Where reciprocating refrigerant compressors excel Select the operating range for which reciprocating refrigerant compressors are most suitable.

Introduction / Context:
Compressor selection depends on flow rate and pressure ratio. Reciprocating (piston) compressors are positive displacement machines particularly suited to certain combinations of capacity and discharge pressure in refrigeration service.

Given Data / Assumptions:

• Comparing reciprocating machines with centrifugal/axial or screw compressors.
• Refrigeration applications requiring moderate to high condensing pressures.

Concept / Approach:
Reciprocating compressors handle small to moderate volumetric flows with high pressure ratios efficiently. They develop high discharge pressures at acceptable isentropic efficiencies in compact packages, making them ideal for small systems, low-temperature plants, and high head applications.

Step-by-Step Solution:
Identify capacity range: small displacement volumes per unit time.Identify pressure range: capable of high condensing pressures and large pressure ratios.Thus, the best fit is “small displacements and high condensing pressures.”

Verification / Alternative check:
Industry practice uses reciprocating units for small cold rooms, freezers, and laboratory refrigeration, while centrifugal/screw units dominate high-flow, lower pressure-ratio HVAC chillers.

Why Other Options Are Wrong:
(a) Low condensing pressures do not require the strengths of reciprocating compressors. (b) Large displacements are better handled by rotary or dynamic machines. (d) Same issue as (a). (e) Very large flows with low ratios are the domain of centrifugal/axial machines.

Common Pitfalls:
Assuming “bigger is always better”; machine type must match both flow and head requirements.

Final Answer:
small displacements and high condensing pressures