Refrigerant Based Data Center Cooling Solution [email protected]

December 2012 1 COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.

Typical data center power consumption profile

Essentially, a PUE = ~2

Area of Interest

In addition to real savings to the environment, even modest advantages in cooling energy efficiency add up to significant savings in OPEX costs 2 COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.

Heat transport paths in a typical CRAC-cooled data/IP center From source (cabinet/frame/rack) to external environment: Waste heat

Issues created by CRAC-based cooling • CRAC units use a lot of energy, compared to the heat they remove. • Cool air mixes with warm air before entering the cabinet - increasing the air temperature used in cooling and decreasing its effectiveness. • Warm air mixes with cold air before returning to the CRAC unit – decreasing the efficiency of the CRAC unit. • Addressing “hot spots” or focused cooling is hard to achieve, leading to overcooling and poor utilization of space. 3 COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.

Active refrigerant based cooling solution - heat transport paths using pumped refrigerant from source to external environment: Pump unit transfers heat from refrigerant to building chilled water

Two-phase refrigerant is returned to the pump unit

Refrigerant supplied to the cooling units in a liquid state

Low maintenance – requires only periodic inspections

Cooling modules grow with your system

Building chilled water (XDP pump)

Low pressure (55 psi, 3.8 bar) pumped refrigerant supplied to each cabinet

Phase change occurs within micro-channel evaporators, removing heat from the server exhaust air

Use active, refrigerant-based heat exchangers to transfer heat into a coolant at the source of the heat and pipe to outside of local environment 4 COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.

Project Findings Applying Refrigerant Based Cooling to the target Data Centers Parameter

Data Center 1

Data Center 2

Data Center 3

Current Energy Consumption (MWh electricity / year)

5237.8

2871.8

7243,5

Energy consumption after the implementation of MCS

4097.0

2330.7

6211.1

Energy savings

1140.8

541.1

1023,4

Reduction primary energy consumption, GJp Electricity consumption / year (= x MWh Electricity year * 3,6 /0,4)

10267.2

4869.9

9210.6

456 ton CO2 / year electricity 445800 €

216.4 ton CO2 / year electricity 486411 €

409.4 ton CO2 / year electricity 733421 €

116000 €

27290 €

187130 €

Energy savings

115774 € / year

54651 € / year

103363 € / year

Current operation costs (Maintenance, increasing 3%/yr)

26200 € / year

24600 € / year

41000 € / year

Operation costs new technology (increasing 3%/yr)

8200 € / year

9100 € / year

13900 € / year

Reduction in operation costs

18000 € / year

15470 € / year

27100 € / year

15000 €

13345 €

15000 €

6.5%, 36517 €

6.5%, 39981 €

6.5%, 59836 €

Reduction CO2 emission, ton CO2 / year electricity (= x MWh Electricity year * 0,4) Investment costs Supplementary investment costs with respect to the standard installation

Subsidy - Via netbeheerder Subsidy: Verhoogde investeringsaftrek 5 COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.

Project Findings Applying Refrigerant Based Cooling to the target Data Centers Parameter Static payback time (exclusive subsidy)

Data Center 1

Data Center 2

Data Center 3

4.2 years

8.75 years

7.06 years

Static payback time (inclusive subsidy)

3.8 years

7.99 years

6,48 years

Dynamic payback time (exclusive subsidy) (Rent of 4%, increase in energy price 5% / yr, maint increase of 3%/yr)

5.4 years

6.77 years

6,47 years

Dynamic payback time (inclusive subsidy) (Rent of 4%, increase in energy price 5% / yr, maint increase of 3%/yr) Net present value (exclusive subsidy) (Rent of 4%, increase in energy price 5% / yr, maint increase of 3%/yr)

5.1 years

6.65 years

6,33 years

1.411.614 €

421.711 €

1.000.551 €

Net present value (inclusive subsidy) (Rent of 4%, increase in energy price 5% / yr, maint increase of 3%/yr)

1.461.150 €

472.900 €

1.072.468 €

Internal rate of return (no increase in energy prices, exclusive subsidy)

23,1 %

8,3 %

12 %

Internal rate of return (no increase in energy prices, inclusive subsidy)

25,8 %

9,8 %

13,6 %

Internal rate of return (increase in energy prices 5%/year, exclusive subsidy)

27,3 %

11,8 %

15,6 %

29,9 %

13,4%

17,2 %

Internal rate of return (increase in energy prices 5%/year, inclusive subsidy)

6 COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.

Project Findings, Summary Feasibility: A Refrigerant based cooling solution could be deployed at all of the sites proposed in the Project, as a retrofit replacing the existing air conditioned based cooling scheme. Practicality: Due to the cost of the Refrigerant Based Solution, and the Savings estimated, retrofitting to a refrigerant based design does not make practical sense.

7 COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.

Advice Considerations for a Refrigerant Based Cooling System • New deployment or retrofit • Designing a system with Refrigerant Based Cooling is ideal, but retrofitting an exisiting data center is possible. • Heat denisity – either per floor area (m2), or per cabinet • Higher heat densities are better accomdated by a refrigerant based system • Raised Floor • In a new site, if a raised floor is being considered for air distribution only, it can be avoided with a refrigerant based system • If the raised floor is used for cables, the height can be reduced • Chilled Water Plant water temperatue • The Chilled Water temperature will impact the refrigernat based cooling system operations. • If the chilled water plant is providing water at higher temperatures (above 7C), the capacity of the system suffers.

8 COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.

Advice Considerations for a Refrigerant Based Cooling System • “Free Air” Cooling, or “Air-Side” vs. “Water-Side” cooling techniques • If other cooling improvements are being considered, the impact on a refrigeant based cooling must be considered. • An Air-Side free air cooling system is generally not compatible with a refrigerant based system. Usually a free air scheme includes reducing or turining off chilled water during cooler months, and allowing cool air to circulate in the office. • Since the refrigerant based system requires the CW system, and usually means air movers have been removed, the two schemes are not compatible.

• A Water-Side scheme which allows for free air cooling of the chilled water is compatible with a refrigerant based system.

9 COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.

Advice Considerations for a Refrigerant Based Cooling System • Hot Aisle or Cold Aisle containment • Hot or Cold Aisle containment schemes are designed to eliminate mixing of the cold feed air and hot exhaust air in traditional air based cooling systems. •Hot Aisle containment closes off the rear of the cabinets and requires duct work to return the air to the cooling system. • Cold Air containment closes off the inlet to the cabinets, usually the front. • Both schemes require additional infrastructure and have their own issues. • Hot or Cold Aisle containmnet can be avoided with a refrigerant based cooling system.

10 COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.

Applications of the technology: Customer Success Stories US Wireless Carrier: The customer had a serious heat issue at their Mobile Switch Center (MSC) site in Texas, with aisle temperatures approaching 90◦ F. Additionally, their present heat densities were requiring that they spread out heat load leading to poor utilization of floor space. Finally they wanted to reduce the energy required for cooling. Solution: Refrigerant cooling systems were deployed in two separate locations in the office, addressing heating concerns in 57 cabinets (19 in a “data room”, 38 in the “telco room”). Results: Aisle temperatures were reduced from a high of 90◦F to between 67 and 72◦F. Two CRAC Units were turned off, and a third avoided. Based on the difference between the power consumed by the condenser model CRAC units and the condenser model refrigerant pumps added, this resulted in an estimated power reduction of 54% using the pumped refrigerant technology, which translates into a power savings of 75.7 KW and a yearly energy savings of about 663,400 KW hours, or $66,340 dollars based on 0.10 $/KW hr. 11 COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.

Applications of the technology: Customer Success Stories A US Wireless Carrier: Desired to design their new MSC sites with reduced floor space and increased heat per cabinet. The overall design could eventually grow to 150KW of heat per cabinet row (15 cabinets per row with 10KW each) with a potential of 12 rows of equipment per site. If successful, they planned to use this design in several (up to 8) locations in the US. Their analysis determined that traditional CRAC-based cooling would not be sufficient for the densities planned or the floor space that they wanted to dedicate to the new MSC sites. Additionally, they wanted to avoid a raised floor. Solution: The wireless carrier chose to use a chilled water solution in their new MSC design. Based on the heat load and densities planned, each row of 15 cabinets required a single chilled water refrigerant pump. Result: To date, four sites have been deployed with 4 pumps per site. Estimates for full site power reduction compared to a purely CRAC-based system (requiring 32 units) would be 97% using the pumped refrigerant technology. This translates into a power savings of 515KW and a yearly energy savings of about 4,500,000 KW hours, or $450,000 dollars based on 0.10 $/KW hr for a fully-populated site.

12 COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.

Applications of the technology: Customer Success Stories A US Satellite TV service provider: The customer planned for very high per cabinet heat loads, and determined that standard CRAC-based cooling would not be sufficient. Solution: The customer deployed two chilled water refrigerant systems in a redundant solution. 19 Heat exchangers were mounted in 10 cabinets. Result: The refrigerant cooling system provided adequate cooling for the dense heat loads in the office, and the redundant design provided for a robust cooling system. Although the customer did not consider a CRAC based system, an equivalent redundant, chilled water CRAC system would require 3 CRACS. This results in an estimated power reduction of 97% using the pumped refrigerant technology, which translates into an estimated power savings of 48.8KW and a yearly energy savings of about 427,400 KW hours, or $42,740 dollars based on 0.10 $/KW hr.

13 COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.

14 COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.