Powering Air Conditioning and Refrigeration Systems with Solar Photovoltaics
23rd May 18
Cameron Quin

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:

  • Air conditioners and refrigerators use compressors, which require a power supply that can be counted on at any time.
  • Solar photovoltaic systems only generate electricity when exposed to sunshine. This means production drops to zero at night, and is reduced drastically with cloudy weather.

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.

Combining Solar Power with the Utility Grid

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.

Combining Solar Power with Batteries

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:

  • Being able to store enough energy to cover you nighttime consumption, plus a safety margin in case you get cloudy days with poor generation.
  • Being able to supply enough instantaneous power to meet the maximum demand that can be expected for your property.

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.

Conclusion

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.

  • Download our free guide to
    power purchase agreements 7 things you must know when dealing with PPA

new paper

Cameron Quin

23rd May 18
Cameron Quin

Cameron Quin has been heavily involved in business development from an early age. After founding and selling two online companies, Cameron found a strong passion for renewables and the opportunities it brings for the commercial and industrial sector. Sharing the possibilities of solar and the knowledge from the Solar Bay team is his favourite pastime.