This chapter addresses the problem of modeling of emotions which is important for integrating emotional intelligence into virtual agents. In this chapter we present a virtual agent which plays a role of a technical support engineer and interacts with human user to answer questions about a complex device. We show some theoretical background and basic models of formalizing emotions along with comments about their usability in our work. We present a multi-layered system of processing of emotional information which is developed according to the modern theories and allows us to realize concurrent and mutual causal processing of different types of emotional information. We also show an evaluation methodology which we use.