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CCAT outdoor solar shower

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Engr305 Appropriate Technology page in progress
This page is a project in progress by students in Engr305 Appropriate Technology. Please do not make edits unless you are a member of the team working on this page, but feel free to make comments on the discussion page. Check back for the finished version on May 23, 2019.


CCAT volunteers and co-directors have an issue of being dirty upon the premises after working on the grounds. Thus came the opportunity to find a solution for this problem through the use of a solar shower.

Opportunity Definition[edit]

The objective of this project is to successfully design, build, and create a solar shower using an appropriate technology-based solution.


What: Solar shower.

Where: Campus Center for Appropriate Technology at Humboldt State University.

Who: For the co-directors and volunteers at CCAT.

When: Spring semester 2019





Literature Review[edit]


Passive Solar Shower Basics

Our shower has three basic systems involved, solar collector, water storage and drainage. The solar collector must be made with materials that are efficient at collecting and retaining heat. The retention for heat depends upon the insulation of which the materials are located within. The solar uses a natural process called thermosyponing, which uses the pressure of warm water to push the cooler water, therefore circulating all the water to be warm with inside the system. Water storage must be placed above the solar catchment system, so that the warm water pushes to the top. The tank itself must be well insulated, so that during low periods of sun exposure, the water will remain warm. The drainage must properly disperse the water through using mediums made with different sizes of rock and correct slopes.

Passive Solar Shower Concerns

If temperatures becomes freezing, there is possibility of water freezing within the system. Another consequence of freezing water includes the non movement of water through the system, which would need a pump to circulate the hot water. In recent years Humboldt has experienced below freezing temperatures. The water tank that is installed must be above the system and is relatively heavy, so we must make sure our frame structure is safe enough to withstand high winds or earthquakes. In the sites proposed, there is a thought of lack of sun exposure or even proper insulation. There is also possibility of blockage due to mineral build up or other gunk expose in the system. Proper drainage needs to ensure no erosion nor flooding in nearby areas.

Types of Passive Solar Shower

Thermosyphon: A system where water is warmed through a solar collector and replaces cold water through the difference of pressure. This warm water is then completely circulated throughout the whole system, which would have to be an enclosed loop system. The tank is usually located above the solar collector to encourage thermosyphoning.

Batch: A system where water is directly heated by solar. The storage tank is heated with solar and then is immediately applied for use. The warm water is flowed first being then replaced by cold water, insulation is key in this system. [1]
  1. Design Interpretive Materials Solar: Corrugated metal/ rubber or metal tubing/ windows/ flat black paint Storage: 40-70 gallon tank/ valves/ shower head/ PVC pipe/ PVC fittings Drainage: rock slabs/ crushed rock/ PVC pipe Construction: 2X4/ screws

    Final Results[edit]


    [Grafman, L. (2017). To catch the rain. 1st ed. Humboldt State University Press.]

    Ling, Deli, Guanghu Liu, Genmao Mo, Junfeng Li, and Xiaojing Wang. "Research on Annual Thermal Performance of Solar Water Heating Balcony System." Energy Procedia 70 (2015), 71-78. doi:10.1016/j.egypro.2015.02.100.

    [Nix, S. (2019). Trees Use Thousands of Gallons of Water to Grow — Here's How. [online] ThoughtCo. Available at: [Accessed 21 Feb. 2019].]

    [Reif, D. (1983). Passive solar Water Heaters. Andover, Mass.: Brick House.]

    [Sitzmann, B. (2019). Solar Water Heater with Thermosyphon title [Accessed 21 Feb. 2019]. ]

    Gill, Nicholas J., Christopher R. Gibson, Gordon R. Waitt, Lesley M. Head, and Peter Osman. "Solar hot water giving you cold showers? Eight tips to warm you up", 2015.

    Mazria, Edward. “The passive solar energy book." Emmaus, Pa: Rodale Press, 1979.

    Bainbridge, D. "The Integral Passive Solar Water Heater Book" (1st ed.). The Passive Solar Institute, 1981. Available at: