In residential and commercial buildings, air conditioning and refrigeration systems tend to have the highest energy consumption among electrical appliances. Considering this, many home and business owners ask themselves if cooling equipment can be powered with a photovoltaic array. The concept is viable, but there are some important technical factors to consider.
A question that gets asked frequently is whether you can power a refrigerator or air conditioner directly with conventional solar panels, without any connection to the electric utility network. Unfortunately, the answer is no, for the following reasons:
This leaves two options if you want solar-powered cooling: using the power supply from the utility grid along with solar panels, or using batteries.
When electricity consumers want solar-powered cooling, what they really want in most cases is to avoid the running cost of cooling equipment. This is possible without isolating solar panels, air conditioners and refrigerators from your electrical installation: you just have to size the commercial solar array large enough to offset the running cost of cooling systems, even if other appliances use the power output.
Assume you have an air conditioner that consumes 500 kWh per month. By using a solar PV system that generates that same amount each month, you are offsetting the energy consumption of the air conditioner. It doesn’t matter if the 500 kWh of solar generation were not used completely by the AC unit.
With this setup, you can benefit from the full-time availability of the power network while getting the savings from solar power.
If you are really serious about going off-grid with solar power, energy storage becomes mandatory. The battery array must be sized based on two requirements:
For an off-grid installation, purchase the most efficient cooling equipment available. This will reduce the power drawn for a given cooling load. Efficiency is normally indicated with the Coefficient of Performance (COP), a ratio of cooling output to power input. For example, an older air conditioner with a COP of 3 will draw twice as much power as a newer unit with a COP of 6, assuming both have the same cooling load.
If you want to maximise the financial return from solar-powered cooling, an isolated system is not recommended. Instead, you should focus on deploying a photovoltaic array with enough generation to offset your cooling expenses.
To avoid the upfront cost of a photovoltaic system, you can consider solar as a service. The system provider assumes all ownership costs and maintenance requirements, billing you a monthly fee based on the electricity delivered, at a price below the utility tariff.