buletinul institutului politehnic din iaşi - Universitatea Tehnică ...

Bul. Inst. Polit. Iaşi, t. LVIII (LXII), f. 4, 2012 57
4. Conclusions
1. The evaporation heat content of R404a is significantly lower (90%
less) than the baseline R717 value, while that of R410a is slightly higher.
2. The COP cycle of R134a is about 17% lower than the baseline value,
indicating that this refrigerant does not match the baseline R407c cycle
performance. These characteristics imply that both R404a and R410a
refrigerants have weaker heat transfer ability and lower cooling capacity on
equal heat pump load base, as compared to R717.
3. Increased vapor density for R507, R410a and R404a may also lead to
the use of a smaller compressor and coil tubing that could result in less system
power consumption and more efficient component design.
4. Overall, however, a comparable COP system is possible for R404a, and
even a moderate system efficiency improvement might be expected for R410a
for a certain heat pump load.
5. The COP system is also influenced by compressor volumetric
efficiency, which is a function of compression ratio H (pcond/pevap) and
compressor isentropic efficiency, which could be affected by other transport
properties, as well as system design.
REFERENCES
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*** Livre blanc sur les fluides frigorigènes. Conseil National du Froid, Paris, AFF,
2001, 51 pages.
*** Report of the Technology and Economic Assessment Panel April 2000. UNEP.
2000, UNEP, Nairobi, 193 pages.
Harnisch J., Hendriks C., Economic Evaluation of Emission Reductions of HFCs. PFCs
and SF in Europe, Ecofys Energy and Environment, 2001.
Chang Y.S., Kim M.S., Ro S.T., Performance and Heat Transfer Characteristics of
Hydrocarbon Refrigerants in a Heat Pump System. International Journal of
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Pelletier O., Propaneas Refrigerant in Residential Heat Pumps. Licentiate thesis. Royal
Institute of Technology, Stockholm, Sweden, 1998.
METODA MULTICRITERIALĂ DE ALEGERE A AGENŢILOR FRIGORIFICI
PENTRU POMPELE TERMICE
Lucrarea propune o evaluare multicriterială pentru pompele termice care lucrează
cu agenţi frigorifici cu ODP zero (R600, R404a, R407c, R410a, R134a, R507, R134a şi
R717). Proprietăţilor termo-fizice ale agenţilor nu sunt suficiente pentru o evaluare
completă, iar o abordare multicriterială permite o apreciere completă. Parametrii