Abstract
Geothermal energy, defined as heat from the Earth, is a statute-recognized renewable resource. geothermal resources are available 24 hours a day, 7 days a week. While the carrier medium for geothermal electricity (water) must be properly managed, the source of geothermal energy, the Earth’s heat, will be available indefinitely. The principle of a heat exchanger is to transfer heat from the primary to the secondary side through a heat-transfer plate that separates the flows. geothermal heat exchangers are used for heating, cooling, condensing, evaporating and the recovery of process heat. Geothermal energy is a renewable form of energy that can be used for electricity production or can be utilized for heating and cooling applications. The latter is commonly described as low temperature, shallow geothermal energy use where ground resources up to approximately 400 m below the surface are used. To do so, different types of ground heat exchangers (GHEs) are buried underground to exchange heat with the surrounding soil. Based on installation depth, systems are commonly divided into horizontal systems that are installed just below the surface in excavated trenches and vertical systems where boreholes are drilled to larger depths and grouted. In between, a group of shallow systems up to the depth of 30 m in form of energy piles or large diameter helical coils exist. Geothermal systems can also be classified as open or closed systems. In an open system configuration, air or water from the surrounding flows through a heat exchanger, exchanging heat with the underground, and is then used in heating, cooling, or ventilation systems. In a closed configuration, secondary working fluid circulates in a heat exchanger in the closed-loop and exchanges heat with the underground; therefore, only heat transfer is accounted for.

Contents
Title page
1. Introduction
2. Market and Legislative Considerations
2.1 Factors
2.2 Heat exchanger specifications
3. User Considerations
4. Design Development
4.1 Horizontal Heat Exchanger Configurations
4.2 Vertical Heat Exchanger Configurations
4.3 Shallow Ground Heat Exchanger Configurations
4.4 Direct Expansion Systems
5. Conclusions
6. Further Work
References