Ferroelectric materials are widely used in small micro- and nanoelectronic devices and systems, allowing for the pyroelectric and electrocaloric effects inherent to them. After the development of nanotechnology and the finding of finite-size effects, thin layers and nanocomposites, including ferroelectric, were developed and became widespread. Similarly, the theoretical studies and description of the ferroelectric nanocomposites are highly relevant. However, Theoretical studies in this direction have a number of difficulties, for example, in early works the influence of the depolarization field was not taken into account, and other works focused on calculations for nanocomposites with a constant radius of nanoparticles within the entire nanocomposite volume. Earlier, we analyzed the influence of the parameters of the truncated normal distribution function of the nanoparticle radius on the electrocaloric and pyroelectric characteristics of ferroelectric nanocomposites. However, the temperature dependences of the ferroelectric material parameters were not considered in this work. Since the pyroelectric and electrocaloric effects, which are inherent to ferroelectrics, are interrelated through the pyroelectric coefficient, elucidating the behavior of the temperature dependence of spontaneous polarization and its derivatives with changes in the parameters of polar-active composite materials is a priority for both experimental and theoretical studies.Using the Landau-Ginzburg-Devonshire theoretical approach for noninteracting ferroelectric single-domain spherical nanoparticles of different sizes placed in a dielectric matrix, the temperature dependences of spontaneous polarization, electrocaloric temperature change, pyroelectric and electrocaloric properties were calculated. Changes in the form of these dependences at different values of the parameters of the truncated normal distribution of nanoparticles by size - the most probable radius and dispersion - are analyzed.It is shown that the spontaneous polarization, parameters of maxima of pyroelectric and electrocaloric coefficients, and electrocaloric temperature change at the same value of their dispersion strongly depend on the most probable radius, and at the same value of the most probable radius weakly depend on the dispersion. The obtained results open a new possibility of controlling pyroelectric and electrocaloric parameters of ferroelectric nanocomposites through the nanoparticle size distribution parameters, which can be important for applications in energy converters and microcoolers.