1. Corrosion Risks
Uninhibited glycol lacks corrosion inhibitors, which are essential for protecting metal components in the system. Closed loop systems often contain various metals, such as steel, copper, brass, and aluminium. In the absence of inhibitors, glycol can degrade and form acidic byproducts over time. These acids corrode the metal surfaces, leading to pitting, scaling, and eventual failure of critical components like heat exchangers, pumps, and pipes.

Corrosion not only weakens the structural integrity of the system but also causes the release of metal ions into the fluid. These ions can catalyze further degradation of the glycol, accelerating the corrosion process in a vicious cycle.

2. Decreased Thermal Efficiency
As corrosion products and scale build up on heat exchanger surfaces, the system's thermal efficiency declines. The accumulation acts as an insulating layer, reducing the effectiveness of heat transfer. This forces the system to work harder to maintain the desired temperature, leading to increased energy consumption and higher operational costs.

Additionally, glycol degradation products, such as organic acids and solid debris, can clog small passages within the system. Restricted flow reduces the system's ability to evenly distribute heat, creating hotspots or cold zones that further degrade performance.

3. Glycol Degradation
Uninhibited glycol is more susceptible to thermal and oxidative degradation, especially at elevated temperatures. Glycol degradation produces organic acids, such as formic and glycolic acids, which lower the pH of the fluid. Low pH conditions exacerbate corrosion, particularly in systems with aluminium or copper components.

Degradation can also lead to the formation of insoluble byproducts that settle in the system as sludge. This sludge impairs fluid circulation, clogs filters, and increases wear on pumps and other moving parts.

4. Microbial Growth
The absence of biocides or inhibitors in uninhibited glycol can promote microbial growth, especially in systems exposed to warm temperatures. Bacteria and fungi thrive in the nutrient-rich environment created by degrading glycol. Microbial growth can produce biofilms that adhere to surfaces, reducing heat transfer efficiency and accelerating corrosion. Biofilms can also harbour corrosive microorganisms, such as sulphate-reducing bacteria, which further damage metal surfaces.

5. Safety and Environmental Concerns
Degraded uninhibited glycol can become toxic due to the accumulation of acids, heavy metals, and other byproducts. Handling and disposal of contaminated glycol pose environmental and safety challenges. In contrast, inhibited glycol formulations often include stabilizers that prolong fluid life, reducing the frequency of replacement and minimizing environmental impact.

6. Increased Maintenance Costs

Systems using uninhibited glycol require frequent monitoring and maintenance to address issues such as corrosion, clogging, and fluid degradation. Regularly replacing the fluid and cleaning components can be labour-intensive and costly. Inhibited glycol reduces the need for such interventions by maintaining a stable and non-corrosive environment.

Using uninhibited glycol in closed loop cooling and heating systems poses significant risks to system performance, reliability, and safety. Corrosion, degradation, and microbial growth are among the most critical issues, leading to decreased efficiency, higher operating costs, and potential environmental harm. To mitigate these problems, it is essential to use inhibited glycol formulations designed to protect system components and ensure long-term, trouble-free operation. Proper fluid selection, along with regular maintenance and monitoring, is crucial for optimizing system performance and minimizing lifecycle costs.

Hydratech have been formulating and manufacturing heat transfer fluids, glycol formulations, antifreeze solutions, corrosion inhibitors, water treatment and conditioning chemicals to protect cooling and heating systems for over 25 years.

Utilising over 120 years combined experience in all aspects of refrigeration, HVAC and renewable energy applications, Hydratech's team of chemical, mechanical and sales engineers are ready to assist with all aspects of thermal performance, running costs, environmental impact, compatibility and energy efficiency.

Avoid costly glycol mistakes and improve your system’s efficiency and reliability, get in touch with Hydratech today:
e. info@hydratech.co.uk
t. 01792 586800