Cool efficiency

When it comes to industrial cooling units, there is no doubt that Rittal boasts one of the strongest pedigrees around, first entering the market in the mid 1980s. The company introduced a further generation in 2002, the Top Therm, which still exists today albeit with a few revisions that have been intro ducked over the years. For example, the heat exchangers now feature a nano-coating which offers protection from dust and means units can more or less work continuously in arduous environments.

More recent revisions started to focus on energy efficiency, influenced by the knowledge Rittal had gained from its involvement in the IT market. “We saw energy efficiency gain in importance in the IT sector a long time before it did in the industrial market,” says Dr Thomas Steffen, Rittal’s managing director, research and development. “Energy consumption in IT cooling a very big issue; you need much more electricity for cooling than for running servers.

“So, based on our experience in the IT sector, in 2013 we started to think about a complete new generation. We took out our three best designers for a period of six months and, without the distraction of day-to-day business, asked them think about what we could do to bring this about. The result of this process was the Blue e+ generation, which was introduced to the market at the Hannover fair in 2015.”

Hybrid technology

With the Blue e+, Rittal is able to offer energy savings of up to 75%. In fact, in many applications, the reported figures are even higher. This has been achieved through the use of hybrid technology incorporating passive climate control in the form of a heat pipe cooling circuit, which works in parallel with a conventional cooling circuit.

Dr Steffen explains the thinking behind the design: “In Europe and the US, in many industrial areas we have an ambient temperature of between 20 and 25 degrees. In this ambient temperature, only the heat pipe needs to run to provide cool air. That means electricity is only needed for the fans, not for the compressor – and the compressor is the highest consumer of energy. So in these situations the Blue e+ units can run with an energy efficiency ratio of up to between 14 and 15.

“Of course, the warmer the ambient temperature, the less cooling is supported through the heat pipe. Nevertheless, at 30 degrees, we can still achieve an energy efficiency ratio of five.”

As Dr Steffen points out, it is all very well achieving these kind of results in the laboratory, but the real test comes when the equipment is out in the field in working applications, and this is why Rittal worked extensively with partner-customers on a wide-ranging programme of field testing. Following extensive ‘stress’ testing at Rittal’s production facility in Germany where units were put through their paces in an ambient temperature of 50 degrees over four weeks, units were put into everyday use at the company’s plant, and then at customer sites.

“We get great results in the laboratory, but we get even better results from the customer sites!” says Dr Steffen. “It’s curious because hybrid technology is nothing new; the principle has been well known for many years but finally we gave our best designers the chance to really think. It is a good example of what engineers are able to generate even today if they have the time to do it.”

Compared with the previous generation of Rittal coolers – which as Dr Steffen points out, were among the most energy efficient available anyway – Blue e+ units monitored at customer test sites resulted in energy savings ranging variously from 17.1% at Volvo to 91.2% at Daimler, with average being around the 75% mark.

Multi-voltage support

And it’s not just energy efficiency that users will benefit from; Blue e+ coolers feature multi-voltage support and inverter technology so that, unlike the previous generation and competitor products which have different units for different voltage needs, with this generation each unit covers all voltage needs worldwide.

Another advantage of the inverter technology is that, with just 5 degrees of hysteresis, the units run at very constant temperatures enhancing the lifetime of the equipment and making it, says Dr Steffen, particularly attractive for end users in the automotive sector with paint shop installations.

A further feature of the new generation, and one that fits particularly well with Industry 4.0, is the built-in communications capability. “Of course we provide internet communications to our customers’ control system, but we have also installed another kind of communication, where customers can download all the data from the cooling unit – basic data and data for the actual application for, say, the last month –  this can be via email and we are also working on a portal,” says Dr Steffen.

This means that in case of a failure, service personnel can arrive at site with the correct spare parts and, in addition, causal factors can be ascertained. It also aids preventative maintenance.

Taking this process a step further, Cloud-based applications can be provided through Trumpf spin-off, Axoom, enabling Rittal to analyse large amounts of data and gain more detailed knowledge of the application, again enhancing predictive maintenance strategies.

As you might expect, all these features do come at a cost, however, this is more than outweighed by the benefits, as Dr Steffen explains: “Overall, we have had to pay for such positive results with much more electronic competence; this makes the unit more expensive, but on the other hand we have been able to reduce the cost of the heat exchanger. We are therefore able to provide these units at a price less than 10% higher than the old ones and offer a return on investment of just a few months.

“We have provided internet calculations for customers, so that they can easily see for their region and ambient temperatures what it means for them to switch from existing cooling units to the new generation.”