Fabrication and Performance Study of a New Design of Passive Thermosyphon Type Solar Water Heater

Abstract

The work presents an example of a passive solar heating system, which utilizes direct solar energy to heat the water for domestic use. A passive thermosyphon heating system was designed, fabricated, and tested for its thermal performance in the semi-arid and four-season climate of the Faisalabad district of Pakistan. The heating system design was based on two-stage storage and natural thermosyphon circulation of water. An enhancement of the thermal performance of the thermosyphon systems by using a semicircular steel pot collector (covered with water carrying copper coil), two-step water storage, and side mirror reflectors was investigated. The experiments were conducted from April to July, 2014 when the ambient temperature was reported approximately between 30 to 45°C. For the cited time duration, the cold-water temperature remained in the range of 18 to 25°C. The maximum water temperature, during the intermittent flow mode operation of the system, remained between 48 and 88°C. In continuous flow mode operation, the hot water temperature remained between 46 and 78°C. Since water temperature in the range of 45 to 50°C is considered suitable for domestic use, the presented design is acceptable for domestic use.