November 23, 2018 TBTE Ref. No. 18-340-2, Rev. 0
HVAC STUDY
Manitouwadge Community Centre
23 Manitou Road, Manitouwadge, ON
TBTE Project Number: 18-340-2
Prepared For:
Township of Manitouwadge 1 Mississauga Drive
Manitouwadge, ON
P0T 2C0
Prepared By:
TBT Engineering Ltd. 1918 Yonge Street
Thunder Bay, Ontario
P7E 6T9
Manitouwadge Community Centre– HVAC Study TBTE Ref No.: 18-340-2 Rev. 0
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Table of Contents
1.0 INTRODUCTION ................................................................................................................ 1
2.0 BACKGROUND ................................................................................................................. 1
3.0 EXISTING CONDITIONS ....................................................................................................... 2
3.1 ICE PLANT ROOM .................................................................................................................. 2
3.2 ARENA ................................................................................................................................ 3
4.0 UPGRADE OPTIONS .......................................................................................................... 4
4.1 ICE PLANT MACHINE ROOM EXHAUST ....................................................................................... 4
4.1.1 OPTION 1 – NEW SUPPLY AND EXHAUST FANS ............................................................................... 4
4.1.2 OPTION 2 – HEAT RECOVERY VENTILATOR ..................................................................................... 6
4.2 ARENA DEHUMIDIFICATION ..................................................................................................... 7
4.2.1 OPTION 1 – NEW MECHANICAL DEHUMIDIFIER UNITS ..................................................................... 8
4.2.2 OPTION 2 – DESICCANT WHEEL DEHUMIDIFICATION UNIT ............................................................... 9
4.3 ENERGY AUDIT .................................................................................................................... 10
5.0 COST ESTIMATES ............................................................................................................ 11
6.0 CONCLUSION ................................................................................................................ 12
7.0 CLOSURE ...................................................................................................................... 12
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1.0 INTRODUCTION
TBT Engineering Limited (TBTE) was retained by the Township of Manitouwadge to provide a heating,
ventilation and air conditioning (HVAC) Study for the Basement Ice Plant Room and the main Rink Area
within the Manitouwadge Community Centre located at 23 Manitou Road in Manitouwadge, ON.
The purpose of the Study is to establish a baseline understanding of the existing ventilation systems in
the aforementioned building, focusing namely on code compliance, operational costs, functionality and
feasibility of proposed upgrades.
Miscellaneous deficiencies noted on site are also included in the body of the Study. Estimated capital
costs associated with proposed options/upgrades will also be included.
2.0 BACKGROUND
The Manitouwadge Community Centre is
located in the central portion of Manitouwadge,
Ontario, adjacent to the town’s roundabout.
The facility contains a hockey arena, fitness
facility, gymnasium, curling rink, library and
various interior programming spaces. There are
two pools located outside on the southwest side
of the property. A baseball diamond and various
support structures are located on the southeast
side of the property.
The facility was originally constructed in 1964 and has undergone major renovations in 1972, 1976,
1993, 1998, 2001 and 2007 as well as an addition to the Arena in 1992. The facility occupies an overall
gross footprint area of approximately 53,750 ft2 and has three sections: an Arena, central support area
and southwest wing. The central and southwest portions of the facility have a basement.
Figure 2.1 - Manitouwadge Community Centre
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3.0 EXISTING CONDITIONS
3.1 ICE PLANT ROOM
All refrigeration equipment serving the
Community Centre is located within the 750 ft2
Ice Plant Machine Room, located on the central
Basement Level (Figure 3.1). The ice plant
equipment serves both hockey and curling rinks.
There are two 50 HP compressors, two brine
chillers, a holding tank, two brine circulating
pumps (10 HP and 20 HP) and an outdoor
evaporative air-cooled condenser on the roof.
CIMCO Refrigeration overhauled the plant in
2003 with all new equipment. All major
equipment in the room uses 575/3/60 power.
Since the refrigerant used in the system is
ammonia, an ammonia gas detector was
installed as per code requirements with a
digital control panel outside the room. The gas
detection system was installed in 2017.
The existing exhaust fan is a wall-mounted,
direct-driven propeller type which remains
from 1964 (Figure 3.2). Its 1/4 HP, 115/1/60
motor was replaced in 2014. The fan is
controlled with a local switch. Based on motor and fan size, the fan’s capacity is estimated to be
approximately 2,000 CFM. Exhaust air from the fan is ducted to roof level and discharged near the
rooftop-mounted evaporative condensing unit.
Make-up air for the exhaust fan is provided passively to the space through a large gravity damper
located above the entrance door. However, since the fan is not powerful enough to force it open, it has
been manually propped open and acts as an open grille. Air is drawn in from the corridor space.
Figure 3.2 – Machine Room Exhaust Fan
Figure 3.1 – Ice Plant Machine Room
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3.2 ARENA
The Arena portion of the Community Centre
(Figure 3.3) contains the hockey rink as well as
concrete bleachers, an Announcer Booth,
Change Rooms, Washrooms, and rink support
spaces such as the Zamboni Room and second
level Mechanical Room. All support spaces were
added as an addition to the Arena in 1993.
Ice is kept in the Arena throughout the fall and
winter for hockey/skating activities and is
removed in the spring. When there is no ice in summer months, the concrete floor is used for various
indoor activities such as volleyball, badminton, road hockey, shuffleboard and tennis.
The roof of the Arena is not insulated and has been problematic over the years. Frequent issues include
detachment of exterior adhered roofing membrane due to wind, and formation of condensation inside
the Arena during ice season. The lack of a roofing membrane promotes excessive infiltration and water
ingress while lack of insulation promotes formation of condensation on interior surfaces. Condensation
forms on piping, wooden structural members and lights. Condensation then falls on the ice surface,
causing roughness and discolouration. In a separate TBTE Study, a roof replacement is recommended
which will significantly reduce (but not eliminate) infiltration and condensation rates.
The Arena is currently ventilated by a single, small exhaust fan located on the southeast wall. The wall-
mounted fan is ducted into the second level Mechanical Room, where another wall opening allows air to
exit the building. The exhaust fan remains from the original construction of the Arena addition in 1993
and is manually operated by rink staff when the Zamboni is used.
Several direct-fired, propane radiant heaters are mounted above the bleachers and player benches. The
heaters are connected to local thermostats and are activated by an electronic gas valve upon a call for
heat. The heaters appear to have been installed within the past 15 years. It should be noted that the
heaters are not vented to the outdoors. Once burned, propane exhaust gases contain carbon monoxide
and nitrogen dioxide by-products. Though not part of the scope of this Study, it is important to note that
the lack of proper venting poses a health hazard to occupants.
Figure 3.3 - Rink Floor in Arena
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4.0 UPGRADE OPTIONS
The following upgrade options are explored in depth to investigate their feasibility, code compliance,
advantages and disadvantages. The upgrade options have been separated into three subsections: Ice Plant
Machine Room exhaust, Arena dehumidification, and consideration of an energy audit. Capital cost
estimates for recommended upgrades are listed in Chapter 5.0.
4.1 ICE PLANT MACHINE ROOM EXHAUST
The Client requested that TBTE investigate the mechanical layout of the Ice Plant Machine Room and
make recommendations for code compliance. After inspection of the Ice Plant Machine Room, TBTE
found several mechanical items that did not comply with the CSA-B52 Mechanical Refrigeration Code.
Items not complying with code are noted as follows:
- There is no source of supplementary heat in the machinery room.
- The presence of a grille open to the corridor compromises the machine room’s fire rating.
- Make-up air for the machine room is not ducted directly from outside.
- Remote switches are not located outside the machine room to operate ventilation equipment.
- It is unclear whether existing gas detection system is wired to activate existing exhaust fan.
Options proposed by TBTE in the following Sections remedy the issues noted above. However, Option 1
considers the installation of two new fans, while Option 2 considers installation of a heat recovery
ventilator to utilize waste heat from the space.
4.1.1 Option 1 – New Supply and Exhaust Fans
TBTE’s first proposed Option involves removal of the existing exhaust fan and installing new supply and
exhaust fans complete with new controls to satisfy code requirements.
Both new fans would be inline, direct-drive box-style units using 115/1/60 power. The fans would use
electronically commutated (ECM) motors for efficiency and variable-speed operation. The exhaust fan
would be installed in the vertical segment of existing exhaust ductwork and outfitted with a motorized
damper. All ductwork between the motorized damper and fresh air intake would be insulated externally.
The existing make-up air grille would be removed and the opening would be used for a new supply duct.
The new duct would be routed from the southeast exterior wall down the basement corridor, through
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the former grille opening and to the west side of the Ice Plant Machine Room. The duct penetration into
the machine room would be sealed with intumescent fire-rated caulking. A supply fan would be installed
within the new supply duct in the hallway. The fan would be installed complete with filter box, duct-
mounted hydronic heating coil, motorized damper and associated external duct insulation. The fan
system would have a switch mounted on the corridor wall outside the Ice Plant Machine Room.
Under normal operation, the fans would be controlled by both temperature and occupancy sensors.
When temperature is acceptable and there are no occupants, the fan system would be off with dampers
closed. Upon occupancy detection, the fans would run for a specified period of time. If internal space
temperature is above both the ambient outdoor air temperature and the space thermostat setpoint, the
fans would be activated to aid in cooling the space. The thermostat would output a 0-10 VDC signal.
If the gas detection system senses an alarm condition, both fans would be activated and kept on until
the gas detection system is not longer in alarm. If incoming air temperature is lower than the space
setpoint, a hydronic heating coil would be activated to bring air to 60°F before delivery.
To satisfy the code’s requirement for a dedicated heating source, a hydronic unit heater would be
installed at ceiling height on the west end of the Ice Plant Machine Room. The unit heater would be
activated by a standalone, wall-mounted thermostat to maintain a minimum space temperature of 65°F.
In summary, Option 1 explores the possibility of employing high-efficiency, variable-speed ECM fans in
the Ice Plant Machine Room. Variable speed fans are desirable in the warmer months, as they conserve
energy. However, it is likely that the fans would rarely be used during the winter since heating is
accomplished by the standalone unit heater.
In addition, more complex controls would be required to enable variable speed functionality of the
ventilation fans. Since the Community Centre only operates the ice plant equipment during the winter
months, savings from variable speed operation would not be realized.
For these reasons, TBTE does not recommend Option 1.
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4.1.2 Option 2 – Heat Recovery Ventilator
TBTE’s second proposed Option shares many traits with Option 1. However, instead of installing two
separate variable-speed fans, Option 2 explores the installation of a consolidated, constant-speed heat
recovery ventilator (HRV). Like Option 1, this proposed Option involves the installation of a hydronic unit
heater operated by a local standalone thermostat set to 65°F. Similarly, existing exhaust ductwork
would be re-used where possible, a new fresh air duct would be routed as noted previously and
motorized dampers and insulation would be employed as noted previously.
However, in place of separate, variable-speed exhaust fans, a single HRV would be installed outside the
Ice Plant Machine Room, connecting to existing exhaust ductwork. The HRV contains a constant-speed
supply and exhaust fan as well as an internal filter bank, several fixed speed settings and a single-point
power connection. An HRV is used for recovery of waste heat to reduce energy bills. In the winter, the
unit extracts waste heat from warm, interior exhaust air and uses it to pre-heat the incoming, cold air at
efficiencies of approximately 55%. The HRV core is made from aluminum to ensure that the unit is
unaffected by any chemicals that may pass through.
However, an HRV’s core is prone to frost buildup and damage in the winter season. To mitigate this, a
duct-mounted hydronic heating coil would be installed upstream of the HRV to pre-heat the air to an
acceptable temperature of 20°F. While some overall efficiency is lost in this process, the lack of frost
buildup will significantly lengthen the HRV’s useful life expectancy. A post-heat coil would also be
employed to heat incoming air to a neutral, comfortable temperature. It should be noted that hydronic
coils cannot be used until the boiler system loop is charged with glycol solution as per TBTE’s design.
The HRV would be activated on a call for cooling when ambient conditions permit, upon occupancy
detection and in alarm conditions as sensed by the gas detection system. An occupancy sensor and
thermostat with two sensors (indoor and outdoor) would be installed to enable proper system control.
Since the HRV is constant speed, it would not be capable of variable-speed economizer-style cooling as
described in Option 1. However, since the ice plant equipment is only used in the winter, benefits of
using variable-speed fans is negligible. In addition, without the need for variable-speed operation,
control logic and equipment become less complex and more economical.
TBTE recommends proceeding with Option 2 due to its relative simplicity, energy saving methods and
lower up-front labour costs.
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4.2 ARENA DEHUMIDIFICATION
The Client requested that TBTE investigate the feasibility and options associated with implementing
dehumidification processes in the Arena. As discussed in Chapter 3.0, TBTE found that the roof itself did
not have insulation and was in poor condition. Its replacement is recommended in a separate TBTE Roof
Study.
Currently, the Arena does not have a means of dehumidification and ventilation is minimal, with a
single, manually-operated exhaust fan being used when the Zamboni is operated. There have been
issues with condensation dripping on the ice surface reported by the Client.
There are generally two forms of dehumidification used today; mechanical and desiccant-based
dehumidification. Mechanical dehumidification involves the use of the conventional refrigeration cycle
complete with refrigerant, compressors, evaporator coils and condenser coils. The temperature of the
incoming air is reduced drastically past its dew point using an evaporator coil, forcing much of the
moisture to separate from the air and fall into a drain pan. The mechanically cooled air is then reheated
with the hot, compressed refrigerant passing through a condensing coil and delivered to the space.
Desiccant dehumidification is accomplished by passing moist ambient air through an absorbent, slowly
rotating desiccant wheel. The wheel absorbs ambient moisture and returns the dry air to the space. To
remove moisture from the wheel, a gas burner
draws in outside air and raises its temperature
above ~200°F. The hot air then passes through a
small segment of the desiccant wheel and
extracts its moisture. The moist, hot air is then
exhausted to the outdoors. The process is
graphically outlined in Figure 4.1.
Options proposed by TBTE in the following Sections explore both dehumidification methods. Option 1
considers mechanical dehumidification and Option 2 considers the use of a desiccant dehumidifier. Both
options will consider the use of the space on top of the announcer’s booth, as it is supported by
structural steel of adequate size to support a new unit. Units considered shall be sized to remove an
equivalent of 60 pounds of water per hour from an incoming airstream at 65°F.
Figure 4.1 - Desiccant Dehumidification Process
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4.2.1 Option 1 – New Mechanical Dehumidifier Units
TBTE’s first proposed Option involves the implementation of mechanical dehumidification in the Arena.
To determine the required unit size, TBTE performed calculations using design criteria specified in the
previous Section. As part of the sizing process, TBTE accounted for a fundamental limitation with
mechanical refrigeration systems. Air to be dehumidified cannot be cooled lower than 32°F or freezing
of components would occur, limiting performance and damaging components.
TBTE determined that the unit would need to capable of at least 13,000 CFM and have a cooling capacity
of 35 tons of refrigeration (TR) to accommodate the design criteria while keeping the process air above
freezing. A single unit of this capacity would be very large and would not fit on top of the announcer’s
booth. To accommodate, two identically sized units would be placed on opposite corners of the facility,
each operating at 6,500 CFM with a cooling capacity of 17.5 TR. One unit would be mounted above the
Announcer Booth on a new, fabricated and structurally reinforced platform using existing structural
steel. The other mechanical dehumidification unit would require a completely new stand to be
constructed in the east corner of the Arena complete with structural steel columns, beams, foundation
and platform. The construction of such a platform would be costly. Drains would be added to both
platforms and routed to nearby sanitary lines. Condensate pumps would likely be required.
It should be noted that complex controls and additional equipment may be able to enable subcooling of
the air below 32°F. By cooling below the freezing point, more moisture removal can be achieved at
lower volumetric flow rates, ultimately reducing the size of the unit. However, the additional controls
and equipment are not economical and were neglected in TBTE’s calculations for simplicity.
Mechanical dehumidification units are typically more cost-effective up-front than desiccant-based
equipment. However, since two units are required with large volumetric and cooling capacities, the use
of mechanical refrigeration is no longer economically feasible. The large capacities are a direct result of
the low incoming ambient temperature. For this reason, mechanical dehumidification is typically only
used for warm air applications. In this case, use of mechanical dehumidification is cost-prohibitive.
As a note, since mechanical dehumidification systems use refrigerant, additional safety measures would
need to be implemented to comply with code regulations.
For the reasons described in this Section, TBTE does not recommend Option 1.
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4.2.2 Option 2 – Desiccant Wheel Dehumidification Unit
TBTE’s second proposed Option involves the implementation of desiccant-based dehumidification in the
Arena. To determine the required unit size, TBTE performed calculations using design criteria specified
in the previous Sections. However unlike Option 1, dehumidification capacity is not limited by the
freezing point of water. Since desiccant-based dehumidification involves heating air instead of cooling,
more water can be extracted per unit air volume passing through the unit.
TBTE determined that the design criteria can be met using a 7,500 CFM dehumidification unit using a
400 MBH propane burner. The unit would fit in the existing unused space above the Announcer Booth,
seen in Figure 3.3. However, the outer walls of the booth would need to be removed to connect new
structural steel to existing support steel. The new steel would support a platform above the Announcer
Booth. Some sprinkler piping would require reworking to suit the new platform layout. The platform
would be accessible with a ladder mounted on the exterior of the Announcer Booth. If desired, the
bottom rungs of the ladder can be elevated off the floor to discourage unauthorized access to the
platform.
The proposed desiccant dehumidifier would be capable of taking in fresh air to ventilate the rink while
maintaining interior moisture levels. In the fall season when outdoor humidity is at its peak, it is
estimated that the unit would be able to accommodate up to 3,500 CFM of outdoor air. As the season
progresses and outdoor humidity levels fall, the ventilation rate can progress up to the full flow of the
unit at 7,500 CFM. The amount of outdoor air supplied would be controlled with a motorized damper
connected to a CO2 sensor in the return air ductwork.
A humidistat mounted at eye level on the Announcer Booth wall would control the on/off operation of
the dehumidification unit. The target humidity level for the rink space is recommended to be between
35% and 45% relative humidity.
TBTE recommends proceeding with Option 2 as it provides the most benefit to the space and is more
cost effective than Option 1, both in up-front costs and overall operational cost.
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4.3 ENERGY AUDIT
Throughout TBTE’s walkthrough of the site, it was noted that much of the mechanical equipment in use
is old, inefficient and poorly controlled. Though the boiler system and central roof areas are slated for
high-efficiency upgrades, there are many other opportunities for operational cost savings at the facility.
For example, the ice plant equipment generates large quantities of heat for use in the refrigeration
process and the heat is rejected directly to the atmosphere. There are many ways to capture the waste
heat and utilize it in other areas of the facility.
TBTE recommends that the Township of Manitouwadge pursues a complete-building energy audit for
the Manitouwadge Community Centre. The purpose of an energy audit is to investigate each point of
power and resource consumption in the facility and evaluate associated optimization or upgrade
options. Energy audits closely evaluate building consumption levels for fuel, electricity and water as well
as overall code compliance. Optimization or upgrade options are made regarding existing mechanical
equipment, electrical equipment, controls, plumbing fixtures, building usage as well as behavioural
patterns by staff.
First, a model is created with an energy simulation program that mimics existing conditions and existing
resource consumption levels on an hour-by-hour basis over one calendar year. Next, optimization
processes and upgrades are identified and implemented in the model. The resource conservation results
are then compared to estimated capital cost to determine payback period.
TBTE believes that an energy audit would be an invaluable resource in eliminating unnecessary resource
consumption, upgrading existing equipment and optimizing existing building processes. TBTE routinely
conducts energy audits for municipal organizations and has seen great success in the past. Most
recently, an energy audit at an arena in Thunder Bay, ON identified upgrades and optimizations that, if
implemented, are expected to lower the overall operational cost of the building by 33%. A consulting
cost estimate for the Work is included in the following Chapter.
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5.0 COST ESTIMATES
The following Chapter includes cost estimates for the three TBTE-recommended upgrade options. TBTE
recommends that upgrades outlined in Sections 4.1.2 and 4.2.2 be combined into a single project to be
undertaken in conjunction with future roofing, boiler and accessibility upgrades. Note that consulting
fees for upgrades in 4.1.2 and 4.2.2 are not included in the construction cost estimates.
The following cost estimate is an opinion of probable cost and is Class D in accuracy. It should be noted
that a 20% contingency allowance has been included to account for design related changes and
unforeseen construction issues. It is assumed that all work shall be completed within regular working
hours and will require travel to and from Thunder Bay, ON. Costs are expressed in Canadian Dollars
(CAD). Harmonized Sales Tax (HST) has been excluded from the cost estimate.
New Ice Plant Machine Room HRV $33,000.00
New Desiccant Dehumidifier $188,500.00
Total Direct Costs $221,500.00
Travel, Accommodations $36,250.00
General Contractor OH&P $58,750.00
Total Indirect Costs $95,000.00
Contingency (20%) $63,300.00
Energy Audit (Entire Facility) $28,000.00
Grand Total: $407,800.00
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6.0 CONCLUSION
To conclude, the Design Team reviewed the Client-specified project goals and conducted field work at
the Manitouwadge Community Centre pursuant to those requirements. Mechanical upgrade options
and recommendations have been presented, along with analysis and cost estimates.
Notice to Readers
All information in this Report is based on the history provided by the persons interviewed, conditions
observed at the site visits and archived documents made available. All recommendations are based on
this information and the remedial options are prescribed accordingly. TBT Engineering Ltd. has not
accounted for any defects, damage or deterioration or any changes in conditions that might have
occurred after the date of site investigations and cannot comment on or provide recommendations for
such defects and changes. This Report does not absolve the Owner of the responsibility to schedule
inspection and perform regular maintenance and repair any damage or deterioration that the building
and site may experience in the future.
TBTE does not assume responsibility for the accuracy of the cost estimates as they are preliminary at this
level of investigation. Cost estimates are to demonstrate the magnitude of costs and are for reference
only at this stage. Costs were calculated in Canadian Dollars (CAD) and without HST.
7.0 CLOSURE
We trust the above meets your requirements. If you have any questions or require clarifications, please
contact the undersigned at your convenience.
Sincerely,
ON BEHALF OF TBT ENGINEERING LTD.
Prepared by:
JP Eras, B.Eng.
Mechanical EIT