No.
Solar water heaters can be used on cloudy and rainy days. The vacuum tubes of solar water heaters are installed on the roof. Vacuum tubes can also produce heat in cloudy and rainy weather. However, compared to sunny days, the water temperature will not heat up as quickly and the temperature may not reach. that of sunny days. There are many brands of solar water heaters, and their water replenishment can be automatic or semi-automatic. At night we use the hot water which has been isolated in the water storage tank. Generally, the heat collection area and hot water storage capacity of solar water heaters are configured according to needs, so there is no need to worry about the situation where there will be no no hot water.
Can solar energy at 15 degrees provide heat?
Hellor, if the solar energy is not used for a long time, it is better to fill it with water. is a good protection for glass tubes and drums. Of course you can also drain the water. Air drying will have a slight impact on the tube, including heat absorption effect. If possible, you can also cover the tube with glass.
Of course.
The sun is a good antiseptic and soft medicine for all clothes. However, it is best not to expose clothes that are easy to fade and fade to the sun for a long time. If you really like the smell of sunshine and want to dry it, turn the clothes inside out and dry them. Discoloration inside will not affect the effect outside. However, a solar temperature of 15 degrees is not considered excessive exposure and can speed up the drying of clothes.