Ozone Washing Machines
Washing Machine: Ozone vs. Hot Water
Washing machines that use ozone in a solution and reduce hot water use by up to 90% while making clothes cleaner and longer lasting.
Item ID: 548
Process Loads & Appliances--Commercial and Residential Appliances
Technical Advisory Group: 2014 Commercial Building TAG (#9)
Average TAG Rating: 2.46 out of 5
TAG Ranking Date: 03/17/2014
TAG Rating Commentary:
- Ozone is highly reactive and toxic to humans - makes me wonder how it could be employed safely in a long lived, residential appliance with many moving parts and wear points.
- Good measure, may not be applicable to smaller commercial buildings
- There is the risk of leakage of pressurized ozone.
Ozone laundry systems have been named to the Federal Energy Management Program's Promising Technologies list. These laundry systems use ozone as the chemical cleaning agent. An ozone generator mounts to the wall behind or above a front or top loading washing machine and generates ozone by electrifying oxygen in the air. Ozone is produced in a three-step process: first, air is compressed in a compressor; then the compressed air passes through a pressure swing adsorption oxygen generator. Finally, the oxygen is fed into a corona discharge ozone generator. The ozone is then dissolved in cold supply water, resulting in a detergent-free cleaning system. Ozone chemically reacts with organics, resulting in fabric cleaning as well as disinfection, deodorizing, and sanitization. These systems save energy because ozone is effective at cold temperatures, eliminating the need to heat the wash water. Due to ozone's effectiveness as a cleaning agent, it is claimed that the washing machine can operate on shorter cycles with less rinses and thus less water. Ozone laundry systems thus have the potential to save detergent, bleach (as ozone is a powerful oxidizer), fabric softener, energy, and water, resulting in reduced operating costs. Ozone multi-load clothes washers, such as used in lodging, senior care, healthcare businesses and correctional facilities, have been shown to decrease hot water consumption associated with laundry uses by 91% (Source: FEMP, "Promising Technologies List").
Ozone generators can be installed as add-ons to existing laundry equipment with manufacturer's offering systems that operate on washers ranging from 35 to 400 lbs. Recent Consumer's Reports testing of residential ozone laundry systems, however, showed ozone was only a bit better than plain water at cleaning soils from fabrics (DiClerico, 2014).
Baseline Description: Energy use Per Hotel Room
Baseline Energy Use: 1066 kWh per year per Hotel Room
A typical long-term health facility laundry operation might use wash-water at a temperature of 180 deg F while an ozone system operates at a temperature range of approximately 50 to 60 deg F. An ozone laundry system was installed at a Best Western Hotel in Tempe, Az that had 158 rooms and three on-premise laundry washers. The ozone system reduced hot water costs by 86% and electricity costs by 32%.
The American Hotel and Lodging Association provides a summary of benefits due to installation of an ozone system at a 300 room hotel. The laundry room consists of three 125 pound commercial washers that process 12 loads per day on the average per machine (36 daily loads). Given a six day a week operating schedule, this equates to 4500 pounds per day or 1.47 million pounds per year. Elimination of the use of hot water results in a savings of 1,280,448 gallons per year (at 114 gallons saved per load). At 8.34 pounds per gallon, this equates to 10,678,936 pounds of water per year, and, assuming a temperature rise of 100 deg F, requires about 1067 MMBtu per year of thermal energy. Generally, this would be provided by natural gas, however, if it was to be supplied by electric resistance water heating, it would require about 312,890 kWh/year (assuming a 100% conversion efficiency). this is equivalent to 1,066 kWh per year per room or 244 kWh per thousand gallons of water heated.
Manufacturer's Energy Savings Claims:
Currently no data available.
Best Estimate of Energy Savings:
"Typical" Savings: 100%
Energy Savings Reliability: 3 - Limited Assessment
Use of cold water with the ozone systems results in a 100% decrease in hot water heating requirements.
Energy Use of Emerging Technology:
kWh per Hotel Room per year
Energy Use of an Emerging Technology is based upon the following algorithm.
Baseline Energy Use - (Baseline Energy Use * Best Estimate of Energy Savings (either Typical savings OR the high range of savings.))
Potential number of units replaced by this technology:
The American Hotel and Lodging Association reports 52,529 properties in the U.S. with a total of 4.9 million rooms. Average occupancy rate is 61.4% (2012 data). Prorating by population results in an estimate of 4% x 61.4% x 4.9 million = 120,344 occupied rooms in the Northwest on a daily basis. Overall, there are an estimated 196,000 rooms in the Northwest. While this estimate is overstated as it does not consider the percentage of laundry rooms with hot water heating due to use of natural gas, it is also underestimated as it does not consider laundry opportunities at laundromats, correctional facilities, health care, and senior assisted living housing.
Regional Technical Potential:
0.21 TWh per year
Regional Technical Potential of an Emerging Technology is calculated as follows:
Baseline Energy Use * Estimate of Energy Savings (either Typical savings OR the high range of savings) * Technical Potential (potential number of units replaced by the Emerging Technology)
Installed first cost per: Hotel Room
Emerging Technology Unit Cost (Equipment Only): $66.66
Emerging Technology Installation Cost (Labor, Disposal, Etc.): $6.66
Baseline Technology Unit Cost (Equipment Only): $0.01
The American Hotel and Lodging Association estimates a cost of $20,000 for an ozone laundry system that would serve a 300 room hotel. The labor cost to install the system is an additional $2,000. Equipment and installation costs are thus $66/room and $6.60/room, respectively.
The cost of a residential-scale pureWash laundry system is about $300 while a Wash-It system runs about $400 (DiClerico, 2014). These toaster oven sized ozone generators are easy to install as they mount to the wall behind or above any front-load or top-load washing machine. They are equipped with inlets and outlets that connect with the cold water line supplying the washing machine. A power adapter plugs into the nearest electrical outlet.
Simple payback, new construction (years): 0.7
Simple payback, retrofit (years): 0.8
Cost Effectiveness is calculated using baseline energy use, best estimate of typical energy savings, and first cost. It does not account for factors such as impacts on O&M costs (which could be significant if product life is greatly extended) or savings of non-electric fuels such as natural gas. Actual overall cost effectiveness could be significantly different based on these other factors.
Ozone laundry systems would be very cost-effective in locations where electrical energy is used to heat wash water in hotels, correctional facilities, senior citizen housing, health care facilities, or commercial laundromats.