On both P-v and T-s diagrams, the area enclosed by the process curve represents the net work of the cycle.

Between a heat source at temperature T and a low-temperature heat well at 280 K power cycle is working. In steady state, the cycle produces 50 kW of work, while the heat well is 1000 kl/min. heats up. Determine the minimum theoretical value for T in K (Kelvin).

The manufacturer of the device claims that it accepts a heat transfer at a rate of QH = 3.0 kW from a low-grade source of geothermal heat at TH = 80ºC and rejects heat at rate QC to the atmosphere at TC = 20ºC. The device operates at steady state and produced work at a rate of W= 2.5 kW. There are no other heat or work transfers from the device. a.) What is the rate at which the device rejects heat to the atmosphere, QC ? b.) Is this device possible? Justify your answer using an entropy balance.

A system consisting of a gas contained in a cylinder with a frictionless piston is taken around the closed path a→b→c→a where the process c→a is isothermal. During the closed cycle, the system expels 150 J to the environment. If the work done on the system during the isobaric leg b→c of the cycle is 250 J, what is the heat expelled/absorbed by the gas in the isothermal leg c→a in J.