Thermosyphon and pumped solar water heaters : testing methods and experimental evaluation of long term performance | |
| Author | Macatol, Hilarie Teresa Colinares |
| Call Number | AIT Thesis no.ET-86-3 |
| Subject(s) | Water heaters Solar energy research |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Environment, Resources and Development |
| Publisher | Asian Institute of Technology |
| Abstract | The theoretical and experimental performance of two solar water h eaters has been evaluated. One system with a horizontal storage tank was operated under thermosyphon flow conditions only. The other system, with a vertical storage tank was alternately operated under three modes: (a) thermosyphon flow, (b ) pumped system with mass flow of 36.5 kg/m2 h, and (c) pumped system with mass flow rate of 55 kg/m2 h. Tests were conducted under a wide range of weather conditions over three months. These show that the experimentally determined daily system efficiency with respect to solar insolation with no heat withdrawal during insolation period, is more or less unaffected by flow mode. This suggests that, for domestic applications at least, the thermosyphon solar water heater is to be preferred over the pumped system since no external pump is required, nor is there a need for a differential temperature controller . It was also noted that the daily system efficiency of the solar water heater with horizontal storage tank was lower than that of the vertical tank system by 13 % (relative units ). Thus assuring proper thermal stratification in the storage tank may lead to a non- negligible increase in overall solar system performance. Saunier proposed a model for the thermosyphon flow rate of passive solar water heater which involves experimental determination of two system performance parameters. The validity of this model was tested on both vertical and horizontal storage tank systems over both cloudy and clear day. It was found that the model was accurate in general to within 1 to 2°C for predicting the evolution of storage temperatures and collector inlet and outlet temperatures of both types of systems operating under different operating weather conditions. The theoretical model presented could be used for design purposes to evaluate the long term thermal performance of a solar water heater operating under thermosyphon-flow conditions . |
| Year | 1986 |
| Type | Thesis |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Other Field of Studies (No Department) |
| Academic Program/FoS | Energy Technology (ET) |
| Chairperson(s) | Reddy, T. A. |
| Examination Committee(s) | Exell, Robert H.B. ;Prida Wibulswas |
| Scholarship Donor(s) | Shell International |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 1986 |