I know heat from steam is used by steam engine. But I am interested in
heat present in atmosphere.

Say in summer the temperature is 30' C. So the air is at temperature
of 30' C. Can we take out heat from the air and make them temperature
20' C.

Lets calculate with 4' C temp difference the energy. The energy we get
by reducing temperature from 29' C to 25' C.

Specific heat of air: = 716 J/ Kg
Density of air = 1.09 Kg/ m^3

So for a air in a Hall 5 m by 5 m and height 4 m The total air volume
is 5 * 5 * 4 = 100 cu meter.

Heat gained by decreasing temperature by 1' C = Volume * Specific heat
= 100 * 716 Joules = 71600 J

So we can get 710 KJ of energy from a hall by reducing temperature by
10' C.

Lets say after cooling the hall to 20' C If we open the windows and
doors So that again the hall temperature reaches 30' C. And we can
generate the heat energy.

"Sanny" hotmail.com> wrote in message
news:50f540bd-efe7-48c5-a839-bd5d009495ba@q5g2000prf.googlegroups.com...

On Aug 19, 12:17 pm, Sanny hotmail.com> wrote:

[snip]

Sorry, no free lunch.

http://en.wikipedia.org/wiki/Carnot_heat_engine

"A heat engine acts by transferring energy from a warm region to a
cool region of space and, in the process, converting some of that
energy to mechanical work."

Where is your cooler region?

http://en.wikipedia.org/wiki/Carnot_efficiency#Efficiency

The theoretical maximum efficiency of any heat engine depends only on
the temperatures difference between the two heat sources that it
operates on. Sorry to disappoint “The Matrix” movie fans, but people
make lousy batteries.

--Mike Jr

Dear Sanny:

On Aug 19, 9:17 am, Sanny hotmail.com> wrote:
...

Works good for drying paint.

Not without a "cold sink". Heat is essentially "lost work", some of
which can be regained when it flows from hot to cold.

Consider the RTGs used by the Pioneer spacecraft. It used plutonium-
containing ceramic as the hot source, the 3 K background temperature
as a cold sink, and a thermopile to convert much of that waste heat
into electrical power.

And of course Nature does exactly what you suggest when she evaporates
water, let's it fall as rain, and lets it run donw rivers (where we
dam it and collect some of the work). And winds also derive from the
flow from hot to cold...

On Aug 19, 11:17 am, Sanny hotmail.com> wrote:

Sanny wrote:

[snip resat of crap]

1) Carnot cycle efficiency
2) Idiot

In article
<50f540bd-efe7-48c5-a839-bd5d009495ba@q5g2000prf.googlegroups.com>,
Sanny hotmail.com> wrote:

No, you can't. One of the laws of thermodynamics (you can look them up)
tells you the efficiency of any thermal-exchange system. It's a simple
formula involving the delta of the highest and lowest temperature in the
system and absolute zero.

Worse yet, trying to use body heat for anything means cooling off the
body whose heat you're trying to get. That would irritate me.

Just let the livestock into the house at night. It will definitely heat the
house.

On Aug 19, 1:11 pm, "Mike Jr." comcast.net> wrote:

One of my least favorite movies. However, you missed the point.
The implication of the movie is that most of us are experiencing a
virtual world which has the illusion of being reality. We think we are
experiencing a real world, but it is only a software simulation that
mimics some aspects of the real world as it was in the distant past.
Note that the virtual world doesn't have to be synonymous with the
real world, but it vaguely resembles it. The space ship, the
Nebuccadnezzer, exists in the real world as it is now. The pods exist
in the real world. However, the real world has different rules than
the virtual world.
In the virtual world of the matrix, the laws of physics as known
by scientists (also in this illusion) usually apply. Some people have
learned "software errors" that enable them to violate these laws in
specific ways. ...

Dear jjs:

On Aug 19, 2:00 pm, "jjs" wrote:

Some Native Americans would dig a pit, bury manure, and cover it over
with clay. Then they would pitch their tents over this biological
heater for the winter.

David A. Smith