On the other hand, the necessary increase in condensation pressure to produce the higher subcooling produces a decrease in the COP.
Low subcooling is obtained with an almost undetectable increase in condensation pressure, this leading to an effective increase in COP.
2008, 2009), and do not cover flow condensation pressure drop characteristics.
These studies show that flow condensation pressure drop characteristics of refrigerant-oil mixtures are affected by the properties of refrigerant-oil mixtures.
Whereas in the case of conventional A/Cs, the condensation pressure remained almost the same when the outdoor temperature dropped lower than about 15[degrees]C (59[degrees]F), the new A/C can be operated even when the condensation pressure is reduced further, even with outdoor temperatures common in winter months (Figure 3).
Furthermore, reducing the condensation pressure increases specific enthalpy for the refrigerant in the evaporator (Figure 4).
In the case of conventional A/Cs, the pressure ratio is high, and the compressor consumes large volumes of power, but the new A/C can operate at low condensation pressures, so the pressure ratio is lower, and the compressor's power consumption can be reduced.
The cycle's behavior with EEV has been simulated by using a lower superheating (Table 1) and a lower condensation pressure than TEV.
This result agrees with previous works, (6,7) where a high energy savings was claimed (due to the great modulation and adjustment capability of EEV with respect to TEV) at low condensation pressure (that implies low outside air temperature), while energy saving is decreasing with the increasing of condensation temperature.
In the reversed Rankine cycle the compressor outlet pressure is dictated by the condensation pressure
corresponding to the condenser temperature.
Because of the absence of vacuum-pump oil, the condensation pressures of vapors passing through a chemical scroll pump are much higher than in an oil-sealed rotary vane pump (OSRVP).
As discussed earlier, due to the absence of pump oil and lubrication greases, the condensation pressures of solvents in chemical scroll pumps are a few orders of magnitude higher than those in OSRVPs.