CHAPTER XIII. 



GREENHOUSE AND ^ATINDOW-GARDEN 

 AA^^ORK AND ESTIMATES. 



I. The Heating of Greenhouses. 

 (By Pi-ofessor K. C. Carpenter.) 



I . Methods of proportioning Radiating Surface for heating 

 of Greenhouses. 



Radiating surface, whether from steam or hot-water pipes, is 

 estimated in square feet of exterior surface. All projections, 

 ornaments, etc., on the exterior of pipes or radiators are 

 counted as efiicient surface. Formerly, cast-iron pipe of about 

 4 inches in diameter was used almost altogether for greenhouse 

 work ; it is still used to some extent for hot-water heating, but 

 the great majority of houses are now piped with wrought iron, 

 which is made of standard size and thickness, and is a regular 

 article of trade. 



The heating surface in a boiler or hot water heater is that 

 portion of the boiler, or heater, which is exposed to the direct 

 heat of the fire or of the heated gases. 



Grate surface is the number of square feet of grate in the 

 boiler or heater. 



In estimating the heat required for greenhouses, the area 

 expressed in square feet of glass in the roof and walls is taken 

 as the basis from which computations are made. Certain rules 

 of practice have been adopted and appear to give fairly good 

 results in proportioning radiating surface, grate surface, and 

 heating surface. The ratio of heating surface to grate surface 

 will depend upon the kind of coal to be burned and the economy 

 desired. The more heating surface provided per unit of grate 



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