1. What is Heat Rejection?

Heat rejection refers to the total amount of heat that must be removed from a refrigeration or air conditioning system. It represents the sum of the heat absorbed from the cooled space (refrigeration capacity) plus the heat generated by the compressor work input.

2. How Does the Calculator Work?

The calculator uses the fundamental thermodynamic equation:

Where:

• \( \text{Compressor Work} \) — Electrical power input to the compressor (W)
• \( \text{Refrigeration Capacity} \) — Cooling capacity or heat absorption rate (W)
• \( \text{Heat Rejection} \) — Total heat rejected to the condenser (W)

Explanation: This equation is based on the first law of thermodynamics applied to refrigeration cycles, where all energy inputs and heat transfers must balance.

3. Importance of Heat Rejection Calculation

Details: Accurate heat rejection calculation is crucial for proper condenser sizing, cooling tower selection, and overall system design. It ensures efficient heat dissipation and prevents system overheating.

4. Using the Calculator

Tips: Enter compressor work and refrigeration capacity in watts (W). Both values must be non-negative. The calculator will compute the total heat rejection that must be handled by the condenser.

5. Frequently Asked Questions (FAQ)

Q1: Why is heat rejection greater than refrigeration capacity?
A: Because heat rejection includes both the heat removed from the cooled space and the additional heat generated by compressor work.

Q2: What units should I use for this calculation?
A: Watts (W) are recommended, but any consistent power unit (kW, BTU/hr) can be used as long as both inputs use the same unit.

Q3: How does COP relate to heat rejection?
A: COP = Refrigeration Capacity / Compressor Work. Heat Rejection = Refrigeration Capacity × (1 + 1/COP).

Q4: What affects heat rejection in real systems?
A: Compressor efficiency, refrigerant properties, operating temperatures, and system losses all influence actual heat rejection.

Q5: How is this used in system design?
A: Heat rejection values determine condenser size, cooling water requirements, and heat exchanger specifications for proper system operation.