Make-up Air for coating processes and preparation stations

High-energy efficiency and low environmental impact leads to maximum production output

 

Compensazione e reintegro aria edifici indutriali

Modern buildings for eco-efficient processes in complete safety

In order to improve certified energy performance of industrial buildings, it is essential to control the fresh air supply in the paint shop and in the paint preparation areas, providing a clean and safe environment that is eco-efficient with low energy consumption.

The renewal of air in industrial processes creates a healthy and safe environment for operators. Combined with an intelligent management of resources used for summer and winter air conditioning it leads to a clear cost reduction of expensive paint shop operations.

The choice of heating and ventilation systems of a paint shop and preparation areas has to take into account the total installed cost.  A shortsighted choice will lead to very high unexpected costs, unhealthy and unsafe workspace and poor productivity.

What is Make-Up Air?

Within a body shop or any spray painting and substrate preparation environment, where fillers, solvents and other materials for repairing plastics and fibrous components are applied, a considerable amount of dust, odors and other suspended particles of chemicals are generated. If these substances accumulate in large quantities, they can be harmful to the health of operators.

The most effective solution is to replace the air inside the room with fresh outside air, restoring the indoor air quality. This Make-Up Air operation is typically can be determined by specific regulations, as hazardous substances are emitted, or linked to rules related to hygiene and the well-being of operators.

First, it is necessary to understand which substances are being processed. Therefore, a risk analysis related to the work carried out on site has to be conducted. Furthermore, the type and location of the building, the number of operators and their working habits must be analyzed.

Air renewal affects the energy balance of the building

During the process of replacing indoor air with fresh outdoor air, a first fundamental aspect must be taken into account: the temperature difference between the intake and exhaust air. If this air exchange is carried out in spring or summer or, even worse, in winter, hot or cold air will be introduced and will have to be heated or cooled, with a considerable use of energy.

The second aspect to take into consideration is the internal pressure of the building. Normally this value is equal to atmospheric pressure (which we consider to be zero) as the air is stationary and will fill the room evenly. As soon as the air is moved by means of extractors or ventilation units, the air will start to create a pressure difference inside the building, which can be positive or negative depending on the balance. The effects of a non-zero pressure can be easily noticed on the building’s doors: difficulty in opening, noisy closing and even uncontrolled opening and closing. Depending on whether the pressure is positive or negative, it will either push out conditioned air or attract unconditioned air, affecting the building’s energy balance.

In the past: acceptance of low energy efficiency of industrial buildings

All body shops need preparation areas where the substrate to which the paint will be applied can be safely worked on. These areas were normally equipped with dust and odour extractors. These machines create a negative pressure inside the building so that fresh air is passively sucked in from outside through windows, doors, gates and simple draughts naturally present in buildings.

Impianto con pressione negativa

Modern buildings are required to be energy efficient, reducing running costs and providing environmental comfort for operators. This type of building cannot afford to waste energy on a dust extractor.

A simple solution may be the partioning of the work areas of buildings by isolating some areas and leaving others with free air renewal. This requires high masonry costs and only partially solves the problem.

Today: three specific solutions for every need

The first step to accurate fresh air management is to calculate the amount of air required for the process. Especially whether this is constant during the working day or varies according to the processing phases. An example: there are three 19,000 m3/h extractors; one runs all day (fresh air = 10% > 1,900 m3/h) while the other two run alternately with a peak of three extractors at the same time. The amount of fresh air thus varies from 1,900 m3/h to 5,700 m3/h (1,900 m3/h x 3).

The second step is to calculate the heat output required to heat or cool this volume of air. In the case of heating, the capacity varies (considering a DT of 20°C) from 13 kW to 40 kW. Similarly, it is possible to calculate the capacity required for summer cooling.

Having this data, we can act in different ways:

  • Increase the air conditioning potential and capacity of the building’s existing heating/cooling system
  • Compensate the extracted air with a heat generator (in the case of air to be heated) complete with pressure transducer to keep the pressure inside the building balanced
  • Use a balanced extraction/compensation system applied to the preparation zones, with zero pressure balance.

Solution 1: increase the air-conditioning potential and capacity of the building’s existing system

This solution is suitable for small and constant amounts of fresh air. AHUs for room air conditioning work mainly in recirculation with small volumes of fresh air. Of course, the data must be taken into account when designing the AHU as it is not possible to change the configuration once it is installed. The customer must be aware of his requirements and the cost of implementation from the outset.

Rinnovo aria carrozzeria con UTA

Solution 2: compensate the extracted air with a heat generator

Integration with an ErP/Ecotech hot air generator is the optimal solution in the case of already installed air conditioning AHUs on which it is not possible to significantly vary the operating parameters or where the existing preparation zones cause pressure and temperature variations. The advantage of this solution is that you can solve a difficult situation without heavily modifying the building, even if the preparation zones will be used in recirculation mode.

Rinnovo aria con generatore di calore

Solution 3: balanced extraction/compensation system applied to the preparation zones

This solution involves the installation of a system with a zero balance of incoming and outgoing air, complete with heating and/or air conditioning, but above all the possibility of installing energy efficiency systems such as inverters, heat recovery and PLC regulation. The main advantage of this solution is the possibility of installing a unit for several work zones, varying the air flow rate according to their use. This mode works in total Make-up Air with a considerably reduced energy cost using inverters and heat recovery.

Rinnovo aria carrozzeria con gruppo termoventilante

Size, configure and install your fresh air system to perfection

Our keywords are eco-efficiency, safety, planning and conscious choice.

Specialists in air treatment. Business in action!

To achieve the best result, it is important to rely on a partner who can follow the entire design process, evaluating the installation requirements and advising the customer on the solution with the best cost/efficiency ratio of the system. Blowtherm is always at the side of the customer and the consultants involved, even on site, to find together the most technologically correct and economically efficient solution. We know how to combine production requirements, the characteristics of the installation site and the external conditions of the project.