The Congress Programme
Energetic optimization possibilities of industrial drying processes 
This presentation shows the possibilities of a heat pump dryer test bench, aided by a simulation model. Potential energy savings up to 25% are possible, just by optimizing a basic drying process but without integration of a heat pump. By adding a well adapted heat pump the energy input can drop with 85% related to the original one or with 63,6% if the electrical part of it is recalculated to the primary energy input supposing a heat to power conversion efficiency of 40%. Once the model is further optimized and validated by tests, it will allow to design energy efficient drying systems, starting from an existing installation or from scratch. Accompanying demonstrations should convince the project owners. These possible concepts also include the use of a gas engine driven heat pump which could be preferred in regions with a higher electricity to gas price ratio, but is yet to be included in the model. Simulations reveal R245fa to be an all-round well performing fluid for heat pump dryers, especially for the higher temperature range. Depending on heat sink and – source conditions, significant energetic benefits can be realized with a suction line heat exchanger and a sub cooler. Utilizing an internal heat exchanger in the air cycle, also to preheat fresh air with outgoing air in case of a (partially) open drying system, the COP drops because of an increased remaining temperature lift but the required heat pump capacity decreases. Furthermore, the amount of heat extracted can be controlled not only by the heat pump pressure ratio, but can be complemented by an evaporator bypass. Besides demonstration of optimization possibilities on the drying cycle, the test rig will offer an excellent environment for research on advanced heat pump systems including novel control systems.
--- Date: 23.10.2019 Time: 15:45 - 16:10 Location: Hall Brüssel, NCC Mitte