Let me start by saying that I am not a refrigeration engineer. I am trying to develop an application for my company and came across this forum. I am hoping that someone here can point me in the right direction. Here goes.

I need an insulated tank of FRESH water (approx. 48x48x48") in which I can vary the water temperature between 0 and 35 deg. C.

The warming operation is easy but I am having trouble sourcing a system that can do the cold part. I have to maintain water temperature when in cold mode between 0 and 1 deg. C. It will be 100% recirculated water - I just need a tank of cold water. In the past we have filled the tank with ice and let it melt - using the slush layer at the bottom as our 0-1 deg. C water. Not the most elegant solution.

The problem I am finding is that most chillers cannot go this low without freezing up unless you add salt or antifreeze. Unfortunately, I have to have fresh water.

Does anyone know of an off the shelf or semi-off the shelf solution for this system? Cost is a factor as I am trying to limit the total cost of the system to $3000 or less.

Any advice or help is appreciated. As an electrical engineer, I am out of my area of expertise and need some help!!

Thanks in advance!!