Energy Efficiency

Energy efficiency in industries is a practice that aims to optimize energy consumption, reducing energy costs and reducing greenhouse gas emissions. That is to say that energy efficiency, beyond economic savings, allows us to be more sustainable and respectful of our environment.

There are several aspects that play an important role, such as energy management and people’s awareness, but beyond these points, an essential aspect is the improvement of production processes with the implementation of more efficient technologies.

This is where BOIXAC comes in, providing highly efficient heat recovery units, calculated and designed to optimally cover the specific needs of each project and industry either with:

Continuous tube and fin heat exchangers
Helical finned tube heat exchangers
Air heat exchangers
Extraction gas heat exchangers
Submerged heat exchangers
Double tube or concentric tube heat exchangers
Pillow plate heat exchangers
Plate heat exchangers
Cross flow heat exchangers
Plain or smooth tube heat exchangers, without fins
Flat tube heat exchangers, oblong

And combining it with resistant constructions such as:

Steam heat exchangers
Superheated water heat exchangers
Thermal oil heat exchangers
Heat exchangers to produce ice
Heat exchangers without welding
Heat exchangers in a pressurized housing or shell
Direct combustion hot air generators
Air coolers
Heat pumps, air heaters

For more details on energy efficiency and heat recovery solutions in your facilities, do not hesitate to read on and contact us.

Coil for temperature control in wine tank

February 18, 2025February 18, 2025 by Oficina Tècnica

COIL FOR TEMPERATURE CONTROL IN WINE TANK OPTIMIZATION OF TEMPERATURE CONTROL IN CULTIVATION TANKS One of the largest sparkling wine producers has implemented a temperature control system for 23 cultivation tanks with a total capacity of 142,000 liters, aiming to ensure optimal fermentation and maintain the quality of the final product. This project has focused on processes taking place in the so-called yeast farms, two rooms where fermentation occurs over five days at a strict temperature range of 18 to 20 ºC. Composition and process conditions The fluid present in the tanks consists of wine solution, tirage liqueur (a sugar-rich syrup), and yeast. This combination is essential for fermentation, as the yeast converts the sugars in the liqueur into alcohol and carbon dioxide, producing the characteristic foam of sparkling wine. Maintaining the fluid temperature within the specified range is crucial for ensuring controlled, high-quality fermentation. Heat exchanger system with internal coils To achieve this thermal control, heat exchanger coils have been introduced inside the tanks. These coils, made of AISI 316 stainless steel with electropolishing, provide excellent corrosion resistance and ensure maximum hygiene, two essential factors in sparkling wine production. The coils are certified under the MOCA (Materials in Contact with Food) standard, ensuring the materials used meet food safety requirements. CLAMP no need All system components have been custom-designed to perfectly fit the tanks’ characteristics and the client’s needs. A design eliminating the need for CLAMP connections was chosen, reducing the risk of leaks and simplifying system cleaning and maintenance. This tailored approach has also maximized heat exchange efficiency and optimized temperature control throughout the fermentation process. Wine tank heat exchanger coil benefits Implementing this system has provided numerous operational advantages: Thermal Stability: Maintaining a constant temperature within the specified range has been key to ensuring homogeneous, high-quality fermentation. Energy Efficiency: Electropolished stainless steel coils offer optimal thermal conductivity, reducing the energy consumption needed to maintain the proper temperature. Food Safety: Compliance with MOCA standards ensures the quality and safety of the final product. Reduced Maintenance: The absence of CLAMP connections simplifies maintenance and minimizes potential technical issues. BOIXAC, HEAT EXCHANGE SOLUTIONS This project is an excellent example of innovation applied to the wine industry, where precise control of fermentation conditions makes a significant difference in the quality of the sparkling wine produced. Implementing custom systems and high-quality materials ensures not only process improvement but also greater efficiency and sustainability throughout the production chain. Contact us Heat exchange solutions for the food and beverage industry Water coil Water coil that is often used to condition the environment of greenhouses and breeding farms, improving animal welfare. Energy economizer Energy economizer or heat recovery system that allows the reuse of excess energy, for example, from biomass boilers. Finned heat exchanger Finned tube heat exchanger, a temperature control system that optimizes durability even in environments with certain contamination factors.

Economizer for greenhouses

February 17, 2025February 10, 2025 by Oficina Tècnica

ECONOMIZER FOR GREENHOUSES GREENHOUSES AND FARMS An economizer for greenhouses or farms refers to the heat recovery system designed to improve efficiency in an environment where, among other things, crop performance is optimized by controlling temperature, ambient humidity, and CO₂. Within the wide range of implementations, we highlight three main areas: 1. The first block refers to water treatment for the hydroponic growth of tomatoes, lettuces, peppers, strawberries, etc. Hydroponic cultivation allows plants to grow faster and more vigorously thanks to direct access to nutrients. These nutrients are dissolved in a water flow that is distributed to the plants through channels. For proper nutrient absorption, it is important to maintain the water within certain temperature ranges, which is achieved thanks to our finned tubes. This heat exchange system can use spiral fins or continuous fins following the same direction as the tubes, maintaining a homogeneous temperature and optimizing both plant growth and quality. 2. The second block is air treatment through overhead ducts, where BOIXAC provides the finned heat exchangers that condition the air in the greenhouse or breeding farm. These exchangers can include various accessories such as fans, humidity controls, and temperature controls. 3. The third block refers to the technology that enriches the environment, thus increasing photosynthetic activity. We achieve this by reusing the excess energy from exhaust gases through the ECO, AIRY, or GASY heat recovery systems. These thermal exchange units are selected based on primary and secondary fluids; in addition, the materials are also chosen according to the specific needs of each installation. Custom solutions for energy optimization in greenhouses and farms. Heat recovery systems for greenhouses and farms Water coil Water coil that is often used to condition the environment of greenhouses and breeding farms, improving animal welfare. Energy economizer Energy economizer or heat recovery system that allows the reuse of excess energy, for example, from biomass boilers. Finned heat exchanger Finned tube heat exchanger, a temperature control system that optimizes durability even in environments with certain contamination factors.

Heat exchanger

February 10, 2025September 29, 2023 by Oficina Tècnica

HEAT EXCHANGER QUESTIONS AND ANSWERS The heat exchanger answers provided below are strictly for guidance and should not be considered as definitive technical advice. To ensure correct and safe application, it is essential to contact our technical office, where qualified professionals will advise you based on your specific needs. BOIXAC assumes no responsibility for any misuse or misinterpretation of the information provided here. Always prioritize safety and rely on specialists for any tasks related to our products. What is a heat exchanger? A heat exchanger is a device whose function is to transfer thermal energy from one element to another, cooling and heating. These elements can be gases, liquids or solids and, depending on their characteristics, with the aim of optimizing efficiency in the heat transfer process, the construction of the heat exchangers can vary. What is a heat exchanger for? A heat exchanger facilitates the transfer of thermal energy, cooling and heating different elements among which we can find fluids, gases and solids. This function is especially useful in industrial processes such as drying, pasteurization, evaporation, refrigeration or distillation. Likewise, it also serves to recover residual energy, control ambient temperature and cool engines. What industries use heat exchangers? The thermal treatment of heat exchangers is essential for many of the processes in the energy, food, chemical, sugar, glass, automotive, paper, pharmaceutical, materials drying, textile, oil, gas, metallurgy, data centers and electronics industries. We also find heat exchangers in other areas such as agri-food and tertiary. How does a heat exchanger work? A heat exchanger is characterized by having two sections, in each of which an element circulates that can be fluid, gas or solid. These sections are separated by the thickness of a tube or plate through which heat is transferred from one side to the other without the flows mixing. For thermal energy to be transferred there must be a certain temperature differential between the flows and the selected materials must be conductive. This is why heat exchangers are often made of copper, aluminum, steel, stainless steel, titanium or cupro-nickel, both to maximize the heat exchange coefficient and also to adapt to the different particularities that each element may have. The selection of heat exchanger construction is directly related to the working conditions. What types of heat exchangers are there? Heat exchangers can be manufactured following very different constructions, among which we highlight: 1. Tube exchangers. Heat exchanger with smooth tubes, without fins. Heat exchanger with tubes and continuous fins. Heat exchanger with tubes and helicoidal or spiral fins. 2. Plate exchangers. Pillow plate heat exchangers. Cross flow plate heat exchangers. Removable plate heat exchangers. Welded plate heat exchangers. 3. Multitubular exchangers. Double tube heat exchangers or concentric tubes heat exchangers. Tube and shell heat exchangers. What is the efficiency of a heat recovery unit? A heat exchanger is a passive device, meaning that it does not generate heat or cold by itself. The same design can offer different levels of efficiency depending on the conditions with which we make it work. Among the working conditions we find concepts such as the typology of fluids, flow rates, temperatures, absolute humidity or fouling factors. Once the user has defined the objective, for example, reaching a certain power or a certain temperature at the fluid outlet, the technical office has the objective of finding the construction that optimizes the efficiency of the heat exchanger. Where can we buy a heat recovery unit? Since each facility has its own singularities, in order to optimize the efficiency of each installation, heat exchangers must be custom designed and manufactured. This is why we recommend contacting a specialist who will guide you in the selection and acquisition of these devices. We encourage you to visit our website and contact us, our technical office highly specialized in heat exchangers will guide you. How can I choose the right equipment? To choose the right heat exchanger, it is essential to consider several factors, including the inlet and outlet temperatures of the fluids, the flow rates of the fluids involved, the type of fluids and their characteristics (viscosity, corrosiveness, fouling, etc.), access, space, and installation constraints, as well as maintenance and durability requirements, among others. Its complexity requires contacting a specialist like the experts at BOIXAC to guide you and ensure the design is properly tailored to your needs. What maintenance does a heat exchanger require? Regular maintenance is crucial to ensure optimal performance. The most common steps are: periodic cleaning to remove fouling and deposits that reduce efficiency, inspections of gaskets and components to detect possible wear or damage, especially in critical parts, replacement of worn parts to avoid operational failures, and pressure tests to ensure there are no leaks or structural weakening. The maintenance frequency will depend on the process conditions and usage. What is fouling, and how does it affect performance? Fouling refers to solid deposits that accumulate on the surfaces of the heat exchanger due to sediments, minerals, or other particles present in the fluids. This phenomenon can reduce heat transfer, increase energy consumption, and/or cause premature wear of the system. Prevention through filters and regular cleaning is essential to minimize these effects. How can I detect and prevent leaks in a heat exchanger? Leaks can be caused by worn gaskets, corrosion, or mechanical damage. To prevent them, it is advisable to perform regular visual inspections, implement pressure or temperature sensors to detect anomalies, and use corrosion-resistant materials in systems handling aggressive fluids. If in doubt, always contact our technical team. What are the signs of heat exchanger malfunction? The most common indicators of malfunction are: a drop in thermal efficiency (fluids not reaching the desired temperature), increased pressure loss, visible fluid leaks, strange noises, or vibrations during operation. If in doubt, consult a qualified technician. Can a heat exchanger be customized? Yes! We offer customization options to meet specific needs, such as special materials, unique dimensions, or configurations for unusual fluids. A tailor-made heat exchanger ensures the best results under specific … Read more

Heat exchangers in the energy industry

February 17, 2025February 1, 2023 by Oficina Tècnica

ENERGY INDUSTRY HEAT EXCHANGERS FOR ENERGY OPTIMIZATION Heat exchangers are a very important product in the optimization of energy transformation processes, whether in thermal power plants, nuclear power plants or hydroelectric power plants, among others. Let’s dive deeper into the uniqueness of each of these systems below: 1. In thermal power plants, heat exchangers are used to transfer heat generated by fossil fuels such as coal, oil or gas to a fluid such as superheated water or steam. This fluid reaches high pressures and drives a turbine that generates electricity. As the fluid drives the turbine, it cools and we condense it using a new heat exchanger we call a condenser. Once condensed, we reuse the fluid to heat it with fossil combustion and generate energy again. In thermal power plants we could find cogeneration plants which, in addition to producing heat, generate electricity, as well as trigeneration plants, which, in addition to producing heat and electricity, generate refrigeration energy, which means greater energy efficiency and sustainability. 2. In nuclear power plants, heat exchangers are essential to control the temperature of the reactor with the help of a coolant. The heat transfer fluid absorbs the heat and transmits it to a steam generator which will convert the energy into electricity. This coolant, once cooled, will return to the start to start the process over. Beyond this aspect of operation, heat exchangers are also used as a preventive measure in diesel engines with the aim of controlling a possible electrical shutdown. There are many other models of energy generation, all with very particular singularities that we will analyze in other articles. Beyond the explanatory brushstrokes we have made, all projects require in-depth analysis and a highly experienced professional team. If you have any needs, contact us, we are at your disposal. Heat recovery for the energy industry Gas heat recovery Heat recuperator that economizes with the use of exhaust gases from boilers, turbines or combustion engines used for example in cogeneration. More efficiency and less emissions. Counter flow heat exchanger Cross-flow heat exchanger, usually between a stream of fumes or gases and another of air, without them mixing. With a design that is easy to clean and maintain. It is ideal for the energy, oil and gas sector. Steam heat exchanger Coil of tubes designed to convert saturated or wet steam into dry, superheated steam, usually by steam turbines for electricity generation. They can withstand temperatures of up to 950ºC.

Heat exchanger to produce ice

February 17, 2025October 3, 2022 by Oficina Tècnica

HEAT EXCHANGER TO PRODUCE ICE The heat exchanger to produce ice is a deferred cooling system that allows the production, accumulation, and storage of ice during hours of lower energy demand, when energy costs are often lower. This intelligent cooling system stores this cold source for use during periods of higher energy demand, when energy costs are often higher. This heat exchanger is especially interesting for industries that require advanced cooling systems and in countries where energy rates may fluctuate, for example, between daytime and nighttime energy consumption. ICE ACCUMULATOR TO SAVE ENERGY Beyond the significant operational energy savings of the cold accumulators, the cost of implementation should also be mentioned. Some production processes and large conditioning systems require significant amounts of cooling. Traditionally, this involves the need to install high-power refrigeration equipment with the corresponding purchase, energy, and maintenance costs. By incorporating these systems as an additional cooling source, we are able to size industrial chillers, cooling towers, and dry coolers smaller, which reduces not only energy and maintenance costs but also acquisition expenses. Among the products that could be especially interesting for this application are: 1. Pillow plate heat exschanger. 2. Smooth tubes heat exchanger. 3. Cooling jacket. 4. Ice producer.

Industrial economizer

February 17, 2025June 1, 2022 by Oficina Tècnica

ECONOMIZER HEAT RECOVERY SYSTEM IN AN INDUSTRIAL BOILER In the context of industrial production, energy efficiency is a key factor in reducing operating costs and minimizing environmental impact. Industrial boilers are essential for many processes, such as steam generation, water heating, or thermal oil heating. One of the key components that improve the efficiency of these boilers is the heat economizer or heat recovery system. This device allows for the recovery of thermal energy from exhaust gases that, without this technology, would be lost. In this article, we will explore how an economizer works in a two-pass industrial boiler, using a heat exchanger to efficiently transfer thermal energy to fluids such as steam, superheated water, or thermal oil. What is an economizer? An economizer is a device that recovers the residual heat from the exhaust gases of a boiler to heat the feedwater before it enters the boiler. This way, the system increases the thermal efficiency of the boiler and reduces fuel consumption. The principle of operation of an economizer is based on the use of a heat exchanger that transfers thermal energy from the combustion gases to an incoming fluid, usually water or another thermal substance. This way, the feedwater reaches the boiler at a higher temperature, reducing the amount of energy required to heat it to its final use. How an economizer works in a Two-Pass Industrial Boiler Two-pass industrial boilers, also known as double-pass or double-circuit boilers, have a structure designed to optimize the heat transfer of combustion gases. This type of boiler is designed to maximize the utilization of exhaust gas energy by using two circuits of gas flow. In this context, the economizer is installed in the first pass of the exhaust gases before passing through the boiler heat exchanger. Exhaust gases and heat exchanger: When fuel is burned inside the boiler, the generated gases have a very high temperature. The gases exit the boiler and circulate through the first circuit, passing through the economizer. This is where the heat recovery system takes advantage of this residual heat to transfer it to the feedwater through a steam or water heat exchanger. Heat transfer: The heat exchanger used in the economizer can be a steam heat exchanger, a superheated water heat exchanger, or even a system designed to heat thermal oil. Each of these systems uses a similar principle: the exhaust gases transfer their heat to the circulating fluid, raising the temperature of the feedwater before entering the boiler. This allows the boiler to use less fuel to reach the required temperature to generate steam or heat other thermal fluids. Energy efficiency improvement: The feedwater, once heated thanks to the economizer, enters the boiler at a higher temperature. This means that the boiler will need less energy to heat it to the desired operating temperature. This fuel saving directly translates into a reduction in operating costs and a greater environmental sustainability for the plant. Economizer design and materials: To ensure efficient heat transfer, industrial economizers are often made from materials resistant to high temperatures and corrosion, such as stainless steel or special materials for extreme operating conditions. These materials ensure that the devices have a longer lifespan and are efficient under demanding working conditions. Types of economizers used The design of the economizer depends on the type of fluid to be heated and the specific conditions of each industrial plant. Below are the most common types of heat exchangers used: Steam heat exchanger: In some cases, the boiler needs to generate steam for industrial processes. A steam heat exchanger allows the use of exhaust gas energy to raise the temperature of the water before it reaches the boiler, thus facilitating steam production with less energy. Superheated water heat exchanger: When it is necessary to heat water beyond its saturation temperature, a superheated water heat exchanger is used. This system keeps the water in a superheated state for specific industrial applications, such as heat production or energy generation. Thermal oil heat exchanger: For industrial processes that require heating at high temperatures, thermal oil is a popular option. Thermal oil heat exchangers are specifically designed to transfer heat from exhaust gases to the oil, allowing the system to maintain a constant and efficient temperature throughout the process. Advantages of using an economizer Among the many advantages offered by the use of Economizers and Heat Recovery Units, we can highlight: Reduction in fuel consumption: One of the main advantages of installing an economizer is the significant reduction in fuel consumption. By recovering residual heat, less energy is needed to reach the desired operating temperature. Increase in overall efficiency: Thanks to the recovery of residual heat, the overall efficiency of the heating system significantly improves, which contributes to a smaller carbon footprint. Economic savings: Operating costs decrease since the boiler requires less fuel to generate the same amount of steam or heat water. Sustainability: Reducing fuel consumption not only provides economic benefits but also contributes to sustainability by minimizing the environmental impact of industrial operations. In this sense, economizers or heat recovery systems in two-pass industrial boilers are essential components for improving energy efficiency and reducing operating costs in industrial processes. By using steam, superheated water, or thermal oil heat exchangers, the thermal energy from exhaust gases can be used to heat fluids such as feedwater. This way, a more efficient and sustainable system is achieved, contributing to resource optimization and reducing environmental impact. BOIXAC, A WORLD OF INDUSTRIAL ENERGY RECOVERY We have a wide range of different technologies, including smooth tube heat exchangers, finned tube heat exchangers, and pillow plate exchangers. This constructive variety allows us to customize the solutions we propose, adapting to the reality of each production process and thus optimizing the thermal resources available at each plant. Our advanced technical knowledge enables us to offer a range of economizers and heat recovery systems capable of working with combustion gases below their dew point, thus allowing condensation and recovery of acidic condensates from the gases themselves. … Read more

Air treatment filters

February 17, 2025October 1, 2021 by Oficina Tècnica

AIR TREATMENT FILTERS CLASSIFICATION OF AIR FILTERS Filters for air treatment are essential to maintain its quality and take care of the health of living beings. Just as we give special importance to the food and drinks we consume, it should be noted that humans breathe close to 0.7 kg of air per hour, thus becoming a vitally important factor for our well-being. Air is made up of particles (salt, pollen, fibers,…) and gases (N2, O3, O2, CO2, SO2,…), often imperceptible to the human eye, which can have different characteristics such as weight, size, speeds, etc. Although our respiratory system filters these particles, as they are smaller they enter our body more easily, for example particles of 10 µm would stay approximately in the respiratory passages, while particles of 2, 5 µm would reach the lungs, 1 µm particles could enter the bloodstream and 0.1 µm particles could cross the cell membrane. According to information provided by Camfil at Pharmaceutical Solutions Day, 99.9% of airborne particles are less than 1 µm in diameter and, as published in the ASHRAE Handbook, in these sizes of particles we would find diesel particles, oil fumes, tobacco fumes, asbestos and bacteria, among others. Therefore, its control is essential especially in fields such as health, the food industry or the pharmaceutical industry. Next we find the synthesized classification of the different filters according to ISO 29463 and the EN 1822:2009 standard: Grup Class EN1822 & EN16890 Class ISO29463 Application Integral value Local value % effic. % pen. % effic. % pen. PRE G1 – Pre-filters insects, fibers, dust, sand n/a n/a – – PRE G2 – Pre-filters insects, fibers, dust, sand n/a n/a – – PRE G3 – Pre-filters insects, fibers, dust, sand n/a n/a – – PRE G4 – Pre-filters insects, fibers, dust, sand n/a n/a – – – M5 – Workshops, factories, warehouses n/a n/a – – – M6 – Offices, warehouses, pre-filters E10 & E11 n/a n/a – – – F7 – Data centers, hospitals, pre-filters H12 to H14 n/a n/a – – – F8 – Data centers, hospitals, pre-filters H12 to H14 n/a n/a – – – F9 – Data centers, hospitals, pre-filters H12 to H14 n/a n/a – – EPA E10 – Food, pharmaceuticals 85 15 – – EPA E11 ISO 15 e 20 E Food, pharmaceuticals 95 5 – – EPA E12 ISO 25 e 30 E Food, clean rooms 99,5 0,5 – – HEPA H13 ISO 35 e 40 H Sterile environments, nuclear, pharmaceutical 99,95 0,05 99,75 0,25 HEPA H14 ISO 45 H e 50 U Electronics, pharmaceuticals 99,995 0,005 99,975 0,025 ULPA U15 ISO 55 e 60 U Electronics, pharmaceuticals 99,9995 0,0005 99,9975 0,0025 ULPA U15 ISO 55 e 60 U Electronics, pharmaceuticals 99,99995 0,00005 99,99975 0,00025 ULPA U17 ISO 75 U Laboratories, pharmaceuticals 99,999995 0,000005 99,9999 0,0001 One of the characteristic factors of air filters is that since it is an element located in the middle of the air flow (within HVAC systems, Air Treatment Units, impulse boxes, extraction boxes of ‘air or air purifiers), involve a load loss that, with a greater degree of filtering, this can increase considerably with the consequent energy cost. For this reason, the selection of the type of filter, beyond effectiveness, must also be assessed in terms of efficiency, resistance and useful life. Contact us and we will help you select your filtering system.

Industrial heat recovery

February 17, 2025June 1, 2021 by Oficina Tècnica

INDUSTRIAL HEAT RECOVERY THE GREENEST, OPTIMAL AND SUSTAINABLE ENERGY BOIXAC had the honor of being invited and participate in the podcast Con G de Geo, which aims to bring engineering closer analyzing concepts such as industrial heat recovery, sustainability, through renewable energies, energy optimization and the efficient use of our resources. You can read the trasncription of our contribution below and we encourage you to listen to us through the following link. “In December 2019, the European Green Deal was approved, which aims to achieve climate neutrality by 2050. To do this, a scale was made with the different actions to be carried out and, one of the steps on which we will stop and we will analyze if we have done our job is in 2030. In addition to aspects such as recovering biodiversity, improving animal welfare or promoting sustainable forest management, there are three aspects that directly influence the field of energy: – Establish a minimum share of renewable energies of 40%. – Improve energy efficiency by 36-39%. – Reduce greenhouse gas emissions by 55%. All these aspects are important to find a solution to the climate emergency but, at BOIXAC, we understand that if the world population continues to increase, for example, only in Spain an increase of 2% in the next 15 years is prevented, beyond the use of renewable energies, sustainability goes through the change in consumption habits and the optimization of our resources. In this sense, considering that the Spanish industry consumes about 31% of total energy, its modernization and optimization is one of the keys to our future. When we go along the highway, as far as the eye can see, we see factories that need energy for their processes, for instance to heat wastewater and facilitate the biological digestion of sludge, dry cement for its correct conservation, increase CO2 in greenhouses to increase the rate of photosynthesis, cool foods such as chocolate for modeling, etc. All processes that need to heat or cool require energy, and energy maintains a balance. In fact, heat is the transfer of energy from an area of high temperature to another area of lower temperature. If, for example, we look at what happens in our homes when we turn on the air conditioning, we will see this balance. While the indoor unit blows out cool air, the outdoor unit blows out excess heat. Starting from this energy balance, we see that a certain renewal of the indoor air is needed to maintain its quality. For this renewal we take the outside air and cool or heat it depending on each need. At the same time that we introduce the new air, we must expel the excess air from the interior so that the new one can fit and this is where we come in with heat recovery. If we make a leap from our homes to the industry and imagine, for example, that the outside air is at 20ºC and we want to heat it so that it reaches 80ºC inside, for example, in a dryer where we need to extract moisture . Here we apparently need equipment that is capable of increasing the air temperature by 60ºC, from 20 to 80ºC. However, there is another option that is smarter, cheaper and more sustainable. When we take this air from the outside at 20ºC and we want to heat it to introduce it into a room, the same flow of air that was inside at 80ºC will be expelled. By means of a heat recovery system we make these two air flows cross each other without mixing through a system known as cross flows. We do not mix these flows in order to maintain the quality of the previously filtered air, but we do extract the heat from the outgoing air flow and transfer it to the incoming air flow. With this system we achieve two objectives; 1. The cold air that we are introducing will rise in temperature, so that the equipment we use to heat it, often boilers, will be able to work more relaxed, consuming less energy and, therefore, saving and being more sustainable. 2. The hot air that we are expelling will significantly lower its temperature, resembling the ambient temperature and, therefore, we will be even more sustainable. The technology of heat recovery units may change depending on the application and the manufacturer, but, as we have seen, it is based on perfecting the filters to offer correct air quality, and the fans to obtain air circulation. the lower electricity consumption and the energy recuperators that are the heart that allow the magic of heat exchange. Here you can add other added values such as control or isolation. In our particular case, from BOIXAC, we specialize in industrial heat exchangers and, just as it is important to work to improve ventilation and filtering techniques, exchangers also progress to offer solutions resistant to corrosive environments, high pressures and temperatures. up to 950ºC, with flattened tubes to reduce pressure losses and compact constructions that currently reach efficiency levels of over 80%. In the industrial field, applications have many singularities such as fluids, viscosities, pressures, temperatures, materials, fouling coefficients, etc. That is why each project is studied in detail to optimize its construction and thus achieve the objectives of energy efficiency, sustainability and savings necessary for industrial progress.”