article hosptial upgrade
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8/12/2019 ARTICLE Hosptial Upgrade
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SECOND PLACE: HEALTH CARE FACILITIES. EXISTING
Heat Recovery Geothermal Save Energy
UPGR DEy Jack Kafesdjian Eng. Member ASHRAE
Montreal's Louis-H. Lafontaine Hospital is a 140-year
old psychiatric hospital that at its peak housed as
many as 5,000 patients. Historic buildings of this type offer
many opportunities for energy savings. Designers identified 26
energy-saving measures for the 1 5 million ft 2 ( 139 355 m2)
hospital, and the hospital administration selected 1 8 based on Montreal's Louis-H Lafontaine Hospital reduced energy con
sumption by 15 , with a projected yearly decrease of 2,387
available funds (see Energy Saving Measures sidebar).
The initial energy efficiency study performed in 2005- 06,
revealed that the annual energy consumption for the hospi
tal in the previous year was approximately 64 million kWh
(230 400 GJ) or 44 kWh/ft2 (473 kWh/m2) at 0.04/kWh
( 11.11/GJ). This equated to roughly 2.4 million in annual
energy costs (in 2003 04 dollars) and was split between
three energy sources: natural gas (70%); electricity (18%)
and fuel oil (12%).
The study showed that the annual energy savings potential
was roughly 850,000. The construction costs were estimated
at 6 million, and the original project payback period was
seven years (maximum allowable for government funding).
The financial savings estimated for this project are based on
the following utility rate structure (from 2006):
• Electric demand: 12.60/kW;
• Electric consumption: 0.0256/kWh;• Natural gas: 0.40fm3 ( 0.01 /ft3); and
• Fuel oil No.2: 0.41/L ( 1.55/gallon).
44 ASHRAE Journal
tons of greenhouse gas emissions.
The first 29 months of operation beginning in November
2006 and ending in March 2009 generated a substantial reduc
tion of more than 1.5 million or 20.8 million kWh (74 850
GJ) in energy consumption. The period from March 2009 to
March 2010 generated a reduction of 800,000 or 9,335,000
kWh (33 600 GJ) , which is closely aligned to the predicted
annual savings.This represents a 14 .6% reduction ofthe total
energy consumption for the hospital.
The energy reduction is mainly achieved using boiler stack
heat recovery and geothermal energy to heat domestic hot wa
ter. It does not include ventilation and air-conditioning ~ v i n g sbecause a large portion of the hospital has neither system. Large
portions of the hospital were not evaluated due to upcoming
renovation projects to address the lack of adequate ventilation.
bout the uthor
Jack Kafesdjian, Eng., is the techn ica l director at EnerCible, a department of
SNC-Lava lin s TIB division in Montrea l.
ashrae.org August 2011
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he 140-year-old hospital housed approximately 5,000 patients at its peak.
The most innovative and important
measure ofthis project is using the exist
ing 100,000 gallon (378 541 L) storage
tank that had once stored non-potable
water for fire suppression purposes.
In the winter, the tank now stores high
temperature domestic hot water at 180°F
82 °C) that is produced by the latent heat
reclaim unit installed on the boiler stacks.
The latent heat reclaim system con
sists simply of a stainless steel indirect
type heat exchanger in which the watercirculates and is heated via the flue gases.
The quantity of flue gas drawn from the
main chimney is controlled by the vari
able speed fan and set according to the
desired water output temperature.
The annual city water consumption
used for domestic hot water and boiler
makeup water was high. This motivated
the hospital administration to enhance
the efficiency of the unit to the maximum
since it fully condenses the flue gases
when below 130°F (54°C), which oc
curs during most of the operating time.
The lowest chimney exhaust temperature
recorded was 70°F 21 °C). This is a huge
gain from the traditional 550°F (288°C)
flue gas temperature seen in the past.
This energy (about 15 ) was formerly
lost because of the lack of a heat reclaim
system. Currently, it is being used to
preheat the boiler feed water and also
to entirely heat the domestic hot water
consumption of the hospital, which wasevaluated at 70,000 gallons (264 979 L)
per day in the winter.
Each of the two boiler feed water
pumps, which operated in the past at
constant flow, also has been replaced with
four multistage variable speed pumps that
now operate according to the actual boiler
steam load.
The existing boiler combustion makeup
air unit (12 ,500 cfm (5899 Lis]), which
consisted of an indirect-fired gas burner,
was modified to insert a glycol coil. The
heat from the new domestic water loop at
180°F (82°C) was used via a heat exchanger to preheat the incoming combustion air
instead of using natural gas during most
of he winter. This same strategy was used
for the laundry room HVAC unit (30 ,000
cfm [14 158 Lis] of 100 fresh air) that
was preheated and heated by two separate
steam coils in the past.
During the summer, the closed-loop
geothermal heat pump system of 150
tons (528 kW) of capacity combined
with 36 vertical wells of 500ft 152m)
of depth or a total of 18 ,000 linear ft
(5486 linear m), produce the domestic
hot water requirements. In addition, it is
only operated during off-peak periods to
optimize the electric use factor.
Since the heat pumps can only produce
a maximum water temperature of 120°F
(49°C), the new 1 MW off-peak electric
steam boiler increases the domestic hot
water temperature to 145°F (63°C) via a
heat exchanger. The water is then stored
in the reservoir.The warehouse of the hospital was
heated in the winter by several suspended
nergy Saving Measures
Storage of high temperature
domestic hot water in a 100,000
gallon 378 541 L tank
Production of domestic hot water via
an off-peak geothermal system of
150 tons 528 kW) of capacity and
18,000 linear ft 5486 linear m) of
vertical wells
Sensible and latent heat reclaim
from the chimney stacks to preheat
boiler feed water and domestic hot
waterProduction of domestic hot water
via an off-peak 1 MW electric steam
boiler
Variable speed multistage boiler
feed water pumps
Direct digital controls replacing old
pneumatic controls
Micro-modulation of natural gas and
fuel oil burners for high pressuresteam boilers 950 bhp [708 kW]
total capacity)Building envelope improvements
(sealing of more than 4 ,300
windows or 150,000 line\]r ft or 28
miles [45 720 linear m or 45 km])
Lighting retrofit of 3,100 fixtures
from T12 fluorescent lamps and
magnetic ballasts to high-efficiency
T8 fluorescent lamps and electronic
ballasts
High pressure steam piping thermal
insulation of 9 ,000 line ar ft 2743
linear m)
steam unit heaters but also contained
five cold rooms to preserve the frozen
and refrigerated foods. These cooling
units were connected to a common cool
ing tower that would then exhaust the
condenser-side energy to the environment
throughout the year, instead of reusing
it in the winter. Another measure wasthe addition of two water-to-water heat
pumps of 7.5 tons (26 kW) of capacity
SHR E ournal 45
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Geothermal well digging equipment dug 6 vertical wells to produce domestic hot water
each in series with the condenser side
circuit going to the cooling tower to heat
the space, instead of using steam, and
reuse this otherwise lost energy.
The modifications performed to the
building envelope greatly reduced
the heating energy requirements and
also improved the comfort conditionsfor the entire hospital's population in
winter. More than 4,300 windows or
the equivalent of 150,000 linear ft (45
720 linear m) or 28 miles ( 45 km) in
length, were sealed to reduce the heat
loss in the winter and reduce cold air
draft problems. Each winter patients,
doctors and sta ff raised concerns about
these problems to the hospital s ad
ministration department over the past
several years.
Practically no HVAC-related me
chanical improvement measures were
implemented in this energy-efficiency
project because of the minimal amount
of existing space and air conditioning
equipment in the hospital. Eighty-five
percent of the spaces are handled by
natural ventilation in conjunction with
several original exhaust fans , which
was the original design used to provide
the minimal air changes required. Also,
these same spaces are mainly heated
by steam radiators in winter. Future
building improvement and renovation
46 ASHRAE Journal
projects also include adding further
space conditioning to improve the en
vironment where patients, doctors and
personnel reside.
One building's perimeter that was
originally heated by a constant high tem
perature hot water loop provided from
a steam/hot water heat exchanger, wasimproved by implementing an indoor
outdoor temperature control strategy.
Previously, the only way to adequately
control room temperature (generally
higher on the south facing side because
of additional sun load) was to open
windows when it was too hot in the
room. This was common practice even
when the outdoor temperature was well
below freezing.
In addition, the existing pneumatic
controls for the heating were upgradedwith state-of-the-art direct digital con
trols to improve energy efficiency, com
fort conditions and to reduce energy,
regular maintenance and major repair
expenditures as well.
Bi-metallic room thermostats used for
the electric baseboards in the Fernand
Seguin Research building (an adjacent
and more recent construction from 1991)
were also replaced by electronic and pro
grammable models to control the room
temperature more accurately and also
implement a night-setback strategy.
ashrae .org
uilding t a Glance
Name: Louis-H. LaFontaine Hospital
Location: Montreal
Owner: Provincial Government of
Quebec
Principal Use: Hospital
Includes: Admin istrative offices,
cafeteria , warehouse, laundry
facilities, research center
Employees/ Occupants : 120/ 1 ,200
Gross Square Footage: 1.5 million
Conditioned Space: 22 5 ,000
Substantial Completion/ Occupancy:
Retrofit completed in 2006
This project also received substantial
grants from both local energy providers,
Gaz Metro and Hydro-Quebec. The total
amount attributed to the hospital was
$185 ,000 ($108,000 by Gaz Metro and
$77,000 by Hydro-Quebec).The hospital administration under
stood from the beginning of this project
that to decrease the annual operational
expenditures and energy consumption
for the hospital, new heat reclaim and
more efficient equipment were neces
sary. Because of the minimal operations
staff and personnel available on-site,
the equipment for this project was
selected with special care so that ad
ditional staff will not be required in
the future.The geothermal system and new elec
tric steam boiler are solely run during off
peak hours, permitting the more efficient
use of electric energy and eliminating
the need to construct further dams and
hydroelectricity generating plants to
supply the ever increasing electric energy
demand and use.
The 15% reduction of energy consump
tion will generate a yearly decrease in the
production of 2,387 tons of greenhouse
gas (GHG) emissions or the equivalent
of 682 cars.•
August 2011
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