Low-Enthalpy Geothermal Systems

Energy consumption has increased as a result of two main factors: the economical recovering of industrialized countries after a decrease in energy demand and the economical emergence of countries such as China and India. Geothermal energy is one of the alternatives to ensure sustainable development, representing a clean, free, renewable energy available everywhere. The use of subsoil as a thermal energy reservoir has always been an opportunity. When the heat pump became a consolidated method, geothermal energy became cost-effective. In this method, the subsoil is used to take heat during winter and to release heat during summer, with a sustainable cost. The growing awareness and popularity of geothermal (ground-source) heat pumps have had the most significant impact on direct-use of geothermal energy. The annual energy use for these units grew 2.45 times at a compound annual rate of 19.7%. The installed capacity grew 2.29 times at a compound annual rate of 18.0%. This is due to better reporting and to the ability of geothermal heat pumps to utilize groundwater or ground-coupled temperatures anywhere in the world. This chapter will present a summarized description of the different ground source heat pump systems and a discussion on the efficiency of this equipments and its environmental impact, showing that ground source heat pumps can be an effective, ecological and low cost alternative for heating and cooling applications.