| Author | Ramos, Chrystalyn Ivie Sunpongco |
| Call Number | AIT Thesis no.ET-05-15 |
| Subject(s) | Heat storage--Simulation methods
|
| 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 | A comparative study of the performance of a rock bed heat storage unit was completed wherein the theoretical performance of the bed was investigated by simulating the behavior of the heat storage unit through the TRNSYS simulation software. The performance parameters of the rock bed heat storage unit evaluated were in terms of the temperature distribution within the rock bed, the rates of heat stored and recovered during charging and discharging, respectively, as well as the charge and discharge efficiencies. Based on these, experimental investigations ascertained that the simulation results were able to predict the measured results within the accuracy of the data. The rock bed operating parameters both in the simulation and experiments include medium charging temperatures of 50, 60 and 70 °C and high charging temperature of 105 °C. Flow rates of 195 m3/hr and 120 m3 /hr were used to store hot air through the bed during charging for the medium and high temperature charging, respectively. On the other hand, discharge flows are 120 m3/hr and 100 m3/hr. Energy analyses revealed that temperatures of 70 and 105 °C exhibited the most optimum performance. The rates of heat stored were found to be in the range of 70.57 MJ/m3 (48.78 MJ) to 76.44 MJ/m3 (52.84 MJ) of rock bed heat storage unit at 70 °C with an efficiency of around 61 % and maximum losses to a range of 0.61 ± 1.61 MJ/m3 hr (0.42 ± 1.11 MJ/hr). The total rate of heat recovered may lie between 62.70 and 68.14 MJ/m3 of rock bed heat storage unit after 15 hours of discharging. Heat loss have a maximum of 0.56 ± 1.69 MJ/m3 hr (0.39 ± 1.17 MJ/hr) during the first hour of discharging while discharge efficiency is calculated to be around 61 % as well. The rates of heat stored at 105 °C had an average deviation of 1.9C'c where actual rates may vary between 93 MJ/m3 to 122.7 MJ/m3 (64.31 MJ and 84.81 NIJ) of rock bed heat storage unit with charge efficiency between 75.4% and 70.1% having relative difference of 7%. Heat losses for this operation may vary between 1.26 ± 5.31 MJ/m3 hr (0.87 ± 3.67 MJ/hr). The total rate of heat recovered is expected to lay between 31.13 MJ and 32.17 MJ (45.04 to 46.54 MJ/m3 of rock bed heat storage). Heat losses are expected to be almost ± 0.38 MJ/m3 hr from the mean values of the hourly heat losses in all the 8 hours of discharging. The discharge efficiency was found to deviate less than 10% having a mean discharge efficiency of 65.5% |
| Year | 2005 |
| Type | Thesis |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Department of Energy and Climate Change (Former title: Department of Energy, Environment, and Climate Change (DEECC)) |
| Academic Program/FoS | Energy Technology (ET) |
| Chairperson(s) | Kumar, S.; |
| Examination Committee(s) | Surapong Chirarattananon;Athapol Noomhorm; |
| Scholarship Donor(s) | Government of France and
Asian Institute of Technology Fellowship; |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 2005 |