325.
Open this publication in new window or tab >>Measured and Simulated Energy Use in a Secondary School Building in Sweden — A Case Study of Validation, Airing, and Occupancy Behaviour
2020 (English)In: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 13, no 9, article id 2325Article in journal (Refereed) Published
Abstract [en]

In this case study, the energy performance of a secondary school building from the 1960s in Gävle, Sweden, was modelled in the building energy simulation (BES) tool IDA ICE version 4.8 prior to major renovation planning. The objectives of the study were to validate the BES model during both occupied and unoccupied periods, investigate how to model airing and varying occupancy behaviour, and finally investigate energy use to identify potential energy-efficiency measures. The BES model was validated by using field measurements and evidence-based input. Thermal bridges, infiltration, mechanical ventilation, domestic hot water circulation losses, and space heating power were calculated and measured. A backcasting method was developed to model heat losses due to airing, opening windows and doors, and other occupancy behaviour through regression analysis between daily heat power and outdoor temperature. Validation results show good agreement: 3.4% discrepancy between space heating measurements and simulations during an unoccupied week. Corresponding monthly discrepancy varied between 5.5% and 10.6% during three months with occupants. Annual simulation indicates that the best potential renovation measures are changing to efficient windows, improved envelope airtightness, new controls of the HVAC system, and increased external wall thermal insulation.

Place, publisher, year, edition, pages
MDPI, 2020
Keywords
building energy simulation; school building; field measurements; validation; airing; windows and door opening; occupancy behaviour; energy efficiency measures
National Category
Energy Engineering
Research subject
Sustainable Urban Development
Identifiers
urn:nbn:se:hig:diva-32286 (URN)10.3390/en13092325 (DOI)
Funder
Knowledge Foundation
Available from: 2020-05-08 Created: 2020-05-08 Last updated: 2020-05-11Bibliographically approved
Steen Englund, J., Akander, J., Björling, M. & Moshfegh, B. (2017). Assessment of Airflows in a School Building with Mechanical Ventilation Using Passive Tracer Gas Method (1ed.). In: Sayigh, Ali (Ed.), Mediterranean Green Buildings & Renewable Energy: Selected Papers from the World Renewable Energy Network’s Med Green Forum: (pp. 619-631). Springer
Open this publication in new window or tab >>Assessment of Airflows in a School Building with Mechanical Ventilation Using Passive Tracer Gas Method
2017 (English)In: Mediterranean Green Buildings & Renewable Energy: Selected Papers from the World Renewable Energy Network’s Med Green Forum / [ed] Sayigh, Ali, Springer, 2017, 1, p. 619-631Chapter in book (Refereed)
Abstract [en]

The focus of this study is to assess the airflows in a school building built in 1963 in Gävle, Sweden, which is subject to energy conservation measures (ECMs) in a forthcoming renovation. Today, the school building is mainly ventilated by several mechanical ventilation systems, which are controlled by a constant air volume (CAV) strategy. Schedules and presence sensors impose a high operation mode during the day and a low operation mode at night, on weekends and on holidays. The homogeneous tracer gas emission method with passive sampling is used to measure the average local mean age of air (τ) during different operation modes. Temperature, relative humidity and CO2 concentration are simultaneously measured. The calculated relative uncertainty for the average local mean age of air in every measured point is approx. ±20 %. The results during low operation mode show an average value of τ of approx. 8.51 h [corresponding to 0.12 air changes per hour (ACH)], where τ in various zones ranges between 2.55 and 16.37 h (indicating 0.06–0.39 ACH), which is related to the unintentional airflow in the school. The results during mixed operation mode show an average value of τ of approx. 4.60 h (0.22 ACH), where τ in various zones ranges between 2.00 and 8.98 h (0.11–0.50 ACH), which is related to both unintentional and intentional airflows in the school. Corridors, basement and attic rooms and entrances have lower τ compared to classrooms, offices and other rooms. High maximums of the CO2 concentration in some rooms indicate an imbalance in the mechanical ventilation systems. During a regular school week of mixed operation, which includes both high and low operation modes, it is found that mainly the low operation modes show up in the results. The dynamics of the highly varying airflows in the building cannot be identified using the passive sampling technique.

Place, publisher, year, edition, pages
Springer, 2017 Edition: 1
Keywords
Homogeneous tracer gas emission technique, Local mean age of air, Air change rate, Air leakage, School building
National Category
Energy Systems
Identifiers
urn:nbn:se:hig:diva-24006 (URN)10.1007/978-3-319-30746-6_47 (DOI)2-s2.0-85029047826 (Scopus ID)978-3-319-30745-9 (ISBN)978-3-319-30746-6 (ISBN)
Note

Entire publication doi: 10.1007/978-3-319-30746-6

Available from: 2017-05-12 Created: 2017-05-12 Last updated: 2018-03-13Bibliographically approved
Björling, M., Akander, J. & Steen Englund, J. (2016). On Measuring Air Infiltration Rates Using Tracer Gases in Buildings with Presence Controlled Mechanical Ventilation Systems. In: E. Van Kenhove, J. Laverge, P. De Vlieger (Ed.), Indoor Air 2016: The 14th International Conference of Indoor Air Quality and Climate, July 3-8 2016, Ghent, Belgium: Conference Proceedings. Paper presented at Indoor Air 2016, 14th International Conference of Indoor Air Quality and Climate, Ghent, Belgium, 3-8 July 2016. ISIAQ, Article ID 875.
Open this publication in new window or tab >>On Measuring Air Infiltration Rates Using Tracer Gases in Buildings with Presence Controlled Mechanical Ventilation Systems
2016 (English)In: Indoor Air 2016: The 14th International Conference of Indoor Air Quality and Climate, July 3-8 2016, Ghent, Belgium: Conference Proceedings / [ed] E. Van Kenhove, J. Laverge, P. De Vlieger, ISIAQ , 2016, article id 875Conference paper, Published paper (Refereed)
Abstract [en]

The ventilation and air leakage of a school building was investigated. Information was collected from the parameters of the mechanical ventilation system and from measurements of the local mean age of air using the homogeneous emission method. While the average local mean ages of air can be accurately measured by passive integrative samplers, the estimation of the average room specific air change rate by taking the inverse of the measured average local mean age of air did not give correct results. The main problem is that integrative sampling represents a linear averaging process that is inappropriate to capture the average of nonlinearly related properties. This problem is accentuated when the ventilation rates for different periods differ a lot. A simple computational model was developed to discuss the system behavior. A partial solution to the measurement problem is to actively sample the different populations of air change rates separately.

Place, publisher, year, edition, pages
ISIAQ, 2016
Keywords
air infiltration, local mean age of air, room specific ventilation rate, ACH
National Category
Environmental Analysis and Construction Information Technology
Identifiers
urn:nbn:se:hig:diva-22676 (URN)978-0-9846855-5-4 (ISBN)
Conference
Indoor Air 2016, 14th International Conference of Indoor Air Quality and Climate, Ghent, Belgium, 3-8 July 2016
Available from: 2016-11-11 Created: 2016-10-28 Last updated: 2018-03-13Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0002-5822-4838

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