The concept of Direct Thermal Leveraging

Simple mechanical levers are well understood and we all use them in our everyday lives.
The simple act of pulling a nail with a claw hammer is one example.  The concept is illustrated in the diagram below. A force F1 applied to one end of a lever, which could be a simple 2 x 4, produces a force F2 on the other end of the lever.
The forces are related by the simple formula: F1 multiplied by its distance D1 to the pivot point (fulcrum) is equal to F2 multiplied it’s its distance D2 to the pivot point.  If D2 is less than D1 than F2 must be greater than F1.  This fact discovered centuries ago lead to the still famous statement made by Archimedes some 2200 years ago: “Give me a lever long enough and a fulcrum on which to place it and I shall move the world”.

A similar statement could be made relative to heat;
Give me two large thermal masses at different temperatures and I can get something of any thermal mass as hot or as cold as you want. And this can be achieved with no man made energy source.

The idea is shown below. The “lever” will be something more complex than a 2x4 but the formulas are easily derived from the laws of thermal dynamics, using the well-known formula for the Carnot cycles for a heat engine and a heat pump.
For any nitpicking mathematicians, chemist or physicist out there, the formula assumes that all heat flow directions are positive in the direction of the arrows and delta T’s are all positive.




In the thermal leverage diagram, the red oval represents a large source of heat at a temperature of TH1,
The green oval represents a large heat sink at a temperature TL1. TH1 must be higher than TL1..
These two source/sinks could be the surrounding atmosphere, the earth, a large body of water, an object heated by the sun, a source of ground water etc.
We tap into the natural heat flow from TH1 to TL1 and leverage that flow to pump heat from the yellow body Tsource to the orange body Tdest.

Example:
A group of picnickers wish to keep a refrigerated container at 45 degrees throughout the day.
The air temperature is 90 degrees F. There is a small stream flowing through their picnic area with a constant temperature of 60 degrees F.  They know that the refrigerated container will require about 250 BTU/hr to stay at 45 degrees.

To use the above formula temperatures must be converted to an absolute scale (one where 0 is absolute 0). For calculation purposes we will use the Rankine scale.
The conversion formula is ﹾR= ﹾF + 459.67
They’ll use the air as TH1, The stream will provide the sink TL1 and and also Tdest.
The refrigerated container is Tsource which is set 45ﹾ F
Converting all temperatures to rankine we get:
TH1 = 549.67 ﹾR TL1= 519.67 ﹾR
Tsource = 504.67 ﹾR Tdest = 519.67 ﹾR
ΔT1 = 30 ﹾR and ΔT2 = 15 ﹾR
QH2 is 250 BTU/hr


QH2 divided by Tsource times ΔT2 equals 62.5
QH1 can be calculated by simple algebra QH1 =( 62.5 *549.67) /30.
QH1 = 1145.15 BTU/hr And QL1 = 1082.65 BTU/hr
Result: They’ll need to absorb about 1145 BTU/hr from the air and dump 1083 into the creek in order to get 250 BTU/hr of cooling at 45 ﹾF

The benefit is that it’s a free 250 BTUs/hr.

This can be improved by increasing TH1 by using a solar absorber.
For example by using a solar absorber at 120 ﹾF (579.67 ﹾR) for TH1, the amount of heat needed for QH1 is reduced to only 622.57 BTU/hr which can be achieved with a panel of about 2.5 square feet.  The solar absorber could be nothing more than a flat black piece of metal connected to something that can transmit the heat into the input of the lever.
To date, as far as I know there is nothing commercially available that can be used for a “Thermal Lever”.
The most promising devices available are built around the Stirling engine. Stirling engines are already being used in Arizona to achieve solar efficiency of about 30 %.
The Stirling engine has a cousin called a Stirling heat pump. By coupling a Stirling engine to a Stirling heat pump a thermal lever can be created.
There is an excellent Utube video describing the process and the device  https://www.youtube.com/watch?v=X1fiABe4x08

I got lost somewhere in this article.
I have to ask, did the picnikers have cold coffee by the time they understood what they were demonstrating?
I understand the lever principles, I use them a lot.
I understand Thermodynamics and its laws,
I know about British Thermal Units [ BTU ]
I have a solar absorber.
I have some questions;
- what is the distance between the fridge and the cool stream?
- will the picnikers sit near the stream with the mosquitos or in the sun 100ft away?
- what device will exiting between the stream and the fridge?
How many picnikers are there so I can replicate the experiment?
regards

John C Daley wrote:I got lost somewhere in this article.
I have to ask, did the picnikers have cold coffee by the time they understood what they were demonstrating?

I only know that I had to warm my coffee several times while developing this concept. I attached a pdf documant outlining the derivation.
I wrote it for readers who may not be as educated as you, so forgive me if it's over simplified.

John C Daley wrote: - what is the distance between the fridge and the cool stream?

The closer the better

John C Daley wrote:- will the picnickers sit near the stream with the mosquitos or in the sun 100ft away?

That's a common issue for any picnickers regardless of how the keep their food/drinks cold

John C Daley wrote:- what device will exiting between the stream and the fridge?

Well John, that’s the reason I posted this concept here. I’m hoping smart guys like you can figure out the thermal coupling devices that might work.

John C Daley wrote:- How many picnickers are there so I can replicate the experiment?

That number is limited by how much food/drinks a 250 BTU/hr refrigerator can hold and how much each eats and drinks

I think I'm getting my head round this.....

So we have two linked stirling devices, with the cold end of the engine in the stream, and the cold end of the heat pump in the refrigerator. The hot end of the engine is increased by a solar lens/black box, giving a larger temperature difference, and the hot end of the heat pump is still the air. So the engine rotation powers the pump which cools the refrigerator.
My physics is pretty rusty but it seems like it might work. According to the video the efficiency decreases with temperature difference, so you wouldn't get as much out as one would hope though.
On a tangent, I wonder whether you could use the hydro power of the stream to power a heat pump.....Now there's a separate thread subject, I wonder if we have another one on stirling heat pumps....

Very cool idea, but beer still tastes fine at 60f;)

Nancy Reading wrote:I think I'm getting my head round this.....

So we have two linked stirling devices, with the cold end of the engine in the stream, and the cold end of the heat pump in the refrigerator. The hot end of the engine is increased by a solar lens/black box, giving a larger temperature difference, and the hot end of the heat pump is still the air. So the engine rotation powers the pump which cools the refrigerator.
My physics is pretty rusty but it seems like it might work. According to the video the efficiency decreases with temperature difference, so you wouldn't get as much out as one would hope though.
On a tangent, I wonder whether you could use the hydro power of the stream to power a heat pump.....Now there's a separate thread subject, I wonder if we have another one on stirling heat pumps....

Check out the video    
The narrator mentions a company that is working on a system and may already have prototypes built.
All I'm trying to do is simply the idea by developing the concept of thermal torque.
All one has to do is calculate the thermal torque needed and then find a way to produce that torque from existing thermal masses.
You should absolutely be able to use the power of steam to power a heat pump.
It's being done by using a jet/venturi system in some facilities that have waste steam.

While steam can certainly power many things, Nancy was talking about a running stream of water...

Glenn Herbert wrote:While steam can certainly power many things, Nancy was talking about a running stream of water...

Sorry. My mistake. A friend of mine lives on an island in a river. He experimented with hydro generators, paddle wheels etc. but was only able to get a few watts. I did some research for him and found that it just wasn't possible to get any substantial energy without damming up the river to direct the flow into the hydro generator. Water is fluid and just flows around any obstructions including hydro generators, paddle wheels etc., unless forced to do so.

https://microhydrony.org/2017/08/27/calculate-maximum-power_draft/#:~:text=If%20a%20mass%20(M)%2C,M)(g)(h).

The hydro dam I work at uses the Venturi effect to increase megawatt capacity.

It has (2) Kaplan style runners with variable pitched blades embedded in penstock that use the Venturi principal to eek some more excited electrons to power the grid.

We are actually at 100% capacity right now, one of the few days a year we can pull it off. A combination of flow, low tail water and high head pond differential. It is only 16 megawatts but it’s still 100% for us.

You have to love hydropower!

Those types of turbines are called hydro kinetic turbines, of which there are many designs.

They are doing trials on the Penobscot River in Millinocket Maine using the paddle wheel kind, but no one is saying how many megs they are kicking out. That tells me a lot really.

I live on a river and intend to put in a hydro kinetic turbine, but to mechanically heat my domestic hot water as electricity is not a huge expense for me. Heat is a different story. I do have the capability though as my house is located between two commercial hydro dams with significant flows on the river