water management systems

In addition to the fuel for heating & electric power as the energy sources, water is the third primary energy source in hotels. Hotels are very dependent on safe, potable water supply & a sanitary drainage network. Nowadays, water has become a very important energy source.

Sources of water

The sources of water are:
• Surface sources, e.g. rivers, lakes, ponds, etc.
• Ground water taken out by water pumps, tubewells, wells.etc.
• Recycled water e.g. treated waste water used in hotels for washing & other uses than drinking or cooking.
The water from the above sources may be obtained by the public works department or by self-drilling underground till the water table & tapping the water source underground. Generally, surface
Water are found to be more potable than ground water if the bore-well has not been drilled till the water table beneath the earth.

The primary sources of fresh water are rivers, lakes, & ground water. If rivers & lakes become polluted, our water resources become seriously restricted because more water must be extracted from the ground.   This presents a potential problem, which could limit growth of hotel in some areas. The water table in many areas is falling, forcing public works department to drill deeper wells to obtain increasing amounts of water. In effect, we are using ground water faster than nature can replenish it.
                     Water may have to be treated to make it potable, that is, safe for human consumption. The treatment process depends on the number & types of water impurities & the rate at which potable water is desired. This can be a costly process. This distribution network supplies water to where it is needed. The drainage network collects unwanted or waste water & delivers it to a treatment plant, where it can be treated, thus preparing it for recycling.

Water Hardness & Removal

One water condition is extremely variable around the would –water hardness. It can cause a number of problems in the hotels.
Water hardness is caused by calcium & magnesium salts, which are normally present in potable water. These are called hard salts because of two factors.
1. When hard water is heated, salts will frequently precipitate out causing a lime build up within pipes & around plumbing fixtures or deposits on items being washed.
2. When water containing these salts is mixed with natural soap & some synthetic cleansers, the salts combine with cleanser chemicals & precipitate into & within the products being washed. The resulting mixture is called soap curd, a sticky substance that is difficult to remove from washed products.
In most cleaning processes, an overabundance of cleansing agents must be used to reduce or eliminate the effects of hard water salts. This makes dish washing & laundering costly. The energy requirements of housekeeping tasks are increased when hard water is present since acidic & abrasive cleansers are required to remove lime build up. The life of linens laundered in hard water is significantly reduced. Linens, dishes,& cooking utensils washed in hard water will eventually become discoloured, developing either a yellow or a brown cast.
     Calcium salt deposits are harmful to hot- water heaters, boilers & heat exchangers. The precipitate serves as a heat insulator & lowers the operating efficiency of the unit.

Therefore, water must be softened for the above purpose. Water is treated with chemicals that combine with hard-water salts to form chemical buffers so that salts will not precipitate from water. The most frequently used hard water salt eliminators are tank filled with a synthetic chemical resin called zeolite. Zeolite has an affinity for hard water salts & collects them on its surface. Hard water salts removed from water are replaced with a soft salt, such as sodium. Sodium salt is free- rinsing & does not create hard-water salt problem. The zeolite resin eventually becomes saturated with hard-water salts & must be regenerated. Regeneration is a process that over saturates the zeolite with a soft water mixture, brine. The soft salt replaces hard salts on zeolite surfaces. Common salt, sodium chloride, is used for regeneration. The zeolite process is practical & feasible because of current low cost of sodium chloride & water.
    There are two additional salt compounds that can be used to regenerate water softeners. A low sodium salt has to be processed & should be used because of the harmful effects of sodium on the environment. Potassium chloride can also be used as a sodium chloride substitute for water softeners. Potassium replaces sodium in the soft water .As potassium is required in some human diets; this may be an ideal substitute in some cases. Potassium chloride has a higher cost than sodium chloride.
  Many hospitality industry establishments soften only hot water. This is a questionable practice since mixing soft & hard water results in hard water with all its related problems. The softening of hot water may be practical in a foodservice establishment when soft water is not usually mixed with hard cold water.

Water Supply

From Mains 

This is the water supply from the public works departments, either from the water reservoirs or deep walls. A water main is buried underground just outside the building water supply line. The main pipe of the building water pipe line is fixed to the water main, with a gate valve & water meter attached to it. The water meter works on the principle of pressure & time period the water passes through it, for the reading. Water obtained from the utility is usually been treated to meet a local standard. Additional water treatment to remove elements that could have undesirable effects on building equipments & services (such as dish washing, laundry, & swimming pools) could be necessary for different properties.

From Wells

If the facility of mains supply is not there, water may be pumped from a deep well, drilled on land use area. The pump when pulls the water from underground, mechanical energy is converted to water pressure.
For the pumping of water, different types of water pumps are available:
1. Jet Pump: The initial cost of this pump is low, but operating energy requirements is generally high. Pumping efficiency varies from 15 to 45 percent. The water table must be within 100 feet (30.5 meters) of the ground surface.
2. Centrifugal Pump: Submersible pumps & turbine pumps. If the centrifugal pumps are located in a well & the motor is positioned at ground level, it is called turbine pumps & if motor is also positioned in the well with multistage impellers, it is called a submersible pump. Turbine & submersible pumps are very efficient in pumping large quantities of water from a well. These pumps are fairly efficient, reaching 80 percent in some cases & use the principle of centrifugal force to force the water up from underground.
3. Reciprocating pumps. This provides a large life potential. Its efficiency is relatively high, reaching 90 percent in some cases. It has a piston that moves back & forth in a cylinder & it can be driven by an electric motor.

Calculation of water requirements:

The total water requirement is calculated from the previous energy database available of your own property & other existing hotels in the area.
By the available database, the assumption as per the following parameters is done,
1. Water consumption per occupied guest room at night.
2. Water consumption per guest room per year.
3. Water consumption per square foot per year.
4. Water consumption per cover in the food service outlets & room service.
The estimates for a hotel are done per guest room in the property. Variables for these requirements will be laundering requirements, sewage requirements ground irrigation swimming pools & direct consumption that is assumed not returned to sewage lines, e.g. drinking water, water for cooking etc. Further, the water requirements is calculated on the basis of ratio of water consumption between sewage & rest all other consumption as discussed.

Water Distribution System

There are two ways of water distribution in the building as per different pressure available in the supple. They are up feed & down feed system.

Up Feed System

When the water supply pressure is adequate to force water throughout a building with floors, the maximum number of floors that can be serviced with this system depends on the water pressure at the main, fixture pressure requirements, piping resistance & the height of the building. When water pressure is inadequate either in main or deep well pump, circulating pump is installed in the supply line to raise the water pressure to overcome piping resistance or building height.
This system is frequently used on hot water lines to provide an almost zero wait time for hot-water supply.

Down feed System

Water is forced or pumped to storage tank located above the highest fixture level. When water is required, it flows by gravity from storage tank to the fixture. For hot water supply in tall buildings, down feed system is fitted with circulating pumps in the line to ensure adequate amounts of hot water at each fixture.
Combination systems: The up feed system is used for lower building levels & the down feed system for upper building levels. This system is effective distribution system for multiple floor buildings because water main supply pressure is utilized to the fullest extent & pumps & an upper water storages tank provides additional pressure for the upper levels.

Piping

Piping includes pipes, pipe fittings, plumbing fixtures and valves.
Pipes
Pipes are identified as follows: main service pipe which supplies water to the building; fixture branch pipes which supply water to single fixtures; and distribution (branch) pipes which supply water to fixture branches.
The common piping materials are plastic pipes, galvanized steel, brass and copper. Plastic pipes are the most required materials these days in plumbing system. Several grades of plastics are available, such as acrylonitrile-butadiene- styrene (ABS) - plumbing drainage system, polybutylene (PB) - cold and hot water and gas, polyethylene (PE) - cold water, polyvinyl chloride (PVC) -cold water and chlorinated polyvinyl chloride (CPVC) - cold and hot water pipes that do not exceed 180°F (82.2°C).
Pipefittings
Various fittings are available that allow piping turns e.g. bend; piping connections e.g. nipple, joint union; and the connection of piping fixtures, controls, and other devices. These fittings are either threaded or compression-type fittings, which include soldered connections for copper and solvent cement for plastic. Threaded fittings and connections are much stronger than compression fittings; hence, they are generally recommended for high-rise buildings.
Valves
Valves control the flow of water.
Gate valves are used as on-off valves. They are operated in either completely closed or opened positions. Their resistance to water flow is minimal. These are used as shutoff valves on water mains.
Angle and globe valves are used for variable water flow. They have a high resistance to water flow when partially opened; thus they restrict water flow. When completely opened, they have moderate resistance. These are used in bathtubs, showers and sink.
Check valves allow water to flow only one way, have minimal resistance and act as shutoff valves for reserved water flow.
Needle valves are key valves used to control the flow of cooking gas. They are generally found on gas equipment and provide very accurate controls.

Plumbing fixtures
The minimum required the maximum number of people that may occupy a room at any given time determines number of plumbing fixtures.
Plumbing fixtures are grouped into various categories. One group includes toilets and urinals. These fixtures require large quantities of water flushed.
Another group of fixtures allows the occupants to use water for washing or for equipment operation. These include lavatories (for washing face and hands); showers; sinks of all types, such as laundry trays and sinks, vegetable preparation sinks, and pot and pan washing sinks; dishwashing equipments; swimming pools.

WATER SUPPLY MAINTENANCE

The most common water supply maintenance problems are dripping faucets, piping vibration noise, and piping expansion noise. These are usually reported by guests or by an alert housekeeping crew or are found during management inspection of the property. In areas where labor costs are high, it costs more to repair these items than the resulting energy savings. There is no set cycle, other than the approximate age of the plumbing network, of such major piping failures as broken pipes.

LEAKING VALVES AND PIPING

Dripping faucets increase housekeeping costs and maybe annoying to guests. If one additional minute (60 additional seconds) is required to clean fixtures with dripping faucets, and if additional cleaning chemical requirements are considered, the additional 3 man-minutes (180 man-seconds) per guest room (lavatory, toilet, and bathtub-shower combination) can become expensive, amounting to about $1 per guest room per week.
The corrective-maintenance procedure is simple. A valve seat washer usually has to be replaced. The need to replace a seat washer depends on its use, its age, the water temperature, its materials of construction, and the chemicals in the water supply.
Water leaks that develop at piping connections are difficult to control. . They must be visible and exposed, or large water losses may occur (since the effects of water damage must be observed before you know there is a leak). This is why all connections should be designed so that there are visible inspection points for periodic checks. The building preventive-maintenance program should inspect these points every 12 to 24 months.

PLUMBING VIBRATION NOISE

Plumbing vibrations can cause noise that is transmitted throughout the building. Hot-water piping can cause a noise problem. When pipes are heated by hot water, they expand, and rapid piping expansion can generate noise. Reduced hot-water temperatures and adequate piping insulation will solve this problem.

  PIPING-EXPANSION PROBLEMS

Piping expansion can also cause pipes and connection points to separate. Provisions must be made to reduce this problem. While copper and plastic pipe are recommended in most new installations, these materials have the greatest expansion coefficients. One solution is to use piping materials that have low coefficients of expansion (pipes other than' copper or plastic). Another solution is to install expansion devices, such as piping loops and expansion joints. These devices do not prevent materials from expanding, but they allow piping to expand at controlled points and eliminate undesirable expansion noises.