Engineering Calculation and Experimental Study of a Cone-Shaped Coil Heat Exchanger

Abstract

To improve the characteristics of heat and power equipment, it is necessary to develop new designs of heat exchangers, increase the efficiency of heat exchange surfaces, apply modern approaches to the design and calculation of heat exchangers, and create new technologies for their production. The paper proposes modern compact coil heat exchangers of the in pipe type with a variable bending radius of the helical spiral and the engineering method calculating the thermohydrodynamic characteristics of such devices. The calculation of a coilheat exchanger with a linearly varying bending radius of a helical spiral (cone-shaped coil heat exchanger) has been performed. They performed the experimental study of heat transfer in a cone-shaped coil heat exchanger of the pipe-in-pipe type. They obtained the empirical formulas for the Nusselt number and hydraulic resistance coefficient. It has been established and experimentally confirmed that cone-shaped coil heat exchangers are morecompact and efficient in comparison with the known cylindrical coils. It is proposed to modernize the hot water preparation unit in one of the residential buildings in the city of Kazan (Russia) by replacing the outdated shelland-tube heat exchanger with a compact cone-shaped coil heat exchanger, which made it possible to reduce the duration of hot water preparation significantly, to reduce the costs of the heating medium and, thus, to reduceconsumer costs.