CFD Beyond the Whitespace. Datacentres Central & Eastern Europe

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1 CFD Beyond the Whitespace Datacentres Central & Eastern Europe September 2013

2 CONTENTS 1.0 Introduction 2.0 What is CFD? How it Works CFD in Data Centres 3.0 CFD Outside the White Space Case Study 4.0 Why is it Important Case Study 5.0 Conclusion

3 INTRODUCTION Conceptual Design Name: Alex Nock Position: Head of Building Physics Employer: RED Engineering Design Education: BEng Electromechanical Engineering MSc Management Science & Finance Energy Modelling CFD

Engineering Design Education: BEng Electromechanical

4 INTRODUCTION TO RED RED Engineering is a multi-award winning building services practice delivering MEP engineering design services globally with a focus on local delivery Established in 2004 Currently 140 staff worldwide Regional headquarters in the UK, UAE and the newly-opened Istanbul and Singapore offices serving projects in Europe, North Africa, the Middle East, India and the Far East RED designs MEP services for infrastructure, new buildings and upgrade projects, with a focus on innovative, low energy solutions. RED designs for mixed-use projects, data centres, offices, hotels, residential, retail and high rise. Awarded globally for our low energy and innovative designs Designed & delivered some of the most energy efficient data centres in the world The first two Uptime Institute accredited tier designers in the UK Designed & delivered 4 of the UK s tier certified data centres Leading the field in the advancement of modular data centres

East RED designs MEP services for infrastructure, new buildings and upgrade projects, with a focus on innovative, low energy solutions.

5 WHAT IS CFD? Computational Fluid Dynamics or CFD is a technique used by Formula 1 teams and the aerospace industry for many years. Using software, complex air flows, temperatures and pressures can be modelled such that the interaction between items of plant, equipment and their environment can be accurately predicted. CFD enables a design to be fully tested and proven in a virtual environment before being put into production. Over the last few years the use of CFD within the data centre sector has grown rapidly and it is now becoming an increasingly popular and important design tool.

environment can be accurately predicted.

6 HOW IT WORKS The CFDSolver takes a computational representation of the model... It iteratively solves the many simultaneous equations representing the Conservation Equations or Navier-Stokes Equations which define the mass, momentum and energy on a three dimensional array of points, defined by the superimposed grid or mesh, with a view to solving the equations numerically, which by themselves have no analytic solution.

Navier-Stokes Equations which define the mass, momentum and energy on a three dimensional array of

7 HOW IT WORKS (SIMPLIFIED) Let the software do the hard work Build a 3D Model 2. Specify environment and behaviour of items inside the model 3. Press Solve... and in the Background... The scale model within the software is then diced into micro proportions through a 3 dimensional grid, each portion or cell is then examined with iterative calculations for the following variables, until a steady state solution is achieved X Velocity Y Velocity Z Velocity Temperature Pressure Kinetic Energy Turbulence Dispersion Rate Relative Humidity RED use the Future Facilities 6Sigma suite of software. This industry leading software package is designed specifically to capture the resolution and level of detail required to analyse mission critical facilities such as data centres.

variables, until a steady state solution is achieved X Velocity Y Velocity Z Velocity Temperature Pressure Kinetic Energy Turbulence Dispersion Rate Relative Humidity RED use the Future

8 CFD IN DATA CENTRES New Data Centres: White Space Analysis Data hall design verification Analyse the performance of unproven data hall designs to ensure even cooling distribution and modelling different control strategies. Transient response analysis to data hall cooling system failures Time dependant, second by second simulation of a data halls response to any cooling system failure. T =? Minutes

9 CFD IN DATA CENTRES Existing Data Centres: White Space Analysis Analysis of existing data hall facilities Survey the facility and investigate the operation of the existing data hall installations down to a server by server level of analysis, highlighting any hot spots, areas of recirculation and overheating. Ongoing data hall management and expansion strategies Advise on the placement of new equipment within the data hall, how to manage the facilities future expansion by simulating the installation of new servers in their optimal location and examining the effect of these on their surroundings.

10 CFD OUTSIDE THE WHITESPACE

11 CFD OUTSIDE THE WHITESPACE

12 CFD OUTSIDE THE WHITESPACE

13 CFD OUTSIDE THE WHITESPACE

14 CFD OUTSIDE THE WHITESPACE

15 CFD OUTSIDE THE WHITESPACE

16 CFD OUTSIDE THE WHITESPACE Plant room modelling Air flow and cooling analysis of critical equipment such as UPS, transformers and switchgear to ensure their environment remains within the constraints determined by the manufacturer. External plant compound modelling Analysis of external plant performance under different ambient conditions and wind strengths, illustrating how different items of plant interact with their environment.

17 CASE STUDY Project Requirements: Client requirement for a minimum of 4,000m 2 technical white space at 2kW/m 2. System design requirement of Uptime Tier III concurrent maintainability. BREEAM Excellent for Data Centres Planning acoustic requirement to be designed for 10dB below the background noise level at the nearest residential property resulting in a required noise level of 30dBA at 10m. Planning Requirement for a 20% onsite renewable energy including Data Centre process load. Building height and volume restrictions at inner city location.

BREEAM Excellent for Data Centres Planning acoustic requirement to be designed for 10dB below the background noise level at the nearest

18 CASE STUDY Proposed Design: Chilled water system with economiser. Water cooled Turbocor chillers with roof mounted adiabatic coolers (free cooling air cooled chillers too noisy and insufficient roof space for desired IT load). Elevated chilled water temperatures and the available area for heat rejection plant maximised to create the optimal free cooling performance. Plant room generators with remote radiators to reduce noise emissions from the facility. Manufacturers recommended separation between plant

insufficient roof space for desired IT load).

19 CASE STUDY 35 o C Peak Ambient Condition on a Still Day:

20 CASE STUDY 35 o C Peak Ambient Temperature and Max Wind Strength on that Day

21 CASE STUDY What to do? Insufficient vertical separation between generator exhausts causing heat rejection plant to pull in hotter air... Increase Generator Flue Discharge Height Recirculation of air flow around dry air coolers and radiators... Raised Discharge Ducts on Dry Coolers Hotter air from around generator radiators being pulled towards Dry Coolers... Baffle between Generator Radiators and Dry Coolers

22 CASE STUDY 35 o C Peak Ambient Temperature and Max Wind Strength on that Day eng.com

23 CASE STUDY 35 o C Peak Ambient Temperature and Max Wind Strength on that Day Further Analysis:

24 CASE STUDY 35 o C Peak Ambient Temperature and Max Wind Strength on that Day Further Analysis:

25 CASE STUDY Key Issues: Traditional solutions haven t solved the problem... Still need to get more air into the roof compound... Still need better separation between intake and exhaust air flows Iterations later...

26 CASE STUDY Refined Design: Re-alignment of dry coolers Increased spacing between generator dry coolers Extended Exhaust Flues Gap under acoustic louvre behind parapet wall to reduce air flow resistance into plant compound were acoustic conditions can be relaxed. All Pipework at high level Full height acoustic screen where required Complete separation between supply and exhaust air flows through plant compound lid. Dry cooler discharge ducts removed and dry coolers raised to allow more air underneath.

27 CASE STUDY 35 o C Peak Ambient Temperature and Max Wind Strength on that Day Proposed Design:

28 CASE STUDY 35 o C Peak Ambient Temperature and Max Wind Strength on that Day Proposed Design:

29 CASE STUDY 35 o C Peak Ambient Temperature and Max Wind Strength on that Day Proposed Design: Dry Air Cooler & Generator Radiator Inflows:

30 CASE STUDY

31 WHY IS IT IMPORTANT High Temperature Incident Case Study: Indicative image only Inputs: Existing data centre at part load Roof mounted free cooling air cooled chillers Summers day 34 o C and peak 30kph wind speed Result: Peak temperature in roof compound of >50 o C due to wind condition increasing chiller re-circulation Multiple compressor trips Primary pumps on chillers with failed compressors still operating recirculating return water into primary Peak chilled water flow temperature of 28 o C Additional chillers manually brought online and the additional air flow requirement for the plant compound increasing recirculation Thermal runaway of chilled water system Failure of AHU DX and 37 o C Supply Air to Data Halls

32 CONCLUSION Manufacturers recommended space requirement is a GUIDELINE for access - It does not mean that the design will function as intended by default. Heat rejection plant tested in the factory under peak conditions will perform very differently when installed outside as part of an array of units under differing wind conditions. Peak wind conditions can have a much greater impact than peak temperature A warm windy day is usually worse than a hot still day. Recirculation can not only impact performance at peak ambient but will hinder free cooling availability. The plant compound is just as critical as the Data Hall to get right during the design phase - But is harder to achieve as you have no control on the environment! The case studies have demonstrated the benefits of using CFD outside of the white space and the importance it has in modelling plant compounds it can still go wrong if you are following manufactures guidelines and best practices alone. Using CFD You can model and predict the otherwise unpredictable why leave it to chance?

33 Alex Nock

COOKING THE ROOF CFD BEYOND THE WHITE SPACE

COOKING THE ROOF CFD BEYOND THE WHITE SPACE Alex Nock 20 November 2013 CONTENTS 1. Introduction» Introduction to RED» Modeling in Data Centres 1. What is CFD» How it works» CFD in Data Centres 3. Cooking