The Sunyaev–Zel’dovich (hereinafter SZ) effect is a promising tool to derive the gas temperature of galaxy clusters. Approximation of a spherically symmetric gas distribution is usually used to determine the temperature structure of galaxy clusters, but this approximation cannot properly describe merging galaxy clusters. The methods used so far, which do not assume the spherically symmetric distribution, permit us to derive 2D temperature maps of merging galaxy clusters. In this paper, we propose a method to derive the standard temperature deviation and temperature variance along the line of sight, which permits us to analyse the 3D temperature structure of galaxy clusters by means of the thermal SZ effect. We also propose a method to reveal merger shock waves in galaxy clusters by analysing the presence of temperature inhomogeneities along the line of sight.