A renewable energy system for a grid remote village in India Gavin Walker Chair in Sustainable Energy Energy and Sustainability Research Division Faculty of Engineering

Partners University of Nottingham – Don Giddings, David Grant, Joel Hamilton Heriott-Watt (Tapas Mallick) Leeds University (Mohamed Pourkashanian) IITB (Prakash Ghosh) IITM (K Reddy) Visva Bharati University, West Bengal (Shibani Chaudhury) The Uttar Sehalai villagers

Figure 1: Maps showing the location of the village

Duration (h) Load (kW) Daily load (kW.h.day -1 ) Daily load (MJ) Health Water pumping Water purification Health care centre Health total Education Schooling Learn & earn Education total Enterprise Do & earn Enterprise total932.4 Lifestyle Lighting & cooling Lantern Entertainment LPG compressor Lifestyle total Auxiliary Auxiliary load Auxiliary total Total Estimated load profile for the village

Schematic of the BioCPV power plant METAL HYDRIDE STORE VILLAGE Crop, food, animal & human waste Anaerobic digester Generator Electrolyser Battery methane Energy storage hydrogen 150 Daily energy kW.h.day -1 CPV

Energy generation Concentrated photovoltaic (CPV) Concentrate light with a reflective material on to a PV cell. Reduces cost per watt as reflective material is cheaper than PV. Cogeneration of electricity and heat Solar radiation 540 [21.4] Electricity Solar tracking device Electricity 189 [7.5] CPV Usable heat [6.7] 60°C Daily energy: MJ.day -1 [Instantaneous energy: kW]

Energy generation - Anaerobic digester Utilises biodegradable waste Generates and regulates its own temperature – Therefore it is not part of the waste heat investigation Food waste Animal waste Crop waste Anaerobic digester Methane 270 [18.75] Carbon dioxide Fertiliser Daily energy: MJ.day -1 [Instantaneous energy: kW]

Power generation – ICE Generator Methane enriched with hydrogen 25% electrical efficiency Exhaust heat 29.6 [2.1] 350°C Methane 270 [18.75] Hydrogen 15.3 [0.7] Internal combustion engine Generator Electricity 70.2 [4.9] Cooling circuit heat [10.9] 80°C Daily energy: MJ.day -1 [Instantaneous energy: kW]

Energy storage - Battery Lead-acid battery (larger version of a car battery) Short term energy storage as these batteries self discharge No thermal management required Electricity 14.8 [1.1] Electricity 58.7 [2.3] Daily energy: MJ.day -1 [Instantaneous energy: kW]

Energy storage – Hydrogen Metal hydride store Heat Hydrogen 15.3 [0.7] 108 g.day -1 Electricity 21.6 [1.0] Deionised water 956 g.day bar Water vapour 0.04 g.day -1 Hydrogen 15.3 [0.7] 108 g.day -1 Oxygen 857 g.day -1 Hydrogen 15.3 [0.7] 108 g.day -1 Molecular Sieve Heat for regeneration Water vapour 0.04 g.day -1 Daily energy: MJ.day -1 [Instantaneous energy: kW]

Total daily load = 64.5kW.h.day -1 Projected generator and load profile

Waste heat analysis Generator exergy flow Heat engine η Carnot = 53% Cold reservoir (environment) 25°C Hot reservoir 80°C Hot reservoir 350°C Cold reservoir (environment) 25°C CH [17.5] (95.3%) H [0.9] (4.7%) Total [18.4] (100%) Coolant 26.7 [1.9] (10.1%) Exhaust 15.7 [1.1] (5.9%) Electricity 70.2 [4.9] (26.6%) Heat engine η Carnot = 17% Loss [10.4] (57.0%) Daily exergy: MJ.day -1 [Instantaneous exergy: kW] (% of exergy input)

z Daily energy (MJ) Instantaneous energy (kW) % of input energy Daily exergy (MJ) Instantaneous exergy (kW) % of input exergy Methane + Hydrogen % % Electricity % % Exhaust % % Cooling % % Other (aux, pumping, friction) %Included in losses Loss % Waste heat analysis Energy exergy overview

Waste heat analysis - Efficiency CPV Total daily load = MJ.day -1 Generator efficiency analysis Daily energy (MJ) Instantaneous energy (kW) Energy efficiency (%) Daily exergy (MJ) Instantaneous exergy (kW) Rational efficiency (%) Electrical % % Cogeneration exhaust only) % % Cogeneration (exhaust and cooling) % % Generator

There is a large quantity of waste heat energy Most of the waste heat has a low exergy as it is at low temperatures Waste heat better used for refrigeration as opposed trying to extract work This will improve the overall efficiency of the BioCPV energy system. Waste heat opportunity

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