Pool Solar Panels | Pool Solar Heaters

Solar heaters are also covered with a glass panel to act as a greenhouse, trapping heat within the enclosure. Since heat cannot escape through convection (due to glass), the only way of dissipation is through conduction. Fortunately the rate of conduction is much slower. Therefore most of the heat is retained.

How they work

Cold water runs into a heat exchanger and out comes warm water for your pool. This happens as the black-painted pipes absorb heat from the sunlight and transfer them to the water passing through. The surfaces of the heat collector box are also painted black and certainly helps warm up the air within. This, too, adds to the temperature of the water in the pipes.

The sunlight intensity, rate of water flow and diameter of pipes determine how hot the water will be. Generally, the thinner the pipes, the more efficient the heat transfer. This is because there is more surface area through which heat can be conducted from the pipe into the water.

Advantages

Solar heaters rarely need any maintenance at all. They can also last many decades without significant wear and tear, provided it’s built and installed properly. Most importantly, solar heaters are cleaner and cheaper than gas and electric heaters.

The typically payback period of a pool solar panel is about 1 to 2 years, depending on the sunlight intensity and fuel costs.

Because solar heaters are very simple in design, they make very popular DIY projects. Homemade heaters will obviously cost much lesser than commercially made pool solar heaters. A typical heater may cost within the $4,000 price tag while a do-it-yourself solar heater often cost only a tenth of this price. Therefore the payback period is much shorter.

Installation

Installing a pool solar panel will not be a very tedious task. Most importantly, you should tilt your panels toward the south (if you are staying in the northern hemisphere) so that they can receive more sunlight throughout the year.

Other installation considerations include local building and insurance requirements as well as safety issues. An option is to have a qualified solar thermal contractor to install your solar heating panels for you. This will ensure quality.

With its simplicity, ease of installation and durability, pool solar heaters are getting more popular with consumers. Many DIY enthusiasts are also beginning to put together copper pipes to make their own homemade solar heat collectors to warm up their pool. Such do-it-yourself projects will only get more popular as consumers realize the benefits of using pool solar panels.

Continue Reading:

1. What Are Solar Heaters, How They Work And What They Are Used For
2. 7 Different Ways of Using Solar Energy At Home and In Your Office
3. Heating Up Your Swimming Pool Using Solar Energy

By making use of the wet bulb temperature of water (which is always lower than the ambient temperature), we can cool the air by as much as 18 degree Celsius.

An evaporative cooler is different from an air conditioner. The evaporative air cooler works in the same way as a cool mist humidifier while the air conditioner makes use of vapor-compression cycles to cool the air.

Therefore evaporative coolers are most effective in climates where the air is hot and dry. There are many such regions in the world and in our country. In these places, it is more economical to use evaporative coolers than air conditioners.

(Evaporative coolers use only about 20% of the power consumed by air conditioners.)

In cities like Denver, Paso, Tucson, Albuquerque, Salt Lake City, Fresno, et cetera, evaporative air coolers are very popular.

In humid regions, evaporative air coolers are not as effective. However they can still provide comfort by increasing the air movement inside your room.

How It Works

Let’s take a closer look at how liquid evaporation can cause air temperature to drop. Evaporation requires latent heat. When water turns into vapor, it draws latent heat from the body of water it escapes from.

This process occurs continuously. Therefore water temperature (wet-bulb temperature) is always lower than the ambient (dry-bulb) temperature.

(Note: Latent heat is basically the energy required for water to turn into vapor.)

The rate of evaporation is dependant on the relative humidity in the air. If there is less water in the air, evaporation is faster. (The opposite is also true.) When water evaporates faster, more heat is taken away making the room even cooler.

There are many evaporative cooler designs. The most common ones are direct evaporative cooling, indirect evaporative cooling and two-stage evaporative cooling systems.

In a direct evaporative cooling system, warm dry air circulates within the system to increase the rate of water evaporation. In this process, the total energy in the air remains unchanged. What happens is warm dry air becomes cool moist air. In some regions, this is exactly what people want in summer.

For an indirect evaporative cooling system, a heat exchanger is used. The system generates cooled moist air, which absorbs heat from the environment through a heat exchanger. In this case, the humidity in the air remains the same.

The two-stage evaporative cooler makes use of both direct cooling and indirect cooling techniques. First, the ambient air is cooled as it passes through a heat exchanger (indirect cooling). Then the pre-cooled air passes through a water-soaked medium. This reduces its temperature even more. Through this cooling process, the resultant humidity will not be as high as when only direct evaporative cooling is used.

Building The Widget

Most DIY hobbyists prefer building direct evaporate coolers. This is because the other 2 types of air coolers are more complex. This means more time and materials are needed to make them.

To make a solar evaporative air cooler, you need the following parts and materials:

1. A large plastic box with cover
2. A low-powered submersible pump with plastic tubing
3. An air blower (12-volt DC)
4. Deep-cycle rechargeable 12-volt batteries
5. 12-volt solar panels
6. Basic charge controller
7. Wires
8. Porous sponge
9. Thermometer

A Simple Evaporative Cooler

First, you have to drill many holes at the side of the plastic box and cover it with sponge.

Make this area as large as possible so it is easy for air to enter the box through the damp sponge.

Then attach the submersible pump at the bottom of the container and connect its outlet to a tube that leads to the top of the sponge.

The submersible pump is responsible for keeping the sponge moist so evaporative cooling can happen.

You will also need to cut a hole at the cover of the box for the outlet of the air blower. Make sure it has a tight fit so it is easy to seal the gaps with silicon later.

For the wires, you can use a cable penetrator, which is expensive. Or you can make a small hole, pull through the wires and seal the gaps with lots of silicon.

After this is done, let the silicon dry completely before powering the evaporative cooler. This usually takes about 24 hours.

Meanwhile, let’s work on the solar power system…

Find a place where there is unblocked sunshine that you can install your 12-volt solar panel. Using solar mounts or aluminum brackets, make sure the PV panel is firmly attached before putting the cables into the trunking (if you are using these things).

Then look for a safe place for your battery and charge controller. The charge controller will charge the battery without damaging or over-charging it.

Finally, pull the cables and connect the respective modules together. Always test the output voltage before you connect the wires to your battery to avoid accidental damage.

Using Your Solar Evaporative Cooler

During the day, the solar panel provides energy to charge the battery and power the air blower at the same time. At night when the battery is fully charged, the air blower depends on it for electricity.

Some air blowers emit a lot of noise. When the evaporative cooler has little water in it, noise from the blower may be even more evident. In this case, you may want to put a dampener at the outlet or make sure you buy a quiet air blower.

Do note that the dampener may restrict airflow and this reduces the efficiency of your air cooler.

Using a solar evaporative cooler, you can create a nice environment for yourself without consuming too much electricity from the mains. The battery can last for many years without the need for replacement. Thus you can have many years of free air cooling without expensive utility bills.

Continue Reading:

1. 7 Different Ways of Using Solar Energy At Home and In Your Office
2. Lighting Up Your Yard or Garden Using Solar Energy
3. Making A DIY Solar Powered Reading Lamp

Those of us who have been in the scouts… we were taught that it is safe to drink water that has condensed on a clean surface. When water evaporates, only water molecules escape from the surface, leaving impurities behind.

As water condenses on a cool surface, it becomes purified and is relatively fit for consumption.

This is basically how a solar still works…

To build one, we have to gather these materials:

1. A dark-colored bowl or plate with a large surface area

2. A sheet of strong clear plastic

3. A piece of Perspex that is large enough to cover the container

A dark colored bowl or plate can absorb more solar energy.  This helps to raise the water temperature. When water becomes hotter, more water molecules are able to escape from the surface. This results in more water vapor.

Essentially, we can speed up the rate of water purification as water temperature increases.

First, bend the Perspex along the middle (lengthwise) by a small angle. This will help gather purified water at the center of the Perspex. When it is tilted, water can flow to the side and be collected in a cup.

After the Perspex is bent, use a thick plastic sheet to form a skirting around the Perspex, leaving an opening at the area where water flow out into the cup.

The plastic skirting helps to keep as much water vapor within the solar purifier as possible. It also helps to support the Perspex.

In order to attach the plastic skirting firmly onto the Perspex, you have to use a non-toxic silicon adhesive and wait for it to dry completely.

When properly done, the Perspex should sit slightly above the container but will not touch it. It must also be tilted (slightly) towards where the cup is. This allows water to flow into the cup easily.

To use the solar water purifier, fill up the container with dirty water. Then cover the container with the special Perspex lid. As water evaporates and condenses underneath the Perspex, you can see droplets forming and rolling into the collection cup.

Note:

You can use anything with water content to help you get as much drinkable water as possible. A few of these may include green plants that are not poisonous, damp soil, urine and even snow or sea water.

Continue Reading:

1. Installing Solar Water Heaters
2. Properties Of Solar Energy You Must Know About
3. The Importance Of Heat Transfer In Solar Water Heaters

If you were to install the complete system, it shouldn’t cost you more than $500 to $600. Compared to the entire cost of the swimming pool and the maintenance cost, this is meager.

(A swimming pool costs more than $30,000 in many places)

A swimming pool without no heating facilities is useable for about 4 months in the whole year. With heating, you can use it for 8 months. This is why pool heating is so popular.

Making your own solar pool heater is exciting, because the rewards are so visible. Your family will know that the solar heater warms the swimming pool water. And you made the solar heater…from scratch. Your friends will know it too.

Thus the rewards are more than just functional or financial. It’s ego.

All right, that’s enough for now…let’s move on to the design of the solar heater.

A homemade solar water heater can be built using a PV panel and a solar collector. The PV panel will supply electricity to a submersible pump while the solar collector provides heat to the water flowing through it.

Very simple.

The following is a list of parts you have to buy for this project:

A 12-volt Submersible Pump

1. A 12-volt submersible pump
2. Flexible tubing that fits the submersible pump
3. Black PVC tubing
4. PVC junction (that fits the PVC tubing)
5. A Valve that fits the PVC tubing

With a PV panel running the submersible pump, the amount of water that flows through the solar water heater depends on the intensity of the sun.

In a way, this regulates the water temperature at the output.

When the sun is strong, water is heated faster. But water also gets through the pipes faster. Thus the heating period becomes shorter. The converse is true. When sunlight is weaker, water flow through the pipes slower. Water is now heated longer but with less intensity.

At night, the submersible pump doesn’t work because the PV panel doesn’t supply electricity.

Since the submersible pump is a separate entity from your filter pump, you can run your pool filter for as long or as short as you want without disturbing the pool heating schedule.

(Tip: You can schedule your filter to run at non-peak hours to save on electricity bills.)

When choosing the submersible pump, you must make sure the pump has enough head pressure to get water to where the solar collector is. For example, the solar collector may be located at the roof, which is 20 feet high.

Your pump must have at least 20 feet of head pressure plus an allowance of about 4 to 5 feet more. Thus you’ll want to get a pump with 25-feet head pressure. (Or round the figure up to the nearest spec you can find.)

You’ll want your pump to have a little more pressure than necessary so water flow won’t be weak. With this, you can also have the flexibility to change your solar collector’s position later on if you want to.

When you choose your PV panel, remember to check the power requirement for the submersible pump. Get a rating of at least 10% above what’s required.

A submersible pump costs about $50 and the PV panel costs (at most) $150. The PVC pipes will set you back by another $30.

For the extra money that you spend on a PV panel, you’ll recoup it back (very quickly) because you can keep the energy bills for your filter pump to a minimum.

Finally, you can fix a valve to allow water to bypass the solar collector.

A Bypass Valve For The Solar Collector

There will be times when you feel there’s sufficient heat in the water. All you have to do is open the valve so water flows through the valve instead of the collector.

This happens because water flows in the path of least resistance. Although there will still be water going through the collector, it’s limited.

You can take this further by using a thermistor to create a feedback loop. When your swimming pool’s water is at its desired temperature, the valve is opened so very little heating takes place.

(For this to work, you’ll have to buy a solenoid-driven valve…it costs more.)

In Part Two, we’ll look at how to join the PVC pipes together to make a solar collector.

Continue Reading:

1. Pool Solar Panels
2. How To Make A Solar Powered Water Fountain
3. Heating Up Your Swimming Pool Using Solar Energy