A new IKEA store in the Denver area will employ 500-foot-deep holes in its cooling and heating system. The 130 holes will be just below the store’s parking garage. Temperatures in the holes hover around 55 degrees year round, so air inside them can be pumped up into the cooling and heating system to reduce energy costs by up to fifty percent. Nationwide, geothermal has the potential for saving billions of dollars in energy costs.
Opening in 2011, the new Denver store has the National Renewable Energy Laboratory as a partner in the design and construction of the geothermal energy components. The system works basically as a series of pipes placed in the holes containing a liquid like water which takes on the temperature of the soil walls of the holes and then is transported back up to surface level. If the temperature at the surface is hot during summer, the 55 degree water is used for cooling, and if it is winter, it is used for warming.
Erin Anderson, geothermal analyst said, “We’re trying to determine what the temperature is all the way down as a way to achieve a comfortable temperature in the store. We have this ground that is pretty steadily cooler in the summer when you want cool air and warmer in the winter when you want warm air.” (Source: NREL.gov)
Currently they are in the initial phase of determining the project’s infrastructure in order to make it a stable system. One might assume the demand for heating in a Colorado winter would be greater, but there is also a high demand in winter for cooling, because the store’s interior temperature is raised significantly by the high volume of people. Cooling and heating a 415,000 square foot two-level building requires a great deal of energy so the engineers are trying to take advantage of reusing energy. For example, some warm air inside the building will be directed at a parking lot floor which is a very large mass of concrete in order to melt ice forming on it.
Digging the 500 foot holes requires four to five hours at a time, if everything goes well. If there are difficulties, one hole can take all day. The cost of drilling is expected to be offset by energy savings fairly early in the store’s life. Also, the geothermal energy system is expected to function well for as long as the building is in use. The hope for the Denver area store is that it will be a model for other commercial geothermal projects.
NREL works with academia, non-profits, and the private sector to research and implement alternative energy projects. They recently launched a competition for college students working on geothermal research with $100,000 in awards.
Image Credit: Gretar Ívarsson, geologist at Nesjavellir. Photo is not of the actual Colorado site, but is from Iceland and meant to represent geothermal energy in a generic sense.