R290

A 0.5 deg. C of global warming (by 2100) can be prevented with the phase-down of HFCs; contributing to numerous environmental and economic benefits. Phasing out HFCs under the Montreal Project is by far the most significant, cost-effective and practicable measure required to limit a global average temperatures rising 2°C back to pre-industrial average temperatures. World leaders agreed to that level during the 2010 United Nations Framework Convention on Climate Change (UNFCCC) in Cancun, Mexico.

To date, 197 countries have signed on to the Montreal Protocol, making it the only universally ratified UN treaty.

Following the Montreal Protocol agreement on the phase-out of Ozone Depletion Substances (ODSs) and subsequent success in achieving its targets on CO2 emission reduction to date, the Montreal Protocol has been successfully generating further efforts to phase down HFCs through its members’ body; relaying the tremendous credibility and sway on global markets.

The increased popularity of HFCs (replacement to CFCs) has produced a further challenging problem for the Montreal Protocol. Although safe for the ozone layer, the continued emissions of HFCs – primarily as alternatives to the ODS will have an immediate and significant effect on the Earth’s climate system. Without further controls, it is predicted that HFC emissions could negate the entire climate benefits achieved under the Montreal Protocol.

HFCs are rapidly increasing in the atmosphere!

The Montreal Protocol Body are advised by experts on ODS’s as well as providing advice on HFCs. This advisory group for the Technology and Economic Assessment Panel (TEAP), comprised of experts from government agencies, universities and non-government organisations universally. They provide internationally respected research on scientific, environmental, economic and technological issues requested by parties to the Montreal protocol.

Since HFCs entered the market in the 1990s, TEAP has issued annual recommendations on the usage and impacts of HFCs – making the panel well-equipped to advise the international community on their usage, examine the efficiency, cost-effectiveness and barriers of low-GWP HFC alternatives.

Right from the outset, the Montreal Protocol has established that developed countries would lead the phase-down of HFCs, and developing countries would begin their phase-down at a later date. The later start date for developing countries would allow more time for the development of affordable and reliable alternatives. Consequently this leaves developed countries with no other choice but to take on responsibility by keeping the phase-down momentum in place.

The impetus has steadily grown for phasing down HFCs. Some key recent events have supported this growing momentum:

• More than 100 countries have signed in support of the transition to low-GWP alternatives to ODSs
• Rio+20 world leaders unanimously agreed to support a gradual phase-down in HFC consumption and production in June 2012
• The Climate and Clean Air Coalition (33 countries and the European Union) adopted a HFC phase-down under the Montreal Protocol in 2013
• The Arctic Council urged the Montreal Protocol to phase down HFC consumption and production as soon as possible in its final declaration during mid-2013
• USA President Barack Obama and Chinese President XI Jinping agreed to use the institutions and expertise of the Montreal Protocol to phase down HFCs consumption and production during a presidential 2013 summit
• The private sector is committed and leading the reduction of HFCs usage, in line with The Consumer Goods Forum’s November 2010 pledging to begin phasing out HFCs within new systems from 2015

As environmental law and regulations are set to continue tightening, the impetus is growing to identify an alternative to the popular HFC refrigerant currently used in most refrigeration systems. A limited number of HFCs are currently available as refrigerants used within water chillers, inevitably CO2, ammonia and hydrocarbon are destined to become the leading mainstream replacements.

These three refrigerant options are cost-effective, efficient alternatives to HFCs and are perfectly safe for the environment, however the Hydrocarbon R290 has the edge!

The Montreal Protocol:

“Perhaps the single most successful international agreement to date.” – According to former UN Secretary-General Kofi Annan

CFCs Impact on the Ozone Layer

The chlorofluorocarbon (CFC) phase-out was an important turning point in the recovery of the Ozone layer. At present, the depletion process is approximately 3 percent at Northern Hemisphere mid-latitudes and 6 percent at Southern Hemisphere mid-latitudes, but if no action had been taken to limit CFCs, the Ozone depletion process would eventually have reached 20 percent or more.

Thanks to the phase-out, CFCs are no longer accumulating in the atmosphere at an accelerating rate. CFC-11 and CFC-113 levels are decreasing, and CFC-12 levels are increasing but at a slower rate than in the past. If international agreements are adhered to, the Ozone layer is expected to recover around 2050.

HFCs Impact on the Ozone Layer

HFCs are fluorinated greenhouse gases introduced as replacements for Ozone-depleting substances such as CFCs. HFCs are used in wide and varied applications, as a direct replacement to CFCs.

Domestic and commercial air-conditioning, alongside many industrial applications, are taking by far the biggest portion of the users of HFCs. HFCs are also used in air-conditioning in vehicles plus smaller amounts are used in foam products, aerosols, solvents and fire protection systems.

Although HFCs are regarded to be less damaging than the CFCs, the HFCs are considered to be an intermediate substance. Most HFCs are still impacting on the global environment, although with less ferocity their warning impact is very strong. CFCs emissions are projected to increase nearly twenty-fold in the coming decades.

• R290 Refrigerant has excellent thermodynamic properties, leading to high energy efficiency
• Hydrocarbon Chillers operate as good as, or better than HFC based chillers in most applications
• Good compatibility with components and lubricants
• The refrigerant properties of hydrocarbons, such as pressures, pressure ratios and discharge temperatures are quite similar to those HFCs chillers in many respects
• Lower refrigerant charge, allowing smaller heat exchangers and piping dimensions

Ammonia NH2 as a Refrigerant

• Ammonia is a more efficient refrigerant than HFCs, so an ammonia based system requires less electricity, resulting in lower operating costs
• Ammonia is safe for the environment, with an Ozone Depletion Potential (ODP) rating of 0 and a Global Warming Potential (GWP) rating of 0
• Ammonia is substantially less expensive than HFCs

CO2 as a Refrigerant

• CO2 chillers deliver very high performance. However the efficiency of CO2 refrigerant depends more on the application and the climate than with other refrigerants as there is a decline in system efficiency with increasing condensing temperatures, and CO2 is among the refrigerants with the steepest drop in efficiency curve

Ammonia (R717) Refrigerant – Drawback

There are some disadvantages with using an ammonia as a refrigerant within water chillers:

• Ammonia (R717) chillers require a significantly higher maintenance intervention, hence higher on-going operational costs in comparison to Hydrocarbon chillers. Periodic, extensive overhaul is required to ensure the correct functionality of the system
• A second major maintenance issue is that in low temperature plants, the “low side” or “cold side” of the system operates at pressures below atmospheric. This means that minor leaks that develop around the valve stems pull air and moisture into the system. The air requires a special purging operation
• Moisture presence within filtration in ammonia systems can prove to be problematic, this requires special attention and equipment to remove
• Ammonia is poisonous in high concentrations. Two factors, however, mitigate the risk: Ammonia’s distinctive smell is detectable at concentrations well below those considered to be dangerous, and ammonia is lighter than air, so if any does leak, it will rise and dissipate in the atmosphere
• Compatibility with structural materials: whereas the use of R290 is fully compatible with most common metals (with the exception of zinc), ammonia (in presence of water traces) is aggressive on copper, zinc and their alloys. Therefore, iron is the only suitable material for plants using ammonia. In large centralised plants this restriction has limited importance
• Final adiabatic compression temperature: ammonia (R717) has a final adiabatic compression temperature much higher than hydrocarbon R290. The higher discharge temperature in general brings about high values of defects of efficiency due to de-superheating. Moreover, superheating losses are not compensated by the opposite trend of the throttling losses and with reciprocating compressors

CO2 Refrigerant – Drawback

CO2 is a high-pressure refrigerant that operates in high operating pressures to achieve efficient operation. During idle periods, the ambient temperature is likely to reach and exceed the critical temperature and the pressure may breech the critical pressure point, therefore CO2 systems are typically designed to withstand pressure up to 90 bar. The liquid density of CO2 is larger, resulting in higher mass charge in evaporators, consequently this may be forcing larger dimension chillers in particular with large industrial systems. Higher density means higher oil circulation, this in turn requires effective oil separators for industrial systems.

What about safety concerns with R290?

Hydrocarbon (R290) single blend refrigerant has different chemical properties compared to fluorocarbon refrigerants.

The primary difference is their classification as extremely flammable, therefore the handling and use of hydrocarbons requires adequate safety measures, thanks to our innovative design and by using an advanced technology every safety measure is taken by way of separation of the electrical compartment from the refrigeration and the mechanical section, the reduced charge of refrigerant per circuit  as well as using leakage detection module to eliminate any potential hazardous situation, ensuring utmost safety utilisation.