Aircon service
Energy Efficiency of Air Conditioners –Explained
Air conditioners have becomeindispensable and an essential part of life. Home, office, shopping malls,hospitals, and colleges – all rely on air conditioners to make the environmentcomfortable. Aircons consume a lot of energy, and it is, therefore, essentialto understand the efficiency of an aircon. Owning a higher efficiency airconditioner can save annually hundreds of dollars in electricity bills. Thisarticle to savemoney how electricilty bills monthly on aircon consumption.
Efficiency rating of an air conditioner
Air conditioners are rated instars (or ticks) depending on location. A higher star-rated air conditionerconsumes lesser energy to provide the same amount of cooling than an airconwith lesser star-rating.
The government of a countrytypically decides the star-rating specifications. A threshold is defined forevery rating which is the minimum efficiency required to earn that star. Theefficiency of aircon is measured as a ratio called the Energy Efficiency Ratio (EER). Higher the EER, the greater is theefficiency of the unit.
We shall have a glance into the working of an airconditioner before defining EER.
Air Conditioner – A heat exchanger
An aircon is a heat pump. Itconsists of the condenser, the evaporator, refrigerant gas, and the heatexchanger coils. Just like a refrigerator, the aircon pumps heat from the roomand vents it off with the ambient air outside.
Energy Efficiency Ratio (EER)
This number indicates how muchheat the air conditioner removes from the area to be cooled relative to theenergy consumed by it. A higher EER means a better air conditioner
Energy Efficiency Ratio = Heat Removed by thesystem / Energy consumed by the system
Energy is measured in Joules(J). If an air conditioner consumes 1000 joules of energy to pump out 3200joules of energy from the room, its energy efficiency ratio is 3200/1000 = 3.2
Since electricity is meteredas power consumed, EER can also be expressed as “cooling power”.
Energy Efficiency Ratio = Cooling Power of theAC / Power Consumption of the AC
“CoolingPower” can be understood as the heat removed by the aircon every second. Poweris measured in Watts (W),and you maycome across this term in the technical specifications of an air conditioner. Itreflects the amount of energy removed by the system in one second of operation.
Itbecomes evident that an air conditioner that provides higher cooling powercompared to others, for the same power consumption, is more efficient.
Star Rating Compared
The following data compares theenergy consumed by a 1.0-ton air conditioner (based on annual electricityconsumption). This data is only for comparison and reflect typical powerconsumption. Values would differ across different brands of air conditioners.
Typical Power Consumption of a 1.0-ton aircon calculated on an annual usage basis
Star Rating Power Consumption Power Saving Cumulative Power Saving Power Saving (%) compared to previous star-rated AC Power Saving (%) compared to 1-star rated AC
1-star 843 W Zero Zero Zero Zero
2-stars 800 W 43 W 43 W 5.10 % 5.10 %
3-stars 747 W 53 W 96 W 6.62 % 11.38 %
4-stars 645 W 102 W 198 W 13.65 % 23.48 %
5-stars 554 W 91 W 289 W 14.10 % 34.28 %
The data indicates that a 5-starrated aircon consumes 34.28 % less energy than a 1-star rated aircon. Saidanother way, four 5-star rated air conditioners would consume approximately thesame power as three 1-star rated air conditioners. This translates directly tocapacity too. These four 5-star rated aircons can provide 4 tons of coolingcompared to the 3 tons supplied by the 1-star aircons, for similar powerconsumption.
It must be noted that a higherstar rating also means a more expensive air conditioner. Higher efficiencyparts cost more and have newer technology, which means higher cost.
EER – Example
Referenced from: https://www.hitachiaircon.in/ranges/inverter-split-acs/Toushi-3100S
Consider the Hitachi Toushi 3100S air conditioner. We shallexamine the energy efficiency of the 1.0-ton unit. For simplicity, we shallconsider the rated capacities instead of maximum capacity. Do you want to know aircon energysaving tips ?
Rated Cooling Capacity (at 100 % load) = 3516 Watts(12000 BTU/hour, or 1.0 ton)
Rated Power Consumption (at 100 % load) = 1110 Watts
Energy Efficiency Ratio = 3516 / 1110 = 3.16
These numbers indicate the powerconsumed to pump out heat from the room. If you visit the link provided belowthe table, you will find a number designated ISEER, which represents the“Indian Seasonal” Energy Efficiency Ratio. It considers the reduction in powerconsumption when the outside air is cooler (spring season compared to thesummers).
How to make a purchase decision
Air conditioners are expensivebut durable appliances. You should consider your budget and coolingrequirements (number of hours of use per day). Tell me more on how bigair conditioneris needed. If a higher star-rated aircon has a higherinitial cost than the additional electricity consumed by the lower model, youcould consider buying the more economical model. This is Return on Investment(ROI) calculation.
Anaverage air conditioner easily lasts eight to ten years whenmaintained properly. Return on investment considers a shorter time frame.Assuming energy costs would increase over the lifetime of the air conditioner,you would almost certainly save money in the long-run with a more efficient airconditioner.
Ifyou are planning to use the aircon for a short duration, you could save moneywith a cheaper and lesser rated air conditioner.
Saving electricity meansburning lesser fossil fuel. You would help not only your finances but also theplanet. We recommend buying a higher star-rated air conditioner since thebenefits would certainly outweigh the costs in the long run.
Conclusion
Energy Efficiency Ratio (EER) is a measure of the airconditioner’s efficiency. When comparing air conditioners from differentbrands, use the formula to calculate the EER. Manufacturers may report EERdifferently based on their assumptions. However, cooling power and electricalpower consumption are reported accurately in watts. A division of those wouldgive you the EER, and that would help compare and decide why aircon you want topurchase.
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