25 kW Solar power project in Iowa.

[TheGoose]

Actually, I Have looked and there is very little in the form of a readily available solar powered A/C. There are systems that you can piece together such as Mitsubishi's mini-split and you can buy inverters and the like. There are some "fringe" companies out there....but there is, to my knowledge, not a main-stream, easily-obtainable solar-powered A/C out there.

Here is one that I found that looks promising: Kingtech solar Solar Air Conditioner | Affordable Solar Air Conditioning

[nomad]

Actually, I Have looked and there is very little in the form of a readily available solar powered A/C. There are systems that you can piece together such as Mitsubishi's mini-split and you can buy inverters and the like. There are some "fringe" companies out there....but there is, to my knowledge, not a main-stream, easily-obtainable solar-powered A/C out there. They are not "fringe", but, somethings like homemades and it has to be so cause they can not make bigger investments on production and toolings which are a lot of costs.

Here is one that I found that looks promising: Kingtech solar Solar Air Conditioner | Affordable Solar Air Conditioning

Reason that we have not seen many, good finished, solar air conditioners is big companies haven't put their weights on this system yet as there is no enough market (due to much cheaper grid electric prices.) Big companies are already at design or preparation stages. Clean energy products such as this solar a/c are mostly products of small companies who try to enter business quickly or products of small workshops. These solar a/c s can be sold to only places where there is no electric grid and this is a small market which can feed only small companies and workshops.

Look at the price of solar a/c in your link. 16000 btu (about 4.5 kw), a small energy for heating especially, costs 2900 USD which is a lot (comparing to 1500 USD for traditional a/c with the same heating power.) Who can buy this solar a/c? Not any person who has the grid, but, someone with no grid and 2900 USD for that device where there is no grid is a good price really. I predict, in a year or two, people with grid lines too will buy solar a/cs because not only their prices will reduce, but also, grid line electric rates too will increase. Then, we will see big companies in solar a/c fields more as there will be enough market.

My advice to people interested in using clean energies is that: don't hurry up if you have grid line electric, but, prepare yourself.. If you have no grid, then, don't wait and go for it, clean energy. Your use of clean energy in a place where there is no grid will have been a profit already even with these prices.

[TheGoose]

You have a good point on why the "Big Boys" have not gotten into the Solar A/C game.

I personally think solar A/C makes a lot of sense for several reasons, especially here in the Southen US. For one, when the sun is the strongest is when we need the A/C. I have not hardly turned my heater on this year, and using a nat. gas heater has gotten much much cheaper to operate. My electricity bill in the winter can run ~$100 in the winter and upwards of $300-400 in the summer and I am conservative with the thermostat. Many people I know are paying more than $500-600 a month to A/C their home with rates hovering around $.12 / KWH.

I think all the companies I have seen (kingtec) are going about it the wrong way. I believe they need to be looking at doing what the solar water pump guys are doing-turning the DC into A/C that then drives the motors at a speed that is set by the amount of the sun. That kingtec A/C that i looked at had a battery built into the unit. Not needed for a regular grid-tie system IMO. It should have a built-in inverter so that you plug it into the wall and then it uses whatever combo of A/C or D/C that it needs to run. How much cost could you eliminate getting rid of the charge controller and battery? You can buy a grundfos solar powered pump for about $1800-2000 retail (on-line, not brick and mortar) that is AC/DC ready-you just plug it into the panels and it will run as long as it gets 30-300VDC or 90-250 VAC. They leave it up to you to get the correct "controller", but you can plug it directly into the panels if you wish.

I am not looking to replace my central A/C...I am looking for ways to supplement it. Give me a ~1.5-2 ton solar ready AC that can run off of 2-4 panels that costs around $2k+panels+installation and I'm in. Panels right now are running about $200 for ~180-200 watts. 3-4 panels = $600-800.
AC = $1800, panels $700, rack = $200 (unsure on this price as I've never done roof-mount), and misc. wiring etc at $200. You should be able to do one for around $3,000.

It would be hard to do the math on payback but what kind of grid-tie system can you get for $3,000? Not much, and there are many, many regulations that will have to be followed and the power co's are making it very hard for the DIY. This would be the fastest way someone could quickly do their home with solar and off-set a major part of their utility bill. Of course, during the cooler months you probably would not be able to recoup any energy so that would have to be factored in. Unless you went with one of the "rogue" inverters that you can plug into a wall socket and grid tie your panels. I think the power-co would frown heavily on that one.

[nomad]

I think all the companies I have seen (kingtec) are going about it the wrong way. I believe they need to be looking at doing what the solar water pump guys are doing-turning the DC into A/C that then drives the motors at a speed that is set by the amount of the sun.

Are those guys turning DC systems into AC current systems? For that, I can think of the only one reason and it is for household appliances where solar pumps are located. Otherwise, using AC (not to confuse with air conditioner, A/C - I used AC for alternative current) is unnecessary and extra cost due to inverters, etc.

To my calculations (during a quotation for someone here), irrigation by solar is economically feasable only when it is drip irrigation system with DC powered pumps which are submersible solar powered dc pumps with no inverter, with no battery, etc. Pump will operate during the day and will fill, say, plastic tanks which will be installed, say, 5 ft above the ground so that a small power pump will be enough to deliver water through drip irrigation pipes and this irrigation will be done at nights only and this is good not to lose water by evaporation. By this way, main pump power, hence solar power required for irrigation will be half and then we can say solar water pumping is economical. Well, plastic big tanks are expensive? Used ones are very cheap. I recommend this to those who think solar powered irrigation system.

[TheGoose]

The solar pumps I work with turn DC (direct current) into AC (alternating current). In fact one of the pumps that i use turns the DC into 3-phase A/C. Of course, it's not pure sine-wave A/C, but more like a square form. The reason this is done is so that the frequency of the motor can be varied to match the intensity of the sun. This way the pump will still run when there is less sun. If you only have a system that will turn at say 3,000 rpm then you need a certain amount of solar energy before the equipment can be started.

On my systems I can do 3,000 gallons per day from one single 180W panel with a water level (head) of about 20-30 ft. These systems flow open ended, no pressure after the well to an open tank.

I'm not sure how well Solar A/C systems will work because there is the need to run the liquid freon over an expansion valve in order to obtain the cooling, therefore you may not be able to slow down the compressor etc. the way you can with a solar pump. This is why it makes more sense to have a hybrid system that plugs into a regular wall socket so that you can provide a percentage of the cooling with either solar or A/C.

[TheGoose]

BTW sorry about the hi-jack.

[Redneck in training]

Most solar cooling systems use absorption cycle. There are no compressors or any moving parts in the refrigeration system but there might be pumps and fans circulation media through heat exchangers. The problem is that high temperature is needed to separate water from in example ammonia. Therefore the system use some king of concentration of sun energy to achieve that. Google "absorption cycle air conditioning" and you will get lot of already available systems.

[dave1949]

On the idea of using a small pure sinewave generator to replace grid power to the inverter of a standard grid-tied system during a power outage, it looks like there is a need to also replace the infinite power sink that the grid represents to the inverter. Any excess power from the pv panels is going to be pushed to the generator, and I don't see any advertised that are made to handle that. I suppose a heat element in a water tank or something similar could be used to absorb excess pv panel power while disconnected from the grid.

My generator is 14 years old. It would be nice, when I have to replace it, to get something designed to work with a grid-tied system.

[Redneck in training]

On the idea of using a small pure sine wave generator to replace grid power to the inverter of a standard grid-tied system during a power outage, it looks like there is a need to also replace the infinite power sink that the grid represents to the inverter. Any excess power from the PV panels is going to be pushed to the generator, and I don't see any advertised that are made to handle that. I suppose a heat element in a water tank or something similar could be used to absorb excess pv panel power while disconnected from the grid.

My generator is 14 years old. It would be nice, when I have to replace it, to get something designed to work with a grid-tied system.

That might be good point worth investigation. The solar inverters have several trip limits and in general can work without a load. If the voltage goes to more than 260V or less than 210V or temperature of the inverter is high or frequency is off more than 0.5Hz they simply disconnect. There is no need to dump excess energy to dummy load. Therefore the generator should be also inverter because they keep frequency constant and I bet they have protection against reverse current built in. Perhaps somebody can confirm that.

[Redneck in training]

Our system passed wind load test today. Our place is on a top of a ridge so when it blows it blows strong. I am guessing we had sustained 60 mph wind for a while and in gusts even faster. I was able to lean against the wind in angle without falling down. So far no damage. When I went to see the arrays they were rock solid. The panels are encased in ice deposited last night when the rain was turning to snow. So not much production until it melts and slides off. Tomorrow supposed to sunny but cold so we will see what happens.