Choosing a New Water Heater – Solar Water Heaters

Choosing a New Water Heater – Solar Water Heaters
December 29, 2011 Lorelie

If you will be replacing your old water heater soon, you may want to consider new options for your next water heater.  This may involve choosing a new type of water heating system that is totally different from your old unit.  It is important that you become open to this as there are water heating systems that are more economical to use as compared to the more traditional storage water heaters.  Then again, you must also weigh the advantages and disadvantages so you can be sure that you are getting the right unit.  One of the things you need to look at when buying a new water heater would be energy efficiency.  If a water heating unit can provide your whole household the hot water heater it needs but requires less to run, then that would be the perfect water heating system for you.  However, when getting such a system, you need to be ready to pay its premium.  Then again, the added price you pay will be offset in the long run by the savings you get from your utility bills.

Storage water heaters, tankless water heaters, solar water heaters, heat pumps and indirect water heaters are the 5 types of water heating systems.  Each type of system has its own advantage and disadvantage.  This makes it essential to know which one is best for your water heating needs.

Solar Water Heaters

Solar water heaters can be considered as the most cost-effective way you can generate heated water for your home use.  They can be used regardless of the climate in your area as long as they have a clear line to sun’s rays.  The best part about solar water heaters is that the energy they use is sunlight which is free.

A solar water heating system would include solar connectors and a storage tank.  Basically, there are 2 types of solar water heaters – active and passive.  Active units have circulating pumps and controls while passive units don’t.

There are basically 2 types of Active SystemsDirect and Indirect circulation systems.

  • Direct Circulation Systems – these active systems have pumps that circulate cold water from the home to the solar collectors.  This type is highly effective for warm regions that do not encounter freezing temperatures.
  • Indirect Circulation Systems – these are active systems that circulate non-freezing liquid through the collectors and channel the heat to a water storage tank via a heat exchanger.  This systems are highly effective on cold regions prone to freezing temperatures.

Passive systems are usually less expensive than active systems and their main drawback is that they are not as efficient.  Nevertheless, these systems are more robust and reliable.  There are basically 2 types of Passive SystemsIntegral Collector-storage Passive System and Thermosyphon System.

  • Integral Collector-storage Passive System these are systems that are ideal for areas with temperatures that seldom fall below freezing.  They are useful for households with daytime and nighttime demands for heated water.
  • Thermosyphon Systems this system has the solar collector pipe installed under the storage tank.  This system uses thermo and hydrodynamic physics as the warm water will rise up the tank.  These systems are very reliable.  However, when installing them, contractors need to pay attention to the roof design and its integrity as the storage tank can be quite heavy.  These systems cost more than integral collector-storage passive solar water heating systems.

Almost all solar water heaters though require a storage tank which will be used to store the already heated water.  This makes it important to have a storage tank that is well insulated to prevent standby heat loss.  On some setup, a two-tank system, the solar water is used to preheat water before it enters the more traditional storage tank water heater.  This allows savings as the latter not longer needs to heat the water from a cold stage.  Another setup, a one-tank system, the solar water heater is used to heat water and store it in its tank so that when heated water is on demand, the tankless water heater won’t have a hard time heating the water further.

There are three types of solar connectors used for solar water heaters – flat-plate solar collectors, integral collectors-storage systems, and evacuated-tube solar collectors.

  • Flat-plate Solar Collectors – Glazed flat-plate collectors have dark absorber plates underneath a glass or polymer cover.  Unglazed flat-plate collectors have a much darker absorber plate and are made of metal or polymer.  This type of flat-plate collector does not have any enclosure and is the type typically used for pool heating.
  • Integral Collector-storage Systems (ICS) – this type of solar collector feature one or more black tubes inside an insulated glazed box.  Cold water will first pass through the ICS which then preheats the water.  After passing through the ICS, the preheated water will then continue to go to the traditional storage water heater where the water will be heated to desired preset temperature.  ICS-type solar water heaters are recommended to be installed on mild-freeze temperatures only as the external pipes may freeze once the temperature drops substantially.
  • Evacuated-tube Solar Collectors – this type of solar collector has an array of transparent glass tube arranged parallel to each other.  Every tube has an outer glass tube along with a metal absorber tube connected to a fin.  The coating on the fin absorbs solar energy but holds back radiative heat loss.  These solar collectors are mostly used for commercial applications.

Installing a solar water heating system will actually depend on multiple factors.  Some of these factors would include solar resource, climate, safety issues as well as local building codes.  This makes it important to have a qualified contractor to install the system for you.  Once the installation has been done and the system is running smoothly, you will need to have it maintained by a solar contractor at least every 3 to 5 years to keep it running that way.  For active systems, it is important to discuss the maintenance requirement with your unit provider.  Passive systems on the other hand do not really require that much maintenance.

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