NATURAL CLIMATE SYSTEMS IN HOTELS

Fan coils as a money pit

In order to cover the heating/cooling loads, a significant air volume flow is required, as the energy supply is provided 100 % by the air change (convective). The heating and cooling coils inside the fan coils are relatively small, thus, the system temperatures must be accordingly high for heating (>40 °C) and low for cooling (≈ 7 °C). This excessively dries out the air inside the room and causes a high requirement of latent energy, particularly during cooling.

The high air volume flow and the fans create draft and noise inside the room.

Due to the high output demand of the fan coils, the cold generator must be dimensioned accordingly, which in turn requires larger quantities of cooling agent for the primary circuit.

The entire duct system from the roof to the rooms must be insulated vapor-tight by specialized companies, which causes high investment costs.

To be able to cover the output demand continuously, the filters and wear parts of the fan coils must be replaced regularly, which increases the repair and maintenance costs.

In spite of their outdated and uneconomic technology, fan coils continue to be the first choice for air-conditioning hotel rooms, as conventional ceiling systems cannot achieve the required output due to their inertia and the excessive humidity during cooling.

Disadvantages of fan coils

The energy exchange, i.e. heating and cooling, is performed 100 % via the air by means of convective energy transfer. The heating and cooling coils inside the fan coil are relatively small, thus, the system temperatures must be accordingly high for heating (>40 °C) and low for cooling (≈ 7 °C). This excessively dries out the air inside the room and causes high energy costs.

Due to the high output demand of the fan coils, the cold generator must be dimensioned accordingly, which in turn requires larger quantities of cooling agent for the primary circuit.

The entire duct system from the roof to the rooms must be insulated vapor-tight by specialized companies, which causes high investment costs.

The fans create draft and noise inside the room.

For the optimum performance of the units over a long term, the filters and wear parts of the fan coils must be replaced regularly, which increases the repair and maintenance costs.

In spite of their outdated and uneconomic technology, fan coils continue to be the first choice for air-conditioning hotel rooms, as conventional ceiling cooling cannot achieve the required output due to the issue of condensation water. In addition to this, the relative humidity of the air increases to an uncomfortable range.

The solution: Natural climate ceiling by ArgillaTherm

The natural climate ceilings control the temperature of the rooms at a similar rate as the fan coils. This is owed to the system structure, a special control concept and the highly conductive base material, the HUMID modules. Learn more here.

Moisture control, particularly during cooling, is provided naturally, without requiring latent energy. A moisture storage of up to 1.7 l/m² per module area is available for this. This reduces the utility costs significantly and does not dry out the rooms excessively.

As the output can be generated independent of the air volume flow, the change rates can be reduced by approximately 50 %. Reference value for the energy supply is the sufficient discharge of CO₂ inside the rooms and not the air volume flow, as per usual. At our latitude, this makes central ventilation systems redundant, as the low air volumes can be covered reliably by means of decentralized solutions.

The different system concepts with decentralized ventilation, with significantly reduced central ventilation, as well as central ventilation with dehumidification of the fresh air are compiled below.

System concept ArgillaTherm/SIEGENIA

The natural climate ceilings by ArgillaTherm take over the heating, cooling, and humidity control inside the rooms. Decentralized facade ventilators by SIEGENIA (respectively one AEROMAT VT with heat recovery, filter technology and CO₂ sensor per room) are used for the discharge of CO₂, moisture, and pollutants. The interior bathrooms will be equipped with an air extraction device, which is only in operation during occupancy (approx. 1 hour per day incl. run-on time). When the bathrooms are occupied, both motors of the facade ventilators are operating in supply air mode, so that the required air volume for the extraction is provided (priority switching of the bathroom).

Compared to the standard concept “Fan coils/central ventilation”, the investment costs are reduced by around 20 %, whereas the maintenance, operation and utility costs are lowered by approximately 60 %.

System concept ArgillaTherm/central ventilation

If a central ventilation system is desired and designed for the required lower air volume flow, the investment costs are reduced by almost 10 %, while the maintenance, operating and utility costs are decreased by almost 40 % compared to the standard “fan coil/central ventilation” concept.

System concept ArgillaTherm/central ventilation with dehumidification of the fresh air

In countries with considerably high moisture loads, the fresh air supply has to be dehumidified. Usually, room temperatures of < 20 °C are desired here. In this case, the natural climate ceilings provide the temperature and humidity control inside the room, which are created by the persons present inside the room. As the cooling capacity cannot be generated via air volume flow, the change rates can also be reduced by approximately 50 % here. Reference value remains the sufficient discharge of CO₂ inside the rooms.

Compared to the standard concept “Fan coils/central ventilation”, the investment costs are reduced by around 10 %, whereas the maintenance, operation and utility costs are lowered by roughly 40 %. For a hotel project in Singapore with 580 rooms, cost savings in ongoing operations of approximately € 1 million annually could be generated, which corresponds to a return on investment of 3 years.

Comparison calculator for hotel projects worldwide

We would be happy to prepare a comparative calculation for your project. Please provide the following information:

• Location
• Layouts
• Number of rooms with average volume and information on the exterior surface (windows/shading/facade). 
• Cooling days throughout the year with their exterior parameters (temperature and dew point profile).

The assessment includes the load determination for the guest rooms with the required values for covering the output. Additionally, the expenditures for the operation of all facilities and for the sensible, latent, and cooling water energy will be determined.

ArgillaTherm is an expert for the equipment of hotels. The natural climate ceilings were installed in The Circus Hotel Berlin, for instance. Ventilation is provided naturally via the windows here.

Overview of the disadvantages of fan coils:

• High operating and utility costs due to high air volume flow and requirement of latent energy.
• High installation effort due to required infrastructure.
• High repair and maintenance costs.
• Requires a lot of space.
• Noise.
• Air flow.
• Unhealthy, dry room air in summer and particularly during winter.
• Unpleasant eco-balance.

An energy-efficient air-conditioning system not only contributes to a reduction of the operating costs, but also improves the environmental profile of the hotel, which is an important competitive advantage in times of increasing ecological consciousness of the guests.

System configuration

The overall structure height is only 55 mm. This system can be mounted directly to the ceiling or suspended from the ceiling by means of lathing or suspenders, as desired.

Installation options

Full-surface ceiling covering with slanted ceiling

Exposed beam ceiling