CB Aqua:

The CB Aqua is a standard solution, which covers 80% of all applications.

 

The system consists of:

   - Metal ceiling panels
   - Heat Conduction Rails (HCR) / Bonding
   - Copper tubing
   - Acoustic blankets or fleece (optional)
   - Flexible hoses

The CB Aqua system is highly versatile. As each building differs in size, location, usage, cooling-heating demands, etc., the CB Aqua system can be configured to meet the toughest demands, while still ensuring the highest possible thermal comfort for a high quality indoor environment.

 

Basic System Design

Cross-section with standard panel

Cross-section with alternative panel

 

The CB Aqua system can be applied with a large variety of ceiling panels (preferably metal) and is not limited to a specific ceiling manufacturer. The design cooling/heating capacity is defined by the total number of active ceiling panels installed (typically 60-70% of the ceiling area), the width of the HCRs (64mm ˜ 2 1/2” or 84mm ˜ 3 1/3”), the spacing of the HCRs (typically 150mm ˜ 6”) and the design temperatures of the supply water (typical range cooling; 13°C-18°C, 55°F-65°F, heating; 30°C-38°C, 86°F-100°F).

The active panels can be fitted with sprinkler heads, smoke detectors, spotlights, etc. on site, or the panels can be delivered with precut openings. Larger openings, as for diffusers, etc. should be precut by the ceiling manufacturer.

A typical configuration for conventional ceiling systems (2’x2’ or 2’x4’, 600x600mm or 600x1200mm) consists of 4-10 active panels, which are connected in series with flexible hoses. The hoses are fitted with push-on couplings, which allows a very quick and simple installation of the system. The active rows are then connected to the water circuit in parallel. A control valve in the return line sets the volume flow rate accordingly from 0-100%, depending on the capacity required. The system poses no restrictions to the size of the control zone. The control strategy can range from individual room-by-room controllers to a completely automated Building Management System.


Basic System Function

 

Cooling Mode:
As the control valve opens, chilled water starts circulating in the copper tubing and removes the heat stored in the ceiling (panel, HCR, copper) by means of conduction. As a result the surface temperature of the ceiling decreases, which immediately starts the process of radiation exchange from the warmer objects (people, computers, etc.) in the room to the cooler surface of the ceiling. Due to the temperature difference of the room air in the boundary layer below the ceiling and the surface temperature of the ceiling, natural convection is generated, which increases the resulting cooling capacity of the system. Natural convection is based on the buoyancy of air, which varies according to its temperature (cool air sinks, warm air rises). The air velocity which results from natural convection is normally well below the threshold of draft occurrence in the occupied zone. On average, 70% of the cooling capacity is based on radiation and 30% on convection. Heat, which is absorbed by the ceiling, is removed from the room by the chilled water (conduction). The CB Aqua system is generally designed for a temperature differential of 2°C (˜4°F) between the supply and return water temperatures.

The room temperature decreases until the set point of the thermostat is achieved. To prevent the room temperature from sinking further, the control valve starts closing, reducing the volume flow rate through the ceiling and therefore reducing the capacity of the system until steady state conditions are achieved. Due to a special bonding technique, which enables very high heat transfer rates, response times to changing room conditions (in- decreased heat loads) are virtually only dependant on the response time of the control system.

The Barcol-Air Radiant Cooling Video (Home-page) shows the function of the CB Aqua ceiling with animated images, as well as real-time infrared images, which illustrate how quick a chilled ceiling reacts, once the cooling valve opens.

 

Heating Mode:
Heating with the CB Aqua system functions in the same manner as cooling, with opposite signs. The natural convection is reduced and the primary mode of heat transfer is by radiation. The supply water temperatures are much lower than heating water used in conventional wall mounted radiators. The system is typically laid out for temperatures ranging from 30°C-40°C, 86°F-104°C. The resulting heating capacity is equivalent to radiators operated at much higher temperatures, due to the larger transfer surface available with the ceiling. The lower supply water temperatures offer significant energy saving potential, as well as a much higher thermal comfort, due to a uniform heat distribution throughout the room. In applications with large glass surfaces along the perimeter, a separate heating circuit (1-2 panels wide) operated at higher temperatures can compensate skin losses, thus allowing the building core zone to be operated at optimal conditions.


The Components

Ceiling panels:
Ceiling panels are available in a large range of sizes and patterns. Standard panel sizes are 2’x2’ or 2’x4’. Lengths vary from 1ft to 12ft (size can vary depending on manufacturer). The panel thickness is typically 22-24 gauge for steel, and 18-20 gage for aluminum panels. The weight as installed varies from 1lb/ft2 to 2lb/ft2 (excl. acoustic blanket). The panels are fitted with a rugged powder coating, available in a large variety of colors. Specific details can be supplied by ceiling manufacturers.

 

Calibrated Copper Tubing:
The standard coil diameter is 12mm. To ensure a high precision fit in the HCR, the copper is calibrated and hardened. The 0.7mm thickness guarantees that no metal fatigue can occur in the bends. The large diameter allows small pressure drops or bigger circuit and eliminates the risk of blockages or noise from water circulation. Barcol-Air uses highest quality copper, which has been tested for flaws (Eddy-current test), to ensure that absolutely no leakage will occur during the entire lifespan of the products

 

Heat Conduction Rail (HCR):
HCR’s are high precision extruded aluminum profiles. To prevent the HCR from “shining” through the perforation (especially when indirect lighting systems are used) the bottom side of the HCR is coated with a very thin coat of flat black paint, or anodized in black. Standard HCR’s are 2.5” (64mm) or 3.3” (84mm) wide. For gypsum applications there is an optional 4.2” (107mm) HCR available. The HCR’s are cut to length, for an optimal fit on the ceiling panel. Standard lengths can range up to 16’ (5m).

 

Bonding:
3M Very High Bonding Tape ensures a highly efficient heat transfer between panel and HCR. The bonding tape is permanently elastic and allows different material expansion rates. Simulated life cycle tests performed on the bonding show that even after 20 years of operation, no measurable reduction of the heat transfer rate or the adhesion can be detected. The heat transfer is 100 % reproducible, which ensures that the cooling capacity is the same in the laboratory as on the job site!

 

The key to high performance radiant panels lays in the quality/precision of the individual components and the know-how in the production process! Strict adherence to precisely defined / controlled production processes ensure long term operational reliability and 100% reproducible system performance during the entire life cycle of the product!