Some of the most frequently asked questions about air conditioning
Air conditioner or air-conditioned? *
The term ‘air conditioner’ refers to an air conditioner unit, the object itself. The term ‘air-conditioned’, refers to air that is conditioned because its temperature has been regulated by a specific device. Therefore, air conditioner = air conditioning equipment.
*In Brazilian Portuguese these terms are spelled in the same way. The term ‘ar-condicionado’ is translated into English as ‘air conditioner’. The term ‘ar condicionado’ is translated into English as ‘air-conditioned’. In Portuguese, it is important to note the use of the hyphen in order to give the correct meaning.
How does an air conditioner work?
Air conditioners climatize, which means they “change” the temperature of the indoor environment, causing it to be lower (by cooling, which is its more common use in Brazil) or higher (by heating), depending on the weather, the type of equipment and the chosen function.
For this temperature change to happen, the air is drawn from the environment by a fan and forced to pass through a set of sealed tubes and metal plates. These tubes form a closed circuit and inside it circulates a fluid which – according to the laws of the physics – becomes cold when subjected to low pressure, and hot when subjected to high pressure.
Through the action of a compressor (which increases the pressure) and a valve (which reduces the pressure), installed at different points of this pipe circuit, the fluid circulates with high (hot) pressure in a part of the circuit and circulates at low (cold) pressure in another part. See the figure below:
When the objective is to cool the environment, air is forced through the cool part of the circuit (called the evaporator) and then driven by a fan into the conditioned environment – while the air circulating through the hot part (the condenser) is forced outside of the building.
In devices that also have a heating function, the air is forced through the hot part of the tubes and then released into the environment. Both the compressor – responsible for pressurizing the fluid – and the fans are powered by electricity. Therefore, the more efficient the air conditioner, the lower its power consumption.
What is inverter air-conditioning?
Currently, the air conditioners available in the market are divided between conventional and those using a more recent technology called an inverter. The difference is in the way the compressor works.
In the conventional type, the compressor operates on only one rotation speed, and is turned on and off by demand to maintain the desired ambient temperature. The control of this mechanism is performed by a component called the thermostat, which measures the temperature in the room and “notifies” the compressor when it should turn on and off. The problem is that turning on the compressor needs a significant amount of energy, causing a so-called “power surge” – which sometimes makes the light bulbs of the house flicker. Have you noticed?
In the inverter type, instead of turning the compressor on and off again, an electronic system reduces and increases its operating regime according to need. In this way, the ambient temperature remains constant, the noise level is lower and there is an energy saving of up to 40% compared to the conventional system. In addition, it is easy to remember: less consumption means less greenhouse gases emissions.
What are the types of air conditioning?
There are several types of air conditioners on the market. The most well-known are as follows:
A – Window – It is installed in an opening in the wall and is more suitable for smaller environments (the larger models are suitable for rooms up to 70 m²). It is compact and the entire system (condenser and evaporator) is located inside a single enclosure.
B – Split – This means separate or divided. The name comes from the fact that, in this type of device, the components are separated into two different units, connected to each other by cables and ducts – one installed inside the environment to be cooled, the other in an external area. The evaporator (the cooling part of the system) is located in the indoors module, while the condenser (the heating part) and the compressor are outside. One of its advantages in relation to the wall models is in the installation, which requires less work: instead of a large opening in the wall, all that is required is a passage for a duct. Another advantage is the silence, because the compressor, which is the main source of noise in this type of equipment, is located outside.
There are several types of split air conditioning that are suitable for different types of installation and sizes of environments. The following are the most common in Brazil.
B1 – Split Hi-Wall – It is the most common type of split conditioner and also the most sold. The indoor unit is installed attached to the wall of the room (so it is also called “wall split”).
B2 – Mini Split – A more compact version of Split Hi-Wall, suitable for the air conditioning of smaller rooms such as bedrooms.
B3 – Window Split – This is an ordinary split, but its condenser unit (external) can be installed in the existing openings for wall air conditioners. This is very useful, for example, in buildings that already have these standardized on the facade or do not allow the installation of ordinary splits. Usually, these are suitable for small environments.
B4 – Multi Split – Similar to ordinary hi-wall models, but allows for the installation of two or more internal evaporator units for each external condenser unit. In this way, with just one device, it is possible to simultaneously cool more than one environment.
B5 – VRF – Variable Refrigerant Flow. This refers to a type of multi-split equipment (see the previous item), where the volume of the refrigerant sent to each of the (internal) evaporator units is adjusted electronically, according to the regulation in the different environments, by inverter technology. It is especially suitable for buildings with a large number of rooms, such as commercial, hospital and industrial buildings.
B6- Split Cassette – In this version, the evaporator unit (which is inside the room) can be installed on the ceiling. There are versions with a capacity of up to 60,000 BTU (for environments up to 100 m²).
B7 – Split Floor-Ceiling – As the name implies, this indoor unit can be installed both on the ceiling and on the floor. It is suitable for large environments.
B8 – Split Ceiling Corner – This differs from the ordinary split because its internal unit is designed to be installed in the corner of the ceiling. Most models are designed for small environments.
C – Portable – Like the window model, the entire system (compressor, condenser and evaporator) is located inside a single enclosure, which makes it noisier than the split model. It can be transported to different rooms or even addresses (it usually comes with small wheels on the base), as long as the room has a small opening to the outside to connect a tube for the hot air discharge. In most models, there is a reservoir for the water produced by the condenser and this needs to be emptied after a certain number of hours. It is indicated for those who want to have only one device that can be used in several rooms/places (at different times, of course) and is also a good solution for listed properties and those in which it is not possible to install any other type of equipment.
D – Central/Duct – Usually used in buildings, large facilities (such as malls) and other places where a large air conditioning capacity is required for several spaces simultaneously. In this case, one or more air conditioning units are installed in external areas, interconnected with the internal environments by ducts, where cooled (or heated) air is driven by high pressure fans. Unlike split models, these devices typically have condensing and evaporating units in the same enclosure.
What is a BTU?
BTU (British Thermal Unit) is the unit used in the air-conditioning field to indicate the ability of an appliance to cool an environment. The more BTUs the conditioner has, the greater its ability to cool the environment. In general, larger environments need equipment with more BTUs to be cooled. In addition to the dimensions, another important factor – especially in tropical countries, like Brazil – is the solar exposure of the external wall (s) of the conditioned environment. The table below shows the relationship between the area and the capacity in BTUs needed to cool it in two different sun conditions.
Why do we have to worry about the energy consumption of air conditioning?
Today, in Brazil, the consumption of air conditioners corresponds to about 17% of all the electric energy consumed by households. There are more than seven million of these devices installed in Brazilian homes and this number has been growing on average by 10% per year. Soon air conditioning will become the main item in the residential and commercial consumption of electric energy in our country.
The problem is that this growing consumption produces energy demand peaks – which are the times of day when there is a more intense use of electrical equipment, requiring more current from the grid. Most of Brazil’s energy generation (about 70%) comes from renewable sources. However, to meet this higher demand, it is often necessary to activate thermal power plants, whose generation is more expensive. For this reason, during these peak times, the rates charged by the energy providers are higher than for the rest of the day. The higher the peak, the greater is its weighting in the electricity bill. In addition, thermoelectric plants pollute – they use fossil fuels (such as natural gas, oil and diesel oil) as fuel and release greenhouse gases into the atmosphere, which are directly responsible for climate change.
It is not only this. More efficient equipment also requires fewer refrigerants, and here in Brazil, the most used are hydrofluorocarbons (HFCs), which are gases that have a very high GWP. Therefore, increasing energy efficiency also reduces the direct emissions of these gases.
Buying more efficient air conditioning equipment, in addition to reducing energy consumption – and the cost of your electricity bill – helps to preserve the planet.
What is the Kigali Amendment?
It is an addendum to the Montreal Protocol – a 1987 international treaty that established that the substances responsible for the destruction of the ozone layer would be replaced by non-aggressive substances from 1989 onwards. The amendment included hydrofluorocarbons (HFCs), which do not destroy the ozone layer but are powerful greenhouse gases and are included in the list of substances in the Montreal Protocol (which are controlled and whose consumption should be progressively reduced). It bears the name of the city of Kigali, in Rwanda, where the meeting in which it was approved took place in 2016 and will take effect on January 1, 2019.
See the original document of the Kigali Amendment , in six languages.
What is EEC?
It is the acronym of the Energy Efficiency Coefficient and indicates the cooling capacity of an air conditioner in relation to its energy consumption, both measured in Watts. The higher the EEC, the more efficient the device.
What are the minimum levels of energy efficiency?
It is the EEC (see item 7) that certain equipment must reach before it can be placed in the market. In Brazil, these minimum levels were established by the National Policy for the Conservation and Rational Use of Energy (Law 10250/2001). This created the Management Committee of Energy Efficiency Indicators (CGIEE), which is the body responsible for establishing the EEC for each category of equipment and machinery. Equipment manufactured in our country and imported equipment must respect them. The body responsible for evaluating the compliance with this rule is the National Institute of Metrology, Quality and Technology – INMETRO, as part of the Brazilian Labeling Program (PBE)
What is labeling?
In order to be sold in Brazil, air conditioners (as well as other electrical equipment) has to be evaluated and approved by INMETRO, commissioned by the Management Committee of Energy Efficiency Indicators (CGIEE) of the Ministry of Mines and Energy (MME). In addition to verifying that the product meets a series of legal requirements, the Institute classifies its performance according to a scale from A to D, where the letter A indicates high efficiency and D low efficiency – which is also the minimum level allowed for the category. The result of the evaluation is indicated on a mandatory label, which is attached to the product to assist the consumer in his choice. This explicitly displayed information also serves to stimulate the competitiveness of the industry and results in the manufacture of more efficient products.
What is the Procel Seal?
The National Program for the Conservation of Electric Energy – Procel was created in 1985 to promote the efficient use of electricity and fight waste. Based on the INMETRO analyses, the program certifies with a special seal the most efficient home appliances available in the market. In practice, it functions as a kind of “energy merit medal” and, like labeling, aims to help the consumer identify more efficient products as well as to stimulate competition between manufacturers.
What is the average energy efficiency of the air conditioners sold in Brazil?
Currently, a split air conditioner (the best-selling) must have an Energy Efficiency Coefficient (EEC) of 2.6 to be included in the lowest D range of the INMETRO classification.
In the case of window type devices, the minimum index for a device with a capacity of up to 9,000 BTU is 2.68.
Unfortunately, the minimum levels of energy efficiency adopted today in Brazil are considerably lower than those used in China, Japan and the European Union, for example. A survey by the Federal University of Santa Catarina (UFSC) showed that while these are around 2.6 W/W in Brazil, in most countries – including nations like India and Mexico – they exceed 3 W/W. (Source SindusCon-SP).
What are the factors that influence the energy efficiency of equipment?
The energy efficiency of an air conditioner is basically related to the technology and the components it uses – such as the type of compressor, fans and refrigerants, for example. For example, an air conditioner that uses updated technology can consume up to 72% less electricity than one with outdated technology.
In addition, the type of equipment – whether it is a split air conditioner (more efficient) or a wall air conditioner (less efficient) – has an influence on its energy performance.
Other important factors include:
– The climate – the warmer the climate, the greater the need for cooling and the lower the efficiency.
– The position of the building in relation to the sun path – rooms exposed directly to the afternoon sun demand more cooling capacity.
– The type of building – aspects such as material, positioning and dimensions of the building and even the type of neighborhood (if there is ventilation or other large buildings, for example).
– The installation – the choice of the most appropriate equipment for each environment for the site and the installation conditions (the distance between the internal and external units, in the case of split models, for example).
– Proper maintenance – the cleaning of filters and ducts and the perfect operation of compressors and fans.
What is EER?
The Energy Efficiency Ratio is an index used to classify the energy efficiency of air conditioners. This index is calculated by dividing the cooling capacity of the equipment, measured in BTU/h (thermal unit per hour) by the amount of energy it consumes over the same period. For example, a 10,000 BTU-capable, 1,200-watt device has an EER of 8.3. (Source: refrigeracao.net)
What is COP?
The Coefficient Of Performance, such as the EER, is an energy efficiency index. However, instead of cooling, it is based on the heat removal capacity (consumption x heat). The higher the COP, the more efficient the equipment.
What is SEER?
The Seasonal Energy Efficiency Ratio differs from the EER because it considers the consumption of the equipment throughout the year – taking into account the different climatic seasons and the different operating regimes of the equipment (higher in summer, for example).
What is GWP?
The Global Warming Potential indicates how much a particular substance contributes to global warming. Its scale is based on the effect of carbon dioxide – CO2, which is assigned a value of 1. Hydrofluorocarbons (HFCs) used as refrigerants in air-conditioning equipment such as HCFC-22 and HFC-410A have a GWP two thousand times greater than that of CO2.
What is the citizen's role in increasing the energy efficiency of air conditioning?
The consumer is a protagonist in the search for products with better energy efficiency standards and cannot behave passively. The consumers represent, with their purchasing power, the ability to choose – and to refuse inefficient equipment – the main agent of market transformation. The consumer’s main weapon is information. Before buying an air conditioner, the consumer needs to know what type and capacity of equipment is most appropriate and where it will be used. More than just looking at the lowest prices, one must consider the reputation that brands and models have in the market and how much energy the different available models/brands consume and what their impact is on the environment. There are websites and consumer associations where there are comments, testimonials, articles and tips on the subject, such as the IDEC. Often, a small price difference at the time of purchase may turn out to be more expensive electricity bills in the future. A conscious consumer thinks in the medium and long term and not only saves money, but also contributes to higher productivity, the lowering of costs of the entire electrical system and the reduction of greenhouse gas emissions and atmospheric pollutants.
What is the role of the state in advancing energy efficiency in the air conditioning field?
It is up to the state to define national energy efficiency policies, guide and set market targets, set timetables for changes to be made, and oversee compliance with the rules. It is these goals that will tell the industry what investments to make in their product lines to meet the new requirements.
The government has given the responsibility to the Management Committee for Energy Efficiency Indicators (CGIEE), of the Ministry of Mines and Energy (MME). In order to establish the minimum levels of efficiency for products authorized for sale in Brazil, the CGIEE has technical committees that involve representatives from civil society (industry, universities and consumers).
What is the role of industry in advancing energy efficiency in air conditioning?
It is up to the industry to offer the consumer the most efficient products, using the most updated technologies, and to promote these products in the market. In the case of air conditioning, practically all the brands for sale in Brazil belong to global companies, which already offer equipment with higher levels of efficiency in other countries in which they are present. Different from expected, more modern equipment and technology is not necessarily more expensive than inefficient equipment. For example, technological developments and increased efficiency in countries such as South Korea, Japan and India (the latter, at a level of economic development similar to Brazil) were accompanied by reductions in prices.
By investing in the development, production and promotion of more efficient air conditioners, in addition to adding competitive advantages, the industry demonstrates that it is indeed committed to energy sustainability and has a long-term vision both in terms of the market and socio-environmental responsibility.
Where to GET more information
The Kigali Amendment:
The importance of energy efficiency for the economies of countries and for the environment:
The importance of advancing energy efficiency in the air-conditioning sector and its role in energy consumption and global warming:
The means of promoting energy efficiency:
Minimum levels of energy efficiency and labeling:
Proper maintenance and operation of air conditioning systems:
The studies of regulatory impact and their use. Subsidy tools for the evaluation of energy efficiency policies – case studies
The importance of integrating energy efficiency with the transition to lower GWP refrigerants:
Low GWP refrigerant alternatives:
Alternatives for financing energy efficiency in the air conditioning sector: