No abstract

Searching for new refrigerants is one of the most significant scientific problems in refrigeration. There are ecological refrigerants commonly known: H 2 O and CO 2 . H 2 O and CO 2 known as natural refrigerants, but they have problems:a high freezing point of H 2 O and a low triple point of CO 2 . These problems can be solved by the application of a hybrid sorption-compression refrigeration cycle. The cycle combines the application possibility of H 2 O in the high temperature sorption stage and the low temperature application of CO 2 in the compression stage. This solution gives significant energy savings in comparison with the two-stage compressor cycle and with the one-stage transcritical CO 2 cycle. Besides, the sorption cycle may be powered by low temperature waste heat or renewable heat. This is an original idea of the authors. In the paper an analysis of the possible extension of this solution for high capacity industrial refrigeration is presented. The estimated energy savings as well as TEWI (Total Equivalent Warming Impact) index for ecological gains are calculated.

No abstract

No abstract

No abstract

The requirements for environmentally friendly refrigerants promote application of CO2 and water as working fluids. However there are two problems related to that, namely high temperature limit for CO2 in condenser due to the low critical temperature, and low temperature limit for water being the result of high triple point temperature. This can be avoided by application of the hybrid adsorption-compression system, where water is the working fluid in the adsorption high temperature cycle used to cool down the CO2 compression cycle condenser. The adsorption process is powered with a low temperature renewable heat source as solar collectors or other waste heat source. The refrigeration system integrating adsorption and compression system has been designed and constructed in the Laboratory of Thermodynamics and Thermal Machine Measurements of Cracow University of Technology. The heat source for adsorption system consists of 16 tube tulbular collectors. The CO2 compression low temperature cycle is based on two parallel compressors with frequency inverter. Energy efficiency and TEWI of this hybrid system is quite promising in comparison with the compression only systems. Nomenclature GW P -global warming potential CO2 equivalent E -energy use of the cycle per year, kWh f -refrigerant recovery L -emission to the atmosphere, kg/yr m -amount of refrigerant in installation, kg n -cycle life, yr N -supplied electric power of the cycle, kW tr -yearly number of work hours, h z -CO2 emission for the electric energy; in Poland z = 0, 94 kgCO2/kWh

No abstract

No abstract