Daytime heat losses and coolant temperatures at the outlet of flat-plate solar collectors (SC) are studied taking into account the variability of the density of incident solar radiation on the SC. The studies were carried out on the basis of the developed one-dimensional three-layer distributed non-stationary thermal model of a flat single-channel SC with a non-selective receiver, which takes into account temperature changes along the length of the SC. It is shown that the main heat losses in the SC in summer are up to 78% by radiation from the transparent enclosure (TE), and from the thermal insulation of the bottom 15%, convective heat loss is about 7%, of which about 5.5% in the TE and 1.5% in the insulation. These indicators and the temperature of the coolant at the outlet of the SC have variable values during the day, which must be taken into account when applying the efficiency factor of the SC. It is shown that the improvement of the thermal characteristics of the TE, first of all, depends on the possibility of electromagnetic radiation from the TE. Reducing the heat losses of the SC by increasing the thickness of the thermal insulation is limited due to small thermal effects.
| Mualliflar | Кличев, Ш.И., Бахрамов, С.А., Кенжаев, И.Г., Турсунбаев, Ж.Ж., Маразаков, Ш.А. |
|---|---|
| Jurnal | O‘zbekiston fizika jurnali |
| Nashr sanasi | 2023-10-07 |
| Jild | 25 |
| Son | 3 |
| Til | Rus |
| DOI | 10.52304/.v25i3.445 |
DOI: 10.52304/.v25i3.445 · Maqolaning asl sahifasi
солнечное излучение, нестационарный радиационный и конвективный теплообмен, метод конечных разностей, граничные условия, solar radiation, nonstationary radiative and convective heat transfer, finite difference method, boundary conditions
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