Thermal constriction resistance at the interface of double tubes

Journal Article · Sat Feb 01 04:00:00 EST 1986 · J. Sol. Energy Eng.; (United States)

DOI:https://doi.org/10.1115/1.3268059· OSTI ID:5751468

Wang, J C.Y.; Nowak, E S

In recent years the double-tube heat exchanger with longitudinally fluted grooves in the outer tube, has found increased usage in the solar energy industry. The hot water heater in the liquid-based solar water heating system is one example. An antifreeze solution is commonly used as the heat transfer fluid, circulating between the solar collector and the hot water heater. It is essential, according to governmental regulations and safety codes, that the antifreeze solution does not come into contact with the water in the hot water heater. The purpose of the double-tube heat exchanger with longitudinal grooves is to detect the leakage of fluid flowing through a fissure or a fracture from either tube into one of the grooves. Immediate action can then be taken to prevent the mixture of the antifreeze solution with water. It is believed that the thermal contact resistance in a double tube is more important than the thermal constriction resistance, and the problem will be more complicated and difficult if both resistances are investigated simultaneously. As an initial step in gaining a basic understanding of heat transfer through a double tube as described above, other studies focused on thermal constriction resistance alone. This paper extends and integrates the earlier works. The thermal contact resistance is omitted and a simplified approach has been taken in this theoretical study. Additional data are presented and discussed.

• Research Organization: Centre for Building Studies, Concordia University, Montreal, Quebec, H3G 1M8
• OSTI ID: 5751468
• Journal Information: J. Sol. Energy Eng.; (United States), Journal Name: J. Sol. Energy Eng.; (United States) Vol. 108:1; ISSN JSEED
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
140907* -- Solar Thermal Utilization-- Water Heating
ANTIFREEZE
APPLIANCES
EQUIPMENT
FAILURES
FLUID FLOW
FLUIDS
FRACTURES
HEAT EXCHANGERS
HEAT TRANSFER FLUIDS
HEATERS
HYDROGEN COMPOUNDS
INTERFACES
LEAK DETECTORS
MIXING
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
REGULATIONS
SAFETY
SOLAR COLLECTORS
SOLAR EQUIPMENT
SOLAR WATER HEATERS
THERMAL CONDUCTIVITY
THERMODYNAMIC PROPERTIES
WATER
WATER HEATERS