This paper describes results of numerical experiments concerning the temperature regime and the heat transfer in an unheated and unventilated glasshouse at the nighttime. By making use of reasonable assumptions, the heat balance of the glasshouse can be expressed byiBs=(iTs-iTw){ihr+ih(1+2φ)/1+R}, for ground surfaceλ/d(iTw-oTw)=(iTs-iTw){R⋅ihr+R⋅ih(1+2φ)/1+R}, for inner surface of glassλ/d(iTw-oTw)=oFw+oh(oTw-oTa), for outer surface of glassThe temperatures (iTs, iTw, oTw) in the above heat balance equations are determined numerically by the shooting method on an electronic computer (TOSBAC 3400). The mean air temperature in the glasshouse (iTa) was determined from the following relation with reasonable accuracy:iTa=0.5(iTs+iTw).The results are summarized as follows:1. The temperature profiles inside and outside the glasshouse at the nighttime are considerably affected by both the soil heat flux (iBs) and the effective long-wave radiation flux (Fo). The temperature profiles can be classified into the following two groups:iTs>iTw>oTw>oTa, for iBs>FoiTs>iTw>oTw<oTa. for iBs<FoIn the first group, heat is transferred through both the inner air layer and glasswall from the ground into the outer air layer, indicating that the sensible heat flux at the outer surface of glasswall is upward. In the second group, the heat supplied to the glasswall from both the air layers is dissipated as effective long-wave radiation into the air.It is concluded from the results that the increased area ratio (R=As/Aw) and iBs lead to the increased temperature excess (oTw-oTa). The temperature excess was found to increase with ih, oh and Fo. The temperature excesses are larger for a dry house than for wet one, mainly because of the higher resistance to heat transfer in the dry house.2. The following relationships are obtained between sensible heat transfer coefficients (ih, oh) and meteorological elements and structural factors of the house:ih=1+R/1+2φ{iBs/(iTs-iTw)-ihr}, oh=R⋅iBs/(oTw-oTa){1-fFo/R⋅iBs}-f⋅ohr.The above relations can be used for determining the coefficients by which the temperature regime and the heat transfer in the house are expressed.3. As can be seen in Figs. 6 and 7, the temperature excess (iTa-oTa) is affected not only by iBsand Fo but also by R, oh and ih. The denpendence of temperature excess on the sensible heat transfer coefficient (oh) was essentially different according as iBs is larger or smaller than
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