Influence of Meteorological Factors on the Thermal Loss Coefficient of Light-Absorbing Heat Exchange Panels of Flat-Plate Solar Water Heating Collectors through Transparent Coatings of Their Casings

Opportunities and prospects for the use of solar energy for refrigeration of public buildings

“…The temperature of the water chilled in this way is 3-4 ℃ lower than the temperature of the water chilled during the day, and the final water temperature is close to the saturation temperature of the outside air. Another advantage of night-time evaporative cooling, compared to daytime evaporative cooling, is the possibility of additional water cooling by using the effective radiation of the water surface to the night sky, the conditional temperature of which, determined according to [5][6][7][8] (Eq. 1 and 2).…”

“…In accordance with the principle calculation diagram in Figure 1, the differential equations (Eq. [3][4][5][6][7][8][9][10][11][12] for the heat balance of water flowing down the sloping plane is given. For simplicity, the friction forces between the air and the surface of the flowing water, and between the surfaces of the solid inclined plane on which the water flows and the surface of the flowing water are neglected [15][16][17][18][19][20].…”

“…In practical calculations to determine the value of 𝑡 𝑤 ′′ (with given values of 𝑡 𝑤 ′ and 𝐺 𝑎 ), the value of 𝛼 𝑘 in (19) depending on the wind speed can be determined from the Ma Adams formula [5,6] (Eq. 20).…”

“…where 𝜗wind speed, 𝑚 𝑠 ⁄ . The value of the mass transfer coefficient for water evaporation from a free surface, related to the difference between the partial pressures 𝑃 𝑤 and 𝑃 о , when the air flow is directed along the surface of the evaporation mirror, can be determined from the expression [11][12][13][14] The value of the radiant heat transfer between the surface of water flowing down a sloping plane and the sky 𝛼 𝑟𝑎𝑑 in ( 18) is determined from [6] (Eq. 22 and 23)…”

“…The use of evaporative cooling water in the air stream as a natural source of cooling in air conditioning systems is generally assumed if the calculated values of relative humidity (𝜑 о ) and dew point temperature (𝑡 р ) of the warm season outdoor air for parameters 𝐵 each separately do not exceed 65% and 18 ℃, respectively [3,4]. The climatic conditions in most regions of the Republic in summer are characterised by low relative humidity at high outdoor temperatures according to the dry thermometer (𝑡 о ), which allows the use of 1142 (2023) 012001 IOP Publishing doi:10.1088/1755-1315/1142/1/012001 2 air conditioning systems based on water cooling by adiabatic evaporation in the air flow for facilities with small heat losses [5,6]. One of the possible ways to increase the efficiency of the system is to use night-time evaporative cooling of water with its subsequent accumulation for daytime cooling in thermally insulated accumulators.…”