DCN April 2016 - Page 41

structured testing distribution, with direct connection to PDUs. This type of load is unsuitable for data centres that have some or all of the IT racks deployed. We recommend for optimum testing that the heat load should be sized and distributed to replicate the IT layout and be connected to the power distribution. Typically heatload.co.uk is engaged during levels 4 and 5 of data centre testing; teaming up with a number of partners who are able to provide load banks in support of level 1 to 3. Test the computational fluid dynamics (CFD) mode l chillers, generators, transformers and UPS individually and as a system. Level 4 and 5 testing brings together all of the combined power and cooling systems supporting the data centre, as well as life safety, security etc. The testing requires the load to be located within the IT space and much more granular in terms of size, location and capacity of the load banks. The load banks should replicate the final layout and capacity of the IT equipment. There is a temptation to fill the data centre with large space heaters, each of 50kw of more. This type of load is fine for testing the total capacity of the room. However, it is not suitable for room validation or testing the IT layout. Larger capacity units are likely to bypass the power It is likely that the design has been tested using computational fluid dynamics (CFD) modelling tools. Level 5 testing should include room validation that proves the model. This will give the end user of the facility full confidence in the model. Once the data centre is operational it is unlikely that further heat load testing can be achieved; so changes in the IT infrastructure should be modelled to fully understand the impact to the data centre. The best way of proving the model is to fully replicate the heat load layout. This means using heat load that replicates that of the model and fully monitoring the testing using temperature sensors. Ideally the data centre should be flooded with temperature sensors, with multiple sensors at the front and rear of every rack location. Recent integration between the sensor manufacturer’s capture software and the CFD modelling software allows real time modelling, using real data. The original predictive model can then be compared with the real time one. During 2016 heatload.co.uk is looking to offer this as a service. Test at different IT capacities The temptation is to just test the data centre at 100 per cent IT capacity because IT has specified the load and migration of IT equipment will be rapid. This is not always the case. IT may have overspecified the IT load and the migration plan might be too aggressive for the end users. 41