| 165 / | HD | HEAT EXCHANGE |
| DIG 9 | DD | HAVING A SOLID HEAT STORAGE MASS FOR ABSORBING HEAT FROM ONE FLUID AND RELEASING IT TO ANOTHER (I.E. REGENERATOR) {5} |
| DIG 13 | DD | .~ Movable heat storage mass with enclosure {3} |
| DIG 16 | DD | .~.~ Rotary storage mass {6} |
| DIG 17 | | .~.~.~ With thermal expansion compensating means |