Forschungsgruppe-NET - Hochschule Offenburg

Solar Heat

Measurement Data Evaluation

The measurements described below are taken every 1-2 seconds by a data collecting device (type: HWH DL32). Normally, they are saved as 5-minute average values. Shorter saving intervals (< 5 mins) are possible; they are usually carried out to monitor the dynamic behavior of the system, e.g. during trial runs. For most of the measurement values, the system also records the minima and maxima over a 30-minute interval. These provide further information of the system’s operation. Regular controls of the minima and maxima can detect measurement errors, which might be caused by a faulty sensor. Incorrect average values can thus be singled out easily.

The data logger records power (kW), volume flow (m³/h), temperature (C°), pressure (bar), energy (kWh) as well as the total operating hours every 1 to 2 seconds. All the values are saved every 5 minutes.

By analyzing the measurement data with a fairly high temporal resolution (average values over 5 minute intervals), it is possible to assess the system’s performance and identify problems. On the basis of the malfunctions identified through these analyses, the solar thermal system was modified substantially after start-up.

Intensive Measurement

In the course of the program Solarthermie, an intensive measurement phase of two years is a requirement. Thereby, system values are intensively monitored and evaluated. The objective of this detailed monitoring is twofold: on the one hand, it serves to optimize the plant operation and increase the system’s efficiency, on the other, it helps to test the manufacturer’s specifications in relation to the energy yield.

The pdf documents below show the most important measurement results of the first three years of the solar thermal cooling system at Esslingen. These include the useable energy, the solar fraction, the system’s overall efficiency and the collector efficiency.

DATAPOOL provides access to our data server

Via DATAPOOL you can access selected data of this solar thermal system. You can choose from various illustrations like line charts, carpet plots, or scatter plots.

The solar thermal system at Festo AG & Co KG, Esslingen can be found on the Datapool pages under Solar Thermal Systems as far as measurement data are available for this system. 

The individual measurement points of the data pool can be found in the diagram above or here

For a list of the measurement points, click here