What technology is currently used?
Cold generators which are used today in existing refrigeration and air-conditioning systems, operate on vapor compression, absorption and evaporative principles. This technology was developed at the beginning of 1900x and have not changed since.
Disadvantages of such cooling devices include:
Evaporation: low efficiency, dependence on humidity of ambient air;
Vapor compression: the use of an intermediate working fluid - refrigerant and significant emissions of thermal energy into the atmosphere;
Vortex: low efficiency, thermal emissions to the atmosphere.
Different types of refrigerants have been used in air conditioners over the years. The discovery that chlorofluorocarbons (CFCs) are major contributors to ozone-layer breakdown prompted an international response that led to the creation of the Montreal Protocol on Substances that Deplete the Ozone Layer, which went into effect in 1989 and eventually eliminated production of CFCs in 1996. The CFCs were replaced by hydrochlorofluorocarbons (HCFCs), a transitional fluorocarbon with a reduced impact on ozone depletion to be used only while companies developed better coolants. Today these replacements are, themselves, being phased out and replaced by hydrofluorocarbons(HFCs).
HFCs have no impact on ozone depletion because they lack chlorine. However, they have been found to possess a characteristic that is not covered by the Montreal Protocol: They are super-greenhouse gases with high potential to contribute heavily to global warming. The effort to solve one environmental problem, therefore, is likely exacerbating another. Hydrofluorocarbons (HFCs) are a group of organic compounds that contain carbon, fluorine, and hydrogen. They are by-products of industrial manufacturing and were introduced as a replacements for chlorofluorocarbons and other ozone-depleting substances. However, though HFCs have zero ozone depletion potential (ODP), they have intrinsic and significant global warming potential (GWP), typically in the range of 1,000 to 3,000 times that of CO2. Thus, they are among the six key greenhouse gases listed in the Kyoto Protocol for emission reduction. Other greenhouse gases listed by the protocol are CO2, CH4, N2O, PFCs,
SF6, and HFCs.
Cold is still overwhelmingly produced by burning fossil fuels.27% of all global warming will be due to the gases emitted from air conditioning by the year 2050. *
*) According to the National Institute for Public Health and the Environment of the Netherlands.
Current technology uses hydrofluorocarbons that absorb and release heat – plus large amounts of electricity. HFCs and other refrigerants cooling systems produce greenhouse gases that can be up to 4,000 times more harmful than CO2.
Emission targets agreed at international climate summits are already very tight, using old technology is not an answer for an increasing demand of air-conditioning and refrigeration
Currently used cooling technology is obsolete.
Some refrigeration units are far more harmful.
According to a report by the energy consultancy E4tech, the small diesel-powered fridges on food trailers emit nearly 30x times more harmful particulate matter and six times more nitrogen oxides than the engine that powers the trucks.
That matters, because the world needs an awful lot more refrigerated food trailers. With the world’s population forecast to reach 9 billion by 2050, cold’s role in food security will be key.
According to the UN Food and Agriculture Organisation, global food demand is set to grow by 50% in that time.