Solar air conditioners come in two categories: conventional types that used a closed-loop system of refrigerant powered by an array of solar panels. This type simply uses the electricity from solar panels to power the pumping unit. It could just as easily be plugged into mains power.
As a general rule a 100 watt solar cannot run an air conditioner. The smallest portable air conditioners have an average power rating of 500 watts. A home air conditioner has an average consumption of 300 watts to 500 watts over a 24 hour period, but may draw up to 2500 watts at peak draw.
True solar air conditioning doesn’t use the sun’s energy to make electricity for the main part, but heats up water instead, which is a much more efficient way to convert solar energy. Paradoxically, this hot water is used with a system of drying tubes to draw heat from inside a house and cool it.
A 100 Watt Solar Panel Cannot Run An Air Conditioner
How Much Power Does An Air Conditioner Use?
Air conditioner power rating and consumption depends on the area of the rooms they service. Conventional air conditioners come in many sizes according to their usage:
|Room Size (sq,ft)||BTU Capacity||KW Rating|
Discover your solar saving potential
It’s pretty obvious that the bigger sizes would need a massive solar panel array to produce enough electricity to run them, particularly as pump motors run in cycles where surge currents draw heavy loads when starting up.
On the one hand, you need to keep the KW rating down and on the other it’s no good having insufficient cooling capacity. The answer could be to use a portable or hybrid air conditioning system and reduce the area that needs cooling. A hybrid system uses part mains electricity or battery, supplemented by solar panels.
How Much Power Does A Portable Air Conditioner Use?
The smallest mains powered portable air conditioner I’ve seen (I also own this) is 500 watts. It’s a little noisy but does provide adequate cooling for a room size of 100 square feet or so. Basically, one room of the house is designated a cold room in times of extreme heat, to give some relief in very hot weather.
500 watts equates to about 21700 BTU and costs around 2 to 3 cents to run per hour. Maybe we could run this unit with solar? First of all we need to verify just exactly how many watts a 100 watt solar panel can really produce!
How Much Power Can A 100 Watt Solar Panel Produce?
Solar panels are not created equal and two panels from different makes will not produce equal amounts of electricity. It always pays to go with an established and recommended supplier. The panels will perform and last a long time.
One thing in our favor is that mostly a.c. is need in the hottest part of the day, but even so, just one 100 watt panel is not going to cut it! The only time the panel will approach it’s peak output will be around mid-day, but that output will be far short of the wattage need to run our mini-air conditioner.
It’s more realistic to think in terms of kilowatt hours, that is how much power is needed over time. A general rule of thumb over a 24 hour period is to downgrade a solar panel’s power rating down to 20% of it full capacity. This takes into account reduced sunshine hours in the morning, afternoon and during the night.
How Many Solar Panels To Run An Air Conditioner?
Let’s assume you’re willing to reduce the hours you use air conditioning down to 5 of the hottest hours of the day, when the sun is at it’s strongest. We can assume that the panel would be pushing out close to it’s rated watts – let’s say 95 watts.
For the portable 500 watt unit described, on the face of it, we would need 500W divided by 90% which is 556 watts, or thereabouts. (This is not an exact science!)
However, 500 watts is the peak power rating and we can generally reduce that figure by 0.6 to get a realistic power requirement, which gives us about 300 watts supply capacity from the solar panels. It would be prudent to have 400 watts of solar panels installed. This is the installation I use for my own designated cold room.
But what about peak loads and brief periods of low or no sunshine? To ensure continuous running a battery should be connected through a solar inverter, so that power can be supplied in cloudy conditions.
Solar Panel Sizing Calculator For Air Conditioners
Find the annual energy usage in KWh for your air conditioner and enter it into the calculator. You’ll find this number on the nameplate or in the manufacturer’s specs. This figure is calculated over 1600 hours per year, which is about 4.5 hours running time per day.
Battery Air Conditioners And Solar Panels
There are many so-called battery operated air conditioners marketed, but very few are actually real a.c.units – most are evaporative ‘swamp cooler’ types. Recent developments in lithium polymer battery technology have made this a real possibility.
This unit fabricated in Australia has a 35Ah lithium battery on board constructed out of high power density 18650 cells. It can run for 5 hours on a single charge and I can’t wait to try it out. Peak power rating is 260 watts but it averages out at just 168 watts over that 5 hour period.
One of the coolest things about this a.c. unit (excuse the pun) is that it has a special adapter for charging the 24 volt battery with solar panels. The beauty of this set-up is that an inverter isn’t needed. Just hook up a set of folding solar panels and your ready to stay cool during camping.
Can You Run Air Conditioner Off Solar Panels?
Most air conditioners use too much power to be run by a few solar panels – a large solar panel installation would be required which may not be cost-effective.
What is the smallest portable air conditioner?
The smallest I have seen is 500 watts. It’s mains powered and seems to be about the lower limit for any medium sized room. Battery air conditioners do exist, and these are a great way to create a hybrid solar system where solar panels feed the battery.
What is a solar air conditioner?
Solar panels are used to provide electricity for a fan and other controls, but the sun’s thermal energy is used to heat water. Water is heated and then cooled in a process of evaporation and condensation to generate cold air.
The Video Below Demonstrates Recent Advances In Solar Air Conditioning