Which of the following statements about refrigeration are TRUE and which are FALSE?

Here are the answers to the statements, indicating whether each is TRUE or FALSE: i. Cooling of a hot cup of coffee by leaving it on a table is refrigeration. FALSE. Refrigeration typically refers to maintaining a temperature below* the ambient temperature. Cooling to ambient is simply heat transfer. ii. One of the disadvantages of natural refrigeration methods is that they are uncertain. TRUE. Natural methods are often dependent on environmental conditions, making their performance less predictable. iii. Throttling loss decreases as the evaporator temperature decreases. FALSE. As evaporator temperature decreases, the pressure ratio across the throttling valve generally increases, leading to increased* irreversibility and throttling loss. iv. In vapour compression refrigeration, isothermal heat rejection is replaced by isenthalpic throttling. FALSE. Isenthalpic throttling replaces the isentropic expansion process of an ideal cycle, not the isothermal heat rejection. v. The COP of Carnot refrigeration is always lower than the COP of vapour compression refrigeration system. FALSE. The Carnot COP is the maximum possible COP; actual vapor compression systems have a COP lower than or equal to* the Carnot COP. vi. Superheating increases both the work input and refrigeration effect. TRUE. Superheating increases the enthalpy at the compressor inlet (h_1), which increases both the refrigeration effect (h_1 - h_4) and the compressor work (h_2 - h_1). vii. The higher the volumetric flow rate, the lower the capacity of the compressor. TRUE. If "volumetric flow rate" refers to the specific volume of the refrigerant at the compressor inlet, a higher specific volume means a lower mass flow rate for a given compressor displacement, thus reducing the refrigeration capacity. viii. At low evaporator temperature, effect of condensing temperature is very high. TRUE. The COP is more sensitive to changes in condensing temperature when the evaporator temperature is low. ix. In actual system, the temperature of the heat sink will be several degrees higher than the condensing temperature for heat transfer to take place. FALSE. For heat to be rejected, the condensing temperature must be higher* than the heat sink temperature. x. A system with subcooling, the vapour fraction at the inlet evaporator is reduced. TRUE. Subcooling reduces the enthalpy of the liquid entering the expansion valve, which in turn reduces the amount of flash gas (vapor fraction) at the evaporator inlet. xi. During sensible heating, the enthalpy increases. TRUE. Sensible heating increases the temperature of a substance without phase change, which directly increases its enthalpy. xii. Useful superheating increase refrigeration effect and decrease work of compression. FALSE. Useful superheating increases both the refrigeration effect and the work of compression. xiii. For the same system, degree of superheating is lower than degree of subcooling. FALSE. There is no general rule; the degrees of superheating and subcooling depend on the specific system design and operating conditions. xiv. A SHF of 1.0 implies a pure sensible heat transfer. TRUE. Sensible Heat Factor (SHF) of 1.0 means that the latent heat transfer is zero, indicating only sensible heat transfer. xv. During sensible cooling of air, both dry bulb and wet bulb temperatures decrease. TRUE. Sensible cooling lowers the dry bulb temperature. If no dehumidification occurs, the wet bulb temperature will also decrease. xvi. In zone of vaso-motor regulation against cold, blood vessels adjacent to skin dilate. FALSE. Against cold, vasoconstriction* occurs to reduce blood flow to the skin and conserve heat. Vasodilation occurs in