The Water System

Tips & Tricks

The Water System
The water distribution system in a building is usually ignored as a potential energy conservation resource. It is a deceptively simple system, though, with many practical ways to optimize. These techniques can be divided into two general categories: reducing the use of water and reducing the heat lost from hot water piping.

• Inspect for leaks
  A simple way to reduce water usage is to be alert for leaks in pipes, fittings, pumps and gauges in mechanical rooms and at headers throughout the building. Faucets and other restroom fittings are also important locations to inspect for fluid loss. Swift repair of these water leaks will prevent collateral damage to wood surfaces and furnishings, ceiling tiles and electrical equipment. The savings will occur in the water bill and in a lower sewage disposal fee as well.
  
  Leaks that occur in closed systems can be even more expensive. Water circulating in the chilled water loop, the condenser water loop and the steam loop is usually chemically treated for corrosion and high hardness. Water lost from these systems loses valuable chemicals as well, which increases the treatment costs. In addition, the energy needed to heat or cool the circulating fluid will rise since a portion of the energy spent is lost with the leakage of hot or cold water.
  
  
• Reduce hot water storage temperature
  Whenever the water temperature at the point of use is too hot, copious quantities of cold water are needed to cool it to a satisfactory temperature. A slight reduction in hot water temperature will ensure it is delivered at the best temperature. Lowering the tank thermostat setting will also reduce the cost of keeping the water heated. A variation on this theme, called hot water reset, is practiced by large institutional users. A remote outside thermometer automatically increases the hot water supply temperature when the weather is warm. This can also be done by manually changing the setting at the beginning of the cooling season, then increasing it when the heating season begins.
  
  
• More efficient operation of cleaning equipment
  A good portion of the hot water used at an institutional building is devoted to washing dishes in the kitchen and washing clothes in the laundry. If the equipment used for these tasks does not have settings for different size loads then it is most efficient to operate them only when full. Use of an economizer cycle, if available, is another energy saver; for example, drip drying dishes naturally instead of with forced heat. Adjusting the settings to wash and rinse with the coldest practical water temperature will also save energy without sacrificing quality.
  
  
• Reduce volume of waste disposal methods
  Many commodes are now made with a smaller toilet flush tank to reduce the volume of water used with each cycle. The same principles have been applied in other appliances, for considerable savings. Such large users of water as clothes washers and dish washers benefit from water conserving practices, especially if the quantity of cleansers used are reduced so that less water is used in the rinse cycle.
  
  
• Inspect and repair damaged insulation systems
  Sagging or missing sections of insulation should be promptly attended, as they are not only an energy loser but may also indicate a leaking pipe in need of repair. If the insulation is worn because it covers a pipeline in a heavy use area the insulation should be replaced, then covered with a sheet metal sleeve to prevent future damage.
  
  
• Install time clocks on water heaters
  Most business offices are open during the daylight hours, Monday through Friday. Allowing for cleaning crews after hours, the time during which hot water is needed is perhaps sixty hours a week. The typical hot water heater is on all the time, 168 hours each week. A timer will greatly reduce this wasted energy. It can be set to turn on an hour of so before the beginning of the business day and still provide the same consistent service as though it were on constantly. Also, with extra down time, the heater will have a much longer useful life.
  
  
• Insulate hot water heater(s) and storage tank(s)
  Many utilities will provide water heater "blankets" at no cost. Others offer rebates to businesses and individuals who purchase high efficiency hot water heaters that have adequate insulation built into the unit. If the heater is located within the conditioned space, heat emanating from the unit will add to the load on the air conditioning equipment. If it is located outside - and is poorly insulated - much heat will be lost in the winter to the environs. In either case it is important to maximize insulation.
  
  
• Install flow restrictors at hot water faucets and shower heads
  This is another effective way to reduce water usage, while sacrificing little to convenience or necessity. To compliment such measures it is helpful to promulgate a general philosophy of water conservation, especially in the kitchen. People tend to think of water as an inexhaustible resource, not realizing the energy is saved by not wasting hot water.
  
  
• Consider increasing pipe insulation thickness
  Many older buildings were built at a time when energy was inexpensive. The hot water piping may not have been insulated at all, or it could be wrapped with a minimal thickness. A high quality product is available that is more efficient and durable. Pipe routed through unconditioned spaces such as the pipe basement or attic should not be without insulation.
  
  
• Consider instantaneous heaters at remote locations
  Several manufacturers offer small point of use instantaneous water heaters. If there are only a few locations in a building that require hotter water than the rest of the facility, these devices can help save energy - if the volume is low - by allowing the main hot water temperature to be reduced. This will reduce the thermal losses from the storage tank as well as from the loop piping.
  
  
• Install a separate water heater for the kitchen or laundry
  A sophisticated hot water system, in a hospital for example, will be designed to supply 180 degree F water to the kitchen and laundry and 120 degree F water everywhere else. Many buildings will simply supply the hotter water everywhere, at great waste - and sometimes great danger, from the scalding hot water.

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