Solar Water Heating

Why use solar water heating?  Water heaters are the third biggest electrical draw in your home amounting to about fourteen percent of your total electrical usage.  Reducing the amount of energy used to heat water will make a noticeable difference in your utility bill each month.

There are a few things you can do before you turn to solar that will reduce your hot water heater usage.  Start by using less hot water and turning down the thermostat on your water heater.  Make sure your heater is insulated and is an efficient model.  Installing low-flow faucets and showerheads is helpful also.

If you are thinking about replacing your hot water heater consider these options.  If you use electricity look into the cost of a heat pump water heater.  They are three to five times more efficient that regular resistance heaters.  Indirect water heaters are another option, they use the homes boiler system to keep the water hot.  Demand water heaters are perfect for some homes and certainly worth considering.  You will not be keeping fifty gallons or so of water hot all day just so you can shower in the evening.  You will however be keeping a pilot light burning nonstop.

Solar Water Panels

Your next step will be installing a solar water heater.  With rebates and tax incentives it is very possible to have the system paid for in a years time.  After that all of your hot water should be free.

Another advantage to using a solar water heater is the reduction of harmful greenhouse gases you are releasing into the air.  You are lowering your carbon footprint, something we all need to consider.  In a twenty year time period it's possible to avoid releasing 50 tons of carbon dioxide emissions.

There are two basic types of solar hot water heaters, flat plate collectors and batch collectors.  Flat plate collectors circulate water through black metal piping while batch collectors are large tanks painted black to absorb the heat of the sun.  Other types of collectors include evacuated tube, transpired and concentrating.  They all use the sun to create hot water which is pumped to your homes hot water heater.

Some of the terms you will hear when shopping for a solar water heating system are:

• Draindown systems are used in cold climates for automatically draining water before it freezes.
• Thermosiphons use a tank mounted above the collectors.  The hot water rises and the cold water drains into the collector.
• Direct systems pump water from a storage tank through the collectors and back to the tank.
• Indirect systems circulate a fluid through a heat exchanger that transfers the heat from the fluid to the water.

Solar Pool Heaters

Swimming pools can use solar energy in a couple of ways.  The suns rays can be used to heat the water and it can also be converted into electricity to operate the filter equipment.  Solar pool water heaters use the sun to heat the pool water as the water is pumped through the collectors.  PV panels can be used to generate the power needed to run the pool pump.

The first step to heating a pool is to get a good quality solar blanket.  A pool cover will reduce water evaporation and heat loss, without a cover it is just about useless trying to heat a pool using solar, gas or electricity.  Good quality pool covers can be found at In The Swim along with a good real system to get them on and off the pool easily.  While most covers will last at least five years they will pay for themselves in the first.

Solar collectors for swimming pools should be about half as large as the surface area of the pool.  In colder climates, or when the pool is to be used year round, you may need to go as much as seventy five percent of the surface area.

Heat can be lost through the pipes running from the collectors back to the pool, so it's best to keep the solar system as close to the pool as possible.  It will use less power to pump the water through the system also.

Your collection panels should be tilted at a degree that would equal your latitude minus 15 degrees.  If your latitude is 40 degrees the panels should be tilted at about 25 degrees.  For year round use it is recommended that you mount the panels on a tilt system so the angle can be adjusted depending on the season.  Tilt systems can be manual or motorized.  A motorized system could even be powered with PV panels.

Small dedicated PV systems are made for operating individual items such as a pool pump.  It could mount on a pole next to your filter system.  Depending on you available sunlight you may or may not need a backup battery.  Most pools will do just fine operating during daylight hours only, and could easily last a couple of days without operating during a spell of bad weather.  A back up battery could be used or the household electric could be the backup power for areas where the sun may be gone for weeks at a time.

We have described a couple of different uses for solar water heating, and several reasons why you might consider getting one or two.