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67. Sen S., Sugiarto D., Rochman A. Komparasi Metode Multilayer Perceptron (MLP) dan Long Short Term Memory (LSTM) dalam Peramalan Harga Beras //Ultimatics: Journal Teknik Informatika. - 2020. - T. 12. - №. 1. - C. 35-41.
8. Agarap A. F. Deep learning using rectified linear units (relu) //arXiv preprint arXiv:1803.08375. -2018.
9. Uymin A. G., Melnikov D. A. REVIEW OF NETWORK INFRASTRUCTURE MODELING TOOLS FOR TRAINING SPECIALISTS IN ENLARGED SPECIALTY GROUPS 09.00. 00, 10.00. 00 //The science. Informatization. Technologies. Education, 2021, pp. 392-405.
THERMAL CALCULATION METHODS OF A SOLAR COLLECTOR FOR HOT WATER SUPPLY
Salmanova F.,
Doctor of Philosophy in Technical Sciences, Associate Professor,
Institute of Radiation Problems, Baku Mustafayeva R.,
Candidate of Technical Sciences, Associate Professor, Institute of Radiation Problems, Baku Mahmudova T.,
Candidate of Physical and Mathematical Sciences, Associate Professor,
Institute of Radiation Problems, Baku Yusupov I., Engineer
Institute of Radiation Problems, Baku Velizade I.
Engineer
Institute of Radiation Problems, Baku https://doi.org/10.5281/zenodo.6594864
Abstract
Thus, it can be seen that the use of flat solar collectors is an economically justified measure that can reduce the cost of traditional types of energy intended for heat supply. Solar collectors are the ideal solution to replace the seasonal load in heat supply, great for both warm and temperate climates. The advantages of using of a solar collector are ideal for seasonal operation in conditions of high solar insolation.
Keywords: Solar radiation, solar collector, heat engineering calculation, heat supply.
Solar heating systems (STS) are becoming more and more popular in many countries around the world. The success of STS is particularly impressive in Europe.
This problem acquired particular importance when, along with the development and increase in the efficiency of the use of traditional fuel and energy resources, there was a need to attract new energy sources such as solar energy and wind energy.
The energy of the sun is primarily characterized by constant renewal and, at the same time, its usage is not accompanied by a harmful effect on the environment.
The coastal strip of the Azerbaijani sector of the Caspian and especially the Absheron Peninsula have unique solar and wind resources suitable for widespread use of STS. A set of basic climatic requirements necessary for the rational and efficient use of solar energy is also considered.
In connection with this and the existing methodology of "State Citizenship", a thermal engineering calculation of the SVP was carried out according to the recommended data of the month with the highest intensity of solar radiation^ qi = 4439Bt/m2.
Assuming the inlet temperature t1=22°C ((for the month of June), the temperature at the outlet of the solar collector t2=55°C the ambient temperature tcp=25°C h and the efficiency factor n=0,44.
All types of installations with backup sources are calculated according to the data of the month with the largest amount of solar radiation over the period of operation, and systems without a backup source are calculated from the smallest.
The required area of the sun-absorbing surface of the installation collectors without backups A, m2, should be determined by the formula:
A = G / X g, ( 1 )
Where G is the daily consumption of hot water in the hot water supply system G, kg, is taken according to SNiP. gi - hourly productivity of the installation, referred to 1 m2 of the surface of the solar collector, kg / m2; i - estimated hours of operation of the installation.
In case of uneven consumption of hot water by months in installations without backups, the calculation of the area of solar collectors should be performed according to the daily consumption of hot water each month and take the largest of the obtained areas.
The hourly productivity of the installation, kg/m2, is determined by the formula:
(2)
0.86 U
ln
lmaxl-t! tmaxl-t2
Where U is the reduced heat loss coefficient of the solar collector (W/m2 • K), in the absence of passport data, 8 (W/m2 • K) can be accepted for single-glass collectors and 5 (W/m2 • K) for double-glass; tx, t2 coolant
temperature at the inlet and outlet of the solar collector, °C.
The temperature t2 at the inlet and outlet is determined by the formula:
t2 = tvv2 + 5 0C,
where U2 is the required hot water temperature.
The inlet temperature is determined by the formula:
ti = twi + 5 0C,
where tw1— is the required cold water temperature.
In single circuit systems ti = W and t2 = tvv2
During the first hour of operation of the unit, the inlet temperature is assumed to be equal to the temperature of the water in the storage tank.
When the solar collectors deviate from the southern orientation to 15°, the amount of absorbed radiation decreases by 5%, with a deviation of up to 30-10%.
The area of the sun-absorbing surface of installations with backup A, m2, should be determined by the formula:
1.16G(tVV2-tvvi)
A =■
(3)
where qt - is the intensity of the incident solar radiation in the plane of the collector, W/m2, is determined by in the range from 08:00 to 17:00 for solar collectors of southern orientation. With a deviation from south to east or west for every 16 °, the time interval begins earlier or later by 1 hour; q- CUP (coefficients of useful performance) of the solar hot water installation.
The coefficients of useful performance of the installation is determined by the formula:
W[0,5 (ti + t2)-ten
n = 0,8 {d
(4)
where 6 - is the reduced optical characteristic of the collector. In the absence of passport data, it can be taken equal to 0.73 for single-glass collectors and 0.63 for double-glass collectors; te — average daily air temperature °C.
If the maximum hourly heating capacity of the solar hot water installation with forced circulation is higher than required according to the water withdrawal schedule, then storage tanks must be installed in the installations. The volume of the storage tank V, m3, should be determined according to the daily schedules
for heating water in the installation and water consumption, and in their absence, depending on the climatic region according to the formula V = (0.06 -0.08) A, taking a larger value for 1U climatic district.
With a variable flow rate of the coolant in the heat-receiving circuit and the heated water circuit, the pumps are selected according to the maximum flow rate. At a constant flow rate of the coolant, its specific flow rate should be taken in the range of 20-40 kg (m2 h).
When designing installations with a variable flow rate of the coolant, the calculation of heat exchangers should be made according to the average hourly values of the flow rates of water and coolant.
The calculation of fuel savings due to the use of solar energy should be made according to the formula:
B = 0.0342 Q /%ot
where Q - the total amount of heat GJ / year, generated by the solar hot water supply installation for the season (year), determined according to Annex 4; qpot is the efficiency of the heat source to be replaced.
The calculation of the solar hot water installation is performed by the hourly sums of direct and diffuse solar radiation and the outdoor air temperature. The magnitude of the intensity of solar radiation, the temperature of the outside air is taken, as a rule, according to the "Handbook on climate", Gidrometeoizdat.
The intensity of the incident solar radiation for any spatial position of the solar collector and each hour of day light hours qi, W / m2 should be determined by the formula:
qi = Ps Is+PdId
where Is - is the intensity of direct solar radiation incident on a horizontal surface, W/m2 ID - intensity of scattered solar radiation incident on a horizontal surface, W/m2;
Ps,Pd - - solar collector position coefficients for direct and diffuse radiation, respectively.
The coefficients of the position of the solar collector for scattered radiation should be determined by the formula:
PD=cos2b/2
where b - is the angle of inclination of the solar collector to the horizon.
The coefficients of the position of the solar collector Ps for direct solar radiation should be determined from the table in this appendix.
Angle of inclination of the collector to the horizon b, deg Months
I II III IV V VI VII VIII IX X XI XII
Latitude 40°
25 i,76 1,49 1,30 1,13 1,04 1 1,01 1,08 1,22 1,4 1,66 1,85
40 2,24 1,72 1,36 1,11 0,97 0,90 0,93 1,03 1,24 1,55 2,03 2,45
55 2,46 1,79 1,33 1,03 0,86 0,78 0,81 0,94 1,17 1,56 2,18 2,72
90 2,30 1,48 0,91 0 0 0 0 0 0,75 1,17 1,96 2,61
Latitude 45°
30 2,14 1,71 1,42 1,19 1,07 1,02 1,04 1,13 1,30 1,56 1,96 2,31
45 2,86 1,99 1,49 1,17 1,00 0,92 0,95 1,08 1,33 1,74 2,47 3,27
60 3,13 2,07 1,45 1,09 0,89 0,8 0,84 0,99 1,26 1,76 2,66 3,64
90 3,04 1,81 0,99 0,71 0 0 0 0 0,89 1,37 2,5 3,63
The reduced intensity of absorbed solar radiation, W/m2, should be determined by the formula: ^=0,96 (Ps ei/s+pDeD/D) where 05 and 0D - respectively are the given optical characteristics of the solar collector for direct and diffuse solar radiation. In the absence of passport data, the following can be accepted: 0S= 0,74; 0D =0,64 - for single-glass and 0S =0,63; 0D = 0,42- for double-glazed solar collectors.
The annual (seasonal) efficiency is determined according to the graph of the area of solar collectors A,
Solar hot water
m2, / (GJday), and the capacity of the battery tank - m3 / (GJday), per unit of daily heat load of hot water supply, which are calculated by the formulas:
Â=10M/[4,19G(tW2 - twi)]; 7=1067/[4,19G(tW2 - tW1)]; The total amount of heat GJ generated by the plant
is determined by the formula: Q
where z - is the number of months of plant operation; j - is the number of days in a month. installations
Dependence of the seasonal of the solar CUP of solar hot water installation on the values of A and V..
REFERENCES:
1. Установки солнечного водоснабжения нормы проектирования. Москва 1988
2. Саламов О.М., Аббасова(Салманова) Ф.А., Рзаев П.Ф. Расчет солнечной водоподогреватель-ной системы для горячего водоснабжения сельской семьи. Международный научный журнал «Альтернативная энергетика и экология» Москва, 2006, № 10, s.s. 30-36.
3. Тарнитевски Б.В. Оценки эффективности применения солнечного теплоснабжения в Росси. Теплоэнергетика №5, 1996г.
4. ГОСТ Р 51595-2000 "Нетродиционная энергетика" Солнечная энергетика коллекторы солнечные. Общие технические условия.
5. У. Бекман, С. Клейн, Дж. Даффи. Расчет систем солнечного теплоснабжения. Москва, "Энергоатомиздат" 1982.
