Adding panels for window AC

rrroae · May 2011

Currently we have 4 Kycocera 205 watt panels which provides us with all the energy we need in summer. Usually we're at 100% capacity by 1 or 2 pm. Just ordered 4 more Kyocera 210 watt panels(basically the same as the 205's) in hopes of running a window AC during the day when humidity is at it's worst and also to help out in winter when we get little sun. I've read about the mini splits but don't have the money for one right now after buying the panels.

Looking to run this 10,000 btu Frigidaire that uses 925 watts and 8.8 amps. Like these units because they supposedly have low voltage startup but won't know how much difference it will make.

http://www.amazon.com/gp/product/B004P8K38C/ref=ox_sc_act_title_1?ie=UTF8&m=ATVPDKIKX0DER

Any thoughts or suggestions?

Cariboocoot · May 2011

Re: Adding panels for window AC

Yes. Off-grid systems are battery based, not panel based. Whereas it is true we frequently "load shift" to make use of solar power that would otherwise go unharvested, this is virtually impossible to do with something like an AC unit which is thermostatically controlled: it needs power whenever it determines it should be on.

So increasing the number of panels alone will not necessarily allow you to run the AC. You've got to have an inverter capable of handling the power demands and sufficient battery capacity to run it off from. If it the inverter is too small it will fault the moment the Ac comes on. If the battery bank is too small, even with additional panels, the system Voltage can drop suddenly when the AC comes on and again the inverter will fault.

If you could provide a few more details about the existing system (inverter make & model, nominal system Voltage & battery bank capacity in Amp hours, existing daily power needs) then it will be possible to determine how plausible this is and whether or not the additional panels will help.

Photowhit · May 2011

Re: Adding panels for window AC

My guess is you'll be close, I run a 5300 btu off of my 1300 watt array, after I reach float in the afternoon, and some at night. But I built the small cabin around the idea of airconditioning, Think walls, tightly built, so I have a pretty low duty cycle.

I think I would want to see the all the ratings for this unit as well as others in this range. My 4 year old smaller unit is 10.8 EER same as this unit, I would look for an energy star rated AC at least, shouldn't be too much more expensive.

Will your system handle all the extras? Charge controller, inverter, storage if you want to run it into the evening?

rrroae · May 2011

Re: Adding panels for window AC

This is how we're currently set up.

- Magnum Energy MS4024PAE 4000 Watt 120/240 inverter
- Morningstar TriStar 60 amp MPPT solar
- 4 Crown 395 Amp-Hour Deep Cycle 6 volt batteries wired for 24 volts
- 4 Kycoera 205 watt panels wired in series for 96 volts. Adding an additional 4 panels.

System is 24 volts and our battery bank capacity is about 150 amps before we hit 50%. On average, we use about 60 amps a day at 24 volts.

rrroae · May 2011

Re: Adding panels for window AC

Photowhit wrote: »

My guess is you'll be close, I run a 5300 btu off of my 1300 watt array, after I reach float in the afternoon, and some at night. But I built the small cabin around the idea of airconditioning, Think walls, tightly built, so I have a pretty low duty cycle.

I think I would want to see the all the ratings for this unit as well as others in this range. My 4 year old smaller unit is 10.8 EER same as this unit, I would look for an energy star rated AC at least, shouldn't be too much more expensive.

Will your system handle all the extras? Charge controller, inverter, storage if you want to run it into the evening?

Last year we ran a 5,000 watt window unit but it was drawing 540 watts on our killowatt meter and the AC did little to cool our place. After having a heating and cooling contractor come out for an estimate on a mini split, we found we need a 10,000 btu unit.

Our home is well insulated and stays cool until around 1pm which is around the time our system is fully charged. Hoping we could run the AC for about 4-5 hrs in the afternoon when the humidity gets miserable. Seems like our system should handle it but not quite sure.

rrroae · May 2011

Re: Adding panels for window AC

Also, does anyone know if they still make natural gas window ac units?

I remember hearing about these but can't find any info. We have a couple gas wells on our property which are used for the majority of our appliances and it would be great if we could use the free gas for an ac.

techntrek · May 2011

Re: Adding panels for window AC

I believe I read about air-sourced LPG/NG-powered A/C pumps (ground units not window units) in Homepower a few years ago. You could try searching on their site.

Blackcherry04 · May 2011

Re: Adding panels for window AC

You really have to run the A/C some to get a line on what you'll use. A lot depends on what you can live with on the temperature. It's the compressor that eats up the power.

Here's my routine, I keep it about 77 deg in the day time. The biggest heat load will be in the afternoon and early evening, I have enough panels and battery to cover that. I have a Honda EU 2000 and I'll run it during the dinner hour with a charger if I need it. ( usually not ), I crank it down a little cooler (75 ). About 9:00 I'll start then Generator again with the charger and turn the A/C as low as it will go, I get the bedroom down as cold as possible. After about a hour , I'll get down to 68 deg or so, then turn the generator off and set the A/C thermostat up to 75 deg. Many nights the A/C compressor may only come on 2-3 times for a couple minutes.

I have marks around the dial, so it makes it quick and easy to set it to the right temperature.

rrroae · May 2011

Re: Adding panels for window AC

Blackcherry04 wrote: »

You really have to run the A/C some to get a line on what you'll use. A lot depends on what you can live with on the temperature. It's the compressor that eats up the power.

Here's my routine, I keep it about 77 deg in the day time. The biggest heat load will be in the afternoon and early evening, I have enough panels and battery to cover that. I have a Honda EU 2000 and I'll run it during the dinner hour with a charger if I need it. ( usually not ), I crank it down a little cooler (75 ). About 9:00 I'll start then Generator again with the charger and turn the A/C as low as it will go, I get the bedroom down as cold as possible. After about a hour , I'll get down to 68 deg or so, then turn the generator off and set the A/C thermostat up to 75 deg. Many nights the A/C compressor may only come on 2-3 times for a couple minutes.

I have marks around the dial, so it makes it quick and easy to set it to the right temperature.

Sounds like a good idea. Also have the EU2000 and I need it cool before I can sleep.

When I think about it, I should have just bought a Generac generator like someone mentioned instead of getting the extra panels. I have all the natural gas I could ever use and I could have bought an AC for every room if I felt like it and run them basically for free.

*sigh*

Well, that will have to be the next project. Still glad I bought the panels.

solarvic · May 2011

Re: Adding panels for window AC

http://www.robur.com/products/ Here is a company that makes lots of products to burn your gas. They have a heatpump that runs with natural gas. There is a distributor in Buffalo ny. They wanted me to be a dealer but I wanted to retire. Solarvic

Adding panels for window AC

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