# Innovating a DIY Solar-Powered Window AC: Design and Prototyping Insights
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Chapter 1: Introduction to Solar-Powered AC Systems
In this exploration, I am working on a solar-powered air conditioning unit designed to fit into a window, providing relief from the heat in my home. In my earlier write-up, I opted for common CPU cooling components due to their easy online availability. Now, I’m in the assembly phase, aiming to connect the basic elements, ensure safety, and verify that everything operates as anticipated while staying within my projected power limits. Initially, this setup will be powered by a standard 120v system reduced to 12v. Once I establish the actual power consumption, I will transition to a solar and battery-powered solution, allowing for versatility in energy sources.
Given the proximity of water and electricity, I’m incorporating fuses throughout the system. Since I’m utilizing 12v, there are excellent fuse blocks available from automotive suppliers that can be repurposed. I even discovered some useful fuseboxes designed for marine use!
Section 1.1: The Benefits of Using Fuse Blocks
Utilizing a fusebox for assembly streamlined the process significantly compared to using soldered power bus lines. Simply insert the appropriate fuses, and it’s ready to go. I believe I may have selected fuses that are too large for the Peltier units, as the total amperage for all four should only be around 5A rather than 17A. However, this setup is adequate for my current needs. This adjustment reduced what used to be an hour-long assembly into just five minutes.
Subsection 1.1.1: Simplifying Fan Connections
I acquired 40-pin right-angle connectors and soldered them onto boards to facilitate easier wiring for the fans. I later realized that two of my fans have lower power ratings compared to the others. If I choose to incorporate an Arduino for control, I’ll likely consolidate everything onto one board for simplicity.
Section 1.2: Choosing the Right Hose Clamps
It’s worth noting that there may be differences between hoses intended for cooling systems and those used in aquariums. For now, I’m using whatever is available. The most critical aspect is to select adjustable hose clamps. Initially, I tried using Sharkbite clamps, but they lack the ability to be disassembled for adjustments. I eventually found some effective spring band clamps that are easy to reposition and affordably priced.
Chapter 2: Assembly and Testing
In this first video, you’ll see the process of creating a DIY direct solar air conditioner. This prototype utilizes a R134a compressor, showcasing an innovative approach to cooling using solar power.
As I continued the assembly, I encountered challenges in organizing components. Eventually, I realized that the power supply could be mounted on the underside of the board, which optimized space.
Now, with everything in place, I just need to add water and connect the 110v supply—perhaps starting with the bench supply first.
I successfully connected the bench supply, and it’s running slightly over 12v at just above 15A, which aligns closely with my initial expectations of around 17A.
In this second video, I demonstrate how to operate a window air conditioner using just two solar panels during sunny conditions. This DIY project can be completed in a single day.
After running the unit for about thirty minutes, I noted a mere few degrees drop in temperature, prompting me to switch off the cold side fans to assess the temperature difference. An infrared thermometer indicated a remarkable 50°F (30°C) temperature differential, with frost forming on the cold side!
Section 2.1: Reflecting on Initial Results
Despite a few initial missteps—like confusing the hot and cold sides during testing—the system operates as I had envisioned. I am considering enhancing power management features, perhaps integrating an Arduino for better control and temperature logging.
I’m thrilled with how this prototype has turned out and look forward to refining it further. I have ideas for a vacuum-formed design that could simplify assembly and possibly allow for mass production.
Next Steps:
- Power the system using mains (110v) electricity.
- Acquire a 48v-to-12v @ 250W converter for battery operation.
- Test if my solar panel can generate the necessary 200W to run the unit.
- Reconfigure the setup so the hot side can extend outside the window while keeping the other components indoors.
- Operate in a room without air conditioning for several days to collect and analyze data.
- Implement drainage for condensation management.
- Elevate pumps on a block for easier filling.
- Add a low-side valve for emptying water.
I may consider collecting the condensation for use in watering my plants, depending on feasibility.
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