Operational Experience of a Centrifugal Particle Receiver Prototype

The centrifugal particle receiver “CentRec” is a solar tower receiver development by DLR based on a direct absorption receiver concept especially suitable for high temperature process heat and electricity generation applications. Ceramic particles are used as heat transfer and storage medium for temperatures up to 1000°C. A centrifugal particle receiver system including a CentRec receiver prototype has been tested up to 965°C average receiver outlet temperature in the research platform of DLR’s test facility Juelich Solar Tower, Germany. This paper describes the first test results with a focus on first operational experiences

Operational experiences with the heliostat field at the Juelich solar towers

The heliostat field at the Juelich solar towers meanwhile has a history of 15 years of operation experience. This paper gives a short overview over the problems and improvements since the first erection of the field. Reflectors had to be replaced after just 5 years of operation and have been refitted with a high quality four facet reflector system with individual canting. Results of deflectometric measurements will be demonstrated. The poor tracking performance of the initial heliostat design led to a retrofit of the tracking system in the years 2019 to 2023. With the current system precise tracking could be achieved since mid-2021. This paper will show different technological approaches to reach the desired quality improvements. Tracking results from the first days of operation to the current day will be presented. The whole field is operated by the heliostat field control system HeliOS. The control system has some specific functionalities which are uncommon to standard single tower systems but are a requirement for the research focused field in Juelich and for the simultaneous operation of multiple receivers in two adjacent towers by multiple operators. We will demonstrate some features of the system in this paper

First On-Sun Tests of a Centrifugal Particle Receiver System

One direct absorption receiver concept currently investigated at the DLR is the Centrifugal Particle Receiver (CentRec®). Successful tests and promising results of this receiver design have been achieved in a Proof-of-Concept scale with 7.5 kW thermal power and 900°C particle temperature in 2014. Based on these results the prototype has been scaled up to 2.5 MW thermal power for a future pilot plant. Lab tests have been carried out with infrared heaters. In a next step the prototype has been prepared to be tested on-sun in a test setup in the Juelich Solar Tower, Germany. The tests aim to demonstrate high temperature operation and to evaluate the performance of the system. The test setup consists of a centrifugal receiver integrated into the tower and a closed loop particle transport system. The transport system includes an air cooling system to cool down the particles at the receiver outlet, cold particle storage, belt bucket elevator, hopper and particle metering system. While the 2.5 MWth receiver prototype has been developed in a former project, the further infrastructure for the on-sun tests needed to be designed, manufactured and installed. The system is equipped with measurement instrumentation, data acquisition system and control software. Manufacturing of all main components has been completed. Installation of the test setup started in November 2016 and finished in June 2017. Cold and hot commissioning have been carried out from July 2017 until September 2017. On-sun tests started in September 2017. Receiver tests up to 775°C/1,430°F receiver outlet temperature and more than 900°C/1,650°F particle temperature in the receiver have already been achieved. Tests up to 900°C particle outlet temperature are planned at different load levels and will be conducted until summer 2018. This paper describes the test setup for a centrifugal particle receiver system, presenting design, installation and commissioning of the system. It presents test results of first onsun tests and gives an outlook on further steps regarding solar tests planned for 2018