Solar powered AC air conditioning, a bummer or a challenge?

[MarionReynolds]

It's interesting to try. Is this work for all window air conditioner models?

http://www.thegoodgears.com/Window-Air-Conditioner/

[Hkalan]

Can you tell me how do you get the total DC amperes in 24 hours? Do you use a special meter that record the DC amperes usage like the Kill-a-watt meter or the Utility AC watt hours meter? I love to get one of those DC meter so I can record my batteries uasage without guessing.
Thank you.

I use a Victron Energy battery monitor (Blue Power Panel), and each bank has a VE.Net Battery Controller that connects to the Blue Power Panel via CAT5 Network cables (daisy chain). It also has a VE.Bus to give me the full information of my Victron MultiPlus inverter/charger activities. I am able to monitor the energy consumed, in addition to many other features of each battery bank and inverter/charger. Living on the boat completely off grid for 15 years, I am a big fan for Victron and Morningstar equipment for reliability and monitoring.

VE.Net BPP System.jpg

http://www.victronenergy.com/battery-monitors/ve.net/

Alan

[GrandRiver]

PT,

I am new to the forum, but recently read a post (closed thread) by Sunking that leads you through the calculations required to design a off grid system.
Found it here>> http://www.solarpaneltalk.com/showth...ghlight=design

Sunking does a good job describing calculations plus end costs per KWh.

I would also offer my personal experience of 12 years of living with off-grid power. I can assure you that my per KWh costs have been well above what the local utility charges (approx $.10/KWh). I live where I do by choice, but would connect to the grid with no reservations if it was available.
Spending your $$$ on a grid tied system would be a better option to offset your cooling costs.

[paulcheung]

Hello,


After 24 hours for each unit individually tested... (windows opened and room equalised to 33C ambient outside temp between each test)

AC air conditioner consumed 148.12 DC amps
DC air conditioner consumed 149.52 DC amps

The AC unit compressor kicking in has a huge draw, and it goes on and off several times an hour... That adds up over a 24 hour period.

The DC unit just works at a steady and constant pace....


Alan... the happy fool

Can you tell me how do you get the total DC amperes in 24 hours? Do you use a special meter that record the DC amperes usage like the Kill-a-watt meter or the Utility AC watt hours meter? I love to get one of those DC meter so I can record my batteries uasage without guessing.
Thank you.

[Sunking]

Hello,

That sure looks good on paper...

I do not want to debate about the eBay TEC modules you compare to...

No one has even attempted to enquire about the TEC modules I had made for this. Your focus is on the simple fix and elsewhere.

Keep those CFC's flowing gentlemen !!!!! I going sailing today... while we still have an Ozone Layer !

Have a great weekend !

Alan

What is the EER of these Peltier units you have, and back it up with a link. It is very simple to understand just like mpg with a car. Which car goes further with a gallon of gas? One with 40 mpg or the one that gets 10 mpg.

[Hkalan]

Hello,

That sure looks good on paper...

I do not want to debate about the eBay TEC modules you compare to...

No one has even attempted to enquire about the TEC modules I had made for this. Your focus is on the simple fix and elsewhere.

Keep those CFC's flowing gentlemen !!!!! I going sailing today... while we still have an Ozone Layer !

Have a great weekend !

Alan

[Sunking]

AC air conditioner consumed 148.12 DC amps
DC air conditioner consumed 149.52 DC amps

The AC unit compressor kicking in has a huge draw, and it goes on and off several times an hour...

Watts is watt silly, and you want to know watt hours. The air conditioner draws 1777 watts from the battery. As you say th eair conditioner cycles on and off because it cools the room down quickly because it has 4 times the BTU cooling. The Air Conditioner runs on a duty cycle most likely around 25 to 40%. So in a 24 hours day only uses 1777 watts x 24 hours x .33 (duty cycle) = 14.07 Kwh in a day

Your DC air conditioner uses 1794 watts slightly higher than the airconditioner but runs continious and does not cycle because it is only has 1/4 the cooling BTU capacity. So 1794 watts x 24 hours = 43.-5 Kwh in a day almost 3 times the energy.

This is the part you do not get. Your Peltier cooling is extremely inefficient and cannot even come close to competing with even a inexpensive air conditioner. Your numbers prove it. You have chosen the most inefficient means to cool a room. Quit fooling yourself because you are not fooling us.

What you are missing is BTU cooling to Watt cooling capacity called EER. Most Window Shakers have an EER of 10. So a 6000 BTU window shaker with a EER of 10 will consume 6000 BTU's / 10 EER = 600 watts. A Peltier cooling has an EER around 2 or 3 which means for 6000 BTU of cooling will require 6000 BTU's / 3 EER = 2000 watts over 3 times as much power a gas compressor would consume..


EER = BTU's / Watts

[SunEagle]

Hello,

I have found that what is written for the specifications, and what the real world performance to be far from matching.

I have purchased a window sized "Compressed gas" air conditioner that cost $280 USD to compare a real life experiment with my $209 USD modified Peltier theory unit.

Although you are using "Watts" on a label to base facts to show I am a fool... I am following the DC amps that come from my battery bank to run the DC (modified rare-earth Peltier modules) air conditioner, and an AC powered "Compressed gas" air conditioner from the inverter, that is to be SO much more efficient...

Keep in mind, that DC amps to AC amps is far from the same !!!!

The room was maintained at 21 degrees C, and between 46-47% humidity.

After 24 hours for each unit individually tested... (windows opened and room equalised to 33C ambient outside temp between each test)

AC air conditioner consumed 148.12 DC amps
DC air conditioner consumed 149.52 DC amps

The AC unit compressor kicking in has a huge draw, and it goes on and off several times an hour... That adds up over a 24 hour period.

The DC unit just works at a steady and constant pace....

New question... What can I do with that nearly 2 whole DC amps I save by spending more money on the AC powered "Compressed gas" air conditioner ???

My purpose for all of this is to show that technology is continually improving, and we can take an old technology, improve it, and use it to our advantage.

Keep an open mind, and do some real experimenting yourself, rather then believing what labels have written on them... You may be surprised from the results !

The TEC modules I had made for this have possibilities... They can still be improved upon.

The only person I need to convince is myself, but I just wanted to share with you, that alternative methods of Air Conditioning exist.

Thanks,

Alan... the happy fool

I am interested in new research and hope you find something that is better than previous technology.

Be careful when you compare an AC and DC air conditioner efficiency. While you want to use a DC amps measurement you are not providing the energy data. You need to compare energy used (watts) to energy created (BTU/hr) to determine efficiency of a cooling or heating unit.

You also didn't provide a BTU rating of either unit so unless they were the same "size" a comparison of energy used may be incorrect.

[Hkalan]

Hello,

I have found that what is written for the specifications, and what the real world performance to be far from matching.

I have purchased a window sized "Compressed gas" air conditioner that cost $280 USD to compare a real life experiment with my $209 USD modified Peltier theory unit.

Although you are using "Watts" on a label to base facts to show I am a fool... I am following the DC amps that come from my battery bank to run the DC (modified rare-earth Peltier modules) air conditioner, and an AC powered "Compressed gas" air conditioner from the inverter, that is to be SO much more efficient...

Keep in mind, that DC amps to AC amps is far from the same !!!!

The room was maintained at 21 degrees C, and between 46-47% humidity.

After 24 hours for each unit individually tested... (windows opened and room equalised to 33C ambient outside temp between each test)

AC air conditioner consumed 148.12 DC amps
DC air conditioner consumed 149.52 DC amps

The AC unit compressor kicking in has a huge draw, and it goes on and off several times an hour... That adds up over a 24 hour period.

The DC unit just works at a steady and constant pace....

New question... What can I do with that nearly 2 whole DC amps I save by spending more money on the AC powered "Compressed gas" air conditioner ???

My purpose for all of this is to show that technology is continually improving, and we can take an old technology, improve it, and use it to our advantage.

Keep an open mind, and do some real experimenting yourself, rather then believing what labels have written on them... You may be surprised from the results !

The TEC modules I had made for this have possibilities... They can still be improved upon.

The only person I need to convince is myself, but I just wanted to share with you, that alternative methods of Air Conditioning exist.

Thanks,

Alan... the happy fool

[inetdog]

As far as mold goes, you probably have some in your air conditioner but that's nothing compared to the average swamp cooler. Along with their limitations they can be nasty after not being run for a while.

Two significant ways to control mold in a swamp cooler are to let the pads dry thoroughly between uses (not easy if the outside humidity is high, but you would not be using a swamp cooler then anyway) and draining the water sump periodically (some coolers do this automatically every N hours of running.)

[russ]

People just didn't seem to like having their homes half buried in the ground and dealing with the limitations and maintenance of the systems. Don't confuse a home built underground with earth tubes meaning tubes/tunnels that air can be drafted through. The underground home concept is valid. It takes advantage of low swings in ground temperature as compared to the atmospheric temperature swings.

As far as mold goes, you probably have some in your air conditioner but that's nothing compared to the average swamp cooler. Along with their limitations they can be nasty after not being run for a while.

Mould can grow anywhere true - a few hundred meters of dark and cool earth tube is a heck of a lot more problematic than an AC or swamp cooler that can be cleaned.

[jimindenver]

Earth tubes, we called it ground cooling when I was in school for HVAC in the late 70's. We built homes with extremely low heating and cooling bills. People just didn't seem to like having their homes half buried in the ground and dealing with the limitations and maintenance of the systems. They only accept those things if there is really no other choice. Back then it was the embargo, today it's the environment driving it. Nothing has changed though, if it isn't plug in and turn on, it's a compromise.

As far as mold goes, you probably have some in your air conditioner but that's nothing compared to the average swamp cooler. Along with their limitations they can be nasty after not being run for a while.

[inetdog]

No sir the AC power comes from the engine. Now there are DC air conditioners made for Tractor Trailers and trains that use 24, 48, and 96 volt DC, but again the power is coming from the alternators.

There is a growing market for DC A/C for tractor trailers that can run off battery while the engine is shut off because of idling restrictions. In those cases efficient operation with minimal battery drain is a selling point. But the recharge of the batteries ultimately comes from the main engine alternator or from a small quiet auxiliary generator.

[Sunking]

I wonder if a truck/van air conditioner could be a solution for small rooms. There wouldn't be any inverter efficiency loss in that scenario. Nor would there be the inflated cost of a home DC air conditioner....
Thoughts anyone???

No sir the AC power comes from the engine. Now there are DC air conditioners made for Tractor Trailers and trains that use 24, 48, and 96 volt DC, but again the power is coming from the alternators.

Only way remotely possible is with DC powered Split Air Conditioning. There are quite a few out there. Marv Air makes one for Marine environments in 12 and 24 volts with 5000 and 7000 BTU models. The 5000 BTU 12 volt units pulls 400 watts and one of the least expensive at $4000.

[russ]

Earth tubes can work well in good environments (i.e. cold earth) Please name a few places

but don't work well in southern climates where the ground is warmer year-round. Ground temps don't vary like that

As with any cooling system you have to be careful with condensate management; if the water is allowed to sit in the tube you get mold and other problems. How do you prevent the condensation?

They also take up a lot of space. You need hundreds of feet of tubing to get good coupling to the earth. At least that I can agree with

But if you can manage all that you can get very cheap cooling, at least on days that aren't _too_ hot.

If frogs had wings they wouldn't skin their butt hopping. It is an idea flogged on green sites from time to time but not worth the problems plus a rather large volume of air is required.