https://stacoolvest.com/ https://stacoolvest.com/ These are vests like you describe. You take ice packs from the freezer and fit them into pockets of the vest.

https://stacoolvest.com/ https://stacoolvest.com/ These are vests like you describe. You take ice packs from the freezer and fit them into pockets of the vest. Not very high tech but they work.