As the final pieces of our "net zero" home come together it becomes more and more apparent that this house is ready for solar panels!! Looking at the pitch of the roof you can see that solar panels will be a great addition. The passive solar design of the home will take advantage of the climate to maximize solar exposure and distribution after solar panels are added to the home's roof.
The "net-zero" home in Durham that we have been working on is not only trying to reduce their expenditures later by utilizing energy saving construction but they are also saving money during the framing process by using advanced framing techniques. Advanced framing techniques (also called Optimum Value Engineering) start with a well thought out framing design that considers common lumber and sheet sizes. This reduces waste, minimizes cutting and consequently material and labor costs. Advanced framing also leaves more room for insulation and eliminates cold spots, thus making the house less expensive to both heat and cool. This home has given us an opportunity to try out a new product, Home Slicker. You may have seen a home under construction and noticed that the home was being wrapped with black paper or Tyvek. This is done as an added barrier to keep moisture out. We'd originally planned on creating channels for rain to drain behind the siding with wood strips until we found the Home Slicker product. In the picture below you can see the channels allowing for drainage built right in!
One of the most cost effective ways to install a radiant heating system is to embed the tubing in a concrete slab. Here you can see the hydronic lines over the insulation boards. After the lines were placed it was time to pour the concrete.
The concrete will be smoothed and prepared for a polished finish. A polished concrete floor is a gorgeous alternative to other floor coverings allowing our homeowner to make the most of their radiant floor heating system.
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.