The report, produced prior to this week’s Montreal Protocol meeting in Paris by renowned German Environmental research consultancy Öko-Recherche, maintains that this can be achieved in the short to medium term and without reduction in energy efficiency even at high ambient temperatures. It has been produced as part of Europe’s backing for a global phase-down of HFCs under the Montreal Protocol.
Öko-Recherche is the Frankfurt-based independent environmental research institution and consultancy best known for producing the 2011 F-gas review report for the European Commission which formed the basis of the changes now being introduced in Europe on January 1.
The new report – Alternatives to HCFCs/HFCs in developing countries with a focus on high ambient temperatures – emphasises that a successful reduction of the global warming impact relies heavily on a broad application of hydrocarbon refrigerants like R290, wherever it is feasible under the given safety standards.
The report maintains that 55% of HCFCs can be replaced by natural refrigerants and foam blowing agents and an additional 13% by HFOs in the short term. In addition, 22% of HCFCs could be replaced in the short term by HFCs with moderate GWP and by HFC/HFO blends in the medium term.
Alternatives for the remainder, it says, are not yet available at the same efficiency level and at feasible cost but are expected by 2025.
The subject also of a second report by Öko-Recherche (Green backing for R32 and HFO blends), hydrocarbon refrigerants like R290 are viewed by the German consultancy as highly energy efficient R22 replacements at both moderate and high ambient temperatures. Although limited by safety standards on charge sizes, most industrialised and many developing countries are already using hydrocarbons for equipment with small charges such as domestic refrigerators/freezers, commercial stand-alone equipment, and portable and window-mounted air conditioning devices.
Outdoors where charge limits do not apply, hydrocarbons are seen as suitable in systems up to 150kW and ammonia for capacities over 150kW. Popular in Europe, these refrigerants are seen as useful options for developing countries, particularly because both R290 and ammonia perform very well at high ambient temperatures over 40°C.
In the foam sector, hydrocarbon blowing agents have become standard in industrialised countries, and can replace HCFCs to a large extent in the manufacturing of PU foam and of XPS foam. HFOs like 1234ze and 1336mzz are also growing in use as blowing agents, particularly applications like PU spray foam for which highly flammable hydrocarbons are not deemed safe.
According to Öko-Recherche , approximately 13% of the refrigerant/blowing agent demand which is projected for 2030 will not be suitable for replacement by hydrocarbons and could be substituted by HFOs instead.
The report also acknowledges the use of HFOs in some chillers and, running contrary to other opinions in Germany, the potential benefits from the introduction of R1234yf in car air conditioning systems.
Now under a “death sentence” in Europe, the proliferation of R404A in developing countries, where refrigeration demand is expected to triple by 2030, is a major concern. In any case, according to the report, R404A shows poor performance at high ambient temperatures.
The report points to the preferred alternative options in Europe, specifically the highly efficient “two-stage” cascade systems with CO2 as heat transfer fluid for low temperature and R134a for medium temperature cooling.
“It can be further reduced at the upper stage when HFC/HFO blends or indirect hydrocarbon-based systems are commercially available at a feasible cost,” says the report.
The report finds challenges still to be overcome to find a replacement for condensing units with capacities greater than 5kW. “For the common technology of direct expansion a short term high efficient alternative to R22 with low or moderate GWP is not yet available,” it says.