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Off The Grid

I'm going to live off-grid. Read my blog and learn how to do it yourself!

5 ways to harness solar thermal energy

Today I wanted to show you in brief 5 good ways to use solar energy to produce useful heat. Most people probably at this moment think about solar thermal collectors for domestic hot water, but there are many other possibilities.

Of course I will write about solar collectors, though it’s not a device I suggest to use or purchase.

I hope this article will be an inspiration for further research and reading for you.

1. Solar thermal collectors for hot water

This is the traditional way many people in modern Europe use solar energy. The solar irradiation heat the fluid circulating in flat plate or evacuated tube collectors. If frost is not a concern, this fluid is simply domestic water, while in colder climates some solution of glycol has to be used. In the latter case an additional heat exchanger must be used. (more…)

My two new solar panels

Two weeks ago I go a delivery from a shop modernHome.pl, that contained two new 30 W solar panels. This weekend I finally had some free time to make some tests and prepare some photos to show here.

At this moment my solar system has 150 Wp and consists of 5 solar panels. I have one 10 Wp flexible solar panel, two 40 Wp laminated glass panels and those two Wp monocrystal panels.

DSCF1726

Me and one of my two new solar panels.

The solar panels are made of 36 monocrystal solar cells connected in series. In standard conditions (1,000 W/m², AM 1.5, 25°C) they give 30 W output each. Since I don’t have a wattmeter that would be able to measure the power of such device (I own a wattmeter that’s plugged into wall socket and measures the amount of energy used by household devices, but that won’t work here), so the only thing I could measure is the open circuit voltage (Voc). (more…)

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  • PV systems energy profitability

    Those of you who know me better, know also, that I am a moderate fan of photovoltaic energy systems (solar panels). The first solar panel I bought (flexible 10 W) 5 years ago, and since that time, my PV system has grown to 150 Wp. Lately I aquired two 30 Wp panels, which I want to review here as soon as possible.

    I calculated some time ago that photovoltaics is not a viable solution from the economic point of view. But is it worth to spend energy od manufacturing PV panels and use them somewhere else to produce solar power? Isn’t it just a way to store electrical energy? What is the EROEI of such an investment?

    I wouldn’t worry about that if I didn’t hear an interview with Steve Harris of USH2.com, who is an expert in the energy field. He said that PV systems are one of the worst investments you can make, because you simply transfer energy in the form of silicon crystals from Japan to USA or Europe.

    (more…)

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  • Pros and cons of flexible solar panels

    I bought my first solar panel (not taking into account the ones I had in my calculator or watch) in 2006 r., and it was a flexible 10 Wp (PowerFlex 10 from ICPSolar). With the charge controller I had and a typical lead-acid car battery, it was my first solar system I used in my RV (camper van).

    At the moment I have in my RV two standard solar panels (laminated in glass) and lead-acid deep cycle batteries (as far as I remember, AGM – absorber glass mat – type). I used both the standard solar panels and the flexible ones, so I have an idea on what are the pros and cons of two types of solar panels. (more…)

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  • A week off the grid on a campsite

    Last week I returned home from a short summer holiday which I spent in my Vanagon Camper (RV) in Łeba, a town on the Baltic Sea coast. As I own two solar panels (40 Wp each) and two gel batteries, I decided not to pay for the electrical connection and use my own power.

    The prices for using the grid on the campsites in Poland are extreme. From your point of view probably it’s as cheap as everything here (10-15 PLN per day = $3-5 / day = 2.5-3.7€/day), but if you compare that price to the price of energy (0.5 PLN/kWh) it’s not worth it.

    On the other hand, since I paid for the solar panels only about 900 PLN, this investment pays for itself after 60-90 days on the campsite, which is in my case equivalent to roughly 4-6 years of camping holidays. Of course that doesn’t take into account the batteries, charge controller and wiring that is not free either. (more…)

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