Warming With Windows--Passive Solar Primer


How solar energy is used in houses

Type Collector Efficiency Collector Cost Maintenance Primary Purpose/ Applications Energy Storage Storage cost
Photocells (usually on rooftop) low (less than 20% of incident solar energy) high medium to high Generates DC electrical power which must be converted to AC power for most home applications. Requires batteries. In some cases the excess energy can be fed back into the power grid. high for batteries. medium for feed back to grid
Active  Thermal Collectors (usually on rooftop) high (depends on many conditions but can exceed 50%) moderate to high medium to high Water and space heating. Uses pumps or blowers to circulate water or air from the storage system to the collector and back. Water tanks or other thermal masses such as gravel filled containers or phase change materials. medium
Thermo Siphon  Thermal Collectors (usually on rooftop) high (depends on many conditions but can exceed 50%) moderate low Water heating. The tank is placed above the collector in an attic or on a roof. No pump is required. Water tank low to medium
Passive Solar Design (whole house is the collector) high (depends on many conditions but can exceed 50%) low low Space Heating Heavy building materials such as concrete slabs, brick or stone walls. low to medium


Passive Solar: In a passive solar house, the house itself acts as the collector and storage system for solar energy. Properly designed, passive solar features will warm a home in the winter and lower air-conditioning bills in the summer without significantly adding to the home's original cost or ongoing maintenance.


5 Key Features of Passive Solar:

  1. Orientation: South Facing Windows
  1. Overhangs: Properly designed these shade in summer but not in winter
  2. Thermal Mass: Can be a concrete slab (usually covered with ceramic tile), a brick or stone wall, and/or water containers. Properly done, thermal mass adds very little expense to a house.
  1. Heat Distribution System: Generally, air or some other fluid has to be moved around the house to create a uniform temperature.
  2. Insulation: Passive solar is a gentle form of warming. It's not available at the touch of a switch and even when available will usually not supply heat as fast as a typical central heating system. The percentage of a home's heat supplied by passive solar depends heavily on the quality of the insulation.


Assessment -- Investigation of a solar home design

Specifications: Use Google Sketchup to design a 3D solar home with the following features:

Drawing 1: Shows how the house will look. Surfaces must be textured and windows transparent. Furniture and landscaping is not required. Thermal mass must be apparent and positioned so that the sun shines on it. The orientation of longest wall and majority of windows should be to the South. Overhangs must be included and properly designed to block the sun in the summer and let it through in the winter. This drawing includes:

  • a living area
  • a kitchen--must have a sink, stove, and refrigerator
  • a bathroom--must have a tub, sink, and toilet
  • two bedrooms

Drawing 2: has no furniture or textures but shows the dimensions on the walls, roof, and floor plan required to build the house

  • all the needed dimensions must be shown


Deliverable: Two 3D Sketchup file stored in your student drive labeled Passive Solar House 1 <your name> and Passive Solar House Dimensions <your name>.

Work Group: individuals.