How Professional Evaporative Coolers Work?
Evaporative coolers are an essential part of modern cooling technology, especially in industrial and other large-space cooling applications. Their advantages include energy efficiency and environmental friendliness compared to traditional air conditioning systems. This article examines the operating principle, applications, and benefits of evaporative coolers, as well as the technical aspects to consider when using them. Operating Principle of Evaporative Coolers Evaporative coolers utilize the evaporation process of water to cool the air effectively. This is based on a physical phenomenon where water evaporates and absorbs heat energy from the surrounding air, leading to a decrease in air temperature. Humidification and Heat Transfer Water evaporates when exposed to an airstream, and this process absorbs heat from the air, cooling it down. Coolers use special pads designed to maximize the surface area for water evaporation. These pads are often made of cellulose or plastic, which are hygroscopic and provide a large evaporative surface. Air flows through the pads via a fan, where it encounters water. The water evaporates, absorbing heat energy from the air, thus cooling it. Energy Consumption and Efficiency The energy consumption of evaporative coolers is significantly lower compared to traditional mechanical cooling systems because the process uses natural water evaporation and does not require substantial amounts of electrical energy. The efficiency of these systems depends on the ambient temperature and humidity. They work best in dry and hot conditions where the air’s moisture content is low, as this makes water evaporation most efficient. Operational Principle Adiabatic Cooling: Air is cooled through an adiabatic process where its temperature drops as it becomes humidified. This means that the air’s thermal energy is used for water evaporation without an external energy source. Ventilation and Pressure: In the cooler, air passes through the pads via a fan. The air flowing through the pads encounters moisture that evaporates and cools the air. The fan’s role is critical as it ensures sufficient airflow through the pads and guarantees uniform cooling. Water Circulation: In evaporative coolers, water circulates continuously. Water is pumped to the top of the pads, from where it flows down and evaporates due to the airstream. The recirculation system ensures even water distribution and optimizes the cooling process. Applications in Professional Use Evaporative coolers are widely used across various industries and other large-space cooling applications where efficient and cost-effective cooling is needed. Industrial Facilities Metal Industry: In hot factory halls where temperatures can rise extremely high, evaporative coolers provide an efficient cooling solution that helps keep the working environment tolerable and safe. Automotive Industry: Assembly lines and paint shops in car factories benefit from a cooler working environment, which improves worker efficiency and reduces errors. Food Industry: Evaporative coolers are ideal for cooling large storage and production areas where temperature control is critical to maintaining product quality. Data Centers Data centers require continuous and efficient cooling to prevent equipment from overheating. Evaporative coolers offer an energy-efficient alternative that can significantly reduce cooling costs in data centers. Using adiabatic cooling, data centers can also reduce their carbon footprint, which is increasingly important as environmental regulations tighten. Agriculture Greenhouses: Evaporative coolers help maintain optimal growing conditions, improving crop yields and growth rates. Cooler air reduces plant stress and enhances their resistance to diseases. Animal Shelters: Animal welfare improves in cooler conditions, leading to better health and productivity. This is especially important during the summer months when heat stress can negatively affect animal well-being. Advantages and Challenges Evaporative coolers offer many advantages. Advantages Energy Efficiency: Evaporative coolers use significantly less electrical energy compared to traditional cooling systems because they rely on the natural evaporation process. Environmental Friendliness: Since the system only uses water and air for cooling, its environmental impact is minimal, and the carbon footprint is small. This makes them an attractive option for organizations aiming to reduce their environmental impact. Cost Savings: Lower energy consumption and simple technology mean lower operating and maintenance costs compared to complex mechanical cooling systems. Technical Considerations and Design Portable evaporative coolers are highly convenient and flexible solutions for various professional cooling needs. Their technical design and use require special attention to the following aspects: Components and Materials Pads: The pads are the central part of the cooler responsible for water evaporation. They are often made of cellulose or plastic, providing a large evaporative surface and withstanding moisture and mechanical wear. Fans: Powerful fans ensure sufficient airflow through the pads. The performance of the fans directly affects the efficiency of the cooler. Water Systems: Water systems pump water to the top of the pads, from where it flows down and evaporates due to the airstream. The systems include filters and pumps that ensure water circulation and cleanliness. Device Placement Airflow Control: Optimal airflow and ventilation are essential to maximize cooling. Portable coolers should be placed to draw in as much dry and hot air as possible for the most effective evaporation. Water Source and Quality: A clean and adequate water source is vital for the system’s operation and longevity. Water quality affects the durability and efficiency of the pads and water systems. Considering Portability Durable Construction: Portable evaporative coolers must be durable and sturdy enough to be easily moved to different locations. This means strong frame materials and well-protected components. Practical Wheels: Large wheels enable easy movement of the device and are designed to withstand various floor materials and surfaces. Easy Connectivity: Coolers are easy to connect to electrical and water sources in different locations. They have practical connections and sufficiently long cables and hoses. Impact of UV Light UV light is used in evaporative coolers to improve water quality and prevent bacterial growth. Water Disinfection: UV light kills microorganisms and bacteria in the water, reducing biofilm and slime formation on the pads. This improves the system’s hygiene and reduces maintenance needs. Pad Cleanliness: UV light helps keep the pads free from biological impurities, enhancing their evaporative efficiency and extending their lifespan. Cost Savings: Using UV light reduces the need for chemical cleaning agents and improves the system’s
Why Choose the Rex Nordic HP19 Portable Heat Pump Over a Traditional Heat Pump?
The Rex Nordic HP19 heat pump is an innovative solution that combines portability, efficiency, and ease of use. This heat pump offers unique advantages compared to traditional heat pumps, especially for professional use. Here’s why the Rex Nordic HP19 is an excellent choice for various situations and needs. Portability The Rex Nordic HP19 is designed to be easily portable, meaning you can take it with you as needed. This is especially useful on construction sites where heating or cooling is required in different places at different times. Its portability also makes it an excellent option for events, temporary workspaces, or other short-term needs. This feature allows you to use the device exactly where it’s needed most without the need to purchase multiple fixed units. No Fixed Installation Unlike traditional heat pumps, the Rex Nordic HP19 does not require fixed installation. This means the device can be put into use without major renovations or modifications, saving time and money. It also makes the device more flexible and easier to use in various spaces, such as rented premises or temporary buildings where fixed installations are not possible or desirable. No Electrician Needed Since the Rex Nordic HP19 does not require fixed installation, its setup does not require the assistance of an electrician. This makes the device even easier and faster to use, reducing installation costs. Its simple plug-and-play setup allows anyone to use it without special expertise. Durable Construction The Rex Nordic HP19 is built for heavy professional use. The device is made of steel, not plastic, ensuring its durability even in demanding conditions. This makes it a reliable and long-lasting option. The metal construction withstands impacts and wear well, which is important in industrial environments or construction sites where equipment can face harsh conditions. Components Suitable for Conditions The components of the device have been carefully selected to ensure they suit demanding conditions. This ensures efficient operation and longevity even when exposed to harsh operating conditions. The durability and reliability of the components are particularly important when the device is used in environments where conditions can vary significantly throughout the day. Professional-Grade Air Filters The Rex Nordic HP19 is equipped with professional-grade air filters suitable for dirty environments. Metal mesh filters are washable, making them easy to maintain and extending their lifespan. Additionally, the filters are easily accessible, making their maintenance and replacement straightforward. This is especially useful in places where air filters tend to get dirty, such as industrial plants or construction sites. Effective HEPA Filtration The device also offers an optional highly effective HEPA filtration. This ensures that air quality remains excellent, which is particularly important in production lines and other processes where clean air is essential. HEPA filtration removes fine particles, allergens, and other impurities from the air, improving working conditions and reducing the risk of illness. Precise Air Control With the Rex Nordic HP19, precise air control to the desired target is possible. The device can direct air up to 10 meters away, making it ideal for spot cooling in production lines or various processes. This feature allows targeted cooling or heating, improving energy efficiency and comfort. Moisture Removal The device has an effective dehumidification feature that can remove up to 120 liters of moisture per day. This is particularly useful in damp spaces where excess moisture can cause problems. Dehumidification improves indoor air quality and prevents mold and other moisture-related issues. Condensate Pump An optional condensate pump allows water to be pumped up to 5 meters upwards. This makes the placement of the device flexible and facilitates its use in different environments. Efficient condensate removal is important to ensure the device operates smoothly and without overload. Mobile Control The Rex Nordic HP19 can be conveniently controlled via a mobile app, the same app used for the Airrex heater. This allows for remote use and control of the device, enhancing its usability. The mobile control lets you adjust the device’s settings and monitor its operation in real-time, improving its usability and manageability. Warranty and Spare Parts The device comes with a 3-year warranty that also covers professional use. All spare parts are readily available from stock, ensuring fast and efficient maintenance service. This reduces downtime and increases the device’s utilization rate. A long warranty and good spare parts availability are significant advantages that ensure the device’s longevity and reliability. Summary The Rex Nordic HP19 is a versatile and durable heat pump that offers excellent advantages over traditional heat pumps. Its portability, ease of use, durable construction, and versatile features make it an ideal choice for various applications. Whether it’s a construction site, production line, or other professional use, the Rex Nordic HP19 provides a reliable and efficient solution for all heating and cooling needs. The device is designed to withstand heavy use and demanding conditions, so you can trust its performance and efficiency year after year.
Targeted Cooling in Large Spaces Can Save Up to 30% in Energy
Instead of wasting energy cooling unused areas, targeted cooling focuses specifically on zones that require it, making it a more efficient and cost-effective solution for businesses and industrial facilities. This article delves into the benefits of targeted cooling, explaining why it is the best choice for professional use in large spaces, and how it can economically, environmentally, and practically benefit your company. Energy Savings and Efficiency For businesses, energy consumption is a significant expense, and cooling an entire space consumes much more energy than targeted cooling. Targeted cooling focuses on cooling only the areas where employees and equipment need it, such as workstations, meeting rooms, or specific production lines. Studies have shown that targeted cooling can reduce energy consumption by up to 30% compared to traditional whole-space cooling systems (MDPI). This makes it particularly appealing for large spaces and companies where energy costs can be substantial. Rex Nordic’s mobile air heat pumps and evaporative coolers, known as eco-coolers, are designed to maximize energy efficiency. They can quickly and efficiently cool specific areas, making them an ideal choice for businesses looking to keep energy costs in check without compromising comfort. Environmental Friendliness Companies are becoming increasingly aware of their environmental impact, and reducing energy consumption is a key part of sustainable business practices. Targeted cooling reduces energy consumption and thereby also the carbon footprint. This is especially important for companies aiming to meet environmental standards and improve their sustainability goals. According to a report by the U.S. Department of Energy, targeted cooling can significantly reduce carbon dioxide emissions, particularly in large industrial facilities. Research by the European Environment Agency (EEA) also highlights that targeted cooling is an effective way to meet growing cooling demands while supporting EU energy and climate goals. Convenience and Flexibility Large spaces such as warehouses, production facilities, and office complexes benefit from the flexibility of targeted cooling. With targeted cooling, you can easily focus on the areas that need it most, such as workstations where employees spend most of their time. Rex Nordic’s mobile air heat pumps and evaporative coolers are easy to use and require no installation. Additionally, these devices are portable, so you can use them as needed in different departments or workspaces. Cost-Effectiveness Whole-space cooling systems are generally expensive to install and maintain. Targeted cooling offers a cost-effective alternative. Lower costs and reduced energy consumption make it a financially sensible choice for businesses. Rex Nordic’s products offer excellent value for money. They are durable and long-lasting, meaning the investment will pay off in the long run. Additionally, their ease of use and low maintenance requirements keep operating costs low. Summary Targeted cooling offers several advantages over whole-space cooling, especially in professional use and large spaces. It is energy-efficient, environmentally friendly, cost-effective, and improves comfort and employee health. Rex Nordic’s mobile air heat pumps and evaporative coolers are excellent choices that meet these needs by providing efficient and economical cooling. Consider targeted cooling the next time you look for cooling solutions for your business – it is a wise choice for both business and environmental reasons.
Melting snow and ice with Airrex AH-800 heater
Founded in 1995, Amados Oy is specialised in the marketing and sales of machines related to construction, agriculture and property maintenance in Finland and Russia. The heater Airrex AH-800 was acquired to heat Amados’ workshop hall approximately 2.5 years ago, and it has been in heavy use ever since. Mikkeli-based Amados’ hall is 5–6 metres high and spans approximately 150 square metres, and various working machines are washed there throughout the year. At worst, half a metre of snow may pile up on top of vehicles such as wheel loaders and tractors in winter when they are driven to the hall for washing. “It only takes around three hours to deal with a large amount of snow and ice until it’s all melted away. The heater is in heavy use at that point, but it works superbly,” says Jari Ikonen from Amados. Previously, hot-air blowers were used for heating in Amados’ hall but, according to Ikonen, they were susceptible to becoming dirty. Airrex has no such issues. The diesel-powered infrared heater AH-800 is in continuous use at Amados in the cold season, and 800 litres of fuel is consumed annually. The heater is in heavy use, indeed. READ MORE ABOUT AH-800
Terrace heater, hall heater and BBQ hut heater – Airrex AH-300
Harry Mäkelä has an impressive terrace in his house. Mäkelä uses his grill a lot in winter, so the Airrex infrared heater may be switched on from Friday until Saturday. “We used to use this duct-shaped fuel oil heater. We found its flame and blast slightly dangerous in terms of heating a BBQ hut constructed of log beams with a diameter of 20 cm. A few years ago, when my son acquired an infrared heater and put it by the door of a 200-square metre maintenance hall as a kind of an air curtain, I decided to get these devices for our personal use as well. In temperatures of 20 degrees below zero, we consume around one litre of oil per hour in the BBQ hut. The 2-storey terrace is 17 metres wide and 5 metres deep. One Airrex AH-300 heater is in the lower terrace and one is upstairs. When we had to start refuelling the old heater with fuel oil, the tank of the new heater, in comparison, remains almost half-full,” Mäkelä describes his experiences. In Mäkelä’s experience, an exhaust pipe is not necessary in a big terrace or even in a BBQ hut. The heater does not emit any smoke at all because the oil burns so cleanly. Switching off the heater only causes a small fizzling sound, after which you can smell fuel oil for a while. Mäkelä, however, reckons that the consumption and odour emissions of older Airrex infrared heaters could be reduced if at least their filters were replaced. The heaters have been used for 3–4 years without requiring any particular maintenance. “I can warmly recommend these heaters to everybody, I have been very satisfied with them,” Harry Mäkelä says, summing up his experience. READ MORE ABOUT DIESEL HEATERS
Flower friendly Airrex AH-300 infrared heater solves greenhouse heating problem
Three years ago, at the Munkkivuori Garden, it was considered how the premises would be kept warm and the flowers happy. The gas heater didn’t work, but the diesel-powered Airrex AH-300 was chosen as the right heating solution. The garden has a smaller store section and a larger greenhouse. The entire space is about 5 meters wide and 30 meters long. Initially, they purchased one heater, but very quickly they bought another to the store section. The product has been very easy to use and working perfectly. Now the company has even bought a third heater. – We have been very pleased with these infrared heaters. Two of them are constantly in use and the third is used when needed. On the greenhouse side, the heat is kept at just under ten degrees Celsius and then at the store again at 13-14 degrees Celsius, says store manager Aki Lahtinen. ”Cost-wise, I can say that Airrex is much cheaper than gas heaters” The AH-300 has a charm of comfort and the flowers are happy. The device is almost odorless and produces carbon dioxide, which is great in such an environment. The 15kW / h heating output is just optimal and the low fuel consumption has brought the desired cost efficiency. Workers do not have to worry about using the equipment, just refuel and let the heater do its job. – Yes, these are easy to use, all you have to do is refuel. In terms of cost, I can say that it is much cheaper than gas-fired heaters, says Lahtinen. The Airrex AH-300 has many things that make it easy to use in such spaces. It can be easily moved and does not require a separate exhaust pipe. It is almost odorless and does not make any noise. Infrared radiation heats the material instead of the air. No fan is needed so dust or other contaminants do not rise from the floor. All in all, the Garden has been very satisfied with Airrex heaters. The thermostat-controlled heater is set at the desired temperature and then everyone can concentrate on the essentials. Read more about AH-300
Airrex AH-300 helped cut a garage’s costs significantly
Two years ago, Riku Turunen from Kontiolahti was considering the heating costs of his industrial hall. It consumed a lot of power and the bills really reflected that. Things had to change in a sensible manner. Riku’s garage hall is 135 square metres in size, and the highest point of the roof is at four metres. The large roll-up doors are prone to waste heat, so the task was a challenging one. Airrex AH-300 was selected as the heating device. AH-300 is an almost odourless, diesel-powered infrared heater with a 100% efficiency that is very well suited for industrial halls such as Turunen’s garage. Practice showed instantly that Airrex was a great solution because the device was easy to use as well as cost-efficient. “I must say that over the past two years, I’ve noticed how reliable and easy this device is to use. It’s mainly been in one place, and I’ve had no need to do anything to it although I’m using it all the time.” Besides convenience, savings are playing an important role now. “Earlier, if a period of, say, three weeks incurred an expense of a little more than €680, now I’m only spending €370, fuel included. Annually, that’s quite a big sum of money,” Turunen ponders. Once again, all that was needed was one device to solve issues. Airrex AH-300 reduced heating costs, and Riku Turunen can now focus on the essential – conducting his business – without any worries. READ MORE ABOUT AIRREX AH-300
Moisture and diesel infrared heaters
When heating cold spaces, the moisture tends to condensate on windows, metal structures or other structures in the heated space. From where does this moisture actually come? As a rule, air contains humidity in the form of water vapour: the hotter the air, the more humidity there is in it. Cold air cannot hold as much moisture as warm air. Air that contains water vapour heats up quicker than solid structures. Warmer air gathers more water vapour, but the solid structures in the heated space remain cool. The air close to the structures cools down, and the amount of water vapour in the air exceeds 100% RH. When the relative humidity of air exceeds 100%, water vapour in the air starts to condensate into droplets visible particularly on windows and metal surfaces in the heated space. You can also witness the same phenomena on a frosty pint of beer on a terrace in the summer. Two measurement units for humidity The amount of water vapour in the air, or humidity, is described by two different concepts. One expresses the amount of water in the water vapour found in a cubic metre of air. This is referred to as absolute humidity. The other, relative humidity, expresses the percentage of water vapour contained in the air. Relative humidity may vary from totally dry air (0%) to saturated air (100%) that contains the maximum amount of water vapour possible. Oil heaters produce carbon dioxide and water vapour Airrex infrared heaters burn diesel or fuel oil extremely efficiently, using almost 100% of the energy contained in the oil for the heating of the space. In practical terms, this means that all of the 10 kW of (heat) energy contained in a litre of fuel is utilised. 10-kW heating capacity is enough to significantly raise the indoor temperature in most heated spaces. Once the desired working temperature has been achieved, Airrex heater’s thermostat steps in to control the heater, reducing fuel consumption and emissions. A litre of fuel or diesel oil burnt creates 2.7 kg of carbon dioxide and 560 grams of water. Heating dries the air The capacity of air to hold water vapour is almost directly proportional to the temperature of the air. The colder the air, the smaller the amount of water vapour it can contain. This explains why heating is the most effective way to dry out spaces. Even then, formation or entry of humidity from outside the heated space must be prevented. If the relative humidity in a largish hall space is 40% at 0 degrees Celsius, each cubic metre of air in the space contains 1.9 grams of water vapour (water). If additional humidity is prevented from entering the space, raising the temperature in the space from zero to +20 degrees Celsius reduces relative humidity to five (5) per cent. It does not take much to heat air The average heat capacity of air is 1.01 kJ/kg/°C, based on which it is possible to calculate the output needed to heat it. To raise the temperature of one cubic metre of air by one degree, you need approximately 0.00035 kWh of heating power. If the heated space is, for example, 300 m3 in size, the power required to heat the air in it from zero degrees to +20 degrees is just 2.1 kWh. In reality, however, the above figure is not enough because of the significant effect the structures and objects in the heated space have on the required heating capacity, not to mention any heat loss due to structural leaks and ventilation in the space in question. Humidity created by an oil heater is not a risk The fact of the matter is as follows: to heat a 300-cubic-metre space from zero to +20 degrees, you require about 10 kWh of power, or one litre of oil, at maximum. This translates into 560 grams of water vapour that is mixed with 300 cubic metres of air. The amount of water in each cubic metre of air is, then, increased by about 1.9 grams. If the initial amount of water vapour per cubic metre of air in the heated space was 1.9 grams, the figure after the heating would be approximately 3.8 grams. At +20 degrees Celsius, this translates into about 30% relative humidity, which will not cause a moisture damage risk to any structure whatsoever. Unique benefits of oil-fired Airrex infrared heaters Radiation heaters do not heat the air as such, but the objects in the way of the infrared waves. Thus, the structures and objects in the heated space will become warm quicker than the air. This efficiently prevents condensation of humidity in the air on the surfaces, minimising the risk of damage due to moisture. Another factor that reduces the moisture risk is fuel. Many infrared heaters use liquefied petroleum gas, or LPG, which, when burnt, produces carbon dioxide and water. It is, therefore, a very clean fuel. Airrex heaters are in practice just as clean, but they produce considerably less water than LPG heaters. One (1) kg of LPG produces approx. 12.8 kWh of energy when burnt. At the same time, 2.99 kg of carbon dioxide and 1.63 kg (1,630 grams) of water vapour are produced. Using diesel oil, the amount of water vapour produced to achieve the equivalent heating power is approx. 720 grams – less than half of that with LPG. This is a significant difference, at least for anyone wishing to minimise the risk of moisture damage. Infrared heat dries out structures As described above, infrared heating increases the temperature of the structures and objects in the heated space rather than the air. This prevents condensation of moisture on the surfaces of the structures. Infrared heaters can also be used to remove humidity in applications such as the drying of moisture damage from concrete structures, for example. If there is moisture in the structures of the heated space from the time of construction or for some other reason, infrared heaters can be used
What makes infrared heaters better than fan heaters?
There are many significant differences between an infrared heater and a traditional fan heater. For instance, instead of blowing, infrared heaters radiate heat. Infrared radiation heats materials, not air. To learn more about infrared radiation, visit, for example, Wikipedia. You can feel the heating effect of an infrared heater even outdoors in windy weather because the heat will get through instead of being whisked away with the wind. The warm air blown from the fan heater will disappear in the wind right out of the heater. Airrex infrared heaters are an excellent choice for, for example, service tasks that have to be performed outdoors, e.g. changing a tyre of a car or repairing machinery (forest harvester, tractor, etc.) in field conditions.
Large space heaters and exhaust management
Not many enjoy the exhaust gases produced from burning diesel or fuel oil. A lot of people have found that the gases cause unpleasant symptoms in the respiratory system, mouth and throat, or even eyes, as the most sensitive people have reported.Exhaust management is not a problem for users of Airrex large space heaters that burn the fuel so efficiently that a separate exhaust outlet to the outside is not needed. If the combustion is incomplete, the exhaust will contain various harmful compounds. Unburnt hydrocarbons, carbon monoxide, various particulates, nitrous oxide and, of course, carbon dioxide. In case of high-quality hydrocarbon-based fuel, such as diesel, it is possible to achieve near-perfect combustion, meaning that the exhaust emissions consist mostly of carbon dioxide that is not dangerous as such, and water in the form of water vapour. Perfect combustion is the reason why Airrex infrared heaters do not require separate exhaust piping. Kymenlaakso University of Applied Sciences (KYAMK) is one of the few institutes in Finland that perform emission measurements. Marko Piispa, leader of the emission measurement unit, recalls that the emissions from the Airrex heaters were low. He does not comment on their safety when used in sealed spaces: this can be determined by studying the guidelines and limit values set out by the authorities. Airrex infrared heaters and exhaust gases According to the Decree of the Ministry of Social Affairs and Health on concentrations known to be harmful (HTP) and the Ministry of the Environment procedure on carbon dioxide levels in indoor air, the maximum allowed concentration of carbon dioxide during normal weather conditions and while the room is occupied is 1,200 ppm. The acceptable exposure limit at workplaces during an 8-hour workday is 5,000 ppm. Correspondingly, the amount of carbon monoxide in the air during an 8-hour workday should not continuously exceed 10 mg/m3. The limit for nitrogen dioxide concentration known to be harmful is 6 ppm, or 11 mg/m3, over 15 minutes of exposure. Operating at full capacity, Airrex AH-300 produces one milligram of carbon monoxide per cubic metre of air, meaning that the recommended limit value would not be reached during 10 hours of working. As heaters rarely operate at full capacity all the time, the maximum working time is much longer. And, if normal ventilation is ensured, carbon monoxide creates no risk whatsoever. Harmless as such, carbon dioxide is, in fact, very important for the human body. According to the emission report by KYAMK, exhaust gases from Airrex AH-300 contain 10% of carbon dioxide that is very quickly mixed with the air in the room space. This is why the carbon dioxide emissions are not considered significant. Nitrogen oxides created when burning diesel and fuel oil are considered hazardous to health. Noteworthy in the emission measurement report of an Airrex AH-300 operating at full capacity is that the nitrogen oxide emissions with biodiesel were 201 mg/m3 while those with regular diesel were 183 mg/m3. If exhaust gas is inhaled directly from the end of an AH-300 exhaust pipe, nitrogen oxides cause more stress on the body than recommended (6 ppm, or 11 mg/m3, 15 min of exposure), but the concentration decreases significantly when the exhaust gases mix with the air in the heated space. As regards an Airrex AH-300 operating at full capacity, the value will remain below the concentration known to be harmful (HTP) determined by the authorities when the volume of the heated space is approximately 200 cubic metres. This translates into a room that is approximately 8 x 10 x 2.5 metres in size. If the ventilation of the heated space is in line with the recommendations, i.e. a complete air change per every two hours, Airrex AH-300 can be used in spaces smaller than 100 cubic metres in size without risk of any health hazards due to nitrogen dioxide. With a capacity of 13–15 kW, Airrex AH-300 warms up such a small space very quickly, after which full capacity is no longer needed. This means less nitrogen oxide emissions and, subsequently, negligible health hazards thereof. Emissions in summary In summary, Airrex infrared heaters do not produce dangerous amounts of carbon monoxide – and no separate exhaust piping is required. The carbon dioxide that is created is no more a health hazard than carbon dioxide normally found in the air. During initial heating in a small space, the level of nitrogen oxides created may rise to concentrations determined hazardous by the authorities. The risk can be reduced by staying away from the (small) space during the initial heating and ensuring normal ventilation thereafter. The risk can be eliminated entirely by leading the exhaust gases outside the heated space. The smaller amount of nitrogen oxides created during the less capacity-intensive continuous heating keeps the level below the concentrations known to be hazardous. In a nutshell: a well-designed diesel heater can achieve such perfect combustion that there is no need for a separate exhaust pipe. After reviewing the calculations, this is also confirmed by Marko Piispa, who performed the emission measurements: “Emissions from the Airrex heater were quite low. They do not present a health risk in a large hall with appropriate ventilation.” Visit our webstore to read more about the safe and efficient Airrex heaters .