ASHRAE Journal - April 2015 - 75

2015 ASHRAE TECHNOLOGY AWARD CASE STUDIES

ABOVE SW1 reception office.
LEFT Complex Southwest One is a mixed real

estate project consisting of 662 units of residential rental housing, incorporating a commercial center and a medical center.

Complex Description
Built in the late 1960s, this pioneering
project offers its customers a diverse range
of accommodation including 103 townhouses and four residential towers of 10
floors each. Some roof terraces span buildings, and there is indoor and outdoor parking, as well as pools and beautifully landscaped areas. All facilities of the complex
are connected by a network of passages and
underground parking.
The domestic hot and cold water of the
complex is supplied via a centralized district
system, distributing water to all buildings
through centralized constant volume pumping stations. The complex is powered via a
single electric meter and a single gas meter.

TABLE 1 Projected financial highlights.
ENERGY SAVINGS

PROJECT
COST*

GRANTS

WATER
GAL/YR

YEARS

TON OF EQ.
CO 2

3,858 1.7 million 929,261 $594,000 $96,500

3.6

$/YR ELECTRICITY ELECTRICITY
KWH/YR
KW/YR

$139,634 1,908,262

GAS
FT 3 /YR

PAYBACK REDUCTION

* Cost related to energy efficiency measures
TABLE 2 Real annual energy consumption before and after the project.
ELECTRICITY

GAS

TOTAL
EKWH/YR

EKWH/FT 2 ·YR

July 2010 to $906,314 15,820,000 $52,967 3.8 million $959,281 16,960,500
June 2011

22.61

July 2012 to $869,071 14,241,257 $32,083 2.3 million $901,154 14,915,809
June 2013

19.89

$/YR

Savings

KWH/YR

$/YR

1,578,743

FT 3

/YR

$/YR

1.5 million

2,044,691

2.72

Electrical Savings
$96,303 (based on average cost of $0.061/kWh)
Gas Savings
$22,188 (based on average cost of $0.01/ft3)
Total Energy Savings $118,491

Domestic Water Network
Domestic hot water was distributed
through constant volume pumping stations
that pump the water from two underground
concrete tanks of 15,000 gallons (56 800 L) each to the
different facilities.
The domestic hot water network was an open system
where makeup water filled the concrete storage tanks.
The stored water was mainly heated via three atmospheric boilers of 1,000 MBH each and two electrical
heater tanks of 500 kW controlled via a power demand
control system. Both the control system and the boilers
exceeded their useful average life. Because of heat dissipation through the concrete tanks, water temperature
couldn't be maintained at 140°F (60°C) during winter.
In addition to heat dissipation across the concrete tanks,
hot water recirculation was oversized causing additional
heat loss. SW1 was looking into a major retrofit to its

domestic water network to renew the main mechanical
system, ensure code compliance, and reduce the energy
cost related to domestic water heating. The daily domestic hot water consumption of the complex was measured
to 26,500 gallons (100 313 L) in a typical day.

Radiology Clinic
In 2011, SW1 was looking to integrate a new radiology
clinic within its medical center. The new clinic was intended
to include an MRI section and some medical offices along
with the seating and common areas of a clinic. The design
of the new clinic was carried out with high energy efficiency
and sustainable development standards including efficient
envelope, mechanical and electrical systems.
One of the major challenges that the design team
faced was to reduce the impact of the implementation
of the new clinic on the residential complex during
and post construction. Medical spaces necessitate
APRI L 2015

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