Heat Transfer in Moving Bed Heat Exchangers for High Temperature Thermal Energy Storage.

Kurzfassung

Heat transfer inside a moving bed heat exchanger (M BHX) is closely investigat ed. For this purpose a novel simulation model has been developed whose results are comp ared to experimental data and theoretical predictions ('penetration theory'). While the penetration theory clea rly underestimates heat transfer inside the MBHX, the simulation model shows good agreem ent with the experimental da ta, especially at low flow speeds. This result indicates that areas which are supposed to have negligible contribution to heat transfer have in fact to be taken into account and that a precise modelling of the flow field is necessary. Furthermore, it is found th at the range of operating velocities of the MBHX lie in an intermediate flow regime where neither the thermal contact resistance from the wall to the first layer of particles nor the thermal penetration re sistance of the bulk can be neglected.