Today Electric Power Lecture Carbon Trading Game Assignment 2 posted Thursday Electric Power Distribution and Storage Lecture Homework 3 (Conservation) due at start of class Group homework using eQUEST One homework/group Discuss Homework 3 Present an example problem to help with Homework 4 At 6 pm, reading quiz for Electric Power due

Country Name Sustainable Energy Problem ## Problem Statement and schematic: In the college of engineering many hallway lights are on when sunlight is available to light the hallways. There are lighting systems which turn lights on when the ambient light level drops below a given value, and turn them off when ambient light levels exceed the given value. Estimate the amount of energy (in kW-hr) that could be saved next month if the mechanical engineering wing used one of these lighting systems. Figure 1: Map of the engineering center 1

Week 4 Electricity Generation, Transmission, and Storage

37 % 25 % 38 % 13 % 11 % Why Care?

International energy agency, 2003 Where is this electricity coming from? 39.9% 19.3% 16.3% 15.7% 6.9% 0.83% 0.37% % 0.40% Includes wind steam turbine gas and steam turbines steam turbine water turbine How is it created?

So, what are we going to talk about most of the day?

Steam Trivia: How much water do we (earthlings) change to steam every year in the name of electricity demands? A. 10 km 3 B. 55 km 3 C. 6,000,000 m 3 D. 190,000,000 m 3 Salt Lake holds 16 km 3 of water

s future2001 Britain producing 5x more coal than rest of the world. Running out of accessible supply. Coal mines had to stop at the water table. mine coal water table

s future st Newcomen engine (steam engine) was installed at a mine, to pump water out so they could dig deeper. And, humans crossed the threshold.

control volume 1 st Law of Thermodynamics: Energy in – Energy out = ∆Energy cv chemical potential energy of coal electrical energy zero (on average) & heat 33%67% How do we analyze?

work in boiler turbine pump fuel air work out heat out heat in no heat constant s no heat constant s no work constant P no work constant P T boiler External Combustion Engine Closed Cycle Reversible Heat Engine Most efficient type? condenser generator electricity Carnot Steam Engine T pond

What is the Carnot efficiency? For coal-fired power plants, maximum T boiler = 600 °C Ambient water (or air), T pond = 10 °CFor nuclear power plants, maximum T boiler = 300 °CWe keep reading that steam power plants are closer to 33 % efficient. Why the discrepancy? Reversible closed cycle involving a two-phase substance cannot realize the Carnot efficiency.

T s boiler turbine pump work in work out heat out heat in condenser What is this plot describing? superheated vapor saturated liquid & vapor compressed liquid Saturation Dome for Water/Steam critical point constant pressure lines Rankine Cycle w pump,in w turb,out q cond,out q boiler,in 3

T s boiler turbine pump work in work out heat out heat in condenser How do we improve efficiency? Increase area of shape ’ 1’ 2’ lower condenser pressure Problems: P min

T s boiler turbine pump work in work out heat out heat in condenser How do we improve efficiency? Increase area of shape 1234 superheat steam to higher T 4’ 3’ Problems: T max Q in limits

T s boiler turbine pump work in work out heat out heat in condenser How do we improve efficiency? Increase area of shape 1234 increase boiler pressure 4’ 2’ 3’ Can we fix this? Add Reheat

T s boiler turbine pump work in work out heat out heat in condenser How do we improve efficiency? Increase area of shape 1234 Preheat feedwater Regeneration 6

boiler turbine pump fuel air work in work out heat out heat in T boiler T pond generator condenser electricity

+airproducts+heatcoal heating value of coal = 24 – 35 MJ/kg CH 0.67 O N S (O 2 + N 2 ) CO 2 + H 2 O + NO + SO 2 + N 2

+airproducts+heatcoal CO H 2 O NO SO 2 + N 2 + Moles of O 2 per mole of C = ½ ( – 0.043) = CH 0.67 O N S (O N 2 ) Greenhouse gas No worries Toxic & ozone friend Toxic & PM friend Toxic More Toxic incomplete combustion (1-x) CO 2 + x CO H 2 O + (0.010+y) NO SO 2 + (4.261-y) N 2 + PM complete combustion + mercury

Total = 3500 deaths/year ( – 95% confidence) If we were to use the numbers from that study, along with western air pollution values … (310) (1560) (110) (450) (860) (100) (200) (50)

You tell me – how efficient can you make a heat exchanger? How do you get this efficiency? Heat

You tell me – how efficient can you make a turbine? How do you get this efficiency? InternalKinetic Design

Turbine picture

!91 MW from coal-fired steam Valmont Power Station Boiler operates at 21 MPa and 534 °C The condenser is at