When it comes to pumping fluids, glycol can indeed be harder to pump than water. This is primarily due to the higher viscosity and density of propylene glycol/water mixtures compared to pure water solutions. Let’s delve into the specifics.
Viscosity refers to a fluid’s resistance to flow. The higher the viscosity, the thicker and more resistant the fluid is to flowing. Propylene glycol has a higher viscosity than water, meaning it is thicker and more “sticky” in nature. When mixed with water, the viscosity of the solution increases even further. This increased viscosity poses a challenge when it comes to pumping the glycol/water mixture.
In addition to viscosity, the density of a fluid also affects its pumpability. Density refers to the mass per unit volume of a substance. Propylene glycol has a higher density than water, and when mixed with water, the resulting solution has an even higher density. This means that the glycol/water mixture is heavier and denser, requiring more force to pump it through a system.
The combination of higher viscosity and density in propylene glycol/water mixtures leads to increased pressure drops in a pumping system. Pressure drop refers to the decrease in pressure as the fluid flows through pipes, valves, and other components of the system. The higher viscosity and density of glycol/water mixtures cause more resistance to flow, resulting in higher pressure drops.
To overcome these increased pressure drops, a pump needs to generate more pressure to maintain a desired flow rate. In practical terms, this means that pumping a glycol/water mixture will require higher pump pressures compared to pumping pure water. In fact, studies have shown that the required pump pressure can be around 25-35% higher for glycol/water mixtures compared to water alone.
The increased pressure requirements for pumping glycol/water mixtures can have various implications in different applications. For example, in heating systems that use glycol/water as a heat transfer fluid, the pump needs to be capable of generating higher pressures to circulate the mixture effectively. This can impact the selection and sizing of pumps for such systems.
In my personal experience, I have encountered situations where pumping glycol/water mixtures proved to be more challenging than pumping water. For instance, in an industrial cooling system, we had to use a larger and more powerful pump to handle the increased pressure drops caused by the glycol/water mixture. This resulted in higher installation and operating costs for the system.
To summarize, glycol can be harder to pump than water due to its higher viscosity and density. The increased viscosity and density of propylene glycol/water mixtures result in higher pressure drops in a pumping system, necessitating higher pump pressures to maintain desired flow rates. These factors can have practical implications in various applications, requiring careful consideration and selection of pumps to handle glycol/water mixtures effectively.