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Energy analysis for improved efficiency

There are a few ways of evaluating energy usage in heating and cooling applications. They are all valid in their own way, but it is important to remember that they evaluate energy efficiency in different ways and that they should be used in different situations depending on your needs.

Method One: SEER/SCOP

The first indexes set up for measuring and comparing energy efficiency were EER (for chillers) and COP (for heat pumps). The problem with these indexes, though, are that they are measuring the effect at full load, which is not very representative for comfort applications where the load varies greatly over the year. The European Commission instead developed and launched seasonal indexes, SEER and SCOP, which take this into consideration.

SEER and SCOP provide the legal levels for energy efficiency in the EU, and are also excellent when you need to compare different products from multiple manufacturers. However: the indexes do not take different ambient conditions (even they can be calculated using 3 different thermal profiles, those are never identical to the different cities’ ones) or user needs into consideration, and give no indication as to how well the units actually perform within your system.

Method Two: Energy consumption calculation

To gain an estimation on how well the unit actually will perform, you will need to calculate the energy consumption. This is a number based on two things: a city profile, which takes into consideration the conditions at your geographical site; and a load profile, based on how the unit is to be used. This is done in a software tool (in the case of Swegon, our tool is called CH Design) where customers can test different configurations. The result is a simulated, estimated energy consumption number.

The number is pretty accurate, but often not precisely identical to how the unit will perform in reality. In the field, conditions may vary in some ways. For example, inertia in the plant, or different parts of the system being exposed to the sun or not, may result in varying real-life consumption. But the number is close enough to reality to give an indication as to how well it will perform.

Method Three: On-site measurements

To get precise energy consumption results, you have to measure the system on site. Adding measurement tools is an option every manufacturer provides (for example, BlueThink software platform from Swegon offers a number of dedicated solutions). With a tool in place, you can change variables on site and measure the effects. You can also see how age affects the unit by measuring and comparing performance over time. This is the only way to measure how the unit actually will perform.

So, to summarize, there are basically three different ways of evaluating energy performance, and they each have their specific target and scope. But whichever method you need to use, Swegon has the tools to help you.