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Cooperation - Seidl Technologies |
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1. Actively cooled server rack cabinet 1. Actively cooled server rack cabinet for the lower power segmentSeidl Technologies is looking for one or more partners, preferably but not necessarily from the European Union, to launch a product, which could be dealt with under the title Energetically reasonable one-cabinet data center with extremely low maintenance requirements. With such a product, we would like to fill a gap. The underlying idea is not fundamentally new. New is the focus, which is set here. As the analysis of the products of well-known manufacturers shows, there is little agreement in this regard. So we want to establish an Actively Cooled 19-inch Server Rack Cabinet in the market that is particularly suitable for small companies, medical offices, law and engineering firms, perhaps also for studios, and, that has a good price. In the case of smaller companies, the catalog of requirements with regard to such a product looks basically different from that of larger companies or data centers. In general, it is seen that, in smaller companies, it is accurately explored that an imagined procurement will advance some matter of importance and will do that for a very long time. 2. Needs and solutions from the technical point of viewIt is not always right to give data and their processing out of the hands. When it really comes down to it, it is necessary that data protection is physically enforced. This in its turn requires reliable, own hardware that cannot be accessed by strangers. The opinion about what one has to understand under reliable hardware changes with time, more precisely with the technological development. What, on the other hand, seems to be relatively steady is that reliably appearing hardware comes typically in the 19-inch format. And that is first of all a good thing. IT equipment in the 19-inch format can excellently be planned, installed and maintained. It is also undisputed that equipment in this format saves space, it is firstly stacked on top of one another and only then juxtaposed. Moreover, it is considered to be comparatively reliable, not necessarily because it works much better, but because it is usually uncompromisingly ventilated and most of the cables and connectors are protected from direct access. On the other hand, we have a number of drawbacks. Installed in office environments, 19-inch standard cabinets being full of equipment, more precisely, standard cabinets with significant energy conversion are perceived as very loud. Besides, they get polluted with time in a very unpleasant manner. Both the noise and the pollution are results of the strong and continuous gas exchange with the environment. The market takes neither the noise problem nor the dust one seriously. This is not really surprising. Well, in the huge halls of the data centers, the noise does not really matter and there is also no dust there. And since equipment, which is not intended for a data center, normally does not come to the customer in the 19-inch format, but in any cases of any size, geometry and color, and usually with a wall plug power supply, actually, there does not seem to be any reason to think about how a quiet and clean 19-inch cabinet should be built. This can be seen quite so. Furthermore, equipment encased in 19-inch standard cabinets gets quite fast unstable or dies the heat death when such a cabinet was placed in a possibly windowless broom chamber and someone has closed the door, even though the air inside there circulates well. Even a possibly existing air conditioner can only change this situation if the generated heat is actually removed from the chamber. But this is exactly that what is not done by products with a compact air conditioning unit. In addition, IT equipment in the 19-inch format costs significantly more than functionally equivalent one in a plastic or sheet metal box. And finally, there is interesting equipment that is not available in the 19-inch format at all. In spite of all the mentioned disadvantages, in 2005 we built an air-cooled cabinet, so to speak, as a first attempt, whereat it was initially not thought about its commercialization. This cabinet is still in operation today. The most important experiences and conclusions are the following ones.
Let us take into account all points touched. Our new cabinet, whose commercialization is intended, will be designed to provide a safe and unobtrusive home for almost everything of remotely controllable equipment being available in the IT market, to allow the housed equipment operating under favorable conditions, to run, apart from due UPS battery changes every three to five years, maintenance-free for something like a decade, to represent an energetically reasonable solution, to have a generally accepted price, and to enjoy itself a very long life. A complete package consisting of four apparently separable components wants to be delivered. Three of these four components are schematically shown in the above illustration. On the left we see the cabinet. It could be a symmetrical 19-inch standard cabinet, made from steel, with closed doors in the front and rear and the dimensions 42U × 600×1200 mm². The spacing between the front and rear mounting posts should be 800 mm. IP 54 is planned as the degree of protection. An optional anti-drumming kit should be offered to improve sound absorption. In the cabinet, the 8U air-water heat exchanger is located below. Above it there is the pump casing. On the right side of the illustration we have the water recooler. In our case, this is not a recooler with a chiller, that is a recooler with a machine performing thermodynamic cycles, but a common warm water convector radiator for living quarters, indeed a model of relatively high power. The third visible component is the tubing. With ½-inch armored hose, there is a pressure drop of approximately 0.3 bar at 5 ℓ/min volume flow rate and 40 m length. In approximation, the pressure drop increases with the square of the volume flow rate and linearly with the length. For further orientation, the water temperature rise is little less than 3 K at 5 ℓ/min volume flow rate and 1 kW total dissipation power. The fourth and last component, a small control device, is not represented in the illustration. It can be seen what should happen here. The problem case, the standard server rack cabinet with its characteristics large, loud, heat and dust sensitive is smashed into two parts, which can more easily be controlled. A water-cooled server rack cabinet can be placed practically everywhere, in particular into the mentioned dark broom chamber, whose door could be specially secured for this purpose. Within the cabinet, comparatively high air volume flow rates can be realized to care for smallest air temperature rises. Concerning the space consumption, practically nothing changes. The cabinet will be aligned with one of its side panels towards a wall. Before and behind the cabinet, the necessary maneuvering space must, now like before, be reserved, which, however, can be occupied by easily movable objects since the experience shows that a server rack cabinet need be opened less frequently than once a year. With 21U for servers and storage, there is quite an amount of space available such that different concepts can be considered. One point is thereby, of course, that everything can be switched on and off from the outside. The warm water radiator will, on the other hand, be installed where it is most appropriate. It makes no noise and heats the room which it is in. It should therefore not be covered. There will be several questions. A first is surely the one of the reason why a warm water radiator should be used here instead of a water recooler with a chiller, or, again, instead of a water recooler with a machine performing thermodynamic cycles. For the intended solution, two circumstances speak first of all. Firstly, it would be very difficult to communicate to our target customer group that there is a need for a device, weighing 30 to 70 kg and put-putting permanently or intermittently around, to properly operate some servers that should replace the up to now somehow put up computers of a customer. And where, if necessary, should such a device find its place in an office, perhaps in the kitchenette? Secondly, in a data center with its enormous power densities, there is hardly any other way than to spend one more amount of electrical energy for cooling that is almost of the same order of magnitude as the one being used to supply the equipment itself. The recoolers used there are at the same time much more efficient than any 1 kW model. In addition, data centers as large consumers are relatively favorably tariffed, whereas the final result of the German energy policy for the consumer is a kilowatt-hour price for electrical energy around ⅓ €. One consequence is that a usual tower case computer installed in an office must not consume more electrical energy for its cooling than that for a few fans. The same rule should basically be applied to the servers in our cabinet, too. Such an argument speaks even more against a water recooler with a chiller. In addition, the situation can be seen from a completely different angle. IT equipment transforms electrical energy into heat. In many parts of the world, this heat can almost all the year round be used to heat the rooms, which means that the electrical energy is used to turn bits in the processors as well as to move bytes, and, on the other hand, to heat the house. So the balance is better than is commonly assumed, but of course only with the warm water radiator. In other parts of the world with perhaps 45°C outside temperature, IT equipment can normally not be operated without the support of refrigeration machines. But also in these areas, it can be sensible to get rid of the heat through a warm water radiator directly to the office, which is often cooled down to 18°C. It is thus possible to dispose of the heat without great circumstances via the building air-conditioning system. So there is something that speaks for the warm water radiator with its two great advantages, not making noise and being almost maintenance free. Nevertheless, we will design the air-water heat exchanger in such a way that condensate drainage is perfectly mastered, too, so that the cabinet can also be operated with a recooler with a refrigeration machine. Those customers who want to cool in this manner will, of course, abdicate the pump casing over the air-water heat exchanger. Further questions arise. Probably the most important point is to find out under what conditions the whole installation really works. For that we apply a method called Design of Experiments with its brute-force variant Full Factorial Design, whereat the experiments are replaced by computer simulations. Results obtained in this way can be illustrated in a special graph. First of all, however, is to be clarified what is calculated. The cold air flow indicated on the left in the above illustration is uniformly distributed over a very large number of imaginary, identical rack mount drawer units of infinitesimal height. A first, binary influencing factor determines whether the cold air flow is only distributed over the units being switched on, or over all the units, where a maximum of 10⁄13 of all units can be switched on. The air volume flow inside the units being switched on is selected via a further, binary influencing factor such that the air temperature rise equals either 3.3 K or twice that value. The volumetric flow rate through the units being switched off is, as long as it differs from zero, the same as the one through the units being switched on. The air, emerging from the units on the right, gets mixed and yields the warm air. The calculations concerning the air-water heat exchanger are controlled by means of two further influencing factors. A first, again binary one determines whether the quotient of the temperature difference between cold air and cold water for cocurrent flow and the same temperature difference for countercurrent flow should equal 1.82 or 1.42 . The air-water heat exchanger itself is, of course, operated countercurrently. The second, ternary influencing factor determines the contact surface of the air-water heat exchanger. The latter can be 2A, 3A, or 4A, where A is slightly more than 5m². A further influencing factor determines the volume flow rate of the cooling water, 150, 300, or 600 ℓ/h. Finally, a last, ternary influencing factor determines the nominal power of the warm water radiator. This can equal 3, 6, or 12 kW. The following graph shows the most important results. Shown is the very important difference between the temperature of the air, exiting one of the switched-on rack mount drawer units on the right, and the ambient temperature at the installation location of the warm water radiator, and this temperature difference above the overall consumed electrical power being transformed into a heat flow rate out of the cabinet. Parameters are the mentioned influencing factors. For the maximum permissible value of the temperature on the output side of a switched-on rack mount drawer unit, we take the value of 40°C, which was once given by Intel for the maximum permissible operating temperature of mainboards. This value is not irrefutable, but it coincides with long lasting experiences with consumer-level products made by different manufacturers. In short, up to 40°C board temperature, there is not the slightest complaint in terms of stability when using ECC memory. Further, the offices of Seidl Technologies, as an example, have south-facing windows and are not air-conditioned. Therefore, the temperature there can just rise once to 30°C in summer. If one of these offices is now also the location of the warm water radiator, then all permissible operating conditions of the installation can directly be read out. Thus, at 30°C, everything below the horizontal 10 K line is allowed. Correspondingly, at 28°C maximum office temperature, everything would be allowed that was below the horizontal line at 12 K. We come to explain the influencing factors. Obviously, the curves in magenta (), in brown (), and in cyan () belong to 6.6 K air temperature rise within a switched-on rack mount drawer unit, while the curves in red (), in green (), and in blue () belong to 3.3 K. On the other hand, the curves in magenta () and in red () belong to 3 kW nominal warm water radiator heat power, the curves in brown () and in green () to 6 kW, and the curves in cyan () and in blue () to 2×6 kW. As a reminder, the nominal warm water radiator heat power here refers to the EN442 standard conditions 75°C / 65°C / 20°C, and a radiator exponent of 4⁄3 has been assumed. As expected, the nominal warm water radiator heat power dominates the situation. Besides, the air temperature rise in the rack mount drawer units should be kept at values of about 3 K. With the comparatively low power densities here, this is not a problem at all. Seen from the point of view of the approach, working on one of the green lines is favored, id est, with a single warm water radiator as described above. Hence, ambient temperatures of 30°C still allow 400 W power consumption in the cabinet, those of 28°C already 600 W, and those of 23°C the full kilowatt. In certain circumstances, the warm water radiator can be placed in a larger stairwell or basement, such that outsiders do not get access to it, or, if the space conditions permit that, two 6 kW models can too be connected in series. With two 6 kW models in series, even 800 W are still possible at 30°C in the environment. It should also be mentioned that the air-water heat exchanger should possess a certain minimum value with regard to its heat capacity to cushion impacts caused by cooling water circuit disasters. It should further be noted that temporal temperature changes should not exceed a rate of 20 K/h as long as massive hard disk accesses occur. Of course, this last condition can also most easily be fulfilled with two 6 kW models in series. 3. Commercial aspectsThere is no doubt that there are customers for the solution presented. The problems are everywhere the same and to rely on the 19-inch format is as consequent as reasonable. What the experience, however, quite clearly shows is that, outside of data centers, the usability of 19-inch data center equipment is rather limited, and that 19-inch equipment, which is intended for customers outside of data centers, does not meet the needs the envisaged target customer group really has. Against such a backdrop, we want to offer an energetically reasonable one-cabinet data center with extremely low maintenance requirements, and we want to have commercial success with it. Such a one-cabinet data center is therefore certainly not a product for which the components can easily be gathered together. Such a one-cabinet data center is a product consisting of different, partly multiply existing components, of which at least six have to be specially manufactured here. These six components, which have to be specially manufactured, are the air-water heat exchanger, the pump casing, the mentioned Reverse Flow Blockers, the special rack chassis, the small control device, and the optional anti-drumming kit to improve sound absorption. Of course, as in the case of the air-cooled variant, the devil is also in the detail here. Two prototypes should soon be built. This requires funds that Seidl Technologies alone does not have. When it comes to prototype construction, our aim is not only to ensure that the design of the components to be manufactured turns out suitable and cost-effective, but also to permit the separate marketability of at least the air-water heat exchanger, the special rack chassis, and the Reverse Flow Blockers. Perhaps even the pump casing is salable if it is offered together with air-water heat exchanger, one will see. For the special rack chassis, also data centers are seen as a target customer group if they are going to eliminate their messy corners. Finally, the competitors, too, which at the moment are, of course, not yet existing, could be considered as a target customer group for all the components to be manufactured. In summary, our main objective here is to find a highly productive metal construction company with certain qualifications in the electronic and electrical engineering sector, which has the will and the strength to tackle the outlined project together with us. How the cooperation in this case actually turns out will surely be subject of negotiations. Alternatively, if you think that we have a good thing on here, there is always the possibility to push the prototyping through direct financial contributions. Just contact us. A solid way to prepare contacts with us is the one via the Customer data form. Please forgive the circumstance that it is still seen that this form was originally only intended to prepare business relations with customers. As a potential partner you will surely expand the part Cooperation in this form. 4. About this pageThis page has been online since January the 9th, 2017. The present release of this page is the version 3 of August the 10th, 2020. |
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