Air Conditioning in Offices with Dual-Flow Ventilation

Comfort in offices is more than important, because it also influences two essential aspects in the work environment: safety and productivity. However, how to achieve the best climatic comfort in buildings intended for work? Unfortunately, in many of them, an abusive use of air conditioning in offices is made, with high bills for the use of air conditioning and heating.

A solution for this is mechanical dual-flow ventilation, which in addition to renewing the air and providing it with much higher quality, can also climatize the spaces in a manner directly related to energy efficiency.

First of all, to find an ideal solution for air conditioning in offices, two requirements that cannot be evaded are usually posed:

1. Lighting. If solar light can be harnessed, energy savings will be very significant. Artificial light is one of the major costs in offices, and it also significantly influences air conditioning.
2. Air renewal and its quality. This requirement is primarily based on maintaining good health among workers. If situations of stale air occur in offices, it is possible that the staff may fall ill or that bacteria may multiply.

In addition to these two initial requirements that cannot be avoided, harnessing solar light and good ventilation, we must take into account the energy expenditure produced in buildings. The Energy Foundation of the Community of Madrid provides us with approximate data regarding how energy consumption is distributed in the capital's offices:

• Summer cooling consumption: 30% of the total.
• Lighting: 28% of the total.
• Winter heating: 20% of the total.
• Computers and IT systems: 4% of the total.
• Other expenditures that do not reach 3% of consumption.

These figures make it clear that, in addition to artificial light -another element where energy efficiency strategies are required-, consumption for air conditioning is certainly the highest. Using air conditioning and heating systems requires the highest consumption.

However, in many cases, consumption is exaggerated and results from an abuse of air conditioning systems. What climate should we have in the office? According to the RITE, offices should be around 21ºC to 25ºC of dry temperature, with a range of 45% to 65% relative humidity and an air velocity of 0.2 to 0.5 m/s. If these conditions are met, it is considered that the office building is in a state of comfort. And for all this, the air conditioning system is necessary.

To provide the best air conditioning in offices, dual-flow ventilation systems can offer a much less costly and more comfortable alternative. So, how do we address ventilation in office buildings?

Mechanical Ventilation for Office Air Conditioning

Historically, in office ventilation, the question was what time of day the windows would be opened. Sometimes, it was suggested that the best time was in the morning, to allow fresh air to enter before employees arrived. Today, ventilation goes much further and is carried out constantly with the windows closed.

Additionally, it is mandatory to have mechanical ventilation systems nowadays, as air renewal is necessary at all times. First of all, it should be differentiated between two types of spaces in offices:

1. Monozone ventilation scheme: a single fan controls a room, such as a meeting room.
2. Multizone ventilation scheme: the same fan controls several spaces, adapting to demand based on the information collected by the sensors.

The problem many offices suffer from, unfortunately, is that in summer the air conditioning is so strong that it makes it cold and in winter the heat is too high due to heating. To avoid these problems, mechanical dual-flow ventilation can also serve to climatize offices.

The primary function of dual-flow ventilation is to ensure air renewal and the necessary flow rate. It adapts at all times to the real needs of the workplace, and extracts air that has lost quality. It also introduces high-quality air from the outside that has been previously filtered.

The air conditioning in offices with dual-flow ventilation is achieved through the use of heat recovery units, which installed in the mechanical ventilation system temper the air that enters from the outside. It works both in winter and summer, managing to reduce the need for traditional air conditioning units at many moments, thus achieving a way to temper the spaces with energy efficiency, without suffering great expenses on energy bills.