If you lived in Canada or the northern States you're probably not looking forward to another winter after the record cold and snow we experienced. Winnipeg, MB had the coldest winter since 1898! That erased most of the memories we had from only two years earlier when we had one of the warmest years on record. What happens to a GHX when we go through extreme weather events like that?
Will they work during extreme weather events and keep us comfortable...or will they quit working and rely on a conventional system to keep you comfortable?
The graph shows the average temperatures of a horizontally bored GHX in a 45,000 square foot (4,200 m2) office building located in Winnipeg. The system has been in operation since 2009. The GHX was designed to operate at a minimum temperature of 35°F (2°C) in winter and a maximum temperature of 85°F (30°C) in summer. In 2012, one of the warmest winters on record, the minimum temperature only dropped to about 45°F (72°C), while 2 years later, during the coldest winter in 116 years, the temperature dropped to 35°F (2°C) .
The summer GHX temperature climbed to about 83°F (28°C) during the hot summer of 2012, while in the summer of 2013, a cool summer, the temperature only climbed to about 73°F (23°C).
The GHX design was based on an 8,760 hour energy model. The thermal conductivity and diffusivity of the clay the GHX was buried in was tested using a Decagon KD2 Pro test meter.
The graph clearly shows the GHX operating temperature is impacted by the weather. While this building was modeled using the last 20 years average weather data, what will happen to GCHP systems if climate change continues to have an impact on the temperatures we see in the future?
In my blog I'll be expressing my opinions about what I've the learned about ground coupled heat pump (GCHP) systems over the last 30 years. I've been very fortunate to work with many interesting people who are passionate about this technology...engineers, geologists, mechanical contractors, drillers, excavation contractors...in different parts of the world. I've learned a lot from them and will be using this forum to pass on some of the things I've learned and feel are important. Please feel free to use this information if you feel it's worthwhile...hopefully you can avoid some of the same mistakes I've learned from.