Although GeoExchange has been done before, what is unique about TELSEC’s proposal is that they will install 2 sets of piping in each of 100 holes. One set of piping will be used for the heating and cooling of the building, the other will be used to circulate a fluid through a total of 200 PVT panels. PVT allows for both solar thermal output and photovoltaic output. The goal is to increase the amount of thermal load that can be extracted from the ground. Traditionally, in a multi family building in a colder climate such as ours, the heating load is about 3 times the cooling load. For GeoExchange to be effective, we need to do as much as we can to balance out the heating and cooling loads to keep the ground temperature in balance. Trying to have GeoExchange carry the full heating load when cooling isn’t equal to the heating load will eventually freeze the ground. At that point the GeoExchange system fails and it is virtually impossible to recover it without injecting a tremendous amount of heat. By adding solar thermal heating to the holes we hope to achieve a far better balance between heating and cooling. A solar thermal system was installed at Drake Landing at Okotoks years ago. Over time the solar thermal panels situated on 52 homes has increased the ground temperature of their heat sink to 75-80 degrees Celsius which is sufficient to heat the 52 homes during the winter. Our approach is much simpler but the concept of building up ground heat during the warm seasons is the same.
