Thermodynamics, Energy & Mechanics

Both statements correctly describe the Vapour Compression Refrigeration System (VCRS):

• Statement (I) is true: The mechanical compressor draws low-pressure, low-temperature superheated vapor from the evaporator and compresses it isentropically to a high-pressure, superheated high-temperature vapor so that its saturation temperature exceeds the temperature of the available cooling medium (air or water).
• Statement (II) is true: In the condenser, the high-pressure refrigerant vapor rejects its latent heat of condensation to the surrounding ambient medium and condenses into high-pressure saturated liquid.

In psychrometrics and air conditioning:
Sensible heating is the process of increasing the dry bulb temperature of air without any addition or removal of moisture. Therefore, the specific humidity / humidity ratio (\(w\)) remains strictly constant, while relative humidity (\(RH\)) actually decreases. Thus, Assertion (A) is completely false.
On a standard psychrometric chart (with dry-bulb temperature on the horizontal x-axis and specific humidity on the vertical y-axis), sensible heating proceeds horizontally from left to right at constant \(w\), forming a straight horizontal line. Thus, Reason (R) is true.

Refrigeration capacity conversion:

• Heat removal rate:
  \[ Q = 2500\text{ cal/s} = 2.5\text{ kcal/s} \]
  In terms of kilocalories per minute:
  \[ Q = 2.5\text{ kcal/s} \times 60\text{ s/min} = 150\text{ kcal/min} \]
• Definition of One Ton of Refrigeration (TR):
  • One TR is the rate of heat removal required to freeze 1 short ton (2000 lb) of water at 0°C into ice at 0°C in 24 hours.

• In metric engineering units:

• Capacity of the refrigeration system:
  \[ \text{Capacity} = \frac{150\text{ kcal/min}}{50\text{ kcal/min per TR}} = 3\text{ TR} \]