All You Need to Know about Solar Water Heaters

All You Need to Know about Solar Water Heaters
August 9, 2012 Lorelie

Are you going to buy a new water heater unit for your home?  Maybe you would be interested in getting a water heater that is not only efficient and reliable in heating water, but also it helps preserve Mother Nature as well.  Solar water heaters and residential solar water heating systems are actually a popular choice for many people nowadays, especially those who are more conscious in using up energy without causing harmful consequences to the environment.  Most people who have considered getting solar water heaters agree that their units are more reliable, competitive, efficient, and it uses free solar energy that is renewable, unlike other types of water heaters available in the market.

The cost benefits for using green-tech solar water heaters are much better nowadays – government tax credits and utility rebates are available, and the value of your home becomes more significant because it is geared towards environment protection, renewable energy utilization and you are energy independent.

If in case you have a new house or you are in the process of doing home improvements and would like to incorporate green technology to your home, you can acquire solar-powered water heaters.  Due to its flexibility and is easy to install, solar water heaters can be added to your pre-existing heating system and combine it with a new system.

Solar water heating systems and solar water heaters can be used in just about any climate, especially if you live in southern regions.  Solar water heating can actually be a cost-competitive method as opposed to heating water with the use of natural gas, propane, electricity and oil, but you also have to consider that it also depends on your location and the prices of fuel.  Keep in mind that solar energy is renewable energy that is clean, green, pollution free and is absolutely free.  Solar water heaters work best when there is always lots of sunshine available.

Basic Parts of a Solar Water Heater

Below are typically the basic parts of a solar water heater unit:

  • Solar panels or collectors
  • Storage tank except batch systems
  • Pump
  • Support structure
  • Thermal expansion tank
  • Freeze protection
  • Controller
  • Other parts for safety measures

How a Solar Water Heater Works

Solar water heater systems are considered to be one of the most reliable, efficient, simple and cost-effective methods of harnessing the sun’s energy in order to provide hot water to your home.

Solar water heaters, just like any other solar-powered device, use panels or flat-plate collectors that are either mounted on the roof or installed on a freestanding frame.  The main function of the solar panels or collectors is to capture the heat of the sun and transfer the energy further.  As the water circulates (either naturally or forced by pumps), it transfers the collected energy to a storage tank, either directly or indirectly.  These storage tanks are typically located either on the roof or in the garage.

There are basically two types of solar water heater systems, the open-loop and the closed-loop.

When you are in a cold climate, the water heating system has to be drained because the water can potentially freeze.  The closed-loop or indirect solar water heating system utilizes an antifreeze solution.  This type of system consists of a piped loop of water or antifreeze that is separated from the hot water supply by a heat exchanger.

If you live in an environment that has a colder climate, then you will have to use the drain-back solar water heater system.  The water which is in the collector and pipes drains into an insulated tank whenever the pump shuts off.  This is considered to be a safe way of removing water when not collecting solar heat and to avoid freezing.

If you live in an environment that has a warmer climate, then you will have to use the direct solar water heating system.  The potable water readily available from your home plumbing system circulates directly through the solar collector and into the storage tank.

If active solar systems are utilized, hot water is moved from the collector to the storage tank with the use of pumps and controls.  If passive solar systems are utilized, or usually called thermosiphon, there are no pumps and other electrical components used in order to move the hot water from the collector to the storage tank.

Tip #1:  If you want your solar water heater unit to be energy efficient, ensure that the storage tank is of the right size.  It should match the solar panels area and the needs of the family for hot water.

Tip #2:  If you want your solar water heater unit to be energy efficient, the collector pipes and the storage tank must be well insulated.

Take note that there are several solar heating systems that have a back-up heater, so you can always have hot water available even when there is not enough sunshine available.

Types of Solar Water Heating Systems

There are actually many types of solar water heating systems, and they are all considered to be very popular because they are reliable, simple, efficient and long lasting.

Direct System – Direct solar water heating system is when water is heated directly inside the solar panel or collector from the heat of the sun.

Indirect System – Indirect solar water heating system is when water inside the tank is heated by the solar fluid that circulates through the heat exchanger.

Active System – Active solar water heating system is when cold and heated water moves through the solar heating systems with the use of an electrically-powered pump.

Passive System – Passive solar water heating system is when the solar water heater does not use external energy for its parts (no moving parts). This means that cold and hot water circulates by using the principle of natural law.

Open-loop System – All open-loop systems are direct and active.  Water circulates directly through the solar panels or collectors with the use of the circulating pump.

Closed-loop System – Closed-loop systems are indirect as water is heated indirectly – first the sun heats up the solar fluid that circulates through the heat exchanger where it transfers the heat to domestic water.

Thermosiphon System – Thermosiphon solar water heating systems use the natural law where the hot water naturally rises up, so the solar water heater tank is situated above the collector.  They can be divided on indirect and direct solar water heating, or they can get heat from the solar fluid or get heat by being exposed directly to the sun.

Integral Collector Storage (ICS) System or Batch System – ICS or batch solar water heating systems do not need pumps as they are passive.  They do not have storage tanks as the water is heated directly in the collector.

Drainback System – Drainback systems are considered as active, indirect and closed-loop solar heating systems.  They can actually be used for both water and home space heating, and can be used anywhere except in places where it is extremely cold.  Its main advantage is that it can drain all the fluid out of the collector when the system is turned off, meaning that they require continuous drop between the solar collector and solar storage tank.

Advantages of Solar Water Heaters

  • Solar water heaters use free, renewable solar energy.
  • Because they use free solar energy from the sun, solar water heating systems can supply up to 50% of the energy that is needed for your home which can greatly minimize your heating costs.  Of course, this depends on the climate in your area and the hot water demand in your home.
  • Some solar water heater units do not need electricity to operate.
  • Easy to maintain.
  • Can be utilized to directly heat the swimming pool.
  • Reliable and a cost-effective method of heating water.
  • There are government incentives when you use green tech energy.
  • There is increased energy independence.
  • You are helping the environment to be a cleaner one by reducing greenhouse gases.

Disadvantages of Solar Water Heaters

  • High installation cost.
  • Higher start-up cost as compared to electrical or gas water heaters.
  • If the temperature is cold, the solar energy use drops.
  • Because of the small pipe size of the collectors, the solar water heater units are prone to mineral buildup.

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