Geothermal Heat Exchangers (GHE) in Ground-Source Heat Pump Systems
Geothermal Heat Exchangers (GHE) in Ground-Source Heat Pump Systems
Primary researcher: Mitchell Caister
This research focuses on heating, ventilation, and air conditioning (HVAC) systems. The specific focus of this research is geothermal heat exchangers (GHE), which are used in ground-source heat pump systems. Geothermal heat exchangers most commonly use a series of boreholes in the ground with water being pumped through them (see Figure 1). This allows the ground-source heat pump to utilize the free heating and cooling capability of the ground, resulting in energy savings. The goal of this research is to create and optimize an analytical model which can be used to simulate GHEs at any time frame and design configuration. This model will improve on the current work by:
- Increasing the accuracy of simulations by implementing a more sophisticated finite-difference model for modeling the heat exchanger;
- Reducing simulation times through making valid simplifications to the model of the ground;
- Improving the applicability of the ground model by expanding it to larger heat exchangers with multiple boreholes.
- Creating an optimization algorithm for this improved model, which will allow designers to input their design requirements, and will yield design parameters that will minimize installation cost.
This research will allow engineers to design buildings with more efficient and sustainable HVAC systems through more accurate modeling, and optimization for cost. Ground-source heat pump systems are fully electric, which will result in lower scope 1 greenhouse gas emissions when compared to traditional natural gas systems. However, these systems have a relatively high up-front cost, thus, optimizing the design for cost minimization will allow engineers to create HVAC designs that are sustainable, energy-efficient, and affordable.
Figure 1. Geothermal heat exchanger schematic. Source: U.S. Department of Energy
