This page is designed to help you familiarise yourself with key terminology used throughout the HVAC industry and specifically fan coil units.

Fan Coil Unit (FCU) is an important component of Heating, Ventilation, and Air Conditioning (HVAC) systems. It plays a crucial role in providing localized temperature control, improving indoor air quality, and enhancing overall comfort and efficiency in various types of buildings.

How it operates:

Air is drawn into the FCU by the fan, and as it passes over the heat exchanger, the air is either heated or cooled depending on the system’s operation. If the system is in cooling mode, the heat exchanger absorbs heat from the air, reducing the leaving air temperature. In heating mode, the heat exchanger transfers heat to the air, raising the leaving air temperature.

Once the air has been conditioned by the heat exchanger, the fan then circulates the treated air back into the room, helping maintain a consistent and comfortable indoor environment.

This process ensures that the FCU effectively maintains thermal comfort while being energy-efficient, with the fan working in tandem with the heat exchanger to regulate the room’s temperature based on the specific needs of the space.

 

Here’s why the FCU is considered an important part of HVAC systems:

  1. Flexibility: FCUs are versatile and adaptable to different building types, sizes, and layouts. They can be installed in various configurations (ceiling-mounted, wall-mounted, or floor-mounted) to suit the specific requirements of each space.
  2. Zoning Capabilities: FCUs enable zoning, which means different areas can be controlled independently. This is particularly useful in larger buildings where temperature needs vary between rooms or floors.
  3. Localised Control: FCUs offer individualised temperature control for specific zones or rooms within a building. This allows occupants to adjust the temperature according to their preferences, enhancing comfort and reducing energy waste.
  4. Energy Efficiency: By providing localised control, FCUs can help reduce energy consumption by cooling or heating only the areas that require it. This targeted approach can lead to significant energy savings.
  5. Improved Indoor Air Quality: Many FCUs come equipped with air filters that help remove dust, allergens, and pollutants from the air, contributing to better indoor air quality.
  6. Precise Temperature Control: FCUs can maintain a consistent and precise temperature, ensuring that occupants are comfortable without experiencing drastic temperature fluctuations.
  7. Integration with Building Management Systems: FCUs can be integrated into larger building automation systems, allowing for centralised control, monitoring, and scheduling of HVAC operations.
  8. Reduced Noise Levels: Modern FCUs are designed to operate quietly, minimising disruption to occupants.
  9. Installation and Maintenance: FCUs are relatively easy to install and maintain, making them a practical choice for HVAC systems.
  10. Cost-Effectiveness: FCUs are cost-effective solutions, especially when comparing with Chilled Beam or VAVs.
  11. Heating and Cooling Flexibility: FCUs provide both cooling and heating capabilities, making them suitable for year-round comfort.

 

 Keywords:

Acoustic testing – Measurement of the sound pressures levels Lp for fan coil, to calculate the sound power levels LW for a product tin operation. Usually in a reverberant chamber.

Bespoke fan coil units – Fan coils incorporating project specific design requirements.

BS 8850:2020 – Fan Coil Unit Performance: Determination of Specific Fan Power – Test Method

BS4856 – Methods of Testing and Rating Fan Coil Units; Unit Heaters and Unit Coolers – Thermal, Volumetric, and Acoustic performance.

CIBSE – Chartered Institute of Building Services Engineers

CIBSE TM65 data – An internationally applicable methodology for the calculation of embodied carbon in building services engineering; calculation document that gathers a products sustainability credentials and expressed the products embodied carbon in kg CO2e

Carbon footprint – A carbon footprint (or greenhouse gas footprint) is a calculated value or index that makes it possible to compare the total amount of greenhouse gases that an activity, product, company or country adds to the atmosphere.

Coil – See: Heat exchanger

CPD – Continued Professional development

Eco wire mesh filter – A filter made of wire mesh, as opposed to a synthetic material; typically providing lifetime service and selected to reduce waste product to landfill.

Embodied carbon – Embodied carbon is the greenhouse gas emissions that are created by the construction sector before a building becomes operational.

Energy efficiency – The amount of energy a unit needs to operate, the less energy it needs, the better for the environment

EU2 / G2 – Historical now superseded typical fan coil filtration grades; see ISO 16890, ISO 30% Coarse

Fan coil manufacturer – A company that produces fan coil units

Fan coil unit – A device consisting of a coil and a fan used to heat or cool a room to the desired temperature

FCU – Fan coil unit

Heat exchanger – A finned tubed heat exchanger is a key component in a fan coil; it is a device used to transfer thermal energy between air and a working fluid, in both cooling and heating processes.

HVAC – Heating, Ventilating and Air Conditioning

In-house testing – Fan coil performance testing conducted by our own expert in-house Product Development and Technical team

ISO 16890-1:2013 – Air filter grading.  Technical specifications, requirements and classification system based upon particulate matter efficiency (ePM)

ISO 30% Coarse – Typical fan coil filter media grade.

kg CO2e – Carbon dioxide equivalent; the unit of measurement for the warming effect of greenhouse gases.

Low carbon fan coil – A fan coil unit designed with considerations to minimise its environmental impact by having a low embodied carbon / kg CO2e rating.

NR rating – Acoustic performance of the fan coil unit, using the NR (Noise Rating) curve to determine specific and acceptable noise levels for indoor environments.

Sfp – Specific Fan Power – is a parameter that quantifies the energy-efficiency of fan air movement systems. It is a measure of the electric power that is needed to drive a fan (or collection of fans), relative to the amount of air that is circulated through the fan(s). expressed in Watts per litre per second (W/l/s).

Sound Pressure (Lp) – Sound pressure or acoustic pressure is the local pressure deviation from the ambient (average or equilibrium) atmospheric pressure, caused by a sound wave.

Sound Power (LW) – Sound power is a theoretical value that is not measurable. It is calculated and expressed in Watts and as sound power level LW in decibels (dB).

Specific fan power – SFP

Thermal testing – Measurement of the thermal energy transfer performance.

Volumetric testing – Measurement of the volumetric airflow rate performance.

W/l/s – Expression of electrical power in Watts needed to achieve an airflow rate of 1 litre per second