The Proton Improvement Plan II (PIP-II) project at Fermilab aims to upgrade the particle accelerator complex to generate high-energy neutrino beams for the Deep Underground Neutrino Experiment (DUNE) and the Long-Baseline Neutrino Facility (LBNF). As part of this project, the design and optimization of the cryomodules play a crucial role in achieving efficient operation. In this thesis, the focus is on the High Beta 650MHz (HB650) cryomodule, which was chosen for detailed analysis due to its relevance during the research period. The aim of this study is to estimate the heat loads, and determine the temperatures of key components during cool-down.