GCHP system designers and contractors working in colder climates need to protect the heat transfer fluid from freezing if the temperature of the GHX is expected to drop below about 40°F (5°C). Adding antifreeze to water increases the density and viscosity of the fluid and changes the flow characteristics of the fluid. As the fluid is cooled by the heat pumps the density and viscosity increase and can result in temporary failure of the system.
If you're considering installing a GCHP system in you home, congratulations...it's one of the most efficient systems you can find to heat and cool your home. It can also provide domestic hot water or heat a swimming pool. But before you start asking for estimates or quotations, it's in your best interest to ensure your home is as efficient as possible.
I've spent the last couple of weeks in Australia. Probably the biggest reason I'm here is the increase in the cost of electricity in Australia in recent years. Since 2007, the price of electricity has increased more in Australia than most other places. The main reasons for the increase include increased use of household appliances (air conditioning, entertainment), capital cost expenditures to improve distribution grid, and the addition of a 9% carbon tax. How can the GCHP industry help?
There is a common misperception that the capacity of the heat pump is what determines the size of the GHX. Many times I’ve heard a contractor say that he installed a “5-ton loop” (17.5 kW loop) for a home. What if he installed a 6-ton (21 kW) heat pump in the home rather than a 5-ton (17.5 kW)…would the size of the GHX have to be increased? Or if a 4-ton (14 kW) heat pump was installed, would a smaller GHX work as well?
The Sydney Opera House is probably one of the most recognized buildings in the world. I finally saw it for my first time a few days ago during my visit to Australia to teach the IGSHPA Accredited Installer Course and the Certified GeoExchange Designer course at the U of Melbourne. I didn't realize the Mechanical Engineering firm (Steenson Varming) designed a revolutionary system, using water from Sydney Harbour to cool and warm the facility.
The first IGSHPA Accredited Installer course was completed at University of Melbourne, Australia today. A class of 19 including several graduate students from the School of Engineering Geotechnical Engineering Department, a number of HVAC contracting and design forms completed the course. This is the first time the course has been delivered in the southern hemisphere.
The Oasis Leisure Centre in Kalgoorlie Boulder, WA, is now heated by one of the largest closed loop geothermal systems in the State. The system is unique in a couple of respects. Even though the facility is in a hot climate, with summer temperatures as high as 46°C (115°F) and deep earth temperatures at 23.5°C (74.3°F), the building requires more heating than cooling. There are two reasons for this:
According to the Energy Efficiency Market Report published by the International Energy Agency, "investments in energy efficiency provide such massive savings that the energy saved actually completely eclipses the energy generated by most forms of generation. This “first fuel” is incredibly important to the world’s efforts to reduce fossil fuel use and carbon emissions and should be focused on even more, the new report argues."
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.