LB-07-025 -- Binary Enthalpy Wheel Humidification Control in Dedicated Outdoor Air Systems PDF

The central focus of this paper is the operation and control of a total energy recovery device, or enthalpy wheel (EW), during the heating and intermediate seasons when the outside dew-point temperature (DPT) is below the desired supply air DPT. For the most part, control of the EW during hot and humid conditions is being executed properly. On the other hand, experience has shown that the heating season operation is an important and frequently ignored aspect of the energy recovery operation. Consequently, the benefits that are available with proper EW control and operation during the “noncooling” season have been overlooked. So there are no simple and universally accepted EW humidification performance control sequences currently in existence for low DPT, outdoor air conditions (i.e., dry outdoor air conditions). After providing an overview of EW fundamentals, a simple binary EW control is introduced and evaluated in a university campus facility for humidification under dry outdoor air conditions. It was found that use of an EW can reduce the energy consumption for humidification but does not eliminate the potential need for an auxiliary humidifier. Finally, binary control of the EW for supply air temperature control is also addressed.

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