Thermal panels Portugal Algarve - Sun heat energy project

Thermal solar panels Portugal Algarve - Thermal energy storage system project for heating water for domestic use. Sun energy in the Algarve is an excellent way to heat your pool, jacuzzi or household water with thermal panels of high quality.

Thermal panels Portugal Algarve - Sun heat energy project

How do thermal collectors work:

  • The sunlight falls on the double-walled glass tube.
  • The light passes through a first glass layer that is translucent.
  • Therefore, the second layer of glass is absorbing the light. A a black heat-absorbing coating is covering this layer.
  • Heat transfer can no longer escape through the insulating vacuum layer between the two glass walls (thermo-principle).
  • Meanwhile, the temperature is released inside the Heat Pipe (copper tube) to alcohol. Alcohol is already boiling at 25 ° C (the warmer, the higher the pressure, the higher the boiling point).
  • Evaporated alcohol rises and when it enters the top of the inclined Heat Pipe, it gives off its heat to a copper reservoir, condenses and drips down, allowing the cycle to start again.
  • Heat is going upwards and gives off its heat to the copper reservoir. The reservoir can reach a temperature of 250 ° C.
  • The copper reservoir gives off its heat to the water or an antifreeze (glycol) but does not come into contact with it.
  • The heated glycol is pumped through insulated pipes along the top of the sun collector to the buffer vessels.
  • Glycol transfers heat to tap water and/or central heating water via a spiral in a buffer vessel.

Thermal energy storage system advantages:

The choice for Evacuated tube heating is because it has the highest efficiency. Evacuated tube panels are the most expensive but most efficient type for a thermal hot water system. They have a conversion rate of 90%, so they can produce more heat than other types of solar thermal energy panels like flat plate collectors.

If you look at the picture on the head of this article, you see a installation off 15 panels. Each board has 25 tubes. Five heat modules are in serial connection, the three rows are parallel.

The control unit, DeltaSol master brain.

A Solar controller DeltaSol computer controls the whole system. Inside there is a pump for the water flow in the heating tubes. This computer monitors the temperature of the panels.

If the temperature is 10 degrees higher than required, the pump will start to run and the hot water will start to flow from the boards to a heatsink changer. Of course there are all kinds of variables to set.

This control computer also checks which source the heated water is going to. To control the sources is done by three-way valves. Within this energy project there are two sources that need to be heated. And one source for dumping the generated energy what can not be used anymore in the thirst two sources.

First the boiler for domestic use. As second the jaccuzi and finally the pool. You can set the priority of the sources in the resol solar control computer without changing the hardware.

Thermal panels Portugal Algarve - Sun heat energy project

The solar boiler:

The water tank solar boiler is from the German firm Reflex. The type is Reflex Storatherm Aqua. A 500-litre tank with a heat exchanger, to transfer the heat of the Evacuated tube boards into the storage tank.

Above all, reflex indirectly fired Storatherm Aqua water heaters with A-label. Thanks to unique patented rECOflex rigid foam insulation, the boilers are very economical. They heat up quickly and very evenly and have an attractive design.

There is a connection for electrical heating in the front of the boiler. Not shown on this image. For the days when the sun does not shine enough in the algarve. The heater can also keep the boiler at the right temperature during the night.

In this energy project, the boiler is in the technical area from the pool installed.

The red and the blue barrels are there to absorb pressure differences. The red for the thermal collectors system, and the blue for the boiler.

Thermal panels Portugal Algarve - Sun heat energy project

I took this picture at the time that I was doing a lime inspection. The grey PVC tube on the front ( picture right ) is temporarily replacing the electric heater.

According to the set heating algorithm, the boiler is at a temperature at 62 degrees. By switching an electric valve, the hot water goes to a heat exchanger for the jacuzzi.

The same principle also applies here. With a preset temperature of 36 degrees, the resol control computer starts to heat the pool. If during the heating of the swimming pool or the jacuzzi it turns out that the boiler temperature is lower than 58 degrees, the cycle starts over again. And start to get the domestic water supply back on temperature.

The exchangers for the pool and the jacuzzi are very different from the boiler.

The top img is a pipe changer, the left img is a plate changer. Both are about 90 kW. I had to choose a different type of exchanger for the swimming pool. The pool has a volume of 120m3.

But, it is important to maintain a good flow for the water quality. A pipe heat exchanger gives this possibility.  The jacuzzi has a volume of 9m3.

In conclusion, in terms of efficiency, the plate exchanger has the highest transfer coefficient. But also the lowest flow speed.

Solar thermal systems Portugal Algarve - Sun heat energy project

This whole project has been realised by https://www.solar2power.pt/. This company has delivered and installed all necessary equipment. My job as energy project manager was fine tuning according to customer requirements.

Read more about other projects.

More about other solar thermal technologies: SUN_Thermal_Technologies.

To sum up, all the advantage of thermal heating, the conclusion is that it produces a lot of work to install and maintain the installation. From experience, I can say that water heating with photovoltaic solar PV panels is more efficient. And surely more controllable.

In conclusion i can say that, If you are planning thermal energy storage system, to do somthing with the free sun energy. First, explore other energy systems and products, like a solar system with My-PV, to lower the energy bill.