Mar., 1938] Electric Brooding of Chicks, II. Heat Requirements 13 



grees, while on the second night it averaged +14 degrees, a difiference 

 of 22 degrees. The air in the house the first night averaged +10 de- 

 grees, and the second night +20 degrees, a difference of 10 degrees. 



A study of the diagram shows that the double wood floor in House 

 13 maintained a difference of 24-25 degrees ; the double wood and I/2'' 

 insulation in House 14 maintained 31 degrees ; the double wood and 1" 

 insulation in House 15 maintained 38-40 degrees ; and the double wood 

 with 1^" insulation in House 16 only 33-38 degrees. 



Under the conditions of this experiment the double wood floor with 

 1" of insulation or its equivalent was the point of declining value, and 

 we are led to believe that this amount will keep down heat leakage 

 through the floor under the brooder as well as more insulation. More- 

 over, there is nothing to indicate that a double wood floor with a disc 

 of 1" insulation board or its equivalent, properly waterproofed and 

 slightly larger than the brooder, placed on the floor under the brooder, 

 will not be just as good as, or better than, built-in insulation, and is 

 certainly less expensive. This would have an uninsulated area out- 

 side of the brooder to collect and transmit to the under-house section 

 as much sun's heat as possible, with its attendant storage hold-over 

 effect. 



Floor Insulation Temperatures (1934-1935) 



Temperature readings in the floors as taken by the thermocouples 

 placed in the various floor layers are shown graphically in detail in 

 Figure 6 for a night when the prevailing outside temperature dropped 

 to near 15 degrees below zero. 



Due to the different makes of brooders with their variations in 

 heat production values and operating characteristics, it cannot be said 

 that the exposure to heat on the floor surface was the same in each case. 



House 13 shows a well defined relation between the outside tem- 

 perature and that of the floor at all three locations. The outside tem- 

 perature dropped 24 degrees in eight hours. The surface of the floor 

 dropped 15 degrees in the same period — 2 degrees greater than the 

 under-house or internal floor drop. 



This 2-degree difference, while not great, is deemed of considerable 

 significance as it indicates a more rapid loss of heat than can be ac- 

 counted for in any other readings through the floor section. This sug- 

 gests the conclusion that floor drafts and brooder house air are sources 

 of greater heat loss than through-the-floor-radiation, provided the floor 

 is at least a double layer of wood with one layer of paper between. 



Curve B in House 14 shows that the temperature just under the 

 surface wood flooring is, on an average, about 12-14 degrees improve- 

 ment in temperature over the corresponding point in the floor of No. 13. 

 (The surface floor temperature was lost through failure of a buried 

 thermocouple. ) 



In the case of House 15, neglecting the other points of measure- 

 ment, Curve B (just under the surface flooring) shows the best regula- 

 tion of any group with a variation of only 8 or 9 degrees, although the 

 temperature level is about 5 degrees less than No. 14. The general 

 characteristics of all curves for this house show improved regulation 



