ASHRAE Journal - March 2015 - 65

2015 ASHRAE TECHNOLOGY AWARD CASE STUDIES

ABOVE Phase 1 secured customer entrance.
LEFT Arial view of entire Datacampus site.

This facility is designed for multi-tenant data center
use with a master plan involving multiple buildings and
phases of construction on a single site. Phase 1A and
1B have been occupied for over a year and consisted of
redeveloping a 110,000 ft2 (10 220 m2) building into data
center space, electrical infrastructure, and flex office
space, as well as a new 5,000 ft2 (470 m2) water-cooled
chiller plant building that was pre-assembled off site.
Phase 2 was recently completed and consisted of two
15,000 ft2 (1 400 m2) data center suites with associated electrical support infrastructure located within
an adjacent 292,000 ft2 (21 130 m2)building. Each
phase is designed to be stand-alone, but also crosstied through the chilled water system for increased
flexibility and redundancy.
The master plan includes a new chilled water plant
for each phase of construction. However, the chilled
water distribution supporting Phase 1 was cross-tied to
support Phase 2 due to available capacity of the Phase 1
plant. Future phases will also take advantage of remaining on-site chilled water capacity until the load requires
a new parallel chilled water plant to be installed.
The distribution piping is arranged in a 2N looped configuration with connection points and isolation valves in
place to allow new chilled water plants to be installed and
fully commissioned without affecting the live loads of the
existing data centers. The site is ultimately designed to
accommodate over 577,000 gross square feet (52 950 m2)
of space, including 270,000 ft2 (25 085 m2) of white space
supporting 31.9 MW of data center IT load.

Mechanical Design Overview
The mechanical system is designed to be concurrently
maintainable, modular, and scalable. Compared to
other similar size and type of systems it is also cost effective, energy efficient, and simple to operate.

TABLE 1 Breakdown of mechanical system energy use in each mode of operation. In

this application, the only variable affecting cooling load is the process load
and the only variable affecting efficiency, other than percent load, is ambient
wet-bulb. Excel was used for energy modeling.
KW/TON
FULL MECH.
COOLING

PARTIAL
ECONOMIZER

FULL
ECONOMIZER

0.037

0.019

CWP

0.061

0.070

0.061

0.438

0.243

0.000

PCHWP

0.020

0.000

SCHWP

0.029

0.038

CRAH Units

0.127

Makeup Air Unit

0.073

0.004

0.073

Total Cooling System

0.784

0.539

0.318

% Hours Annually

32%

61%

Annualized kW/ton

0.055

0.17

0.19

The heart of the mechanical system is the chilled water
plant. It consists of water-cooled centrifugal chillers with
open loop cooling towers for heat rejection and plate and
frame heat exchangers for series (integrated) waterside
economization. The distribution design uses primary-secondary chilled water pumping and thermal and condenser
water storage for thermal ride-through and back-up.
All of the equipment and associated piping is concurrently maintainable and installed in a modular and
redundant manner such that each "line-up" of capacity
equipment (chiller, cooling tower, heat exchanger, condenser water pump, and primary chilled water pump) is
repeatable and can be installed in 12 ft (3.7 m2) wide by
40 ft (12.2 m2) long shipping containers, or field erected
on site, depending on schedule and site constraints.
The modular design is extremely important for this
project because of the sheer size of the site and magnitude
MARCH 2015

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