Evaporative tower technology is a cost-effective and environmentally friendly way to cool water used in many industrial processes. Climat applies this know-how to foundries, particularly aluminium die casting cells, improving the energy efficiency of the process
There are many industrial sectors requiring careful temperature control to optimize production processes or working environments. In most cases it is a matter of dissipating the heat developed by the operation of the machinery or the process itself, as in the confectionery or steel industry and in general in all hot production processes. But is it possible to achieve this objective without further burdening the energy balance of the production process, especially in the current scenario in which the fight against the planet’s climate change is ongoing? A very interesting answer, especially for the foundry sector, comes from Climat, a Brescia-based company which has been designing and manufacturing industrial and civil air treatment and conditioning systems and technological solutions for refrigeration or heating of fluids used in industrial processes for over 40 years.
As Fabio Calzolari, owner of Climat together with his brother Luca and responsible for design activities, explained, “an ecological and convenient opportunity to improve the energy efficiency of foundries and the quality of their products is offered by evaporative cooling technology applied to the water used to regulate the temperature of the plants and cool the castings. Actually, the control of the process temperature is an increasingly decisive variable to guarantee the quality and mechanical characteristics of the castings, especially for aluminium components for the automotive sector”.
The advantages of evaporative cooling
Evaporative cooling is a well-known principle and when large quantities of hot water need to be cooled, it is certainly the most economical and simplest solution from an installation standpoint. The economic saving consists in the fact that the process requires little energy, since it uses the latent heat of vaporization of the water. The heart of the system is the ‘Evaporative Tower’, where cooling is achieved by favouring the evaporation of a small amount of water, which in the transition from liquid to gaseous state removes heat from the remaining water. The reference parameter limiting the process is that relative to the wet bulb of the air; in Italy the maximum summer average value varies from 24°C to 25.5°C in the South.
With these values, the water can be cooled down to 29-30°C, a temperature suitable for use as a refrigerant in many industrial processes. Upstream, a careful assessment of the volumes and flow rate of chilled water required for the process is needed to adequately size both the storage tanks and the piping. But the realization is quite simple, even in the case of revamping of existing systems. “The foundry”, Calzolari underlined, “is an ideal field of application for evaporative technology. Our company is able to realize all the utilities needed to service the melting or die-casting cell, from the distribution of compressed air to methane to water for the cooling of shells and moulds. We approached this sector a few years ago, thanks to the collaboration with Ieci, specializing in the production of temperature controllers for the molding of plastics and metals, and we immediately verified that our know-how brings excellent performances with greater efficiency”.
Modular cooling for maximum energy efficiency
Climat’s entrance in the world of aluminium die-casting took place with a highly complex realization, precisely in partnership with Ieci: the project and the realization of the cooling system of a large die-casting machine which Idra built for a Brazilian customer. The cooling system was subdivided into separate and scalable modules to be transported and reassembled in Brazil, after a complete functional test carried out in Brescia. “The press is intended to operate in a continuous cycle,” Calzolari explained. “This required a largely redundant cooling system based on tower water and a 100 kW cooling unit to guarantee a water temperature of around 20°C. Besides, the machine is equipped with a next-generation variable flow cooling system with pressurized water, controlled by the press itself, which regulates the flow of refrigerated water to the different areas of the machine according to the actual cooling needs. This optimises the use of water and makes the energy balance even more convenient”.
Another confirmation of the validity of Climat systems comes from the plant recently supplied to the MAK foundry in Giussago (Brescia), specialized in the production of light alloy wheels for cars. Climat manufactured the technological systems (cooling, smoke suction and compressed air, hydraulic oil and methane distribution) to service two new robotized casting cells, consisting of two holding furnaces, eight shell machines and four wheel cooling tanks. An evaporation tower is used for cooling, which guarantees a flow rate of 40 cubic metres/hour of cooling water at 29°C, capable of cooling about 80 wheels/hour in a continuous cycle. This is an excellent performance, achieved with a low energy input and minimal water dispersion. An advantage for the company and for the planet.