SmoothPOWER is Bentrups solution for solar-powered ceramic firing. This summer, during a webinar from this innovative manufacturer of ceramic kiln controllers, I learned why this is so important.
Bentrup has more than 40 years of experience in developing controllers for the ceramic industry, artisan potters and ceramists. That’s why I wanted to hear about the latest technological innovations from the founder Reinhard Bentrup.
Connecting a ceramic kiln to solar energy is more complex than it seems. The solar energy generated must first be converted from direct current (DC) to alternating current (AC) by an inverter. The cabling must be constructed in such a way that the various components guarantee safe and efficient power transmission. This system is known as the PV (Photovoltaic) installation.
If the power from the PV system is not used directly, it can be discharged in two ways: to the electricity grid or to a home battery. But is it possible for an electric kiln to use power directly and efficiently from the PV system?
This was a question I posed to expert Reinhard Bentrup.
The challenge: firing ceramics on solar energy
PV systems range from small, rooftop-mounted systems for domestic use to large, ground-mounted utility systems. They offer a sustainable and environmentally friendly way to generate electricity. This helps ceramists reduce energy bills and reduce the ecological footprint.
Using a PV system for a device that frequently switches on and off, such as a ceramic kiln, can present some challenges. Here are some key points to consider:
- Inverter Efficiency: Inverters in PV systems are designed to provide continuous power. Frequent switching on and off can negatively affect the efficiency of the inverter. Inverters react rather slowly to load changes, as required by the power grid operator to prevent exceeding the grid voltage. This is why PV systems may only slowly add or remove power, which also helps protect the internal electronic components of the inverter. Constant switching on and off negatively influences the lifespan of these components such as capacitors and switches.
- Energy Storage: Using a home battery can help to improve efficiency. The battery can store the excess energy when the kiln is not in use and provide this energy when the kiln is turned back on. But the lifespan of a home battery is also negatively affected if it is constantly switched on and off by a device such as a ceramic kiln. This is because the battery undergoes more charge and discharge cycles, which can lead to faster wear and tear, and reduced capacity over time.
- Asset management: Advanced asset management systems can help to optimize energy production and consumption.
Ceramic kilns consume a significant amount of power in short intervals (30 seconds on and 30 seconds off) throughout the firing process. Standard inverters and home batteries are not typically designed for this pattern. Therefore, it is crucial to assess the specific requirements of your ceramic kiln and PV system and seek advice from a specialist to determine the optimal solution.
A word from the expert: Reinhard Bentrup
After attending the webinar, I realized that connecting a ceramic kiln to a PV installation is more complex than I initially thought. To explore solar-powered ceramic firing further, I reached out to Bentrup. Reinhard suggested addressing my questions in an (online) meeting.
Speaking from the recently opened Bentrup office in Cape Town, he explained how he and his team have been working over the past few years to prepare the latest generation of Bentrup controllers for solar ceramic firing. They were looking for a solution to use a PV system efficiently. Constantly switching on and off not only wears out the inverters and/or home battery, but it can also take up to 10 seconds before the system can supply power. If the kiln is on for 30 seconds, only two-thirds of the power is supplied by the sun. The first 10 seconds are then supplied by the regular power grid.
He emphasized that the traditionally used “hysteresis” procedure does not provide a solution. Hysteresis maintains a stable temperature by defining a range within which the temperature can fluctuate, causing delays in the controller’s response.
For instance, if the desired temperature is set to 1000°C with a hysteresis of 1°C, the kiln controller will turn off the heating element when the temperature reaches 1001°C and turn it back on when it drops to 999°C. This reduces the frequency of switching but results in undesirable temperature fluctuations in the kiln (not just +/-1°C, but significantly more on the coils). Moreover, this does not fundamentally solve the problem.
So what is the solution?
Bentrup SmoothPOWER: efficient solar-powered ceramic firing
Finding a balance between the energy supply of the PV system and the energy demand of the ceramic kiln is crucial. One way to achieve this is through the use of an advanced controller that can stabilize the energy input: Bentrup SmoothPOWER.
Reinhard explains that with SmoothPOWER, the heating elements are controlled in sections, resulting in three power levels. A Bentrup kiln-controller then regulate the ceramic kiln with three (instead of one) control contactors. The temperature in the ceramic kiln remains accurate thanks to the SmoothPOWER algorithm. The three phases are switched in such a way that:
- The temperature distribution is at least as good as without SmoothPOWER.
- The performance jumps are very small, which protects the inverter, battery and components.
- The solar energy is used much more efficiently when firing ceramics.
Reinhard expects that the first Bentrup technology partners will offer this solution from the autumn. The latest firmware, such as that of the TC705/707, is also SmoothPOWER ready.
However, the wiring of existing ceramic kilns needs to be adapted. Some kilns are already compatible with minimal modifications to implement Bentrup SmoothPOWER. The degree of customization depends on the specific model of the kiln and the current configuration. Bentrup prefers a HAN15X plug with at least four switching outputs.
And further innovations?
While we were on the subject of energy, I immediately asked Reinhard about the new TX series of Bentrup controllers.
The TX series is distinguished by measuring the actual power consumption of the kiln. This is in contrast to the older generation who only made an estimate. It means that ceramists now have a more accurate picture of their energy consumption. This allows them to make more informed decisions about when it’s time to replace their kiln coils.
With the help of SuperWise KilnAssist, a smart software, users can see exactly when replacing coils makes economic sense. This is especially important because new coils generate more heat than old ones, which means that heating costs increase as the coils age.
The first models of this series, the TX75 and TX95, are already on the market. And more good news is on the way. Next year, the generation X CPU is expected to be expanded with the TX708, complete with a TFT screen for an even better user experience. In addition, Bentrup is developing a separate module that makes it possible to connect older controllers, such as the TC707, to this new technology. This provides a cost-effective solution for those who don’t want to upgrade their entire system right away.
It is clear that we are heading for exciting and sunny times with these innovations. I can’t wait!
(and if I have any news, I’ll let you know in a new blog 🙂 )
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