The current challenges posed by climate change create a need for new technologies based on advanced functional materials. Rising global temperatures increase the frequency and intensity of extreme weather conditions. These harsher climate patterns lead to a higher demand for cooling. As a result, energy consumption continues to grow, with air-conditioning (AC) systems making a major contribution [1]. This rising demand for AC systems places strong pressure on existing energy resources. This situation highlights the need for more reliable and energy-efficient cooling technologies. Conventional vapor-compression systems cannot meet these needs without raising emissions further, which encourages the development of cooling alternatives. Novel AC systems are based on the so-called magnetocaloric effect. This effect describes the change in temperature in a magnetic material caused by external magnetic fields. Current research focuses on improving the mechanical and thermal properties of these materials, including Heusler alloys [2]. These alloys are strong candidates since their magnetic and structural responses can produce large temperature changes, making them attractive for solid-state cooling. To explore these effects in a controlled and quantitative manner, a detailed numerical analysis of the magnetocaloric behaviour using a variational phase-field formulation is conducted. The model follows a time-dependent Ginzburg-Landau equation and includes elastic, magnetic, and thermal energy effects. Within this framework, these contributions define the free-energy functional that governs the martensitic and austenitic phase transformation [2]. The magneto-mechanical coupling is described via the micromagnetic theory including linear elastic contributions [3]. Together, these components form a consistent multi-field framework for modeling magnetocaloric materials. The study clarifies the interaction between magnetic and structural transformations in these alloys and supports the development of efficient magnetocaloric materials for sustainable cooling.