Experimental Performance of an Advanced Air-Type Photovoltaic/Thermal (PVT) Collector with Direct Expansion Air Handling Unit (AHU)
Bibliographic record
Abstract
In addition to electrical energy generation, photovoltaic/thermal (PVT) systems utilize heat from building-integrated photovoltaic (BIPV) modules for domestic hot water and space heating. In other words, a PVT system can improve the electricity efficiency of BIPVs while using the waste heat of BIPVs as a source of thermal energy for the building. By generating thermal and electrical energies simultaneously, PVT systems can improve the utilization of solar energy while enhancing the energy performance of buildings. To optimize the performance of an air-type PVT collector, it is necessary for the system to extract more heat from the PV module. Consequently, this approach decreases PV temperature to improve PV electrical energy generation. The thermal and electrical performance of an air-type PVT collector depends on its design, which affects airflow and heat transfer. Moreover, the performances of the PVT collector can differ according to the coupled facility in the building. In this study, the thermal and electrical performances of an advanced air-type PVT collector with a direct expansion air handling unit (AHU) were analyzed experimentally. For this purpose, six prototypes of an advanced air-type PVT collector were developed. Furthermore, a direct expansion AHU with a heat recovery exchanger (HRX) was designed and built. The advanced PVT collectors with a total capacity of 740 Wp were installed in an experimental house and were coupled to the direct expansion AHU system with a maximum airflow of 700 CMH. The performance of PVT collectors was analyzed and compared with the BIPV system. Results showed that building-integrated photovoltaic/thermal (BIPVT) collectors produced 30 W more power than the BIPV system. When operating the AHU system, the temperature of the BIPVT collector was generally lower than the BIPV. The maximum difference in temperature between BIPVT and BIPV was about 22 °C. During winter season, the BIPVT collector supplied preheated air to the AHU. The supplied air temperature from the BIPVT collector reached 32 °C, which was 15 °C higher than outdoor air temperature.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".