Abstract
The thermal advantages by utilizing discharge from different levels in solar storage tanks are investigated, both for a small SDHW system and for a solar combisystem.
The investigations showed that it is possible to increase the thermal performance of both types of systems by using two draw-off levels from the solar tanks instead of one draw-off level at a fixed position.
The best position of the second draw-off level is in the middle or just above the middle of the tank.
For the investigated small SDHW system with a realistic draw off hot water temperature of 40°C and 45°C and an auxiliary volume temperature of 50.5°C the increase of the thermal performance by the second draw-off level is about 6%.
For the investigated solar combisystem the extra thermal performance by using one extra draw-off level, either for the domestic hot water heat exchanger or for the heating system, is about 3%, while an improvement of about 5% is possible by using a second draw-off level both for the domestic hot water heat exchanger and for the heating system.
| Original language | English |
|---|---|
| Journal | Solar Energy |
| Volume | 79 |
| Issue number | 5 |
| Pages (from-to) | 431-439 |
| ISSN | 0038-092X |
| Publication status | Published - 2005 |