A two stage cascade vapor compression refrigeration system uses ammonia in the low temperature loop and R-12 in the high-temperature loop. The ammonia provides 15 tons of cooling. If the high-loop temperature requires 10.12 kW compressor power and low loop 15.93 kW, determine the COP of the system.

A regenerative gas turbine power plant is
shown in Fig. P1. Air enters the compressor at 1
bar, 27ºC with a mass flow rate of 0.562 kg/s and
is compressed to 4 bar. The isentropic efficiency of
the compressor is 80%, and the regenerator
effectiveness is 90%. All the power developed by
the high-pressure turbine is used to run the
compressor. The low-pressure turbine provides the
net power output. Each turbine has an isentropic
efficiency of 87% and the temperature at the inlet
to the high-pressure turbine is 1200 K. Sketch the
corresponding T – s diagram and determine: (a) The net power output, in kW. (b) The thermal
efficiency. (c) The temperature of the air at states
2, 3, 5, 6, and 7, in K. 

At the beginning of the compression process of an air standard otto cycle. P1= 1 bar, T1= 290k and V1= 400cm^3. The max Temperature in the cycle is 2200 K and the compression ratio is 8.

Determine

A) the heat addition in KJ

B) the Net-work in kJ

c) the thermal efficiency

An ideal Otto cycle has a compression ratio of 10.5, takes in air at 90 kPa and , and is repeated 2500 times per minute. Using constant specific heats at room temperature, determine the thermal efficiency of this cycle and the rate of heat input if the cycle is to produce 90 kW of power.