Two Phase Thermo-Syphon
Water Heater Technology Development

  Click on photos for larger view.
1. Multiple TPTS Loop Lifetest Setup. All of the loops operated for at least 1,000 hours. Several were subjected to over 10,000 on-off cycles as well. These tests showed us how to build units with a very long life expectancy.
2. First TPTS Domestic Hot Water (DHW) Heater: a Solar Water Heater with a TPTS Gas-Fired Backup Heater Built for the US DOE.
3. Solar Water Heater with TPTS Gas-Fired Backup Heater, Built for GRI. This unit, with a total tank volume of 100 gallons (380 liters), was placed on field test in Hawaii, where it provided all the hot water for a family of six for nine years until the tanks started leaking. The solar fraction was about 90%; very little gas was needed.
4. Large Commercial Water Heater Built for GRI: a 200,000 Btu/hour (58.6 kW) Unit with a Tank of 120 Gallons (450 liters).
5. TPTS Test Loop With Glass Tubing for Flow Observation. This made it possible to see the startup and shutdown transients, and to estimate the fluid velocities.
6. First 40,000 Btu/hour (11.7 kW) Stand-Alone TPTS DHW Heater. This unit was developed and built on internal funding when we concluded it involved the most attractive market. This unit was tested extensively by Altas and by two outside groups.
7. First 40,000 Btu/hour (11.7 kW) TPTS Loop With a Coil Condenser. This unit was developed and built on inhouse funding when we concluded a condenser with coiled tubing was likely to be most cost effective.

updated 2000 May 30