Sanitation: Ware Washers, Water Heaters and the Plumbing of the Future

Transcription

1 Food Service Technology Center Sanitation: Ware Washers, Water Heaters and the Plumbing of the Food Service Technology Center 1

2 Water Heating is a System Business As Usual Hot water systems in restaurants haven t changed much in 50 years Focus on designing and building it cheap Common characteristics Standard efficiency heaters Poorly performing distribution Low cost sanitation equipment Not an engineered system 2

3 Typical Design Process Locate water heater in a far corner out of sight and out of mind. Sanitation equipment is not a design priority fits into spaces left over in the kitchen. Hot water lines are thrown in to connect the heater to the appliances. Priority on maintaining required water pressure, meeting maximum flow, minimizing pipe failure and noise. Design for peak flow utilizes 65-year old Hunter s curve and counting fixture units. Conventional Design Heater Actual design for a small full service restaurant 3

4 Conventional Design - Loop 1 1 Comp Mop Heater 3 Comp Dishwasher Pre rinse 145 F Recirc loop 3 Comp Conventional Design - Loop 2 HS HS HS HS Hand Sinks (HS) Heater 120 F Recirc loop HS HS HS 4

5 Conventional Design - The Good Mop Dishwasher 3 Comp Pre rinse 145 F Recirc loop Clustering of sanitation equipment in kitchen Conventional Design - The Good Water heater is positioned centrally 5

6 Conventional Design - The Good In new installations, most dishwashers purchased are ENERGY STAR labeled Conventional Design - The Bad Heater is a standard efficiency 80% TE unit 6

7 Conventional Design - The Bad 110 ft. recirculation loop 105 ft. tempered recirc. loop 383 ft. total length Estimated installed cost of $5,100 Long lengths and large diameter pipes increase costs Conventional Design - The Bad 25ft 16ft HS Poor hot water delivery performance at hand sinks 7

8 Question: How many seconds does it take to get hot water from the recirculation line to lavatory sink with a 0.5 gpm aerator on faucet? seconds (acceptable) 8% seconds (marginal) 11% 32% seconds (unacceptable) 49% seconds (unacceptable) 25 feet in length ¾ inch dia. pipe Answer: How many seconds does it take to get hot water from the recirculation line to lavatory sink with a 0.5 gpm aerator on faucet? seconds (acceptable) seconds (marginal) seconds (unacceptable) seconds (unacceptable) 8

9 Optimized Hot Water Systems Upsize efficiency and downsize distribution Same installed cost as today s system Can cut the operating cost Improved hot water delivery performance Win, win, win for the utility, the end user, and their customer Partially Optimized Design - Dishwasher Eliminates the need for a tempered recirc line. Able to turn down the heater thermostat to 125 F. Heat recovery door type dishwasher installed Unit is ventless and requires only a cold water supply 9

10 Dishwasher Installed Cost Comparison No cost penalty in new installation Upsize efficiency and downsize installation cost ENERGY STAR Heat Recovery $9,500 Purchase cost $12,000 Ventless w/ Heat Recovery $3,000 Installation cost $3,000 $1,500 Dedicated exhaust hood system 0 $1,500 Exhaust system installation cost 0 $15,500 Dishwasher installed cost $15,000 $500 Installed cost savings! Partially Optimized Design - Distribution 110 ft. recirculation line 262 ft. total length Reduced to $3,300 $1,800 reduction in installed cost 10

11 Partially Optimized Design Pump Timer $100 Turns off pump for 10 hours during closing hours Install timer to reduce pipe heat losses overnight Partially Optimized Design Water Heater Heater is a high efficiency condensing 95% TE unit 11

12 Installed Cost Comparison Standard Efficiency Heater Standard Efficiency High Efficiency $3,700 Heater purchase cost $5,600 $2,900 Installation cost $3,200 $6,600 Total installed cost $8,800 High Efficiency Heater Cost premium of $2,200 Optimized Design Next Steps Mop Move to point of use electric heaters at select sinks Still room to improve this design 12

13 Optimized Design w/ Point-of-Use Heaters 1 Comp HS Mop 3 Comp Pre rinse 96 ft. total length Estimated installed cost of $800 6 Electric heaters installed cost of $2,400 Downsized distribution system, no recirculation System Installed Cost Comparison Conventional Partially Optimized Optimized Heater $6,600 $8,800 $11,200 Distribution system $5,100 $3,300 $800 Pump Timer - $100 - Dishwasher $15,500 $15,000 $15,000 Total installed cost $27,200 $27,200 $27,000 Upsize efficiency while maintaining a fixed installed cost! 13

14 Question: Point-of-use electric heaters are a mature technology Have you worked on a project that included point-of-use electric water heaters? 1. Yes 2. No 39% 61% Question: What are the barriers stopping point-ofuse water heating? Press the green square when complete. 1. Unfamiliar with technology 2. Performance issues 7% 10% 3. Life span 4. Heath department aversion 3% 13% 5. Electric water heating costs 13% 6. Limited availability 54% 14

15 Conventional Distribution Heat Loss Cost 110 ft. recirculation loop 105 ft. tempered recirc. loop Estimated annual heat loss cost of $625 Increased operating costs due to heat loss from 215 ft. of recirculation loop Partially Optimized Distribution Heat Loss Cost 110 ft. recirculation line Estimated annual heat loss cost of $295 One less recirculation line and reduction in outlet temperature reduces heat losses by 50% 15

16 Optimized Design w/ Point-of-Use Heaters 1 Comp HS Mop 3 Comp Pre rinse Equates to $0 in recirc line heat losses Annual Operating Cost of Dishwashers ENERGY STAR Heat Recovery 300 Daily use (racks/d) Actual flow (gal/rack) Total water use (gal/d) Water heater energy (therms/y) Makeup air energy (therms/y) Total gas use (therms/y) 0 43,600 Dishwasher energy (kwh/y) 46, Fan energy (kwh/y) 0 44,300 Total electricity use (kwh/y) 46,300 $7,600 Annual energy cost $6,950 - Heat recovery energy savings 35% - Heat recovery cost savings $650 Ventless with Heat Recovery 16

17 System Operating Cost Comparison Conventional Partially Optimized Optimized Hot Water Use (gal/day) Heater and Distribution (Gas) $6,890 $3,170 $2,430 Recirculation Pump (Electric) $240 $120 - Dishwasher (Electric) $6,810 $6,950 $6,950 Point-of-use (Electric) - - $780 Total operating cost $13,940 $10,240 $10,160 Improved hot water delivery performance Redundancy if main heater goes down Optimized System - Final Step Solar water preheating Preheat the cold water supply 10 to 30% solar fraction maximizes the performance from solar system 17

18 Hot Water Systems of Tomorrow Will move towards net zero-energy water heating Heat recovery and renewable energy technologies will become the primary water heaters 2 step approach 1 st step. Maximize heat recovery 2 nd step. Concentrated solar water heating Systems of Tomorrow - Dishwashers Advanced heat recovery ware washers are mature in Europe Allows larger ware washers to be placed completed off the hot water line And no longer require a dedicated exhaust ventilation system 18

19 Systems of Tomorrow - Dishwashers 2-stage exhaust heat recovery in conveyors 1 st stage: Heat exchanger (available in U.S.) 2 nd stage: Heat pump to recover extra heat and dehumidify air Discharges 65 F dehumidified air in to the room Heat Exchanger Heat Pump Systems of Tomorrow - Dishwashers Door-type and larger machines incorporate drain water heat exchangers to recover heat from 150 F drain water. Drain water heat exchanger That is three forms of heat recovery in one machine! 19

20 More Aggressive With Heat Recovery Heat from cooking appliances is vented out of the facility. Higher quality waste heat is available from appliances such as woks, conveyor broilers and ovens. Design for Heat Recovery Refrigerant heat recovery systems can recover heat from condensing units of walk-ins and ice machines on the rooftop. Perform effectively when positioned close to condensing units and the water heater. 20

21 Second Stage of Heat Recovery Concentrated solar hot water systems have the capability to boost the water temperature to 180 F. Allows for daily thermal storage Second Stage of Heat Recovery Large array of collectors are needed to increase solar fraction to above 75% to meet the evening heating load. Array elevated above rooftop equipment to maximize surface area and provide shading. 21

22 Recap High efficiency heaters, distribution systems and dishwashers can be installed at the same cost as conventional systems. Major benefit in reducing utility costs and improving hot water delivery performance. Its viable to incorporate heat recovery technologies and solar preheating in new facility designs. Thank You! Food Service Technology Center 22

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