Enhancing Cooling Capacity on a Dairy Farm

The Challenge

The largest dairy producers in the world demand massive milk storage tanks. In this case, multiple 60,000-gallon (227,124.6 liter) Paul Mueller Company milk silos were required. As part of the cooling solution, plate heat exchangers were implemented to help precool/instant cool milk before it went into each silo. When this producer bought heat exchangers from a competitor, they found the units could not keep up with milk cooling demands. Proper cooling enhances milk quality, and they need lower temperatures to maintain cool milk temperatures during long-distance shipping. With such tremendous milk flow rates, this dairy producer needed help—and they needed it fast.

The Journey

Mueller experts were called upon to help determine why the competitor’s plate heat exchangers were failing. Paul Mueller Company drew from a wealth of knowledge of dairy farm equipment accumulated over more than six decades to assess the situation. They knew that oversizing the plate heat exchanger would make it inefficient, while undersizing the equipment would render it unable to keep up with demand.

Data was collected to calculate the correct plate heat exchanger specifications. Several questions need to be answered for precise temperature control:

• What was the operation’s milk flow rate?
• What was the temperature of the milk?
• Was well-water precooling being employed?
• If so, what were the well-water temperature and flow rates?
• What was the chilled-water flow rate?

The answers to these questions revealed that the plate heat exchangers needed less milk pressure drop. Massive plate heat exchangers, not typically used on dairy farms, would be required. A consultation with Paul Mueller Company engineers confirmed the findings, as well as the flow rate and port size requirements.

The Solution

It was settled. AT-40 Accu-Therm® plate coolers, also known as plate heat exchangers, could handle the extraordinary cooling needs of this dairy operation. Each high-efficiency, multi-pass AT-40 Accu-Therm® plate cooler would utilize 149 plates, well-water precooling, and a propylene-glycol water chilling loop for success.

Accu-Therm® plate coolers have a series of sanitary (type 316) stainless steel plates compressed in a frame. Separated by gaskets to contain pressure and control flow, these plates form channels. Fluids run through these channels. When using plate coolers on a dairy farm, cool water flows up the channel on one side while warm milk flows in the opposite direction on the other side. The milk's temperature drops as its heat transfers to the cool water. The corrugated plate design enhances heat transfer capabilities for ultra-efficient, fast precooling.

The Results

Mueller considered all the operating equipment and variables on this farm to form a complete, custom cooling solution. Expert equipment sizing was vital. The AT-40 Accu-Therm® plate coolers keep up with cooling demands and protect profitability. The dairy producer can supply their product to an expanded market without investing in additional facilities—all with the utmost confidence in their milk quality.