Design, Construction, and Thermodynamic Analysis of a Direct-Expansion Solar Assisted Heat Pump for Cold Climates
Bibliographic record
Abstract
Abstract Direct expansion solar assisted heat pump (DX-SAHP) systems have the potential to provide the heat load required for domestic hot water (DHW) sustainably and with minimum emissions. DX-SAHPs utilize a solar thermal collector to evaporate a working fluid. By using less energy in the process, these systems can achieve higher coefficients of performance (COP) than those afforded by conventional air source heat pumps. With Calgary possessing the highest solar potential in Canada of about 2396 hours of sunlight available 333 days a year [1], the implementation of such systems would make technical and economic sense. In this paper, the design, fabrication, and testing of a DX-SAHP system for cold climates is presented. A mathematical model representing the system was developed by combining the Hottel-Whillier-Bliss equation for the solar collector and a control volume analysis using the first law of thermodynamics for the heat pump cycle. Theoretical results demonstrate that a COP in the range of 3.4–4.5 is achievable. With the promising theoretical results, an experimental test setup was designed, constructed, and instrumented to determine the long-term performance of a DX-SAHP under local climatic conditions.
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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 | 0.000 | 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 | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".