Innovative cloud technology with waste heat utilization concept

Learn more about OpenStack, the core of our Cloud infrastructure. Get comprehensive information about our innovative direct hot water cooling system and learn how to make use of the waste heat from our data centers to heat your office and to process hot water.

We cool our servers with water

Since the company was founded, we have been leveraging water cooling to cool our systems. We have been continually developing our technology over the last few years and are implementing an energy-efficient and cost-efficient hot-water direct cooling system in our latest generation of servers. A pump box developed by us carries 40 °C circulates hot water until a maximum temperature of 60 °C is reached. By adding the hot water to the company's local heating circuit, office and business premises can be heated cost-effectively and sustainably.

Why do we rely on the cooling medium "water"?

Air-conditioning is the largest energy user in the operation of a data center. Often they account for almost a third of the total energy demand. In contrast to conventional air cooling, the cooling capacity with water can be significantly increased. The heat absorption capacity of water is by a factor of 3300 and the thermal conductivity about 20 times higher than that of the air. Water can therefore absorb a lot more of heat - this effect is intensified by bringing the cooling medium closer to the heat source. In addition, the waste heat absorbed by the water can be made available for heating and hot water treatment. Especially in Germany, which is well above the average price level in European electricity price comparison, water cooling represents a not negligible alternative.

How does our innovative hot water cooling work?

Each server blade slot is equipped with a copper heat sink, which is located directly on the heat hotspots. Thanks to the direct cooling, a high packing density can be realized within the server rack and a considerable reduction in energy consumption can be achieved. The resulting heat can be derived directly from the CPU, RAM and chipset from the nodes by the hot cooling water. In this way, return temperatures of up to 60 °C can be reached, which can be reused on request for heating of real estate and for hot water supply.

The possibility of using server heat for hot water preparation and heating of real estate

Our patented technology includes a unique know-how in control technology and automatic control engineering. This allows high output temperatures with a very stable and fail-safe operation of our server. As a result, significant savings can be achieved both for server climate control and heating performance. For example, a total of 84 Cloud&Heat servers are used in our new Cloud site in Frankfurt am Main. By feeding the waste heat to the heating circuit of the building, up to 40,000 euros and heating energy can be saved each year - equivalent to a heating capacity for 150 low-energy houses. In addition, the direct, low-loss cooling of the servers saved approximately 30,000 euros of cooling costs every year.

Achievement of the world's lowest energy values

With our technology, we achieve unbeatable high energy efficiency. This is mainly due to water cooling and the absence of any refrigeration equipment. In our data center on Wallotstraße, we were able to reach a record PUE value of 1.026, which has been unbroken so far. The necessary cooling air is pre-heated by the adjoining underground car park, so that free cooling can take place all year.

Explanation of the CO2 calculations of the energy flow chart

According to the emission factors 2014 of the Federal Environment Agency [1], each kilowatt hour of electricity produced produces a carbon dioxide emission of 0.569 kg. Our data center with a current expansion stage of 60 % requires about 260 MWh of electricity per year, which would emit about 150 tons of CO2 if our data centers were not supplied with 100 % green electricity. In addition to these savings, further CO2 is saved through the sensible use of waste heat in the building. With every kilowatt hour of heat supplied, this amounts to 0.295 kilograms of carbon dioxide [2]. With a delivery of 100 MWh per year to the heating system, the data center saves about 30 tons of CO2 per year. Once the site has been fully expanded, it could even save 52 tons of CO2 per year.

Explanation PUE factor

The Power Usage Effectiveness factor, or PUE, is the ratio between total electrical energy consumption (i.e., the total energy consumption of the data center) and the electrical energy consumed by the IT hardware (such as servers and switches). The lower the PUE value, the higher the percentage of electrical energy used for IT. Correspondingly, less energy is "lost" for other systems such as cooling and lighting. The PUE value is always greater than one. The closer the value is to one, the lower is the additional consumption.

Explanation of the ERE value

Differently to the PUE factor, the Energy Reuse Effectiveness value, shortly ERE, additionally includes the re-used energy. Therefore, the value is most reasonable for evaluating the CO2 primary energy production. For this value, too, the golden rule is that the less the better. In classical data centers, in which the waste heat is not used, equals the ERE value the PUE factor.

We rely on OpenStack to build our cloud solutions.

Since 2012, we have been operating our own cloud infrastructure powered by OpenStack. We started with the Grizzly version and strive to always provide the latest OpenStack version for our customers. Over the years, we have acquired a broad know-how and comprehensive operational experience in this field. This allows us to play the full range of OpenStack functionalities, react to the individual needs of our customers and tailor customized and optimized cloud solutions. The free software project OpenStack is the basis of all our projects.

Why do we use OpenStack?

In recent years, OpenStack has become the de facto open-source standard for the operation of public and private clouds. OpenStack's particular strengths are demonstrated primarily in terms of flexibility and functionality. OpenStack's special strengths are demonstrated primarily in terms of flexibility and functionality. Compared to proprietary solutions, costs can be saved when using open source products. The OpenStack community, consisting of the world's best developers from renowned IT companies, contributes daily to the optimization and further development of the open source project.

Our contribution to optimizing OpenStack security.

During our 5-year operation, we have noticed a variety of security issues in OpenStack. These gaps provide hackers potential targets to permanently damage both cloud operators and their customers. In cooperation with a well-known German security company, we have subjected OpenStack to a comprehensive security check and developed mechanisms that can be used to close existing security gaps. These are subject to continuous control and optimization by our OpenStack core team. The knowledge we have generated flows into our own public-cloud infrastructure. However, they are also a standard part of all private cloud solutions.

OpenStack Lifecycle Management

Thanks to our OpenStack life cycle management, we have the possibility to install a virtual computer system very quickly and dynamically on different servers. We install the services we need to run OpenStack, such as Keystone, Neutron, View, Nova, Cinder, Ceph, Ceilometer, and Gnocchi. If required, each OpenStack installation can be flexibly extended by us or our customers, new servers can be dynamically added and upgraded.

You want to benefit from the advantages of our technology in your Cloud infrastructure?

Get in touch. We look forward to hearing from you.


Hendrik Fischer