Thoughts on Solar Energy Design and Construction

article image
The installation of a solar-heating system still demands for most people a significant investment in time and material.

As an outgrowth of our work on the Grieve solar heated home, a few of us here in Prescott, Arizona have formed a company called Arizona Sun works. One of our main objectives is to demonstrate that solar heating is possible now, and can be achieved without an accompanying 30-year mortgage. Members of Arizona Sunworks are presently building a house that will utilize the Thomason water/rock solar-heating system and a solar heated adobe shop. The shop will be the base from which we’ll construct our own solar-heated adobe homes.

Solar Energy Design and Construction

Our ground rules for design and construction are:

  • Build small.
  • Do your own work.
  • Allow available local materials to determine the type of construction and heating system you use.
  • Build in stages. Building small-in phases-allows us to experiment, live with, and perfect alternative systems and skills while minimizing our capital requirements.

The installation of a solar-heating system still demands for most people a significant investment in time and material. It’s important, then, for anyone planning such an installation to evaluate his or her particular situation so that he or she may choose the right system for the application at hand.

Before starting construction of a solar heater, a person should be familiar with every design that’s available, should understand the climatic conditions of the area in which he or she lives, and should know the heat load requirements of the building being fitted.

When an existing structure is retrofitted, it must first be evaluated for thermal efficiency and, if necessary, reinsulated. (Anyone who attempts to use “free” solar energy to warm a house that’s a thermal sieve will be very disappointed.) Walls and roof should have a total thermal resistance of not less than 15 (one-fifteenth of a Btu passing through one square foot of wall every hour for every one degree Fahrenheit temperature difference between inside and outside). The building should be as tight as possible to minimize air changes. Perimeter foundations should be insulated, and windows double glazed or covered with heavy fiberglass drapes or movable insulated shutters.

If you’re building a house from the ground up, don’t make the mistake of considering solar systems as an afterthought To be most effective, solar-heating and cooling systems must be so thoroughly integrated into a structure that its designer is required to develop a new awareness of the natural forces that determine the building’s form.

Although solar heaters currently cost more than the “conventional” systems they replace, over 40% of the new units’ cost goes into labor. Once the new systems are mass-produced and become conventional in their own right, this cost difference should narrow. Even at today’s prices, however, a good solar heater which should last at least two decades will pay for itself in eight to twelve years.

The federal government — with the Solar Demonstration Act of 1974 — has allotted sixty million dollars over the next five years for the development and demonstration of solar hardware and systems. Although this will be just the beginning of a large government monetary infusion to the field, indications are that such funds will go mainly to big industry and universities.

This is unfortunate since, to date, it has been individuals — such as Harry Thomason and Steve Bear — who have developed the present state of the art. Free exchanges of information — exchanges which include individual experimenters working “without portfolio” — will be critical in the future development of solar hardware and related skills and should be suitably supported by any available funds.