Passive solar massive wall systems with fins attached on the heated wall and without glazing

Natural convection. radiation and conduction heat transfer in passive solar massive wall systems with fins attached to the heated surface and without glazing is experimentally studied. The system was 0.78 m high, 0.40 m wide, and 0.10 m thick concrete wall with 0.025 m long. 0.004 m thick horizontal fins made as an integral part of it and placed at 0.01 m intervals. A heat source was used to impose a constant heat flux which could be varied from about 200 to 800 W/m(2). Temperatures at various points and heat flux by convection at the back were measured. Using periodicity hypothesis and various assumptions, the wall with fins was also analyzed theoretically. The results indicate that for the case considered, about 35 percent of the heat flux imposed on the finned surface goes through the system and is dissipated at the back.