Experimental Investigation of the Thermal Performance of a Prototype Direct-Expansion Solar-Assisted Heat Pump System in a Cold Climate
Bibliographic record
Abstract
Abstract Direct-expansion solar-assisted heat pumps (DX-SAHP) take advantage of solar energy to enhance the efficiency of conventional air-source heat pumps. However, their performance in very cold climates is not well understood. In this study, a prototype DX-SAHP is developed to experimentally characterize performance under realistic operating conditions. The system consists of a 2.3 m2 solar collector with a serpentine heat exchanger as an evaporator, a scroll compressor with a rated power input of 0.6 kW, an expansion valve, a coaxial coil heat exchanger as the condenser, and a 178 L water storage tank. A set of experiments was conducted under realistic outdoor air conditions to assess the system’s thermal performance. The system achieved an average coefficient of performance (COP) of 3.1 on a sunny day in winter to raise the water tank temperature from 16.1°C to 50.3°C in 4.5 hours. Conversely, the minimum average COP of 3.0 was recorded on an overcast summer day, raising the water temperature from 27.3°C to 49.5°C in 3.5 hours, while the system achieved its highest average COP of 3.44 on a sunny summer day. The highest instantaneous COP during the operation was 4.33, recorded in summer. However, the system was unable to operate continuously during overcast winter days, due to inadequate available thermal energy.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".