Design me a Product, Thermal -- 2

I am looking for an experienced Thermal Engineer who can do Thermal and insulation calculations, design of the container, and provide estimated costs of materials of a container 2/3 full of water with approx. dimensions 25cm x 25cm x 13cm (L x W x H). What I am essentially looking to do is decrease the internal temperature of water at 35C down to 5C. The internal dimensions are approx. 25cm x 25cm x 13cm (L x W x H). Once the internal temperature of water reaches 5C, I would like to hold that temperature as long as possible, hence why I am looking for calculations and an efficient insulation material but doesn't cost all that much. I've seen that Polyurethane is a good insulator, but not sure how expensive it is relative to other materials with similar properties. I would want a material which has great insulation properties, but cheap in price. I have tried using a substance such as Ammonium Nitrate and Urea which can provide thermal energy, however, it only decrease the temperature by a much smaller amount than what was desired. Please keep in mind, I cannot use ice packs for this project. I have also looked into the "electronics compressed-gas Duster and lint remover", when upside down it gives off a freezing temperature, but not entirely sure how, or if this would work. I think this project will involve the container being plugged in an outlet which can get the container to the desired temperature, a Peltier device, heat sink, batteries, cold air flow schematics design along with many other important characteristics for a great design. Maybe there is a way to add small solar panels on the outer surface to power, and charge the internal batteries. Sorry I do not have any 3D drawings, just pictures at the moment to provide more of a visual. Desired specifications: - Decrease the temperature down to 5C - Dial on the outer surface to allow for the user to set their temperature - Batteries to be rechargeable (can use small solar panels if needed, or charging from an outlet as an example) - Hold the desired temperature for 48 -72 hours without having to charge the batteries. - Weight to be less than 3Kg (the lighter the better). Thank you for all your time.