7-i 

### CHAPTER 7. ENERGY AND WATER USE ANALYSIS
TABLE OF CONTENTS
7.1 INTRODUCTION .............................................................................................................. 7-1 7.2 ANNUAL ENERGY CONSUM PTION

................................ ............................................. 7-1 7.2.1 Equipment Class Energy Use and Harvest Rate Capacity ...................................... 7-2 7.2.2 Utilization Factor .................................................................................................... 7-2 7.3 ANNUAL WATER CONSUMP TION

................................ ............................................... 7-3
LIST OF TABLES Table 7.2.1 Total Annual Energy Usage ...................................................................................... 7-3 Table 7.3.1 Total Annual Water Consumption ............................................................................ 7-47-1 

### CHAPTER 7. ENERGY AND WATER USE ANALYSIS
7.1 INTRODUCTION This chapter presents the U.S. Department of Energy’s ( DOE’s ) analysis of annual energy and water usage at various efficiency levels of automatic commercial ice makers. These estimated values of annual energy consumption (AEC) in kilowatt-hours per year (kWh/yr ) and annual water consumption (AWC) in gallons of water per year are key inputs to the life

- cycle cost and payback period analysi s ( chapter 8 of the pr eliminary technical support document ( preliminary TSD)) and national impacts analys i s ( chapter 10 of the preliminary TSD). The goal of the energy use analysis is to generate a mean value and a range of energy use values that reflect actual use of an automatic commercial ice maker in commercial applications. Actual energy usage in the field often differs from that estimated by the test procedure because of variations in the system capacities chosen to serve the estimated load, operating conditions, user behaviors, and other factors. The remainder of this chapter discusses the methodology used to estimate the annual energy and water consumption for representative sized units for each automatic commercial ice maker equipment class.
7.2 ANNUAL ENERGY CONSUMPTION
For the preliminary analysis, DOE estimate d the AEC for every combination of equip ment class and efficiency level considered in the analysis. Estimated energy use per 100 pounds of ice, assumed equipment utilization factor , and rated maximum daily harvest rates for each combination are used to calculate a daily energy consumption value for the ice-making related function of the equipment. In addition to the ice- making related energy consumption, estimated daily standby energy usa g e is also added to yield a tot al energy consumption value for a single 24 -hour period. Multiplying the sum of the daily ice- making related energy and standby energy use by 365 results in the total AEC for each specific equipment class and efficiency level combination.
For automatic com mercial ice makers , the equation for AEC is:
AEC i, j 

### = (E i,j 

### ÷ 100 × H i 

### × U i 

### + SE i 

### × (1 – U i 

### ) ) × 365 Eq. 7.1
Where:
AEC i,j 

### = calculated annual energy consumption for equipment class i , at efficiency level j (kWh/year) , E i ,j 

### = estimated energy use for equipment class i , at efficiency level j (kWh/100 lb ice), H

i 

### = harvest rate for equipment class i (pounds of ice produced per 24 hours), U

i 

### = assumed utilization for equipment class i ( percent of time producing and harvesting ice),

and SE i 

### = estimated “standby” energy use for equipment class i (kWh/24 hours).7-2 

### 7.2.1 Equipment Class Energy Use and Harvest Rate Capacity For each equipment class , a baseline energy use value is estimated, noted as E fficien cy L evel 1. Level 1 is the initial value against which energy saving percentages are based. A more complete breakdown of how the incremental percentage savings values are derived is also described in c hapter 5 of the preliminary TSD

. Harvest rate capacity, which provides a representative value for the pounds of ice that can be produced for each ice -making equipment class, does not vary by efficiency level within an equipment class. The values used as estimates for energy use ( E i,j 

### )
, a nd harvest rate ( H

i 

### ) are taken from the engineering a nalysis presented in
c hapter 5 and are designed to be representative of a given equipment class.
7.2.2 Utilization Factor
Ice -making equipment is not assumed to be making ice 24 hours out of every day. Instead, a utilization factor ( U i 

### ) is used as the estimate for the percent of time the ice maker is actively producing ice. In the preliminary analysis, this value is consistent across all equipment classes and efficiency levels, and is estimated at 50 percent . The complement to the amount of time the ice

- making equipment is actively producing is the time that the ice -making equipment is not activ ely producing or harvesting ice. Energy used during non-producing periods is referred to as standby use energ y. Preliminary test data indicates that standby use represents an extremely small level of usage. As a conservative assumption, DOE used a v alue of 5 watts for all equipment classes, but believes the average value is actually lower. The standby loss assump tion yields a daily energy consumption of 0.12 kWh/24 hours. Calculated values for each equipment class and available efficiency levels are provided in Table 7.2.1

. Fo r each equipment class listed, AEC for the maximum available energy efficiency levels are also included in the table, and are found in column with the highest numbered efficiency level for that equipment class.7-3 

### Table 7.2.1 Total Annual Energy Usage
Equipment Class * Total Annual Energy Usage kWh/year EL 1 ** E L 2 EL 3 EL 4 EL 5 EL 6 EL 7 IMH

- W

- Small

- B 4 , 292 3 , 865 3 , 695 IMH

- W

- Med

- B 7 , 825 7 , 044 IMH

- W

- Large

- B 10 , 972 9 , 877 9 , 767 IMH

- A

- Small

- B 5 , 639 5 , 078 4 , 797 4 , 516 IMH

- A

- Large

- B 9 , 366 8 , 432 7 , 964 7 , 497 RCU

- Small

- B 11 , 328 10 , 310 9 , 632 9 , 462 RCU

- Large

- B 13 , 983 12 , 727 11 , 889 11 , 680 SCU

- W

- Small

- B 2 , 310 2 , 150 1 , 967 1 , 853 1 , 761 SCU

- W

- Large

- B 4 , 183 3 , 892 3 , 559 3 , 351 3 , 143 3 , 018 2 , 560 SCU

- A

- Small

- B 3 , 635 3 , 382 3 , 093 2 , 913 2 , 732 2 , 624 SCU

- A

- Large

- B 3 , 599 3 , 349 3 , 062 2 , 884 2 , 705 IMH

- W

- Small

- C 11 , 848 10 , 665 10 , 074 9 , 483 8 , 891 7 , 945 IMH

- W

- Large

- C 9 , 329 8 , 399 7 , 933 7 , 468 7 , 096 IMH

- A

- Small

- C 5 , 849 5 , 266 4 , 975 4 , 684 4 , 392 4 , 101 IMH

- A

- Large

- C 11 , 519 10 , 370 9 , 795 9 , 220 8 , 645 8 , 070 7 , 495 RCU

- Small

- C 12 , 158 11 , 272 RCU

- Large

- C 15 , 078 13 , 979 12 , 594 SCU

- W

- Small

- C *** SCU

- W

- Large

- C 3 , 471 3 , 350 SCU

- A

- Small

- C 3 , 635 3 , 382 3 , 093 2 , 985 SCU

- A

- Large

- C 5 , 387 5 , 012 4 , 583 4 , 314 4 , 046 3 , 778 3 , 456 *See c hapter 5, Table s 5.2.1 and 5.2.2 , for a description of these abbreviations. ** EL = efficiency level; EL1 is the baseline efficiency level ; EL2 through EL7 represent increased efficiency levels. *** DOE was not able to identify any existing products of this equipment class in ice maker databases. Hence, this equipment class was not analyzed, directly or by extrapolation. 

### 7.3 ANNUAL WATER CONSUM PTION
DOE estimated the AWC for each ice

- making equipment similar to the method used for calculating the AEC, the difference being that for the preliminary analysis DOE assumes that water consumption, potable or condenser, does not vary with efficiency lev els within a given equipment class. Results for this method, therefore, are only provided at the equipment class level. To calculate the AWC , first the e stimated potable water use and condenser water use per 100 pounds of ice are summed to provide a total water use per 100 pounds of ice. Factoring the total water use per 100 pounds of ice produced with the assum ed equipment utilization factor and representative maximum daily harvest rates yields a total daily water use figure for each equipment class. Multiplying the daily use values by 365 days in a year provides the total AWC

. For automatic commercial ice makers, the equation for AEC is:
AWC i 

### = ( PW i 

### + CW i 

### ) ÷ 100 × H i 

### × U i 

### × 365 Eq. 7.2
Where:
AWC i 

### = calculated total annual water co nsumption for equipment class i (g al /year) , PW i 

### = estimated potable w ater use for equipment class i (gal/100 lb ice),7-4 

### CW i 

### = estimated condenser water use for equipment class i (gal/100 lb ice), U

i 

### = assumed utilization for equipment class i ( percent of time producing and harvesting ice),

and H

i 

### = harvest rate for equipment class i (pounds of ice produced per 24 hours). Estimates for the potable water and condenser water use to produce 100 pounds of ice come from preliminary TSD c hapter 5 , Engineering Analysis , and are summarize d in Table 7.3.1

. Table 7.3.1 Total Annual Water Consumption

Equipment Class * Condenser Water Use gal/100 lb Condenser Water Use

gal/yr ** Potable Water Use gal/100 lb Potable Water Use

gal/yr ** Total Water Use gal/100 lb Total Water Use

gal/yr* IMH

- W

- Small

- B 156 85,410 22 12,045 178 97,455 IMH

- W

- Med

- B 148 229,585 21 32,576 169 262,161 IMH

- W

- Large

- B 137 375,038 20 54,750 157 429,788 IMH

- A

- Small

- B 0 0 22 12,045 22 12,045 IMH

- A

- Large

- B 0 0 20 29,200 20 29,200 RCU

- Small

- B 0 0 21 26,828 21 26,828 RCU

- Large

- B 0 0 20 54,750 20 54,750 SCU

- W

- Small

- B 165 33,124 29 5,822 194 38,946 SCU

- W

- Large

- B 165 90,338 28 15,330 193 105,668 SCU

- A

- Small

- B 0 0 30 6,023 30 6,023 SCU

- A

- Large

- B 0 0 26 9,490 26 9,490 IMH

- W

- Small

- C 110 160,600 12 17,520 122 178,120 IMH

- W

- Large

- C 110 200,750 12 21,900 122 222,650 IMH

- A

- Small

- C 0 0 12 6,789 12 6,789 IMH

- A

- Large

- C 0 0 12 21,900 12 21,900 RCU

- Small

- C 0 0 12 15,330 12 15,330 RCU

- Large

- C 0 0 12 32,850 12 32,850 SCU

- W

- Small

- C* * *

— — — — — — SCU

- W

- Large

- C 110 60,225 12 6,570 122 66,795 SCU

- A

- Small

- C 0 0 12 2,409 12 2,409 SCU

- A

- Large

- C 0 0 12 6,570 12 6,570 *See c hapter 5, Table 5.2.1 and 5.2.2 , for a description of these abbreviations

. **Total number is adjusted by the appropriate utilization factor. ***DOE was not able to identify any existing products of this equipment class in ice maker databases. Hence, this equipment class was not analyzed, directly or by extrapolation.