ENERGY SMART TIPS FOR ICE ARENASedge.rit.edu/content/R12420/public/Ice Arena Niche Market...To determine where to spend money for the greatest return on investment, it is helpful to

Many communities across the state of Illinois have ice arenas. By their nature, these buildings are large energy users requiring satisfaction of simultaneous heating and refrigeration loads in proximate space. One of the first tasks that SEDAC performs when analyzing a building is to benchmark (or compare) the building’s energy usage intensity (EIU) to other buildings of similar use to assess how well the particular facility is performing.

As stated in a recent article titled Improving Efficiency in Ice Hockey Arenas written by ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers), a general survey of ice arenas in Quebec found that for an average sized hockey arena facility of 34,000 square feet, energy consumption of the most energy efficient arenas is

approximately 800,000 kilowatt hour per year (23.5 kWh/sf/yr) and the least efficient ones consume nearly three times that much energy at 2,400,000 kWh per year (70.5 kWh/sf/yr).

This wide range in energy consumption points toward the probability that there are several opportunities for energy and cost savings in many ice arenas. Some Energy Cost Reduction Measures (ECRMs) also reduce wear on equipment, thus extending its useful life and reducing maintenance requirements.

Several ECRMs are available to help reduce operating costs in ice arenas. Improvements can be classified into five different categories: resurfacing and refrigeration; building envelope; lighting; heating, dehumidification and ventilation; and low-cost or no-

cost efficiency improvements which, even with limited budgets can be implemented to begin saving money and energy.

In an ice arena, two main factors influence cost: 1) the refrigeration system and associated tasks for operations and maintenance of the ice sheet, and 2) heating, ventilation, and dehumidification of the stands, rink, locker rooms, and common areas (such as lobbies). Several cost saving opportunities are available with very reasonable payback periods. These items are within a designer and/or operator’s purview to impact and effect a 40% energy savings: the design and operation of the refrigeration, ventilation and heating systems, and the integration of the heating and refrigeration systems (with heat recovery). This brochure highlights some of these opportunities.

If you need assistance finding qualified contractors or suppliers, the Smart Energy Design Assistance Center can help. Our database of pre-qualified service providers includes reputable professionals in a variety of fields, including energy auditors, financing providers, and dealers/installers of geothermal heat pumps/high efficiency HVAC, efficient lighting, solar, and more. Download a free copy of our list of suppliers at SEDAC’s website under the header “Service Providers.”

SEDACILLINOIS’ ENERGY E F F I C I E N C Y I N F O R M A T I O N CLEARINGHOUSE

ENERGY SMART TIPS FOR ICE ARENASFROM THE ILLINOIS SMART ENERGY DESIGN ASSISTANCE CENTER

To determine where to spend money for the greatest return on investment, it is helpful to know what systems consume the most energy and for what reason. Figure 1 illustrates typical energy use in an ice arena. Not surprisingly, the refrigeration system consumes the greatest amount of energy (45% of total energy use).

To better understand refrigeration energy use, it is important to look at the loads on the refrigeration system. Table 1 shows a breakdown of the different loads on the refrigeration system. The seven main loads on the system are heat gain from air convection, heat gain from ceiling radiation, ground heat gains from below ice slab and heat gains in coolant piping headers, ice resurfacing, lighting, coolant pump, and skaters.

Make Commitment

Assess Performance

& Set Goals

CreateAction Plan

ImplementAction Plan

EvaluateProgress

RecognizeAchievements

Re-A

ssess

ENERGY STAR®’S 7 STEPS FOR ENERGY MANAGEMENT

Make a CommitmentRecognize that the economic, environmental and political impacts of energy consumption are sufficient motivation to change our energy use patterns.

Assess PerformanceKeep a record of energy use and costs. Benchmark your facility by comparing its energy performance with similar sites. Establish a baseline and analyze your energy use patterns.

Set GoalsReview your objectives and constraints. Establish priorities and set measurable goals with target dates.

Create an Action PlanDefine the technical steps. Apply proven methods to increase energy efficiency or get specialized guidance. Assign roles and resources. Consider rolling savings from earlier efforts into future, more complex initiatives.

Implement Action PlanInstall equipment and change operational procedures. Establish a maintenance schedule. Train equipment operators and building occupants on the changes. Track and monitor conditions.

Evaluate ProgressCompare current performance to established goals. Understand what worked well in order to identify best practices. Adjust procedures, goals, and schedule the next evaluation.

Recognize AchievementsProvide internal recognition for efforts and achievement of individuals and teams. Seek external recognition from government agencies, media, or third party organizations.

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Figure 2. ENERGY STAR’s steps for energy management

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TYPICAL ARENA ENERGY USE

Figure 1. Energy use (calculated by Energie Innovation)

Table 1. Loads on refrigeration system

ENERGY COST REDUCTION MEASURES FOR ICE ARENASLOW-COST/NO-COST EFFICIENCY IMPROVEMENTSLow-cost and no-cost improvements target improved control and facility operational adjustments: - increase ice temperatures during unoccupied periods, free skating, and figure skating. - reduce ice sheet thickness. - use reduced or floating head pressure controls on the refrigeration system (this modification will reduce effectiveness of heat recovery. Cost savings analysis can balance the trade-off between an improved refrigeration cycle or a more efficient heating cycle). - program night setbacks on space heating and ventilation. - reduce coolant flowrate according to schedule and occupancy.

LIGHTINGHigh efficiency lighting improvements reduce electricity use for lights and reduce the amount of heat input from lights. These following measures will help lower both electricity and refrigeration costs: - reduce light intensity over the stands. - install high output T5 or T8 fluorescent lights. - consider occupancy sensors for areas with intermittent use - upgrade to a highly reflective ceiling to reduce lighting requirements (can also be accomplished with low-e paint). - consider modulating lighting levels according to the activities taking place (Table 2 shows recommended illumination levels for Minnesota’s public ice arenas).

BUILDING ENVELOPEReducing radiative heat gains to the ice by making adjustments to the building envelope greatly reduces the load on the refrigeration system. A very common and effective solution is to install a low-emissivity radiant ceiling barrier. This highly reflective barrier is usually a polished aluminum surface laminated to a vinyl, polypropylene, or fiberglass backing. It is suspended from the ceiling as illustrated in Figure 2. The barrier shields the ice surface from being exposed to the warm ceiling surface, thus reducing radiative heat gains.

Additional building envelope recommendations include those suggested for most buildings: - properly insulate walls and roof. - install insulated doors to reduce conduction losses. - replace worn weather-stripping & caulking for airtightness.

ACTIVITY FOOT-CANDLESPro Hockey 100Amateur Hockey 50Recreational Hockey 20Figure Skating 15Curling 10-20Recreational Skating 10

Table 2. Recommended ice rink illumination levels for Minnesota’s public ice arenas.

Figure 2. Low emissivity ceiling (from the Energy Efficiency Guide for Municipal Recreation Facilities)

HEAT RECOVERY FOR HEATINGAND HUMIDITY CONTROL

Ice arenas have substantial refrigeration and heating loads, making them prime candidates for waste heat recovery from the refrigeration process. Waste heat can be used to heat sub-slab brine, control the temperature and humidity of the interior climate, heat resurfacing hot water, or melt ice scraped off by the resurfacer. Heat recovery on exhaust air to preheat incoming outdoor air should also be considered.

REDUCE CONVECTION GAINSConvective gains occur when forced air heating systems for the rink and stands disturb the air stratification above the ice sheet, creating air currents that increase refrigeration loads. These convective gains can be reduced by minimizing heating and ventilation and by only heating spectator areas when occupied. Outdoor air can be controlled using CO2 sensors for locker rooms and common areas and CO sensors for rink

areas to remove pollution from the fossil-fueled resurfacing machine exhaust. Ventilation flow rates can be lowered using variable frequency drives (VFDs) on the air handler motors.

REDUCE SPACE HEATINGReducing space heating also lowers the load on the refrigeration system. Typically, this load can account for more than 30% of the refrigeration system’s energy consumption. Conditioning and refrigeration loads can be reduced by lowering set point temperatures in the stands, particularly during unoccupied periods. Ideally, ventilation should be supplied only to maintain indoor air quality. Heating of spectator areas should be accomplished using radiant heating systems (floor or infrared). Savings are also possible by installing programmable controls that save 5-15% of annual refrigeration costs.

HEATING, VENTILATION, AND HUMIDITY CONTROL ECRMs

SEDACWho We AreThe Smart Energy Design Assistance Center (SEDAC) was established to support the Illinois Smart Energy Design Assistance Program which works to increase the efficient and effective use of energy throughout Illinois. SEDAC is sponsored by the Illinois Department of Commerce and Economic Opportunity and is managed by the School of Architecture at the University of Illinois at Urbana-Champaign and the 360 Energy Group.

What We DoThrough the Illinois Smart Energy Design Assistance Program, SEDAC provides advice and analysis enabling facilities in the state of Illinois to increase their profitability through the efficient use of energy resources. These state-funded technical services can identify opportunities for energy savings through intelligent building design and efficient building components and systems.

How to Reach UsSMART ENERGY DESIGN ASSISTANCE CENTER

University of Illinois atUrbana-Champaign1 Saint Mary’s RoadChampaign, IL 61820TEL: 1-800-214-7954EMAIL: [email protected]

Improving Efficiency in Ice Hockey Arenas http://bookstore.ashrae.biz/journal/download.php?file=nichols060109.pdf

Rink Magazinehttp://www.pbmrefrigeration.com/images/RINK%20Magazine%20article%20july-06.pdf

LEDs Magazine: Case Studyh t t p : / / w w w . l e d s m a g a z i n e . c o m /casestudies/19287

Temperature Optimization in Standshttp://canmetenergy-canmetenergie.nrcan-rncan.gc.ca/fichier.php/codectec/En/2003-066-5/2003-066-5e.pdf

Energy Efficiency Guide for Municipal Recreation Facilitieshttp://www.hydro.mb.ca/your_business/recreation_facilities/recreation_manitoba_rinks.pdf

Cost-Effective Energy Efficient Improvements for Minnesota’s Public Ice Arenas: Overview of 20 Optionswww.mncee.org/pdf/tech_pubs/ice_fact.pdf

Energy Efficiency Project Analysis for Supermarkets and Arenaswww.retscreen.net/download.php/fi/473/1/course_eesa.ppt

ENERGY SMART RESOURCES FOR ICE ARENAS

RESURFACING AND REFRIGERATION ECRMsOPTIMIZED REFRIGERATION SYSTEM

Possible options include compressor sequencing, floating head pressure, variable flow or dual-drive brine pumps, variable frequency drives onevaporators, high efficiency motors and soft-start controllers. The best way to evaluate the advantages of improvements is to simulate the operating equipment.

ICE SHEET ASPECTSThe thickness and temperature of the ice sheet and how it is maintained all impact energy use. Different activities need different surface temperatures. Hockey requires hard ice and figure skaters prefer soft ice, so brine temperatures must be adjusted accordingly.

Keeping the temperature of the ice as high as possible reduces refrigeration loads, and increasing the ice temperature a single degree can save 6% annually in refrigeration costs. Consider raising the ice temperature when the rink is unoccupied.

The ice surface temperature can be determined with an infrared sensor. The sensor is typically mounted or hung above the ice from a beam or score clock and oriented down at the ice. This type of sensor provides better control of the ice surface temperature than embedded sensors.

The thickness of the ice also affects the temperature at which the brine must be circulated to chill the ice. The thicker the ice, the cooler the brine must be, and cooler brine creates greater refrigeration loads. Equipment is available to automatically reset brine temperatures based on a schedule of events throughout the day.

Note that to drop brine temperature 2°Ftakes only one to two hours if the ice

is kept thin (about 1”). It is possible to save up to 8% of compressor energy consumption when variable brine temperatures are implemented. If variable temperature brine controls are installed, we recommend placing a separate slab sensor to monitor ice temperatures and ensure that the ice performs as required, independent of other loads.

MAINTENANCE AND RESURFACINGCity water is heated and transferred to the ice resurfacing machine to provide a better bond to the ice sheet and to melt and fill in cracks caused by skate blades. By switching to demineralized water the need for heating is eliminated because pure water bonds very easily to the existing ice sheet .

Two additional benefits of using unheated demineralized water are that the cooler resurfacing water reduces the load on the refrigeration equipment, and pure water provides a harder ice surface that is more resistant to cuts. Water can be demineralized using either an ion-exchange method or a reverse osmosis filter; however, reverse osmosis will increase water usage.

Electric versus internal combustion powered ice resurfacing machines also impact energy use. We recommend switching to an electric resurfacer to reduce outside air requirements necessary for human comfort and improvement of interior air quality.

MAY 2011