Abstract: An apparatus, thermal storage system and method for heat exchange using a tube-type heat exchanger. A rod (24) or rods (24, 24') are propelled to move over the inner surface (7) of the tube (1). The moving rod (24) is in contact with a first process liquid which is adjacent the inner surface (7) as a falling film or by flooding the interior of the tube (1). The flooded mode is particularly useful where the tube (24) is non-vertical or the heat exchanger is used to make an ice slurry for HVAC systems serving high-rise buildings. Multiple such rod (24) and tube (1) assemblies are operated simultaneously using a drive plate (22) powered to execute an orbital motion in a plane generally orthogonal to the rods (24, 24'). In one form the plate (22) is coupled via a crank (40) to equiangularly spaced rods (24, 24') in each tube (1).

Abstract: A scraped surface heat exchanger comprises a pair of concentric heat exchange tubes. A heat exchange medium passes through the annular chamber between the tubes and a fluid, in particular one whose viscosity increases as it passes through the heat exchanger and whose temperature is to be modified by heat exchange with the heat exchange medium in the annular chamber, passes through the inner of the tubes. A helical scraper blade arrangement extends along the length of the shaft within the inner chamber. The scraper blade arrangement comprises one or more thin plastics or metal blades set within a helical slot which is angled against the direction of flow of the fluid medium and makes with the internal surface of the inner tube a contact sufficient to allow the blade arrangement to rotate within the inner tube when conveying through it the fluid whose temperature is to be modified.