Replacements and Refurbishments
CTMS is the most experienced cooling tower company in the pacific region. You can be assured that your project is in safe hands when using CTMS. CTMS has been operating since 1985 and has carried out over 50 million dollars in cooling tower work in that period.
We specialize in change over and maintenance work that requires minimal impact on the building or service and must be completed in a predetermined time line. CTMS carries out project across Australia, New Zealand and the Pacific Islands. Scope from Laundries to Power Plants.
The hardest decision is whether to replace or refurbish.
Water-cooled chillers may be replaced with air-cooled models.
Benefits to air-cooled chillers include:
- Do not use cooling towers, eliminating the condenser water loop
- Do not consume water
- Do not regularly discharge chemicals and water to the sewerage system, as there is no need for a bleed system.
- Carry no risk of Legionnaires disease.
- Require little water treatment other than ensuring the chilled water corrosion control chemicals are periodically checked
- Are easier and cheaper to maintain than water-cooled chillers as they do not require an annual clean of the condenser water box. Small (rated less than 500kW) chillers may have lower operating costs.
Disadvantages of air-cooled systems include:
- Comparatively more expensive to purchase
- Occupy greater floor space
- Can have a significantly greater electrical demand
- Are noisier, bigger and heavier
- Have lower heat transfer efficiency: on very hot days their performance may be compromised and they may have heavy electricity demands.
Geothermal systems make use of the fairly constant temperature of the ground. Instead of using a cooling tower, cooling water is passed through a series of long loops buried deep in the ground. The unwanted heat is passed to the soil and rocks, where it dissipates. Since this is a closed loop system, there is little or no water usage. Initially it is more expensive than conventional cooling systems, however because the ground temperature is fairly constant and relatively low, it is possible to achieve very high efficiencies. They are low noise, have almost no Legionella risk and are relatively low maintenance. However, they require drilling bores, which is impractical in built-up areas. Water source geothermal systems directly or indirectly use underground aquifers. Direct use systems draw water from the ground, pass it through a heat exchanger and return it to its source. Indirect systems use closed pipe work loops that pass through the aquifer. Indirect systems are often comparable in cost to a conventional water-cooled system.
Ice and chilled water storage systems
Using ice storage and chilled water storage systems overnight can save water and considerably cut operating costs by using electricity at off-peak rates. Capital costs can also be reduced because it is not necessary to install large chillers, etc. to deal specifically with peak loads on only perhaps 10 days of the year.. These systems potentially save 15 per cent in electrical energy. Ice systems take up less space than chilled water systems. Their installation is dependent upon skilled engineering design and manufacture. For this reason they are generally used in large installations. Seek advice from qualified professionals at the design stage.
Sea or River Water cooling
When a building is close to a large water source such as the sea, river or lake, there may be an opportunity to take advantage of the natural heat sink. Several buildings in Sydney, including the Sydney Opera House, make use of the harbour for cooling purposes. Some of the newer buildings in Melbourne's Docklands use sea cooling. Issues to consider include the choice of metals where heat exchanges come into contact with highly corrosive seawater, macro-organisms such as mussels that can foul heat transfer equipment, and limits of chemicals such as chlorine that can be discharged to the water body. Initial costs are normally higher than a conventional water-cooled system; however this may be outweighed by overall benefits.
Liquid coolers are a similar concept to car radiators, with the cooling tower replaced by a heat exchanger and fan. This is the most basic form of liquid cooler, called a dry cooler. The cooling water is pumped through the heat exchanger and a fan forces air over it. The air picks up the heat and removes it. Because this is a closed loop system, there is little or no water use. The main disadvantage is that dry coolers suffer reduced efficiency at higher ambient temperatures. This can be overcome in several ways. The simplest is precooling the air by water sprays before it enters the dry cooler. Sprays are activated when ambient temperatures become high. A disadvantage of spray coolers is that they must be installed and operated with care to prevent the formation of scale on the surface of the dry cooler. Alternatively, pre-cooling pads have the advantage of not creating water droplets on the dry cooler surface. Provided the cooling pad systems are properly installed and operated, they present a very low Legionella risk by virtue of their operating temperature.
Another alternative is a hybrid cooler, similar in principle to the wet/dry cooling towers, except that the condenser water circuit remains closed. A section of the cooling coil surface is wet with water recirculated from a sump at times of high ambient temperature, but at other times the cooler acts as a normal dry cooler. By draining the sump at night (when the load on the cooling system is generally low, especially for air-conditioning applications) and running the cooler dry for a few hours, hybrid coolers can be Legionella-free and do not need microbial water treatment. The significant advantage over a conventional cooling tower is lower annual average water consumption.
Wet/dry cooling towers
Such towers use the positive aspects of both systems leading to overall reduce water consumption. Water to be cooled is passed through the dry air-cooled section then through the wet section of the cooling tower. During the cooler periods only the dry cooling tower section is used, reducing water consumption.