Abstract

MARROQUIN DE JESUS, Á.; OLIVARES-RAMIREZ, J.M.; RAMOS-LOPEZ, G.A.  and  PLESS, R.C.. A Flat Solar Collector Built from Galvanized Steel Plate, Working by Thermosyphonic Flow, Optimized for Mexican Conditions. Ing. invest. y tecnol. [online]. 2009, vol.10, n.3, pp.269-283. ISSN 2594-0732.

Design, construction, and testing of the thermal performance of a flat solar collector for domestic water heating are described. The absorbing plate is built from readily available materials: two sheets of galvanized steel, one of the channelled type, the other one flat, which are joined by electric welding. The absorber is connected to a 198-L thermotank, insulated with polyurethane foam. In terms of receiving surface, the prototype tested here has an area of 1.35 m², about 20% smaller than comparable copper-tube-based collectors offered in the market. Temperature measurements conducted over a 30-day period gave values which were a few degrees lower than the theoretically calculated water temperatures. Momentary thermal efficiency values between 35% and 77% were observed. The water temperature achieved in the tank at the end of the day aver ages 65°C in winter weather conditions in the central Mexican highland. This design of solar water heater is well suited to Mexican conditions, as it makes use of the high local intensity of the solar radiation, and as the channel shape of the ducts minimizes bursting during the rare occurrences of freezing temperatures in the region; it also has the advantage of being manufacturable at low cost from simple materials.

Keywords : Flat solar collectors; thermosyphonic flow; channelled plate; simulation; instantaneous thermal efficiencies.