[Walterhurley56]

Corrections: Big Bang is initial source of energy.
Every following reciprocation like mass-energy- and back with derivatives MUST be viewed as energy storage IF BB theory is correct.
2nd law does not include such calculus. Hence, all mistakes of interpretations.

Agree

[Dary]

Congrats OP. There's a patent (US20080127657A1) describing exactly what you were trying to explain.

Screen Shot 2015-11-14 at 10.53.56 AM.png (207.95 kB . 894x623 - viewed 8269 times)

US20080127657A1.pdf (533.81 kB - downloaded 619 times)

[McKay (OP)]

Congrats OP. There's a patent (US20080127657A1) describing exactly what you were trying to explain.

Woah, cool. But, apparently, nothing has come from it in the 10 years since its was filled. Either it really, fundamentally, doesnt work or its hard to get efficient enough thermo-electric generators or no one has tried, or both. I am sorry that I cannot explain my thoughts better, I am not smart.

Hmm, but if there is a patent and I, or someone else, actually build it and it does work as suggested - does that mean I would be braking some laws or something?

[Fredrik]

Say that you have temperature T1 on the outside and temperature T2 on the inside of the house.

The efficiency of a heatpump is given as (coefficient of performance, ideal carnot cycle): Heat out / Work in  = T2/(T2-T1).

Say that you use an ideal Stirling engine to transform back the heat energy to mechanical energy/work.
Then you get an efficiency of (Carnot cycle): Work out / heat in = (T2-T1)/T2

Total efficiency for the ideal system is then: (Heat out / work in) * (work out/heat in) = work out / work in= (T2*/(T2-T1)) *((T2-T1)/T2) = 1.

That is, you get as much mechanical work out as you put in. This is for an ideal system. If you look on real systems and also introduce that you have to transform electricity to mechanical work in the heatpump and mechanical work to electricity from the ideal Stirling engine, you'll end up with an efficiency below 1.

Your example assumed a thermoelectric converter. This device also requires a temperature difference to work and is limited in similar ways as my example above.

Would assume this is why we don't have selfpowered heatpumps. I got exactly the same idea as you this morning, found the thread and thought a little bit about it myself before writing my answer above. Maybe the idea would work if we introduce more heatsinks? For example take the heat from T1 and run the heat to electricity converter against heatsink T3 (the house is kept at temperature T2)? It would work if T3 is sufficiently lower than T2. Don't know if it's feasible in practise though. Not always that you have access to multiple heatsinks with different temperature directly outside the house.

[lalathros]

I have been thinking about the same idea in the last 3 days. I'm installing an Air-source Heat pump for hot water in my house and my mind has been blown by the COP of this system which is around 4. I've checked online that there are heat pumps with COP of 5 currently in the market.

I'm not an expert in any way, I have basic knowledge in Thermodynamics and science in general. After reading bit, I've been wondering, like McKay, why this system hasn't been made yet. I would love a discussion on how I could be wrong and understand what could be done to make a system that could use Ambient Heat energy.

Earth is warming up. We've been dumping CO2 into the atmosphere for so long that these molecules are trapping a large amount of heat, which is causing massive global catastrophes like the recent Hurricanes Harvey and Irma, melting of polar ice caps etc.

Using Solar PV converts incoming light energy to electricity. While this offsets equivalent generation of electricity from fossil fuels, it doesn't reverse the process of climate change that was done till now in any way. The case is the same with Geothermal, in my opinion. We are harnessing free clean energy, yes, but we are not reversing the effects of human activity of climate change. To do that, we should either absorb the CO2 in the atmosphere or reduce the average global temperature using some other method.

This is how I stumbled upon the idea of using this heat energy trapped into the atmosphere which we have dumped into the atmosphere in the first place.

A heat pump which generates hot water at 80°C that has a COP of 5, i.e. Input 1kW to Output 5kW, which is coupled with a steam generator that has a liquid with low boiling point which generates electricity with an efficiency of 40%, could give us approximately 5kW*40% = 2kW of electricity. (I'm aware I'm possibly wrong with a lot of things here, I would love if someone could explain how)

As for what Fredrik posted, the ground is an excellent heat sink. At a depth of 5-10 feet, we get a constant temperature all year round at 10-15°C. There would be no need to use extra energy to have a temperature difference for the heat sink.

Thanks for reading this. I've been meaning to post this but never had the courage to type it out thinking I was the only one with this idea. Its amazing to know that there are other people with the same idea and there is a patent as well!

[drmp3]

I was thinking about this too - if we have a 400% efficient way of heating something, surely we can make a power generator?

Sadly as mentioned in other posts thermodynamics rules this out. The same thing that means your heat pump can be 400% efficient also means that your Stirling engine (or whatever you use to generate electricity from the heat) can only be 1/400% = 25% efficient. Multiply the two together and you'll get 1 (or less than one in the real world). ie you'll lose more energy than you put in.

Basically the hotter the input to your electric generator, the more efficient it is. But the hotter the output of the heat pump, the less efficient it is. The two will always cancel out.

If this could work, you could e.g. use the electricity output to make a flywheel go faster and faster. Eventually you'll cool the world and the universe down to 0K and concentrate all the energy of the universe in the flywheel (you've reversed the big bang!). The 2nd law of thermodynamics says that energy always spreads out, and this is the opposite, so it's impossible, no matter how you tweak your heat pumps or generators.

[rich0815]

 I think you can by using the expansion medium air (water vapor is with these
 temperatures excluded)
I have to pre-compress the air medium from 20 degrees (celsius) to at least 20 bar. Then by heating it
at 60 degrees I get a pressure of 23 bar, i.e. a working pressure of 3 bar, with a cop
Value of 4 .This working pressure is converted to electricity by an expander/generator .
According to Carnot, if work is almost equal to electricity, an efficiency of 15% can be expected.
So I have 85% waste of heat energy that the system has.

 via the recompressor I just reuse it again.
Thus, an overall efficiency of more than 70% is achieved.
What do you say about that?
Any thinking mistakes ?

[alancalverd]

I was thinking about this too - if we have a 400% efficient way of heating something, surely we can make a power generator?

Or an unlimited fortune. Don't confuse COP with efficiency!

[alancalverd]

Hmm, but if there is a patent and I, or someone else, actually build it and it does work as suggested - does that mean I would be braking some laws or something?

Talk to the patentee  and agree a licence fee for any that you sell. He probably knows a bit about the actual manufacturing process and will be keen to get some return on his investment.

[evan_au]

The Cosmic Microwave Background Radiation (CMBR) has a temperature around 2.7 Kelvin (ie slightly above absolute zero).

Most of the black holes we have detected are surrounded by a swirling accretion disk at thousands of Kelvin - you could extract useful energy from the difference between this temperature and the CMBR.

In theory, you could also extract useful energy from an isolated black hole, which has no accretion disk.
- The event Horizon has an effective temperature measured in nanoKelvins (ie barely above absolute zero).
- You could use evaporation of Helium at low pressures to drive a "steam" engine from the CMBR (eg to power your quantum computer)

[passtere9]

I think I know what you mean, but perhaps you should explain these heat pumps a little more, there might be some confusion...