ASHRAE IRELAND HVAC FOR DATA CENTRES Michael Geraghty Building Services Engineer (DipEng) Company owner and managing director michael@entropic.ie
OVERVIEW OF THE MARKET SITUATION IN IRELAND
Relative Data Centre Scale Ireland Hosts Commercial Data Centres of all Sizes Forty-six operational data centres in Ireland in Q1 2018 <1 MW 1 MW to 10 MW 10 MW to 20 MW 10 16 12 20 MW to 40 MW 8 Source: www.bitpower.ie
Source: www.bitpower.ie
Source: www.bitpower.ie
Source: www.bitpower.ie
Source: www.bitpower.ie Sustainability Measures
Source: www.bitpower.ie
Source: MMCD
Source: MMCD
Source: MMCD
HYPERSCALE Facebook, Google, Amazon, Microsoft, Apple These companies build to their own specification
MULTI-TENANT COLOCATION EdgeConnex, 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 here There is a critical mass here designers, contractors, i.t. companies We have suitable infrastructure (ecosystem) Because they are US companies Chance of interruption is low Seismic activity War Extreme weather Tax is more or less the same everywhere for large companies
TERMINOLOGY Power Usage Effectiveness
DESIGN ISSUES 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 https://www.iesve.com/case_studies/images/cbo-data-centre/hall.jpg
FRESH AIR DAMPERS CONDENSATION RISK 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 21
FRESH AIR DAMPERS CONDENSATION RISK Frame Entropic Halton UTT Alternate solution Material Stainless steel, AISI 304 Aluminium Density (kg/m 3 ) 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 (mm 2 ) 890 506 Indoor temp 283.15 283.15 Heat flux* (W/m 2 ) 0.1 10 Total heat loss (W) 0.089*10-3 5.06*10-3 22
FRESH AIR DAMPERS ICE RISK 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 23
FRESH AIR DAMPERS CORROSION RISK 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 24
FRESH AIR INLETS Free cooling CFD Analysis of mixing box Characteristics of inlet dampers and filters on full recirc. Air tightness Risk of condensation Pressure drop Risk of corrosion stainless steel vs Alu Reliability delivery phase in use maintenance Mechanisms, linkages, actuators, bearings. CFD Analysis for a hyperscale Data Centre Full scale mock-ups of HVAC systems 25
HOT AIR RISES CFD Analysis a large Data Centre 26
GOOGLE SHIFTS TO LIQUID COOLING FOR AI DATA CRUNCHING An eight-rack pod of Google's liquid-cooled TPU version 3 servers for artificial intelligence workloads. (Image: Google) 27
2.4m VOLUME AND PRESSURE DROP 2.4m 28
VOLUME AND PRESSURE DROP 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 29
AHU DESIGN FOR CRAC SYSTEMS With CRAC units in the space, the fresh air needs to be conditioned.
Return 5080m3/h 34C & 27.18% (9g/kg) Normal Summer process 80-0% Recirc 4584-0m3/h Dump 496-0m3/h Project: Subject: Summer mode - Analysis of air as it flows through the AHU Date: 20-02-2017 Author: Mark Mc Dougall, Entropic 20-100% Fresh Air 1146-5730m3/hr Fresh air m3/h 40C & 30% R.H (13.88g/kg) Supply Air 5730m3/h 22C & 54.7% (9g/kg) Humidifier off 5730m3/h Heating 17kW Off coil = 22C & 9g/kg 5730m3/h Cooling 50kW Off coil =13C & 97% (9g/kg) Mixed air with 20% FA 5730m3/h 35.21C & 28.13% (9.98g/kg) 5730m3/h Heating 17kW Off coil = 22C & 9g/kg 5730m3/h Cooling 74kW Off coil =13C & 97% (9g/kg) Fresh air 5730m3/h 40C & 30% (13.88g/kg)
Reliable, energy efficient and low environmental impact systems Free cooling Description Ambient 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 dumped If additional cooling is required this can be a adiabatic cooler, DX or CHW coil Advantages No 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 Considerations Ambient air needs to be of suitable quality for supply to the Data Hall eg maritime climate or very polluted city or industrial area Supply and return fan wall will run the same airflow in parallel which may (depending on Architecturally challenging
Reliable, energy efficient and low environmental impact systems Free cooling Indirect air cooled plate heat exchanger method Full 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. Advantages Least expensive of air side heat recovery Only one circulation fan on room side Considerations Connections are difficult requiring cross over of flows and returns Will need additional cooling from approx 20C HX 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. Advantages More efficient heat exchange than a single HX Lower hours of supplementary cooling required Supply & return connections on same side Considerations Higher cost than a single exchanger Higher pressure drop than a single HX unit HXs will need to come in short sections to come out from the side of the unit Will need additional cooling from approx 23C Only one circulation fan on room side
Reliable, energy efficient and low environmental impact systems Free cooling Vertical Rotary Wheel Heat Exchanger Series 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. Advantages More efficient heat exchange than a single HX Lower hours of supplementary cooling required Supply & return connections on same side Considerations Higher cost than a single exchanger Higher pressure drop than a single HX unit HXs will need to come in short sections to come out from the side of the unit Will need additional cooling from approx 23C Only one circulation fan on room side
ENVIRONMENTAL MISSION Build healthier buildings Reduce pollutants and chemicals Reduce green house gas emissions Reduce the use of HFCs in buildings.
Article 9(1) of the Directive requires Member States to ensure that:- - by 31 December 2020, all new buildings are nearly zeroenergy buildings; and - after 31 December 2018, new buildings occupied and owned by public authorities1 are nearly zero-energy buildings.
http://www.greenpeace.org/international/global/international/p lanet-2/report/2009/5/hfcs-fgases.pdf
CIBSE Guide B (2005)
Half Airflow >80% Reduction on electricity use ENERGY EFFICIENCY
HFC GWP At least 3000 times worse than CO 2
ACCIDENTS HAPPEN, REFRIGERANTS LEAK
Reference project High efficiency air intake external weather louvres with corrosion protection Main features Water separation Corrosion resistance
PRESENTATION ON USB
Thank you michael@entropic.ie