In addition to the work on the geothermal heat pump we have been getting started on the foundation of our net-zero project in Durham. The foundation for this project has included a combination of 10" poured concrete walls (where significant retainage is needed) and standard concrete block where the grade is less severe. The penetrations in the poured concrete wall show the large opening where our mechanicals, (electric, plumbing, radiant piping, and pvc hvac supply ducts) will all be installed under the slab.
An exciting and energy/cost saving feature of our future "net-zero" project in Durham is the geothermal heat pump.
Geothermal heat pumps are able to heat, cool, and, if so equipped, supply homes and buildings with hot water. A geothermal heat pump system consists of a heat pump, an air delivery system (ductwork), and a heat exchanger—a system of pipes buried in shallow ground. In the winter, the heat pump removes heat from the heat exchanger and pumps it into the indoor air delivery system. In the summer, the process is reversed, and the heat pump moves heat from the indoor air into the heat exchanger. The heat removed from the indoor air during the summer can also be used to provide a free source of hot water. Source: U.S Department of EnergyA typical closed loop system is installed horizontally or vertically, as seen in the images below. Source: U.S. Department of Energy With this home we were able to take advantage of a natural depression in the lot to install a horizontal loop geothermal "slinky." This gets the piping down about eight feet without the extensive costs associated with trenching for vertical or horizontal loops.
We have just started a new project in Durham that we are very excited about! The ultimate goal is a net-zero home. "Net Zero" Energy building is a growing trend. With the rising costs of traditional fossil fuels as well as the increasing interest in the environment a home that can function autonomously from the energy grid supply is an attractive option. Given current costs of photovoltaics a true "Net zero" building can be an expensive and complicated endeavor. Many homeowners are instead opting for a "near-zero" home. A "near-zero" home is a home that uses very little energy and takes advantage of many energy efficient building techniques.In this case, the home will be prepped to be connected to photovoltaics down the road when the costs come down. This project will feature a geothermal heat pump and HVAC unit, hydronic radiant heat concrete floors, open cell spray foam insulation, closed cell exterior rigid foam insulation, closed cell spray foam insulated roofing, a passive solar design and energy star program appliances. We are excited to be starting this project. Having a gorgeous wooded site to build on isn't bad either!