Technical Feasibility of Data Centre Heat Recovery in a Community Energy Network

Ryerson University

Mechanical and Industrial Engineering

Toronto, Canada

Adreon Murphy, MASc Candidate & Dr. Alan Fung, PhD., P.Eng

Presentation Overview

• Project Goal and Motivation• Data Centres and Community Energy• Methodology • Preliminary Concept• Energy Results• Bore Field Results• Limitations• Emissions Analysis• Conclusions• Future Work• Acknowledgements

Project Goal and Motivation

Goal:

• Determine how much energy can be shared between data centres and residential buildings

• Determine the GHG emission savings of a community energy system with energy sharing and ground source heat pumps

Motivation:

• Make the growing data centre industry more sustainable and open it up to a new revenue stream

Data Centre Cooling

• The cooling requirement of a data centre is equal to the electrical load of its equipment

• Data centres normally produce more heat than can be used in one building alone

• Typically, this excess heat is released to the atmosphere via cooling towers

Community or District Energy Networks

• Uses a network of pipes (below grade) to supply buildings with heating and cooling from a variety of energy sources

• Data Centres have been proven to be a economically viable energy low carbon energy source for these networks

Methodology

1. Collected hourly heating and cooling data from two data centres in Toronto and one residential building

2. Scaled data to represent a community and determined the portion of energy that is shared directly or sources from geo-exchange

3. Imported load profiles into Ground Loop Design to determine the COP of the ground source heat pump (GSHP) in heating and cooling mode

Preliminary Concept – Purely Energy Sharing

Preliminary Concept – Single Bore Field Winter Season

Preliminary Concept – Single Bore Field Summer Season

Results – Residential Building Heating30% capacity and 77% of energy provided by the community energy network

Results – Data Centre Cooling35% capacity and 61% of energy provided by the community energy network

Energy Results

Residential Heating

Portion of Energy

Data Centre Cooling

Portion of Energy

Residential Cooling

Portion of Energy

Existing Capacity 6,781 MWh 23% 13,582 MWh 39% 1,896 MWh 25%

Energy Provided by Geo-exchange

8,594 MWh 28% 6,978 MWh 19% 5,656 MWh 75%

Energy Sharing 14,593 MWh 49% 14,593 MWh 42% 0 0%

Total 29,968 MWh 100% 35,153 MWh 100% 7,552 MWh 100%

Bore Field LoadsAnnual Heating/Extraction Annual Cooling/Rejection

Energy Requirement 8,594 MWh 12,634 MWh

Energy After Dry Cooler Balancing 19,797 MWh 12,634 MWh

Seasonal COP of GSHP from GLD 3.1 7.1

Energy Extracted/Rejected to Ground 13,410 MWh 14,413 MWh

Bore Field Temperatures

Limitations of Model

• The GLD model does not consider different COPs for the ground source heat pump and the dry cooler

• The GLD model can only input one load side entering water temperature

– Using the typical residential building load side entering water temperature the cooling COP only changed by 2%

Emissions Analysis

Annual Residential Heating

Annual Data Centre Cooling

Annual Residential Cooling

Energy Requirement 29,968 MWh 35,153 MWh 7,552 MWh

Existing Emissions 6,593 tonnes 293 tonnes 84 tonnes

Remaining Unchanged 1,492 tonnes 113 tonnes 21 tonnes

Energy Sharing Emissions 174 tonnes 0 tonnes N/A

Dry Cooler Emissions 10 tonnes 8 tonnes

Geo-exchange Emissions 136 tonnes 47 tonnes 38 tonnes

Total GHG Savings 4,792 tonnes 123 tonnes 17 tonnes

Total GHG Savings 73% 42% 20%

Conclusions

• Energy sharing provided 49 and 42% of heating and cooling energy (14,593 MWh)

• 4.2 COP during energy sharing

• COP of GSHP 3.1 in heating mode and 7.2 in cooling mode

Future Work

• Optimize the portion of peak provided by the CEN and the number of buildings connected

• Create TRNSYS model to simulate the potential benefits of having one hot and one cold bore field

• Financial analysis to compare three scenarios and determine their viability

Acknowledgements

• Ontario Centre of Excellence

• Enwave Energy Corporation

• Faculty of Engineering, Architecture, and Science

(FEAS); Ryerson University

References

Alaica, A. A., & Dworkin, S. B. (2017). Characterizing the effect of an off-peak ground pre-cool control

strategy on hybrid ground source heat pump systems. Energy and Buildings, 46-59.

Brunschwiler, T., Smith, B., Ruetsche, E., & Michel, B. (2009). Toward zero-emission data centers through

direct reuse of thermal energy. IBM Journal of Research and Development, 53(3), 11:1 - 11:13.

Data Center Dynamics. (2015, March 18). DCD at CeBIT: Heat reuse worth more than PUE - Yandex.

(Data Center Dynamics) Retrieved April 27, 2017, from

http://www.datacenterdynamics.com/content-tracks/design-build/dcd-at-cebit-heat-reuse-worth-

more-than-pue-yandex/93586.fullarticle

Davies, G., Maidment, G., & Tozer, R. (2016). Using data centres for combined heating and cooling: An

investigation for London. Applied Thermal Engineering, 94, 269-304.

Ebrahimi, K., Jones, G. F., & Fleischer, A. S. (2014). A review of data center cooling technology, operating

conditions and the corresponding low-grade waste heat recovery opportunities. Renewable and

Sustainable Energy Reviews, 31, 622-638.

Government of Canada . (2016, April 19). Candadian Climate Normals 1981-2010 Station Data. Retrieved

Novemeber 9, 2016, from

http://climate.weather.gc.ca/climate_normals/results_1981_2010_e.html?searchType=stnName&txt

StationName=Toronto&searchMethod=contains&txtCentralLatMin=0&txtCentralLatSec=0&txtCentr

alLongMin=0&txtCentralLongSec=0&stnID=5051&dispBack=0

References

Government of Ontario. (2017). Ontario Building Code 2017.

Green Match . (2017, March 28). Condensing vs Non-Condensing Boilers. Retrieved April 27, 2017, from

Green Match: http://www.greenmatch.co.uk/blog/2015/10/condensing-vs-non-condensing-boilers

Hewlett-Packard. (2006, April 14). Model-Based Approach for Optimizing a Data Center Centralized

Cooling System. Retrieved October 29, 2016, from HP:

http://www.hpl.hp.com/techreports/2006/HPL-2006-67.pdf

IDEA Industry News. (2016, June 30). Update: In Seattle waste heat is being recovered to heat buildings.

(DistrictEnergy.org) Retrieved April 27, 2017, from

http://www.districtenergy.org/blog/2016/06/30/update-in-seattle-recovered-waste-heat-is-being-

used-to-heat-buildings/

References

Koomey, J. (2011). Growth in data center electricity use 2005 to 2010. New York Times.

LU-VE Sweden AB. (n.d.). AIACalc. Retrieved from http://www.aia.se/_en/Default.aspx?PagId=96

MathWorks Inc. (2013). MATLAB 2013. Retrieved from http://www.mathworks.com/

Natural Resources Canada . (2013, May 15). CO2 Emission Factors. Retrieved June 10, 2017, from

http://www.nrcan.gc.ca/energy/efficiency/industry/technical-info/benchmarking/canadian-steel-

industry/5193

Open District Heating . (2012). Bahnhof data centre Thule. Retrieved October 30, 2016, from

https://oppenfjarrvarme.fortum.se/?case=bahnhof_thule&lang=en

Open District Heating . (2017). Pilots . Retrieved from Open District Heating :

https://www.opendistrictheating.com/

Pacific Northwest Laboratory. (2014). ANSI/ASHRAE/IES Standard 90.1-2013 Determination of Energy

Savings: Quantitative Analysis. U.S. Department of Energy.

Thermal Dynamics. (2016). Ground Loop Design 2016. Retrieved from http://www.groundloopdesign.com/

Velkova, J. (2016). Data that warms: Waste heat, infrastructural convergence and the computation traffic

commodity. Big Data and Society , 1-10.

Appendix - Bore field design parameter summary

Working Fluid 12.9% Propylene Glycol

Design System Flowrate 3.0 GPM/ton

Ground Temperature 10°C

Ground Thermal Conductivity 2.94 W/mK

Ground Thermal Diffusivity 0.072 m2/day

Borehole Thermal Resistance 0.136 mK/W

Pipe Size 40mm

Borehole Diameter 108mm

Heat Pump Entering Water Temperature Condenser Side 38°C

Heat Pump Entering Water Temperature Evaporator Side 16°C

Appendix – Avoided Emissions and Emissions of CEN

Non-Condensing Natural Gas Boiler Efficiency 78% (Green Match , 2017)

Residential Chiller Plant COP 4.5 (Pacific Northwest Laboratory, 2014)

Data Centre Chiller Plant COP 6 (Hewlett-Packard, 2006)

Natural Gas Emission Factor 176g CO2e/kWh (Natural Resources Canada , 2013)

Ontario, Canada Electricity Grid Emission Factor 50g CO2e/kWh (Government of Ontario, 2017)

Energy Sharing COP (EWT: 16°C, EWT: 38°C) 4.2

Average Dry Cooler COP (1°C average air temperature) 31 (0.11kW/ton)