Running A Steam Engine with Powers

[Minuteman37]

In another thread of mine I'm discussing a fantasy setting currently undergoing an industrial revolution, but not by using Coal. Instead they're using heat generated by pyromancers to run steam engines.

I'm wondering just what would be the best way to go about this? My first instinct is to by temperature control in sufficient levels to heat the water sufficiently, but just how many levels? Or am I going about this wrong?

[Refplace]

Water boils at 100 degrees Celsius and 212 Farehint and GURPS uses Fareniet.
So assuming 32 degrees starting temperature (freezing) you need 9 levels of Temp Control.
45 base points, -50% heat only and another -30% in limitations its 9 points.
But requires concentration so you may want to buy that off.

That would heat the water up by 18 degrees a second which is pretty fast.

[Minuteman37]

Originally Posted by Refplace

Water boils at 100 degrees Celsius and 212 Farehint and GURPS uses Fareniet.
So assuming 32 degrees starting temperature (freezing) you need 9 levels of Temp Control.
45 base points, -50% heat only and another -30% in limitations its 9 points.
But requires concentration so you may want to buy that off.

That would heat the water up by 18 degrees a second which is pretty fast.

Is it really that simple? My understanding is that the steam in a steam engine is much hotter then the boiling point of water.

[Anaraxes]

Originally Posted by Minuteman37

Is it really that simple? My understanding is that the steam in a steam engine is much hotter then the boiling point of water.

It's the temperature of boiling water at the pressure inside the boiler, which is usually much higher than the standard atmosphere, and so also much hotter. This makes the engine more efficient, and also in the past occasionally made them explode. Your pyromancers are going to be limited by your smiths.

Here's a calculator if you know the pressure of a historical steam engine you're using as a model.

[Fred Brackin]

Originally Posted by Minuteman37

Is it really that simple? My understanding is that the steam in a steam engine is much hotter then the boiling point of water.

In the Real World you need to supply the energy for the phase change so that just heated water probably boils off at the rate of heating. The way it does in a pot on top of a stove.

You're still heating it faster than any normal way of doing it though. If you could heat it all in one second I'd have it explode.

[Varyon]

Originally Posted by Minuteman37

Is it really that simple? My understanding is that the steam in a steam engine is much hotter then the boiling point of water.

This is because a steam engine is a high pressure system. In fact, the steam probably isn't much hotter than the boiling point of water in that system, but it is much hotter than the boiling point of water at 1 atmosphere (higher pressure means you need higher temperature to cause boiling). So, you'd probably need more than 9 levels of Temperature Control to go from ice to steam in a high pressure system.
EDIT: Ninja'd. That'll teach me to look things up to confirm before hitting Submit :P

[Refplace]

Originally Posted by Minuteman37

Is it really that simple? My understanding is that the steam in a steam engine is much hotter then the boiling point of water.

Originally Posted by Anaraxes

It's the temperature of boiling water at the pressure inside the boiler, which is usually much higher than the standard atmosphere, and so also much hotter. This makes the engine more efficient, and also in the past occasionally made them explode. Your pyromancers are going to be limited by your smiths.

Here's a calculator if you know the pressure of a historical steam engine you're using as a model.

Thats a handy calc if you can find the pressure.
My method will work, but is more efficient at temperatures above freezing, assuming your boiler can handle the pressure. Also depends how math heavy or realistic you want to get.
Personally, depending on climate I would think 10 levels is plenty but I am no expert on steam engines. Wonder if the steampunk books list pressure?

[Kax]

Steam takes up 1600 times the volume of liquid water, no matter its temp. The hotter it is the more useful energy it contains, especially if you are using multiple staged cylinders. 383 F (195 C) is a reasonable normal operating temp. (taken from documentation).

From High-pressure_steam_locomotive: "A high-pressure steam locomotive is a steam locomotive with a boiler that operates at pressures well above what would be considered normal. In the later years of steam, boiler pressures were typically 200 to 250 psi (1.38 to 1.72 MPa). High-pressure locomotives can be considered to start at 350 psi (2.41 MPa), when special construction techniques become necessary, but some had boilers that operated at over 1,500 psi (10.34 MPa)."


If you're doing steampunk you can veer to the high side.

Of course if you have 'special' construction techniques you can go higher.

Also note: the spells Create Steam and Create Air are pretty killer when combined with pressure tanks that can hold the pressure and valves that won't explode under 1,600 atmospheres pressure....

[Minuteman37]

Originally Posted by Anaraxes

It's the temperature of boiling water at the pressure inside the boiler, which is usually much higher than the standard atmosphere, and so also much hotter. This makes the engine more efficient, and also in the past occasionally made them explode. Your pyromancers are going to be limited by your smiths.

Here's a calculator if you know the pressure of a historical steam engine you're using as a model.

Well that tool caps out at just over 700 degrees. And that would put an upper cap on the practical level for tempature control at being somthing like 34ish points.

[dcarson]

Since a sensible design recirculates the water after running it through a condenser your starting temp will often be just below boiling at normal pressure. New water to make up losses will often be used to cool the condenser si=o pretty warm also. So less FP needed to keep it running once hot.