Second-Law Analysis of a Two-Phase Self-Pumping Solar Water Heater

Delivering Solar Energy Projects

“…For an example of optimizing four design parameters of a residential solar water heating system (solar collector area, storage tank volume, heat exchanger area, and circulating fl uid volume) to minimize life cycle cost see (Walker, 1991). Solar systems are too often sized with only a "sweet spot" in mind, such as meeting the daytime demand (kW), meeting the average daily load (kWh/day), or a size that maximizes an available incentive payment.…”

“…The Renewable Energy Optimization (REO) spreadsheet computer program has used these optimization techniques to recommend solar system sizes that minimize life cycle cost for dozens of facilities including manufacturing plants and military bases (Walker 2009a). Many search techniques have been devised to try to fi nd an optimal value among non-linear equations.…”

Cyclical reverse thermosiphon

“…Other known devices that operate autonomously and transfer heat downwards use vapour as a heat carrier and saturated vapour pressure to create lift for the condensed fluid. These devices are applied in solar installations and for the pumping of water with the help of solar collectors [3,[12][13][14]. The heat carriers used in such devices are refrigerants like Freon R-114 or pentane.…”