Blog Layout

Living with sink in structural injection molded parts: Sometimes you must break the rules

Project Overview:

Johnston Engineering recently completed a solar powered refrigeration system for our customer SolarXWorks. We provided complete system design, build and test. This system provides “cool” air conditioning or “cold” refrigerator conditions directly powered by sunlight. The system, solar panels and cooling tent is shown in Figure 1.

Figure 1 Solar powered refrigeration system keeping a tent cool

Advantage and usage:

Typical solar cooling systems lose up to 20% of the solar energy collected when they invert to AC voltage. Instead, this system uses 100% DC voltage and is very efficient. This product is highly flexible and can used for food transport and storage, commercial cooling applications, disaster recovery shelters or command and control shelters.

Figure 2 The system can be used for food transport and storage or remote facility cooling

Our contribution to the project:

Johnston Engineering provided the complete system design, build and testing. We provided program management, mechanical engineering including hardware design, refrigeration system design and structural analysis. We contracted the electrical engineering and software engineering, purchased all the hardware, built the system and tested and tuned the control software. The system is shown in Figure 3 and includes an evaporator and condensor, two fans, two compressors, a large battery, charge controller and many other components. The system is controlled using a Programmable Logic Controller and has a touch-screen panel interface. We designed the parts in 3D CAD software using SOLIDWORKS, and performed structural analysis in ANSYS. The exterior is covered in powder coated aluminum sheet metal which is fastened to a steel frame.