Hydrocarbons Growing Role in Efficient AC

In  a warming world, air conditioning (AC) use is expected to skyrocket. According to the International Energy Agency (IEA), the energy needs for space cooling will triple by 2050, with nearly 70% of the growth coming from the residential sector.

This means that energy-efficient AC systems will be a vital part of any plan aimed at curbing energy use and carbon emissions.

Natural refrigerants-based AC systems, in addition to eliminating high-GWP refrigerant emissions, have proven to be highly efficient, and figure to play a key role in the transition to more efficient AC over the next decade. Indeed, this represents the next great opportunity for natural refrigerants, following their more widespread adoption in refrigeration and heat pumps for hot water generation.

As an indicator of the efficiency of  natural refrigerants in room air conditioners (RACs), propane (R290) is being used by two of the eight finalists – Godrej-Boyce and S&S Design Startup Solution Pvt. Ltd. – in the competition for the US$1 million Global Cooling Prize

R290-based RACs have already begun to gain traction in some markets. Godrej sold 650,000 units between 2012 and 2019, 95% in India, said Santosh Salian, Product Group Head – Air Conditioners, Godrej Appliances, in an interview  last  year. “But, over the next five years, we are looking at key markets like [South Asia], Europe and the Middle East for exports of our AC products.”

Godrej phased out its fixed-speed  R290 ACs and has been focusing on inverter units, which have ISEERs (Indian Seasonal Efficiency Ratios) ranging from 4.55 to 6.15. This puts them in “one of the highest ISEER rating categories in the Indian market,” said Salian.

“With its GWP as low as three, zero ODP, non-toxicity and excellent thermodynamic properties, [R290] is the future of the residential room AC industry,” he added.

The R290 charge in Godrej ACs is in line with European EN378 Standards and ranges from 300g to 380g, said Salian. But the charge limit for RACs is expected to increase next year with a change in the International Electrotechnical Commission (IEC)’s safety standard. 

Chinese manufacturers have also begun to produce R290 RAC units, with 276,250 units made as of October, according to  Li  Xiaoyan,  program  officer at China’s Ministry of Ecology and Environment/ Foreign Economic Cooperation Office  (MEE/FECO). The manufacturers are Gree, Midea, Haier, Hisense, Changhong, TCL, Aux and Yair.

R290 RAC units are slowly emerging in Europe. In March, a  briefing paper,  “HFCs  and HFC  alternatives in split air conditioning systems,” touted the potential of R290 AC for the European market.

“It seems technically possible to avoid f-gases today in new single split A/C with a cooling capacity below 7 kW [2TR] by using the refrigerant R290, unless where national legislation or codes prohibit its use, at good energy  efficiency  and at  a very  modest price increase that would likely disappear due to economies of scale if used at large scale,” wrote the authors, Barbara Gschrey and Julia Kleinschmidt of German researcher Öko-Recherche, and Stéphanie Barrault of environmental firm CITEPA.

To that end, an EU-backed project called LIFE ZEROGWP plans to come to market in 2021 with a monobloc double-duct RAC that uses R290. Launched in 2018, the project has an end date of June 30, 2021. “ZEROGWP project aim is to demonstrate the technical feasibility, full safety and commercial viability of an innovative monobloc residential air conditioning system, called Double Duct (DD) technology, that can be charged by R290 with unprecedented environmental performance,” said the project website.

A Midea R290 split air conditioner is also expected to enter the European marketplace, according to speakers at the online ATMO/DTI Technical Conference in June (organized by shecco, publisher of Accelerate.) The Midea unit is the only room AC to earn Germany’s highly demanding “Blue Angel” ecolabel.

Collin Bootsveld, Project Engineer, Belgium grocer Colruyt Group  is  looking forward  to  the availability of R290 ACs “I think that the most impactful development in 2021 will be the introduction of R290-based split air conditioning,” he said. “A British web shop already started selling these in the summer of 2020 and they have a monoblock version, for which you only need to drill two ventilation holes through the wall.”

“It is long overdue that Europe takes the lead here,” Bootsveld added, pointing to the positive environmental impact that R290 ACs could have if they become a worldwide standard.

I think that the most impactful development in 2021 will be the introduction of R290-based split air conditioning.

Collin Bootsveld, Colruyt Group

Colruyt Group is also running a “non-CE prototype” from Godrej in its labs. “ We have been giving feedback to them in terms of serviceability and the needs from a Western European perspective,” said Bootsveld, who is preparing a “business case” for R290 AC.

For commercial building applications, Polaris Technologies, an Australian HVAC OEM, launched hydrocarbon-based air-conditioning units in 2018. The units use M60, a hydrocarbon refrigerant blend from Engas consisting of under 35% propane, more than 60% propylene, less than 5% isobutane, and less than1% butane.

Polaris has installed more than 65 hydrocarbon systems in Australia in light-commercial applications, according to Tony Power, its Managing Director. A new version is being developed.

“We are in development after success of our initial release,” said Power. “We will be concentrating on hydrocarbon HVAC with special focus on built-in safety beyond the current ISO standards and, of course, high efficiency.”

Power sees manufacturers improving the technologies on all natural refrigerant [HVAC] systems, and he expects “significant energy efficiency gains beyond the high level that currently exists.”