Alex Gee Jon Locke Joe Cooper Kylie Rhoades Clara Echavarria Ice Energy Extraction

Background Hockey arenas are some of the most energy demanding and least efficient buildings Ice disposal from Zamboni amounts to 100ft3 per day, up to 500ft3 on a game day. Between 700kJ and 3500kJ of cooling are being wasted from phase change alone

Project Purpose Provide data on extraction efficiencies and methods o Coefficient of Performance (COP) o Type of working fluid, method of heat transfer (Convection? Conduction? Direct Contact?) Provide a look forward o Cost and energy savings potential from wasted arena ice o Potential of other similar sources (winter snowfall)

"Customer" Needs

Specifications

Constants and givens (from vendor) 1.CFM air, GPM water, rating (q) 2.Inlet temperatures (used to figure out the fluids’ densities and specific heat capacities) Constraints and Assumptions - Ideal gas - Incompressible flow - Constant Pressure (Cp) - Uniform Flow Output UA value at different flow rates of air and water Heat Exchanger Feasibility Calculations: Part 1 Design Calculations and Theory

Constraints and Assumptions - Ideal gas - Incompressible flow - Constant Pressure (Cp) - Uniform Flow Heat Exchanger Feasibility Calculations: Part 2 Design Calculations and Theory

Measured data 1.  T of water in and out of radiator 2.W in from “plug power meter” 3.Coolant Flow Rate Constants and givens 1.Fluid properties of water (density, Cp) Constraints and Assumptions Ideal gas Incompressible flow Constant Pressure (Cp) Uniform Flow Output Final/Overall COP of unit Final Efficiency Functional Diagram (Final Testing) Design Calculations and Theory

Total Assembly Cost: $493.06

Testing Overview Goal: Determine the best way of melting the ice (spray pattern) and optimize the water to ice ratio to achieve the highest COP possible.

General Procedure Guidelines Fill plumbing system Set valve to theory flow rate Constant Ice Volume: 30L Input desired Water Volume Turn on system fan and pump Take initial readings from all thermocouples Record values every 2 minutes For Part I only, take picture of tank every 4 minutes

Part I: Determine Spray Pattern Cross Design Single Input Downpipe Input

Part I: Determining Spray Pattern One test for each pattern o Constant Ice:Water Ratio: 30:10 L Data eliminated single input over tank o Cross and downpipe design equally better Downpipe design selected o Picked circulating downpipe by observation of better mixing performance

Part II: Optimization of Water Using downpipe design from Part I: o Constant Ice Volume: 30L o Varied Water Volume: 5-20L of Water (5L, 7.5L, 10L, 12.5L,15L, 20L) o Assumption: As water is increased from 5 to 20L, the resulting COP will be normally distributed Optimal Operating Point: 30/12.5L of Ice/Water

Results - Test vs Theory The experimental COP did not match the theoretical COP. Power draw of the system was ~30 Watts higher than expected, decreasing COP Budgetary and model restrictions (about $150 and 5 gpm) limited pump selection to oversized units that consumed 80 Watts more than an ideal pump.

Results - Test vs. Theory Cont’d. The fan had a 12% reduction in flow compared to the manufacturer’s data After recalculating the theoretical COP with this reduced flow and including 20% error bounds, the following table was produced. *These results match the experimental data

Conclusions Potential energy savings: >314% increase in COP from a traditional system is substantial. For every 1000 kW of cooling of the current system, the proposed system would provide ~3140 kW of cooling w/o affecting overall operating costs.

System Implementation Current RIT ice rink: Four separate, equal, cooling systems. They are comprised of two primary pumps that pump the “warm” fluid to a cooling tower, a second set of pumps that move the fluid through the condensers and the heat exchanger unit. There is potential to replace one of the four systems in the adjacent to the room where the Zamboni is stored. An ice dump pit could be placed in the floor of the storage room and water lines could be run to the adjacent room containing the heat exchanger unit (which could be reused to save on capital expenses).

A Look Forward Arena Ice from June-September o Assume minimum 100ft3 per day o Energy savings over conventional system of 22650MJ, amounting to $630 o 5-year savings  $3,150 Ice Arena Year Round o Assume minimum 100ft3 per day o Energy savings over conventional system of 67950MJ, amounting to $1,890 o 5-year savings  $9,450

Alternate Application The information learned in this project can be applied to similar ideas to help reduce the use of energy from other parts of campus: o Annual snowfall in Engineering Lot J Assume less than half of the snowfall (2.5m) is usable 200mx200mx1m (snow volume of L ot J) Energy savings over conventional system of MJ, amounting to $18,850 5-year savings  $94,250

Special Thanks Dr. Stevens ~ Theory Support Dr. Hanzlik & Mr. Wellin ~ Theory and equipment Rob Kraynik ~ Machine Shop Rick Lux ~ Mentor