# solar heating



## raprog (Nov 23, 2014)

Hello again, can someone tell me how the Solar Heating works and costs, and is it efficient. Thanks Roger


----------



## David_&_Letitia (Jul 8, 2012)

We have our domestic water heated by solar panels which, as long as we have had sunshine (most days of the year!) is very efficient.

Even on the morning after a really sunny day, we find the water still hot enough for a shower, but I believe that many expats here change their bathing habits to afternoon/evening when you can guarantee that the water is as hot as you want it to be. We will no doubt follow this pattern once we break the lifetime habit of morning showers!


----------



## David_&_Letitia (Jul 8, 2012)

raprog said:


> Hello again, can someone tell me how the Solar Heating works and costs, and is it efficient. Thanks Roger


I forgot to answer your specific question! As a tenant, solar power is free for us. From other posts I have seen, it is possible during the cold winters in high altitudes for the water in the solar panel to freeze (I suspect a rare occurrence) in which case replacement panels are necessary for owners/landlords.


----------



## expatme (Dec 4, 2013)

raprog said:


> Hello again, can someone tell me how the Solar Heating works and costs, and is it efficient. Thanks Roger


The way it works; The solar panel is a aluminium box. The inside is painted black. Copper pipes are laid and fixed into the box. There is a feed in and a feed out (water supply). The whole of the face of the box is sealed with a glass cover. This is the solar panel. The heat from the sun transmitted through the glass onto the black inside onto the copper pipes heats the water to a very high temperature. The solar panels are usualy placed to face the sun at an angel of approx 45 degrees. The top pipe out of the panel leads to a lagged encase heat retaining hot water tank. The bottom inlet pipe is fed from a cold water cistern. The copper pipes are also painted black.

Hope that you can understand.


----------



## raprog (Nov 23, 2014)

Hello Expatme, great explanation thankyou, so would it run radiators for heat?
Roger & Sandra


----------



## Veronica (Apr 5, 2008)

No these panels are only used for hot water. They don't produce enough for heating the home. For that you need photovoltaics which are very expensive to install.


----------



## expatme (Dec 4, 2013)

raprog said:


> Hello Expatme, great explanation thankyou, so would it run radiators for heat?
> Roger & Sandra



Unfortunately NO. As you use the hot water there is cold water entering the pipes all the time and so eventually it goes cold-not nice in the winter or on a bout of several overcast cloudy days. Also with radiators a pump needs to be on at all times to circulate the hot water.


----------



## raprog (Nov 23, 2014)

Hello, shame, sounds very technical Veronica. one can but hope!!

Roger


----------



## Veronica (Apr 5, 2008)

Actually photovoltaic panels produce electricity and if you have enough of them you can be totally self sufficient in electric and would use electric heating.
However no landlord would go to the expense of installing the very expensive system so as you are renting your chances of having these are zero I am afraid.


----------



## PeteandSylv (Sep 24, 2008)

Expatme has described quite clearly the solar panel heating system for an direct system which I believe relates to older systems. The indirect system has the hot water fed from the solar panel into a heat exchanging coil within the hot water tank. There it releases its heat into the surrounding colder water. The then cooler water within the coil is returned to the solar panel. The advantage of this system is that only a small amount of water circulates in the heating circuit minimising corrosion. This is an exact parallel with central heating systems in the UK, the hot water is heated by a coil in the hot tank and not the water that reaches your body.

I have also heard that there are solar panels not utilising copper or other metal pipes but a form of plastic pipe which is capable of expanding with water when it freezes.

As far as panel freezing is concerned this is a problem in many places, ask the residents of Polemi. I was just discussing a friend's replacement panels with him the other day. This winter was rather expensive for him.

Pete


----------



## Baywatch (Mar 30, 2014)

PeteandSylv said:


> Expatme has described quite clearly the solar panel heating system for an direct system which I believe relates to older systems. The indirect system has the hot water fed from the solar panel into a heat exchanging coil within the hot water tank. There it releases its heat into the surrounding colder water. The then cooler water within the coil is returned to the solar panel. The advantage of this system is that only a small amount of water circulates in the heating circuit minimising corrosion. This is an exact parallel with central heating systems in the UK, the hot water is heated by a coil in the hot tank and not the water that reaches your body.
> 
> I have also heard that there are solar panels not utilising copper or other metal pipes but a form of plastic pipe which is capable of expanding with water when it freezes.
> 
> ...


There is a lot of solutions for the freezing problem in other countries. There are simple sytems that empty the syytem when it is danger of freezing, but it seems not used here


----------



## PeteandSylv (Sep 24, 2008)

Baywatch said:


> There is a lot of solutions for the freezing problem in other countries. There are simple sytems that empty the syytem when it is danger of freezing, but it seems not used here


A bit drastic and prevents getting hot water!

New indirect systems here are filled with anti-freeze solution of some form rather than plain water.

Pete


----------



## Baywatch (Mar 30, 2014)

PeteandSylv said:


> A bit drastic and prevents getting hot water!
> 
> New indirect systems here are filled with anti-freeze solution of some form rather than plain water.
> 
> Pete


Why it prevent from getting hot water?. As soon as the panel temperature the valve open again and fill the system.


----------



## PeteandSylv (Sep 24, 2008)

Baywatch said:


> Why it prevent from getting hot water?. As soon as the panel temperature the valve open again and fill the system.


and if you have a prolonged cold spell?

Pete


----------



## Baywatch (Mar 30, 2014)

PeteandSylv said:


> and if you have a prolonged cold spell?
> 
> Pete


A drainback system is an indirect active system where the HTF (almost always pure water) circulates through the collector, being driven by a pump. The collector piping is not pressurized and includes an open drainback reservoir that is contained in conditioned or semi-conditioned space. If the pump is switched off, the HTF drains into the drainback reservoir and none remains in the collector. Since the system relies upon being able to drain properly, all piping above the drainback tank, including the collectors, must slope downward in the direction of the drainback tank. Installed properly, the collector cannot be damaged by freezing or overheating.[20] Drainback systems require no maintenance other than the replacement of failed system components


----------

