On the Ventilation Performance of Low Momentum Confluent Jets Supply Device in a Classroom
The performance of three different confluent jets ventilation (CJV) supply devices was evaluated in a classroom environment concerning thermal comfort, indoor air quality (IAQ) and energy efficiency. The CJV supply devices have the acronyms: high-momentum confluent jets (HMCJ), low-momentum confluen...
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| Format: | Article |
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MDPI AG
2020-10-01
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| Series: | Energies |
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| Online Access: | https://www.mdpi.com/1996-1073/13/20/5415 |
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| author | Harald Andersson Alan Kabanshi Mathias Cehlin Bahram Moshfegh |
| author_facet | Harald Andersson Alan Kabanshi Mathias Cehlin Bahram Moshfegh |
| author_sort | Harald Andersson |
| collection | DOAJ |
| description | The performance of three different confluent jets ventilation (CJV) supply devices was evaluated in a classroom environment concerning thermal comfort, indoor air quality (IAQ) and energy efficiency. The CJV supply devices have the acronyms: high-momentum confluent jets (HMCJ), low-momentum confluent jets (LMCJ) and low-momentum confluent jets modified by varying airflow direction (LMCJ-M). A mixing ventilation (MV) slot jet (SJ) supply device was used as a benchmark. Comparisons were made with identical set-up conditions in five cases with different supply temperatures (T<sub>S</sub>) (16–18 °C), airflow rates (2.2–6.3 ACH) and heat loads (17–47 W/m<sup>2</sup>). Performances were evaluated based on DR (draft rating), PMV (predicted mean vote), ACE (air change effectiveness) and heat removal effectiveness (HRE). The results show that CJV had higher HRE and IAQ than MV and LMCJ/LMCJ-M had higher ACE than HMCJ. The main effects of lower T<sub>s</sub> were higher velocities, DR (HMCJ particularly) and HRE in the occupied zone as well as lower temperatures and PMV-values. HMCJ and LMCJ produce MV conditions at lower airflow rates (<4.2 ACH) and non-uniform conditions at higher airflow rates. LMCJ-M had 7% higher HRE than the other CJV supply devices and produced non-uniform conditions at lower airflow rates (<3.3 ACH). The non-uniform conditions resulted in LMCJ-M having the highest energy efficiency of all devices. |
| first_indexed | 2024-03-10T15:34:31Z |
| format | Article |
| id | doaj.art-6cb77f3ebf5240e4b9b9c19afd298be6 |
| institution | Directory Open Access Journal |
| issn | 1996-1073 |
| language | English |
| last_indexed | 2024-03-10T15:34:31Z |
| publishDate | 2020-10-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Energies |
| spelling | doaj.art-6cb77f3ebf5240e4b9b9c19afd298be62023-11-20T17:23:32ZengMDPI AGEnergies1996-10732020-10-011320541510.3390/en13205415On the Ventilation Performance of Low Momentum Confluent Jets Supply Device in a ClassroomHarald Andersson0Alan Kabanshi1Mathias Cehlin2Bahram Moshfegh3Department of Building Engineering, Energy Systems and Sustainability Science, University of Gävle, 80176 Gävle, SwedenDepartment of Building Engineering, Energy Systems and Sustainability Science, University of Gävle, 80176 Gävle, SwedenDepartment of Building Engineering, Energy Systems and Sustainability Science, University of Gävle, 80176 Gävle, SwedenDepartment of Building Engineering, Energy Systems and Sustainability Science, University of Gävle, 80176 Gävle, SwedenThe performance of three different confluent jets ventilation (CJV) supply devices was evaluated in a classroom environment concerning thermal comfort, indoor air quality (IAQ) and energy efficiency. The CJV supply devices have the acronyms: high-momentum confluent jets (HMCJ), low-momentum confluent jets (LMCJ) and low-momentum confluent jets modified by varying airflow direction (LMCJ-M). A mixing ventilation (MV) slot jet (SJ) supply device was used as a benchmark. Comparisons were made with identical set-up conditions in five cases with different supply temperatures (T<sub>S</sub>) (16–18 °C), airflow rates (2.2–6.3 ACH) and heat loads (17–47 W/m<sup>2</sup>). Performances were evaluated based on DR (draft rating), PMV (predicted mean vote), ACE (air change effectiveness) and heat removal effectiveness (HRE). The results show that CJV had higher HRE and IAQ than MV and LMCJ/LMCJ-M had higher ACE than HMCJ. The main effects of lower T<sub>s</sub> were higher velocities, DR (HMCJ particularly) and HRE in the occupied zone as well as lower temperatures and PMV-values. HMCJ and LMCJ produce MV conditions at lower airflow rates (<4.2 ACH) and non-uniform conditions at higher airflow rates. LMCJ-M had 7% higher HRE than the other CJV supply devices and produced non-uniform conditions at lower airflow rates (<3.3 ACH). The non-uniform conditions resulted in LMCJ-M having the highest energy efficiency of all devices.https://www.mdpi.com/1996-1073/13/20/5415experimental investigationsconfluent jets ventilationmixing ventilationventilation efficiencythermal comfortheat removal effectiveness |
| spellingShingle | Harald Andersson Alan Kabanshi Mathias Cehlin Bahram Moshfegh On the Ventilation Performance of Low Momentum Confluent Jets Supply Device in a Classroom Energies experimental investigations confluent jets ventilation mixing ventilation ventilation efficiency thermal comfort heat removal effectiveness |
| title | On the Ventilation Performance of Low Momentum Confluent Jets Supply Device in a Classroom |
| title_full | On the Ventilation Performance of Low Momentum Confluent Jets Supply Device in a Classroom |
| title_fullStr | On the Ventilation Performance of Low Momentum Confluent Jets Supply Device in a Classroom |
| title_full_unstemmed | On the Ventilation Performance of Low Momentum Confluent Jets Supply Device in a Classroom |
| title_short | On the Ventilation Performance of Low Momentum Confluent Jets Supply Device in a Classroom |
| title_sort | on the ventilation performance of low momentum confluent jets supply device in a classroom |
| topic | experimental investigations confluent jets ventilation mixing ventilation ventilation efficiency thermal comfort heat removal effectiveness |
| url | https://www.mdpi.com/1996-1073/13/20/5415 |
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