Expressions

Question 1

Isobaric?

Answer 1

p = constant

Question 2

Isentropic?

Answer 2

s = constant

• adiabatic & reversible

Question 3

s?

Answer 3

entropy = measure of the irreversibilty of a process

• belongs to 2nd law of thermodynamics
• when ideal process = s =constants
• either increases or remains constants
• reversible means no entropy change

Question 4

adiabatic?

Answer 4

no heat energy transfer
T2/T1 = T3/T4 = p2/p1 ^(k-1)/k

Question 5

isothermal?

Answer 5

T = constant

Question 6

Carnot cycle

Answer 6

• ideal reversible closed thermodynamic cycle
• most efficient
• Carnot efficiency: nc = 1- (T0/T)

Question 7

Enthalpy?

Answer 7

h [kJ/kg]

• measure of total heat present in system
• p=constant
• capacity to do non-mechanical work & to release heat
• used to calculate power output of a turbine

Question 8

Clausius Rankine cycle

Answer 8

• fuel used to produce heat within boiler
• converting water into steam which then expands through a turbine producing useful work
• steam power process

Question 9

Joule cycle

Answer 9

Gas turbines

Question 10

Exergetic efficiency

Answer 10

Carnot efficiency

NICHT in % angeben, sondern 0,31

Question 11

Watt in Megawatt

Answer 11

durch 1.000.000

Question 12

Paralellschaltung

Answer 12

1/R12 = 1/R1 + 1/R2

Question 13

Reihenschaltung

Answer 13

R345 = R3 + R4 + R5

Question 14

URI

Answer 14

U = Volt
I = Ampere
R= Ohm

Question 15

Power

Answer 15

Power [Watt] = I [A] * V [V]

Question 16

How to calculate the charge Q ?

Answer 16

I [A] = charge Q /time

Question 17

Where can electricity be stored?

Answer 17

Pumped storage
h2 storage
batteries

Question 18

What kind of current do PV & fuel cells produces?

Answer 18

DC - all formulas are DC

Question 19

Power formula for hydropower plants

Answer 19

1000 * 9,81 * height difference * volume flow * efficiency (wird nicht immer genutzt) = Power [W]

Question 20

COP

Answer 20

Coefficient of performance
> 1 for heat pumps
Formeln auswendig lernen!!!

Question 21

Watt in Megawatt

Answer 21

durch 1.000.000

Question 22

What is the difference between energy and power?

Answer 22

Energy = Joule
Power = Watt

Question 23

Energetic efficiency E when converting energy

Answer 23

100% * 60% * 95% * …= 45%

Question 24

Determine the exergy share

Answer 24

E * nc = 100% * 60% * 95% * …nc = mcp*delta T * nc

nc = you know

Question 25

What is the degree of utilization? or the efficiency?

Answer 25

useful work W [W] / supplied energy Q[W]

Question 26

What is daily energy demand?

Answer 26

(Capacity * Load hours)/ avg. efficiency

Question 27

How to interpol linearly?

Answer 27

y = y1 + ((y2 - y1)/(x2 - x1)) * (x - x1)

Question 28

What is Joule?

Answer 28

m^2kg / s^2

Question 29

MJ in MWh

Answer 29

1 MJ = 3600 MWh

Question 30

KJ in J

Answer 30

1 KJ = 1000 Joule

Question 31

How do you apply the 1st law of thermodynamics in a steam power process as a formula?

Answer 31

Q in - Q out + P in - P out = 0

Question 32

pv - diagram shows ….

Answer 32

useful work : alles W out; unten W in

Question 33

TS- diagram shows…

Answer 33

supplied energy: alles q in; unten q out