PV Gap

Terrance Said:

Why is neither pure water or pure ethylene glycol used in a solar heating system?

We Answered:

Solar thermal systems use a blend of a glycol and water to take advantage of favorable features. Glycol is included because it lowers the freezing temperature of the blend, to prevent formation of ice. Water is included because of its excellent thermal conductivity and specific heat capacity, highest among just about all fluids.

The glycol is more often propylene glycol than ethylene glycol. It is surprising, but true, what the difference of two hydrogens and a carbon make in terms of toxicity...but propolyne glycol is relatively non-toxic, unlike its ethylene glycol counterpart. So, if the fluid blend is to interact with domestic use water on opposite streams of the heat exchanger, it is best to choose propolyene glycol in order not to make it a poison. If it isn't, and only will be used for heating, then ethylene glycol can be used.

Alicia Said:

What are solar heating systems are classified as?

We Answered:

b. active and passive

Michele Said:

which of the following is not true regarding active solar heating systems?

We Answered:

b is incorrect.

Diana Said:

what are three means of distributing heat are used by purely passive solar heating systems?

We Answered:

It's amazing! You might try this places: http://popfaves.com/308283/solar-heating

Jesus Said:

How can I install a solar heating system on my new pool?

We Answered:

I installed my own solar system as soon as they finished our pool. I didn't have them plumb anything for it. There is only one valve you'll need and one backflow preventer and they both come with the solar system. Then you just cut into the return line and add the valve which will direct the water to your panels or bypass them. Then add a "Tee" for the water to come back from the panels. Nothing to it. And by the way, instead of hooking our solar system up to the control panel, we chose to put in an automatic thermostat control valve.