Introduction
The goal of the operation and maintenance plan for this system is to ensure the system fulfills its role in CCAT. The plan is based off the concept of CCAT as a learning laboratory for appropriate technology, meaning that every project must be (a) appropriate, (b) educational, and (c) adaptive. In our conception of appropriate, we require the system to fulfil the appropriate technology (AT) field specific meaning and align with CCAT’s mission of helping users to ‘live lightly on the land.,’ But more, it must be appropriate for the specific circumstances of CCAT, in which it must be flexible so future students can adjust or use the system;, it must be educational for CCAT visitors:, and it must fulfill its purpose in CCAT. In terms of operations and maintenance (O&M), these mandates mean that the O&M plan must be straightforward, relatively low maintenance, accessible, and carried through multiple CCAT generations.
An overview of the plan is that the system is interacted with in summer, otherwise the operation of the system is passive - it can catch, pump, and store water by itself. The maintenance plan has weekly, monthly, and yearly components. The most important part of the maintenance plan is the annual cleaning, which should involve all Co-Directors as it is the main mechanism for the transfer of knowledge across CCAT generations. One of the most critical parts of the plan is information accessibility, so there will be user-friendly documents on site and online.
System Operations
System Operation :
The system is used by CCAT in the dry months, and in the wet months it can operate passively. It is easiest to understand the system as if it consists of two seperate parts: the wet side and the electric side. Essentially, the system catches, pumps, and stores rainwater to be used later, see Figure 1. Rain is caught on the roof, falls into the gutter, flows through the filter then over/into the first flush, and into the bottom storage tank system. The solar panel provides power to the pump, which pushes water up the hill to the upper tank when it is sunny. Opening the valve by the base of the solar panel allows water to flow out of the upper storage tank. The water from the upper tank gets delivered to the delivery hose which is near the pickle barrels in the bottom.
On the wet side of the system, water enters the system via the catchment area which is the tool shed roof. After getting collected in the roof the rainwater passes through the gutter which is also called the conveyance. The roof and conveyance are angled /tilted so that the water is conveyed with just the force of gravity. After passing through the conveyance the rainwater enters into the screen where the large debris, leaves and other particles are filtered out. Following that, the first few minutes of rainfall or the first few gallons of the rainfall enter the first flush. This is the dirtiest part of the rainfall which is not suitable for irrigation purposes. Once the first flush is full, water can pass over the top of the first flush and enter the three storage tanks which are next to the toolshed. The three storage tanks consist of one 250 gallon IBC tank and two 100 gallon pickle barrel tanks. The overflow pipe above the IBC tank helps drain water if the volume of rainfall is beyond the tank capacity. The water which is stored in the group of tans gets drawn by the solar water surface pump. The pump is powered by a solar panel located above it. The pump delivers the water to a 250 gallon tank which is situated up the hill. There are two points at which users can access the water. One of the outlets is attached to the hillside tank with a T connection. The other point is a located near the base of the solar panel, where a hose can be screwed onto the pipe. Both spigots are connected to the upper tank. To use this water, users can connect a hose to the spigot head near the base of the solar panel or on the hillside, then open the appropriate valve. Water should flow.
On the electrical side of the system, the solar panel powers the pump, but can be turned off by a water level sensor if there is not much water in the lower tanks. On a sunny day, the panel is in direct sunlight for less than 5 hours, usually from about 11 or 12 AM to 3 or 4 PM. During these hours, the 18 V panel can provide enough power for the 24 V pump to pump water up the hill (approximately 35 ft of head). The pump is a self-priming diaphragm pump, meaning that it increases its internal volume to pull water in from the inlet, then closes that valve and decreases its internal volume, pushing water out the exit (imagine a heart). The electrical side of the system is wired so that the pump can be disconnected from the panel via a water-level sensor located inside the IBC tank below the overflow pipe.
System Maintenance
The maintenance plan for the system is meant to be appropriately simple, help retain knowledge of the system, and allow for future students to use the system for class projects. In the interest of simplicity, the maintenance plan for this system consists mainly of cleaning the components, and checking the water quality annually (HSU water quality classes could do this, or CCAT could spend money to send a water sample to a local lab like North Coast Laboratories LTD).
The second goal of the maintenance plan is to help retain system knowledge. The first part of this is that the large-scale annual cleaning will help retain system understanding across multiple CCAT generations. In addition to this, it is hoped that the on-site O&M documents will help make the system accessible to all, and the more in-depth documents located online will be able to answer any questions.
Finally, the third goal of this maintenance plan is to assist in the education of others. The on-site documents should help educate volunteers or maintenance staff who are tasked with cleaning or using the system to water plants. The brochure, labels, and poster will also be accessible to those who are completing a self-guided tour of the CCAT grounds. The depth of the online documentation will hopefully allow future students to use the system for their own class projects (checking water quality or developing a solar shower, for example). The list of components will help provide future classes with information for their own projects as well as help CCAT with any replacements needed.
- 1. Maintenance Instructions
Below are instructions regarding the maintenance of the system. We recommend CCAT staffs and volunteer follow these steps in order to optimize the system’s function.
- A. Weekly
- Visual inspection: If there is a rain event, the water level should rise at least in the bottom tank. If there is sunshine on the panel, the water on the upper tank should also rise. If either of the tanks is already full, do not expect its water level to rise.
- Listen for the pump’s hum and feel the pressure of the pipe on a sunny day when the sun is shining on the panel (if the upper
tank is full, this won’t happen).
- B. Monthly
- Clean screen: Use hands, brush, or pressurized water.
- Clean gutter: Use hands, brush, or pressurized water.
- Measure solar voltage: Use the multimeter and connect to the solar panel’s wires. The voltage should be around Voc of the panel which is 22.3V.
- Wipe solar panels: Use biodegradable such as Dr. Bronner soap that is mixed with warm water.
- C. Yearly
- Clean the first-flush system: Take apart at the white connection point and hose it with pressurized water.
- Check water quality: Send water samples to a nearby lab if CCAT has the budget or if future building codes require. The nearest lab is the North Coast Laboratories LTD.
- 2. Cautions
- Avoid bending the HDPE pipe, the pipe may become permanently deformed.
- Avoid installing a solar module with a higher voltage than the water pump.
- Close the storage tank lids tight to avoid debris from entering into the storage system.