Appendices Phoenix Public Facilities Application Guide, 2003

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Above, the 50-gallon tank, which measures 26 by 41 by 15 inches high. The 100-gallon tank measures 26 by 41 by 28 inches high. The 12 or 24-volt d.c. fan draws 20 watts. The 110-volt a.c. blower draws 350 watts.

The evaporator is designed for evaporative efficiency, durability, reliability, and easy maintenance. The insights of maintenance personnel in the field were invaluable to us in developing this product.

Phoenix Auxillary Evaporator

Principles. Leachate from the Phoenix is generally free of coliform bacteria, but can have significant amounts of nutrients such as phosphates and nitrates. At some sites it is imperative to keep these nutrients out of the environment to avoid eutrofication of surface water. Because the leachate is mostly water, evaporation is often a practical and affordable alternative to transporting it from the site.

Evaporators require a steady flow of warm, dry air to provide the energy to vaporize the water. Evaporation is more efficient, requiring less air flow, under hot, dry conditions than under cool, wet conditions. In cool and/or moist climates, preheating the air that is blown through the system increases the evaporation rate, but the process is energy intensive.

As a general rule, using solar collectors to support preheating the air is more economical and environmentally sound than using electricity or burning hydrocarbons. For sites that are off-grid and off-road, solar collectors are the only practical source of preheated air.

Planning. Evaporation potential is maximized by integrating the evaporation hardware with the building, and by performing a site-specific analysis of the parameters affecting evaporation prior to designing and constructing the facility. We can analyze the evaporation potential for your site so that your installation's configuration is optimized for your conditions.

ACS Evaporators. Our evaporator's design is based upon the pioneering work of the New York Department of Environmental Conservation. The system consists of a tank that stores surge flows, and an evaporation tower containing an evaporative medium with a large surface area to volume ratio. A pump sprays liquid on the media in the tower while a fan moves air through the tower, accelerating evaporation. The control system monitors the level of the liquid, and optionally, humidity and temperature.

Capacity. In relatively warm (95° F, or 35° C) and dry (25 percent relative humidity) conditions this system can evaporate the leachate from 30 toilet uses per day, approximately 1-1/2 gallons. The higher volume a.c. blower increases the capacity. A larger system with more media and higher air flows can evaporate the leachate from 100 uses/day. Higher humidities and/or lower temperatures reduce evaporation rates significantly.

Encomium From a Satisfied Customer

Each summer, 75,000 tourists hike 1.1 miles down to the shore of Crater Lake to take a boat ride or enjoy the water. Human waste is a continual maintenance problem.

A composting toilet helped but 600 gallons of liquid still had to be packed up the trail each year. Last year, a liquid evaporation system solved the problem.

Solar panels provide electricity to pump fluids from the holding tank into the top of a drip-tank filled with plastic balls which provide tremendous surface area for evaporation. A small fan aids evaporation. At season's end, all the liquids completely evaporated. The system functions perfectly and the crews no longer haul liquids up the trail.

Published in the January, 1996, issue of the National Park Services's Pacific Northwest's Field Area's Maintenance News.

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Phoenix Electrical Loads & Photovoltaics
Phoenix Electrical Loads & ACS Solar Systems (PDF)

Cedar Ridge PhotovoltaicsOff grid qualified. The Phoenix has extremely low electrical requirements, and thus is ideal for off-the-utility-grid installations. This is by design.

Typical loads. The Phoenix's 12-volt d.c., 5-watt ventilation fan nominally consumes 120 watt hours each day. A 24-volt fan is optional. During periods of low use, such as midnight to dawn, the fan can be slowedto a 2-watt draw, reducing daily energy consumption by 10-20 percent.

Photovoltaics. In reasonably sunny climes, a single 64-watt photovoltaic array and matched lead-acid battery and charge controller can power both the Phoenix and small loads such as lamps. An additional panel, and/or auxillery generator, may be necessary in cloudier situations, and/or more northerly latitudes. Typical configuration (GIF).

Wind and micro-hydro. Even the smallest systems usually can handle the Phoenix with ease, and without requiring significant adjustments in electricity consuming activities.

Hydrocarbon fueled generators. Although less friendly from an environmental standpoint, these are viable options both as backups for renewable energy systems and as primary systems. Even a 500-watt generator can recharge a battery in an hour or two.

How we can help. We design, manufacture, and install photovoltaic systems that are reliable, efficient, and affordable. We can supply individual components such as photovoltaic panels, battery charge controllers, batteries, mounting hardware, inverters, and hard-to-find d.c. lights and pumps.

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Which is best - low voltage d.c. or inverter supplied 120 - volt a.c.?

There is no simple answer. We recommend starting with d.c., adding an inverter only if 120-volt a.c. is unavoidable.

Low voltage direct current. Twelve and 24-volt d.c. systems have fewer components, thus greater efficiency and reliability and, usually, lower cost. All of the Phoenix's electrical components are powered by c.c., and we use d.c. for the lights and pumps in all off-grid toilet buildings.

Inverter supplied alternating current. Standard 120-volt a.c. requires smaller wires than 12 or 24-volt d.c. for a given load, important for long runs of wire. Some electronic and motorized equipment requires a.c. Some maintenance electricians are more comfortable with a.c. An inverter increases system complexity while reducing reliability and (usually) efficiency, and adds to the cost.

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Appendix C - A Case Study in Energy Efficiency

ACS designed and installed a photovoltaic system that reduced pollution and brought peace and quiet to the north entrance station for Crater Lake National Park in Oregon. This project was successful not only because the site was suited for solar energy, but because a careful analysis of the entrance station's true electrical needs was performed prior to initiating design. The story below appeared in the January, 1996, Maintenance News, published by the Pacific-West field area of the National Park Service.

Photovoltaics Power An

Energy Hungry Entrance Station

New technology soothes rattled nerves, improves working conditions and silences gasoline generator at beautiful Crater Lake NP. All this without polluting the air or burning a single hydrocarbon.

The North Entrance Fee Collection Station at Crater Lake National Park is only open about 100 days every summer. This does not, however, diminish the station's energy needs. Commercial power is [not] available to this remote location. An 8000-watt generator filled the bill, powering electric heaters, large light fixtures and fans.

Life with a generator.

The thirsty generator was fueled 2 or 3 times a day by station employees shuttling gasoline in the trunk of their cars. The generator's oil was changed every week.

The station's remoteness had one advantage: it allowed thieves time to dismantle and steal the generator.

The staff and management had mixed emotions about their loss. The theft, in truth, did have a silver lining: managers decided to operate the station with a photovoltaic system.

Starting over.

To design the new system, four major issues were addressed. The park needed to

  • Reduce electric loads as much as possible.
  • Minimize operational and maintenance costs.
  • Meet architectural concerns.
  • Prevent potential vandalism.

Creative Solutions.

Catalytic propane heaters (12V ignition) replace electric heaters, 3M window tinting reduces heat buildup on hot days, high efficiency light fixtures went up, and 12-volt circuits minimize loss associated with voltage inverters.

Batteries are easier to service because they are mounted on a simple cart and two [charge] controllers provide MSX-64 photovoltaic redundancy (essential to any well heeled PV system).

Placing the panels on a 45-foot pole 300 feet from the entrance station solved architectural and vandalism concerns. The batteries and controllers are cleverly hidden in the old generator house, some 150 feet from the entrance station. To the untrained eye, it appears the fee station now has commercial power.

The project costs ($9,500.00) were shared by Crater Lake national Park, the Columbia/Cascades SSO, and Sandia Labs.

Big savings.

The photovoltaic system has been in place for 1.5 years. It is very reliable and operational costs are minimal. In fact, savings realized by the photovoltaic systems will pay for the improvements in just 9.5 years. Factoring inflationary increases, the payback period decreases dramatically. The biggest savings are for the environment because Crater Lake will NOT use some 5.000 gallons of gasoline and 300 gallons of oil during the payback period.

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Appendix D -- ACS Modular Prefabricated Buildings

Advanced Composting Systems manufactures and installs a wide variety of facilities compatible with the Phoenix Composting Toilet. The design of each building addresses the specific conditions and needs at a particular site, such as climate, location, the type and amount of use, and accessibility for the handicapped. We then prefabricate the building in our climate controlled factory.

Example (drawing, opens in new window).

We specialize in the design and prefabrication of structures that must be transported to remote sites by helicopter, boat, raft, or all-terrain vehicles (ATVs).

Advantages of prefabrication. Prefabrication provides superior quality control and, by eliminating delays caused by inclement weather, shortens the time needed for construction. Because only building components are transported to the site we need fewer trips.

On site, the project moves forward rapidly and quietly. Most often we are able to erect an entire facility in less than a week using only electricity from the sun. Hydrocarbon fueled generators are not necessary.

Integrated design. All of the services and features below are tightly integrated into a compact, efficient design that not only is pleasant for users but convenient for maintenance personnel.

Environmentally friendly materials. Our buildings are constructed using environmentally friendly, durable materials.

  • Ammonical copper quatenary (ACQ) pressure treated wood is used for the permanent wood foundation. Unlike chromated copper arsenate (CCA), ACQ contains neither arsenic nor chromium.
  • Planks extruded from recycled plastic and wood waste (Trex is a popular brand) are used to construct the deck, ramp, railings and balusters.
  • Cellulose-cement siding provides fire and decay resistance and unmatched longevity.
  • Board made from soybean or sunflower seed waste is used for a small but convenient shelf in the toilet room.

On-site resource generation. As the drawing on page 17 shows, ACS facilities can provide many services in addition to the Phoenix -- even when hookups to conventional utilities are unavailable.

  • Photovoltaic panels provide electricity.
  • Rainwater collected from the roof is stored in basement cisterns; a pump provides pressurized water for maintenance and hand washing.
  • A solar heat collector built into the roof framing delivers hot air that warms the basement.
  • An earth tube delivers cool air that cools the toilet rooms in hot climates.

Staying within the resource budget. The efficient use of resources that are collected on-site requires faithful adherence to a resource budget. Our strategy for staying within a structure's resource budget includes:

  • Well insulated building walls to retain or reject heat.
  • Efficient compact fluorescent lamp or low power, long life, light emitting diodes (LEDs) to provide nighttime illumination.
  • Automatic faucets provide water for hand washing with minimum waste.
  • Programmable logic controllers monitor temperatures, the amount of use, and other conditions, so that electricity is used efficiently.

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