We have mapped the climate of the US from a passive solar point of view, using climate data collected over 30 years from 250 cities.
Passive solar climate mapping differs from other forms of climate mapping because we are primarily concerned with the relationship between solar radiation, heating degree & cooling degree days.
Our analysis method was to use the data to firstly rate the building heat loss characteristics of each location & then combine this with the global radiation data to rank each of the 250 data sites. The sites were then grouped according to their rankings to create 11 zones. These zones provided a basis for performing a passive solar heating design & range from 'Very Hot & Very Sunny' to 'Very Cold & Very Cloudy'. Within the 11 zones there were some sites that had different passive solar cooling requirements. We therefore split the 11 zones into subzones, as required, to create a total of 17 individual design locations.
Our design method is based on performing energy use calculations, using “RunSUNREL” Building Energy Simulation software developed by the National Renewable Energy Laboratory, on 3 models in each zone for each house plan.
The first model is a standard house with glazing distributed evenly around the perimeter, a 12" overhang, standard wall & ceiling insulation. It is assumed that the house is new & is typically heated & cooled during the afternoon & evening to maintain the indoor temperature between 70 & 75 deg F. This gave us a basic energy use expectation for each zone.
We then modified the standard house to create the idealized passive solar model. This model was used to refine the glazing distribution, the overhang & under floor insulation so as to maximize the energy saving.
It is not always possible to apply the optimum glazing distribution to all of the house plans & still achieve balanced & comfortable architectural spaces, so we have applied the design results to the house plans as far as practicable.
We then performed an analysis of the actual passive solar house & compared its energy use, in each of the climate zones, with the standard house. Thus we were able to calculate the percentage energy savings noted with each of the house plans.
The energy calculations are available to our Clients on request.
........................THE BEST FORM OF ENERGY EFFICIENCY IS TO USE THE FREE ENERGY OF THE SUN.........................