Thermodynamics Hipolito Sta Maria Solution Manual Chapter 5 Today
A counter‑flow heat exchanger transfers 1 MW of heat from hot oil (inlet: 450 °C, outlet: 150 °C) to water (inlet: 30 °C, outlet: 120 °C). The mass flow rates are 2 kg s⁻¹ for oil (cp = 2.0 kJ kg⁻¹ K⁻¹) and 5 kg s⁻¹ for water (cp = 4.18 kJ kg⁻¹ K⁻¹). Assuming steady‑state operation and negligible kinetic/potential energy changes, calculate the for the exchanger.
Each mini‑problem above is deliberately short—just enough to illustrate the method without overwhelming you. The solution manual you’re referencing typically expands each of these into full, step‑by‑step calculations. Below, we’ll walk through a representative example in more depth. Problem Statement (adapted from the manual) thermodynamics hipolito sta maria solution manual chapter 5
| Section | Key Objectives | Typical Example (Mini‑Problem) | |---------|----------------|--------------------------------| | | State the Clausius and Kelvin–Planck statements; introduce entropy as a state function. | Mini‑Problem: Show that a reversible isothermal expansion of an ideal gas between 1 bar and 5 bar yields ΔS = nR ln 5. | | 5.2 Entropy Changes for Simple Systems | Compute entropy changes for ideal gases, incompressible liquids, and pure substances using property tables. | Mini‑Problem: Using steam tables, find ΔS for water heating from 30 °C (subcooled) to 150 °C (still subcooled) at 1 bar. | | 5.3 Entropy Generation and Irreversibility | Identify sources of irreversibility (friction, mixing, heat transfer across finite ΔT). | Mini‑Problem: A heat exchanger transfers 500 kW from a hot stream (Tₕ = 400 K) to a cold stream (T_c = 300 K). Estimate the minimum possible entropy generation. | | 5.4 The Carnot Cycle and Thermal Efficiency | Derive η_Carnot = 1 – T_c/T_h and understand its significance as an upper bound. | Mini‑Problem: Compute the maximum efficiency of a heat engine operating between 800 K and 300 K. | | 5.5 Real Power Cycles (Rankine & Brayton) | Apply first‑ and second‑law analyses to generate expressions for η and net work. | Mini‑Problem: For an ideal Rankine cycle with boiler pressure 15 MPa and condenser pressure 10 kPa, estimate η using steam‑table data. | | 5.6 Refrigeration & Heat‑Pump Cycles | Derive COP_R = Q_L/W and COP_HP = Q_H/W, relate to Carnot limits. | Mini‑Problem: Find the COP of a vapor‑compression refrigerator that absorbs 120 kW at 273 K while rejecting heat at 313 K. | | 5.7 Exergy (Availability) Analysis | Define exergy, perform exergy balances, and calculate destruction. | Mini‑Problem: Compute the exergy destruction for the heat exchanger in the earlier example assuming ambient temperature 298 K. | | 5.8 Using Property Diagrams | Read and interpret T‑s, h‑s, and P‑v charts; locate state points for cycle analysis. | Mini‑Problem: Plot the ideal Brayton cycle on an h‑s diagram and label all processes. | A counter‑flow heat exchanger transfers 1 MW of