Swedish architect Anders Holmberg hopes to design a passive solar home for all. In Stockholm, Sweden, he hopes to find his answer. There, Holmberg has designed four highly insulated passive homes that are a testament to simplicity, style and small footprint.

For starters, the homes are constructed from styrofoam blocks lined on either side with a layer of plywood, otherwise known as structurally insulated panels (SIPs). The homes also use solar heating for space and water, as well as recycle waste heat from appliances and other devices in the home.

That’s perhaps the most innovative concept used for these homes. Recycling waste heat is not unheard of (see heat recovery ventilators), but reusing heat from appliances and devices within the building is a practice most often seen on the commercial or industrial scale here in the United States. Given the amount of heat that most appliances produce, there is great potential for recycling heat in the modern home. (more…)

Passive solar heating is taking on labyrinthine proportions in order to save money and energy at NREL’s upcoming Research Support Facilities (RSF) in Colorado. The new, ultra energy efficient office building will consist of two lengthy wings, connected in the center by a lobby and conference area, each resting directly above a dark labyrinth. No it is not designed to confuse bull-headed beasts, nor house Bush-era members of the Department of Interior, but a labyrinth with a much more benign and energetic purpose.

This “solar” labyrinth will collect and store energy to help heat or cool the building above. It is a huge exercise in capitalizing on the thermal properties of concrete, as well as the valuable heat generated by the sun (especially in Colorado where winters are cold but relatively sunny). The labyrinth is comprised of several staggered concrete support walls beneath the massive concrete floor of the RSF itself. You might call it a sort of shallow basement, but one that will trap warm air, which in turn will slowly pass through the concrete floor throughout the night and into the morning to ease heating loads for the offices above.

The Solar Formula

The sun enters the equation by way of a transpired air collector — a metal sheet with tiny, well-placed holes designed to draw air through. The solar heated air will be drawn by fans down into the labyrinth through air vents designed into the buildings’ stairwells. There it will embark on its slow, warming journey back into the building.

In the summertime, cool air at night will be drawn down into the labyrinth where it will slowly journey upwards to help keep the air cool and ease heating loads. The S-curves of the basement will force the air to linger awhile before escaping through vents, maximizing the amount of energy (cooled or heated) retained by the building itself. (more…)

Of the five elements of passive solar design, two deal primarily with materials. These are the absorber and thermal mass and are often two characteristics of the same material. The absorber represents the surface of the material (e.g., masonry wall, water wall, floor, etc.). The thermal mass retains or stores the heat from sunlight. It is the interior, the substance behind that outer, absorbent surface.

Glass, of course, cannot be ignored as a passive solar material. But the effectiveness of a window in passive solar heating has as much to do with aperture – or placement relative to the sun – as it does with material. All windows, however, are not created equal. Windows that are double- or triple-glazed with low-e coatings and efficient frames are best for passive solar design.

There are three essential materials behind passive solar design: masonry material, glass, and water. Furthermore, there are also three ways to harness solar energy passively: direct gain, indirect gain, and isolated gain. Which materials you use, and how you use them, will depend largely on which approach you take. (more…)