A flat-plate solar collector with spiral tubing

Conference · Mon Dec 01 04:00:00 EST 1980 · Alternative Energy Sources; (United States)

OSTI ID:6927162

Akugn, M; Parlar, M N

In this work, a flat-plate collector having a circular absorbing plate with a spiral tube for fluid passage is investigated. An analytical expression is obtained for the collector outlet temperature. The whole system is considered as lumped at a mean temperature and daily variation of the mean fluid temperature is determined numerically. Thermosyphon flow is analysed using a system temperature distribution diagram and a polynomial expression is obtained for the thermosyphonic flow rate, which is then solved on a digital computer using the knowledge of mean fluid temperature. Experiments are performed with a spiral tube collector model and fairly good correlations are obtained for the mean temperature. Flow rate could not be measured in the experiments. Some problems related to the development of thermosyphon flow were observed in the experiments. The system had long transients before the normal flow could develop. However, this problem was partly due to the steel plate being massive and therefore inefficient. Computed thermosyphonic flow rates were around 3 g/s for a clear summer day, experimental daily efficiencies being 35-40 percent. Spiral-tube collector has several advantages over the conventional sheetand-tube type with riser-header arrangement. Temperature increase form collector inlet to outlet is higher in a spiral-tube collector. This is an advantage where high temperature is required. Secondly, average tube-to-fluid heat transfer coefficient is greater owing to the curvedness of the tube.

• Research Organization: Electrical Engineering Department, Middle East Technical University, Ankara
• OSTI ID: 6927162
• Report Number(s): CONF-801210-
• Conference Information: Journal Name: Alternative Energy Sources; (United States) Journal Volume: 1
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
141000* -- Solar Collectors & Concentrators
CONFIGURATION
CONVECTION
ENERGY TRANSFER
EQUIPMENT
FLAT PLATE COLLECTORS
FLUID FLOW
FLUIDS
HEAT TRANSFER
HEAT TRANSFER FLUIDS
PERFORMANCE TESTING
SOLAR COLLECTORS
SOLAR EQUIPMENT
SPIRAL CONFIGURATION
TEMPERATURE DEPENDENCE
TESTING
THERMOSYPHON EFFECT
TUBES