Ice Pile Air Conditioning Joseph Cooper: Project Lead Kylie Rhoades, Clara Echavarria, Jonathon Locke, Alex Gee

Agenda Background Problem Statement (Input on EER table) Customer Needs Functional Decomposition Specifications/Constraints/Given Concept Experiment Concept Development (Input on alternate designs) Concept Decision Heat Exchanger Calculations (Input on inlet temperatures) Initial Visual Representation of Unit Design

Project Background and Summary RIT has a goal of becoming carbon neutral by 2030 and a continuous vision of campus expansion. RIT will soon be the home of a brand new ice arena as well as the current home of Ritter Arena. Mission: Design a method to extract the cooling energy from a volume of ice (generated from an ice rink) effectively and efficiently. On a game day at an ice rink, there are approximately 5 Zamboni “dumps”, summing up to 500 ft 3 (14.15 m 3 ) On a typical day of operation, 100 ft 3 (2.83 m 3 ) is discarded. According to a density test, this will weigh approximately 2000 kg per load or 10,400 kg on a game day (per 5 loads)

Problem Statement Create a testing unit to which will demonstrate the feasibility of obtaining a cooling capacity from waste ice. This small scale proof-of-concept will be in the form of an air cooling unit. This testing unit is to be comparable (ideally found much better) to cooling efficiencies of a typical water or evaporative cooled condensing unit with a COP of 3.8

Equal to a COP of 3.8

Customer Needs

Functional Decomposition Tree

Specifications and Constraints

Preliminary Concept Experiment Purpose: Suspicion of creating an air gap around a pipe is thought of in theory Run test to find if we are able to have a vertical heat exchanger pipe in the ice box, and observe ice behavior during melting in this case. After about 35 minutes:

Concept Development

Concept One ProsCons Auto Ice SettlingCrush Piping Known Ice-Heat exchanger SAPump Required Closed Loop Allows for Possible CoolantPiping Cost ($$) No Filter NecessaryMaintenance of Coolant Additives Cleaning of Tank Around Pipes

Concept Two ProsCons Open system without refrigerant.Unknown ice behavior during melting. Auto-settling of ice.Recirculation of the same water (will not get the full cooling effect). No pipes needed.Pump required. Need screen for pumping loop. High enough flow rate?

Concept Three ProsCons No pump  Less power in.Waste water. No pipes needed.Need to source the water. Water in is about 55 0 F – consistent input temp. Enough pressure from water to outweigh line losses? More testing/less theory.

RiskRankProposed Mitigation Is there a high enough flow rate to avoid cavitation? 2Based on pump flow rate, start with enough water to eliminate this risk until we understand how the system behavior. Unknown amount of exposure between working fluid and ice causing a low cooling rate. 3Different spray patterns over top of ice to ensure even melting. If this is not helping, revert to heat exchange Debris entering pump loop causing pump/system failure. 3Implement a screen to filter out any unwanted debris. Water leakage into component area. 1Keep elements elevated from base of their compartment and/or seal them off. Concept Risk Assessment for Selection Likelihood Scale 1Low Risk Likelihood 2Moderate Likelihood 3High Likelihood

Selected Path for Design: Concept 2 Concept 2 includes benefits from both 1 and 3. Can be fitted with a heat exchanger (Concept 1) if needed for appropriate cooling. Heat exchanger will require: Design Lead Time Budget/Cost

Coolant to Air Heat Exchanger Background: Initial calculations are done with copper tubing Future plans are to use a finned radiator Coolant has been chosen as water Air is to be moved evenly by 2 DC fans with flow rates required by radiator Pump to be sized based on radiators and associated head losses

HVAC Requirements Used to size coolant to air heat exchanger System Design Parameters*: Room Height= 7 ft Room Width= 8 ft Room Length= 8 ft Room Volume= 448 ft 3 Occupants= 1 *Based on average room size

HVAC Requirements contd. Volume (ft 3 ) x 6 = BTU/hr req. 1 Occupant = 500 BTU/hr* System: Total (BTU/hr) = 448 ft 3 x occupant x 500 BTU/hr Total (BTU/hr) = 3188 BTU/hr  Min req. by design *equal to avg. rate of heat energy produced by a human at normal activity levels

Cross-Flow Heat Exchanger Cross Flow = Air Tube Flow = Water

Given parameters for Initial Hx: Water Inlet Temperature = 0°C Qwater = 1 gpm Air Inlet Temperature = ~30°C Air Flow Rate = CFM or 3 m 3 /min ½” Copper Tubing

Prototype Output Assume: Pure Ice at 0 o C 5 gallon tank 3.5 gallons of ice 1.5 gallons of H 2 O 300,000 J/kg latent heat of ice 917 kg/m 3 density of pure ice 736 kg/m 3 experimental density of Zamboni shaved ice 2773 BTU storage in Zamboni Ice 3992 BTU/hr Cooling Load of Heat Exchanger 45 Minutes of Run Time

Copper Tube Heat Exchanger Results Total Cooling Load= 1.08 KW or 3692 BTU/hr Required length of ½” diameter tubing= 96 ft Tubing Layout: 15” of straight tube 1.5” diameter elbows 1” gap between tubes Tubing section (HeightxWidthXDepth)=16.5”x3.5”x.5” Total Size (HeightxWidthXDepth)= 16.5”x19.375”x8”