How solar hot water works

1. Imagine you’re an inventor, responsible for developing a system that can heat all the hot water you need in your home. You may have noticed that water takes a long time to heat? That’s because it keeps heat well. We say it has a high specific heat capacity, which is why we use it to transport heat energy in the central heating system. So can we design a simple solar heating system using water alone?
2. In the sunshine, put a plastic bottle filled with cold water in the window, and it will be warmer in a few hours. The trouble is, if you have a house full of people, a bottle of water won’t go too far. How can we boil more hot water? The simplest solution is to fill a large number of bottles with water and put them together on the windowsill.
3. you’ll be more cunning. What if you cut both ends from the top and bottom of the plastic bottle. install pipes at each end and send them to the hot water tank at home to complete the water cycle? Pumps are now installed somewhere in the loop to make the water circulate .
4. What happens is that the sun heats all the hot water in your tank (although it will never be particularly warm. because plastic bottles standing on the windowsill are not so good at collecting heat). But, in theory, you have a working solar heating system here. less than a million miles from where people are installed in their homes. It’s very rough, but it works exactly the same way.

Components of Solar Water Heating System

• collector
  This is the technical name of the large black panel on the roof. Smaller houses (or those in warmer climates) can use much smaller panels for larger houses (or those in colder climates); usually collectors vary in size . Not , collectors work most on roofs that block the sun (there are only a few trees or buildings on the road). speaking, there are two types of collectors called flat plates and vacuum tubes..
• Flat plate collector
  Flats are the simplest collectors: in the most basic collectors, they are only through pipes coated with shallow metal boxes of thick black glass. Glass collects and captures heat (such as greenhouses), and water is absorbed through pipes and transferred to your hot water tank.
• Vacuum tube
  These are more complicated. They look like thicker versions of fluorescent lamps, but more like vacuum bottles. They are totally empty (hence “evacuation”), and they collect and capture heat from sunlight. This flows to the top (or end) of the collection device (sometimes called manifold), through which water or another fluid flows and transfers heat to the hot water tank. Unlike flat-panel collectors, they do not allow heat to escape again, so they are more efficient. However, because of their high technology and complexity, they are sometimes more expensive.
• Hot water box
• If there is no place to store heat, it is meaningless to collect it from the roof. , your home already has a hot water tank (unless you have a so-called gas “combi” boiler, which can make instant hot water) to collect heat from the collector; it’s a “hot water” battery that you can heat at an cheap time (usually at night) for daytime use. If you do not have a hot water tank, you need to install a hot water tank. The more people in your family, the bigger tanks you need. Typical water tanks in family homes may be about 100-500 litres.
• heat exchanger
• Usually, solar panels work by passing heat from the collector to the tank through separate loops and heat exchangers. The heat collected by the panel heats the water (or oil or other fluid) flowing through the pipeline loop into the copper coil in the hot water tank. The heat is then transferred to the hot water tank, and the cooled water (or fluid) is returned to the collector for more heat. The water in the collector has never actually flowed into your tank: the water on your roof has never flowed through the tap!
• Photographs of solar heat collectors use mirrors and water pipes.
• Photo: A different, larger solar water heating system. This uses a parabolic mirror to collect the sun’s energy and concentrate it on a water pipe passing through its center. Water was pumped back to the building in the background (Jefferson County Prison in Gordon, Colorado). Photograph: Warren Gretz, provided by DOE / NREL.
• pump
• Water does not flow between the collector and the tank: you need a small electric pump to circulate it. If you use ordinary electricity to make water flow, the energy consumed by the pump will offset some of the advantages of using solar thermal energy, reduce your income and extend the payback period. , some solar thermal systems use solar power (photovoltaic) pumps, which means they operate on renewable energy. One advantage of this design is that solar pumps are most active on sunny days (when most hot water is being produced) and less active on cold, depressing days (when you may not want solar panels).
• Control system
• If your roof is cold in the middle of winter, the last thing you want is to transfer the cold water to the hot water tank! Thus, there is usually a control system connected to the solar panel, which has a valve that can close the water circuit in cold weather. Typical control systems can consist of pumps, flowmeters, pressure gauges, thermometers (so you can see the heat of the water) and thermostats (shut down the pump if the water becomes too hot).