**5. Conclusions**

Although the assembly is not generally considered in the optimization of thermoelectric generators, the present chapter has demonstrated that it is an aspect that cannot be forgotten since it deteriorates the performance of generators. Thus, the assembly needs to incorporate thermal interface materials that counteract microscopic imperfections, being graphite sheets the most recommended one between the studied. In order to ensure this microscopic contact and reduce the temperature drop that appears in the interface, it is also important to apply some pressure to the assembly. The easiest way to achieve this is the use of screws. Pressure measurement films have shown that each module needs to have its own tightening. Assemblies that share this tightening can cause a contact in only some parts of the module. However, the implementation of these screws has a counter effect: they represent a thermal bridge themselves and part of the heat is lost through them. Therefore, the insertion of nylon rings is recommended. The other important source of losses due to thermal bridges occurs between the heat exchangers, since the distance between them is too small. Placing an insulating material between the exchangers slightly reduces the losses, but it is better to increase the distance between them with the aid of a conductive heat extender and insulate with acrylic wool. Nonetheless, if this material is not added, air has demonstrated to also be a good insulator, cheaper but which leads to a less precise assembly.
