Economic and technical comparison for cooling in hotel rooms

In the course of a scientific paper, a comparison of the systems between induction units and fan coils with EC technology was made. Due to the low noise emission, both systems are frequently chosen solutions for decentralised hotel air conditioning, but they both reveal in themselves advantages and disadvantages. The aim of the study was to compare the economic and technical differences of both systems for cooling hotel bedrooms.

Subject-matter of the scientific study

Under due consideration of the VDI (Association of German Engineers) standard 2067 “Economic efficiency of building installations”, various parameters were defined and a calculation model was created. The subject-matter of the study was a fictitious hotel building with various numbers and sizes of rooms. The following aspects were studied on the basis of the defined parameters:

• Electric energy consumption
• Heating and cooling energy requirements
• Investment, repairs and maintenance costs

Comparison of both systems at a glance

In conclusion, it can be ascertained that a concrete comparison of both systems always depends on the corresponding volumetric loads. As there are great fluctuations in the primary air volume flow required when designing the induction units, great differences emerge in the power consumption as well as in the investment costs.

The comparison of the overall costs of both systems revealed, however, that fan coils are the less expensive option with virtually identical investments costs. One reason is the higher power consumption of the centralised ventilation device when using induction units. What is more, subsequent expenditure for wear parts, such as the fan, do not let the total cost of fan coil units exceed the total cost of a system with induction units over the period under review.

A further aspect is the size of the centralised ventilation unit. If the statutory requirements of Stage 2 of the Energy-related Products (ErP) Directive 2018 are taken into consideration, the centralised ventilation units will have to be around 30 % larger to transport the same air volumes. Correspondingly any anticipated additional costs relating to the size of the unit have not yet been taken into consideration

Induction unit

• Higher investment costs due to the larger duct networks and shafts
• According to the new Energy-related Products (ErP) Directive 2016 / 2018, the centralised ventilation unit requires approx. 30 % more space to transport the same air volume
• Induction units are approx. 1/3 larger than fan coil units
• Higher air volume needed than the minimum air volume required to discharge the humidity and CO2 loads produced in the room
• Low sound emissions (operation at stage 2: 22 – 30 dB(A))
• Ease of maintenance, no maintenance costs due to filter change

Fan coil units

• Lower investment costs
• Smaller space requirement (installation in the suspended ceiling)
• Energy savings due to decentralised air conditioning of the hotel bedrooms (only as much primary air as is needed) and thanks to high-performance heat recovery
• Low sound emissions (< 20 – 33 dB(A))
• Low maintenance costs through the use of regenerative filters
• Ease of maintenance

You can access the full report with a presentation of the results here.

Download of the functional comparison