One of the most important indicators that consumers put in the column “how to choose an air conditioner” is its energy efficiency. That is, it is very important for people to know how much it will cost to heat or cool a room. Often, in search of an answer to how the most economical air conditioner works, people read carefully the specifications of manufacturers, without knowing what the parameters listed there mean. If they do not receive advice from a specialist with extensive experience in the sale and installation of economical air conditioners, there is a serious risk that the chosen solution will not meet the customer expectations.
COP and EER indicators of air conditioners
Until a few years ago, the criteria recorded in air conditioning passports (as well as in trade brochures concerning its efficiency) were the COP (Coefficient Of Performance) conversion factor and the EER (Energy Efficiency Ratio) cooling coefficient. In practice, both show the same thing – the ratio between the heat output of the air conditioner or the heat output of the air conditioner to the electricity consumed by it. Normally there are values above 3, and with good air conditioners they reach 6-7. This means that under certain conditions, such as outdoor temperature +7 ° C for heating, with the correct sizing of the air conditioning system, if COP = 4, the air conditioner will consume 1kW of electricity and will give 4kW of heat. As the outside temperature drops, the power that the system can give off will also decrease, e.g. the COP at -15 ° C, for example, will not be 4, but 2.5, and at a temperature higher than + 7 ° C, it will be higher than 4.
Although the above indicators seem quite sufficient to assess the economy, they do not give an unambiguous answer as to whether the air conditioner will be efficient enough for a particular room throughout the season.
SCOP and SEER indicators of air conditioners
A regulation has been in place in the EU for several years, obliging all manufacturers to indicate the so-called Seasonal Coefficient of Performance (SCOP) and SEER (Seasonal Energy Efficiency Ratio). They take into account the fact that Europe is divided into three climate zones – hot, temperate and cold, and consumers need to be informed about the indicators for their specific zones. Bulgaria falls in the temperate zone. The indicators are not measured at one point (as in COP and EER), but in a whole range from + 16 ° C to -10 ° C for the temperate zone (for heating mode).
Another value that characterizes and guarantees the efficient operation of an air conditioner is Tdesign. The standard allows each manufacturer to determine and declare this temperature, which can be in the range from + 2 ° C to -10 ° C (for the temperate zone). Most manufacturers accept this temperature (for heating) Tdesign = -7 ° C. Mitsubishi Heavy Industries accepts Tdesign = -10 ° C.
What is Tdesign – this is the temperature to which the air conditioner will work efficiently without the need for additional heat source. The lower this temperature, the more efficient the air conditioner.
All manufacturers and traders who want to sell their products in the EU should provide information on the values and temperature conditions under which the seasonal coefficients of the products are calculated, as well as how much the seasonal electricity consumption could be when using the appliance, not in a selected period of the day. In this way, by learning about the values of the seasonal coefficients (SEER and SCOP), as well as calculating what would be the annual electricity consumption of the air conditioner, the consumer will be able to make informed choices and the possibility of being misled by an incompetent or incorrect trader will be reduced to a minimum.
In addition, in order to obtain an objective basis for comparing the models, many other parameters are defined that characterize the environmental conditions when recording these indicators. For example – size and shape of the room, thermal insulation, mode of operation of the air conditioner, partial load, etc.
All air conditioners sold in the EU, including in Bulgaria, must meet a number of European standards and norms. The standard defining the requirements, methodologies and criteria for calculating the seasonal coefficients SCOP in heating mode and SEER in cooling mode (including the thermal insulation of the room) is EN 14825.
Energy class of air conditioners
The well-known energy class, which is indicated in the label of appliances such as air conditioners, stoves, refrigerators, etc. aims to quickly and clearly inform the consumer about their energy efficiency. Normally, this indicator is a direct function of the parameters listed above. Before the introduction of the new regulation in the EU, the value of the energy class depended on the COP / EER and the maximum possible class could be A. After 2013, the labels show SCOP / SEER and, depending on their value, the energy class can reach A +++.
All manufacturers and traders who want to sell their products in the EU should indicate in the energy label information the seasonal electricity consumption when using the appliance. It is this indicator that gives an idea of the efficiency of the appliance in real conditions, as the user can quickly calculate how much heating and cooling will cost him for one season.
Here is an example with a hyperinverter air conditioner, series “Diamond”,
model SRK / SRC25ZSX-S
Cooling capacity, kW: 2.5 (0.9-3.7)
Heating capacity, kW: 3.2 (0.8-5.8)
P designc kW 2.5
Pdesignh (@ -10 ° C) kW: 2.9
SEER / SCOP: 9.60 / 5.20
Energy class heating / cooling: A +++ / A +++
Seasonal energy consumption (cooling / heating) kWh 92/781
At a price of electricity BGN 0.208608 / kWh BGN 19.19. for the cooling season / BGN 162.92 for the heating season
air conditioning efficiency
Provided in this way, the information to the customer about the technical parameters and the conditions under which they are measured, as well as how much will be the seasonal costs, is much more reliable and valuable than looking at the parameters for power and efficiency of air conditioners.