General House Description - II

Above is a quick basic floorplan sketch of my house. I think it will help visualize a number of the passive solar design concepts that I incorporated into my house design and that I have described in the last post and will describe in this one. I will add some pictures of the house in proceeding posts to further help in this visualization and understanding. I also plan to post more detailed floorplan sketches of the house, its systems, future planned additions, possible modifications, and anything else that I might want to get feedback about from interested readers. Now I will describe some of the other passive solar design principles I incorporated into my house design which I did not mention in my previous post.

· The south wall of the house faces within a 10% deviation of true south to obtain close to 100% solar benefit. With the large number of big windows on the south wall, the sun’s low winter arc over the sky enables the house to meet most of its winter heating needs through solar radiation. No trees or other obstacles in front of the south wall block this winter sun.

· Behind the north-facing wall are a number of mature pre-existing trees and a number of younger trees that were planted, as well as a rock wall and numerous large bushes and vines, which all help to block and weaken cold, harsh winter winds coming from the north. I also plan to build a greenhouse behind the house which will have an even greater impact on attenuating these cold winds.

· In the summer the virtually overhead position of the sun allows for very limited amounts of solar radiation to pass through the windows, due both to increased solar radiation reflection and decreased solar radiation due to the sun’s angle relative to the vertical glass. To completely block this summer solar radiation from entering my south windows, I plan to build a two meter wide solar room all along the face of my south wall. This solar room will incorporate ‘roof overhangs’ in the form of PV panels. I will also attach onto this solar room exterior rollable solar shade cloth to block unwanted summer solar radiation not only into the home’s windows but also into the solar room.

· The solar room will act as a solar air heater in the winter to provide extra solar heat for the house. By simply opening the doors or windows during sunny days, a convective air flow will be put in motion whereby hot solar room air will flow into the home and cooler floor level air will be sucked into the solar room. This solar room will also act as an extra insulation layer for my south wall and its windows. Futhermore, it will act as an air-lock entry to both of my home’s entrance doors - a rather large air-lock. And this same solar room can be used at certain appropriate times of the year as a solar chimney to create a structured flow of air in the house where hot air in the solar room rises up and out of top ventilation openings in the solar room thereby creating negative pressure in the house through the open doors and windows. This negative pressure in the house then sucks in cooler air through vents and windows from the sun-protected back of the house.

· Operable windows and their strategic placement allow for the channeling and control of cooling breezes throughout the house. These windows are opened and used for this purpose during appropriate times of the day and year.

· An adequate balance between glazing area and thermal mass volume was established. Over-glazing and under-massing can result in the interior overheating due to excessive solar radiation while under-glazing and over-massing can result in the opposite. Moreover, excessive glazing of wall space can lead to excessive heat loss at night.

· The exterior of the house is a traditionally south-European white. This is to reflect away much of the sun’s unneeded summer radiation, thereby helping to prevent the exterior walls becoming hot and transferring that heat into the home at night through thermal lag conduction. The terrace floor is also painted white. I plan to add a layer of ceramic-based radiant insulation paint to the exterior surfaces in order to reflect away close to 100% of this summer radiation. Much of the interior walls’ surfaces are also white to help distribute daylight throughout the home. However, the south half of the home’s floors are a dark color, as are a number of its interior partition walls, to better absorb winter solar radiation.

· I made sure not to oversize the back up heating system for the house, a small wood-fired Finnish soapstone high-efficiency masonry stove, which is designed to heat only the south half of my home. By undersizing it, I avoid unnecessary and frequent interior overheating and, thereby, wasted fuel. This is important because besides the solar room that I will add for extra winter solar heat, I will also eventually add an active solar system to collect solar heat and transfer that heat to the north half bedrooms and bathrooms where they will flow through baseboard fin heaters specially equipped with appropriate phase change thermal mass.

· To help block summer solar radiation on my east and west walls, I will use vegetation. Next to my east wall I am growing a decidous low canopy almond tree that will block much of the summer’s solar radiation. On my west wall, I plan to install vertical trellising to grow thick tall vines which will block almost all solar radiation. I may also put some vines on the east wall. These plants not only block the sun but also help keep the wall surface cooler through the effects of evapotranspiration and help maintain the walls’ natural air insulation barrier.

I see that once again my typing has gone uncontrolled. This post is quite long. I will leave it as is. I have tried to be brief so the descriptions are not what they could be, and I may have left out a number of passive solar design principles that are or will be incorporated in my house. Once again, I entreat whomsoever has a comment they may wish to make to please do so for I will be greatly grateful.