The Mega data centre IST challenge

DATACENTRE.ME FEATURED ARTICLE: Hillstone CEO Paul Smethurst highlights the issues of Load bank testing 100MW data centres

The insatiable demand for data and the growth of cloud based services has changed the European data centre landscape with the arrival of the MEGA DATA CENTRE.

The Mega Data centre allows global software giants like Microsoft, Google and Apple to provide our day to day IT services.  The Mega Data centre is also the foundation for colocation providers such as Digital Reality Trust, Equinix, Telecity and Interxion to facilitate connectivity to the cloud for multi-national conglomerates in banking, oil & gas and telecoms.

This rapid expansion of cloud services has created the challenge of how to commission Mega Data centres of 20MW, 40MW, 80MW and 100MW.

Historically the largest ever load bank projects have been in the Oil & Gas sector and used 50-70MW of containerised load banks.  These load banks would be situated outdoors as part of very large temporary generator power projects. 

Fortunately the evolution of the Mega Data centre as taken a practical modular build approach, with role out phases of dual halls at 2500KW or as a single 5000KW empty white space. Such a reduction in rating does not however reduce the challenges of sourcing the quantity of required load banks needed to complete the Integrated System Testing ( IST )

The primary objective for data hall IST commissioning is to verify the mechanical and electrical systems under full load  operating conditions, maintenance and failure scenarios to understanding that the data hall is ready for deployment of active equipment.

Today’s IST requires a package of equipment which will closely replicate the data hall when in live operation.  Server Simulators load banks, flexible Cable Distribution, Automatic Transfer Switches, data logging for electrical power,  environmental conditions ( temperature & humidity ) and the ability to incorporating the load banks within temporary hot aisle separation partitions give the foundations for a successful IST.  These tools allow the commissioning report to present a CFD model of the actual data hall operation during IST.

The selection and use of Server simulators, typically rated between 3KW to 6KW as per the expected IT rack loads, give an even granular distribution of low delta temperature across the data hall.  Such detailed consideration of air distribution during the tests is required due to the scale of the IST and the increased volumes of air affected in the Mega Data Centre environment

This replicated heat allows the mechanical cooling systems to run at optimum design temperature to verifying the operation of room is without any hot spots which ensures deployment of future active IT equipment will not overheat and fail. 

Server simulators can also be used if the commissioning occurs prior to deployment of IT cabinets, by being housed in portable mini-towers for distribution across the empty space.

The requirement for using flexible Cable Distribution facilitates the ease of cabling a high quantity of 5KW to 20KW rated load banks to A & B feeds on PDU or bus bars infrastructure.  The ability to manually transfer the load between supplies simplifies the balancing of the loads and eliminates one of the biggest problems in setting up a IST.  If the cable distribution also includes the ability to automatically transfer the load the commissioning team can replicate maintenance procedures and failure scenarios during the IST

In order to report the successful operation and performance of the room during the IST, the commissioning team will need to monitor & record electrical and environmental data.  Having electrical data logging and viewing available within the load package avoids the use of a power analyser with exposed connections to live terminals in the data hall.  When server simulators include temperature sensors extensive temperature analysis allow CFD modeling to be performed of the testing period.

Whilst the data centre will ultimately have a BMS and the data hall fitted out with the latest DCIM system, they are unlikely to be fully operational at the time of the testing. 

The project team should source a provider offering only server simulators at the earliest opportunity in the project and avoid alternative load bank solutions that will cause delays to the IST program

Common mistakes in load bank selection:

The restricted choices in the market dilutes the availability of load bank choices and equipment.  Decisions to select on cost the wrong type of load bank solution can compromise the validity of the IST but the unknown hidden problems will not manifest until the data hall goes live with active IT equipment. 

The temptation to choose 20KW 3 phase industrial space heaters rather than server simulators load banks effects the commissioning of mechanical cooling systems.  The design of such heaters, having thermostatic temperature controls, creates lumpy load during the on & off cycling needed to protect the unit from over-heating. These heaters prevent the elevation of the data hall ambient room temperature reaching the design criteria needed to commission the CRAC or AUH units.  Some suppliers have reported they have removed the thermostatic controls only to find the space heater over heat and in some circumstance have caught fire due to being operated outside the intended product design and operation. 

The choice of large 110KW load banks can be justified when testing site equipment such as PDU panels, bus bars or switchboards to Level 3 ASHRAE requirements.  These load banks provide a cost effective solution to  proving the electrical infrastructure of the Mega Data centres however they will create localised hotspots or areas of concentrated heat should they be used for the commissioning of the cooling systems.

In extreme circumstances it has been observed during Tier certification the electrical load has been provided from 2KW infra red heaters or 1KW hair dryers.  Infra red heaters create an ambient temperature of >40oC and wall skin temperatures of 70oC.  Hair dryers become a fire risk as they are not designed for continuous operation as required in an IST.  These type of low cost solutions are should not be considered to replicate the operation of IT equipment and risk costly delays and comprise the integrity of the testing program. 

Raising the bar:

Hillstone have many years experience of data centre load bank testing across UK, mainland Europe and the Middle East and have developed a data centre testing load bank package designed to remove many issues experienced in such commissioning projects.  These solutions include:

·       6KW 19” rack server simulators

·       Environmental temperature and humidity data logging

·       20KW mini-towers

·       Automatic transfer switch distribution units with electrical load data logging

·       Enhanced IST reporting with CFD modelling of the environmental room performance

The Hillstone HAC230-6RM has also become the industry choice of server simulator and it provides a true replication of expected airflow draw from a blade server.  The 6RM is design in a light weight 4U size to allow one man to populate it into an IT cabinet, with the flexibility of connecting to either single phase or 3 phase PDU power strips. 

The Hillstone mini-tower, HMT-20, is a portable data centre load bank designed to deliver a balanced distributed heat of 20KW load.  The HMT-20 holds 3 6RM server simulators to replicate the airflow expected in IT cabinets.

The flexibility of the HMT-20 allows connectivity to either single or 3 phase sockets and when used with our cable floor tile the total solution prevents any loss of air pressure losses when connecting to under floor sockets

The Hillstone ATS is the latest addition to the offered data centre load bank solution.  The ATS has been designed to switch up to 6 x HMT-20 and incorporates Cable Distribution, manual load balancing, summation power metering and data-logging of the total room under test. 

The data logging option, when used in data halls without power metering, will save significant time and resources on the electrical surveys

Achieving Cost savings:

Completing an IST to budget takes a greater importance when commissioning a Mega data centre, especially with the number of rental load banks that will be required.  The increase in size of the facility will increase the time needed to complete the commissioning so by combining the latest technologies traditional delays associated with load banks can now be avoided.

By selecting solutions which give enhanced Data Logging, the commissioning report will give the client detailed levels of operating information and fully auditable reports for future tenants considering use of the space.

Data logging can also be used in CFD models and therefore the upmost confidence that the Mega data centre is ready to use.

Hillstone are a UK manufacturer of load banks.  The first load bank was designed in 1989 and the company continues to provide worldwide customers innovative solutions to load testing.  The rental division and data centre service team provide an unrivalled delivery of load banks in UK, Europe & Middle East.

For more information please visit www.hillstone.co.uk, email sales@hillstone.co.uk or call Paul Smethurst on +44 (0) 161 763 3100

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