DefinePK

Abstract

Heat exchanger is a device that facilitates the exchange of heat with different temperature between two or more fluids with or without phase changes. Energy recovery by using ORC system is an effective method to recover low grade heat source because organic fluid employs low saturated temperatures in comparison to water. This paper presents the design of a cross flow Organic Rankine Cycle (ORC) condenser using numerical modeling. In this paper, the condenser is numerically design to obtain a designated model for a 3kW heat load with 1kW turbine power. This is achieved by obtaining a suitable mass flow rate using the ORC calculation with 70 % turbine efficiency. Apart from that, the design of the condenser also considers; (1) the size of an extruded finned tube, (2) types of working fluid and (3) fluid temperatures. The condenser design point was established for 75:25 of ammonia-water concentration mixture. Theoretical results show that the requirement number of tube, n is 36 tubes. At n=36, the characteristic of the condenser shows the heat transfer coefficient, UA, of the condenser is 88% higher compared to the base fluid. The internal heat convection occur at the condenser is 28% difference with the external heat convection. This is because of the enhancement by factor of thermal conductivity; k of the mixture is higher compare to the base fluid.