Beating the Heat in Dubai: Alternative Air Conditioning Refrigerants Show Big Gains at High Temperature

This post written by Alex Hillbrand, NRDC's HFC Technical Analyst

Concern about the efficiency of air conditioning in very hot climates has been an obstacle to winning agreement on a phase-down of the powerful heat-trapping chemicals known as HFCs (hydrofluorocarbons). Now we have new test data on the performance of next-generation refrigerants in air conditioners commonly used in homes and buildings.

The new data show that climate-friendlier alternatives perform better than the HFC most widely used in those products, R-410A, especially at very high temperatures. In short, climate-friendly solutions are available for air conditioning even in the hottest places on earth.

These results were presented at a technical workshop Saturday in Dubai, one day after countries agreed to start formal negotiations over HFC phase-down proposals. Saturday's seminar shows us that the next generation of air conditioning products will meet consumer needs for effective, energy efficient cooling in very hot climates.

Teams from Oak Ridge National Laboratory (ORNL), the Air-Conditioning, Heating, and Refrigeration Institute (AHRI), and the United Nations Environment Programme (UNEP) compared the cooling power and energy efficiency of two refrigerants currently used in today's equipment - R-410A and R-22 (an ozone-depleting HCFC, or hydrochlorofluorocarbon, being phased out under the Montreal Protocol) - with new alternatives that have only a fraction of the climate-warming impact when emitted into the atmosphere. (Both R-410A and R-22 trap about 2,000 times as much heat as carbon dioxide, pound for pound. The alternatives considered in these tests have only 1/3rd to 1/1000th the heat-trapping power of the two current compounds.)

The ORNL results show that two compounds, HFC-32 and DR-55, have better energy efficiency than R-410A at both medium and high ambient temperatures. And while they perform well at typical temperatures - 82°F (28°C) and 95°F (35°C) - their energy efficiency and cooling power show major bonuses over R-410A at 125°F (52°C) and above. In contrast, R-410A works reasonably well in temperatures found in much of the world, but its performance degrades quickly at very high temperatures.

The ORNL tests also demonstrate that R-290, or propane, yields impressive energy efficiency savings over R-22. R-290 is starting to be used in mini-split systems in India and China, with support from the Montreal Protocol's Multilateral Fund (MLF).

These tests may well understate the true advantage of the alternative refrigerants. In the studies, the alternative refrigerants were tested in existing air conditioners designed for R-410A and R-22. Performance should be even better when engineers improve equipment designs to optimize performance with the new refrigerants.

Importantly, the test results show that equipment manufacturers will be able to use HFC-32 and DR-55 in global products that will work even better than R-410A in very hot countries.

The current Montreal Protocol mandates deep cuts in the production and consumption of R-22 in 2020 in order to protect the ozone layer. If very hot countries rely on equipment that replaces R-22 with R-410A, instead of the better-performing alternative refrigerants, they will find themselves with air conditioners that that consume more energy than the next-generation products, and that do not cool as well. But if the Montreal Protocol parties here in Dubai kick off a transition to superior refrigerants, then people living in hot climates will be able to buy equipment that cools better, costs less to operate, and does far less damage if the coolant is emitted into the air.

Delegates from some of the high-temperature countries - Saudi Arabia, in particular - welcomed the research presented on Saturday, and encouraged more work to be done. They pointed out that while equipment performance looks excellent, challenges remain, including the need to develop safety standards and codes, ensure equipment availability, and train service technicians. These needs will require additional funding through the Montreal Protocol's Multilateral Fund.

In spite of these challenges, Dr. Walid Chakroun of Kuwait University and the UNEP High Ambient Project suggested that developing countries in hot climates would need just ten years to have all the details figured out and to ensure availability of climate-friendly equipment. An HFC amendment can accommodate these needs for extra time. For example, the North American HFC phase-down proposal calls for the first major cut in developing countries' HFC consumption in 2026.

The technical progress reviewed at the workshop is a good sign for progress on HFCs under the Montreal Protocol. It's not hot air-- keeping cool just got easier in the world's hottest countries.