220 likes | 511 Views
Mapping of performance of pumped thermal energy storage (Carnot battery) using waste heat recovery. Olivier Dumont a & Vincent lemort a a University of Liege (Belgium). Context. Problem with renewable energies = storage of electricity Smartgrid + benefits Problems with batteries
E N D
Mapping of performance of pumped thermal energy storage (Carnot battery) using waste heat recovery Olivier Dumonta & Vincent lemorta a University of Liege (Belgium)
Context • Problemwithrenewableenergies = storage of electricity • Smartgrid + benefits • Problemswith batteries • Cost (rare materials) • Lifetime (<20 years) • Recycling (impact CO2) • Solution = Thermal battery • Charge = heat pump (electricity heat) • Discharge = Power cycle (heat electricity) • Emergingtechnology (1st protos 2019-2020) • Cheap, no rare materials, lifetime Electricité Electricité Chaleur Chaleur
Waste heat Recovery TIPTES (hot) PTES TIPTES (cold) Twaste Tstorage Thot ORC HP ORC ORC HP Tair Twaste HP Tstorage Tair Tcold Efficiency < 70 % Efficiency ≈ 100 %
Reversible HP/ORC unit • One unit able to work as HP and as ORC • Cheap • Constraints (Reynolds,efficiency) Dumont, O., Quoilin, S., Lemort, V., 2015. Experimental investigation of a reversible heat pump/organic Rankine cycle unit designed to be coupled with a passive house to get a Net Zero Energy Building, Int. J. Refr. 54:190–203.
Modeling • Hot or cold TIPTES? • MCP or sensible storage? • Sizing? • Compressor/expander • Fluid • Compactness • Performance? • Architecteure(no exp valve, one exp, reverse) • Comparisonwith batteries
Influence of the glide • Low for roundtripefficiency • High for compactness of sensible storage
Influence of air and wastetemperature • Fluid • R1234y<<R1233zd(E) • RC and roundtripefficiencies • Increasewithwaste • Decreasewithair • COP • Rather constant (lift) • Hot>>Cold • Thermodynamics • Compatibility (Re) Lift=10
Influence of the volume ratio • Similar value in a given range • Generallybetterwithtwodifferentvolumetric machines hot cold
Compactness • PCM vs sensible Ratio_re=1 Ratio_re=3
Sensitivityanalysis Accurate design and control required
Conclusions • PTES + waste heat + reversible HP/ORC Cheap electricitystoragewith high effciency • Cold climates + high waste heat temperature for high roundtripefficiency • Hot > cold • Interest for mcp due to the necessarylow lift • High sensibility to the parameters accurate design and modelingnecessary • Need for a demonstrator, part loadmodel • Large scale better perf
FAQ • Low lift, low WHR • Carnot storage , first aimis no WHR • Transcritical cycle? • Not fairroundtripefficiencybecause WHR • Whatisreallyseen by the grid • Recover Heat from condenser • Practicallycomplicated • Lowcompactness • Mcp, higher glide, transcritical cycle, Re_ratio • Doesitwork?