HVAC Converting a Heat Source to Energy

[jmex]

Hello All,
I have some space outside my room which have sunlight all day. The room heats up to very high temperature. Is there any way I could use that heat to cool down my room without using solar panels?
Just a thought.

 

[Tom.G]

Probably not enough to be worth the time and trouble. What you have in the way of a "hot" room is what's known as 'low grade heat.'... that's heat that is annoying/uncomfortable but does not have enough recoverable energy to be useful.

If you have windows getting direct sun your best low-cost bet is to block the windows. Aluminium foil on the windows is the lowest cost improvement.

Next step could be: put up an awning, install a window air conditioner, or block the windows on the inside with some insulation panels - the kind made of Styrofoam with Aluminium foil on one or both sides. They are easy to cut with a sharp knife to fit the windows. Place with the Aluminium foil side facing outward.

A Linoleum knife or Hook knife works for cutting the panels. If you must use a saw, use a hacksaw blade with some tape on it for a handle. If using a saw, it will take forever to clean up the mess!

Of course if the wall is not insulated, the above will have limited effect. If an uninsulated wall is part of the problem, try to shade it from the Sun.

Adding wall insulation is a last, desperate step. You will have to drill a hole (3 or 4 inch diameter depending on what blower you use) into the space between each of the wall studs. It is usually done from the outside because it is a messy operation. The holes should be just below the room ceiling. Aim the blower hose downward during installation because the top of the space is usually open to the area above the ceiling. This is a partial improvement because there is often blockage due to bracing or fire-breaks installed between the studs. Also, don't forget the space below the windows.

Or, if the outdoor air is cooler, do the obvious - put a fan in an open window.

Cheers,
Tom

 

[Borek]

Probably one thing worth to add to "low grade heat". Whenever you have some source of heat and you think you can use it, think about the theoretical (as in: maximum, that you will never reach in practice) efficiency of the heat engine:

$$\eta = \frac {T_h - T_c}{T_c}$$

where T_h is the absolute temperature of the heat source, and T_c is the absolute temperature of the cold sink.

In your case these are probably something like T_h=315 K and T_c=293 (give or take 5-10 K), so at best you can convert around 7.5% of the available heat into work. That's one of reasons why we don't even bother in practice.

 

[Rive]

Is there any way I could use that heat to cool down my room without using solar panels?

You can google up 'absorption refrigerator' or 'absorption chiller' if you want.
So, in theory: yes, you can.
But in any practical sense, it just does not worth it at this scale.

 

[bob012345]

Hello All,
I have some space outside my room which have sunlight all day. The room heats up to very high temperature. Is there any way I could use that heat to cool down my room without using solar panels?
Just a thought.

By ‘cool down’ do you mean just not getting hot or do you mean actual cooling?