MICRO-COGENERATION AND DESALINATION USING ROTARY STEAM ENGINE (RSE) TECHNOLOGY Kari Alanne, Kari Saari, Maunu Kuosa, Md. Mizanur Rahman* Andrew Martin** Heikki Pohjola*** *Aalto University, Espoo, Finland **Kungliga Tekniska Högskolan, Stockholm, Sweden ***Novoro INC, Espoo, Finland
Presentation outline Introduction and objective of the work RSE technology Applications: -micro-cogeneration -desalination State-of-the-art
Backgound: Introduction the market calls for new innovations for micro-polygeneration requirements: overall energy efficiency, applicability of local heat resources, small physical size, low costs Objective of the work: to reflect and review the applicability of rotary steam engine (RSE) within on-site micro-cogeneration and desalination
Rotary steam engine (RSE)-I Aalto University, Dept. of Energy Technology Developed by Novoro Inc. in collaboration with Aalto University since 2006 Operational principle: Rankine cycle Characteristics: Utilize 150...200 ºC vapor (5-15 bar) Oil free, noiseless, 1000-2000 RPM Compact size, power/weight ratio Connection to generator without gearing Versatile sources of heat (e.g. biofuels or solar energy) Estimated installed cost of a similar magnitude as for micro-chp plants based on internal combustion engines Generator 0.34 m flywheel 4 kw e /20 kg RSE
Rotary steam engine (RSE)-II Aalto University, Dept. of Energy Technology Consists of two chambers: V 1 is filled with constant pressure steam, expansion takes place in the chamber V 2 Final pressure p 2 after the RSE in chamber 2 not the condenser pressure, it depends on the expansion volume ratio V 2 /V 1 After the expansion, the outlet valve opens and the steam flows from RSE to condenser achieving the final condenser pressure p 3 in vacuum conditions The waste heat of RSE is delivered as steam: easy and effective to utilize
Integration of micro-cogeneration in buildings Electricity to grid Exhaust gases µchp plant >80ºC Fuel and air Electricity to HVAC, lighting and appliances Cold water Buffer storage 60 80ºC* Controller Circulating pump * Multiple thermal sources can be switched with the storage tank. The storage temperature is controlled by heat sink and auxiliary burner. Hydronic radiators network or floor heating 40 70/ 20 40ºC Domestic hot water 55ºC
Schematic diagram of RSE-µCHP plant Fuel & air to CHP Exhaust gas from CHP Heat loss to ambient Steam boiler Steam engine G Electricity to/from grid Power management unit Electricity to HVAC lighting appliances Condenser Cooling water out Cooling water in
Integrated RSE + boiler T supply T outdoor Boiler water: 90 95ºC TC TC G RSE 100 160ºC Condenser Supply water: 70ºC Hydronic radiators network or floor heating Evaporator Return water: 40ºC ON/OFF 300ºC Firebox (combustion space) Water
Energy flow modelling with 3 control volumes based on IEA/ECBCS Annex 42 model for combustion engines electrical and thermal efficiency will be determined experimentally as a 4 10- term, multi-variable polynomial function of P net,ss, T cw, in and T cw, out will be implemented in building simulation programs (e.g. IDA- ICE) and employed in wholebuilding dynamic simulations for techno-economic performance assessments Fuel in q gross Air in Thermal mass Cooling water Cooling water in T cw,i, Steam boiler control volume Engine control volume, T eng Condenser control volume Exhaust gas out Generated heat q gen,ss Recovered heat Energy conversion Electricity P net,ss Thermal loss q skinloss Cooling water out T cw o,
RSE in desalination Waste heat from RSE A shortage of water supply is becoming a serious concern worldwide Much attention is paid to the production of drinking water by sea water desalination The condenser of Rankine cycle can be used as primary heat source for the multi-stage flash (MSF) distillation plant
RSE in desalination Distillate production rates for 10 kw e RSE with MSF plant: 150 kg/h (at steam temperature of 60 ºC) 600 kg/h (110 ºC)
RSE in solar power desalination Solar panel as heat source Condenser delivers the waste heat to the feed water flow Part of the water flashes repeatedly in all distillation stages of the evaporator & condences on the preheater surfaces The plant can be constructed on top of a barometric siphon, when the needed vacuum is achieved and maintained
State-of-the-art-I Aalto University, Dept. of Energy Technology Ongoing pilot project for a 2-4 kw e / 20 kw th pellet-fuelled Novoro2, funded by Finnish Funding Agency for Technology and Innovation (Tekes) Novoro Inc. collaboration with Applied thermodynamics research group since 2006 1,8 kw e /1500 rpm water jacked cooled permanent magnet generator Test run of NOVO2 RSE
State-of-the-art II Aalto University, Dept. of Energy Technology Funding has been applied for commercialization of micro-chp plant plant layout design and optimization construction of prototype plant experimental analysis laboratory testing field testing Droplet separator Generator Steam boiler Pellet burner Feed water tank RSE Condenser Radiator The RSE plant should not require significantly more room as do the traditional heating systems (e.g. domestic heating boiler).