Systematic analysis with comparison of a chiller plant with horizontal underground heat exchangers and cooling tower

Using an underground heat exchanger as an alternative to a wet cooling tower can offer several benefits, particularly in terms of energy efficiency and environmental impact. The choice between an underground heat exchanger and a wet cooling tower depends on specific factors such as the scale of the cooling or heating application, local climate conditions, and economic considerations. This study aims to compare the utilization of an underground heat exchanger as an alternative to a wet cooling tower for cooling purposes. Both the underground heat exchanger and wet cooling tower provide cooling water to be used in vapor compression chillers. The comparison is conducted on technical, economic, and environmental grounds. The research is focused on the Mashhad region, which faces limited water resources and high cooling demand during summers. Faculty of Engineering, Ferdowsi University of Mashhad is selected as a case study. Both methods of producing cooling water, along with the refrigeration cycle, are modeled and simulated to calculate and compare energy and water consumption. The findings reveal that using the underground heat exchanger results in a 14 % reduction in energy consumption and eliminates water consumption altogether. This is particularly significant considering that the current watercooled compression chillers consume approximately 1.95 cubic meters of water per square meter of the building daily. The economic feasibility of implementing the underground heat exchanger is assessed, and the payback period is calculated to be 1.73 years when compared to the existing water-cooled compression chiller system.