Design and Development of an Additively Manufactured Geothermal Heat Exchanger for Improved Efficiency and Easy Installation

Effective system energy management and cooling is critical for a range of increasingly complex systems and missions. Various industries and agencies seek technologies to use energy more efficiently in various applications, and thereby increase system energy efficiencies in future advanced energy systems. There has been an increasing interest in exploiting the use of additive manufacturing in developing nontraditional energy conversion schemes. Meanwhile, wind power and solar power systems have become part of common knowledge and conversation over the past few years. While these provide excellent sustainable options of energy production, geothermal energy systems are just as efficient and economical. Solar and wind energy collectors are also site specific. On the other hand, the geothermal systems do not take up buildable ground level space nor are they location or climate specific. The earth has a generally constant temperature throughout the year which can be used in geothermal systems to benefit all sites. If all geothermal resources were combined, enough energy would be produced to provide all of the electricity needs in the United States. However, conventional geothermal system requires the relatively complex installation process and can potentially be cost prohibitive to many potential users.

In this study, an additively manufactured heat exchanger was designed and developed fo resolve that issue. The heat exchanger can be integrated with a conventioanl geothermal heating and cooling system for improved efficiency and easy installation. A customized geothermal heating and cooling loop was designed and developed for testing the efficiency of the heat exchanger. Within this proposed system, this additive manufactured heat exchanger is designed and fabricated to improve it efficiency and easy installation with minimal tools needed. This new design eliminate the need of excavation of the soil and installation of long tubes as conventionally required for geothermal system. This new heat exchanger was designed using CREO software and fabricated using an EOS M280 direct metal laser sintering system at University of the District of Columbia. It is then integrated with a heat pump to exchange heat between a constant temperature of water bath circulator and a water heat sink. A prototype system was designed and constructed, which allowed the direct assessment of its performance. The performance of the heat exchanger is studied using COMSOL software to assess its heat transfer performance. The results have shown a significant improvement in its efficiency. It has shown the promising application of metal additive manufacturing technique in improving the efficiency of existing energy harvesting applications.