4

Inlet Moisture (gr/lb)

Fig. 39-26 Performance Plots for System Example. Source: Munters Cargocaire and Mason Grant Company ture at various locations. Note that the 800 cfm (22.6 m3/m) of incoming outside air (Location A) balances 500 cfm of exhaust (14.2 m3/m) at Location G and 300 cfm (8.5 m3/m) of air leakage. This system's controls are as follows:

• Room air pressure is controlled by a differential pressure controller, which automatically adjusts the fresh air intake damper. As air pressure exceeds the set differential, the damper begins to close to reduce incoming air.

• Dehumidifier capacity is controlled by a bypass damper that passes air around the system as humidity levels are less than design conditions. As a dewpoint controller signals a humidity change, the bypass damper is modulated.

• Desiccant system energy use is controlled by a temperature controller in the reactivation airstream. This minimizes energy use by reducing the energy of the reactivation heaters when the temperature rises above the set point of 120°F (49°C), which indicates that all of the moisture absorbed on the process air side has been desorbed in reactivation.

• Chilled water flow through the outside air precooling coil is controlled by a three-way valve, which responds to a controller located downstream of the coil that is set at 50°F (10°C). The post-cooling coil, which sets the final delivered air temperature, is controlled in the same manner, with the temperature sensor located in the conditioned space to maintain constant temperature. In a variable flow system, two-way valves could be used to accomplish this control function more economically.

• A supply air heating coil is used to provide heat whenever room temperature drops below 68°F (20°C). This is controlled by the same sensor that controls the post-cooling coil.

Bypass only at low load m

300 cfm leaves the room through cracks and doors

Renewable Energy 101

Renewable Energy 101

Renewable energy is energy that is generated from sunlight, rain, tides, geothermal heat and wind. These sources are naturally and constantly replenished, which is why they are deemed as renewable. The usage of renewable energy sources is very important when considering the sustainability of the existing energy usage of the world. While there is currently an abundance of non-renewable energy sources, such as nuclear fuels, these energy sources are depleting. In addition to being a non-renewable supply, the non-renewable energy sources release emissions into the air, which has an adverse effect on the environment.

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