Fusion-Type Thermal Storage Accumulator With Discharging Apparatus

The invention is concerned with thermal storage accumulators which are capable of transmitting the heat of crystallisation of fusible substances.

Storage accumulators for the storage of latent heat energy continue to gain in importance. At a high heat flux density, the thermal discharge of these accumulators encounters substantial difficulties because crusts of thermally depleted storage substance form on the surface of the heat sink portions of the accumulators. As their thickness builds up, these crusts increasingly inhibit heat transmission so that the full rate of heat withdrawal from the accumulators can only be achieved at the very first instant

The invention avoids this drawback. The invention provides, inside an accumulator container, a heat sink component, which rotates or else is equipped with a stripping device rotating around it. In this way, the storage substance, which is continuously thermally discharged by the heat transfer surfaces of the heat sink and builds up as a crust, is thrown off or stripped off these surfaces so that the favourable initial condition of a stationary accumulator endures. By this means, it becomes possible to accomplish the thermal discharge of the accumulator at high rates of heat flow. The heat sink component is advantageously arranged at the centre of the accumulator container. A fluid vortex is then formed by which the solid portions of the storage substance of higher specific weight are thrown towards the periphery of the accumulator container and become deposited there. Containers with rotational symmetry are especially favourable. The thermal charging of the accumulator takes place through a heated bottom.

The same apparatus can be used for the thermal charging of accumulators in which the density of the storage substance is smaller in the crystalline phase than in the liquid phase. In particular, this situation is true for ice. Any device which generates angular motion can be used for the thermal charging of such accumulators.

FIG. 1a is a cross-section of a thermal storage accumulator constructed according to the invention; and

FIG. 1b is a cross-section of the center portion of the accumulator of FIG. 1a.

The invention will be described with the help of Figures. FIG. 1a shows the accumulator container 1 surrounded with an insulating layer 2. A heat sink component 4 is situated at the centre of the container. A fluid heat carrier 5 flows through the pipeline 6 into the heat sink body 4 and emerges again through the pipeline 7. Stripping blades 8 are arranged around this thermal discharge heat exchanger which are rotated via a coupling 10 by a motor 9. The stripping blades 8, similarly to the blades of a windscreen wiper, are in contact with the surface of the heat sink component 4 and thus continuously strip off the continuously deposited layer of crystallized storage substance. Simultaneously, these stripping blades generate a fluid vortex, whereby the solid particles 11 in the storage substance are thrown outward and are deposited along the layer surfaces 12 so that not until almost the entire storage substance is thermally depleted does the front face of the solid storage substance portion finally stop the rotation of the stripping blades. The left-hand part of the figure shows the apparatus in the thermally charged state (the storage substance is entirely melted), whilst, on the right-hand side, a partly discharged accumulator is illustrated. With some storage substances, the crust adheres to the stripping blades 8. In this case, the invention provides that the blades slide over the surface of the heat sink component 4, which is shaped as a solid of revolution, under a pre-load, so that, by virtue of the mechanical friction, the blades are subject to a small temperature rise relative to the melt. Another method consists in conducting an electric current via a liquid heat carrier through the stripping blades 8 for the purpose of artificial heating. The heat sink component 4 is mounted on a column 14 so that the component 10, together with the stripping blades, can be withdrawn upwards. The column 14 is connected to a heat exchanger 15, which has two chambers 18 and 19 intercommunicating at the periphery. Heat carrier fluid for melting the storage substance enters through the pipeline 21. The cooled heat carrier emerges again through the pipeline 22.

FIG. 1b shows a cross-section through the stripping blades 8 and through the heat sink component 4. The stripping blades 8 are made hollow. A fluid heat carrier for heating the blades can be conducted through the duct 23.