• KaRo (Capillary Tubes) Mats
• Sub-Stations
• Humidity and Dew Point Control
• Controls
• Dedicated Outside Air System and Enthalpy Wheel

Sub-Stations
Sub-stations which consist of pump, valves, expansion tank, heat exchangers, piping and all associated controls based on the load and zone distribution requirements. Central sub-station can be easily mounted on utility room measuring no more than 3' x 6'.

Humidity and Dew Point Control
Humidity is the local and timely changing phenomena containing water in the air, which depends upon the regional climate as well as the individual usage of the rooms such as kitchen, laundries etc

Moist air condenses on cold surfaces because the saturation pressure being a function of the dew point temperature in dependence of the air pressure. This indication influences the application of a cooling ceiling decisively. If the surface is below the dew point, condensation may occurs.

The dew point temperature must be seen in relationship to climatic zones of the location. According to DIN 4710, for our longitudes a yearly average of 60 to 90 hours is assumed, where an outdoor situation with dew point temperature above 16deg° C will occur.

Basically the supply temperatures should be a minimum of 16 deg° C. Therefore the time frame in which theoretically the humidity in the room is the same as the humidity of the outdoor air, is restricted to 4% of the yearly working hours (depending on the location). To exclude this rare case a dew point sensor is installed at the coolest spot in the room. This spot is usually in the farthest corner away from the window directly next to the incoming water line.

Controls
Radiant cooling controls are designed to control both the room temperature and prevent condensation on the chilled ceiling. A two-way valve controls more or less water flow through the system. This supply water is kept at a constant temperature.

To prevent condensation build up, the supply valve is closed as soon as the temperature reaches the dew point as measured by the humidity sensor. thus preventing further water flow into the cooling circuit.

This simple way of regulation is enough to safely avoid condensation in the standard condition. At higher humidity in the room due to individual situations or other related climate situations, dried air must be introduced into the room by means of D.O.A.S. ventilation. The incoming air is conditioned according to the moisture which has to be carried away.

Dedicated Outside Air System and Enthalpy wheel
A new HVAC system called DOAS- Dedicated Outside Air System-conveys 100% outside air to each conditioned space via a constant-volume outside air unit, using total energy recovery. Aside from delivering ventilation air straight to each space, DOAS excels at humidity control and thus nearly eradicates microbial problems and related sick-building issues.

Its outside air unit uses a total energy recovery devices an enthalpy wheel-to cool and dehumidify outside air during summer. This eases the outside air load on the cooling coil by up to 80% and also substantially lessens the required size of the building refrigeration plant, often by over 40%. The enthalpy wheel also works well during winter. It allows the use of smaller winter heating and humidification plants and significantly lowers energy consumption in many geographic areas.

Combined with ceiling radiant cooling, DOAS can diminish the threat of biological and chemical contamination. Since a DOAS/radiant system does not distribute any recirculated air, it will not deliver biological or chemical agents to other parts of the facility. Instead, it dilutes or exhausts them from each individual space.

This technology has already received a favorable government evaluation. In July 2002, the U.S.Depatment of Energy released a report that ranked 55 of the most promising technologies for commercial building HVAC systems and analyzed the top 15 energy saving technologies in detail. Radiant ceiling cooling claimed the number one spot because it uses water, which excels at heat transfer, medium being water instead of air. The second spot went to total energy recovery, while the third place was claimed by D.O.A.S. Indeed, the integration of these three technologies represents an ideal combination, capable of a total energy savings of 1.6 quads-almost equaling the overall savings of the remaining top 12 technologies.

The DOE report also pointed another attractive aspect of the technology. Based on simple payback, both D.O.A.S.and radiant cooling boast zero payback periods.

Penn State University has already put the technology to the test, installing it in a 40 ft. x 80 ft. architectural studio. It has operated in both hot, humid summer conditions and cold winter periods. During summer, it took in outside air of 85 deg. F and 80% relative humidity (148 grains/lb. humidity ratio) and lowered the humidity ratio to 84 grains/lb. During the same period it maintained an operative temperature of 68 deg. F, with outside air temperatures dipping to zero.