Heat-Transfer Characteristics of High Efficiency Solar-Thermal-Collector-Panel

1
Heat-Transfer Characteristics of High Efficiency
Solar-Thermal-Collector-Panel
Hiroyuki HAMADA and Haruki SATO Department of
System Design Engineering, Faculty of Science
and Technology, Keio University
Principle

• Characteristics of Solar-distillation-systems
  (still) using decompressed boiling
• High distillation performance.
• Vaporizing around ambient temperature.

Condenser
Secondary heat transfer fluid
Solar energy
? To understand the decompressed boiling
phenomena and the behavior of bumping water
particles in solar-thermal-collector panel is the
key for the development of the still.
Evaporator
Indoor experimental equipment
A evaporator B header C condenser D
bullet E water-supply tank F
cooling-water tank G pump H vacuum pump I
oil filtration J pressure gauge K data
logger L electric power-source
Experimental conditions
Results and Discussions

• When the temperature of cooling water is
  lower than ambient temperature, the efficiency
  for collecting thermal energy gets over unity.
• The best condition of the panel was the case
  of filling water in a quarter of inside panel
  where the heat was transferred steadily with a
  temperature difference of 2 K.
• When the panel was filled with water by
  three quarters of inside panel, the efficiency
  could be maintained to be better than 90 .
• It can be concluded that the performance of
  the panel collecting thermal energy using
  decompressed boiling is always higher than 80
• ?
• Superior than the performance of existing solar
  collectors