Hello, the solar hot water system temperature difference circulation pump needs to be calculated. First, choose the water pump according to your own calculation results, and then compare it with the pump performance curve!
1. Design flow rate
For solar water heating systems, the heat collection circulation pipeline is a closed loop, so the calculated flow rate of the pipeline is the circulation flow rate, calculated according to the formula following:
In the formula: q—circulation flow rate, L/h
QS—circulation flow rate of the collector, due to uncertainty ; solar radiation, combined heat. The circulation rate of the water system heat collection cannot be calculated accurately. Generally, the collector flow rate per square meter is 0.01-0.02 L/s, or 36-72 L/(h·㎡). ).
A—The total heat collection surface of the solar collector.
AboutBased on the differences in solar irradiation in various places and Siji Muge's many years of engineering design experience, the circulation rate of heat collection is generally selected according to the following table.
Table 1.1.1 of collector circulation flow rate value table
Regional collector circulation flow rate Qs L/(h·㎡)
Qinghai , Tibet 70~ 80
Inner Mongolia, Xinjiang 60
Other regions 50
2. Water pressure required for heat collection circulation
Water pressure of heat recovery circulation pump The formula to calculate the head is:
H=H1+H2+H3
In the formula, H——the water pressure required by the water supply system in the building, kPa;
H1 — —The starting point of the water pump suction pipe to the worst water distribution point (in the water collection circulation systemheat, if the water pressure of a certain water distribution system is satisfied, the pressure of any other water point in the system can also be satisfied, then this point is called the system The distribution point of 'worst case water.) The required hydrostatic pressure at the height of the location, kPa;
< p> H2 ——The water supply line from the starting point of the suction pipe of the water pump to the worst-case water distribution point calculates both the entire length and the local area of the water height. Sum of losses, kPa;
H3——The outlet head kPa required by the worst-case water distribution point. Among them, H3 can be taken at 2-3 m depending on experience.