A "Sun valve" typically refers to a type of valve used in solar thermal systems. These valves are designed to control the flow of fluid (usually a heat transfer fluid like water or antifreeze) in solar heating applications, such as solar water heaters or solar space heating systems.

Ancestors (6)

  1. Valves
  2. Hydraulics
  3. Physical systems
  4. Concepts in physics
  5. Physics
  6. Home

View article source

Discussion (0) New discussion

There are no discussions about this article yet.

Articles by others on the same topic (1)

Sun valve by Codex 0 2026-10-18
View more
A sun valve automatically restricts a gas light's supply in daylight and allows it again as illumination falls. In Gustaf Dalén's design, a blackened rod and three polished rods respond differently to sunlight. Their relative thermal expansion operates the gas valve through a membrane; a pilot flame permits relighting. The museum dates this design to 1907.[ref]
The useful comparison is between two thermal responses. Both kinds of rod expand when warmed; a dark surface can absorb more incident radiant power, so its temperature rises more. Comparing their extensions can reject a common ambient-temperature change while responding to illumination. The mechanism converts light into heat, heat into a difference of length, and that difference into a change of gas flow. Differential thermal model of a sun valve makes those assumptions quantitative.
Figure 1.
Differential rod expansion controls daylight shutoff in a gas-lighting system
. Original functional schematic, not a scale reconstruction or copied patent drawing. The three polished rods supply a mechanical reference for the dark rod. Daylight shutoff, pilot ignition and repeated flashing have separate functions. The linkage is symbolic; no historical rod dimensions or measured displacements are specified. Details.
Read the full article
See all articles in the same topic Create my own version