With increasing energy price and concern on environmental impacts, more attention has been paid

to refrigeration and heat pump systems. Several regulations have already been applied on the choice

of refrigerants and the search for more energy efficient system solutions has been intensified. Due

since 1990s.

transcritical cycle, which means part of the cycle is located in supercritical region, where the

optimum gas cooler pressure for every heat sink temperature. Moreover, depending on the heat sink

refrigeration cycles.

A new CO2 refrigeration/heat pump test rig is built at the div. of Applied Thermodynamics andRefrigeration to investigate CO

can perform comprehensive testing for

• Investigating the heat recovery process of a CO2 refrigeration/heat pump systems

• Component testing (heat exchangers, compressors, etc.)

• Control algorithm investigation

• System performance evaluation

After the thesis work, the student should be able to

research interest in the field of CO2 heat pump

• Get the knowledge of different measurements: temperature, pressure, mass flow

results.

including following main tasks:

2

testing and theoretical analysis

CO2 and heating up process of water, based on different operating conditions

• Basic components testing, namely the heat exchangers and the compressor

• Testing the operating conditions at optimum COP and optimum cooling capacities

Obama's offer reflects numbers in a bill narrowly passed by the House of Representatives in June but yet to be confirmed by the Senate.A slightly more ambitious bill to come before the Senate early next year talks of a 20 percent reduction from 2005 levels by 2020.Copenhagen climate change talks stall as CO2 emissions rise - Christian Science Monitor jeudi, novembre 19, 2009, 09:15 AM - Développement durableThe Copenhagen summit on climate change is looking less likely to produce a binding CO2 emissions reduction agreement as a new study finds that global carbon dioxide emissions increased 29 percent in the past nine years.

Meanwhile, The Global Carbon Project, an international group of climate scientists, released research on Tuesday that found carbon-dioxide (CO2) emissions from power plants, factories, tree-felling and other human activities grew by 29 percent between 2000 and 2008 –a period in which leaders of major industrialized nations took the first fledgling steps to reduce their own emissions and make an international climate treaty work.

The Kyoto Protocol on combating climate change was passed in 1997 by over 180 nations with the intent of reducing global carbon emissions to a 1990 baseline. But in the intervening 12 years emissions have continued to rise, as country's have been unwilling to take the economic hits that reduced emissions are likely to require.Political leaders are now looking to the US and President Barack Obama to take the lead on climate change, since the US is the second-largest carbon emitter after China.

But legislation to curb US emissions is currently stalled in Congress, a factor that also makes broad success in Copenhagen less likely. Also uncertain is aid from the developed world to help poorer countries offset the economic hardships of converting to cleaner power sources."We still need more movement," said UN Climate Change head Yvo de Boer in Denmark on Tuesday. "Industrialized countries must raise their targets and financial commitments further... I look to the United States for a numerical mid-term target."In recent weeks leaders in key countries have signalled that no one should look for a treaty to be approved in Copenhagen next month – a clear hope coming out of global climate talks in Bali in December 2007.

On Sunday Denmark's Prime Minister Lars Lokke Rasmussen suggested that countries aim for a more limited political agreement on reducing emissions and building a financial-aid regime for developing countries, with a legally-binding treaty put off until high-level talks in December 2010 in Mexico City. The UN's Mr. de Boer has said he prefers to see a legal document ready for approval in Bonn sometime in mid-2010.

Emissions up in recessionDespite the global economic slowdown last year, emissions rose 2 percent in 2008. The Global Carbon Project estimates that 2009's deep economic contraction trimmed global emissions by nearly 3 percent, but that short term dip is expected to reverse once recovery takes hold.Noting that population growth and efforts to improve the standard of living in developing countries are among the underlying forces driving rising emissions, the need to cut CO2 emissions "is a very urgent task," says Taro Takahashi, a researcher at Columbia University's Lamont-Doherty Earth Observatory and one of the study's authors.

The question mark looming over the Copenhagen meeting has been the willingness of industrial nations to cap the increase in global average temperatures to 2 degrees Celsius (3.6 degrees Fahrenheit) above pre-industrial levels.To stand an even chance of achieving that, countries should aim to stabilize atmospheric CO2 concentrations at between 350 and 400 parts per million, according to the Intergovernmental Panel on Climate Change.

The Global Carbon Project's latest figures show that CO2 concentration levels have risen to 385 parts per million.Moreover, the team estimates that where changes in land use, largely deforestation, accounted for 20 percent of human emissions between 1990 and 2000, that figure has fallen to about 12 percent for the 2000 to 2008 period.

The emissions update appears in this week's issue of the journal Nature Geophysics.Remaining uncertaintyNo single study represents the final word on what's happening with carbon emissions. And the team acknowledges that more work needs to be done to cope with uncertainties. One key issue involves divvying up the uptake and release of CO2 among the various natural sources and "sinks." The study indicates that forests and oceans took up less CO2 during the 2000-2008 period than they did during the previous decade. They attribute the change to global warming and natural climate swings.

Other researchers, however, point out that their work shows no change in the ability of these sinks to soak up CO2.Still, because the Global Carbon Project was established to help inform political decisions on climate policies, its conclusions are likely to carry weight as negotiators grope their way toward a new climate treaty.

The list of outstanding issues is long, according to Jennifer Morgan, who heads the climate and energy program at the World Resources Institute in Washington. Convincing developed countries to make substantial emissions reductiover 180 nations with the intent of reducing global carbon emissions to a 1990 baseline. But in the intervening 12 years emissions have continued to rise, as country's have been unwilling to take the economic hits that reduced emissions are likely to require.Political leaders are now looking to the US and President Barack Obama to take the lead on climate change, since the US is the second-largest carbon emitter after China. But legislation to curb US emissions is currently stalled in Congress, a factor that also makes broad success in Copenhagen less likely. Also uncertain is aid from the developed world to help poorer countries offset the economic hardships of converting to cleaner power sources."We still need more movement," said UN Climate Change head Yvo de Boer in Denmark on Tuesday. "Industrialized countries must raise their targets and financial commitments further...

I look to the United States for a numerical mid-term target."In recent weeks leaders in key countries have signalled that no one should look for a treaty to be approved in Copenhagen next month – a clear hope coming out of global climate talks in Bali in December 2007.On Sunday Denmark's Prime Minister Lars Lokke Rasmussen suggested that countries aim for a more limited political agreement on reducing emissions and building a financial-aid regime for developing countries, with a legally-binding treaty put off until high-level talks in December 2010 in Mexico City.

The UN's Mr. de Boer has said he prefers to see a legal document ready for approval in Bonn sometime in mid-2010.

Emissions up in recessionDespite the global economic slowdown last year, emissions rose 2 percent in 2008. The Global Carbon Project estimates that 2009's deep economic contraction trimmed global emissions by nearly 3 percent, but that short term dip is expected to reverse once recovery takes hold.Noting that population growth and efforts to improve the standard of living in developing countries are among the underlying forces driving rising emissions, the need to cut CO2 emissions "is a very urgent task," says Taro Takahashi, a researcher at Columbia University's Lamont-Doherty Earth Observatory and one of the study's authors.

The question mark looming over the Copenhagen meeting has been the willingness of industrial nations to cap the increase in global average temperatures to 2 degrees Celsius (3.6 degrees Fahrenheit) above pre-industrial levels.To stand an even chance of achieving that, countries should aim to stabilize atmospheric CO2 concentrations at between 350 and 400 parts per million, according to the Intergovernmental Panel on Climate Change.

The Global Carbon Project's latest figures show that CO2 concentration levels have risen to 385 parts per million.Moreover, the team estimates that where changes in land use, largely deforestation, accounted for 20 percent of human emissions between 1990 and 2000, that figure has fallen to about 12 percent for the 2000 to 2008 period. The emissions update appears in this week's issue of the journal Nature Geophysics.

Remaining uncertainty.

No single study represents the final word on what's happening with carbon emissions. And the team acknowledges that more work needs to be done to cope with uncertainties. One key issue involves divvying up the uptake and release ofCO2 among the various natural sources and "sinks." The study indicates that forests and oceans took up less CO2 during the 2000-2008 period than they did during the previous decade.

They attribute the change to global warming and natural climate swings. Other researchers, however, point out that their work shows no change in the ability of these sinks to soak up CO2.Still, because the Global Carbon Project was established to help inform political decisions on climate policies, its conclusions are likely to carry weight as negotiators grope their way toward a new climate treaty.The list of outstanding issues is long, according to Jennifer Morgan, who heads the climate and energy program at the World Resources Institute in Washington. Convincing developed countries to make substantial emissions reduction is just one challenge.

Convincing major developing countries to slow and eventually reverse their emissions trends is another, as is the need to provide financial aid to poorer countries to buy the technology needed to achieve goals they agree to.

Finally, finding a monitoring regime and legal status for enforcement that all countries will accept won't be easy,"All the major economies coming to Copenhagen are coming ready to fill in those blanks," says Ms. Morgan. These countries are looking for "what the [Obama] administration is able to bring to the table consistent with what Congress is debating" in energy and climate bills it's currently considering.Yet President Obama, during a summit with Chinese leaders this week, noted that "our aim ... is not a partial accord or a political declaration, but rather an accord that covers all of the issues in the negotiations and one that has immediate operational effect."Some analysts who have been watching this process since the Kyoto Protocol was hammered out still say much can be accomplished at Copenhagen, even if the result falls short of a legally binding agreement for now.

"A few months before Kyoto, people were throwing up their hands saying nothing could happen. A month before Rio, in the final negotiating session, it was unclear there would be the political will to move an agreement forward for the heads of state," says Alden Meyer, director of strategy and policy for the Union of Concerned Scientists in Washington. "Some of us have seen this movie before.

Expectations are high and they should be kept high."WASHINGTON (Reuters) - The Environmental Protection Agency on Monday cleared the way for regulation of greenhouse gases without new laws passed by Congress, reflecting President Barack Obama's commitment to act on climate change as a major summit opened in Copenhagen.

The EPA ruling that greenhouse gases endanger human health, widely expected after it issued a preliminary finding earlier this year, will allow the agency to regulate planet-warming gases even without legislation in Congress.The agency could begin to make rules as soon as next year to regulate emissions from vehicle tailpipes, power utilities and heavy industry under existing laws.Obama and his Democratic allies in Congress will still pursue legislation in Congress, which has been slow to act. But the EPA move gave a timely push to the president's aims of securing short-term limits to harmful emissions.It was expected to inject some optimism into the two-week United Nations meeting in Copenhagen, which Obama is due to attend next week, but was criticized by some U.S. business groups who fear it could push up costs.

"EPA has finalized its endangerment finding on greenhouse gas pollution and is now authorized and obligated to make reasonable efforts to reduce greenhouse pollutants," said Lisa Jackson, the EPA administrator. "This administration will not ignore science or the law any longer.

"The Supreme Court ruled in 2007 that the EPA had the right to regulate emissions of the gases under the Clean Air Act. But under the administration of former President George W. Bush, the EPA said Congress was the right place to frame action.Business groups said the EPA announcement would hurt the economy and endanger jobs just as the country emerges from a deep recession.Legislation by Congress would be more palatable politically for Obama, because it would represent a compromise between business, politicians and other interests rather than through an imposed ruling.

STRONGER HAND IN COPENHAGEN 

The EPA ruling applies to six gases scientists say contribute to global warming, including the main one, carbon dioxide.There had been fears that Obama, who has made fighting climate change one of his priorities, would arrive almost empty handed at the U.N. conference because climate legislation has stalled in Congress."The EPA move strengthens Obama's hand at Copenhagen," said Joe Mendelson, global warming policy director at the National Wildlife Federation. "It gives him additional authority that if Congress doesn't pass climate legislation, the agency can put the country on the path to meet his climate goals."Obama will pledge at Copenhagen that the United States, the world's second largest emitter of greenhouse gases, will cut emissions by roughly 17 percent by 2020 from 2005 levels.

World leaders hope to reach an agreement at the meeting on getting rich and developing countries to share the burden in fighting climate change.The climate bill has been delayed in the U.S. Senate by a debate over a sweeping reform of healthcare, but lawmakers hope to pass a bill in the spring.

Climate legislation passed narrowly in the House of Representatives in June.The Obama administration has always said it prefers legislation over action by the EPA.CONGRESSIONAL ACTIONIf the EPA acts alone it could face a slew of legal challenges, including from business groups who say the action would overstep the administration's authority, as well as from environmentalists who seek stronger steps.

But the administration had pressed the EPA to prod business to support efforts in Congress, and to show the world Washington is committed to fighting climate change.Democratic Senator John Kerry said the EPA move was meant to spur Congress to act. But he said "imposed regulations by definition will not include the job protections and investment incentives we are proposing in the Senate today."Republicans said the move was equivalent to imposing an energy tax. "By seeking to sharply curtail carbon dioxide (and thus energy usage), the EPA is in effect working to decrease economic activity," the Republican Study Committee said.

One business group was quick to criticize the EPA.Keith McCoy, vice president of energy policy at the National Association of Manufacturers said the EPA was moving forward with an agenda that will put additional burdens on manufacturers, cost jobs and drive up the price of energy.

"The EPA decision, which now will be open for public review, does not preclude legislation. Any new regulations could take a long time to implement, giving Congress room to act.Still, big industry could learn about changes soon. Jackson said car makers will know by the end of March about required increases in fuel economy standards for cars built for the 2012 model year.

"All industries will be called upon to reduce carbon emissions," said Dave McCurdy, chief executive of the Alliance of Automobile Manufacturers.An administration proposal unveiled in September would require a boost fuel efficiency by 40 percent by 2016 and aim to cut carbon emissions by 21 percent by 2030.

(Additional reporting by Ayesha Rascoe, Roberta Rampton, Deborah Zabarenko, Tom Doggett, Tom Ferraro in Washington and Richard Cowan in Copenhagen; Editing by Simon Denyer and Chris Wilson)

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