Use of a new type of heat transformer in process industry

There are many instances in the process industry where low-temperature or waste heat occurs. Despite considerable attempts at optimization, this heat flow is often given off unused into the environment. In this report, a special new type of heat transformer (TRAXX) is described which makes it possible to transform economically low-temperature waste heat (60-100 degrees C) into useful heat of a higher temperature (90-160 degrees C). This high quality heat can be used in the original process or in other processes. Scarcely any valuable mechanical or electrical energy is needed as drive power; rather part of the energy from the residual heat flow serves to drive the heat transformer. The heat transformer TRAXX operates in accordance with the absorption principle, in the reverse way that an absorption refrigeration plant functions. The key components are a desorber, an evaporator, a condenser and an absorber from which useful heat is extracted. The results of the development of a special heat transformer, TRAXX, are presented here. First of all a pilot plant with a useful heat flow of 100 kW was built and then tested. From this were derived the basic data for a new cycle which is in the position to transform the heat by greater temperature differences (more than 60 degrees C). This is achieved by installing an additional absorber. A plant with 4 MW useful performance was designed following this principle. The primary objective is to gather experience with the plant in operation as well as energy recovery. (C) 1998 Elsevier Science Ltd. All rights reserved.