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1947-48 Theatre Catalog, 6th Edition, Page 421 (407)

1947-48 Theatre Catalog, 6th Edition
1947-48 Theatre Catalog
1947-48 Theatre Catalog, 6th Edition, Page 421
Page 421

1947-48 Theatre Catalog, 6th Edition, Page 421

Solar Energy Utilization for House Heating

Sun's Radiation Can Be Captured for Uses

In Heating and Possibly Air Conditioning


The accompanying discussion of solar heating is a condensation of Report PB 25375 of the Ogice of Production Research and Development of the War Production Board, submitted in fulfillment of Contract WPB-100, and deals only with that portion of the report covering the construction of various experimental solar heat collectors and the general results and conclusions derived from the investigation.

For the technical details, mathematical formulae, and other details by which the investigators arrived at their conclusions, the reader is referred to the original report, obtainable at a fee through Library and Reports Division of the Ogice of Technical Services in the United States Department in Washington.

Application for patents on the basic principles and the improvements were made on December 3, 1945, under the Serial Number 632,504, by K. W. Miller and G. O. G. L6f. Licenses to the government have been granted.


During the last 70 years, many attempts have been made to bring about more effective utilization of the great quantity of solar energy incident on the earthls surface.

Solar heat collectors might be classified in three ways: according to (1) the type of insulation used, (2) the degree of concentrated sunshine obtained, and (3) the nature of the orientation of the collector with respect to the sun.

Insulation of the heat collection surface is accomplished in several ways. In the flat plate collector, the insulation may consist of one or more spaced glass panes placed parallel to the absorbing surface and the sides and bottom could be covered with a layer of commercial insulating material. In the case of the tubular collector, one or more concentric glass tubes may surround the heat absorbing tube and, in some cases, a vacuum is maintained between the tubes.

In the fiat plate collector, there is usually no concentration of the surfs rays, but in other types of collectors, refiectors are sometimes employed.

Any collector might be built with three types of orientation. It might be mounted permanently in one position so selected to gather the maximum amount of solar energy over the desired period; to improve its efficiency, the unit might be mounted so that its angle of inclination might be varied from day to day, so that it would always be perpendicular to the suns rays; further elaboration may be used in the mounting to permit the unit to follow the hour angle of the sun, so that it is at all times in the position to obtain the maximum amount of radiant energy from the sun.



In association with C. W. BORGMANN, C. H. PRIEN, W. B. PIETENPOL, B. H. SPURLOCK, M. M. DAVID, and J. P. POHLENZ

Departments of Chemical Engineering. Physics. and Mechanical Engineering, Engineering Experiment Station, University of Colorado.

Boulder, Colorado

In the design of a solar heat cole lector, two factors of major importance must be considered. One is the quantity of heat available at the earthts surface, and the other in the temperature level at which it is collected. Mirrors which focus the heat of sunlight and allow it to be collected at relatively high temperature levels have been devised, but these have a disadvantage in that they collect only a small portion of the total energy. On the other hand, large quantities of heat can be collected at low temperature levels by the ttgreenhouse effect? This effect utilizes the fact that glass is transparent to visible and short infra-red wavelengths which make up the predominant portion of sunlight and is opaque to long infra-red wavelengths. When sunlight enters the greenhouse, it impinges on the contents and is changed to low temperature, long wavelength heat, which is trapped inside the glass enclosure.

Since focusing devices are quite expensive to build and to operate, it seems desirable to devise a method to utilize the greenhouse effect in such a way that the temperature level of collection is

greater than previous designs have allowed.

A modification of the greenhouse effect was suggested by K. W. Miller, of the Office of Production Research and Development of the War Production Board, by which he proposed to raise the temperature level of the heat collected to several hundred degrees Fahrenheit. This plan involves the use of a large area covered by overlapping plates of glass. The area of each sheet of glass, which extends in the space on the underside, is coated with a radiation absorbing medium such as lampblack. Air is drawn slowly through the space between the plates, becomes heated, and is removed from the unit.

It is the purpose of this investigation to ascertain the workability of the scheme presented by Miller and to determine the optimum dimensions and configuration of the heat collecting unit. After it was found that the scheme of* fered an improvement over previous methods of solar heat collection, it was decided to place a unit in operation as an auxiliary heating unit in a private residence to determine its economic feasibility.

The following report describes in detail the work done and the results obtained during the course of the investigation, with the exception of the pre liminary tests on an experimental indoor heat collector.


The theory of the solar heat trap, as proposed by K. W. Miller, will be described in connection with Figure 1,

FIGURE l-Diagrummutic sketch of a solar house-heating unit. A large area: is covered by overlapping sheets of glass and enclosed within heat insulating walls. Solar heat impinges on the upper glass and the part that is transmitted to the black surface of the opaque glass is absorbed and changed into heat, As the black surface absorbs solar heat, its temperature rises and the heat is re-radiated.



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1947-48 Theatre Catalog, 6th Edition, Page 421