Knowledge engineering techniques are becoming useful and popular components of hybrid integrated systems used to solve complicated practical problems in different fields. Knowledge engineering techniques offer the following features: learning from experience; handling noisy and incomplete data; dealing with non-linear problems; and predicting. This paper presents a knowledge engineering case study by constructing a chromosome of Energy Decisional DNA. Decisional DNA, as a knowledge representation structure, offers great possibilities on gathering explicit knowledge of formal decision events as well as a tool for decision making processes. In this case study, several Sets of Experience of geothermal energy were collected for the construction of a geothermal chromosome within the Energy Decisional DNA. This chromosome is then implemented in an ontology model aiming to be used for predicting purposes. Thus, it enhances different systems with predicting capabilities and facilitates knowled...