Manufacturers often declare different types of cooling capacity information in their documentation. This means that in many cases, customers compare apples to oranges. Here we explain how different cooling capacities are denoted by numbers differently and therefore – what to look out for when comparing them.
Gross cooling capacity is produced by the air conditioning system through a heat exchanger. Fans are used to move air through the air conditioning system. This consumes energy, which is eventually converted into heat. This heat, also produced in the air conditioning system, reduces the gross cooling capacity. The result is net cooling capacity.
Modern precision air conditioning systems cool the air without drying it out. Therefore, the entire generated cooler is used precisely for what is needed: air cooling. In older air conditioners and those that do not have components of ideal size or have a poor solution for the returned air, part of the generated cooling capacity is improperly used for air drying during the cooling process. There is a loss of useful cooling capacity and the air conditioning system works less efficiently.
The sum of generated capacity is called total cooling capacity. The part that is specifically used to cool the air is called the sensible cooling capacity. Any part of the cooling capacity used inefficiently for air drying is called latent cooling capacity. Ideally, without unwanted drying, the sensitive cooling capacity is equal to the total cooling capacity. The ratio of sensitive refrigerant to total cooling capacity is called “sensible heat ratio” or SHR for short. In ideal conditions, without removing moisture from the air, the SHR coefficient is 1.0.
So, as you can see, it is essential to be careful when comparing similar to similar when comparing technical data. If you are not sure whether the manufacturer’s documentation refers to the gross total capacity or the effective, usable net capacity, it is worth asking before comparing data from different manufacturers.
From the site of our partner “STULZ” – a world leader in the production of precision air conditioning
Author: Benjamin Petschke