When I was in elementary school about ten years ago, our house used solar water heaters. Solar water heaters were particularly popular in China at that time, and almost all new buildings were equipped with solar water heaters because people were glad to contribute to the environment and save on electricity bills. But about eight years later, our family abandoned solar water heaters and switched to natural gas for water heating.
Although I know this, I have never thought about why. Therefore, when I knew that solar energy was involved in our design this time, I asked my father why we no longer use solar water heaters in our home and why solar water heaters are not as popular as before.
He told me there are two main reasons. First, because the sun is not strong in winter, the water temperature cannot reach 70 or 80 degrees like summer, but only 30 degrees. But in winter, we want the water to be hotter, so everyone always needs to use electricity to boil the water again, which is very inconvenient and not economical. Second, solar water heaters are placed on the roof, so hot water is also stored on the roof in the solar water heater. Whenever residents living on the lower floors need to use hot water, they need to drain the cold water from the water pipe to get hot water. The waiting time is relatively long, which is especially inconvenient when taking a bath in winter.
Therefore, at least in Hubei Province, China, solar water heating is no longer popular. If we want to call on the people to use solar water heaters, we must first break through some technical problems.
