hvac study - manitouwadge.ca · manitouwadge community centre– hvac study tbte ref no.: 18-340-2...

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

November 23, 2018

ii

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

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