A Benign, Small-scale Power Unit for the Arctic: The Carnot Cycle Concept

• Main Author: G. S. H. Lock
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 1989
• Subjects: Key words; alternative energy; Carnot; OTEC; heat engine; power; Arctic
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.116.6020; http://pubs.aina.ucalgary.ca/arctic/arctic42-3-253.pdf

ABSTRACT. Small amounts of useful power may be generated in polar or subpolar regions during the winter period by placing a heat engine between a large body of water (near PC), acting as a heat source, and the atmosphere (near-25OC), acting as a heat sink. The scheme consists of a fuelless modular system operating on the Carnot cycle. Power is extracted by a reciprocating vapour engine drawing saturated vapour from a water-heated evaporator and exhausting to an air-cooled condenser from which nearly saturated liquid is returned to the evaporator using a reciprocating feed pump. The thermal performance model incorporates both the engine cycle power and the parasitic losses, the latter being incurred as a result of circulating the working fluid (ammonia), pumping water through the evaporator and blowing air through the condenser. Curves indicate power levels in excess of 1 kW, with thermal efficiencies around 5%. The power curves show a maximum with respect to speed. The principal difficulties with this scheme are in heat exchanger design in near-freezing water. The principal advantages are small power levels, flexibility through modular construction and reduction of the capital and operating costs associated with the supply of energy to northern regions.