Integration of the CHEST-System for Power-to-Heat to-Power

Integration of the CHEST-System for Power-to-Heat to-Power storage in Smart District Heating

DLR.de • Slide 1 >IRES 2017 >Henning Jockenhöfer/ Dan Bauer >16.03.2017

IRES 2017 Henning Jockenhöfer Dan Bauer

Electrical energy generated from wind and PV not dispatchable High share of renewable energy sources require storages Potential for pumped-hydro energy storages geologically limited Power-to-Heat-to-Power storage systems are a promising alternative

Motivation

DLR.de • Slide 2

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>IRES 2017 >Henning Jockenhöfer/ Dan Bauer >16.03.2017

Ideal efficiency: Carnot-factor of heat engine Real efficiency: ~35-40 %

Power-to-Heat-to-Power (PHP) based on resistance heating

DLR.de • Slide 3

G

Pel,discharge

Pel,charge

thermal energy storage (TES)


wind/pv

Ideal cycle: roundtrip efficiency = 100 %

PHP based on Pumped Thermal Energy Storage (PTES)

DLR.de • Slide 4

heat pump heat engine

thermal energy storage (TES)

heat source heat sink

charge discharge

Pel,charge Pel,discharge

T

s

T

s


wind/pv

Compressed Heat Energy STorage (CHEST) PTES based on subcritical Rankine-cycle

DLR.de • Slide 5

M

cold reservoir

hot storage

T

s

G

cold reservoir

hot storage

charge

discharge


Pel,charge

Pel,discharge

Temperature differences during heat transfer Isentropic efficiency of compressor and turbine

Exergy losses in real CHEST systems

DLR.de • Slide 6

T

s

storage temperature charged energy discharged energy exergy losses


design of thermal energy storage is crucial

Compensation of exergy losses by separation of heat source and sink

DLR.de • Slide 7

Suitable heat source?


T

s

Tsource

Tsink

charged energy

discharged energy

Smart District Heating (SDH)

DLR.de • Slide 8

renewable heat sources district heating

solar thermal biomass

seasonal pit water storage ~ 70000 m³


Smart District Heating (SDH)

DLR.de • Slide 9

renewable heat sources district heating

solar thermal biomass

seasonal pit water storage ~ 70000 m³


Source: Marstal District Heating

solar field

pit water storage

Sector coupling of the CHEST concept with SDH

DLR.de • Slide 10

M

district heating solar field

environment/seawater

thermal energy storage

charge discharge

G

Seasonal pit water storage ~ 70000 m³


consumer wind power

Organic Rankine-cycle (ORC) based CHEST

DLR.de • Slide 11

Detailed numerical investigation of the CHEST system Consideration of parasitics, pressure losses and isentropic machinery efficiencies


Parameter study of ORC-CHEST


power ratio =

Pel,discharge

Pel,charge Mode 1: Maximum power ratio No reuse of condenser heat

Mode 2: Medium power ratio Reuse of

condenser heat

Mode 3: Medium power ratio No reuse of condenser heat

Sector coupling of the CHEST concept with SDH Mode 1: power ratio = 1.25, Tsource=100 °C, Tsink= 15°C

DLR.de • Slide 13

M

solar field

thermal energy storage

charge discharge

G

1 MWel.

8.1 MWth.

1.25 MWel.

7.7 MWth.

90°C

40°C

100 °C

15 °C



wind power consumer

district heating

95 °C


DLR.de • Slide 14

M thermal energy storage

charge discharge

G

1 MWel.

6.7 MWth.

0.8 MWel.

6.8 MWth.

90°C

40°C

100 °C

50 °C


wind power consumer

solar field district heating

95 °C


DLR.de • Slide 15


charge discharge

M

1 MWel.

6.2 MWth.

1 MWel.

6.1 MWth.

90 °C

15 °C

85 °C



90°C

40°C

wind power consumer


Sector coupling of the CHEST concept with SDH Heat pump mode: power ratio = 0, Tsource=30 °C, Tsink= 80°C

DLR.de • Slide 16


charge discharge

M


80°C

30°C

wind power consumer


Conclusions Detailed Simulation of a CHEST-system was conducted. Flexible system operation in combination with Smart District Heating is possible. High electrical power ratio is attainable. Condenser and evaporator outlet heat is reusable in district heating. Development of suitable key components (compressor, latent heat storage) is

necessary. Outlook System simulations with detailed modeling of SDH Investigation of stand-alone water-steam CHEST for multi-MW scale without low

temperature heat integration

Conclusion and outlook


Thank you for your attention!

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Integration of the CHEST-System for Power-to-Heat to-Power