Basics of Solar Water Heater
A Solar water heater consists of 2 main components, a heat collector and an insulated solar tank. There are basically 2 types of heat collectors used. i.e. flat plate collectors and evacuated tube collectors. Emmvee manufactures flat plate collectors which meets the international standards. Our flat plate collector is a single body structure with a unique glass locking. Flat Plate collector has much higher efficiency, longer life, more strength and better look than the normal tube collector. The flat plate collectors perform better in case of hard water flowing through the system.
The Solar tanks are insulated to keep the temperature of hot water maintained for longer durations. A good solar tank can maintain water temperature over night for next day morning usages. A good solar tank is equally important component of the Solar Water Heater System.
How a Solar Water Heater Works?
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By the principal of gravity flow, water from the cold-water tank enters the solar tank at point A and fills it up. The cold water further flows via point B from the solar tank in the bottom header pipe of the absorber, and into the copper tubes at point C, this continuous till the header on absorber top and all the absorber tubes are completely full. As sun shines, its energy, which falls on the absorber fins and tubes, causes the water to heat. Since the heated water is lighter than the colder water it rises through the Top header pipe and flows into the solar tank through point E. The hot water enters the tank from the top and from below the colder water flows into the absorber tubes, gets heated and rises to the top, this cycle gets repeated until the temperature of the water in the solar tank and the absorber equalizes. Now the solar tank is full of hot water. (Note:- Average temperature is 60 degree centigrade at the end of 7-8 hours of bright sunshine.) Further when the hot water is drawn from the solar tank outlet (point F) to the utilities point, cold water enters into the solar tank, this creates a temperature difference between the water in solar tank and absorber triggering the process of flow to start again. There also exists a backup electrical heater (to be used during cloudy days) and the sacrificial anode rod in the solar tank to prevent galvanic corrosion (but not scale formation).
What is a Pressurized Solar water Heater?
A Pressurized Solar Water Heater works on the same principal with one addition of a pressure pump. This is used when the height of the cold water storage tank is at low level or when the usage includes showers or when the number of hot water outlets are more than normal.
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Solar Water Heater Solutions for Multi Storied Buildings
The solar water heating system installed for multi storied buildings uses the same principal, some design changes are made to it to fit to the tough requirements of the usage. Since there are multiple hot water outlets at different levels of the building, it is important to have immediate hot water supply from each outlet and the cold water is no wasted in wait of hot water. An Electronics Control Unit is installed within the hot water plumbing lines. This control unit senses and starts the pump when the water temperature in the outlet pipelines goes below 30° C. The pump then pulls the cold water accumulated and sends it to the solar tank allowing the hot water in the solar tank to replace this cold water.
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What is a Heat Exchanger or Jacketed Type Solar Tank?
This is basically used when the inlet water has chemical components or is hard water. This type of water requires a special type of tank which has 2 concentric tanks ( one inside the other). The water with hardness remains in the inner tank and distilled water remains in the outer tank. The distilled water runs in the heat collector tubes and gets heated up with the same principal, when this hot water reaches back to the outer solar tank it heats up the cold water in the inner tank. Since the inner tank is immersed within the outer tank, the heat gets transferred to the inner tank through the conducted and convection method and the water in the inner tank gets heated up and available for hot water utility.