Energy Convers. Mgmt Vol. 32, No. 6, pp. 555--563, 1991 0196-8904191 $3.00+ 0.00 Printed in Great Britain. All rights reserved Copyright © 1991 Pergamon Press pie THERMAL EVALUATION OF A "WINTER HOUSE" R. K. JHA, i G. N. TIWARI, l H. P, GARGI? and Z. H. ZAIDP ~Centre of Energy Studies, Indian Institute of Technology, Hauz Khas, New Delhi-110 016 and 2Department of Physics, Jamia Millia Islamia, Jamia Nagar, New Delhi-ll0 025, India (Received 19 May 1990; received for publication 21 January 1991) Abstract--In this paper, the transient thermal model of a "Winter House" has been presented for a cold climatic region of Srinagar in India. In order to reduce the fluctuations in living room temperature, the effect of an isothermal mass has been incorporated in the thermal model. An analytical expression for room temperature has been derived to evaluate the performance of the "Winter House" by incorporating the effect of movable insulation during the night. Numerical calculations were done in terms of system as well as climatical parameters. Some isothermal mass, like water, has been considered to stabilize the room temperature throughout the day and right. For further heating, the effect of the roof as an air collector has also been taken into account. Solar heating of "Winter House" Isothermal mass room temperature Solar air heater Prediction model of NOMENCLATURE A~fr= Total area of south wall (m 2) AF = Area of floor (m 2) Aw = Area of walls (m 2) As = Area of south wall (m 2) A R = Area of roof (m 2) Ca = Specific heat of air (J/kg °C) C~ = Specific heat of isothermal mass (J/kg °C) hE,r~,w,s,R = Heat transfer coefficient between wall to ambient (W/m 2 °C) hrRE.N,W, s = Radiative heat transfer coeffÉcient between walls and room (W/m 2 °C) hcRE.N+W,S = Convective heat transfer coefficient between walls and room (W/m 2 °C) hCRRF= Convective heat transfer coefficient between roof and room (W/m 2 °C) hcRF = Convective heat transfer coefficient between floor and room (W/m 2 °C) hrRF = Radiative heat transfer coefficient between floor and room (W/m 2 °C) I(t) = Solar insolation C,~//m 2) rna = Mass flow rate of air below roof (kg/s) M, = Mass of room air and isothermal mass inside room (kg) 774--Ambient air temperature (°C) TE,W,~. s -- Temperature of four walls (°C) T F -~ Temperature of floor (°C) TRF = Temperature of roof (°C) T R = Temperature of room (°C) T~ ---Ground temperature (°C) URE,N,W.S = Overall heat transfer coefficient of four walls (W/m 2 °C) URR F = Overall heat transfer coefficient of roof (W/m 2 °C) URF = Overall heat transfer coefficient of floor (W/m 2 °C) Greek letters = Absorptivity of south glass wall z = Transmittivity of south class wall p = Density of air (kg/m 3) Subscripts E = East F = Floor N = North S - South RF = Roof W = West tTo whom all correspondence should be addressed. 555