Water conservation

Description

SUMMARY

What is disclosed is the idea and method for utilizing wasted water that is, a by product of the chillers and air conditioners, especially in humid regions of the planet to provide water for drinking and other potable water applications. This water is generated at the location of the air inlet chiller units of central air conditioning units that are placed on the roofs of high rises and on central raised locations. Today this condensed water is a problem and is discarded down the drain. The placement and location of central AC units, on top of buildings and industrial complexes allow water to be collected and supplied by gravity, to the usage area. By providing a collection tank with filtration and preferably UV irradiation capability, the collected water can be made potable with no further treatment. Such a scheme will reduce the usage of piped water in the cities.

2. Field of Invention

This invention relates to the conservation and utilization of scarce resources, in this case water, in humid regions of the world and high humidity periods.

2. Background and Prior art

Water is becoming a scarce commodity in most urban areas. Today a large number of cities have water rationing for the people living within the area. The growth of population and the increased need for water for agriculture with remote storage of water has tended to deplete the ground water resources in a number of areas leading to scarcity of usable water for the population. It has been projected that drinking water shortage will become acute in many regions of the world, both developed and underdeveloped by the end of the 21^st century. Currently there are in effect conservation methods in many places across the world where the rain water collection is mandatory for supplementing the water supplied by the city water supply schemes. It is also being recommended that a sump for percolation for underground water be used and open areas and ponds be built to collect the run off from rains as building booms start to limit open ground available for water to seep under ground and replenish the ground water supply. In other places the water is already scarce and it has to be brought in by trucks to fill underground tanks. This water is then pumped up and stored in water tanks on top of buildings for use by tenants. Even though conservation is happening it is not yet sufficient to over come the future scarcity.

Every drop of available water need to be conserved if future scarcity problems and cost of water have to be reduced.

What are the major issues facing water supply?

• • 1. Large population growth causing need for potable and usable water.
  • 2. Increased need for water for industrial and agricultural uses.
  • 3. Extended growth of cities where the water supply distribution system is stressed.
  • 4. The cutting down of trees and reduction in forests have reduced rain fall in lots of areas.
  • 5. It has also resulted in immediate run off of excess water to streams without allowing for percolation to replenish ground water.
  • 6. The reduced re-supply of the ground water, due to filling of ponds and water collection areas for buildings and agriculture, resulting in depletion of the ground water supply to dangerously low levels in many areas of the world.
  • 7. Building of dams and diverting of streams has not also helped the re-supply of needed ground water resources.
  • 8. In many cities the lack of percolation areas around homes due to use of cement around buildings have resulted in reduced percolation.

The solutions suggested and are being implemented include:

• • 1. Mandatory collection and use of rain water is cities to supplement water supply by the city.
  • 2. Provision of areas for collection and percolation of rain run off within built areas as part of the city planning process.
  • 3. Use of recovered waste water from sewage for operations such as gardening and car washing.
  • 4. Reduce removal of trees and conservation green land.

On a larger scale the solution suggested seem to be:

• • 5. There are proposals to use de-salination of sea water in many parts of the world but this is a capital and power hungry process and may be difficult for under developed and developing nations to implement on the scale that is needed to meet the growing needs of the population.

In most urban areas the scarcity of land and the land cost is pushing the height of buildings. Any big residential, office or industrial building today is centrally air conditioned.

FIG. 1 is the representation of a typical central air conditioning scheme for high rise apartments, offices and factories of today. The air intake (14) from outside is mixed with part of the air re-circulated from the building (18) to reduce having to expend energy in completely cooling down to the room air supply(19). This mixed warm humid air (15) is cooled in the cooling unit (4) and the cold air that comes out (19) forms the supply to the rooms. The air that is coming from outside in a humid climate or region when mixed and cooled will get super saturated with moisture (temperatures reaching below dewpoint) and part of this precipitates typically on the cold surfaces of the pipes and fins in the cooling unit. Today this precipitated moisture is drained out to waste and discarded. In most cases the moisture precipitation is not completed before the air is send to the out let to be passed into the living space. So there is high humidity and chance for mold growth in the living space. The high humidity of the incoming cold air is not very comfortable, with over 80% RH. Typically a lower relative humidity of about 40 to 60% is considered optimum for living and working. It also helps reduce mold growth and damage to furniture and fittings. Today this optimization of humidity is difficult and costly.

What is Proposed:

What is being proposed is an additional step in the conservation of water, but which may be able to provide potable water to some of the population in the urban areas, especially in humid regions and/or humid seasons. What is proposed also is a way to reduce the high humidity of the room air by allowing more complete precipitation of moisture from the incoming mixed cooled air.

By ensuring that the excess moisture in the air is removed by precipitation as usable water, prior to mixing and re-circulation, the problem of over humidifying and also mold growth can be reduced. This is a positive add on, to the availability of the almost pure precipitated water. By allowing the air to be super saturated by cooling and then allowing as much of the moisture to precipitate prior to mixing with re-circulated air a more comfortable drier atmosphere is created in the living and work areas which will be more comfortable for the people and reduce the problems of fungus growth due to high humidity. The collected water can be purified and used for supplementing the water supply.

The advantages of such a scheme are:

• • 1. The excess water after cooling from the in let air is precipitated and collected for use.
  • 2. This water can be filtered and purified by UV, if necessary and made potable and made available for drinking.
  • 3. If the cooling filter is placed on top of buildings, the collected water can be supplied to the building by gravity feed eliminating the need for additional power for pumps etc.
  • 4. This collected water can be used efficiently to reduce the high cost of drinking water supplied by the city and hence these units can provide high ROI.
  • 5. The removal of the water content from the saturated inlet air will reduce the humidity of the air and make it more suitable for use in living and working space.
  • 6. The lower humidity will reduce damage to the internal structures and coverings in the space.
  • 7. It will reduce the fungal growth most often seen in air conditioned spaces in humid areas.

DESCRIPTION OF FIGURES

FIG. 1: Typical Air conditioning unit

FIG. 2: Proposed Super cooling AC unit with precipitation unit and water collection unit attached.

Explanation of Numbering and lettering in the figures for typical implementation For FIG. 1 and FIG. 2

• • 1. Compressor unit
  • 2. Heat exchanger for removal of heat
  • 3. Piping for compressed refrigerant (similar to HCFCs or Freon)
  • 4. Expander chamber and cooling unit
  • 5. Air intake vent
  • 6. Intermediate air vent between the cooling unit and precipitator unit
  • 7. Air outlet vent
  • 8. Precipitation chamber (unit) with precipitation vanes
  • 9. Piping for cold expanded refrigerant.
  • 10. Water drain from precipitator and cooling chamber to collection container
  • 11. Air filter
  • 11a. Water Filter module
  • 12. UV lamps
  • 13. Water out let pipe
  • 14. Hot and Humid incoming air
  • 15. Warm Humid air after mixing with room air in the mixing unit
  • 16. Cold moisture saturated air from cooling unit
  • 17. Dry cold air after moisture precipitation
  • 18. Re-circulated air to be mixed with incoming air.
  • 19. Humid cold room air supply
  • 20. Semi-dry cold room inlet air
  • 21. Mixing chamber unit
  • 22. Collected Filtered and UV exposed potable water.

DESCRIPTION OF THE INVENTION

The most common refrigeration cycle uses an electric motor to drive a compressor. Since evaporation occurs when heat is absorbed, and condensation occurs when heat is released, air conditioners are designed to use a compressor to cause pressure changes between two compartments, and actively pump a refrigerant around. A refrigerant is pumped into the low pressure compartment, the expander unit (4), where, the low pressure causes the refrigerant to evaporate into a vapor, causing it to cool down below the temperature of the incomming air steam (14) taking heat from the air stream and hence cooling the air stream at the out put (16). In the other compartment, the compressor unit (1), the refrigerant vapour is compressed and forced through a heat exchange coil, condensing it into a liquid, rejecting the heat previously absorbed from the cooled air into the heat exchanger and hence to the outside. The heat exchanger in the condenser section is cooled most often by a fan blowing outside air through it, but in some cases can be cooled by other means such as water, especially on factory installations.

Refrigeration air conditioning equipment usually reduces the humidity of the air processed by the system. The relatively cold (below the dewpoint) evaporator coil condenses water vapor from the processed air, (much like an ice cold drink will condense water on the outside of a glass), sending the water to a drain and lowering the relative humidity, if the temperature is increased. Since humans perspire to provide natural cooling by the evaporation of perspiration from the skin, drier air (up to a point) improves the comfort provided. The optimum humidity is in the range of 40 to 60%. In typical air conditioning units the raltive humidity is not controlled actively. It is by default and hence it is never optimum as the incomming air after the precipitation of some of the moisture is still will be saturated. Hence the air coming out of the air conditioner is typically more humid than is comfortable, in most humid regions and seasons. The precipitated water is drained and discarded and not used in any of the current AC plants.

A typical implementation of the current invention is as follows( Other equipment configurations will be possible to achieve the aims of the invention that will be known and understood by the Air conditioning and Refroigeration experts. These though not specifically shown are covered under this disclosure): It is intented to optimize the precipitation of the water from the outside humid air (14) that is brought into the expander and cooling unit (4) after passing through an air filter (11) to remove particles form the stream. As it is cooled below the dew point, in the cooling unit, the water starts to condense on the fins of the cooling unit (4) but here is not enough time or surface area in the cooling unit to complete this process. This cold humid air(16) that come out of the coolling unit is passed through the intermediate vent (6) into a special precipitator chamber (8), where the rest of the moisture is allowed to precipitate prior to the air exiting the chamber through the out put vent( 7) of the precipitation unit (8) into the mixing unit (21) where the cold air that is now dry is mixed with re-circulating air(18) from the rooms to provide a room air supply(20) that will provide a suitable dry, cool atmosphere that is comfortable to living and working. By varying the proportion of the dry input air and the re-circulated air the necessary humidity and temperature can be maintained.

According to the current invention the condensed water in the cooling chamber (4) and the precipitation chamber (8) are collected and drained through drains(10) in the precipitation chamber into a precipitated water collection chamber (7).This collected water can be purified using various methods available to make it potable. Typically it can be filtered during this process using a filtration unit(1 la) placed in a suitable location in the path of collected water and the water can be exposed to UV radiation for destroying organisms collected using the suitably placed UV lamps (12). The collected water (22) is now suitable for use as drinking water and can be taken out through the out let pipe (13) and used. If the AC unit is situated on top of a high rise building, the water can be supplied to the appartments and users by gravity without further use of energy for pups etc. Hence saving power. The use of this water which today is partly an irritant by providing high humidity in buildings and partly thrown out as waste water from the condensor may be efficiently utilized to reduce the water needs in areas where high humidity is a given during certain seasons. By this means the stress on the water supply shemes can be reduced and time made available for preventive maintainance and the usage of water can be reduced. Since the water is easily purified it is suitable for drinking it will aliviate some of the problems faced by the tenants in most high rise buildings for drinking water.

The advantages of such a scheme are:

• • 1. Water that is going to waste is used efficently to provide potable water supply to the people.
  • 2. In most cases this water is available on the top of buildings and need very little effort in distribution.
  • 3. It will reduce the stress on water supply systems in urban areas where humidity is high.
  • 4. It can provide releaf to the watersupply systems and time for routine maintainance during humid seasons.
  • 5. It can reduce the high cost of drinking water in cities.
  • 6. The removal of excess humidity from the incomming air of the air conditioning units will make the living/working space more comfortable.
  • 7. The reduced humidity will reduce damage to furniture and fittings and reduce need for replacement.