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May 2011

The Hidden Cost of Water

With so much attention being paid to energy use, it's easy to overlook the cost of water--and there are many ways to save.

Written by Bob Bradbury, Energy Manager, Mammoth Mountain Ski Area | 0 comment

From your first cup of hot coffee in the morning to the last flush of the toilet at night, water is an essential part of our everyday lives, and few people give a thought to what it takes to make that happen. We are surrounded by uses of water that work for us every day, and they all have a cost.

Being in the mountains adds to that cost. If we have facilities higher up on the mountain, we usually have to pump domestic water up to where we need it. The higher you go, the higher the cost. We have a domestic water well located at 8,000 feet and we pump quite a lot of water from there in stages to our Top Gondola Station at just over 11,000 feet.

With many water systems, there is an evolution in their development. At the well at 8,000 feet, for example, we had a 60 hp booster pump that initially needed 60 hp. Over time the system evolved, but we still had a 60 hp pump using 60 hp. We replaced it with a high-efficiency 17 hp pump, and that is now doing the job at a fraction of the operating cost.

It takes vigilance to root out the hidden costs of water. For starters, all mechanical parts of the water system need to be checked at least monthly, and water regulators at least yearly. Water station building envelopes need to be inspected yearly for animal damage, settling, unused pipes, poor insulation, and other degradations, as these can cause heaters to be on more often, or pipes to freeze—driving up the hidden cost of water.

Some remedial steps are very simple. For example, we have a water station that is hard up against a million-gallon tank. I set the inside heater for the station at 40 degrees, as the tank water temp rarely goes below 42 degrees, and it keeps the room well above freezing. If the heater was set to 50 degrees, we would be, in effect, trying to heat the tank water, which would be a huge waste of energy.

A leaking distribution system can raise water usage and increase pumping and/or maintenance costs. We use water from our local water district for a couple of buildings in town and pay $2.07 per 1,000 gallons. If we used that number for the cost of water in the rest of our system, and we had some leaks in the pipes, it would not take long for that wastage to become a sizeable number.

Hospitality areas use lots of water, especially hot water. An older guest room showerhead can use up to six gallons of water a minute, and almost all of that is hot water. A low-flow shower head, which flows around two gallons per minute, will use 60 percent less hot water. For guests’ comfort, some manufacturers offer showerheads matched to your water pressure on each floor.

Any reduction in the guest room hot water flow rate will save money. At Mammoth, we use propane and pay as little as $.02 per gallon for hot water. At an average eight minutes per shower, two showers per day per room, with an annual occupancy rate of 70 percent—well, do the math. As an added advantage, during very high occupancy periods, we are less likely to run out of hot water, a very large no-no that can cost you a lot of discounts.

Showers aren’t the only place to cut guests’ water use. Use aerators on room sink faucets so they will use less water. Leaky faucets, especially hot water, should be repaired right away. Low-flow toilets will use less water, too.

Many hospitality operations have a laundry connected with them, and that’s another place for conservation. It is a waste of energy (and money) to use water that’s hotter than needed for the laundry detergent. Other energy-saving steps: use low-temperature detergents and a water softener.

Then you can get more creative: Preheat the water going to the laundry’s hot water heaters with warm waste water from the washing machines. You can boost the temperature of the incoming water by 20 degrees and reduce the hot water costs by 25 percent.

Even wastewater can have its costs. Some municipal waste water systems measure the outflow on large commercial users and charge by the gallon. The more you produce, the more you pay.

One obvious savings: Waterless urinals. They can save many thousands of gallons of water; at Mammoth we have installed them in many locations. Some designs have cleaning and maintenance issues, but the best units minimize them. Low-flow toilets are also becoming more efficient and maintenance-friendly. Auto faucets and flush devices can also lower the use of water.

Some resorts have bigger water issues. For example, pools and spas are generally outside, and a pool/spa is one large heat exchanger. If it is cold outside a lot of heat is released to the air. When not in use, especially at night, put a cover on outside pools to reduce heat loss.

On the other hand, if you have an enclosed pool/spa area, it gets quite humid and warm inside. Typically, resorts use an exhaust system to improve air quality. In that case, use an air-to-air heat exchanger to use heat from the exhausted air to heat the dry incoming air and save a lot of money.

The type of heater used in the pool or spa can make a real difference, too. Older atmospheric gas water heaters can be as little as 62 percent efficient; newer ones can be up to 97 percent efficient. This is a huge difference, though the initial cost difference can be large as well.

There can be hidden costs during summer months, too. Irrigation systems are typically hooked up to the nearest domestic water system. This causes increased pumping costs. If you have your own domestic water system and have to treat that water, that further drives up costs. One solution: install smart controllers that look at temperatures, humidity, moisture content, and recent precipitation and then customize sprinkler times. Even better—if you have a stream nearby, even if it is seasonal, and have at least 40 feet of head, you may be able to use that to supply the irrigation system, at pretty much no cost.

Kitchens and bars use a lot of water year-round. Making ice in a cold climate is kind of a redundant idea, and is rather energy intensive to boot. Then, we often compound the problem by placing the ice machines in the kitchen area, which usually has higher ambient temperatures. And that further drives up the cost of making ice.

And how do you dispose of ice you no longer need? Ice is used for a wide range of food service activities, and at the end of the day, some kitchens put it in a sink and melt it with hot water. So it costs a lot to make, and then costs a lot more to melt.

The kitchen, in fact, is a great place to root out hidden water costs. Kitchen staff are usually poor at water conservation: it’s not uncommon to see sinks overflowing with hot water. Then when thawing frozen products, the cold water is turned on high. Leaking faucets, especially hot water, are common, too.

Some fixes are obvious, but others require a bit of out-of-the-box thinking. For example, it’s a good idea to install an enzyme injector before kitchen grease traps. You cut down on grease buildup in the plumbing, you cut disposal costs, and eliminate odor. The same idea works well in sewer lift stations, too, and in locations with septic systems—it promotes the biological process, which cuts the need to pump it as often, and you have fewer backups. For the worst problem areas, we use a product that has both aerobic and anaerobic bacteria to keep the water flowing smoothly.

If there is a dedicated steam boiler, you use it for steam kettles, steam ovens, domestic hot water, high temperature dishwashers, and sometimes building heat. If any of the steam appliances dump spent steam into the drain, that is a waste of energy. Two steam kettles dumping spent steam into the drain will cost up to $1,500 a season.

Instead, recycle the hot water from the steam appliance steam traps back to the condensate tank and reuse it in the boiler. That way, you do not have to heat fresh, 45-degree water to 180 degrees in the boiler—you’re starting with water that’s already a lot warmer than that.

There’s another issue with bringing all fresh water into the condensate tank and the boiler: as it turns to steam it leaves any dissolved solids, such as calcium, in the boiler, and that will coat the water tubes over time. That coating acts as insulation, and the tubes don’t absorb as much of the burner heat—which goes up the flue stack. A water softener installed on the makeup supply will cut down on, but not eliminate, the calcium and other chemicals in the water.

Larger fire tube-type boilers using fuel oil should be cleaned at least twice a year to remove soot buildup on the tubes; the soot acts as insulation and reduces heat transfer. Soot buildup is easy to test for in larger tube-type modulating boilers. Run the boiler at full fire just after you clean the tubes, and check the exhaust temperature. Then, once a month or so, run at full fire and if the flue temperature is more than 7 degrees higher, it’s time again to clean the tubes.

Periodic burner tuneups for larger modulating boilers are also a must, as they can go out of adjustment. An older burner probably has worn-out linkages and damper bushings. If so, it won’t burn properly throughout the range, and a newer, more efficient burner may be in order.

Since an inefficient boiler adds to the cost of water, in fire tube boilers, consider installing tube turbulators. They swirl the hot flue gases to the outside of the last pass tubes, and the boiler will absorb more heat. Barometric dampers will almost eliminate convection draft of heat out of the boiler when it is off. Between these two steps, the boiler efficiency can be increased by at least 14 percent. Not watching the boiler chemical levels can drive up the maintenance costs, too. Do not wait until there is a problem to do maintenance.

Conventional gas hot water heaters with the heat exchange tube in the middle are not very efficient, and if they don’t have automatic flue dampers, they are really inefficient.

Upgrading to a high-efficiency heater is cost-effective, but does require a bit more maintenance. For smaller applications, on-demand gas hot waters heaters can lower your overall energy use by 35 percent over a conventional gas hot water heater.

Hydronic heating systems need attention, also. Some systems use antifreeze; be sure to check the antifreeze protection, corrosion inhibitor, and ph levels at least twice a year. If they are all low and not treated, they will cause increased maintenance and replacement costs. These systems are already up to 7 percent less efficient, simply because antifreeze does not carry heat as well as water.

On systems that use straight water, check the corrosion inhibitor twice a year. If the corrosion inhibitor level is consistently low, you probably have a leak, which increases your water costs. If you have corrosion in your system you have big problems.

At least once a year, clean the heater’s heat exchangers. In a hospitality guest room, if the heat exchanger is dirty, it will not heat the room properly, and you give the guest a bad experience. Larger hydronic boilers need the same maintenance as steam boilers.

Water conservation is a valuable practice. Water that goes down the drain in the local sewer system has to be treated, which uses energy and usually involves adding chemicals. Reducing the amount of waste water cuts the amount of domestic fresh water needed, energy costs, CO2 footprint, and helps delay capital expansions to the water system.

Because of that, rebates are often available from water districts for water reduction devices. Most electric and natural gas providers also offer rebates and grants to offset the cost of equipment and pump upgrades, augmenting the money you save. Ultimately, lowering the hidden cost of water is a win-win: it’s good for both your bottom line and the environment.