Water-based Indoor Climate Systems, 2007
www.swegon.com
SWEGON WATER BASED CLIMATE SYSTEMS
SWEGON WATER BASED CLIMATE SYSTEMS
DESIGNING WITH SWEGON CLIMATE BEAMS
The principle of Swegon climate beams is that the primary air creates an even mixing effect in the space for the fresh air and additionally, via induction, to circulate the room air through the integrated batteries and thus cool the room air. Different air patterns can be created allowing adaption to different archetectual designs and layouts of the building, the placement of the heat loads and ceiling units.
Corridor – facade (perpendicular to facade)
This installation alternative is well suited for use in cellular offices. The product can be located in any position either centred in the middle of the room or somewhere along one of the wall partitions. Central placement is the conventional alternative that is appropriate for all beams, both with or without supply air and/ heating. Products with or without supply air can be located somewhere along a partition wall. In supply air applications, it may be appropriate to utilize asymmetrical air discharge.
Advantages: Easy connection of water and air to the corridor.
Back (parrallel to facade)
The rear edge solution is well suited for use in cellular offices and open-plan offices. Symmetrical or Asymmetrical air discharge can be selected depending on the volumes of supply air to be discharged. Keeping in mind that the greatest percentage of the heat loads are normally present in the nearest perimeter wall, the air discharged downward acts together with the heat load and this results in excessive air velocity along the floor. At least 50% of the supply air should therefore be aimed toward the perimeter wall and be controlled by means of Anti-Draught Control. Products that radiate heat should normally not be installed at the rear edge of the room. To obtain a small degree of radiant asymmetry, it is advisable to install radiators or radiant heating along the perimeter wall.
Advantages: Easy connection of water and air to the corridor.
Front (parrallel to facade)
The front edge solution is well suited for use in cellular offices and especially in open-plan offices. This location is extremely well suited for products with cooling, supply air and heating function. If the nozzle or disc pressure is high and air is discharged to the zone near the perimeter wall, it is appropriate to use asymmetrical air discharge. If the unit is located nearer to the centre of the room, uniform air discharge works best. Advantages: All the climate functions in a unit are simple to design into the project and install. In an open-plan office, this solution usually enables the fitter to install the products with greater distance from one another than if they are installed aligned in a corridor-to-perimeter wall direction, which may increase opportunity for higher cooling capacities. Allowing space between the short sides of the units offer considerable flexibility when it is time to erect or move partition walls without interfering with the standard of comfort in the room.
Cellular office
In a cellular office, there is always a long mixing zone before the air below room temperature that leaves the ceiling unit reaches the persons in the occupied zone. From the climate beam position, the air can follow the ceiling, wall and part of the floor and mix with room air along this stretch and increase the temperature in the circulated air to in this manner provide a comfortable indoor climate in the premises without risk of draught. Thanks to the long mixing zone, the air volume and impulse can vary within a large range without the risk of draught in the occupied zone becoming too high. This is why the disc configuration need not necessarily be changed if the rate of airflow is changed.
Figure 36. Corridor–perimeter wall-oriented climate beams in cellular offices.
Figure 37. Climate beams installed at the rear edge in cellular offices.
Figure 38. Climate beams installed at the front edge in cellular offices.
Large open-plan rooms
Typical open-plan rooms are shops or open-plan offices. The conditions for climate beams in an open-plan room are different than in an individual office room. In this case, there usually are not any wall surfaces along which the lower-than-room-temperature air currents can flow, other than the perimeter walls, see Figure 39. This is why Anti-Draught Control is always advisable and then particularly in corridor – perimeter wall oriented installations with units that discharge air towards one another. The front-edge placement can also be recommended, see the section above.
With a mixing system there can be a vertical movement between the room air and the cooled supply air. The system must be designed in such a way from the outset to eliminate the risk of draught due to requirements of flexibility relating to furnishings, partition wall placement, etc that are generally required for modern open plan offices. The Swegon calculation software for climate beams, ProSelect, includes all essential data necessary to carry out the design.
Advantages: Products with supply air offer excellent air discharge and mixing performance without disturbing noise and without draught.
To consider: Passive beams should be arranged in the direction of the convection currents, otherwise there is a risk of reduced capacity. In the same way, diffusers should be placed so that they distribute air along the chilled beams. Always specify ADC for the active units.
Figure 39. Locations of climate beams in large open-plan rooms.
DESIGNING WITH SWEGON COMFORT MODULES
A comfort module is a hybrid between a traditional chilled beam, disc air diffuser and a radiator, and combines the following qualities:- The chilled beam’s high cooling and heating capacity when air is supplied at low velocity
- The disc air diffuser’s capacity for quickly mixing supply air with room air
- The radiator’s heating capacity
This unique combination offers completely new capabilities.
The distribution of supply air in four directions (see Figure 40) creates a large mixing zone. This makes it possible to provide high cooling capacities with a product that requires less space in the ceiling.
Cellular offices
A comfort module can be located anywhere in a cellular office without causing draught. By adjusting the air discharge directions of the comfort module based on where the unit is installed, the fitter can optimize the comfort in the room from case to case. A good example of this is a comfort module suspended from the ceiling near the rear-edge of the room (see Figure 41). 4-way air discharge makes it possible to utilize the corridor wall, ceiling and partition walls for mixing supply air with room air. In contrast to traditional two-way air discharge, this provides lower air velocities, especially at floor level.
Benefits: The same product provides optimal comfort regardless its location in the room.
Open-plan rooms
The comfort modules’ 4-way air discharge really shows to advantage in open-plan rooms. Utilizing the built-in ADC (Anti-Draught Control) in the “Fan shape” setting (Figure 40), creates a totally all-round spread pattern. In contrast to the chilled beams’ tendency to locally cause slightly higher air velocities in open-plan rooms, comfort modules distribute air more uniformly throughout the premises. This means less risk of possible draught and better comfort. Since the useful life of the product normally is longer than the intervals between rebuilding or refurbishing buildings, high demands are made on flexible systems. Thanks to the built-in nozzle control function and ADC, there is good chance that you can keep the existing installation even though the indoor comfort considerations change.
Benefits: Highly uniform air distribution and air velocity in the premises. Enormous flexibility in response to airflow rate changes and possible altered room conditions.
Figure 40. 4-way air distribution with the ADC in the Fan-shape setting.
Figure 41. Comfort module located at the rear edge in an office room.
Heating function
New building nowadays involves the construction of perimeter walls with extremely low U value. At the same time, the quality of the windows installed has improved immensely in recent years. This means higher surface temperature on the inside of the window resulting in less radiant cooling energy emission and a minimum of cold downdraught. A much better perimeter wall also reduces the heating requirement in the winter and this means that heat seldom needs to be conveyed to the premises while the room is in use. Internal heating sources are most often sufficient for heating the room during the day. When less radiant cooling energy is emitted from windows, this reduces the need for traditional radiators for increasing the operative temperature.
Since the comfort modules mix supply air faster than a chilled beam, the temperature difference also decreases faster. This in combination with improved structural engineering makes it possible to heat rooms with comfort modules in a better way than with traditional chilled beams. In fact, it is even possible to heat rooms with comfort modules even in many housing improvement projects. The operative temperature and other variables can be calculated very effectively by means of Swegon ProClim software. ProClim is available at Swegon home page www.swegon.com. Detailed full-scale reports that give you an idea of what it may look like in an office room heated by a comfort module are available for you to study. Figure 42 shows an excerpt from an article dealing with simulated winter conditions.
Figure 42. Illustration from full-scale tests involving heating with a comfort module.
DESIGNING WITH SWEGON PERIMETER WALL UNITS
Installation along the perimeter wall
Just as the name implies, the system is mainly intended for location along a perimeter wall. Swegon PRIMO perimeter wall system always includes cooling, heating and ventilation functions. The system provides excellent comfort both while cooling and heating.
Benefits: Complete indoor climate system including control equipment. Well suited for rooms with low ceilings. Little maintenance and low service costs. Offers flexible room solutions that make it possible to move partition walls without upsetting the degree of comfort in the room.
Recessed in floors
Can also be installed horizontally recessed in a raised floor if one exists.
Benefits: Complete indoor climate system including control equipment. Enables solutions with windows that extend down to the floor (so-called glazed facades) yet the installation will not have any effect on the room’s general appearance.
Installation in ceilings
Another alternative involves installing a unit in the front or rear edge of the room. A typical example of this is an installation in a hotel room. In this example, the normal hall section with a suspended ceiling transforms into a room without suspended ceiling. A perimeter wall unit can be installed horizontally in the space above the suspended ceiling in the hall. This unit will provide the room with ventilation, cooling and heating.
Benefits: Complete indoor climate system including control equipment.
Recommended limit values
Recommended limit values for the product are specified at the bottom of the last page of every product section. On the water side, limits are specified for operating pressure and pressure for pressure testing a completed installation. The specified pressures refer to the operating and test pressures of the coils. In most cases, the pipe fittings and valves are the components that limit the total pressure of the system.
The min. permissible water flow is specified for the cooling and heating coil circuits. This refers to the minimal flow required for ensuring that any air remaining in the circuit will be entrained by the liquid. The lowest flow temperature is determined by the dew point temperature and must always be sized so that the system will operate without condensation forming on coil and pipework surfaces. See also the section entitled Condensation protection.
The max. permissible flow temperature indicates the highest temperature recommended for continuous operation. Note that substantial and rapid temperature fluctuations, especially in radiant ceilings but also to a certain degree in climate beams with flanged coils, may give rise to clicking sounds due to linear expansion in components and fitting. High flow temperatures (60-80°C) are only permissible if the need for heating is great and must always follow the outdoor temperature so that the flow temperature will drop as the need for heating diminishes. This is also preferable from an energy-saving point of view since the losses in the pipe system will then be lower.
High temperature systems should be avoided if their room temperature control method involves products continuously being heated up and cooled down.
Figure 43. Perimeter wall units installed below windows in a cellular office.
Figure 44. Ceiling-mounted perimeter wall unit in a hotel room.
Full-scale test in a laboratory