Balcony wall temperature is not enough reason analysis
Currently, many manufacturers of flat panel solar water heater Balcony wall there is no hot water, particularly in autumn and winter performance even more.
Why is this the case? There are several reasons.
1, the ratio of collector area and tank capacity is unreasonable. Balcony wall heaters are flat-plate collector, all glass tube type, heat pipe, U-shaped tube, no matter what kind of collector are present lighting utilization of floor space. Although solar energy is clean, free energy, but energy density is low, to 17MJ / (m. D) of sunshine, for example, 1 m 100% solar heat all day into hot water (temperature 40 degrees), and only then Only 102L. As the collector\\ s own area-efficient light collection efficiency, the balcony of the solar energy area, the balcony of illumination time, light intensity and other factors, resulting in heat gain from solar energy is less than the design heat load, combined with cold temperatures fall and winter seasons lower, but the bath temperature is really demanding, with the heat load increases, the water pressure tank capacity of the same, do not start the case of electric heating, will be lower than in other seasons.
2, balcony hanging solar water tank heat exchanger heat transfer efficiency is low. According to Fourier law, heat transfer efficiency of the contact area with the heat exchanger, flow rate, heat transfer material closely related to the current balcony wall heat exchanger in the form of solar water tank with small tank, jacket, coil several forms. Heat transfer area, the jacket and coil heat exchanger is larger than a small tank, flow rate, the forced circulation system is better than the natural cycle, heat transfer material, the most use of enamel liner jacket water tank, copper pipe better than the enamel coil.
3, medium circulation line is unreasonable. Currently the balcony wall, mostly natural circulation , the natural cycle of the bit is no external power, relying on the system itself, the fluid density difference between the automatic cycle. However, the loop natural circulation system must be higher than the collector tank, because the system itself, the fluid dynamics of the formation of very small density difference, it must be taken to reduce a variety of fault system vascular resistance. Such as: selection of a larger diameter, piping as short as possible, turning as little as possible, to prevent anti-slope, causing the gas block and so on.
4, the collector system, poor insulation, heat loss. To solve the pressure, antifreeze and other issues, commonly used in solar water heater Balcony wall secondary heat exchanger systems, pipe insulation do a good job, good selection of high performance solar thermal collector, solar collectors are effective in reducing some of the heat loss to significantly improve the efficiency of the system.