Masdar Interview part 1: “I think it is quite okay”
Filed under: Solar Energy News
ClimateGate Part Deux is a Snoozefest
A second round of hacked emails from the same batch of the first ‘ClimateGate’ correspondence is loosed upon the world. And nobody cares.
How To Make A Simple Homemade Solar Pool Water Heater – Part One: Design and Construction
You can buy a solar water heater to warm up your swimming pool or hot tub for a few hundred dollars. They are not expensive. For example, each 4 by 20 feet panel costs around $ 250.
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:
- Pool Solar Panels
- Heating Up Your Swimming Pool Using Solar Energy
- How To Make A Simple Homemade Solar Pool Water Heater – Part Two: Building The Solar Collector
How To Determine The Payback For Your Solar Panel Investment (Part 2 of 3)
Calculate Your Payback Period
The payback for your solar panel investment is the amount of time needed (in years) for your investment to pay for itself (break-even).
A simple calculation gives you a clear picture:
You should divide the total upfront cost by your monthly estimated savings. This gives you the payback period in months.
Dividing this by 12 gives you the payback period in years.
To figure out your monthly savings, you can follow these steps:
1. Determine your average monthly energy usage by referring to your power bills
2. Estimate how much energy (in percentage) you will replace with your solar panels
3. You’ll find out your monthly savings by multiplying the numbers you got from step 1 and step 2 above
For example, you found out that your monthly energy bills cost you $ 200. If your solar panels are designed to supply about 60% of your energy usage, your monthly savings will be: $ 200 x 60% = $ 120
Thus if your solar equipment and installation cost you $ 14,000, your payback period is $ 14,000 / $ 120 / 12 = 9.7 years.
For all the gains you’ll receive from your investment, you have to take a look at what your risks are.
I’ve listed the major ones here so you can consider if owning solar panels are indeed worthwhile:
Risk #1: Efficiency declines over time
Solar energy systems (like everything else) decline in efficiency over time. After a period of 10 years, you can expect a 15% drop in efficiency.
Different systems deteriorate at different rates though. The expected efficiency deterioration is subtly implied in the manufacturer’s warranty condition.
Risk #2: Lifespan of solar panels
Everything has its lifespan. For solar panels, warranties usually cover your equipment for 20 to 25 years. You system is insured against defects and drastic drop in performance during this period. However solar panels can last much longer, sometimes beyond 30 years.
There will come a time (that is not definite) when your PV panels cannot generate the amount of electricity you require and it’s ready to be discarded.
Risk #3: More efficient technologies
Some years in the future, technology will improve. Occasionally engineers discover breakthroughs that make solar panels efficiency improve by leaps and bounds. In this case, unless you have lots of cash to throw away, you are bound to the old photovoltaic technology.
In Part 3 of this series, we’ll take a look at how solar panels can improve your property’s value. This helps in the payback period, definitely.
Part 1 of this series can be found here:
http://www.diysolarpanelsworld.com/how-to-determine-the-payback-for-your-solar-panel-investment-part-1-of-3
Continue Reading:
- Challenges and Difficulties In Using Solar Panels And How To Overcome Them
- Creating An Energy Efficient House – A Primer On Why You Should Do It and How
- Do-It-Yourself (DIY) Projects That Can Complement Solar Panels
Leave a Book on a Bench: Be Part of the Book Swap
Photo: B. Alter
At a time when libraries are being closed down and the very future of the book is being questioned, let’s give a cheer for the book swap. Organized by the UK newspaper, the Guardian, think of it as a generous act of recycling.
…Read the full story on TreeHugger
