From nominal efficiency…
Up until now, the energy efficiency of cooling and heating devices is measured in artificial, standardised conditions. For air conditioners, for instance, this is done at a constant temperature of 35 °C and at full cooling capacity. This is the nominal energy efficiency which, clearly, does not accurately represents how air conditioners are used on a daily basis.
via the real world…
In reality, energy consumption fluctuates with the outside temperature, which can vary significantly throughout an entire heating or cooling season. Even in midsummer, cooling is not always needed. At such times, the power consumption of standby modes should also be included for accurate measurements.
to seasonal efficiency
This is what seasonal efficiency is all about: a cyclical energy efficiency measure taking into account fluctuating temperatures. Smart air conditioners and heat pumps will hardly ever need their full capacity, as they are able to continuously adapt their cooling and heating capacity to outside conditions. And smart air conditioners and heat pumps are what Daikin is all about.
The difference between nominal and seasonal efficiency is one between static lab tests and real-life use. A difference found for all kinds of products. For instance, using your car’s advertised fuel/mileage ratio to plan your trips might lead to unpleasant surprises. A full petrol tank of 60 liters would in principle take you 1,000 km far, from Paris to Berlin or Barcelona. But…would it really?
Lab tests, lap tests and…reality
The advertised, nominal efficiency numbers are the result of measurements in stable, laboratory conditions. With a full tank you will certainly be able to drive the 1,000 kilometers by taking about 300 laps on the Monte Carlo race circuit in Monaco on a windless day, at constant speed. Real-life, day-to-day conditions are of course very different, and road grades and wind can seriously influence your car’s efficiency.
Things are quite similar for heat pumps and air conditioners. Seasonal efficiency measurements take into account many of the climate-related road bumps, slopes and wind differences. Accurate and reliable, the seasonal efficiency measure avoids any unpleasant surprises on your energy bills.
During the summer, sometimes temperatures can indeed rise to 35 °C, the temperature at which nominal efficiency is measured in the lab. But very often temperatures will circle around 25°C for a large part of the entire cooling season. Sometimes they will even drop below the average room temperature of 21°C. Likewise, European winters have more to offer than unvaried scenery of snow and ice. Seasonal efficiency takes all these trend differences into account to build a real-life, longer term approximation of the true energy efficiency of air conditioners and heat pumps.
Of course, the seasonal efficiency of a heat pump or air conditioner will differ between regions with an average winter temperature of -5 °C versus those with + 5 °C or +15 °C. Because average summer or winter temperatures are very different in Helsinki, Paris or Athens, there are different seasonal efficiency values for each of the climate regions these cities can be found. The difference will reflect in the new energy labels, which will come into force 01/01/2013. This way, a true insight on you energy bill can be guaranteed.