Design - 1

I had to switch my goal for the reason of a low budget that I have, so I decided to power only one room in my apartment using solar energy. My goal is to have sustained power feeding to this room from the sun with the possibility to use it partially with the grid.

• Before converting to solar energy

Being an automation engineer, and through my 9 working years, I gained a parameter in my personality which is "passion for efficiency and optimization". I make electrical designs and programs for machines and factory processes which are not tolerant to mistakes. These programs must run the equipment efficiently to save power and to output maximum production rate.

That made me always check the power consumption for the home appliances before buying. So I changed most of my 40 Watt incandescent light bulbs to  26 Watt and 35 Watt CFL bulbs. LED bulbs are yet better, and I intend to use them soon.

I also changed my CRT TV to an LCD 23" TV which was adequate for my small living room and for the price at the purchasing time.

Also trading my CRT 17" PC monitor for a LCD 19" one, these actions saved my a few EGP every month.

What I benefit from using energy efficient appliances is that I can use a bigger solar energy system with my available budget aside from saving me a little cash in the previous three years.

Note: when buying electrical appliances, look for the energy consumption grade. A grade is the better.

• Basic load calculations

To decide how much power my living room requires, I must calculate the power drawn by every piece of electrical equipment in that room. I need to know the total power in terms of watt hours to size my solar energy system.

I have the following appliances:

1. 23" LCD TV that draws 50 Watts
2. A dish receiver that draws 25 Watts
3. A fan that draws 137 Watts
4. A CFL lamp that draws 35 Watts
5. A flourescent lamp that draws 38 Watts
6. A computer with power supply which draws 1 A = 1 x 220 V AC = 220 Watts
7. A computer LCD monitor that draws 45 Watts
8. Computer speakers that draws 25 Watts

That will result in a total power of  575 Watts. That is the power drawn by these devices when they are all on for one hour. Therefore I need 575 Watt/Hour (that is different from my previous calculation of 1.6 kWh, and that makes sense because it is about one third of my total power consumption and it's in the living room where me and my family stay most of the time. Aside from that, the fridge, microwave, washing machine, water heater, lighting and air condition consumes the rest)

Every device will be used for a certain hours per day, so let's calculate.

1. 23" LCD TV is on for 6 hours
2. Dish receiver is obviously on for the same 6 hours
3. Fan will be on for 10 hours
4. CFL lamp will be on for 6 hours
5. Flourescent lamp will be discarded
6. Computer+monitor+speakers will be on for 4 hours

The calculation will be: 50x6 + 25x6 + 137x10 + 35x6 + 290x4 = 300 + 150 + 1370 + 210 + 1160 = 3.2 kWh/day. I need a system that can supply that power and recharges itself from the sun for free.

What are the components of solar energy system?

To be continued...