Optimization and thermodynamic performance measures for a class of finite time thermodynamic cycles

Thesis/Dissertation · Mon Jan 01 04:00:00 EST 1990

OSTI ID:5232722

Walters, J D

Modifications to the quasistatic Carnot cycle are developed in order to formulate improved theoretical bounds on the thermal efficiency of certain refrigeration cycles that produce finite cooling power. The modified refrigeration cycle is based on the idealized endoreversible finite time cycle. Two of the four cycle branches are reversible adiabats, and the other two are the high and low temperature branches along which finite heat fluxes couple the refrigeration cycle with external heat reservoirs. This finite time model was used to obtain the following results: (1) The performance of a finite time Carnot refrigeration cycle (FTCRC) is examined; (2) A finite time refrigeration cycle (FTRC) is optimized to obtain four distinct optimal cycling modes that maximize efficiency and cooling power, and minimize power consumption and irreversible entropy production; and (3) The problem of imperfect heat switches linking the working fluid of an FTRC to external heat reservoirs is studied. The maximum efficiency cycling mode is obtained by numerically optimizing the FTRC. Two distinct optimum cycling conditions exist: operation at the global maximum in efficiency; and operation at the frequency of maximum cooling power.

• Research Organization: Portland State Univ., OR (United States)
• OSTI ID: 5232722
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
425000* -- Engineering-- Power Cycles-- (1980-)
CARNOT CYCLE
CONVERSION
COOLING
EFFICIENCY
ENERGY CONSUMPTION
ENERGY CONVERSION
ENTROPY
FLUIDS
HEAT FLUX
HIGH TEMPERATURE
LOW TEMPERATURE
OPTIMIZATION
PHYSICAL PROPERTIES
REFRIGERATION
THERMODYNAMIC CYCLES
THERMODYNAMIC PROPERTIES
THERMODYNAMICS
WORKING FLUIDS