Know Your Solar Water Heater
- How solar water heater works : In Solar Water Heater there is solar collectors to collect solar energy and an insulated tank to store hot water. Solar collector and storage tank are connected to each other through pipes. In day time, water in solar collectors gets heated from sun rays and this hot water is naturally circulated by thermosyphon principle or is forcely circulated to the storage tank. Hot water then stored in the tank and can be used for various applications, such as bathing , washing etc.
- What are different types of Solar Water Heaters : Two types of Solar Water Heaters are normally used in India one based on flat plate collectors(FPC) and the other based on evacuated tube collectors. Flat plate collector (FPC) based systems are of metallic type- copper collector and have longer life as compared to Evacuated tube collector (ETC) based system, because in ETC system tubes are made of glass which are of fragile in nature. Both these systems are available with and without heat exchanger. They can also work with and without pump. Systems without pump are known as thermosyphon systems and those with pump are known as forced circulation systems.
- Why should I go for a Solar Water Heater / What do I save from it : You can save much more money and will also protect environment from green house gases emissions .if you are using 40 % of your electricity bill for water heating or using one LPG cylinder in one month or using kerosene, diesel etc for heating the water ,this can be greatly saved because sun dosen't charge for its heat.
Which type of solar water heater is suitable for me : ETC based systems are cheaper than FPC based system. If your house is in colder regions and temperature goes bellow zero then ETC system is better because it avoid freezing problem during sub-zero temperature. FPC based systems also perform good with anti-freeze solution at sub zero temperature but their cost increases. In other regions, both ETC and FPC type system perform equally good. Systems working on thermosyphon principle are simple and relatively cost effective.
They are suitable for domestic and small institutional applications, provided water quality is good (hardness of water ) and it doesn't have large chlorine contents. Forced circulation systems are generally preferred in industries or large hotels , hostels etc..
At places where water is hard and have larger chlorine content, if FPC system is used, it must be heat exchanger type, as it will avoid scale deposition in copper tubes of solar collectors. System without heat exchanger can block the flow of water also reduce its heating effect. ETC based systems will not block the flow of water but its performance may go down due to deposition of salt contents on inner surface of glass tubes, which could be cleaned easily once in a year or as required. If you are planning economy system then ETC system will be better choice as it is cheaper than FPC and if cost is not the concern and planning for longer life of system then FPC system will be better choice.
- How do I decide about the size/capacity of the system to be installed : For a house with one bathroom and 3 to 4 members, 100 liter per day capacity system should be sufficient. For more numbers of bathrooms, the capacity should be increased to considere pipeline losses. Generally the capacity is decided as 30 to 35 ltr per person per day for morning bath.
- How do I assure that a good quality system is installed at my house : greentechguru is associated with only MNRE approved brands so don't worry about the quality of system .Also greentechguru has prescreened and prenegotiated the prices of system with qualified installers.
What is the approximate cost of solar water heater : Cost of solar water heater depends on size and type of system installed. For example take a system is 200 liter per day capacity , which means that it can deliver 200 ltr of hot water in a bright sunny day at 60 oC. A 200 lpd capacity system is sufficient for a family of 5-6 members and it may cost Rs.32500 to Rs.35000 for FPC type thermosyphon copper collector system . And yes you can take benefit of group discount for buying solar from greentechguru.
The system cost does not include the cost of cold water tank, & its stand ,hot water pipe line ,cold water pipe line, pump. hardware etc.And this cost depends upon number of bathrooms to be supplied with hot water , type of building .
- Is there any subsidy available from Government : Yes, the Government provides subsidy to the extent of 30 % of the cost of solar water heater decided by MNRE to general category states users. For more on subsidy and loan available please refer to www.mnre.gov.in Can I avail this subsidy & get the system installed at my place. Yes , just you have to fill up the quick quote/enquiry form listed on www.greentechguru.com and then just relax and watch the work taken by the site. All brands with us are MNRE approved. These subsidy you can avail through state nodel agency or through Accredited Channel Partners of MNRE (List available at MNRE website)- .Just you have to pay the net cost after deducting the subsidy.
- What happens on cloudy/rainy day : Do I still get hot water On rainy/cloudy days also, if cloudy sky is for one day or two, you still get warm water as water gets heated due to diffused radiation available in the atmosphere. The system, however, is either connected to an electric gyser/gas gyser in the house or an electrical back- up is provided in the storage tank of the system which is switched on when water is not sufficiently hot. So, you get hot water all the time even on rainy days.
- Are there any maintenance requirements : Domestic solar water heating system do not need significant maintenance requirements. Occasional leakages in the plumbing could be easily repaired by common plumbers. In case quality of water is hard, scale deposition in the collectors may result over the years. This may require de-scaling with acids for which it is best to contact the suppliers/ installers. . If outside exposed surfaces are painted, the paint may have to be redone every 2-3 years to prevent corrosion of the surfaces.