Windpowered Air Compressor

[ProsperoTaligent]

Windpowered Air Compressor

The prime mover of an air compressor that energizes the secondary circuit to the refrigeration circuit for HVAC is a Wind Turbine. In a scale experiment, one mini-split cooler/heater is utilized for harvesting thermal energy from inside of a shop. Another mini-split is utilized for harvesting thermal energy from the atmosphere outside of the shop. I want two redundant experiments of the same design for different conditions. The data of a unit installed in the garage can be gathered and the conditions of a unit installed curbside can be observed.

I don't know if you've seen guys on youtube who want to put a heatpump on everything? The heat pump when added to a hotwater heater can easily be 2 or 3 times more "efficient" at heating water. Improvements in efficiency of 100 and 200% are impossible. The heat pump heats better because it is absorbing thermal energy from the air and putting it in the water.

An air powered car has a device called a Phase Change Material Thermal Exchanger. It is paraffin wax that is heated to liquid and uses compressed air to discharge that thermal energy through rotary vane motors. The paraffin wax has a latent heat of 176kj/kg. A 1000w heat pump has 12,000btu of cooling power. 1kWh=3.6mj. 12,000btu = 12.660mj

Thats like the latent heat capacity of 84kg of paraffin wax. That's too much wax for that little mini-split-thermal-battery. I want to make it like 20kg and 3165kj capacity. So, the 20kg of paraffin wax is installed on the condenser sides of the mini-splits. Maybe, the outside generator should use more wax, 30kg? Inside of the wax is the condenser coil of the mini-split and the evaporation coil of a second circuit. It is an open circuit unlike the refrigeration cycle circuit. If I can expect the indoors mini split to perform 2-3 times better than electricity at heating wax, then I can expect a 1000w heat pump to require a rotary vane air motor to be 4hp to be of sufficient size, or three 1.7hp air motors turning the same axial flux permanent magnet alternator. The power from the compressor head, the wind power, can be saved up over time.

The amount of time that the compressor on the mini-split HVAC unit will take to charge the liquid wax from 50°C to 51°C is about 15minutes. The amount of time that I want to discharge the 3165kj of thermal energy and some of the energy from the wind turbine(unknown amount, 74cfm 144cfm 210cfm?) should be smaller, like 3minutes. I think, I will need more rotary vane motors than 2 or 3. If I, try to discharge 15 minutes worth of energy in 3 minutes, it will be 5x higher voltage.

I have convoluted unit exchanges in here, but I think this is true. I will need like an 8hp air motor, that does not exist, to capture this discharge efficiently, and this device is becoming too large for the scale of chemical electric battery I want to build. I will need 28c charge or something crazy. I wanted to use sealed lead acid. I guess I can make higher voltages with lead if I want.

Anyway, this is going to be a kickass endothermic golf cart. I think at a certain temperature, an endothermic golf cart could be capable of energizing all systems and making forward motion. Sometimes, the cart path, you can fry an egg on it.

For the endothermic golf cart, maybe I will reduce the thermal capacity of the battery to reduce the amount of time to discharge, so that I can lower the voltage of the circuit. Then, use parallels of this series circuit. If I had three thermal batteries that could charge in 7 minutes and discharge in 5 minutes, I can use the power of three to have continuous power, and use smaller cheaper 1.7hp rotary vanes.

On a day when it is 95°f and the cart path is 135°f, those batteries will charge faster than days when it is 70°f and the cart path is 82°f.

84kg/12 = 7kg
60min/12 = 5min
12,660kj/12 = 1055kj
5min*60sec= 360seconds
1055kj/360seconds = 2.93kilowatts or 3.3hp
1055kj/540seconds = 1.94kilowatts or 2.6hp

Its different discharging the thermal energy directly to the ground, than if I want to efficiently capture energy that I am discharging. Hypermilling.

 

[rjenkinsgb]

1kWh=1kj

A Joule is one watt-second.
One kilowatt for ONE Second is 1000 Joules.

A kilowatt-hour is 3.6 Megajoules.

You are also swapping units elsewhere.

 

[alec_t]

Anyway, this is going to be a kickass endothermic golf cart.

That will kill off the grass. It won't be popular with the golf course owner.

 

[schmitt trigger]

And…. Are you making a statement or asking a question? Your post is way, way too convoluted to be understood.

Why don’t you draw a thermal cycle diagram with its associated transfer function values, showing its conducted, radiated and convection paths?
Add all the system gain and losses and determine whether your whole system has a net positive/ negative energy balance.
For completeness, a T-S diagram for each conversion stage would allow you to understand the temperature range where each stage is producing or absorbing entropy.

 

[ProsperoTaligent]

A Joule is one watt-second.
One kilowatt for ONE Second is 1000 Joules.

A kilowatt-hour is 3.6 Megajoules.

You are also swapping units elsewhere.

I edited for those changes. 1kwh = 3.6mj 12,660btu = 12.66mj. I knew I made the mistake, I was working feverishly to try and imagine a scale at which this type of accumulator could be useful.

This scale would consume too much copper to cool a data center. We might have to apply the paraffin wax to our modems if we want to make the internet faster. Also, the distribution of "cooling the great outdoors" might be advisable. I think endothermic datacenters might disrupt the weather, creating derechos.

 

[ProsperoTaligent]

And…. Are you making a statement or asking a question? Your post is way, way too convoluted to be understood.

Why don’t you draw a thermal cycle diagram with its associated transfer function values, showing its conducted, radiated and convection paths?
Add all the system gain and losses and determine whether your whole system has a net positive/ negative energy balance.
For completeness, a T-S diagram for each conversion stage would allow you to understand the temperature range where each stage is producing or absorbing entropy.

I was making a statement. I am going off the grid. Its true that I wouldn't be able to regenerate, fully, the 12,660btu from the condenser. There is a paper that has a very good break down of the exogenics of this type of system.

Experimental Investigation of a Hybrid Compressed Air‐Electric Vehicle Prototype with PCM Based Heat Exchanger by Dr Ezra Alizade Ervin and Ibraham Dincer
The wikipedia on air powered cars misattributes the work by omission.

 

[rjenkinsgb]

I can't see where you allow for the energy used to charge the air reservoir in the first place?
You mention a wind turbine, but powering HVAC, in the first paragraph.

Also, while a heat pump gives an efficiency boost over direct heating - the inverse ratio is also true when using heat energy to produce mechanical or electrical power; after both processes, you get back less than you put in; tanstaafl.


If you just used banks of decent 18650 cells, you could store around 900kJ per kilogram (~20 cells per kg).

As most of the energy in a low speed vehicle is used for acceleration, overcoming friction and climbing slopes (all mass or weight dependant), I think you would likely get a better overall energy efficiency by eliminating the mass of wax and plumbing & sticking to electric power!

 

[ProsperoTaligent]

I can't see where you allow for the energy used to charge the air reservoir in the first place?
You mention a wind turbine, but powering HVAC, in the first paragraph.

Also, while a heat pump gives an efficiency boost over direct heating - the inverse ratio is also true when using heat energy to produce mechanical or electrical power; after both processes, you get back less than you put in; tanstaafl.


If you just used banks of decent 18650 cells, you could store around 900kJ per kilogram (~20 cells per kg).

As most of the energy in a low speed vehicle is used for acceleration, overcoming friction and climbing slopes (all mass or weight dependant), I think you would likely get a better overall energy efficiency by eliminating the mass of wax and plumbing & sticking to electric power!

It truly is not as practical for motorering than it is for home cooling. The mass of the wax alone is competitive with lithium, but you are probably correct that the plumbing tips the scales. Although, I am willing to prove otherwise.

 

[ProsperoTaligent]

It may be better to pursue cooling systems that utilize water as the PCM rather than Paraffin Wax. Water can freeze and thaw billions of times. Paraffin Wax probably undergoes some thermal degradation over time and becomes fodder for the hydrogen Corporate/US Government marriage, f-you dad I am going to be a body builder machine.

 

[rjenkinsgb]

I'd have thought a high temperature phase change would be more efficient, used with a low boiling point liquid to vaporise that for a motor or turbine, then condense & recycle it.

Or even something with a phase change over 100'C and use water as the circulating fluid?

You would probably find this interesting:

 

[Tony Stewart]

holy dorechos