Free water heating possible?

[zap48k]

I have a conventional gas boiler system - with 2 water tanks/feeds (one large, one small - both situated at the same level) in the loft, a storage tank in the bathroom and a boiler in the basement.

Because it gets very hot in the loft in the summer ( via velux window)..

if I was going to somehow channel/concentrate that external heat in my loft towards my water heating system - like say direct the heat towards a pipe going to the water heater or towards the big water tank in the next room in the loft.. can I heat up the water for free or will it cause an issue in the system if I am externally heating up the water?



Thanks
canny scotsman

 

[bernardgreen]

Using heat from a loft to pre-warm water is relatively easy, BUT storing warm water can create a biological hazard in that bacteria such as legionella can multiply in warm water.

The bacteria multiply where temperatures are between 20-45°C and nutrients are available. The bacteria are dormant below 20°C and do not survive above 60°C. Legionnaires' disease is a potentially fatal type of pneumonia, contracted by inhaling airborne water droplets containing viable Legionella bacteria.

Not sure where the nutrients would come from in a closed (but vented) storage tank but the industry seem very concerned about Legionella in stored warm water.

 

[zap48k]

Oops, very good point

I would find it very difficult to get the heat down to the closed storage tank in the bathroom and so I originally thought I could perhaps just heat the exposed water tanks in the loft (or the pipes leading from them), perhaps not then!