Many people associate Marketing purely with advertising, and this is a misconception. Rather, its mission is to lend the company a corporate identity that extends from its products to external and internal communications. To do this, it must continuously keep an eye on the market and the competition, and ensure that the STULZ brand is kept constantly up-to-date in the minds of potential and existing customers. It does this on the internet – on the website and social media, for instance – and through PR work. It is pursuing a permanent and ongoing objective.

Unlike in other departments, here nearly everyone does something different and is an expert in their field – there is hardly any overlap. And precisely because of this, continual communication and keeping each other up to speed are especially important. I have rarely seen as much internal communication as in Marketing.

The Monday meetings, lasting roughly an hour, are key to this exchange. Here, everyone reports on what they are currently working on and how projects are progressing. I was also able to attend these meetings, which doesn't go without saying for an apprentice, but it enabled me to understand better how the various strands of the department are interconnected.

Marketing colleagues also often get together outside the Monday meetings to exchange information and gain a bit of advice now and then. Although everyone is always extremely busy, they are always ready to lend an ear to other colleagues.

I was also entrusted with projects for which I alone was responsible.

One of these involved making an Advent calendar, which was then projected onto the large factory building as a PowerPoint presentation, and was hopefully enjoyed by colleagues. Contrary to my expectations, gathering ideas to ensure a good input was easy, and it was the design that took more work. I did of course receive support with this project. Our Group Leader for Communications helped me with planning and contributed ideas for the content. For its design, I approached our graphic designer, explained my ideas and he then made these a visual reality.

Aside from this project, I was always being given smaller jobs to do from the various areas of Marketing, which also helped me to better comprehend the operational running of the department.

At any rate, Marketing is a department the importance of which cannot be underestimated, where a working day flies by and you can learn a great deal.

Over 9000 sqm of state-of-the-art technology for STULZ S.p.A.

We are glad to announce the opening of our new production plant, officially presented during a ceremony held on the 27th of September 2016.

To loosely quote DIN EN 50600 (also see "Data centre standard DIN EN 50600 (VDE 0801-600) in brief"), the raised floor is a system consisting of completely removable and exchangeable floor grills fitted onto adjustable base frames, which are interconnected by beams. Its purpose is to make the space under the floor available for facility services.

Now as ever, precision air conditioning units (CRAC or CRAH) are still the first choice for air conditioning data centers, even now in the age of in-row cooling, rack cooling and air handling units. This article does not go into the reasons for this. Instead, it deals with the raised floor which, in conjunction with precision air conditioning units, ensures maximum reliability and efficiency.

In the past, the raised floor concealed "facility services" such as power cables, data cables and piping, and the cold air had to painstakingly find its way through these to the air outlets. A good deal has changed since then. It is now common knowledge that the primary aim of the raised floor is to convey cold air to the servers, and so wiring is mostly routed above the racks. In addition, these days the height of the raised floor is planned to ensure that the air in this supply air duct has sufficient space to reach its destination without major losses or resistance.

It is vital that a raised floor is leak-proof if it is to be used for air distribution. Care must be taken to ensure that the cold air only leaves the raised floor in the direction of the servers where planned and where most effective. Leaks in cable glands, beneath racks or at wall connections must be meticulously sealed. Raised floor grills that are removed for maintenance purposes are a hindrance to air distribution. This should be reduced to the necessary minimum.

Let's explore 10 Important Data Center Best Practices:

Along with the chilled water heat exchanger and fans, the chilled water control valve is the other principal mechanical component of a CW precision air conditioning unit. In the past, either 3 or 2-way control valves were used, depending on the type of hydraulic system and pump used (variable or constant speed). However, for some time now so-called "pressure independent control valves" or "PICVs" have also been frequently used as 2-way control valves or ball valves.

In order to better understand the method of operation and advantages of the PICV, we would do well to recall some fundamental hydraulic principles:

1. A control valve ensures that a heat exchanger is always supplied with the correct quantity of water for the current operating point or cooling needs (full load or partial load). The appropriate valve position or degree of opening is determined by an external control signal.
   
   
2. The valve size (keywords: Kvs value, Valve Authority) must be based on the required quantity of water (full load operation) and the water-side pressure drop at the heat exchanger.
   
   
3. The pressure drop at the control valve resulting from the valve calculation is also referred to as "differential pressure". This differential pressure and the pressure drop at the heat exchanger must be correctly harmonized with one another:
   
   
   • Differential pressure too low (valve too large): the valve has only a small stroke range, with adverse effects on control quality and unstable control behavior (fluctuations) as possible consequences
   • Differential pressure too high (= valve too small): major noise and cavitation possible, superfluous pump energy consumed
     
     
4. In every hydraulic system, pressure through the valves, heat exchanger and pipes vary depending on the type of system, installation location and distance from the pump, as well as on changing load conditions.
   
   
5. The definitive factor when determining the size and settings of the pump is to make sure that the last consumer in the system is always supplied with the necessary quantity of water at full load, and that the associated differential pressure can be surmounted.
   
   
6. The closer a consumer (e.g. a CW precision air conditioning unit) is situated to the pump, the greater the flow rate and, without so-called "hydraulic balancing", the differential pressure through the control valve of this consumer will also rise. Hydraulic balancing makes sure that each consumer in the system always receives the required quantity of water, and that the water does not take the path of least resistance.

But what is the role of the pressure independent control valve here?

A modern electronic pressure independent control valve basically always combines four functions in one valve unit – pressure independent control, measurement of the water flow, a shut-off function, and automatic hydraulic balancing. These functions are performed by the control ball valve, valve drive and flow sensor.

This means that in a pressure independent control valve, the setpoint is always the required water flow rate. Since the current flow is measured continuously, the valve adapts the required quantity of water in line with the load, and the valve's pressure drop (differential pressure) is therefore the result of the flow rate, not defined by valve size or the kvs value. Consequently, any difference between the setpoint and the current flow due to a change in differential pressure is compensated fully automatically by the opening angle of the control ball valve.

So "pressure independent" (or more accurately, "independent from differential pressure") means that the correct amount of water is always supplied to the consumer, and the control quality is dependent neither on the valve's position in the hydraulic system nor the prevailing pressure conditions.

Advantages of a pressure independent control valve of this kind

1. Planning/design:

• Fast and simple valve design based only on the required quantity of water – kvs values, Valve Authority and varying differential pressures can basically be ignored
• No balancing valves or circuit control valves needed – lower investment and installation costs

2. Start-up/operation:

• No balancing valves or circuit control valves needed – therefore lower water-side pressure drops and the possibility of reduced pump power consumption.
• No time-consuming, labor intensive hydraulic balancing required – the pressure independent control valve performs the task of hydraulic balancing; the required quantity of water is adjusted easily
• Stable and precise control in all load states thanks to the defined quantity of water, regardless of the type of hydraulic system chosen
• Water quantity can be flexibly adjusted in the event of extensions, conversions and/or modernization
• Water quantity can be easily read – more in-depth analysis (e.g. cooling capacity) is possible It is clear that the use of so-called pressure independent control valves makes sense in most cases, as investment and operating costs can be lowered, and stable control is guaranteed irrespective of the chosen hydraulic system and current load conditions.

It is clear that the use of so-called pressure independent control valves makes sense in most cases, as investment and operating costs can be lowered, and stable control is guaranteed irrespective of the chosen hydraulic system and current load conditions.

Gross cooling capacity is produced by the air conditioning unit via the heat exchanger. Fans are used to move the air through the air conditioning unit. These consume energy, which is ultimately converted into heat. This heat, also produced in the air conditioning unit, lowers the gross cooling capacity. The result is the net cooling capacity.

Modern precision air conditioning units cool the air without dehumidifying it. All the cooling capacity generated is therefore used precisely for what is actually needed: cooling the air. In older air conditioning units and those with components not of an ideal size, or with a bad choice of return air conditions, it can happen that some of the generated cooling capacity is inadvertently used to dehumidify the air during the cooling process. Valuable cooling capacity is lost and the air conditioning unit works less efficiently. The entire sum of cooling capacity generated is known as the total cooling capacity. The proportion that is used for purposely cooling the air is called sensible cooling capacity. Any proportion of the cooling capacity inadvertently used to dehumidify the air is called latent cooling capacity. In an ideal situation with no unwanted dehumidification, sensible cooling capacity is the same as the total cooling capacity. The ratio of sensible cooling capacity to total cooling capacity is referred to as the "sensible heat ratio", or SHR for short. In ideal conditions without dehumidification, the SHR is generally 1.0.

So as we can see, it is vital to take care to compare like with like when comparing technical data. If you are unsure whether the manufacturer documentation is talking about total gross cooling capacity or the effective, usable sensible net cooling capacity, it makes sense to ask before comparing data from different manufacturers.

However, in most cases the air is not regulated as it exits the raised floor. Here, sensor-controlled raised floor grilles with a variable opening angle are an essential element for restricting the energy consumption of the air conditioning system.

In the majority of cases, the raised floor manufacturer also provides the grilles for the outflow of air. As a rule, the customer can then choose between different degrees of perforation. Some manufacturers also offer restrictor panels, which are fitted to the underside of the floor grille and enable the airflow to be regulated manually.

The actual airflow rate required depends on the current load of the server. However, in this age of server virtualization and cloud technology, load fluctuations can occur as entire racks are switched on and off. Due to this fluctuating server load, flexible solutions are also in demand for closed-circuit air conditioning. The challenge lies in supplying the servers with sufficient cooled air that is targeted in line with demand.

Here, 'sufficient' means that precisely the amount of air needed at that moment by the servers exits the raised floor and 'targeted' means that as far as possible, the air exits the raised floor directly in front of the server rack's air intake. This last point is especially important when the cold and hot aisles are not separated by walls or partitions. The demand-based supply of cold air immediately in front of the server intake keeps the mixing of cold and hot air to a minimum. We can therefore refer to this concept as virtual containment.

With the AirModulator, STULZ offers a solution for a large variety of applications, and with dimensions of 600 mm x 600 mm that make it compatible with commercially available raised floors. The opening angle of the dampers can be regulated to suit demand by the building services management (BMS) system, or by the AirModulator's own controller, based on the temperature or pressure difference. In the event of a power failure, the dampers are opened automatically by a return spring. The unit as a whole is finished with a flow optimized grille, and is therefore also protected from mechanical stress, e.g. from lift trucks.

STULZ GmbH, a German multinational Company specialised in the manufacture and the commercialization of precision air-conditioning equipment, announced today the purchase of the 100 % of the Tecnivel Spanish Group shareholders, a leading manufacturer in industrial air-conditioning and cooling solutions in Spain.

Hamburg, 2016/7/26 – With the Explorer WSW STULZ offers a water-cooled chiller for a wide range of performance-critical applications. This flexible chiller can be easily adjusted to different heat loads thanks to its two refrigerant circuits with semi-hermetic screw compressors and infinitely variable output sliders. Its application areas range from industrial cooling through data centers and telecommunications to chilling for the hospitality sector and commercial buildings. Depending on the required cooling capacity, the chillers in the STULZ Explorer series can be equipped with either one (230 to 430 kW) or two compressors (460 to 1,530 kW). The chillers feature shell & tube condensers and can be set to operate at different temperature levels, for example with well water, cooling towers or external recooling heat exchangers. The evaporation process in the refrigerant circuit is controlled by electronic expansion valves, which use pressure sensors, temperature sensors and the STULZ C2020 controller to optimize heat exchange between the refrigerant and chilled water in the evaporator. 

When developing the Explorer product range, the priorities included a compact, corrosion-resistant design as well as low noise emissions. A low-noise version is also available for especially noise-critical applications. Extra acoustic insulation here allows the sound power level as per ISO 3744 to be reduced further by up to 10 dB. Thanks to its versatility in terms of applications, the STULZ Explorer WSW also impresses with high efficiency in partial load mode. Depending on the service conditions, it can offer ESEER values of 5 and higher. In line with its wide range of applications, the STULZ Explorer series also offers a variety of options such as automatic transfer switch, an energy meter for measuring total power consumption, soft start and anti-vibration mounts.

For more details please visit our product page.

Most users and planners are now aware that temperature levels when cooling IT equipment in data centers have changed dramatically in recent years.

The main reason for the adjustment of air temperatures is ASHRAE recommendation TC 9.9 2011, which recommends air inlet temperatures to IT equipment in a range from 18 °C up to a maximum of 27 °C. Adding an average temperature difference as air flows through the IT equipment of 10-15 K, this produces return air flow temperatures back to the A/C unit in the range from 28 °C to 42 °C (see blog article "Delta T"). The actually most important "side-effect" of this recommendation, however, is utilization of so-called "free cooling" – that is, cooling of IT equipment as far as possible without the energy-intensive use of compression cooling (see blog article "Free cooling").