Dramatically improve factory air conditioning efficiency! Measures against hard water scale can reduce costs by tens of millions of yen per year

Why Hard Water Reduces the Efficiency of Your Air Conditioning System

When using air conditioning systems in factories, especially water-cooled air conditioners and cooling towers, the effects of hard water have a significant impact on air conditioning efficiency. Hard water is water that contains a lot of minerals such as calcium and magnesium. In general, factories that use groundwater or well water are more likely to encounter hard water.

When hard water passes through an air conditioning system, scale forms inside the pipes and on the surfaces of the heat exchanger. This scale is mainly composed of calcium carbonate (CaCO3) and magnesium carbonate (MgCO3) and has the characteristic of having an extremely low thermal conductivity. Specifically, the thermal conductivity of scale is about 0.6 W/m·K, which is several hundredths lower than that of common heat exchanger materials such as copper (about 400 W/m·K) and aluminum (about 230 W/m·K).

When this type of scale with low thermal conductivity accumulates on the heat exchange surface, the heat exchange efficiency drops sharply. For example, research has shown that a mere 1mm of scale accumulation can reduce heat exchange efficiency by up to 401 TP3T. As a result, the cooling capacity of the air conditioning system drops significantly, and more energy must be consumed to achieve the same cooling effect.

Harmful effects of scale on air conditioning systems

The impact of scale buildup goes beyond simply reducing efficiency: it causes multiple problems throughout the entire system.

First, the narrowing of the pipe inner diameter increases the resistance to water flow. This increases the load on the pump and leads to increased power consumption. From a fluid dynamics perspective, a 10% reduction in the pipe inner diameter requires approximately 1.5 times the power to maintain the same flow rate.

In addition, a decrease in the efficiency of the heat exchanger will extend the operating hours of the compressor, which will accelerate wear on the equipment and significantly shorten its lifespan. In general, it is said that for every 101 TP3T increase in operating hours of a compressor, its lifespan will be shortened by approximately 201 TP3T.

In the worst case scenario, thick accumulation of scale can lead to blockage of pipes and serious equipment failure. For example, if a cooling water pipe becomes completely blocked, an emergency shutdown of the system is required, which has a direct and serious impact on factory operations. The loss of a one-day shutdown can amount to hundreds of millions of yen for a medium-sized factory, depending on the industry.

Effective methods for preventing scale

There are various methods for dealing with scale, but it is important to select the most appropriate method depending on the factory's situation, water quality, and operating conditions. The main methods and their features are listed below.

1. Introduction of water treatment equipment:
– Ion exchange water softener: Replaces calcium and magnesium ions with sodium ions. High capacity, suitable for large-scale systems.
- Reverse osmosis equipment: A fine membrane is used to physically remove minerals. This produces water of high purity, but the initial investment and running costs are relatively high.
- Catalyst filter: Our proprietary "catalytic filter" technology, which utilizes our extensive experience in water treatment plants, can easily and inexpensively suppress scale generation and keep heat exchangers clean for long periods of time. In many cases, this catalytic filter is sufficient to prevent scale buildup.

2. Chemical Treatment:
- Adding anti-scalant: Chemicals such as polyphosphates and phosphonates are used to suppress mineral precipitation. This can be introduced at a relatively low cost, but regular replenishment of the chemicals and water quality management are required.

3. Physical Treatment:
- Electrical water treatment equipment: Electric or magnetic fields are used to change the crystal structure of minerals and prevent scale buildup. This is environmentally friendly as it does not use chemicals, but there is an issue with the sustainability of the effect.
– Sonication: High frequency sound waves are used to inhibit mineral crystallization. This is a relatively new technology whose effectiveness is currently being tested.

4. Regular cleaning:
– Mechanical cleaning: physically removing scale using brushes and scrapers. This is a reliable method but requires effort and system downtime.
– Chemical cleaning: Dissolves scale using an acidic solution. This is effective, but care must be taken when dealing with the effects on pipe materials and waste liquid disposal.

Combining multiple methods will provide more effective anti-scale measures than using one method alone. For example, using a water softener in conjunction with chemical treatment will minimize scale formation and extend the life of the equipment.

Maintaining the efficiency of air conditioning systems by preventing scale

By taking appropriate measures against scale, it is possible to maintain the efficiency of an air conditioning system over the long term. The effect of maintaining efficiency can be quantified as follows:

1. Reduce energy consumption:
By preventing the deterioration of heat exchange efficiency caused by scale, it is expected that energy consumption can be reduced by approximately 5-15%. In the case of large-scale factories, this will lead to cost reductions of several million to several tens of million yen per year.

2. Extend equipment life:
By reducing the load on equipment caused by scale adhesion, the lifespan of major equipment can be extended by approximately 20-30%. This reduces the frequency of equipment renewal, and reduces long-term capital investment costs.

3. Optimizing maintenance costs:
Regular anti-scaling measures are costly, but they can significantly reduce the risk of sudden breakdowns and emergency shutdowns. In some cases, planned maintenance can reduce annual maintenance costs by approximately 10-20%.

4. Stabilizing system performance:
Preventing the accumulation of scale helps maintain stable performance of the air conditioning system, which contributes to a more stable production environment and improved product quality.

Balancing environmental friendliness with anti-scale measures

Scale control measures not only have economic benefits, but also contribute greatly to reducing the environmental impact. Specifically, the following effects can be expected:

1. Reduction of CO2 emissions:
Keeping your air conditioning system efficient reduces energy consumption, which for large factories can translate into hundreds of tonnes of CO2 reduction per year.

2. Effective use of water resources:
The introduction of water treatment equipment can improve the quality of water used in factories and increase the reuse rate, which can reduce water resource consumption by 10-201 TP3T in some cases.

3. Optimizing chemical usage:
Proper scaling control reduces the amount of chemicals used for cleaning and flushing, which helps to minimise chemical emissions into the environment.

4. Improving overall environmental performance:
Implementing a comprehensive environmental management system that includes anti-scaling measures can facilitate achieving and maintaining environmental management system certification such as ISO 14001, which is a key indicator of a company's environmental stance.

Furthermore, scaling countermeasures that utilize the latest environmental technologies are also attracting attention. For example:

– Water treatment system combined with solar power generation:
By linking water treatment equipment that consumes a lot of electricity, such as reverse osmosis membrane equipment, with a solar power generation system, advanced water treatment can be achieved while minimizing the environmental impact.

– Geothermal air conditioning system:
Taking advantage of stable underground temperatures reduces the need for cooling towers, reduces the risk of scale formation and improves energy efficiency.

– Optimal control system using AI:
Systems are also being developed that use machine learning algorithms to analyze water quality data and operational data and automatically determine optimal scale prevention measures and operating conditions.

In this way, anti-scaling measures are not just a simple solution to the problem, but are an important factor in achieving both efficient factory operation and environmental friendliness. Taking appropriate measures will lead to improved factory management and the realization of sustainable production activities from a long-term perspective.