| Title | Thermodynamic and Thermoeconomic Analysis of Combined Geothermal Space Heating and Thermal Storage Using Phase Change Materials |
|---|---|
| Authors | Vijay CHAUHAN, Árni RAGNARSSON |
| Year | 2015 |
| Conference | World Geothermal Congress |
| Keywords | space heating, geothermal, energy storage, heat storage, phase change material, exergy, thermoeconomics |
| Abstract | The present work discusses utilization of geothermal energy for space heating in combination with phase change energy storage system. Thermodynamics and thermoeconomics of the combined heating and thermal storing system were studied to show the scope of energy storage and cost savings. The analysis was done taking second law efficiency into consideration since the second law represents true flow of energy. The space heating is based on geothermal water that is used in a plate type heat exchanger to give heat to the secondary fluid which is passed through the radiators for room heating. Heat supply to the storage system was provided from the geothermal water at the exit of the heat exchanger. A computational model of the combined space heating and thermal storage system was developed and used to perform thermodynamic studies of the heat storage process and heating system efficiency at different times and ambient temperatures. The basis for these studies is daily variations in heating demand that is higher during the night than during the day. The results show the scope of utilization of phase change material for low ambient temperature conditions. Under proper conditions sufficient amount of exergy is stored during charging period at low ambient temperature to fulfill the day time heat load requirement. Under these conditions the cost flow rate of exergy storage is found to be lower than the radiator heating cost flow rate. Thus, the usage of exergy storage at low ambient temperature for heating at higher ambient temperature makes significant contribution in cost saving. The paper makes references too many studies on exergy analysis and thermal energy storage systems using phase change materials. |