Synthetic Bather Load

Urine is aprox. 95% water.
The other components of normal urine are the solutes that are dissolved in the water component of the urine. These solutes can be divided into two categories according to their chemical structure (e.g. size and electrical charge).

Organic molecules are electrically neutral and can be relatively large (compared with the ‘simpler’ ions – below).
These include:

  • Urea – Urea is an organic (i.e. carbon-based) compound whose chemical formula is: CON2H4 or (NH2)2CO. It is also known as carbamide. Urea is derived from ammonia and produced by the deamination of amino acids. The amount of urea in urine is related to quantity of dietary protein.
  • Creatinine – Creatinine is a normal (healthy) constituent of blood. It is produced mainly as a result of the breakdown of creatine phosphate in muscle tissue. It is usually produced by the body at a fairly constant rate (which depends on the muscle mass of the body).
  • Uric acid – Uric acid is an organic (i.e. carbon-based) compound whose chemical formula is: C5H4N4O3.
    Due to its insolubility, uric acid has a tendency to crystallize, and is a common part of kidney stones.
  • Other substances/molecules – Example of other substances that may be found in small amounts in normal urine include carbohydrates, enzymes, fatty acids, hormones, pigments, and mucins (a group of large, heavily glycosylated proteins found in the body).

Ions are atoms or groups of atoms that have either, lost some outer electrons, hence have a positive electric charge, or have gained some outer electrons (to the atom or group of atoms), and hence have a negative electric charge. Even in the cases of ions formed by groups of atoms (they are ions due to the few lost or gained electrons), the groups are formed from only a small number of particles and therefore tend to be relatively small.
These include:

Individual elements:
  • Sodium (Na+) : Amount in urine varies with diet and the amount of aldosterone (a steroid hormone) in the body.
  • Potassium (K+) : Amount in urine varies with diet and the amount of aldosterone (a steroid hormone) in the body.
  • Chloride (Cl) : Amount in urine varies with dietart intake (chloride is a part of common salt, NaCl).
  • Magnesium (Mg2+) : Amount in urine varies with diet and the amount of parathyroid hormone in the body. (Parathyroid hormone increases the reabsorption of magnesium by the body, which therefore decreases the quantity of magnesium in urine.)
  • Calcium (Ca2+) : Amount in urine varies with diet and the amount of parathyroid hormone in the body. (Parathyroid hormone increases the reabsorption of calcium by the body, which therefore decreases the quantity of calcium in urine.)
Small groups formed from a few different elements:
  • Ammonium (NH4+) : The amount of ammonia produced by the kidneys may vary according to the pH of the blood and tissues in the body.
  • Sulphates (SO42-) : Sulphates are derived from amino acids. The quantity of sulphates excreted in urine varies according to the quantity and type of protein in the person’s diet.
  • Phosphates (H2PO4, HPO42-, PO43-) : Amount in urine varies with the amount of parathyroid hormone in the body – parathyroid hormone increases the quantity of phosphates in urine.

http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V23-4K5SSYY-2&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&_docanchor=&view=c&_searchStrId=1025879066&_rerunOrigin=google&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=f1e240b72163bfa9d9b0ee60a58a8c0b

In conventional mixing ventilation air conditioning system, fresh air which has been polluted by recirculated air is supplied to occupied zone. Therefore, more fresh air which results in energy penalty needs to be supplied in order to keep good indoor air quality (IAQ) and thermal comfort. Some alternatives such as personalized ventilation air conditioning system can address this problem effectively by supplying fresh air directly into occupied zone. However, room layouts and visual effects will be influenced deeply because of extended air ducts. A new approach supplying fresh air directly by utilizing high velocity circular air jet without mixing with recirculated air is introduced. Objective measurements and computational fluid dynamics (CFD) tool are used to evaluate corresponding indoor parameters to verify that it can both supply fresh air into occupied zone effectively and avoid draught rating.

It is found that the measured air velocities are within the limits (0.25 m/s) of thermal comfort standards, although they are close to the limits. Higher air change rate can be obtained in breathing zone than that in ambient air in the background area. The predicted results show unique distributions of airflow characteristics and are in fair agreement with empirical measurements. Different angles of recirculated air diffuser blades, different lengths and directions of protruding fresh air jets and different inlet velocities of fresh air are adopted for comparing the effectiveness and efficiency of this new ventilation strategy numerically.

Keywords: Air jet; CFD; Draught rating; Air change rate

Article Outline

1. Introduction

2. Research methodology

2.1. Field measurements

2.2. CFD simulation

2.3. Parametric variation studies

3. Results and discussion

3.1. Field measurements

3.2. CFD simulation

3.3. Parametric variation studies

4. Recommendations

5. Conclusion

References

http://www.uppco.com/business/DisplayESource.aspx?BCType=2&type=PA&page=PA_54#ECA

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// HVAC: Dedicated Outdoor Air Systems

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In most buildings, HVAC systems combine fresh outdoor air with recirculated air in the main air handler for conditioning and distribution into the interior space. Some new buildings are using a different configuration called a dedicated outdoor air system (DOAS). In this design, the outdoor air is conditioned separately from the return air before it enters the building (see Figure 1). Dedicated outdoor air systems are a useful tool for improving humidity control and delivering precise amounts of ventilation air. Also, compared with conventional HVAC systems, they eliminate restrictions on the different types of HVAC components that designers can specify, and they often use energy more efficiently (see Table 1). However, the amount of operating cost savings varies widely in different applications and isn’t always necessary to make a DOAS application cost-effective, because its first cost may not be more than that of a conventional system.

Figure 1: Configuration of a DOAS versus a conventional system

A conventional variable-air-volume (VAV) HVAC system has a single, allpurpose unit for conditioning both return air and outdoor air (A). In a dedicated outdoor-air system (DOAS), the outdoor air and return air are conditioned in separate units (B). This configuration gives a DOAS the ability to improve humidity control, provide more accurate delivery of ventilation air quantities, allow designers to use a wider variety of HVAC components, and increase energy efficiency.

Table 1: Energy savings of a DOAS versus a conventional VAV system

When researchers compared a DOAS with a traditional VAV system, they found that less energy was necessary for space heating and cooling with a DOAS, but there were no overall savings in air-moving power. The researchers based their calculations on the following assumptions: the DOAS reduced the necessary outdoor air volume for ventilation by 20 percent, outdoor air constituted 50 percent of the heating load and 25 percent of the cooling load, and the COP of the compressor for the return-air unit was increased by 20 percent due to an 11°F increase in evaporator temperature.

Some of the buildings that are currently incorporating this strategy include all new U.S. federal government buildings designed in 2004 or later. In applying this strategy, a government engineer cited the dramatic improvement that a DOAS can make in controlling outdoor air, mold, humidity, and water penetration.

How Does It Work?

A DOAS doesn’t rely on new technology. It uses conventional HVAC equipment configured to condition outdoor ventilation air separately from return air. It is this technique that differentiates it from conventional systems. A DOAS requires two sets of equipment, one for outdoor air and one for return air, whereas a conventional variable-air-volume (VAV) or constant-air-volume (CAV) system requires just one.

Whether a building conditions air with a DOAS or a conventional system, there are two different types of cooling loads that the HVAC system must control:

  • Sensible cooling load. This is the energy required to cool air to the desired temperature.
  • Latent cooling load. This is the energy required to remove the moisture in air to reduce humidity to a target level.

By conditioning the outdoor air and return air in two separate HVAC systems, a DOAS effectively separates the two cooling loads. The outdoor-air HVAC unit removes the latent load to control humidity, and the return-air unit removes the sensible load to produce a comfortable temperature. It is possible to decouple the two loads because the primary source of building humidity in most climate areas is fresh outdoor ventilation air. The outdoor air unit can also handle the smaller amount of latent load from the building interior by providing air that is slightly drier than the target humidity level.

The outdoor-air unit typically cools and dehumidifies air in the summer and humidifies and heats or cools it in the winter. Therefore, the simplest unit consists of a preheating coil, a cooling coil, a reheating coil, and a humidifier. ASHRAE (American Society of Heating, Refrigerating, and Air-Conditioning Engineers) standards also require that a DOAS use energy recovery, which can be accomplished with a device called an energy-recovery wheel. Latent and sensible energy wheels transfer heat and moisture between building exhaust air and incoming air, thereby recovering energy that would have been lost to the outdoors and providing humidification or dehumidification (see Figure 2).

Figure 2: Typical DOAS outdoor air unit

In this dedicated outdoor air system (DOAS), the outdoor air first passes through a preheat coil, which is necessary for winter operation in many cool climates to avoid frosting of the energy wheel. Next, an energy wheel brings the outdoor air closer to the temperature and humidity of the conditioned exhaust air, and then the cooling coil cools and dehumidifies the air. A second energy wheel raises the temperature of the air to match that of the exhaust air, thereby preventing any overcooling before the conditioned outdoor air is fed into the building.

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What Are the Options?

There are three different configurations for DOASs. For delivery to the conditioned space, outdoor and supply airstreams can follow one of the paths described below (see Figure 3):

In a separately ducted system, outdoor air is conveyed to the zoned, conditioned space separately from supply air. After it exits the outdoor-air HVAC unit, the air enters the conditioned space through diffusers independent from any other mechanical system that may be thermally conditioning the space. Alternatively, the outdoor air may combine with return air in a mixing box or terminal unit that serves just one zone. In a zonal HVAC control system, individual zones of a building are controlled separately; the DOAS will deliver the proper amount of outdoor air directly to each zone. In a conventional system, the zone that requires the highest ratio of ventilation to total supply air dictates the fraction of fresh ventilation air that must be in the supply air leaving the air-handling unit. A DOAS can vary the fraction of ventilation to supply air, which can reduce the outdoor airflow rate by 40 percent. Energy savings result from conditioning only the amount of air necessary for each zone.

In a dual-path system, outdoor air joins the supply airstream in a mixing box before it enters multiple zones. When air leaves the outdoor-air HVAC unit, it may enter a mixing box or terminal unit that conditions air for more than one zone, or it can be added just downstream of the main return-air handler. The dual-path approach requires less ducting because it isn’t necessary to construct separate distribution systems for the two airstreams. However, this approach sacrifices the outdoor-air savings possible with a DOAS, because all zones receive the same ratio of outdoor air to return air.

Figure 3: Three DOAS configurations

The three common approaches to DOASs range from having completely separate systems (A) to configurations in which the two systems deliver conditioned air through one set of ducts (B) or the outdoor air unit is simply an extra conditioning step for the outdoor air before it’s conditioned together with return air (C).

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How to Make the Best Choice

When evaluating whether your building is a good candidate for DOAS, it is useful to know that savings are most likely to occur for facilities found in humid climates or those that need tight humidity control, such as libraries and museums or buildings that require a large volume of outdoor air. Because there is no comprehensive set of case study data, however, these guidelines are really the only ones that exist, so it is not simple to pick a good candidate for cost-effective application.

Cost-effective applications do exist, however, even though there is a general perception that a DOAS costs more than conventional systems because it entails replacing one all-purpose system with two parallel systems. Several case studies and a recent economic analysis show that in many cases the two can cost the same as, or less than, one all-purpose system. Supporting this point, the U.S. Department of Energy published a report in July 2002 on the energy savings potential of technologies for commercial-building HVAC systems. It listed the DOAS as one of the most promising technologies for energy savings, partly because of its low first cost.

The reason two parallel systems are not necessarily more expensive than one, with regard to new construction and major renovations, is that the DOAS can reduce the costs of other mechanical systems in a building. It may be possible to reduce the first costs of the following components:

  • Chiller or direct-expansion system
  • Condenser water pump
  • Ductwork
  • Air-distribution plenums and terminal boxes
  • Air handler
  • Electrical service for chillers, blowers, and pumps
  • Wasted “rentable” space that would have been consumed by mechanical equipment

For instance, by using a DOAS design instead of a conventional system, a medical clinic and office building in Missouri reduced the first cost of its HVAC system by 31 percent. This nine-story building was originally designed with a conventional HVAC system consisting of 16 air-handling units to bring in outdoor air for ventilation and to handle the space-conditioning needs. However, when the construction manager estimated the first cost of the conventional HVAC system, it came to $7,700,000 with the entire building exceeding the budget by about 10 percent. The designers went back to the drawing board and revised the design to incorporate a dedicated outdoor air system instead.

Using a DOAS reduced the cost of the HVAC system to $5,300,000—a reduction of 31 percent. This cost reduction was mainly due to simplifications of theHVAC system from the elimination of outdoor air ducting, louvers, and associated parts as well as simplified temperature controls for each of the 16 air-handling units.

This building reaped financial rewards from a DOAS, but the major benefit of conditioning outdoor air in a separate unit is being able to provide superior humidity control and precise delivery of ventilation air. In addition, compared to conventional HVAC systems, DOASs can use energy more efficiently and remove restrictions on the different types of HVAC components that designers can use.

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What’s on the Horizon?

We expect that in the future there will be more new buildings incorporating DOASs. It’s likely that this will allow researchers to continue to investigate this area by collecting first-cost and energy-consumption data from buildings that use DOASs. This experience will help designers and building owners become better informed about how to choose the most suitable systems for their buildings.

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The Science of UV Light
Ultraviolet Sterilization is unmatched in its efficiency, simplicity, and dependability when applied as a microorganism disinfectant. UV sterilization is a proven solution to waterborne planktonic algae as well as other harmful pathogen problems. Certain critical UV performance factors greatly affect all UV sterilizers, no matter who’s the manufacturer. The information contained in this outline should be considered before purchasing any UV equipment .
Factors Influencing UV Effectiveness

Whether you choose to label a UV as a clarifier or a sterilizer, the same design, performance, and operating principals apply. Successful UV operation destroys the targeted microorganism. Here are five main factors that will help determine the ability of a UV sterilizer (or clarifier) to achieve this desired effect.1. The type of lamp used in the application. (low-pressure or medium/high-pressure)
2. The length of the lamp being used. (the ARC Length)
3. The physical design of the UV’s water exposure chamber.
4. The condition of the water being treated.
5. The water flow rate through the UV’s exposure chamber
The Science of UVLet’s start at the beginning. Ultraviolet light is a spectrum of light just below the range visible to the human eye (below the blue spectrum of visible light in the chart above). UV light is divided into four distinct spectral areas-Vacuum UV (100 to 200 nanometers), UV-C (200 to 280 nanometers), UV-B (280 to 315 nanometers), and UV-A (315 to 400 nanometers). The UV-C spectrum (200 to 280 nanometers) is the most lethal range of wavelengths for microorganisms. This range, with 264 nanometers being the peak germicidal wavelength, is known as the Germicidal Spectrum.
The Targeted MicroorganismIt is critical to first identify the microorganism. Each type of microorganism requires a specific UV-C radiation exposure rate to successfully complete the disinfection process. The targeted microorganism must be directly exposed to the UV-C radiation long enough for the radiation to penetrate the microorganism’s cell wall. However, it takes only seconds for UV-C light rays to inactivate waterborne microorganisms by breaking through the microorganism’s cell wall and disrupting their DNA. This often totally destroys the organism, or at the very least will impair its ability to reproduce.
The UV Lamp… the Source of UVUV light sources primarily come as low-pressure or medium/high-pressure lamps. Low-pressure lamps produce virtually all of their UV output at a wavelength of 254 nanometers-very close to the peak germicidal effectiveness curve of 264 nanometers. These lamps generally convert up to 38% of their input watts into usable UV-C watts. This is much higher than other classes of lamps. (i.e. a 150-watt low-pressure lamp will have approximately 57-watts of UV-C power.) Low-pressure lamps typically run on low-input power currents of 200 to 1,500 milliamps and operate at temperatures between 100 and 200 degrees Fahrenheit. They have a useful life of 8,000 to 12,000 hours depending on the operating current of the lamp.
Medium/high-pressure lamps produce wavelengths widely ranging from 100 nanometers to greater than 700 nanometers, well into the visible light spectrum. These lamps are very poor producers of usable germicidal wavelengths; they generally convert only up to 8% of their input watts into usable UV-C watts. (i.e. a 400-watt medium-pressure lamp will have approximately 32-watts of UV-C power. The remaining 368-watts are converted into heat and visible light.) Medium/high-pressure lamps typically run on high-input power currents of 2,000 to 10,000 milliamps and operate at temperatures between 932 and 1,112 degrees Fahrenheit. They have a useful life of only 1,000 to 2,000 hours depending on the lamp’s operating current. As you can see from these comparisons, low-pressure lamps perform safely and efficiently. They are the better option for use in UV sterilization.

Low-pressure UV lamps come in many different styles and lengths. As a general rule, the longer the lamp, the greater amount of UV the water will receive because it will be exposed to the UV source for a longer period of time.
UV Lamp Length + UV-C Output + Useful Lamp Life = Lamp Value• UV lamp length is a critical performance factor that helps establish UV exposure.

• Evaluating UV lamp performance based on input watts is inaccurate! The “Input -vs- UV-C output Watts Chart above demonstrates the poor germicidal value of med-pressure lamps compared to low-pressure type UV lamps. Low-Pressure UV lamps convert approximately 38% of their input watts into UV-C output watts while the medium-pressure UV lamps convert 8%. Low-pressure style UV lamps offer greater germicidal value than medium pressure lamps for this reason.

• Knowing when to replace UV lamps is critical to achieving a consistent UV disinfection dose, but not all lamps offer the same useful operating life!

Design of the Water Exposure Chamber
The design of the water exposure chamber is completely overlooked by some manufacturers, but it is key to successful operation. The distance UV light energy has to travel from the surface of the lamp to the inner wall of the UV’s water containment vessel determines how much UV the water will receive. This is known as the “UV dose rate.” The amount of water passing through the UV filter ultimately determines the unit’s actual UV dose rate, which is expressed in microwatt’s per second per square centimeter or (u-watts-sec/cm2). When selecting a UV Sterilizer for your application:• Make sure the UV lamp is positioned between the water inlet and outlet ports of the unit’s water containment vessel. Any portion of the UV lamp(s) not located between the water ports is useless. When calculating the UV’s performance data, only the ARC length located between the water ports can be applied to the calculation, reducing its capabilities if portions of the lamp are not between the ports.

• Select the unit with the largest diameter water containment vessel in the wattage you are considering. A unit with a larger diameter will always have a greater contact time. (For example, a 25-watt model with a 3″ diameter housing will flow more water than a 2″ housing model.)

Single UV Lamp Array Diagram
Multiple UV Lamp Array Diagram
Open-Channel UV Lamp Array Diagram
• Make sure the unit you are considering uses a quartz sleeve. A quartz sleeve isolates the UV lamp from the water to avoid a short circuit path for the lamp’s electrical power. It also allows the lamp to operate at its optimum temperature by acting as an insulator.• Does the manufacturer list water flow rates at the end of a lamp’s life or the beginning? Most UV manufacturers give a water flow rate, but do not indicate whether it applies to a new lamp or to one that is at the end of its useful life. Try to find a manufacturer that includes the water flow rate in the unit’s end of lamp life rating. The end of lamp life rating takes into account the lamp losing UV-C output due to age so it is a more realistic prediction of how the unit will perform.

• Do the manufacturer’s water flow rates account for the reduced effectiveness UV light has when treating green water? This information should be listed as some type of percent transmissibility rate or absorption coefficient (decimal value). Units that account for green water will have lower water flow rates.

UV Transmittance
UV transmittance is also largely overlooked, but it is one of the most critical factors in determining the ability of a UV sterilizer to treat a given volume of water. Regardless of the type of UV light source used, any body of water containing impurities will adsorb UV energy. Green water, water plagued by algae and microorganisms, will absorb the UV energy emitted by our UV light source in proportion to its density (or how green the water is). The greater the amount of algae in the water, the more of a reduction in percent transmittance. Percent transmittance is the ability of a body of water to be effectively treated by a UV light source. This value indicates the quality of the water being treated. The higher the percent transmittance, the easier the UV sterilizer will be able to treat the water at a given flow rate. A lower percent transmittance means the UV sterilizer will be less effective in dealing with the algae problem. If the sterilizer’s water flow rates have not been calculated with a reduced percent transmittance rate, the unit will have considerable trouble dealing with an algae bloom.
Water flow rate through the UV’s contact chamber
A sound UV sterilizer design revolves around the careful selection of lamp type, lamp length, lamp position, and body diameter. These factors, together with the intended water flow rate, percent transmittance of the water to be treated, and UV dose rate needed to kill the targeted microorganism should be your basis for the selection of a unit for your pond. When researching which type of UV sterilizer to purchase, remember the criteria laid out in this article, read the manufacturer’s literature, ask questions, and most of all ask yourself, does this information make sense to me? If not, consider another UV manufacturer.Urine is aprox. 95% water.
The other components of normal urine are the solutes that are dissolved in the water component of the urine. These solutes can be divided into two categories according to their chemical structure (e.g. size and electrical charge).

Organic molecules are electrically neutral and can be relatively large (compared with the ‘simpler’ ions – below).
These include:

  • Urea – Urea is an organic (i.e. carbon-based) compound whose chemical formula is: CON2H4 or (NH2)2CO. It is also known as carbamide. Urea is derived from ammonia and produced by the deamination of amino acids. The amount of urea in urine is related to quantity of dietary protein.
  • Creatinine – Creatinine is a normal (healthy) constituent of blood. It is produced mainly as a result of the breakdown of creatine phosphate in muscle tissue. It is usually produced by the body at a fairly constant rate (which depends on the muscle mass of the body).
  • Uric acid – Uric acid is an organic (i.e. carbon-based) compound whose chemical formula is: C5H4N4O3.
    Due to its insolubility, uric acid has a tendency to crystallize, and is a common part of kidney stones.
  • Other substances/molecules – Example of other substances that may be found in small amounts in normal urine include carbohydrates, enzymes, fatty acids, hormones, pigments, and mucins (a group of large, heavily glycosylated proteins found in the body).

Ions are atoms or groups of atoms that have either, lost some outer electrons, hence have a positive electric charge, or have gained some outer electrons (to the atom or group of atoms), and hence have a negative electric charge. Even in the cases of ions formed by groups of atoms (they are ions due to the few lost or gained electrons), the groups are formed from only a small number of particles and therefore tend to be relatively small.
These include:

Individual elements:
  • Sodium (Na+) : Amount in urine varies with diet and the amount of aldosterone (a steroid hormone) in the body.
  • Potassium (K+) : Amount in urine varies with diet and the amount of aldosterone (a steroid hormone) in the body.
  • Chloride (Cl) : Amount in urine varies with dietart intake (chloride is a part of common salt, NaCl).
  • Magnesium (Mg2+) : Amount in urine varies with diet and the amount of parathyroid hormone in the body. (Parathyroid hormone increases the reabsorption of magnesium by the body, which therefore decreases the quantity of magnesium in urine.)
  • Calcium (Ca2+) : Amount in urine varies with diet and the amount of parathyroid hormone in the body. (Parathyroid hormone increases the reabsorption of calcium by the body, which therefore decreases the quantity of calcium in urine.)
Small groups formed from a few different elements:
Chemical Concentration (g/L)
Urea 100.58
Creatinine 15.6
Creatine Monohydrate 0.50
Lactic Acid 5.34 mL/L
Uric Acid 2.48
Glucoronic Acid 1.88
Sodium Chloride 35.5
Sodium Sulfite 56.72
Ammonium Chloride 11.16
Sodium Bicarbonate 10.76
Potassium Hydrogen Phosphate 18.24
Potassium Sulfate 16.22
Suntan Lotion 4.0 mL/L
L-Histidine 10 g/L
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