PRESENTATION OF THE EDF GROUP 1

Working fluid selection and performance comparison of Organic (ORC) for low temperature waste recovery

within

CERES project

Stéphanie JUMEL EDF – R&D Department on Eco Efficiency of Industrial Processes Site des Renardières 77250 Moret sur Loing – France

Van Long LE – Michel FEIDT – Abdelhamid KHEIRI Theoretical and Applied Energy and Mechanics laboratory CNRS, LEMTA, UMR 7563 54500 Vandœuvre-lès-Nancy - France Context

High potential of in industrial processes (solid, liquid, gaz) Full range of waste heat recovery technologies Require global and complex approaches (i.e. energy integration methods)

ECEEE – 11-14 September 2012 2 CERES : project presentation (1/3)

CERES : Chemins Energétiques pour la REcupération de chaleur dans les Systèmes industriels « Energy pathways for optimized industrial waste heat recovery » 3-years project (2011-2013) Co-funded by the French National Research Agency 11 partners

Acdemic partners Industrial partners

ECEEE – 11-14 September 2012 3 CERES : project presentation (2/3)

Objective : Develop a decision-making tool based on § industrial process modeling § energy integration methodology § optimization tools

Deliverables : § Models of industrial process unit operation (e.g. dryer, furnace, …) § Models of heat recovery technologies (compression and sorption heat , ORC, HEX, thermoelectricity) § Methodology to identify waste heat recovery opportunities and design solutions § Simulation and optimization platform (called CERES) Models in Modelica language Industrial sectors addressed during the project § Food & drink (dairy process) § Pulp & paper § Steel making ECEEE – 11-14 September 2012 4 CERES : project presentation (3/3)

ECEEE – 11-14 September 2012 5 Organic Rankine Cycles model

ECEEE – 11-14 September 2012 Subcritical Organic Rankine Cycles

First built in 1883 W. Ofeldt (naphtha engine)

Same as steam Rankine cycle

T [K] R245fa shi sh3 4 400 3 2050 kPa sho

350 480 kPa 5 300 1,2 6 sco sci sc6 250

0.75 1.00 1.25 1.50 1.75 s [kJ/kg-K]

ECEEE – 11-14 September 2012 Supercritical ORC

/ exit of condenser directly pumped from statured liquid state to supercritical pressure Exchange with source at higher Temperature & avoid 2 region -> less irreversibility

Supercritical used when Tc > Tsource

R245fa 200 hsi hso 3 150

2,00E6 Pa 100

4 50 470000 Pa 1,2 5 T [°C] T csi cs5 cso 0 51000 Pa

-50 0,2 0,4 0,6 0,8 1000 Pa

-100 250 500 750 1000 1250 1500 1750 2000 2250 2500 s [J/kg-K] Disadvantages : operation at high pressure, investment costs

ECEEE – 11-14 September 2012 Selection of working fluids

Based on § hot source temperature § cooling fluid temperature (or ambient temperature)

Other criteria § high enough critical point § acceptable saturation pressure to avoid condensation at the turbine exit

T [C] Dry Fluid 3 groups of organic fluids 200 Isentropic Fluid

150 § dry fluids (ds/dT > 0) Wet Fluid 100 Hexane R141b

Ammonia § isentropic fluids (ds/dT = 0) 50 § wet fluids (ds/dT < 0) 0

-50 0 1000 2000 3000 4000 5000 6000 s [J/kg-K]

ECEEE – 11-14 September 2012 Selection of working fluids

Other criteria (cont’d) § high density, low to avoid losses in heat exchangers § high thermal conductivity to optimize exchanges in HEx § thermal and chemical stability in time § non toxicity, slight smell, easy leak detection for safety § low cost

§ Fluid selection methodology (Teddig et al. World Engineer Convention, 2011) § Literature review on existing fluids § first selection based on hot and cold sources temperature § second selection focused on environmental and safety criteria § third selection based on thermodynamical criteria § check availability of corresponding expansion machine

ECEEE – 11-14 September 2012 Thermodynamic modeling

§ Fluids tested in this study § Hydrofluorcarbons (HFCs) R245fa, R236fa, R152a, R227ea, R134a, R32, R143a, R125 § Hydrocarbons (HCs) R-290, R-600, R-600a, R-601 § Hydrochlorofluorocarbons (HCFCs) R141b, R123, R142b, R124, R22, E, R-717, R1234yf

Conditions

§ Evaporation @ 90°C for subcritical, P=1.03 Pcrit. for supercritical fluids § Ambient temperature (20°C) to cool down and condense working fluid § Hot air flow rate : 0.2 kg/s, Water flow rate 0.5 kg/s

ECEEE – 11-14 September 2012 Results (1/4)

Thermal efficiency

§ subcritical cycle supercritical cycle hth 2.6 0.12 e tot hth e tot

0.115 2.4

0.11 2.2

0.105 2

0.1 1.8 0.095

1.6 0.09

0.085 1.4

R22 R124 R123 R134a R142b R152a R141b R227ea R236fa ButaneR245fa R245ca R1234yfPropaneR1234ze Isobutane n-Pentane

§ HEx surface area

ECEEE – 11-14 September 2012 Results (2/4)

losses

§ subcritical cycle supercritical cycle

] I [W] 0.4 2100 h 0.5 3500 h W [ II

h 0.36 I 0.45 1800 hth 3000 0.32 0.4 I tot 1500 0.28 0.35 I HTHEX 2500

0.3 I LTHEX 0.24 1200 Itot I t 2000 0.25 0.2 h II IHTHEX I P ILTHEX h th 900 0.2 1500 0.16 It IP 0.15 0.12 600 1000 0.1 0.08 300 0.05 500

0.04 0 0 0

R22 r32 R22 R124 R123 r125 R124 R134a Butane R142b R152a R141b r143a R134a R152a R142b R227ea R236fa R245fa R245ca R227ea R236fa Butane R245fa R1234yfPropaneR1234ze ammonia R1234yf Propane R1234ze isobutane n-Pentane isobutane

ECEEE – 11-14 September 2012 Results (3/4)

Effect of Evaporating Temperature (sub-) and Saturation Pressure (super-)

§ subcritical cycle supercritical cycle

hth hth 0.15 0.17 R245fa R245faR245fa 0.145 Butane 0.16 R141bR141b R245ca 0.14 R142b R123R123 0.135 0.15 n-Pentane Butane 0.13 R142b 0.14 R124 0.125 R236fa 0.12 0.13 R152a 0.115 R124 R22 0.12 0.11 R236fa R1234ze 0.105 R1234yf 0.11 R152a 0.1 R134a Isobutane 0.1 0.095 Propane

0.09 x 6 x 6 x 6 x 6 x 6 90 100 110 120 130 140 150 3.500 10 5.000 10 6.500 10 8.000 10 9.500 10 Tevap [C] Ph [Pa]

ECEEE – 11-14 September 2012 Results (4/4)

Synthesis – R245fa

Supercritical cycle Subcritical cycle

R245fa Ph = 1.03 Pcrit Tevap = 140 °C Tevap = 150 °C T [°C] Subcritical (Tevap = 150 °C) tot 1.926 2.01 1.977 Supercritical (Ph = 1.03Pcrit) Subcritical (Tevap = 140 °C) 150 th 15.02 14.57 15.01

II 48.5 47.2 48.47 2,00E6 Pa 100 Exergy destruction 911.1 970.3 913.8 [W] 4 50 470000 Pa Heat in [W] 6657 6861 6662 1,2 5

Heat out [W] 5510 5717 5516 0 51000 Pa Work turbine 1106 1081 1094 [W] 0,2 0,4 1000 Pa 0,6 0,8 bwr 0.096 0.075 0.086 250 500 750 1000 1250 1500 1750 2000 2250 2500 s [J/kg-K]

P 21.15 15.91 19.09 [kg/s] 0.0260 0.0242 0.0247

• • W t +WP,water bwr = • Wt

ECEEE – 11-14 September 2012 Conclusion - Perspectives

Various working fluids have been studied with subcritical and supercritical configuration of organic Rankine cycle.

Subcritical ORC : Maximum thermal efficiency is achieved with Ammonia but a big superheating is required to avoid its vapour condensation during the expansion.

R141b, R123 and R142b are the most appropriate fluids with relative high thermal efficiency and low heat exchange surface area in this case. The alternative fluid, i.e. R245fa, present its potential with a relative high thermal efficiency and the desirable properties for the safety and the environment.

Supercritical R245fa gives the maximum thermal efficiency and surface area

ECEEE – 11-14 September 2012 Conclusion - Perspectives

Cycle performance of ORC is improved with supercritical configuration

But some disadvantage such as higher operating pressure, higher back work ratio and working flow rate are considered for this case.

The consequences and coupling of fluid properties on the design and cost of the system remain to be specified and seems to be very sensitive.

It is the present goal of the continuing study in the labs

ECEEE – 11-14 September 2012