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Alternatives in climate control

Andrews Sykes’ UK HVAC sales director, Paul La Roche, discusses the advantages of fan coils and air handling units (AHUs) and what you should expect from a typical configuration.

When people consider HVAC systems, they tend to think of conventional air conditioning or heating units as the sole source of climate control while completely overlooking the role that air handlers and fan coils often play.

Fan coils and air handlers both deliver total climate control by running on either chiller or hot water, depending on the requirement.

AHUs are commonly part of a commercial heating, ventilation or air conditioning system and will deliver heated or cooled air into a target location so that it can be distributed throughout an intended space.

In some cases, air handlers may even have built-in filters to remove impurities from the air and can have a significant impact in delivering safe and comfortable climate control across a applications.

Older air handlers may only operate at one speed but most modern units offer variable speed settings to allow adjustment as demands change. A number of factors can affect the volume of cooling or heating required including the outdoor ambient temperature, business requirements, the room’s capacity and even the condition of air filters.

A variable speed air handler therefore gives users a great degree of flexibility and allows you to control conditions more accurately. These units operate almost constantly at lower speeds and provide various benefits in the process:

Consistent cooling – rather than producing large blasts of cool air like traditional air handling units, variable speed models will fluctuate according to the requirement at any particular moment. This prevents noticeable temperature swings and enables a far more consistent cooling process.

Improved air quality – variable speed aid handlers distribute air through filters extremely frequently because they have longer operating cycles. This means the environment in which the unit is deployed will benefit from a better quality of air because it is being continually filtered.

Economical performance – air handlers that only run at high speed will consume significant quantities of energy due to the fact they have to turn on and off recurrently. Variable speed air handlers, by contrast, generally use a lot less power because they run at lower speeds, cycle less often and only consume energy when required to be in use.

Low noise operation – by running at lower speeds, modern air handlers are generally quiet in operation whilst also turning on and off far less regularly than older models.

Fewer maintenance requirements – naturally, less on and off cycling will cause significantly less wear and tear than one-speed air handlers, ensuring longer operating lives and greater reliability for longer.

Although there are some similarities between fan coils and air handling units – and they remain a critical characteristic of many HVAC systems – there are also some discernible differences.

Fan coils are generally connected to an existing chilled or hot water circuit and deployed in smaller areas to control the temperature. The simplicity and cost-effectiveness of a fan coil means it is often preferred to central heating systems with air handlers, although both units offer several advantages.

These units contain a fan which draws air inside before passing over a cooling or heating coil. Commonly used inside office buildings, shopping centres, marquees and computer rooms, fan coils are also fitted with fan speed controllers and internal condensate pumps for effective temperature regulation.

In recent years, the installation of fan coil units has become one of the most popular methods of providing air conditioning and heating for commercial or private premises, and there are several advantages of this:

High capacities – substantial cooling and heating capacities despite fan coils being smaller in size and having a vastly reduced distribution network when compared with all-air systems.

Individual zone control – strategic deployment of fan coils within a targeted environment simplifies controlling the temperature of an individual space.

Maximum flexibility – fan coils allow for future changes in load to be easily accommodated and are particularly suited to applications where medium to high cooling loads are required.

The use of air handlers and fan coils is extremely widespread in many industries largely because of the efficiency associated with using them. Air handlers can be connected together in a series or parallel arrangement to provide multimegawatt solutions.

Before choosing an air distribution unit for your business or process, you should ascertain that the equipment has been designed and built to feature the latest technology including energy conserving motors, three-way thermostatic valves and variable speed fans.

Your chosen provider should offer an all-encompassing range covering any conceivable flow rate, with high capacity units capable of distributing volumes that exceed 50,000m³/h. Another overlooked benefit of both fan coils and air handlers is their relative manoeuvrability, facilitating quick redeployment should your circumstances change.

A trustworthy supplier will conduct regular maintenance of their equipment and oversee thorough cleaning and servicing prior to installing them on your site. This safety check, although a necessity in its own right, will help maximise the efficiency of your cooling or heating system once in operation to ensure you get the most from whatever solution you have in place.


29 July 2020


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