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Department of Engineering, ICT and Technologies for Energy and Transport Patent Title Thermoionic solar converter. Ref. CNR 10268 Assignee(s): CNR CNR InƐƟƚute: INSEAN Main Inventor: Massimo Adriani Countries: IT, EP, US Priority date: 25/02/2011 Abstract The present ŝŶǀĞŶƟŽn refers to a device for the geneƌĂƟŽŶ of electricity from concenƚƌĂƟon solar source and the ĐŽŐĞŶĞƌĂƟŽn of hot water at low temperature. It can be used in systems for single user or ƉƌŽĚƵĐƟon plants in linear arrays. This device – essenƟally a vacuum tube – is designed to operate at the highest temperature tolerated by conĚƵĐƟve refractory materials and allows to exploit the full thermal gradient of a top thermodynamic cycle to the lowest available temperature to the cooling system. This allows to obtain parƟcularly high electrical conversion ĞĸĐŝĞŶĐy - esƟŵĂted in the order of 45% - and a recovery of cogeneraƟon in the order of 15%; furthermore, it allows obtaining an ĞƐƟŵĂted ĞĸĐŝĞŶĐy of 60%, occupying an area which represents a half of the current plant (for the same amount of produced electric power). Background The current thermionic converters exhibit very low eĸciency owing to heat losses due to the very high opeƌĂƟŶg temperatures. This device solves this problem by using measures to limit thermal losses, both internal and external. This allows to increase the ŽƉĞƌĂƟŶŐ temperatures and the t to the maximum levels tolerated by refractory materials and hence the ĞĸĐŝĞŶĐLJ͘ Technology The system is composed of linear modules comprising a mirror (plane parabolic) that concentrates the solar radiĂƟon on a cathode placed at the center of a vacuum tube suspended at the ends, with internal shields placed on the walls, and anodes cooled by internal piping. It’s assumed a conversion module of 1 kW of power with 1 m of length, opening mirrors of about 2.5 m, with a concenƚƌĂƟŽŶ ƌĂƟŽ in the order of 100-200. Advantages and ApplicaƟons Installing 6 Modules x1 kW it’s ƉŽƐƐŝďůĞ ƚŽ ĂĐŚŝĞǀĞ Ă ƉƌŽĚƵĐƟŽŶ ƉůĂŶƚ ĨŽƌ ŝŶĚŝǀŝĚƵĂů ŚŽŵĞ ƵƐĞƌƐ ǁŝƚŚ Ă footprint of 15 square meters instead of 42 square meters needed to the current commercial photovoltaic, and a ĐŽŐĞŶĞƌĂƟŽn thermal power of 1.5 kW to 80°; obviously, it’s possible to realize manufacturing plants by installing several rows of connected modules Development stage The invenƟon doesn’t have a ƉƌŽƚŽƟƉĞ yet. 31