Zaragoza Solar Hot Water System

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Parras de la Fuente

Parras de la Fuente is a desert oasis town of about 44,000 residents located in the south of the Mexican state of Coahuila. Along with textile manufacturing, tourism is one of the main industries in Parras. Tourism has become increasingly emphasized after Parras's designation as the "primer pueblo mágico del Norte de México." Parras is warm in the summer, and cooler in the winter, but temperatures rarely fall below freezing, snow falls once every several years.

1,505 m
25o30’ N

2005 History

In 2005, Señora Rosa Guadalepe Vinelna welcomed Parras program participants to install a solar hot water system at her home, Zaragoza #1, near La fabrica mundial de la mezclilla in Parras. The system was constructed in 2005 by Alyssa Grassi (aag16 «at» - why does this email address look different?) with help from plumber Mario Cardeñas (Parras phone 422-3111 - see phone calls in Parras).

The complete solar hot water system involves heat exchange between three liquids:

  • Solar collector fluid. The fluid which is heated in the solar collector (above, fig. 2) and which the heat exchanger unit (see figs. 3 and 4), and back into the solar collector by thermosiphon
  • Intermediary heat exchange liquid.
  • Household-bound flow.

City water flows into the rooftop system through exposed metal and PVC pipes.

2006 Repairs

When the 2006 project team first visited the house, the system was not functioning. The PVC pipe which should have been carrying antifreeze from the glazed (define this at the bottom of the document) solar collector to the heat exchanger unit had ruptured and the thermal s. Despite the disabled status of the solar hot water system, the valves were still configured for water to flow from the street, to the roof, through the disconnected heat exchanger system, and into the gas water heater. The water’s flow through these pipes and systems actually heated it somewhat, presumably because of heat absorbed by the pipes and exchanger, all painted black.