Solar Water Heater- Device Utilizing Solar Energy

Solar water heating helps in the process of conversion of sunlight into renewable energy which allows water heating by using solar thermal collectors. This is installed at the terrace where sunlight is available. It heats water and stores in an insulated storage tank.

Working principle of Solar Water Heater

Components

Three components that help in solar water heating are:

  1. Solar Collector
  2. Cold water tank with required insulated hot water pipelines and accessories.
  3. Insulated storage tank for hot water and

                         Solar Water Heater

Working

  1. When sunlight falls on the solar collector, due to solar energy the water gets heated up in the glass tubes or metal tubes.
  2. The water heated up which is less dense will rise in various tubes and reaches the top of the insulated hot water storage tank.
  3. The cold water will descend in the tank to the tubes and gets heated, thereby continuing the process as a cycle.
  4. The hot water moves upwards into the tank because of density difference. The insulated tank ensures that the hot water remains hot for a long time.

Types of Solar Water Heating Systems

1. Passive

Passive heaters use heat pipes to circulate water or fluid through the system. There are two types of passive systems:

  1. Thermosiphon

Water tank and the solar collector are separated in this system. Cold water moves through the solar collector tubes and by the process of convection, hot water moves to the storage tank. The water from the storage tank is then given to the house pipes.

  1. Batch

Water tanks are placed in the solar collectors and no tubes are present in this system.

  1. Active

Active heaters use pumps to pass water and/or heat fluid in the system. There are three types of active solar water heaters:

  1. Direct

Water moves through solar collectors and flows into the storage tank by electrical pumps.

  1. Indirect

Solar collectors heat a fluid like antifreeze instead of a liquid. 

  1. Drainback

This system uses distilled water and it stores them in a tank.

Solar Collectors

The main function of solar collectors is to absorb the solar energy and convert it into heat energy.  Some of the different solar collectors are:

  1. Flat-plate collectors
  2. Evacuated-tube collectors

Flat Plate Solar Collectors

                                       Flat Panel Solar Collector

This is the most common type of solar collector used.  It consists of a

  • Transparent front cover,
  • Absorber and
  • Housing.

The absorber is placed inside the collector housing. The main function of the absorber is to convert solar energy to heat energy. This heat is then transferred to the water in the tubes of the absorber. Usually absorber is made of aluminum, copper and steel.  While the collector housing is made of plastic, wood or metal. This housing is insulated at side’s inorder to reduce heat loss. A glass sheet covers the solar collector as it faces the sun, and this prevents losses.

Evacuated-tube collectors

                                                                Evacuated Solar Collector

An evacuated-tube collector consists of a closed glass tube containing a metal absorber sheet with a heat pipe in the middle and methanol acting as a temperature-sensitive medium.  Solar energy will heat up and vaporize the fluid present in the heat pipe. Vapor will flow to the condenser and heat exchanger at the end of the pipe. Condensed fluid will then move to the bottom of the heat pipe and the solar energy will heat up the water again. Higher energy gain is obtained in these solar collectors, but the price is higher than flat plate solar collectors.

Homemade Solar Water Heaters

Today, building a solar water heater at home is simple and easy.  You guys just need some basic parts for the system, they are:

  1. Glass Sheet
  2. Black Paint
  3. Electric Water Heater  Tank
  4. Wooden Box
  5. Pipes
  6. Insulation Material
  7. Mountings

Now follow the simple steps below to build a solar water heater, a homemade one.

Step1:  First take the water tank and paint it black, so that more solar energy is absorbed by it.

Step2:  Fix glass over the top of the box.

Step3:  Cut holes through the box so that inflow and outflow pipes can pass through.

Step4:  Place the water tank inside the tank.

Step 5: Allow the incoming cold water to the end of the tank and allow the hot water to move to the homes water tank.

Step6: Place the solar water heater system mounted in a desired location.

These simple steps help to make your homemade Solar Water Heater.

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