Abstract
Carbon Dioxide, CO2, was one of the first commonly applied working fluids in the infancy of refrigeration
more than 100 years ago. In contrast to ammonia it mainly disappeared after the first generation of synthetic
refrigerants have been introduced to the market after 1930. One reason was that the transition from low-rpm
belt driven compressors towards the direct electrical motor driven compressors (50-60 Hz) was not
performed for CO2 compressors before the revival introduced by Gustav Lorentzen in the 90is of last
century. Since 1988 an enormous R & D effort has been made to further develop CO2 refrigeration
technology in spite of the opposition from the chemical industry.
Today CO2 refrigeration and heat pumping technologies are accepted as viable and sustainable alternatives
for several applications like commercial refrigeration, transport refrigeration, vehicle air conditioning & heat
pumping, domestic hot water heat pumps and industrial applications. For some applications the current
threshold to introduce CO2 technology can be overcome when the system design is taking into account and
advantage of the thermo dynamical- and fluid properties of CO2. I.a the system is designed for transcritical
operation with all it pros and cons and takes into consideration how to minimize the losses and to apply the
normally lost expansion work. Shortcut-designs, i.e. drop in solutions, just replacing the H(C)FC
refrigeration unit with an CO2 systems adapted for higher system pressures will not result in energy efficient
products. CO2 systems do offer the advantage of enabling flooded evaporators supported with adapted
ejector technology which offer high system performances at low temperature differences and low
temperature air mal-distributions across evaporators.
The paper gives an overview for the development possibilities for several applications during the next years
to further increase the market share of CO2 refrigeration and heat pump systems.
more than 100 years ago. In contrast to ammonia it mainly disappeared after the first generation of synthetic
refrigerants have been introduced to the market after 1930. One reason was that the transition from low-rpm
belt driven compressors towards the direct electrical motor driven compressors (50-60 Hz) was not
performed for CO2 compressors before the revival introduced by Gustav Lorentzen in the 90is of last
century. Since 1988 an enormous R & D effort has been made to further develop CO2 refrigeration
technology in spite of the opposition from the chemical industry.
Today CO2 refrigeration and heat pumping technologies are accepted as viable and sustainable alternatives
for several applications like commercial refrigeration, transport refrigeration, vehicle air conditioning & heat
pumping, domestic hot water heat pumps and industrial applications. For some applications the current
threshold to introduce CO2 technology can be overcome when the system design is taking into account and
advantage of the thermo dynamical- and fluid properties of CO2. I.a the system is designed for transcritical
operation with all it pros and cons and takes into consideration how to minimize the losses and to apply the
normally lost expansion work. Shortcut-designs, i.e. drop in solutions, just replacing the H(C)FC
refrigeration unit with an CO2 systems adapted for higher system pressures will not result in energy efficient
products. CO2 systems do offer the advantage of enabling flooded evaporators supported with adapted
ejector technology which offer high system performances at low temperature differences and low
temperature air mal-distributions across evaporators.
The paper gives an overview for the development possibilities for several applications during the next years
to further increase the market share of CO2 refrigeration and heat pump systems.