How to improve the Arena’s water refrigeration plant: Some retrofits and upgrades can go a long way to successfully optimize your refrigeration plant and reduce the amount of energy needed to keep the ice frozen. Have you successfully incorporated some of these measures? Let us know and tell your story so that we can share it here and inspire others to take action!
Controlling temperature, energy efficiency and reliability of the ice plant can be achieved with a computer controlled energy management system. In comparison to the same refrigeration system without a computer control system, energy savings can be greater than 20%. An energy management system can adjust the plant to the present weather conditions and facility usage to run most efficiently. Pre-programmed settings can be applied for hockey, figure skating and public skating in which the ice temperature is adjusted automatically, including the lights above the ice, to match the current on-ice program. Off-hour programming will help to reduce energy consumption. It allows the ice temperatures to rise during nighttime hours, or inversely pre-chilling the ice prior to peak demand hours. Benefits: Efficient and reliable control of refrigeration system, brine pumps, ice temperature, lighting and illumination levels, ventilation equipment, heating systems, domestic hot water heating Less maintenance costs and extended equipment life Convenience […]
Refrigeration plants used in arenas provide necessary cooling to produce and maintain ice surfaces. The refrigeration equipment draws electricity; the highest ongoing non-labour cost in arenas. The refrigeration plant removes heat from ice pads and the condenser disposes of it outdoors. On average, as much as 7.2 million Btu of heat, or more than 2,000 kWh, are generated each day by an ice plant. Heat-recovery systems can harness heat as free energy from the refrigeration plant, which can provide overall heating savings of more than 75%. Most of the wasted heat available comes from the refrigeration condenser, but some heat can be recovered from the building’s exhaust air. Recovered heat can be used for space heating, domestic water heating, subfloor heating, slab heating, floodwater heating, ice melting, and preheating cold outdoor air for ventilation. Considerations: Some systems should be located below showers, and require simultaneous flow Use licensed professionals to install equipment […]
Variable-frequency drives (VFDs)—also referred to as variable-speed or adjustable-speed drives—allow induction-motor-driven loads such as condenser fans and brine pumps to operate at rotational speeds. VFDs are used in applications ranging from small appliances to large compressors. About 25% of the world’s electrical energy is consumed by electric motors in industrial applications, which can be more efficient when using VFDs in centrifugal load service. A variable speed drive controls motor speed and torque by varying the motor input voltage and frequency. Variable speed drives are expensive, yet the most efficient means of operation, as they match pump operation with the ice surface needs. By controlling motor speed to correspond with varying load requirements, retrofitting electric motors with VFD controls can increase motor energy efficiency—in some cases by as much as 50%. VFDs can also improve power factor and process precision, and they can deliver other performance enhancements and non-energy benefits such […]
Replacing glycol pump / brine pump, water pump and compressor motors with new energy efficient motors helps save electrical energy through decreased usage and makes the refrigeration plant more efficient. Install high-efficiency motors, soft start controllers: Using motors with a high-efficiency rating will increase the total system efficiency. Arenas can install soft-start controllers on the compressor motors. Soft-start controllers reduces inrush current and the resulting peak demand loads and reduces the strain on the compressor during the high torque generated at start up. Check with utility companies, as power bills can be reduced by using a soft-start controller and will depend on the method used to calculate the demand load. Benefits: Reduced cost Rebate programs they may offer to help pay for the greater efficiency Savings: Electricity CO2 Web resource: The News: Energy efficiency in the ice rink
Under the ice in arenas there is a slab that is above the embedded brine (used to keep the ice frozen) tube network. A brand new slab and energy efficient upgrades will result in gas, hydro and greenhouse gas savings (GHG). In older ice slabs (e.g. more than 30 years), many components will need to be replaced. This will ensure its ongoing availability to the many local ice user groups, and will avoid the added costs of emergency replacement. Over time, the ice slab will shift, which eventually causes the pipes underneath to crack and start leaking brine. Ice slab upgrade projects include: Disassemble the existing dasher boards and arena glass system Stabilize existing masonry walls which include structural framing and sheathing – this phase is required to be completed before the next phase Replace ice rink refrigeration piping system Removal and replacement of the concrete slab, including new heating and […]
Refrigeration systems are often designed for higher outdoor temperatures. As a consequence, the head pressure is higher than needed. This leads to high condensing temperatures and increased electrical consumption. Benefits: Especially in cold climates, modulating head pressure based on outdoor air temperature can yield refrigeration savings as high as 25%. Savings: Electricity CO2 Web resources: Carbon Trust: How to minimise head pressure in refrigeration
According to Madison Gas & Electric utility brine should be kept at a specific gravity of 1.20 to 1.22 for most efficient energy use. A hydrometer can be used to measure the specific gravity, or density relative to water. Brine should be warmed up to 60°F (apx. 15.6°C) before testing. Specific gravity is measured relative to water, which has a specific gravity of 1.0. To adjust the specific gravity, add calcium chloride flakes to increase (mix in a barrel and add through mixing valve), or dilute the brine with water to decrease. Experts recommend testing the brine annually by a lab regularly engaged in testing arena brine samples. Benefits: Insulating the brine storage tank, reduces cooling losses Reduced heating costs in the compressor room Savings: Electricity CO2 Web resources: Managing energy costs in ice rinks
Replacing old compressors with more efficient ones will save a lot of energy and maintenance costs.
In indirect refrigeration systems, brine is pumped through evenly spaced pipes in the rink floor. A liquid refrigerant absorbs heat from the brine and then pulls the heat out of the rink floor. Brine pump efficiency upgrades can improve the efficiency by 10-15% or even more. Often, these upgrades yield significant savings on pump maintenance and repair as well, which translates into less downtime and reduced environmental risks. Upgrading pumps include custom coatings for internal and external parts, shaft and seal modifications, bearing isolators and bearing-housing breathers. Some resources suggest installing dual-drive brine pumps, which allow for significant reduction in pump horsepower by stopping the large main brine pump and starting a lower-horsepower pony pump. In addition to the energy savings, there is the added security of a backup brine pump in the event of a failure. Of these, custom surface coatings typically provide the fastest return on investment. Benefits: Boost efficiency of […]
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