Powering your air conditioner with Solar panels off the grid

Posted by Felix Okoli on Thursday December 25, 2014 at 24:43:48:

Imagine being able to power your air conditioner without the need for sourcing power from the grid or PHCN

Is it possible to power an air conditioner using Solar panels? Well, yet it is. After publishing an article on Solar panels, I've received a lot of emails and questions from people asking how they can use it for their home and one of such question related to using it for an air conditioner.

One of the first things we need to know about powering an air conditioner using solar energy is the power requirement for the air conditioner. Once we've established how much power the air conditioning machine needs, then we'd be able to calculate how much solar power it needs and hence know the suitable solar panel to use.

There are different types of air conditioners and some of them use more power than others. As at 2014, most manufactured A/Cs are powered by Alternating Current(AC) while few are powered by Direct Current(DC). Since solar panels mostly generate DCs, it could save you money if you just hooked a solar panel to a DC air conditioner but in most cases, you'd need to hook it up first with a power inverter for powering air conditioners that make use of DC.

So how much power does your AC currently need? You can easily find this out by looking at the power section printed on the back or on it's specification. Different models of ACs tend to have different power requirements but most new ACs tend to be produced with lesser power needs than the old ones.

Let's assume that your A/C requires at most 1000 Watts of Power, you are gong to need a solar panel that can produce that amount of power and a bit more per hour. Perhaps, a 1200 Watt set of solar panels will do. Since you'd also need to power the A/C for an uninterrupted period of time and for the fact solar panels mostly depend on weather conditions, you are also going to need to have a power bank such as a deep cycle battery to store the charges generated by the Solar panels. The power bank will feed power to the Air conditioner while the Solar panel will charge the battery. If the A/C uses alternating current, then you'd also need to make use of a power inverter connected in between the battery and the air conditioner so that it will be able to convert the generated Direct current into the Alternating Current which is what your A/C will need for power.

What to do
===========
- Read the maximum power requirement for your air conditioner e.g. 1000 watts. It is normally printed on a side of the ac unit.

- Decide on the number of hours you want to power the a/c unit

- Calculate the Watt Hours e.g. 1200W * 1hr = 1200WH i.e. If you want to power it for 1 hr, then it will be 1200WH. For 4 hrs, it will be 4800 Watt Hours

- Also calculate the battery Amp Hours e.g. 17AH. You get this by dividing the Watt-Hours by 12 for a 12 Volt battery. So, for 1200WH, it will be 100AH. For 4 hrs, it will require a 12V 400 Ah battery capacity.

- Look for a solar panel that can generate enough Watts to be stored in your battery. It could be one that generates it every hour for 4 hrs. You just need to generate enough per day to be used by the air conditioner the next day for 4 hrs. You can calculate this by dividing the Watt-Hours we calculated by 0.85*4 hrs i.e. 4800WH/(0.85*4) => 1411 Watts. So, you'd need a Solar panel that can generate at least 1411 Watts per day under 4 hrs of sunlight but we can just make it up to 1500 Watts so that it can cover for any losses.

- Install the solar panels facing the Sun and connect it to a battery bank suited for it.

- Also connect a charge controller in-between the battery and solar panel so that the latter doesn't get over-charged.

- Connect the battery's output to an inverter if using an alternating current powered Air conditioner else it would be a direct connection if it's a D/C air conditioner.

Powering a 1200 Watt air conditioner with solar energy might be a bit too costly and so it's adviseable to get one with a lower power requirement and nowadays, newer model a/cs tend to come with a low max power of about 600 watts. Choosing that over one with higher power requirements can save you money since they require less costly solar panels.

Once you have your system all setup, you will be able to power your air conditioner off the grid and hence save money on your power bills.