Commercial Food Service Introduction
Commercial food service represents one of the larger water using sectors in the non-residential category. Consider this.....thousands of meals prepared and hundreds of thousands of pieces of dishware washed every year in just a single restaurant establishment! Water use in food service is especially important because the high volume applications in those facilities are generally using hot water. As such, the energy required to heat that water can be significant and the energy utilities recognize this. The reduction of hot water consumption is therefore of much interest to both the energy utilities and the water providers.
Escalating energy costs in the past few years resulted in food service operators focusing more attention on their utility bills and seeking ways to reduce costs. Hearing this, the manufacturers of restaurant equipment and fittings have responded with research, development, and production of new and very efficient products.
Overview of Savings Opportunities
Fisher, D (2006) Energy and Water Savings in Commercial Food Service - presentation - This presentation provides a comprehensive overview of energy and water savings opportunities in the food service sector.
Commercial Pre-Rinse Spray Valves (PRSVs)
Commercial pre-rinse spray valves are part of the pre-rinse operation in the dish room of a typical food service operation. They are used to remove the large particles of food from dishware and utensils prior to loading them in the commercial dishwasher.
Almost every commercial kitchen in the country uses one or more pre-rinse spray valves, and in fact, many facilities use two or three. A conservative estimate of (hot water) pre-rinse spray valves installed in dish rooms in North America is 1 million units.
Most standard-flow spray valves flow at 3.0-gallons per minute (gpm) or more (11-litres per minute or more) of hot water and are used, on average, 1 to 4 hours per day. The flow rate of water and energy-efficient models is only 1.6-gpm (6.0-Lpm) or less. These efficient units can save the average small to medium food service operator as much as 150 gallons of hot water per day. The efficient models have an added benefit in that they are equally effective in cleaning the dishes as the non-efficient units. Replacement spray valves generally cost less than $50 each and have a useful life averaging about five years.
The California Urban Water Conservation Council’s (CUWCC) Phase 1 Rinse & Save Program began in 2002 and was directed at replacing about 17,000 of the 102,000 hot water PRSVs in the state. It was followed by Phases 2 and 3, ending in 2006 having replaced 41,000 PRSVs statewide. It's full-service direct installation approach of is being copied in a number of locations elsewhere in North America, yielding significant energy and water savings benefits for food service operators. For details on the CUWCC program, the PRSV specification used in that program, a list of qualifying PRSVs, and savings data, go to the program website. In addition, the CUWCC 2004 PBMP Report contains a section on PRSVs. You can also download reports by the Program’s Evaluation, Measurement, and Verification (EM&V) consultant here:
SBW (2004) Evaluation Measurement and Verification Report for the CUWCC Pre-Rinse Spray Head Distribution Program
SBW (2007) Impact and Process Evaluation Final Report for the CUWCC Pre-Rinse Spray Valve Program
Reports on similar programs and field trials from other regions provide more information on the water savings achieved and the difficulties encountered.
1) Waterloo Pre-Rinse Spray Valve Pilot Study Report
A Pilot Study undertaken by the Regional Municipality of Waterloo, Ontario measured water use "before" and "after" PRSV retrofits in 10 different food service operations in the region. Veritec Consulting, Inc. measured water use at each installation using datalogged paddle-type flow switches and pressure loggers. Savings on a per hour of use basis exceeded by about 30 percent that found in the Council's Rinse and Save Phase 1 Program as documented in the SBW Phase 1 Report.
Veritec (2005) Region of Waterloo Pre-Rinse Spray Valve Pilot Study
2) Calgary Pilot Study
A second study was performed in Calgary, Alberta, and also involved "before" and "after" measurements at 10 installation locations.
Veritec (2005) City of Calgary Pre Rinse Spray Valve Study
3) Puget Sound Comparison
An comparative analysis of the Rinse & Save Program results with those of similar programs in the Puget Sound region of Washington State provides additional information
Tso, B and J Koeller (2005) Pre-Rinse Spray Valve Programs - How Are They Really Doing
4) FSTC Cost Calculator
The FSTC has developed a simple cost calculator that yields water and energy use for the "old" and "new" PRSV that is installed in food service. Find it here:
5) EPA WaterSense PRSV Study
The EPA researched the impact of new high-efficiency PRSV's from the perspectives of water savings, effectiveness, and user satisfaction. The results were published in 2011 and are available here.
EPA WaterSense (2011) Pre Rinse Spray Valves Field Study Report
Commercial dishwashers and PRSVs in the typical restaurant dish room together represent the largest consumer of water in such establishments. While much has been done by water providers to reduce water use through efficient PRSVs, the efficiencies achieved by dishwasher manufacturers have been largely without the support of the water industry. Instead, since water and energy are linked within the commercial dishwasher, the demands for energy efficiency have resulted in manufacturers developing and marketing extremely water-efficient models. For example, in the late 1990s, NSF International (the listing agency for such machines) showed that the most efficient dishwashers used 1.2 gallons of water per (20-in by 20-in) rack. Today, machines are available at well below 1.0-gallons per rack.
Koeller, J. and Hoffman, B. (2010) A Report on Potential Best Management Practices - Commercial Dishwashers (PDF)
Commercial Dishwashers (2006) Water Use and Specifications (Excel)
The FSTC conducted a field study to determine the water and energy use profiles of both boiler-based and boilerless (connectionless) food steamers with funding provided by the Metropolitan Water District of Southern California and East Bay Municipal Utility District, Oakland, California, The steamers in multiple food service operations were measured for water and energy use. The study confirmed that the relatively new connectionless technology yields significant water use reductions in food service (more than 80%), due largely to the elimination of condensate-cooling water. The findings in this report are serving as a basis for large incentives directed at the food service industry with the goal to eliminate boiler-based steamers wherever possible, and replace them with the connectionless technology.
The water efficiency standard has been set at less than 2 gallons per pan per hour, at full operational capacity (pan size is standardized in the food service industry). There are a few facilities (such as "made-to-order" restaurants) that require supercharged steam to cook the food more quickly; required a steam supply from a central boiler. In these rare cases, the water efficiciency standard is set at 5 gallons/pan/hour; still achieving a significant water savings over traditional boiler connected steamers sometimes using more than 20 gallons/pan/hour.
Special Note of Caution to Water Providers:Some manufacturers have adopted terms like "boilerless" or "connectionless" as a marketing tool without regard for the water efficiency of the equipment. As such, not all food steamers currently labeled as "connectionless" or "boilerless" are, in fact, water-efficient. If your water authority or municipality is considering implementing an incentive program for steamers, be sure to consult with the Food Service Technology Center (David Zabrowski - 925-866-5614) before defining or "listing" the equipment to be included.
Download the complete FSTC field study report on steamers here.
Karas, A et al (2005) Evaluating the Water Savings Potential of Commercial “Connectionless” Food Steamers
The Metropolitan Water District (MWD), working with test results and other information from the FSTC, has established a list of connectionless steamers that qualify for its $485 per compartment rebate (through its "Save Water - Save A Buck" Program). Each of the steamers on this list are deemed water-efficient by virtue of the fact that their consumption rate does not exceed 2 gallons per hour.
Most of the machines on the MWD list are also energy-efficient. As such, the energy utilities in parts of North America also offer rebates for their purchase. Check the FSTC's official listing of qualified energy-efficient steamers here.
Note: The above lists are provided as a service of the AWE and the FSTC. There is no assurance that the water or energy efficiency programs will use this list as a basis for establishing or funding rebates. You are advised to contact your local utility to determine exactly what equipment is rebated.
The water and energy efficiency of commercial ice-makers both vary significantly among the many equipment models on the market. In general, however, water-cooled machines are not the preferred option. Air-cooled machines are more water-efficient, energy-efficient and cost-effective for the owner. Recent research that encompasses all of the energy (direct energy and embedded energy) required by equivalent air- and water-cooled machines clearly indicates that air-cooled machines are the best choice for efficiency. (Note: The Hoffman life-cycle cost calculator linked below shows that when all costs are taken into consideration, water-cooled machines are never the environmentally preferred or most economical option.)
Commercial ice makers use much more water than just the water contained in the ice itself. A perfectly water efficient ice maker would use only 12 gallons (8.33 pounds per gallon) of water to produce 100 pounds of ice. The ice makers use additional water to rinse mineral deposits off the ice (to clarify the ise) and freezing stations (preventing scale build-up); and some machines use water to cool the compressor and refrigerant condensation coils. The most wasteful ice makers use more than 150 gallons (1,250 pounds of water) of water to make 100 pounds of ice. As a initial benchmark, water efficiency standards require ice machines use 25 gallons or less to make 100 pounds of ice (50% efficiency); this benchmark is expected to become more stringent as ice maker technology improves and consumers dismiss the preference for crystal clear ice cubes.
1. Ice Maker Field Study
A ground-breaking field study of commercial ice machines was undertaken by the FSTC on behalf of four financial sponsors: East Bay MUD, Seattle Public Utilities, Eugene Water & Electric Board, and Pacific Gas & Electric. This field study was directed at measuring "real world" water and energy consumption of installed air-cooled and water-cooled equipment at a selected number of field locations. The full study report, released in late 2007, may be downloaded here:
FSTC (2007) A Field Study to Characterize Water and Energy Use of Commercial Ice Machines
2. Spreadsheet Calculators of Machine Life Cycle Cost
Bill Hoffman (City of Austin, TX) has kindly allowed us to post his excellent life cycle cost calculator for commercial ice machines. This spreadsheet permits you to compare equivalent air-cooled and water-cooled machines to determine the cost to the owner/operator over the expected life of the machine. In order to complete the analysis, you will need to: (1) obtain information from the American Refrigeration Institute database, (2) identify where the machine is to be located (in air conditioned or un-air conditioned space), (3) identify the number of days per year the machine will operate, and (4) identify the cost for local utilities (water, wastewater, electricity).
Hoffman, B (2007) Commercial Ice Machine Life-cycle Cost Calculator - Excel spreadsheet file.
The FSTC has also developed a calculator that provides annual and life-cycle costs. Access it here.
3. Research on Ice-Makers
A number of other documents by various organizations could prove helpful in understanding the products in the marketplace and their efficiencies.
Ferstrom, G (2004) Analysis of Standards Options For Commercial Packaged Refrigerators, Freezers, Refrigerator-Freezers and Ice Makers
FSTC (2004) Ice Maker Efficiency Comparison
CEE Ice-Makers Specification
Koeller, J. et al. (2008) PBMP - Commercial Ice Machines
Very Special Thanks to the Food Service Technology Center
The water efficiency community is extremely grateful for the attention and resources provided by the Pacific Gas & Electric (PG&E) Food Service Technology Center (FSTC) in San Ramon, California. The FSTC studies and tests water-using products and seeks out opportunities for energy and water use efficiency. The experience of the FSTC in the food service industry has been of significant value to the water efficiency practitioners in California and elsewhere. In particular, the FSTC was the genesis of the highly successful Pre-Rinse Spray Valve programs in California and across North America. In addition, they have provided valuable efficiency information on food steamers and commercial ice-makers.
NOTE: The FSTC programs are funded by California utility customers and administered by Pacific Gas and Electric Company under the auspices of the California Public Utilities Commission. The FSTC's very comprehensive website can be accessed at www.fishnick.com