The new geothermal system serves Tinker Hall, the university’s largest student residence.
The critical difference between a geothermal system and a standard residential heat pump unit is that the former uses the ground as a heat exchange medium while the latter utilizes air. A geothermal system takes advantage of the stable, nearly constant temperatures of the earth below the frost line; an air source heat pump becomes much less efficient as air temperatures become more extreme. The result is improved temperature control, better indoor air quality, and lower energy costs.
A geothermal system offers other benefits. It does not require a noisy chiller or cooling tower. Geothermal heat pumps have fewer moving parts and can last 20 – 25 years, while the life of a chiller is as little as 15 years and a high-efficiency boiler can last just 10 years. Geothermal wells need much less maintenance than both steam and chilled water lines and are expected to function 50 years or longer.
The number of geothermal wells originally planned for this project was scaled down, thanks to the fact that the Hollins campus has “great dirt” that creates a high level of thermal conductivity. This helps increase the performance of the system and also helps lower costs and land disturbance.
The installation of the geothermal system at Tinker Hall is a big step toward Hollins’ goal of carbon neutrality.