Heat pumps extract energy from the environment. But such machines require for their operation a significant amount of energy often from a power network.
Stirling engines are heat engines that operate with a temperature difference between two fluids.
But to achieve an efficient operation, this temperature difference must be high and the pressure in the engine, about 150 bar, hence the need to implement expensive technology.
The new engine produces energy instead of consuming and it works with large as with low temperature differences and low pressures.
The watertight chamber contains here a fluid that expands and contracts alternately depending on whether the fluid that surrounds it is hotter then colder than the previous fluid alternately provided by the distributor of entry.
These fluids at different temperatures can be, in the basic version, first ambient air heated by thermal solar panels and other air at temperature almost constant provided by a Canadian well.
A Canadian well produces air at a temperature ranging from about 13°C to 15°C (55°F to
59°F) during all the year if the pipes are buried 1.5 to 2 meters minimum.
This is thus geothermal energy so virtually inexhaustible on a human scale.
We can use the air in the exchanger but also water, steam or a specific fluid.
The piston will move rather slowly, but the propellers of large wind turbines turn slowly (about 15 rpm) and as yet they generate electricity with a series of gears that increase the speed of rotation that drives the alternator.
The animation runs at 15 rpm. It is found that the heat exchanges have time to do.
With the use of a multiplier, we can transform
power at low speed and high torque produced by the piston, in
power at high speed and low torque used by the alternator.
It must be remembered that, for example, the mechanical efficiency of the series of gears from a large machine is approximately 97 or 98%.
A multiplier with an efficiency of 98%: HERE.
So speed rotation is not a problem, just get a torque important enough for the whole to be effective.
Several types of distributors are possible, for example rotary distributors or by valves or by solenoid valves.....
| Model of exchanger more efficient.|
With heat exchanger with plates separated by flexible joints, hot and cold alternating with high-speed should be bearable by avoiding welds eg.
Examples of plates:
Examples of pressure:
with 0.1kg/cm² (~0.1bar), on one side with a single piston effect and one exchanger:
- on a 16cm diameter piston (~200cm²), the force is 20kg
- on a 50,5cm diameter piston (~2 000cm²), the force is 200kg
with 1kg/cm² (~1bar), on one side with a single piston effect and one exchanger:
- on a 16cm diameter piston (~200cm²), the force is 200kg
- on a 50,5cm diameter piston (~2 000cm²), the force is 2 000kg
Plates heat exchangers can withstand a pressure of several bars continuously.
It is too possible to use exchangers with tubes that can be improve by oval tubes.
In this form, at least one fluid through a compression chamber where it is put under pressure by a pump or a turbine or a compressor or other means producing the same effect so that when the Input distributor releases the passage of fluid, the fluid is injected under pressure in the heat exchanger allowing heat exchange with a larger volume of fluid and with a more rapid change.
When the fluid in question is a liquid, it can not be compressed, the compression chamber then has a deformable part by varying the pressure or volume tight annexe that it can be compressed.
Particular forms of fluid conduits or out of the chamber compression can also participate in the pressurized fluid before it enters the heat exchanger.
Compress and relax gases will change the temperature at one point but the overall result of these two operations will be almost zero as the temperature variation of gas.
By having two heat exchangers can improve the operation by the simultaneous action on both sides of the piston is "pulled" and pushed.
A detailed operation is presented below.
|Thermic solar panel, simple, inexpensive to produce, air circulating between a black background isolated, folded sheet and cut to obtain a large contact surface with air and double glazing.|
The good panels of this type reach an output of 80%. Regardless, here, the ventilation that is only a few tens of watts.
A panel of 10m² can provide
12,000kwh/year more than 32 kWh (average) for 365 days each year.
It is also possible to usedes vacuum tube collectors with transfer to a liquid, more expensive, more complex but also to increase the temperature of several tens of degrees.
Especially effective in summer to create the hot fluid, the "cold" fluid being then the air out of the Canadian well at 13 or 15°C (55 or 59°F).
In winter, the 13°C (55°F) makes the hot air in relation to ambient air at 0°C (32°F).
In winter, it can also lead the air of the Provencal well through the solar panel to increase its temperature, even weakly, before being injected into the exchanger.
These changes can be done automatically with thermal switches and solenoid valves.
|Comparing the periods of full operation of a wind turbine or electric solar panels, it seems that this machine should run longer and therefore provide more electricity for 24 hours and 365 days for a smaller investment to equal power.|
"Demension of Canadian wells" and power to see here on page 8:
834 kWh / year recovered for the heating period of six months for a tube of Ø100mm 50m long and 2m deep.
For 10 tubes and for one year, the thermic energy exchanged is:
834 x 2 x 10 = ± 16,000 kWh that is to say about 44 kWh for each 365 days of the year.
Provided that, in the summer, the well absorbes energy as a source of cold but for the thermic engine there is always a thermic exchange with production of energy regardless of the direction of the exchange in the well . And for the well, it is "charging" for the winter, it stores calories.
And the well works when you arrange the ducts under a building before its construction.
Companies ensure Canadian wells 50 years, there is no reason why they do not last longer.
|Canadian well + heat panel (10m²) = |
16,000kWh + 12,000kWh = 28,000kWh/year that is to say 76 kWh/day
To be at average production of electricity in France of
10m² of photovoltaic panels (2.825 kWh/day, 1,031kWh/year),
would require that the engine has an output of 3.72% (x 1.05 to reflect an output of 95% of the electric generator) = 3.9%
Should be able to do much better.
An electrical efficiency of 10% would make
7.6 kWh/day (2,800 kWh/year) (per 10m² of panels)
AND it is 68 kWh/day of heat energy used for another purpose.
Using the example of a piston of Ø 16cm and a 16cm stroke:
V1/T1 = V3/T3
V = volume in liters or cubic decimeters
T = temperature in Kelvin degrees 15°C (59°F)= 288 K and 100°C (212°F) = 373 K
V3 = V1 T3/T1
V3 = V1 + V2
V2 = 0.8dm x 0.8 x 3.14 x 1.6 = 3.2 dm³ (or liters)
T3/T1 = 373/288 = 1.3
1.3V1 - V1 = 3.2 dm³
V1 = 3.2/0.3 = 10.8 dm³
V3 = 10.8 + 3.2 = 14 dm³ (values are rounded)
A At the same resting pressure of 1 bar inside and outside balance.
B At identical volume, heating V1 from 15°C (59°F)to 100°C (212°F),
the pressure increases from 1 bar to 1.3 bar.
The force exerted on the cylinder face is:
8cm x 8 x 3.14 = 200 cm² x 1.3 kg/cm² = 260 kg
On the other side, the piston supports the atmospheric pressure of 1 bar that is to say a force:
200cm² x 1 kg/cm² = 200 kg
The resultant is a force of 60 kg (260 - 200) on the inside of the piston.
C When the piston moved up after stroke at constant temperature, with a larger volume, the pressure has fallen to 1 bar and there is an equilibrium with atmospheric pressure.
The piston is no more pushed.
D At identical volume, while cooling from 100°C (212°F) to 15°C (59°F),
the pressure increases from 1 bar to 0.77bar.
Inner force is
200 cm² x 0.77 kg/cm² = 154 kg
The external force being unchanged, 200 kg, the piston returns to its original position,
pushed by a force of 46 kg (200 - 154).
The forces are different, but we see that the piston works in both directions.
Presentation deliberately simplified because the gas temperature does not instantly for example 15°C (59°F) to 100°C (212°F) although this operation can be very fast between the plates.
In this particular use, the nature of the plates, their surface, their thickness should be studied more carefully than for a conventional use of a heat exchanger continuously. Copper (copper-nickel) will give the best thermal conductivity.
|When we do without the Canadian well, it must be to increase the surface of heat solar pannels or provide thermic energy by another means to have the use of enough energy to be converted.|
Force exerted on the piston with this setup and a difference of
70°C (126°F) (100 - 30°C (212 - 86°F)in summer and 70 - 0°C (158 - 32°F) in winter) that is to say 373 K/303 K = 1.24 on average
-> difference in pressure with the outside: 0.24 kg/cm² (1.24 - 1):
200cm² x 0.24kg/cm² = 48kg
and back force with 0.81 kg/cm² that is to say a differential pressure with the outside (which is 1kg/cm² ~1bar) 1 - 0.81 = 0.19 kg/cm²:
200cm² x 0.19kg/cm² = 38kg
Example of a double acting piston,
the same facilities and a second heat exchanger:
E At rest pressures identical within each exchanger balance.
200 cm² x 0.885 kg/cm² = 177 kg
F Heating one side of piston causes it to move to the cold side, with a reduced force as initially warm side volume is already "expanded".
G Arriving at the end of the stroke, the pressures are equal on each side of the piston which is in a rest that will not last because at this moment the cold side is heated and the pressure increases (where H).
H After starting, the operation actually starts here with the forces at work in actual use, 260kg - 154kg =
106 kg applied to the piston in either direction
(max force but not continuous, the force increases to 106kg, then decreases until 0kg, again from 0kg to 106kg in the other direction).
As we apply an ignition advance for internal combustion engines, it will be useful in applying an advance of the temperature changes by the distributor before the piston reaches the end of the stroke so there is less response time to leave in the other direction with more force.
We can also provide valves in the end cylinder to control pressure changes, although it complicates the device.
It is found that the engine operates at low temperature and low pressure when compared for example to a Stirling engine.
This implies a simplified technology.
Combined with the deep geothermal:
to 300°F and more.
Without fossil energy source, it is possible to have both electrical and thermal energy as needed with only two inexhaustible sources of energy on a human scale, geothermal and solar.
In this case, between 60°F and 250°F, the theoretical output is 24% for electricity production, plus the recovery of thermal energy in cogeneration.
Here is a possible arrangement in collective use:
1 A pumping means
2 is going up hot water from a layer of water by a first drilling
3 which optionally passes through a thermic solar panel
4 and supplies the device
5 the cold source can be a Canadian well (geothermal) or ambient air or another source
6 which generates electricity by an electric generator
7 which is transported by an electrical network
8 for powering buildings in common use,
+ recharging electric cars (14).
9 at the output device (4), the water is about 120°F, which allows overall heat exchanger or multiple (one per building) to provide hot water between 105 and 120°F in addition to heating.
10 cold water back into the layer of water to warm up again
11 by a second drilling.
12 One could possibly recover at least part of the outgoing water
13 to extract more heat energy by a heat pump (HP which consumes power when the device produces).
+ thermal energy 24 hours a day for each 365 days of the year
| Example of representation among others possibilities:|
- Speed expected 100rpm (another speeds are possible, we must choose the speed best suited based on the materials used, the rate of heat transfer and the fluids, especially in the enclosure.)
- Piston Ø: 16cm (0.16m)
- Stroke: 16cm (0.16m)
- distributor disk
- size of the plates (arbitrarily): 60cm x 60cm (0.6m)
- piston stroke B in 0.3 s that is to say 0.16 m / 0.3 s = 0.533m/s = 1.92km/h
- thickness of the distributor: 10cm (0.1 meters)
- speed of movement of fluid (hot or cold) between plates: A = 0.55m by 0.3s
0.45m + 0.1m / 0.3s = 1.83m/s = 6.6km/h
It is the minimum speed de circulation, of movement, greater speed allows more exchanges between the plates and fluids.
The hot fluid is air here, although steam is more effective even at relatively low temperature, after turning a turbine, through the operation of the machine even with a small temperature difference.
The hot fluid H is shown in pink to allow its identification with the sealed chamber, to be exact, it would be anything in red.
The distributor disk is shown in extreme position even though its position is determined according to the advance relative to the extreme positions of the piston.
The distributor disc and the engine run at the same speed.
If the disk is electrically connected non-directly to the motor, it is the speed of the disc that determines the engine speed to maximum speed that can reach the engine.
The extractor is not essential but it improves the operation.
Dimensions of the machine are one order of magnitude. Other arrangement of the elements would allow a smaller volume.
For example, the cylinder and the piston can largely be inserted in the exchanger with plates form adapted.
The structure keeping the plates is not represented.
|In this configuration, the disk valve is opened 90° to let the hot and cold fluids alternately.|
At first glance one might think that the distribution will take place according to figures 1, 2, 3 and 4 with dead time significant at 2 and 4 that would eliminate half the time, the action of fluids.
In fact, as shown in Figures 5 to 9 for the hot side, each fluid is introduced, at least partially, for almost 270°.
For the efficiency of the movement of fluid is maximized, it must find, as each machine, a compromise between the pressure exerted by the compressor (and energy absorbed) and overall efficiency observed.
- Both because it takes heat to convert it into electricity,
- And because the electricity does not add heat from a hydrocarbon
or greenhouse gas emissions to be produced.
The availability of many cheap energy is the future not only for transportation, for our comfort and for all uses that we know
... also ...
for others new applications, for example, provide fresh water, transporting it, producing fresh water from sea water ...
See HERE an example of this test sheeting to keep a glacier ice and the water reserve it represents.