Geothermics

The change in enthalpy, dH, describes the....

a. total work delivered tot he system
b. total work done on the system
c. heat delivered to and non-mechanical work done on the system
d. non-mechanical work done on the system

Entopy is.....

a. intensive
b. sensitive
c. exhaustive
d. extensive

The magnitude of intensive quantities....

a. depends on the amount of substance
b. does not depend on the amount of substance
c. is extensive
d. is sensitive

Most phase transitions in the earth´s upper and lower mantle occur due to phase transitions of
high pressure forms of....

a. pyroxene
b. nickel
c. olivine
d. iron

The thermodynamic Grünseisenparameter combines?

a. elastic and thermal properties
b. electric and elastic properties
c. electric and thermal properties
d. magnetic and elastic properties

Heat capacity is the.......

a. temperature derivative of enthalpy
b. the pressure derivative of entropy
c. the volume derivative of internal energy
d. the entropy derivative of internal energy

The adiabatic exponent relates specific heat capacity to......

a. compressibilities
b. incompressibilities
c. bulk moduli
d.Grüneisen parameter

The Urey ratio (radiogenic heat generation rate/global heat flow rate), equals about....

a. 0.1
b. 0.4
c. 1
d. 4

The cooliung time of the earth, T = (commulative energy output)/diffusive heat flow rate), amounts to....

a. ~ one billion years
b. ~ four billion years
c. ~ ten billion years
d.~ one hundred billion years

The solar energy incident on the earth during one day is equivalent to how many years of global
primary energy production?

a. 1 year
b. 10 years
c. 30 years
d. 100 years

Assuming opacity, index of refraction, and spectral radiance to be independent of wavelength and temperature, "radiative" thermal conductivity turns out to scale with....

a. T^-3
b. T^-1
c. T^3
d. T^4

Rock thermal conductivity varies with temperature approximately......

a. linearly
b. inversely
c. quadratically
d. with the fourth power

Heat Radiation.....

a. becomes relevant for heat transport in rocks above temperatures of approximately 1000°C
– 1500 °C
b. can be aproximated by Fourier law comprising a "radiative thermal conductivity"
c. is irrelevant for optically intransparent rocks
d. is irrelevant for most of the Earth´s crust

Multi-component rock thermal conductivity is bounded from above an below by the.....

a. geometric and square root means, respectively
b. the Hashin-Shtrikman and effective medium means, respectively
c. the arithmetic and harmonic means, respectively
d. the Voigt-Reuss-Hill and geometric means, respectively

The advective specific heat flow is given by....

a. (pc)f "nabla" T*v
b. (pc)f "nabla" T*"nabla" v
c. (pc)f T*"nabla"v
d. (pc)f T*v

Thermal diffusivity of many rocks varies linearly with thermal conductivity within about......

a. +/- 2 %
b. +/- 5 %
c. +/- 10 %
d. +/- 20 %

Hydraulic permeability.......

a. depends on fluid and rock properties
b. depends only on fluid properties
c. depends only on rock properties
d. varies linearly with porosity
e. varies non-linearly with porosity

In the heat transport equation......

a. the diffusion term varies linearly with temperature
b. the advection term varies linearly with temperature
c. he diffusion term varies linearly with the temperature gradient
d. the advection term varies linearly with the temperature gradient

19. Darcy velocity (i.e. specific discharge) equals transport velocity.......

a. times kinematic viscosity
b. times porosity
c. over kinematic viscosity
d. over porosity

On average, the variation with porosity of the ratio of dry and saturated thermal conductivity is
best described by the.......

a. harmonic mean
b. Hashin-Strikman mean
c. geometric mean
d. square root mean

Hydraulically driven thermal anomalies under uneven topography are......

a. often characterized by 2D-Peclet numbers between 1 and 10
b. often characterized by 2D-Peclet numbers 0.1 and 1
c. purely conductivity
d. purely advective

The Péclet number......

a. equals the Nusselt number -1
b. the ratio with advection and conduction
c. is the ratio of heat condution and advection
d. is a measure for turbulence

Dynamic viscosity of water......

a. decreases by about 50 % between 300 K and 350 K
b. increases by about 50 % between 300 K and 350 K
c. decreases by about 5 % between 300 K and 350 K
d. increases by about 5 % between 300 K and 350 K

Which of the following are steady-state methods for measuring thermal conductivity?

a. Optical scanning
b. divided bar
c. Needle probe
d. Half-space line source

Which of the following are comparative methods for measuring thermal conductivity?

a. Optical scanning
b. divided bar
c. Needle probe
d. Half-space line source

Fiber optic borehole thermometers are accurate and precise to within.......

a. ± 1K and ±0.1 K, respectively
b. ± 0.1 K and ±0.01 K
c. ± 0.01 K and ±0.001 K
d. ± 0.001 K and ±0.0001 K

Fiber optic temperature sensing is based on.....

a. elastic scattering of protons
b. inelastic scattering of photons
c. the temperature dependence of the Stokes signal of Raman scattering
d. the temperature dependence of the Anti-Stokes signal of Raman scattering

Calibrated electrical resistance borehole thermometers are accurate and precise to within.....

a. ± 1K and ±0.1 K, respectively
b. ± 0.1K and ±0.01 K, respectively
c. ± 0.01K and ±0.001 K, respectively
d. ± 0.001K and ±0.0001 K, respectively

In a borehole filled with water, a twice steel reinforced seven-conductor cable is stretched under
it´s own weight per kilometer of cable by about

a. 7 mm
b. 7 cm
c. 7 dm
d. 7 m

Which method allows estimating the temperature disturbance in boreholes as a function of post
circulation shut-in time?

a. Birch approximation
b. Jefferys half-space
c. Horner-Plot
d. Bullard´s infinite cylindrical source

An annual harmonic surface temperature variation has a skin depth of approximately?

a. 1 m
b. 3 m
c. 10 m
d. 30 m

A constant surface temperature increase of 10 mK per Year can be seen in a temperature profile
recorded after one hundred years down to approximately

a. 20 m – 30 m
b. 50 m – 60 m
c. 100 m – 120 m
d. 150 m – 170 m

At distances of one time the horizontal length of a topographic ramp, left and right of this ramp,
the maximum topographic perturbation to specific heat flow is less than....

a. +/- 2 %
b. +/- 5%
c. +/- 12%
d. +/- 20 %

How many times the perturbation time is required approximately for a borehole to equilibrate to
about 10 Percent of the maximum perturbation?

a. 1-3 times
b. 6-8 times
c. 12-15 times
d. 24-27 times

Free convection in boreholes....

a. does not occur
b. causes Temperature variations on the order of tens of mK
c. varies linearly with borehole radius r
d. can be identified by temperature logging
e. varies with r-^-4

Which method enables the correction of drilling and mud circulation on bottom-hole
temperatures?

a. Bullard´s infinite cylindrical source
b. Jefferys half-space
c. Horner plot
d. Birch approximation

Climate is expressed, as a rule, by surface variables such as...

a. temperature alone
b. temperature and wind
c. precipitation, temperature, and wind
d. solar irradiation, precipitation, and wind

The Bullard plot is used to determine the....

a. skin depth of a climatic signal
b. average specific heat flow
c. the temperature perturbation time after borehole shut in
d. the appropriate mixing law for thermal conductivity of a multi-phase solid

Digital low-pass filtering of a temperature profile is obtained by.....

a. back transforming the product of the Fourier-transformed low-pass and temperature
profile into the space domain
b. deconvolving the product of low-pass and temperature profile
c. multiplying the Fourier-transforms of low-pass and temperature profile
d. dividing the Fourier-transforms of low-pass and temperature profile

Which (unless stated differently: steady-state) effects may introduce curvature in crustal temperature profiles?

a. variation of thermal conductivity with depth
b. variation of density with depth
c. vertical heat advection
d. downward diffusion of transient surface temperature variations

Harmonic variations of the Earth´s surface temperature of daily and annual periods penetrate to....

a depth of approximately several
a. millimeters and decimeters, respectively
b. centimeters and meters, respectively
c. decimeters and dekameters, respectively
d. meters and kilometers, respectively

The Maximum cooling due to the last glaciation (~ 10000 yrs ago) has diffused to a depth of about?

a. 120 m
b. 620 m
c. 1200 m
d. 2400 m
e. 4800 m

Non-unique problems can be solved by?

a. oversizing
b. standardizing
c. regularizing
d. non- dimensionalizing

Problems lacking a solution may be still solved?

a. in a least squares sense
b. in a worst case scenario
c. in a best case scenario
d. by the method of steepest descent
e. by the method of moving asymptotes

Inversion of past ground temperature variations from borehole temperatures is a problem which
is
a. well-posed
b. ill-posed
c. under-determined
d. over-determined
e. both under. And over-determined

Resources comprise...

a. undiscovered and identified resources
b. economic and sub-economic resources
c. other occurrences
d. unconventional and low-grade occurrences

Reserves are?

a. sub-economic resources
b. identified and undiscovered resources
c. identified resources
d. undiscovered resources

Global geothermal reserves amount to approximately.....

a. 5 EJ
b. 50 EJ
c. 500 EJ
d. 5 000 EJ
e. 50 000 EJ

By the end of 2014, the global annual production of direct use geothermal heat amounted to about?

a. 590 TJ
b. 590 PJ
c. 590 EJ
d. 590 ZJ

By which factor does the global heat flow exceed the annual German consumption of primary energy?

a. 100
b. 1 000
c. 10 000
d. 100 000

The coefficient of performance (COP) of ground-source heat pumps is the ratio of...

a. heat input and electrical energy output
b. thermal output power and heat pump input power (@ optimal operating conditions)
c. thermal output power and heat pump input power (@ maximum thermodynamic
efficiency)
d. heat output and heat output

The efficiency ᶯ of ground-source heat pumps is the ratio of....

a. heat output and heat input
b. thermal output power and heat pump input power (@ maximum thermodynamic
efficiency)
c. thermal output power and heat pump input power (@ optimal operating conditions)
d. heat input and electrical output energy

The heating efficiency ᶯ of a ground-source heat pump (exergy factor: 0.5) for a temperature lift
of ΔT=30 k is?

a. 3
b. 4
c. 5
d. 6

The Fourier number Fo is the ratio of....

a. heat conduction and heat storage
b. heat storage and heat production
c. heat conduction and heat production
d. heat production and heat diffusion

The specific power of heat exchanger piles is?

a. 2 W/m – 7.5 W/m
b. 20 W/m – 75 W/m
c. 2 kW/m – 7.5 kW/m
d. 20 kW/m – 75 kW/m

The specific power of deep borehole heat exchange is approximately?

a. 10 W/m to20 W/m
b. 20 W/m to55 W/m
c. 65 W/m to 95 W/m
d. 20 kW/m to 55 kW/m

Deep borehole heat exchangers may be economical compared to gas turbines (for assumed lifetime of technical components) for annual operation times of at least?

a. 2000 h
b. 4000 h
c. 6000 h
d. 8000 h

With sustainable data and procedures, uncertainty in temperature explorations in reservoirs may be reduced by a factor of up to about?

a. 0,3
b. 3
c. 30
d. 300

How much kg of hot water (85°C to 150°C) do binary cycle plants require per kWhe?

a. 4
b. 40
c. 400
d. 4000

How much more steam do non-condensing cycle plants require than condensing cycle plants?

a. twice
b. three times
c. five times
d. ten times

How much kg of steam do condensing cycle plants require per kWhe?

a. 0.6-1.0
b. 6-10
c. 60-100
d. 600-1000

The global installed capacity of geothermal power by the year 2015 amounted to about?

a. 1,3 GW
b. 13 GW
c. 130 GW
d. 1,3 TW

Geothermal power has been produced since the year?

a. 1878
b. 1904
c. 1927
d. 1954

Hydraulic fractures nucleate if the stress regime is?

a. sub-critical
b. critical
c. super critical

In hydraulic fracturing, the number of induces seismic events depends on the....

a. level of natural seismic
b. injection period
c. maximum seismic magnitude in last decade
d. injection pressure
e. critical pressure
f. minimum reflection coefficient
g. number of natural cracks per rock volume

Successful Engineered Geothermal Systems (EGS) require minimum flow rates of?

a. 0.5 L/s – 1.0 L/s
b. 5 L/s – 10 L/s
c. 50 L/s – 100 L/s
d. 500 L/s – 1000 L/s

Commercially successful EGS require a minimum effective heat exchange surface of?

a. 50 m2 -100 m2
b. 500 m2 -1000 m2
c. 5 km2 -10 km2
d. 50 km2 -100 km2

What is he reason for the improved efficiency by 3 % to 10 % of Kalina vs. the ORC cycle?

a. higher operating temperature
b. lower evaporation temperature
c. higher operation pressure
d. variable evaporation temperature

What is the average efficiency ᶯ of ORC binary plants in the temperature range 85°C -170°C?

a. 6 % - 12 %
b. 15 % - 30 %
c. 35 % - 50 %
d. 55 % - 70 %

Specific turnkey power plant investment and duration for the development of a (wet or dry) steam field and the power plant installation are?

a. ~ 1 million Euro per MW & 3 years
b. ~ 5 million Euro per MW & 6 years
c. ~ 10 million Euro per MW & 15 years

Typical investment cost per kW installed capacity for ORC or Kalina systems varies between?

a. 500 € - 1000 €
b. 1000 € - 1600 €
c. 1600 € - 3200 €
d. 3200 € - 6400 €

Maximum emission of CO2 from continental geothermal power stations is about?

a. 4 (g/kWh)
b. 40 (g/kWh)
c. 400 (g/kWh)
d. 4 (kg/kWh)

Which physical law provides the basis for the expansion method for determining porosity?

a. Boyle-Mariotte (pV gleich constant)
b. Hagen-Poiseuille
c. Stefan-Boltzmann
d. Gay-Lussac

Typical specific power in W/m of shallow borehole heat exchange is?

a. 1-10
b. 80-95
c. 40-55
d. 60-75

Which mixing law is appropriate for calculating the effective specific capacity of a water rock system?

a. geometric mean
b. arithmetic mean
c. harmonic mean

Which parameter controls the steady-state conducive heat transport (without heat production)?

a. thermal diffusivity
b. thermal conductivity
c. specific heat capacity

Specific discharge (or Darcy velocity)..?

a. is homologous to specific heat flow
b. follows a Fourier law
c. is homologous to electric current

Which single parameter controls the transient conductive heat transport (without heat production)?

a. thermal diffusivity
b. specific heat capacity
c. thermal conductivity

Which elements contribute to radiogenic heat generation in rocks?

a. Uranium
b. Thorium
c. Potassium
d. Calcium