ASHRAE IRELAND HVAC FOR DATA...
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Michael Geraghty Building Services Engineer (DipEng) Company owner and managing director [email protected] ASHRAE IRELAND HVAC FOR DATA CENTRES
Transcript of ASHRAE IRELAND HVAC FOR DATA...
Michael GeraghtyBuilding Services Engineer (DipEng)
Company owner and managing director
ASHRAE IRELANDHVAC FOR DATA CENTRES
OVERVIEW OF THE MARKET SITUATION IN IRELAND
Relative Data Centre Scale
Forty-six operational data centres in Ireland in Q1 2018
Ireland Hosts Commercial Data Centres of all Sizes
1 MW to 10 MW<1 MW 10 MW to 20 MW
812161020 MW to 40 MW
Source: www.bitpower.ie
Source: www.bitpower.ie
Source: www.bitpower.ie
Source: www.bitpower.ie
Sustainability Measures
Source: www.bitpower.ie
Source: www.bitpower.ie
Source: MMCD
Source: MMCD
Source: MMCD
HYPERSCALEFacebook, Google, Amazon, Microsoft, Apple
These companies build to their own specification
MULTI-TENANT COLOCATIONEdgeConnex, K2, Keppel.
These companies use private investor funds.
The data centres are built to suit the clients needs.
The hyperscale data companies lease “white space”.
COLOCATION WHOLESALE
Digital Realty, Equinix, InterXion.
These facilities are designed for partial use by clients that lease ‘white space’.
PRIVATE
BT, Eir, OPW.
These are mostly for Financial companies, banks, telecom and I.T. companies
EDGE DATA CENTRES
Not yet in Ireland.Edge DC’s will range from 500kW to 1 MW.They will be located closer to where the end user is, to help improve speed and latency
DATA CENTRES ARE NOT BUILT IN IRELAND BECAUSE OF THE
WEATHER
Companies come to Ireland because:The others are hereThere is a critical mass here – designers, contractors, i.T. companiesWe have suitable infrastructure (ecosystem)Because they are US companies
Chance of interruption is lowSeismic activityWarExtreme weather
Tax is more or less the same everywhere for large companies
TERMINOLOGY
Power Usage Effectiveness
A lot of air is required
Q=mcΔt
1000kW = m x 1.2 x 1.02 x 10K
1000kW/ 12.24 = m
81.69m3/s = m
DESIGN ISSUES
https://www.iesve.com/case_studies/images/cbo-data-centre/hall.jpg
FRESH AIR DAMPERSCONDENSATION RISK
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There is a risk of condensation on the internal surface of fresh air intake dampers when they are closed.
This is a function of the indoor air condition, the outdoor temperature and the conductivity of the damper material
FRESH AIR DAMPERSCONDENSATION RISK
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Frame Entropic Halton UTT Alternate solution
Material Stainless steel, AISI 304 Aluminium
Density (kg/m3) 8000 2700
Heat capacity (J/kg*K) 500 897
Heat conductivity(W/m*K)
16.2 205
Outdoor temp (K) 263.15 263.15
Surface area (mm2) 890 506
Indoor temp 283.15 283.15
Heat flux* (W/m2) 0.1 10
Total heat loss (W) 0.089*10-3 5.06*10-3
FRESH AIR DAMPERSICE RISK
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In cold conditions, there is a risk of ice forming on the internal surface of fresh air intake dampers when they are closed. This is a function of the indoor air condition, the outdoor temperature and the conductivity of the damper material
https://www.iesve.com/case_studies/images/cbo-data-centre/hall.jpg
FRESH AIR DAMPERSCORROSION RISK
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In costal regions, there is a risk of corrosion of the metals in the dampers.
This is mainly caused by corrosive salty outdoor air coming in contact with the metal surfaces of the fresh intake dampers
http://www.iesve.com/case_studies/images/cbo-data-centre/hall-y-03.jpg
FRESH AIR INLETSFree cooling
CFD Analysis of mixing box
Characteristics of inlet dampers and filters on full recirc.Air tightnessRisk of condensationPressure dropRisk of corrosion
stainless steel vs AluReliability
delivery phasein usemaintenance
Mechanisms, linkages, actuators, bearings.
Full scale mock-ups of HVAC systems
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CFD Analysis for a hyperscale Data Centre
HOT AIR RISES
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CFD Analysis a large Data Centre
GOOGLE SHIFTS TO LIQUID COOLING FOR AI DATA CRUNCHING
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An eight-rack pod of Google's liquid-cooled TPU version 3 servers for artificial intelligence workloads. (Image: Google)
VOLUME AND PRESSURE DROP
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2.4m
2.4m
VOLUME AND PRESSURE DROP
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Panel filters• Cheap• Effective• Widely available• Pressure drop 50Pa
Electrostatic filters
• Removes pollen, bacteria and dust• Reliable and simple• Very low energy use• Extremely low maintenance costs, it
never needs replacing• It can be washed and sanitised using
ordinary detergents, without any decline in efficiency or product life
• No ongoing costs, no replacement filters required
• Integrated ‘Change filter’ alarm• Pressure drop 10Pa
• 1000kW = 86m3/s
AHU DESIGN FOR CRAC SYSTEMSWith CRAC units in the space, the fresh air needs to be conditioned.
Normal Summer processReturn 5080m3/h34C & 27.18% (9g/kg)
Fresh air m3/h40C & 30% R.H (13.88g/kg)
Dump 496-0m3/h
5730m3/hCooling 50kWOff coil =13C & 97% (9g/kg)
Mixed air with 20% FA 5730m3/h35.21C & 28.13%(9.98g/kg)
5730m3/hHeating 17kWOff coil = 22C & 9g/kg
Project: Subject: Summer mode - Analysis of air as it flows through the AHUDate: 20-02-2017Author: Mark Mc Dougall, Entropic
20-100% Fresh Air 1146-5730m3/hr
80-0% Recirc 4584-0m3/h
Humidifier offSupply Air 5730m3/h22C & 54.7% (9g/kg)
Fresh air 5730m3/h40C & 30%(13.88g/kg)
5730m3/hCooling 74kWOff coil =13C & 97% (9g/kg)
5730m3/hHeating 17kWOff coil = 22C & 9g/kg
Reliable, energy efficient and low environmental impact systems
Free cooling
DescriptionAmbient Air is used to directly cool the data hall. Return Air is drawn from the Hot Aisle with a fan wall. Desired supply air temperature is controlled with a mixing box between the ambient and return air. Mix air is filtered and supplied to the Data Hall with a fan wall. Non-recirculated air is dumpedIf additional cooling is required this can be a adiabatic cooler, DX or CHW coilAdvantagesNo Additional cooling is required provided the ambient air is lower than the cold aisle (Eg 27C cold aisle in Ireland). So no water usage or water treatment is required.No additional fresh air for pressurisation / ventilation
ConsiderationsAmbient air needs to be of suitable quality for supply to the Data Hall eg maritime climate or very polluted city or industrial areaSupply and return fan wall will run the same airflow in parallel which may (depending onArchitecturally challenging
Reliable, energy efficient and low environmental impact systems
Free cooling
Indirect air cooled – plate heat exchanger methodFull recirculation air handling unit(s) with an air to air plate heat exchanger. Cooling is achieved by passing fresh air over the plate in a cross flow pattern to dump.
AdvantagesLeast expensive of air side heat recovery Only one circulation fan on room side
ConsiderationsConnections are difficult requiring cross over of flows and returnsWill need additional cooling from approx 20CHX will need to come in short sections to come out from the side of the unit
Reliable, energy efficient and low environmental impact systems
Free cooling
Double plate heat exchanger.
Full recirculation air handling units with 2no air to air plate heat exchangers in series. Cooling is achieved by passing fresh air over the 2no plate HXs in a cross flow pattern to dump.
AdvantagesMore efficient heat exchange than a single HXLower hours of supplementary cooling required
Supply & return connections on same side
ConsiderationsHigher cost than a single exchangerHigher pressure drop than a single HX unitHXs will need to come in short sections to come out from the side of the unitWill need additional cooling from approx 23COnly one circulation fan on room side
Reliable, energy efficient and low environmental impact systems
Free cooling
Vertical Rotary Wheel Heat ExchangerSeries of full recirculation air handling units with a rotary heat recovery wheel mounted in the AHU. Cooling is achieved by passing fresh air through the rotating wheel cooling the recirculated air as passes to dump
Full recirculation air handling units with 2no air to air plate heat exchangers in series. Cooling is achieved by passing fresh air over the 2no plate HXs in a cross flow pattern to dump.
AdvantagesMore efficient heat exchange than a single HXLower hours of supplementary cooling required
Supply & return connections on same side
ConsiderationsHigher cost than a single exchangerHigher pressure drop than a single HX unitHXs will need to come in short sections to come out from the side of the unitWill need additional cooling from approx 23COnly one circulation fan on room side
Build healthier buildingsReduce pollutants and chemicalsReduce green house gas emissionsReduce the use of HFCs in buildings.
ENVIRONMENTAL MISSION
Article 9(1) of the Directive requires Member States to ensurethat:-- by 31 December 2020, all new buildings are nearly zeroenergy buildings; and- after 31 December 2018, new buildings occupied andowned by public authorities1 are nearly zero-energybuildings.
http://www.greenpeace.org/international/Global/international/planet-2/report/2009/5/HFCs-Fgases.pdf
CIBSE Guide B (2005)
Half Airflow
>80% Reduction
on electricity use
ENERGY EFFICIENCY
HFC GWP
At least 3000times worse than CO2
ACCIDENTS HAPPEN, REFRIGERANTS LEAK
High efficiency air intake external weather louvres with corrosion protection
Main featuresWater separation
Corrosion resistance
Reference project
PRESENTATION ON USB
