Water pipe heat tape

In PRNY, propane is generally cheaper than electric.

Solar heat collection and heat saving options might work best for you.

- . Christopher A. Young learn more about Jesus .

mike wrote in news:mvajib$atq$ snipped-for-privacy@dont-email.me:

Not interesting. Horrifying. Or is that what you meant.

It's certainly gotten better in recent years, as the costs of the panels have come down. But last time I looked, what you say is true. Without subsidies, it's not cost effective as a replacement for grid power. But for a dedicated app, like just running the pumps, it would be worth looking at the actual numbers. I've only looked at whole house type, not scaled down, dedicated type. I know at least one company makes solar powered pool pumps.

Agree. That's a whole different ball game. Classic example is solar heat for a pool. Again, from the sketchy info here, I don't know what exactly it is she's doing. But the solar panels used to heat water for a swimming pool are cost effective. Problem there is they are not freeze proof and also won't be effective in winter. You'd need the way more expensive evacuated type to generate heat in winter.

OK I'll add that to my list of ideas/solutions. Thanks!

Doubt it. The common heat tapes are designed to keep water (barely) over the freezing temp. I'd expect them to work well below the 60F you want.

With this much water, I'd check with pet stores and see what they think. Propane is usually cheaper than electric as a fuel source.

Perhaps a propane residential water heater, and tempering valve?

- . Christopher A. Young learn more about Jesus .

It takes 1 BTU to heat a pound of water 1 degree. Let that pound of water *evaporate* and you've LOST ~1000BTU's!

I'd have to look it up, but I think the latent heat of fusion is 86 BTU per pound, and the heat of vaporization is about 550. But, it's been a long time since I needed that.

- . Christopher A. Young learn more about Jesus .

Would a water heater like that end up costing more in powering it?

As it evaporates, does it not warm the surrounding air?

My experience with heat, is that propane is cheaper than electric. In any, or, whatever form.

- . Christopher A. Young learn more about Jesus .

Muggles posted for all of us...

I don't think the pvc pipe would be a good conductor of the heat given off by the tape. Perhaps heater in the fish tank would be best.

I don't know anything about farming fish, but don't you need some water/air exchange to keep the oxygen level tolerable to the fish. If you just block the surface, what keeps the fish alive?

ok thanks for the info.

Right now we have some large aquarium heaters, but they use a lot of electricity.

We have air bubblers in the tanks. They work even if the tanks are covered.

To within a few (10?) percent, 1kJ = 1BTU. So, 1KJ/kg ~= 1BTU/2.2lb

Enthalpy of vaporization (water) is 2257 kJ/kg so ~1000BTU/lb

So, where do the bubbles go? Wherever that is is where the evaporation goes. The bubbles assist evaporation. The air flow also carries away the heat you're trying to contain. Best way is to use thick insulation and seal the area between the water and the insulation. But you can't have bubbles if you do that. You have to do the thermodynamics math for the whole system. It's very easy to spend a lot of money optimizing one thing, then ruin that optimization by some other optimization decision.

The bottom line is that you have losses from the system to the environment. You keep the temperature stable by adding heat equal to those losses. If you do that, what goes on inside the system is largely irrelevant when it comes to operating costs.

Anything solar only works during the day. But your greatest need is at night. Managing that requires the same amount of heat, but you need to store it at a higher temperature during the day and release it at night. That means you can't use the huge amount of water in the fish tank as the thermal mass...unless you like your fish well done.

Round in circles we go, with no definition of the actual problem. Cost more in power than what?

Any electric heating element is 100% efficient in producing heat. If that aquarium heater is producing X heat for Y KWH, any other electric heating element you replace it with, if it produces